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TOMOYO Linux Cross Reference
Linux/kernel/trace/ftrace.c

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  1 /*
  2  * Infrastructure for profiling code inserted by 'gcc -pg'.
  3  *
  4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
  5  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
  6  *
  7  * Originally ported from the -rt patch by:
  8  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
  9  *
 10  * Based on code in the latency_tracer, that is:
 11  *
 12  *  Copyright (C) 2004-2006 Ingo Molnar
 13  *  Copyright (C) 2004 Nadia Yvette Chambers
 14  */
 15 
 16 #include <linux/stop_machine.h>
 17 #include <linux/clocksource.h>
 18 #include <linux/sched/task.h>
 19 #include <linux/kallsyms.h>
 20 #include <linux/seq_file.h>
 21 #include <linux/suspend.h>
 22 #include <linux/tracefs.h>
 23 #include <linux/hardirq.h>
 24 #include <linux/kthread.h>
 25 #include <linux/uaccess.h>
 26 #include <linux/bsearch.h>
 27 #include <linux/module.h>
 28 #include <linux/ftrace.h>
 29 #include <linux/sysctl.h>
 30 #include <linux/slab.h>
 31 #include <linux/ctype.h>
 32 #include <linux/sort.h>
 33 #include <linux/list.h>
 34 #include <linux/hash.h>
 35 #include <linux/rcupdate.h>
 36 
 37 #include <trace/events/sched.h>
 38 
 39 #include <asm/sections.h>
 40 #include <asm/setup.h>
 41 
 42 #include "trace_output.h"
 43 #include "trace_stat.h"
 44 
 45 #define FTRACE_WARN_ON(cond)                    \
 46         ({                                      \
 47                 int ___r = cond;                \
 48                 if (WARN_ON(___r))              \
 49                         ftrace_kill();          \
 50                 ___r;                           \
 51         })
 52 
 53 #define FTRACE_WARN_ON_ONCE(cond)               \
 54         ({                                      \
 55                 int ___r = cond;                \
 56                 if (WARN_ON_ONCE(___r))         \
 57                         ftrace_kill();          \
 58                 ___r;                           \
 59         })
 60 
 61 /* hash bits for specific function selection */
 62 #define FTRACE_HASH_BITS 7
 63 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
 64 #define FTRACE_HASH_DEFAULT_BITS 10
 65 #define FTRACE_HASH_MAX_BITS 12
 66 
 67 #ifdef CONFIG_DYNAMIC_FTRACE
 68 #define INIT_OPS_HASH(opsname)  \
 69         .func_hash              = &opsname.local_hash,                  \
 70         .local_hash.regex_lock  = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
 71 #define ASSIGN_OPS_HASH(opsname, val) \
 72         .func_hash              = val, \
 73         .local_hash.regex_lock  = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
 74 #else
 75 #define INIT_OPS_HASH(opsname)
 76 #define ASSIGN_OPS_HASH(opsname, val)
 77 #endif
 78 
 79 static struct ftrace_ops ftrace_list_end __read_mostly = {
 80         .func           = ftrace_stub,
 81         .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
 82         INIT_OPS_HASH(ftrace_list_end)
 83 };
 84 
 85 /* ftrace_enabled is a method to turn ftrace on or off */
 86 int ftrace_enabled __read_mostly;
 87 static int last_ftrace_enabled;
 88 
 89 /* Current function tracing op */
 90 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
 91 /* What to set function_trace_op to */
 92 static struct ftrace_ops *set_function_trace_op;
 93 
 94 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
 95 {
 96         struct trace_array *tr;
 97 
 98         if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
 99                 return false;
100 
101         tr = ops->private;
102 
103         return tr->function_pids != NULL;
104 }
105 
106 static void ftrace_update_trampoline(struct ftrace_ops *ops);
107 
108 /*
109  * ftrace_disabled is set when an anomaly is discovered.
110  * ftrace_disabled is much stronger than ftrace_enabled.
111  */
112 static int ftrace_disabled __read_mostly;
113 
114 static DEFINE_MUTEX(ftrace_lock);
115 
116 static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
117 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
118 static struct ftrace_ops global_ops;
119 
120 #if ARCH_SUPPORTS_FTRACE_OPS
121 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
122                                  struct ftrace_ops *op, struct pt_regs *regs);
123 #else
124 /* See comment below, where ftrace_ops_list_func is defined */
125 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
126 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
127 #endif
128 
129 /*
130  * Traverse the ftrace_global_list, invoking all entries.  The reason that we
131  * can use rcu_dereference_raw_notrace() is that elements removed from this list
132  * are simply leaked, so there is no need to interact with a grace-period
133  * mechanism.  The rcu_dereference_raw_notrace() calls are needed to handle
134  * concurrent insertions into the ftrace_global_list.
135  *
136  * Silly Alpha and silly pointer-speculation compiler optimizations!
137  */
138 #define do_for_each_ftrace_op(op, list)                 \
139         op = rcu_dereference_raw_notrace(list);                 \
140         do
141 
142 /*
143  * Optimized for just a single item in the list (as that is the normal case).
144  */
145 #define while_for_each_ftrace_op(op)                            \
146         while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&  \
147                unlikely((op) != &ftrace_list_end))
148 
149 static inline void ftrace_ops_init(struct ftrace_ops *ops)
150 {
151 #ifdef CONFIG_DYNAMIC_FTRACE
152         if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
153                 mutex_init(&ops->local_hash.regex_lock);
154                 ops->func_hash = &ops->local_hash;
155                 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
156         }
157 #endif
158 }
159 
160 /**
161  * ftrace_nr_registered_ops - return number of ops registered
162  *
163  * Returns the number of ftrace_ops registered and tracing functions
164  */
165 int ftrace_nr_registered_ops(void)
166 {
167         struct ftrace_ops *ops;
168         int cnt = 0;
169 
170         mutex_lock(&ftrace_lock);
171 
172         for (ops = rcu_dereference_protected(ftrace_ops_list,
173                                              lockdep_is_held(&ftrace_lock));
174              ops != &ftrace_list_end;
175              ops = rcu_dereference_protected(ops->next,
176                                              lockdep_is_held(&ftrace_lock)))
177                 cnt++;
178 
179         mutex_unlock(&ftrace_lock);
180 
181         return cnt;
182 }
183 
184 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
185                             struct ftrace_ops *op, struct pt_regs *regs)
186 {
187         struct trace_array *tr = op->private;
188 
189         if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
190                 return;
191 
192         op->saved_func(ip, parent_ip, op, regs);
193 }
194 
195 /**
196  * clear_ftrace_function - reset the ftrace function
197  *
198  * This NULLs the ftrace function and in essence stops
199  * tracing.  There may be lag
200  */
201 void clear_ftrace_function(void)
202 {
203         ftrace_trace_function = ftrace_stub;
204 }
205 
206 static void ftrace_sync(struct work_struct *work)
207 {
208         /*
209          * This function is just a stub to implement a hard force
210          * of synchronize_sched(). This requires synchronizing
211          * tasks even in userspace and idle.
212          *
213          * Yes, function tracing is rude.
214          */
215 }
216 
217 static void ftrace_sync_ipi(void *data)
218 {
219         /* Probably not needed, but do it anyway */
220         smp_rmb();
221 }
222 
223 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
224 static void update_function_graph_func(void);
225 
226 /* Both enabled by default (can be cleared by function_graph tracer flags */
227 static bool fgraph_sleep_time = true;
228 static bool fgraph_graph_time = true;
229 
230 #else
231 static inline void update_function_graph_func(void) { }
232 #endif
233 
234 
235 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
236 {
237         /*
238          * If this is a dynamic, RCU, or per CPU ops, or we force list func,
239          * then it needs to call the list anyway.
240          */
241         if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
242             FTRACE_FORCE_LIST_FUNC)
243                 return ftrace_ops_list_func;
244 
245         return ftrace_ops_get_func(ops);
246 }
247 
248 static void update_ftrace_function(void)
249 {
250         ftrace_func_t func;
251 
252         /*
253          * Prepare the ftrace_ops that the arch callback will use.
254          * If there's only one ftrace_ops registered, the ftrace_ops_list
255          * will point to the ops we want.
256          */
257         set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
258                                                 lockdep_is_held(&ftrace_lock));
259 
260         /* If there's no ftrace_ops registered, just call the stub function */
261         if (set_function_trace_op == &ftrace_list_end) {
262                 func = ftrace_stub;
263 
264         /*
265          * If we are at the end of the list and this ops is
266          * recursion safe and not dynamic and the arch supports passing ops,
267          * then have the mcount trampoline call the function directly.
268          */
269         } else if (rcu_dereference_protected(ftrace_ops_list->next,
270                         lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
271                 func = ftrace_ops_get_list_func(ftrace_ops_list);
272 
273         } else {
274                 /* Just use the default ftrace_ops */
275                 set_function_trace_op = &ftrace_list_end;
276                 func = ftrace_ops_list_func;
277         }
278 
279         update_function_graph_func();
280 
281         /* If there's no change, then do nothing more here */
282         if (ftrace_trace_function == func)
283                 return;
284 
285         /*
286          * If we are using the list function, it doesn't care
287          * about the function_trace_ops.
288          */
289         if (func == ftrace_ops_list_func) {
290                 ftrace_trace_function = func;
291                 /*
292                  * Don't even bother setting function_trace_ops,
293                  * it would be racy to do so anyway.
294                  */
295                 return;
296         }
297 
298 #ifndef CONFIG_DYNAMIC_FTRACE
299         /*
300          * For static tracing, we need to be a bit more careful.
301          * The function change takes affect immediately. Thus,
302          * we need to coorditate the setting of the function_trace_ops
303          * with the setting of the ftrace_trace_function.
304          *
305          * Set the function to the list ops, which will call the
306          * function we want, albeit indirectly, but it handles the
307          * ftrace_ops and doesn't depend on function_trace_op.
308          */
309         ftrace_trace_function = ftrace_ops_list_func;
310         /*
311          * Make sure all CPUs see this. Yes this is slow, but static
312          * tracing is slow and nasty to have enabled.
313          */
314         schedule_on_each_cpu(ftrace_sync);
315         /* Now all cpus are using the list ops. */
316         function_trace_op = set_function_trace_op;
317         /* Make sure the function_trace_op is visible on all CPUs */
318         smp_wmb();
319         /* Nasty way to force a rmb on all cpus */
320         smp_call_function(ftrace_sync_ipi, NULL, 1);
321         /* OK, we are all set to update the ftrace_trace_function now! */
322 #endif /* !CONFIG_DYNAMIC_FTRACE */
323 
324         ftrace_trace_function = func;
325 }
326 
327 int using_ftrace_ops_list_func(void)
328 {
329         return ftrace_trace_function == ftrace_ops_list_func;
330 }
331 
332 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
333                            struct ftrace_ops *ops)
334 {
335         rcu_assign_pointer(ops->next, *list);
336 
337         /*
338          * We are entering ops into the list but another
339          * CPU might be walking that list. We need to make sure
340          * the ops->next pointer is valid before another CPU sees
341          * the ops pointer included into the list.
342          */
343         rcu_assign_pointer(*list, ops);
344 }
345 
346 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
347                              struct ftrace_ops *ops)
348 {
349         struct ftrace_ops **p;
350 
351         /*
352          * If we are removing the last function, then simply point
353          * to the ftrace_stub.
354          */
355         if (rcu_dereference_protected(*list,
356                         lockdep_is_held(&ftrace_lock)) == ops &&
357             rcu_dereference_protected(ops->next,
358                         lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
359                 *list = &ftrace_list_end;
360                 return 0;
361         }
362 
363         for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
364                 if (*p == ops)
365                         break;
366 
367         if (*p != ops)
368                 return -1;
369 
370         *p = (*p)->next;
371         return 0;
372 }
373 
374 static void ftrace_update_trampoline(struct ftrace_ops *ops);
375 
376 static int __register_ftrace_function(struct ftrace_ops *ops)
377 {
378         if (ops->flags & FTRACE_OPS_FL_DELETED)
379                 return -EINVAL;
380 
381         if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
382                 return -EBUSY;
383 
384 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
385         /*
386          * If the ftrace_ops specifies SAVE_REGS, then it only can be used
387          * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
388          * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
389          */
390         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
391             !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
392                 return -EINVAL;
393 
394         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
395                 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
396 #endif
397 
398         if (!core_kernel_data((unsigned long)ops))
399                 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
400 
401         add_ftrace_ops(&ftrace_ops_list, ops);
402 
403         /* Always save the function, and reset at unregistering */
404         ops->saved_func = ops->func;
405 
406         if (ftrace_pids_enabled(ops))
407                 ops->func = ftrace_pid_func;
408 
409         ftrace_update_trampoline(ops);
410 
411         if (ftrace_enabled)
412                 update_ftrace_function();
413 
414         return 0;
415 }
416 
417 static int __unregister_ftrace_function(struct ftrace_ops *ops)
418 {
419         int ret;
420 
421         if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
422                 return -EBUSY;
423 
424         ret = remove_ftrace_ops(&ftrace_ops_list, ops);
425 
426         if (ret < 0)
427                 return ret;
428 
429         if (ftrace_enabled)
430                 update_ftrace_function();
431 
432         ops->func = ops->saved_func;
433 
434         return 0;
435 }
436 
437 static void ftrace_update_pid_func(void)
438 {
439         struct ftrace_ops *op;
440 
441         /* Only do something if we are tracing something */
442         if (ftrace_trace_function == ftrace_stub)
443                 return;
444 
445         do_for_each_ftrace_op(op, ftrace_ops_list) {
446                 if (op->flags & FTRACE_OPS_FL_PID) {
447                         op->func = ftrace_pids_enabled(op) ?
448                                 ftrace_pid_func : op->saved_func;
449                         ftrace_update_trampoline(op);
450                 }
451         } while_for_each_ftrace_op(op);
452 
453         update_ftrace_function();
454 }
455 
456 #ifdef CONFIG_FUNCTION_PROFILER
457 struct ftrace_profile {
458         struct hlist_node               node;
459         unsigned long                   ip;
460         unsigned long                   counter;
461 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
462         unsigned long long              time;
463         unsigned long long              time_squared;
464 #endif
465 };
466 
467 struct ftrace_profile_page {
468         struct ftrace_profile_page      *next;
469         unsigned long                   index;
470         struct ftrace_profile           records[];
471 };
472 
473 struct ftrace_profile_stat {
474         atomic_t                        disabled;
475         struct hlist_head               *hash;
476         struct ftrace_profile_page      *pages;
477         struct ftrace_profile_page      *start;
478         struct tracer_stat              stat;
479 };
480 
481 #define PROFILE_RECORDS_SIZE                                            \
482         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
483 
484 #define PROFILES_PER_PAGE                                       \
485         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
486 
487 static int ftrace_profile_enabled __read_mostly;
488 
489 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
490 static DEFINE_MUTEX(ftrace_profile_lock);
491 
492 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
493 
494 #define FTRACE_PROFILE_HASH_BITS 10
495 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
496 
497 static void *
498 function_stat_next(void *v, int idx)
499 {
500         struct ftrace_profile *rec = v;
501         struct ftrace_profile_page *pg;
502 
503         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
504 
505  again:
506         if (idx != 0)
507                 rec++;
508 
509         if ((void *)rec >= (void *)&pg->records[pg->index]) {
510                 pg = pg->next;
511                 if (!pg)
512                         return NULL;
513                 rec = &pg->records[0];
514                 if (!rec->counter)
515                         goto again;
516         }
517 
518         return rec;
519 }
520 
521 static void *function_stat_start(struct tracer_stat *trace)
522 {
523         struct ftrace_profile_stat *stat =
524                 container_of(trace, struct ftrace_profile_stat, stat);
525 
526         if (!stat || !stat->start)
527                 return NULL;
528 
529         return function_stat_next(&stat->start->records[0], 0);
530 }
531 
532 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
533 /* function graph compares on total time */
534 static int function_stat_cmp(void *p1, void *p2)
535 {
536         struct ftrace_profile *a = p1;
537         struct ftrace_profile *b = p2;
538 
539         if (a->time < b->time)
540                 return -1;
541         if (a->time > b->time)
542                 return 1;
543         else
544                 return 0;
545 }
546 #else
547 /* not function graph compares against hits */
548 static int function_stat_cmp(void *p1, void *p2)
549 {
550         struct ftrace_profile *a = p1;
551         struct ftrace_profile *b = p2;
552 
553         if (a->counter < b->counter)
554                 return -1;
555         if (a->counter > b->counter)
556                 return 1;
557         else
558                 return 0;
559 }
560 #endif
561 
562 static int function_stat_headers(struct seq_file *m)
563 {
564 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
565         seq_puts(m, "  Function                               "
566                  "Hit    Time            Avg             s^2\n"
567                     "  --------                               "
568                  "---    ----            ---             ---\n");
569 #else
570         seq_puts(m, "  Function                               Hit\n"
571                     "  --------                               ---\n");
572 #endif
573         return 0;
574 }
575 
576 static int function_stat_show(struct seq_file *m, void *v)
577 {
578         struct ftrace_profile *rec = v;
579         char str[KSYM_SYMBOL_LEN];
580         int ret = 0;
581 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
582         static struct trace_seq s;
583         unsigned long long avg;
584         unsigned long long stddev;
585 #endif
586         mutex_lock(&ftrace_profile_lock);
587 
588         /* we raced with function_profile_reset() */
589         if (unlikely(rec->counter == 0)) {
590                 ret = -EBUSY;
591                 goto out;
592         }
593 
594 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
595         avg = rec->time;
596         do_div(avg, rec->counter);
597         if (tracing_thresh && (avg < tracing_thresh))
598                 goto out;
599 #endif
600 
601         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
602         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
603 
604 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
605         seq_puts(m, "    ");
606 
607         /* Sample standard deviation (s^2) */
608         if (rec->counter <= 1)
609                 stddev = 0;
610         else {
611                 /*
612                  * Apply Welford's method:
613                  * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
614                  */
615                 stddev = rec->counter * rec->time_squared -
616                          rec->time * rec->time;
617 
618                 /*
619                  * Divide only 1000 for ns^2 -> us^2 conversion.
620                  * trace_print_graph_duration will divide 1000 again.
621                  */
622                 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
623         }
624 
625         trace_seq_init(&s);
626         trace_print_graph_duration(rec->time, &s);
627         trace_seq_puts(&s, "    ");
628         trace_print_graph_duration(avg, &s);
629         trace_seq_puts(&s, "    ");
630         trace_print_graph_duration(stddev, &s);
631         trace_print_seq(m, &s);
632 #endif
633         seq_putc(m, '\n');
634 out:
635         mutex_unlock(&ftrace_profile_lock);
636 
637         return ret;
638 }
639 
640 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
641 {
642         struct ftrace_profile_page *pg;
643 
644         pg = stat->pages = stat->start;
645 
646         while (pg) {
647                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
648                 pg->index = 0;
649                 pg = pg->next;
650         }
651 
652         memset(stat->hash, 0,
653                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
654 }
655 
656 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
657 {
658         struct ftrace_profile_page *pg;
659         int functions;
660         int pages;
661         int i;
662 
663         /* If we already allocated, do nothing */
664         if (stat->pages)
665                 return 0;
666 
667         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
668         if (!stat->pages)
669                 return -ENOMEM;
670 
671 #ifdef CONFIG_DYNAMIC_FTRACE
672         functions = ftrace_update_tot_cnt;
673 #else
674         /*
675          * We do not know the number of functions that exist because
676          * dynamic tracing is what counts them. With past experience
677          * we have around 20K functions. That should be more than enough.
678          * It is highly unlikely we will execute every function in
679          * the kernel.
680          */
681         functions = 20000;
682 #endif
683 
684         pg = stat->start = stat->pages;
685 
686         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
687 
688         for (i = 1; i < pages; i++) {
689                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
690                 if (!pg->next)
691                         goto out_free;
692                 pg = pg->next;
693         }
694 
695         return 0;
696 
697  out_free:
698         pg = stat->start;
699         while (pg) {
700                 unsigned long tmp = (unsigned long)pg;
701 
702                 pg = pg->next;
703                 free_page(tmp);
704         }
705 
706         stat->pages = NULL;
707         stat->start = NULL;
708 
709         return -ENOMEM;
710 }
711 
712 static int ftrace_profile_init_cpu(int cpu)
713 {
714         struct ftrace_profile_stat *stat;
715         int size;
716 
717         stat = &per_cpu(ftrace_profile_stats, cpu);
718 
719         if (stat->hash) {
720                 /* If the profile is already created, simply reset it */
721                 ftrace_profile_reset(stat);
722                 return 0;
723         }
724 
725         /*
726          * We are profiling all functions, but usually only a few thousand
727          * functions are hit. We'll make a hash of 1024 items.
728          */
729         size = FTRACE_PROFILE_HASH_SIZE;
730 
731         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
732 
733         if (!stat->hash)
734                 return -ENOMEM;
735 
736         /* Preallocate the function profiling pages */
737         if (ftrace_profile_pages_init(stat) < 0) {
738                 kfree(stat->hash);
739                 stat->hash = NULL;
740                 return -ENOMEM;
741         }
742 
743         return 0;
744 }
745 
746 static int ftrace_profile_init(void)
747 {
748         int cpu;
749         int ret = 0;
750 
751         for_each_possible_cpu(cpu) {
752                 ret = ftrace_profile_init_cpu(cpu);
753                 if (ret)
754                         break;
755         }
756 
757         return ret;
758 }
759 
760 /* interrupts must be disabled */
761 static struct ftrace_profile *
762 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
763 {
764         struct ftrace_profile *rec;
765         struct hlist_head *hhd;
766         unsigned long key;
767 
768         key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
769         hhd = &stat->hash[key];
770 
771         if (hlist_empty(hhd))
772                 return NULL;
773 
774         hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
775                 if (rec->ip == ip)
776                         return rec;
777         }
778 
779         return NULL;
780 }
781 
782 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
783                                struct ftrace_profile *rec)
784 {
785         unsigned long key;
786 
787         key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
788         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
789 }
790 
791 /*
792  * The memory is already allocated, this simply finds a new record to use.
793  */
794 static struct ftrace_profile *
795 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
796 {
797         struct ftrace_profile *rec = NULL;
798 
799         /* prevent recursion (from NMIs) */
800         if (atomic_inc_return(&stat->disabled) != 1)
801                 goto out;
802 
803         /*
804          * Try to find the function again since an NMI
805          * could have added it
806          */
807         rec = ftrace_find_profiled_func(stat, ip);
808         if (rec)
809                 goto out;
810 
811         if (stat->pages->index == PROFILES_PER_PAGE) {
812                 if (!stat->pages->next)
813                         goto out;
814                 stat->pages = stat->pages->next;
815         }
816 
817         rec = &stat->pages->records[stat->pages->index++];
818         rec->ip = ip;
819         ftrace_add_profile(stat, rec);
820 
821  out:
822         atomic_dec(&stat->disabled);
823 
824         return rec;
825 }
826 
827 static void
828 function_profile_call(unsigned long ip, unsigned long parent_ip,
829                       struct ftrace_ops *ops, struct pt_regs *regs)
830 {
831         struct ftrace_profile_stat *stat;
832         struct ftrace_profile *rec;
833         unsigned long flags;
834 
835         if (!ftrace_profile_enabled)
836                 return;
837 
838         local_irq_save(flags);
839 
840         stat = this_cpu_ptr(&ftrace_profile_stats);
841         if (!stat->hash || !ftrace_profile_enabled)
842                 goto out;
843 
844         rec = ftrace_find_profiled_func(stat, ip);
845         if (!rec) {
846                 rec = ftrace_profile_alloc(stat, ip);
847                 if (!rec)
848                         goto out;
849         }
850 
851         rec->counter++;
852  out:
853         local_irq_restore(flags);
854 }
855 
856 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
857 static int profile_graph_entry(struct ftrace_graph_ent *trace)
858 {
859         int index = trace->depth;
860 
861         function_profile_call(trace->func, 0, NULL, NULL);
862 
863         /* If function graph is shutting down, ret_stack can be NULL */
864         if (!current->ret_stack)
865                 return 0;
866 
867         if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
868                 current->ret_stack[index].subtime = 0;
869 
870         return 1;
871 }
872 
873 static void profile_graph_return(struct ftrace_graph_ret *trace)
874 {
875         struct ftrace_profile_stat *stat;
876         unsigned long long calltime;
877         struct ftrace_profile *rec;
878         unsigned long flags;
879 
880         local_irq_save(flags);
881         stat = this_cpu_ptr(&ftrace_profile_stats);
882         if (!stat->hash || !ftrace_profile_enabled)
883                 goto out;
884 
885         /* If the calltime was zero'd ignore it */
886         if (!trace->calltime)
887                 goto out;
888 
889         calltime = trace->rettime - trace->calltime;
890 
891         if (!fgraph_graph_time) {
892                 int index;
893 
894                 index = trace->depth;
895 
896                 /* Append this call time to the parent time to subtract */
897                 if (index)
898                         current->ret_stack[index - 1].subtime += calltime;
899 
900                 if (current->ret_stack[index].subtime < calltime)
901                         calltime -= current->ret_stack[index].subtime;
902                 else
903                         calltime = 0;
904         }
905 
906         rec = ftrace_find_profiled_func(stat, trace->func);
907         if (rec) {
908                 rec->time += calltime;
909                 rec->time_squared += calltime * calltime;
910         }
911 
912  out:
913         local_irq_restore(flags);
914 }
915 
916 static int register_ftrace_profiler(void)
917 {
918         return register_ftrace_graph(&profile_graph_return,
919                                      &profile_graph_entry);
920 }
921 
922 static void unregister_ftrace_profiler(void)
923 {
924         unregister_ftrace_graph();
925 }
926 #else
927 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
928         .func           = function_profile_call,
929         .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
930         INIT_OPS_HASH(ftrace_profile_ops)
931 };
932 
933 static int register_ftrace_profiler(void)
934 {
935         return register_ftrace_function(&ftrace_profile_ops);
936 }
937 
938 static void unregister_ftrace_profiler(void)
939 {
940         unregister_ftrace_function(&ftrace_profile_ops);
941 }
942 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
943 
944 static ssize_t
945 ftrace_profile_write(struct file *filp, const char __user *ubuf,
946                      size_t cnt, loff_t *ppos)
947 {
948         unsigned long val;
949         int ret;
950 
951         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
952         if (ret)
953                 return ret;
954 
955         val = !!val;
956 
957         mutex_lock(&ftrace_profile_lock);
958         if (ftrace_profile_enabled ^ val) {
959                 if (val) {
960                         ret = ftrace_profile_init();
961                         if (ret < 0) {
962                                 cnt = ret;
963                                 goto out;
964                         }
965 
966                         ret = register_ftrace_profiler();
967                         if (ret < 0) {
968                                 cnt = ret;
969                                 goto out;
970                         }
971                         ftrace_profile_enabled = 1;
972                 } else {
973                         ftrace_profile_enabled = 0;
974                         /*
975                          * unregister_ftrace_profiler calls stop_machine
976                          * so this acts like an synchronize_sched.
977                          */
978                         unregister_ftrace_profiler();
979                 }
980         }
981  out:
982         mutex_unlock(&ftrace_profile_lock);
983 
984         *ppos += cnt;
985 
986         return cnt;
987 }
988 
989 static ssize_t
990 ftrace_profile_read(struct file *filp, char __user *ubuf,
991                      size_t cnt, loff_t *ppos)
992 {
993         char buf[64];           /* big enough to hold a number */
994         int r;
995 
996         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
997         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
998 }
999 
1000 static const struct file_operations ftrace_profile_fops = {
1001         .open           = tracing_open_generic,
1002         .read           = ftrace_profile_read,
1003         .write          = ftrace_profile_write,
1004         .llseek         = default_llseek,
1005 };
1006 
1007 /* used to initialize the real stat files */
1008 static struct tracer_stat function_stats __initdata = {
1009         .name           = "functions",
1010         .stat_start     = function_stat_start,
1011         .stat_next      = function_stat_next,
1012         .stat_cmp       = function_stat_cmp,
1013         .stat_headers   = function_stat_headers,
1014         .stat_show      = function_stat_show
1015 };
1016 
1017 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1018 {
1019         struct ftrace_profile_stat *stat;
1020         struct dentry *entry;
1021         char *name;
1022         int ret;
1023         int cpu;
1024 
1025         for_each_possible_cpu(cpu) {
1026                 stat = &per_cpu(ftrace_profile_stats, cpu);
1027 
1028                 name = kasprintf(GFP_KERNEL, "function%d", cpu);
1029                 if (!name) {
1030                         /*
1031                          * The files created are permanent, if something happens
1032                          * we still do not free memory.
1033                          */
1034                         WARN(1,
1035                              "Could not allocate stat file for cpu %d\n",
1036                              cpu);
1037                         return;
1038                 }
1039                 stat->stat = function_stats;
1040                 stat->stat.name = name;
1041                 ret = register_stat_tracer(&stat->stat);
1042                 if (ret) {
1043                         WARN(1,
1044                              "Could not register function stat for cpu %d\n",
1045                              cpu);
1046                         kfree(name);
1047                         return;
1048                 }
1049         }
1050 
1051         entry = tracefs_create_file("function_profile_enabled", 0644,
1052                                     d_tracer, NULL, &ftrace_profile_fops);
1053         if (!entry)
1054                 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
1055 }
1056 
1057 #else /* CONFIG_FUNCTION_PROFILER */
1058 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1059 {
1060 }
1061 #endif /* CONFIG_FUNCTION_PROFILER */
1062 
1063 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1064 
1065 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1066 static int ftrace_graph_active;
1067 #else
1068 # define ftrace_graph_active 0
1069 #endif
1070 
1071 #ifdef CONFIG_DYNAMIC_FTRACE
1072 
1073 static struct ftrace_ops *removed_ops;
1074 
1075 /*
1076  * Set when doing a global update, like enabling all recs or disabling them.
1077  * It is not set when just updating a single ftrace_ops.
1078  */
1079 static bool update_all_ops;
1080 
1081 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1082 # error Dynamic ftrace depends on MCOUNT_RECORD
1083 #endif
1084 
1085 struct ftrace_func_entry {
1086         struct hlist_node hlist;
1087         unsigned long ip;
1088 };
1089 
1090 struct ftrace_func_probe {
1091         struct ftrace_probe_ops *probe_ops;
1092         struct ftrace_ops       ops;
1093         struct trace_array      *tr;
1094         struct list_head        list;
1095         void                    *data;
1096         int                     ref;
1097 };
1098 
1099 /*
1100  * We make these constant because no one should touch them,
1101  * but they are used as the default "empty hash", to avoid allocating
1102  * it all the time. These are in a read only section such that if
1103  * anyone does try to modify it, it will cause an exception.
1104  */
1105 static const struct hlist_head empty_buckets[1];
1106 static const struct ftrace_hash empty_hash = {
1107         .buckets = (struct hlist_head *)empty_buckets,
1108 };
1109 #define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
1110 
1111 static struct ftrace_ops global_ops = {
1112         .func                           = ftrace_stub,
1113         .local_hash.notrace_hash        = EMPTY_HASH,
1114         .local_hash.filter_hash         = EMPTY_HASH,
1115         INIT_OPS_HASH(global_ops)
1116         .flags                          = FTRACE_OPS_FL_RECURSION_SAFE |
1117                                           FTRACE_OPS_FL_INITIALIZED |
1118                                           FTRACE_OPS_FL_PID,
1119 };
1120 
1121 /*
1122  * Used by the stack undwinder to know about dynamic ftrace trampolines.
1123  */
1124 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1125 {
1126         struct ftrace_ops *op = NULL;
1127 
1128         /*
1129          * Some of the ops may be dynamically allocated,
1130          * they are freed after a synchronize_sched().
1131          */
1132         preempt_disable_notrace();
1133 
1134         do_for_each_ftrace_op(op, ftrace_ops_list) {
1135                 /*
1136                  * This is to check for dynamically allocated trampolines.
1137                  * Trampolines that are in kernel text will have
1138                  * core_kernel_text() return true.
1139                  */
1140                 if (op->trampoline && op->trampoline_size)
1141                         if (addr >= op->trampoline &&
1142                             addr < op->trampoline + op->trampoline_size) {
1143                                 preempt_enable_notrace();
1144                                 return op;
1145                         }
1146         } while_for_each_ftrace_op(op);
1147         preempt_enable_notrace();
1148 
1149         return NULL;
1150 }
1151 
1152 /*
1153  * This is used by __kernel_text_address() to return true if the
1154  * address is on a dynamically allocated trampoline that would
1155  * not return true for either core_kernel_text() or
1156  * is_module_text_address().
1157  */
1158 bool is_ftrace_trampoline(unsigned long addr)
1159 {
1160         return ftrace_ops_trampoline(addr) != NULL;
1161 }
1162 
1163 struct ftrace_page {
1164         struct ftrace_page      *next;
1165         struct dyn_ftrace       *records;
1166         int                     index;
1167         int                     size;
1168 };
1169 
1170 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1171 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1172 
1173 /* estimate from running different kernels */
1174 #define NR_TO_INIT              10000
1175 
1176 static struct ftrace_page       *ftrace_pages_start;
1177 static struct ftrace_page       *ftrace_pages;
1178 
1179 static __always_inline unsigned long
1180 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1181 {
1182         if (hash->size_bits > 0)
1183                 return hash_long(ip, hash->size_bits);
1184 
1185         return 0;
1186 }
1187 
1188 /* Only use this function if ftrace_hash_empty() has already been tested */
1189 static __always_inline struct ftrace_func_entry *
1190 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1191 {
1192         unsigned long key;
1193         struct ftrace_func_entry *entry;
1194         struct hlist_head *hhd;
1195 
1196         key = ftrace_hash_key(hash, ip);
1197         hhd = &hash->buckets[key];
1198 
1199         hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1200                 if (entry->ip == ip)
1201                         return entry;
1202         }
1203         return NULL;
1204 }
1205 
1206 /**
1207  * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1208  * @hash: The hash to look at
1209  * @ip: The instruction pointer to test
1210  *
1211  * Search a given @hash to see if a given instruction pointer (@ip)
1212  * exists in it.
1213  *
1214  * Returns the entry that holds the @ip if found. NULL otherwise.
1215  */
1216 struct ftrace_func_entry *
1217 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1218 {
1219         if (ftrace_hash_empty(hash))
1220                 return NULL;
1221 
1222         return __ftrace_lookup_ip(hash, ip);
1223 }
1224 
1225 static void __add_hash_entry(struct ftrace_hash *hash,
1226                              struct ftrace_func_entry *entry)
1227 {
1228         struct hlist_head *hhd;
1229         unsigned long key;
1230 
1231         key = ftrace_hash_key(hash, entry->ip);
1232         hhd = &hash->buckets[key];
1233         hlist_add_head(&entry->hlist, hhd);
1234         hash->count++;
1235 }
1236 
1237 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1238 {
1239         struct ftrace_func_entry *entry;
1240 
1241         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1242         if (!entry)
1243                 return -ENOMEM;
1244 
1245         entry->ip = ip;
1246         __add_hash_entry(hash, entry);
1247 
1248         return 0;
1249 }
1250 
1251 static void
1252 free_hash_entry(struct ftrace_hash *hash,
1253                   struct ftrace_func_entry *entry)
1254 {
1255         hlist_del(&entry->hlist);
1256         kfree(entry);
1257         hash->count--;
1258 }
1259 
1260 static void
1261 remove_hash_entry(struct ftrace_hash *hash,
1262                   struct ftrace_func_entry *entry)
1263 {
1264         hlist_del_rcu(&entry->hlist);
1265         hash->count--;
1266 }
1267 
1268 static void ftrace_hash_clear(struct ftrace_hash *hash)
1269 {
1270         struct hlist_head *hhd;
1271         struct hlist_node *tn;
1272         struct ftrace_func_entry *entry;
1273         int size = 1 << hash->size_bits;
1274         int i;
1275 
1276         if (!hash->count)
1277                 return;
1278 
1279         for (i = 0; i < size; i++) {
1280                 hhd = &hash->buckets[i];
1281                 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1282                         free_hash_entry(hash, entry);
1283         }
1284         FTRACE_WARN_ON(hash->count);
1285 }
1286 
1287 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1288 {
1289         list_del(&ftrace_mod->list);
1290         kfree(ftrace_mod->module);
1291         kfree(ftrace_mod->func);
1292         kfree(ftrace_mod);
1293 }
1294 
1295 static void clear_ftrace_mod_list(struct list_head *head)
1296 {
1297         struct ftrace_mod_load *p, *n;
1298 
1299         /* stack tracer isn't supported yet */
1300         if (!head)
1301                 return;
1302 
1303         mutex_lock(&ftrace_lock);
1304         list_for_each_entry_safe(p, n, head, list)
1305                 free_ftrace_mod(p);
1306         mutex_unlock(&ftrace_lock);
1307 }
1308 
1309 static void free_ftrace_hash(struct ftrace_hash *hash)
1310 {
1311         if (!hash || hash == EMPTY_HASH)
1312                 return;
1313         ftrace_hash_clear(hash);
1314         kfree(hash->buckets);
1315         kfree(hash);
1316 }
1317 
1318 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1319 {
1320         struct ftrace_hash *hash;
1321 
1322         hash = container_of(rcu, struct ftrace_hash, rcu);
1323         free_ftrace_hash(hash);
1324 }
1325 
1326 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1327 {
1328         if (!hash || hash == EMPTY_HASH)
1329                 return;
1330         call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1331 }
1332 
1333 void ftrace_free_filter(struct ftrace_ops *ops)
1334 {
1335         ftrace_ops_init(ops);
1336         free_ftrace_hash(ops->func_hash->filter_hash);
1337         free_ftrace_hash(ops->func_hash->notrace_hash);
1338 }
1339 
1340 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1341 {
1342         struct ftrace_hash *hash;
1343         int size;
1344 
1345         hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1346         if (!hash)
1347                 return NULL;
1348 
1349         size = 1 << size_bits;
1350         hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1351 
1352         if (!hash->buckets) {
1353                 kfree(hash);
1354                 return NULL;
1355         }
1356 
1357         hash->size_bits = size_bits;
1358 
1359         return hash;
1360 }
1361 
1362 
1363 static int ftrace_add_mod(struct trace_array *tr,
1364                           const char *func, const char *module,
1365                           int enable)
1366 {
1367         struct ftrace_mod_load *ftrace_mod;
1368         struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1369 
1370         ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1371         if (!ftrace_mod)
1372                 return -ENOMEM;
1373 
1374         ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1375         ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1376         ftrace_mod->enable = enable;
1377 
1378         if (!ftrace_mod->func || !ftrace_mod->module)
1379                 goto out_free;
1380 
1381         list_add(&ftrace_mod->list, mod_head);
1382 
1383         return 0;
1384 
1385  out_free:
1386         free_ftrace_mod(ftrace_mod);
1387 
1388         return -ENOMEM;
1389 }
1390 
1391 static struct ftrace_hash *
1392 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1393 {
1394         struct ftrace_func_entry *entry;
1395         struct ftrace_hash *new_hash;
1396         int size;
1397         int ret;
1398         int i;
1399 
1400         new_hash = alloc_ftrace_hash(size_bits);
1401         if (!new_hash)
1402                 return NULL;
1403 
1404         if (hash)
1405                 new_hash->flags = hash->flags;
1406 
1407         /* Empty hash? */
1408         if (ftrace_hash_empty(hash))
1409                 return new_hash;
1410 
1411         size = 1 << hash->size_bits;
1412         for (i = 0; i < size; i++) {
1413                 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1414                         ret = add_hash_entry(new_hash, entry->ip);
1415                         if (ret < 0)
1416                                 goto free_hash;
1417                 }
1418         }
1419 
1420         FTRACE_WARN_ON(new_hash->count != hash->count);
1421 
1422         return new_hash;
1423 
1424  free_hash:
1425         free_ftrace_hash(new_hash);
1426         return NULL;
1427 }
1428 
1429 static void
1430 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1431 static void
1432 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1433 
1434 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1435                                        struct ftrace_hash *new_hash);
1436 
1437 static struct ftrace_hash *
1438 __ftrace_hash_move(struct ftrace_hash *src)
1439 {
1440         struct ftrace_func_entry *entry;
1441         struct hlist_node *tn;
1442         struct hlist_head *hhd;
1443         struct ftrace_hash *new_hash;
1444         int size = src->count;
1445         int bits = 0;
1446         int i;
1447 
1448         /*
1449          * If the new source is empty, just return the empty_hash.
1450          */
1451         if (ftrace_hash_empty(src))
1452                 return EMPTY_HASH;
1453 
1454         /*
1455          * Make the hash size about 1/2 the # found
1456          */
1457         for (size /= 2; size; size >>= 1)
1458                 bits++;
1459 
1460         /* Don't allocate too much */
1461         if (bits > FTRACE_HASH_MAX_BITS)
1462                 bits = FTRACE_HASH_MAX_BITS;
1463 
1464         new_hash = alloc_ftrace_hash(bits);
1465         if (!new_hash)
1466                 return NULL;
1467 
1468         new_hash->flags = src->flags;
1469 
1470         size = 1 << src->size_bits;
1471         for (i = 0; i < size; i++) {
1472                 hhd = &src->buckets[i];
1473                 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1474                         remove_hash_entry(src, entry);
1475                         __add_hash_entry(new_hash, entry);
1476                 }
1477         }
1478 
1479         return new_hash;
1480 }
1481 
1482 static int
1483 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1484                  struct ftrace_hash **dst, struct ftrace_hash *src)
1485 {
1486         struct ftrace_hash *new_hash;
1487         int ret;
1488 
1489         /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1490         if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1491                 return -EINVAL;
1492 
1493         new_hash = __ftrace_hash_move(src);
1494         if (!new_hash)
1495                 return -ENOMEM;
1496 
1497         /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1498         if (enable) {
1499                 /* IPMODIFY should be updated only when filter_hash updating */
1500                 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1501                 if (ret < 0) {
1502                         free_ftrace_hash(new_hash);
1503                         return ret;
1504                 }
1505         }
1506 
1507         /*
1508          * Remove the current set, update the hash and add
1509          * them back.
1510          */
1511         ftrace_hash_rec_disable_modify(ops, enable);
1512 
1513         rcu_assign_pointer(*dst, new_hash);
1514 
1515         ftrace_hash_rec_enable_modify(ops, enable);
1516 
1517         return 0;
1518 }
1519 
1520 static bool hash_contains_ip(unsigned long ip,
1521                              struct ftrace_ops_hash *hash)
1522 {
1523         /*
1524          * The function record is a match if it exists in the filter
1525          * hash and not in the notrace hash. Note, an emty hash is
1526          * considered a match for the filter hash, but an empty
1527          * notrace hash is considered not in the notrace hash.
1528          */
1529         return (ftrace_hash_empty(hash->filter_hash) ||
1530                 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1531                 (ftrace_hash_empty(hash->notrace_hash) ||
1532                  !__ftrace_lookup_ip(hash->notrace_hash, ip));
1533 }
1534 
1535 /*
1536  * Test the hashes for this ops to see if we want to call
1537  * the ops->func or not.
1538  *
1539  * It's a match if the ip is in the ops->filter_hash or
1540  * the filter_hash does not exist or is empty,
1541  *  AND
1542  * the ip is not in the ops->notrace_hash.
1543  *
1544  * This needs to be called with preemption disabled as
1545  * the hashes are freed with call_rcu_sched().
1546  */
1547 static int
1548 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1549 {
1550         struct ftrace_ops_hash hash;
1551         int ret;
1552 
1553 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1554         /*
1555          * There's a small race when adding ops that the ftrace handler
1556          * that wants regs, may be called without them. We can not
1557          * allow that handler to be called if regs is NULL.
1558          */
1559         if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1560                 return 0;
1561 #endif
1562 
1563         rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1564         rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1565 
1566         if (hash_contains_ip(ip, &hash))
1567                 ret = 1;
1568         else
1569                 ret = 0;
1570 
1571         return ret;
1572 }
1573 
1574 /*
1575  * This is a double for. Do not use 'break' to break out of the loop,
1576  * you must use a goto.
1577  */
1578 #define do_for_each_ftrace_rec(pg, rec)                                 \
1579         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
1580                 int _____i;                                             \
1581                 for (_____i = 0; _____i < pg->index; _____i++) {        \
1582                         rec = &pg->records[_____i];
1583 
1584 #define while_for_each_ftrace_rec()             \
1585                 }                               \
1586         }
1587 
1588 
1589 static int ftrace_cmp_recs(const void *a, const void *b)
1590 {
1591         const struct dyn_ftrace *key = a;
1592         const struct dyn_ftrace *rec = b;
1593 
1594         if (key->flags < rec->ip)
1595                 return -1;
1596         if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1597                 return 1;
1598         return 0;
1599 }
1600 
1601 /**
1602  * ftrace_location_range - return the first address of a traced location
1603  *      if it touches the given ip range
1604  * @start: start of range to search.
1605  * @end: end of range to search (inclusive). @end points to the last byte
1606  *      to check.
1607  *
1608  * Returns rec->ip if the related ftrace location is a least partly within
1609  * the given address range. That is, the first address of the instruction
1610  * that is either a NOP or call to the function tracer. It checks the ftrace
1611  * internal tables to determine if the address belongs or not.
1612  */
1613 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1614 {
1615         struct ftrace_page *pg;
1616         struct dyn_ftrace *rec;
1617         struct dyn_ftrace key;
1618 
1619         key.ip = start;
1620         key.flags = end;        /* overload flags, as it is unsigned long */
1621 
1622         for (pg = ftrace_pages_start; pg; pg = pg->next) {
1623                 if (end < pg->records[0].ip ||
1624                     start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1625                         continue;
1626                 rec = bsearch(&key, pg->records, pg->index,
1627                               sizeof(struct dyn_ftrace),
1628                               ftrace_cmp_recs);
1629                 if (rec)
1630                         return rec->ip;
1631         }
1632 
1633         return 0;
1634 }
1635 
1636 /**
1637  * ftrace_location - return true if the ip giving is a traced location
1638  * @ip: the instruction pointer to check
1639  *
1640  * Returns rec->ip if @ip given is a pointer to a ftrace location.
1641  * That is, the instruction that is either a NOP or call to
1642  * the function tracer. It checks the ftrace internal tables to
1643  * determine if the address belongs or not.
1644  */
1645 unsigned long ftrace_location(unsigned long ip)
1646 {
1647         return ftrace_location_range(ip, ip);
1648 }
1649 
1650 /**
1651  * ftrace_text_reserved - return true if range contains an ftrace location
1652  * @start: start of range to search
1653  * @end: end of range to search (inclusive). @end points to the last byte to check.
1654  *
1655  * Returns 1 if @start and @end contains a ftrace location.
1656  * That is, the instruction that is either a NOP or call to
1657  * the function tracer. It checks the ftrace internal tables to
1658  * determine if the address belongs or not.
1659  */
1660 int ftrace_text_reserved(const void *start, const void *end)
1661 {
1662         unsigned long ret;
1663 
1664         ret = ftrace_location_range((unsigned long)start,
1665                                     (unsigned long)end);
1666 
1667         return (int)!!ret;
1668 }
1669 
1670 /* Test if ops registered to this rec needs regs */
1671 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1672 {
1673         struct ftrace_ops *ops;
1674         bool keep_regs = false;
1675 
1676         for (ops = ftrace_ops_list;
1677              ops != &ftrace_list_end; ops = ops->next) {
1678                 /* pass rec in as regs to have non-NULL val */
1679                 if (ftrace_ops_test(ops, rec->ip, rec)) {
1680                         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1681                                 keep_regs = true;
1682                                 break;
1683                         }
1684                 }
1685         }
1686 
1687         return  keep_regs;
1688 }
1689 
1690 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1691                                      int filter_hash,
1692                                      bool inc)
1693 {
1694         struct ftrace_hash *hash;
1695         struct ftrace_hash *other_hash;
1696         struct ftrace_page *pg;
1697         struct dyn_ftrace *rec;
1698         bool update = false;
1699         int count = 0;
1700         int all = false;
1701 
1702         /* Only update if the ops has been registered */
1703         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1704                 return false;
1705 
1706         /*
1707          * In the filter_hash case:
1708          *   If the count is zero, we update all records.
1709          *   Otherwise we just update the items in the hash.
1710          *
1711          * In the notrace_hash case:
1712          *   We enable the update in the hash.
1713          *   As disabling notrace means enabling the tracing,
1714          *   and enabling notrace means disabling, the inc variable
1715          *   gets inversed.
1716          */
1717         if (filter_hash) {
1718                 hash = ops->func_hash->filter_hash;
1719                 other_hash = ops->func_hash->notrace_hash;
1720                 if (ftrace_hash_empty(hash))
1721                         all = true;
1722         } else {
1723                 inc = !inc;
1724                 hash = ops->func_hash->notrace_hash;
1725                 other_hash = ops->func_hash->filter_hash;
1726                 /*
1727                  * If the notrace hash has no items,
1728                  * then there's nothing to do.
1729                  */
1730                 if (ftrace_hash_empty(hash))
1731                         return false;
1732         }
1733 
1734         do_for_each_ftrace_rec(pg, rec) {
1735                 int in_other_hash = 0;
1736                 int in_hash = 0;
1737                 int match = 0;
1738 
1739                 if (rec->flags & FTRACE_FL_DISABLED)
1740                         continue;
1741 
1742                 if (all) {
1743                         /*
1744                          * Only the filter_hash affects all records.
1745                          * Update if the record is not in the notrace hash.
1746                          */
1747                         if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1748                                 match = 1;
1749                 } else {
1750                         in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1751                         in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1752 
1753                         /*
1754                          * If filter_hash is set, we want to match all functions
1755                          * that are in the hash but not in the other hash.
1756                          *
1757                          * If filter_hash is not set, then we are decrementing.
1758                          * That means we match anything that is in the hash
1759                          * and also in the other_hash. That is, we need to turn
1760                          * off functions in the other hash because they are disabled
1761                          * by this hash.
1762                          */
1763                         if (filter_hash && in_hash && !in_other_hash)
1764                                 match = 1;
1765                         else if (!filter_hash && in_hash &&
1766                                  (in_other_hash || ftrace_hash_empty(other_hash)))
1767                                 match = 1;
1768                 }
1769                 if (!match)
1770                         continue;
1771 
1772                 if (inc) {
1773                         rec->flags++;
1774                         if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1775                                 return false;
1776 
1777                         /*
1778                          * If there's only a single callback registered to a
1779                          * function, and the ops has a trampoline registered
1780                          * for it, then we can call it directly.
1781                          */
1782                         if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1783                                 rec->flags |= FTRACE_FL_TRAMP;
1784                         else
1785                                 /*
1786                                  * If we are adding another function callback
1787                                  * to this function, and the previous had a
1788                                  * custom trampoline in use, then we need to go
1789                                  * back to the default trampoline.
1790                                  */
1791                                 rec->flags &= ~FTRACE_FL_TRAMP;
1792 
1793                         /*
1794                          * If any ops wants regs saved for this function
1795                          * then all ops will get saved regs.
1796                          */
1797                         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1798                                 rec->flags |= FTRACE_FL_REGS;
1799                 } else {
1800                         if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1801                                 return false;
1802                         rec->flags--;
1803 
1804                         /*
1805                          * If the rec had REGS enabled and the ops that is
1806                          * being removed had REGS set, then see if there is
1807                          * still any ops for this record that wants regs.
1808                          * If not, we can stop recording them.
1809                          */
1810                         if (ftrace_rec_count(rec) > 0 &&
1811                             rec->flags & FTRACE_FL_REGS &&
1812                             ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1813                                 if (!test_rec_ops_needs_regs(rec))
1814                                         rec->flags &= ~FTRACE_FL_REGS;
1815                         }
1816 
1817                         /*
1818                          * If the rec had TRAMP enabled, then it needs to
1819                          * be cleared. As TRAMP can only be enabled iff
1820                          * there is only a single ops attached to it.
1821                          * In otherwords, always disable it on decrementing.
1822                          * In the future, we may set it if rec count is
1823                          * decremented to one, and the ops that is left
1824                          * has a trampoline.
1825                          */
1826                         rec->flags &= ~FTRACE_FL_TRAMP;
1827 
1828                         /*
1829                          * flags will be cleared in ftrace_check_record()
1830                          * if rec count is zero.
1831                          */
1832                 }
1833                 count++;
1834 
1835                 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1836                 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
1837 
1838                 /* Shortcut, if we handled all records, we are done. */
1839                 if (!all && count == hash->count)
1840                         return update;
1841         } while_for_each_ftrace_rec();
1842 
1843         return update;
1844 }
1845 
1846 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1847                                     int filter_hash)
1848 {
1849         return __ftrace_hash_rec_update(ops, filter_hash, 0);
1850 }
1851 
1852 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1853                                    int filter_hash)
1854 {
1855         return __ftrace_hash_rec_update(ops, filter_hash, 1);
1856 }
1857 
1858 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1859                                           int filter_hash, int inc)
1860 {
1861         struct ftrace_ops *op;
1862 
1863         __ftrace_hash_rec_update(ops, filter_hash, inc);
1864 
1865         if (ops->func_hash != &global_ops.local_hash)
1866                 return;
1867 
1868         /*
1869          * If the ops shares the global_ops hash, then we need to update
1870          * all ops that are enabled and use this hash.
1871          */
1872         do_for_each_ftrace_op(op, ftrace_ops_list) {
1873                 /* Already done */
1874                 if (op == ops)
1875                         continue;
1876                 if (op->func_hash == &global_ops.local_hash)
1877                         __ftrace_hash_rec_update(op, filter_hash, inc);
1878         } while_for_each_ftrace_op(op);
1879 }
1880 
1881 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1882                                            int filter_hash)
1883 {
1884         ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1885 }
1886 
1887 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1888                                           int filter_hash)
1889 {
1890         ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1891 }
1892 
1893 /*
1894  * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1895  * or no-needed to update, -EBUSY if it detects a conflict of the flag
1896  * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1897  * Note that old_hash and new_hash has below meanings
1898  *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1899  *  - If the hash is EMPTY_HASH, it hits nothing
1900  *  - Anything else hits the recs which match the hash entries.
1901  */
1902 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1903                                          struct ftrace_hash *old_hash,
1904                                          struct ftrace_hash *new_hash)
1905 {
1906         struct ftrace_page *pg;
1907         struct dyn_ftrace *rec, *end = NULL;
1908         int in_old, in_new;
1909 
1910         /* Only update if the ops has been registered */
1911         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1912                 return 0;
1913 
1914         if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1915                 return 0;
1916 
1917         /*
1918          * Since the IPMODIFY is a very address sensitive action, we do not
1919          * allow ftrace_ops to set all functions to new hash.
1920          */
1921         if (!new_hash || !old_hash)
1922                 return -EINVAL;
1923 
1924         /* Update rec->flags */
1925         do_for_each_ftrace_rec(pg, rec) {
1926 
1927                 if (rec->flags & FTRACE_FL_DISABLED)
1928                         continue;
1929 
1930                 /* We need to update only differences of filter_hash */
1931                 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1932                 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1933                 if (in_old == in_new)
1934                         continue;
1935 
1936                 if (in_new) {
1937                         /* New entries must ensure no others are using it */
1938                         if (rec->flags & FTRACE_FL_IPMODIFY)
1939                                 goto rollback;
1940                         rec->flags |= FTRACE_FL_IPMODIFY;
1941                 } else /* Removed entry */
1942                         rec->flags &= ~FTRACE_FL_IPMODIFY;
1943         } while_for_each_ftrace_rec();
1944 
1945         return 0;
1946 
1947 rollback:
1948         end = rec;
1949 
1950         /* Roll back what we did above */
1951         do_for_each_ftrace_rec(pg, rec) {
1952 
1953                 if (rec->flags & FTRACE_FL_DISABLED)
1954                         continue;
1955 
1956                 if (rec == end)
1957                         goto err_out;
1958 
1959                 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1960                 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1961                 if (in_old == in_new)
1962                         continue;
1963 
1964                 if (in_new)
1965                         rec->flags &= ~FTRACE_FL_IPMODIFY;
1966                 else
1967                         rec->flags |= FTRACE_FL_IPMODIFY;
1968         } while_for_each_ftrace_rec();
1969 
1970 err_out:
1971         return -EBUSY;
1972 }
1973 
1974 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1975 {
1976         struct ftrace_hash *hash = ops->func_hash->filter_hash;
1977 
1978         if (ftrace_hash_empty(hash))
1979                 hash = NULL;
1980 
1981         return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1982 }
1983 
1984 /* Disabling always succeeds */
1985 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1986 {
1987         struct ftrace_hash *hash = ops->func_hash->filter_hash;
1988 
1989         if (ftrace_hash_empty(hash))
1990                 hash = NULL;
1991 
1992         __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1993 }
1994 
1995 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1996                                        struct ftrace_hash *new_hash)
1997 {
1998         struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1999 
2000         if (ftrace_hash_empty(old_hash))
2001                 old_hash = NULL;
2002 
2003         if (ftrace_hash_empty(new_hash))
2004                 new_hash = NULL;
2005 
2006         return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2007 }
2008 
2009 static void print_ip_ins(const char *fmt, const unsigned char *p)
2010 {
2011         int i;
2012 
2013         printk(KERN_CONT "%s", fmt);
2014 
2015         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
2016                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
2017 }
2018 
2019 static struct ftrace_ops *
2020 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
2021 static struct ftrace_ops *
2022 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
2023 
2024 enum ftrace_bug_type ftrace_bug_type;
2025 const void *ftrace_expected;
2026 
2027 static void print_bug_type(void)
2028 {
2029         switch (ftrace_bug_type) {
2030         case FTRACE_BUG_UNKNOWN:
2031                 break;
2032         case FTRACE_BUG_INIT:
2033                 pr_info("Initializing ftrace call sites\n");
2034                 break;
2035         case FTRACE_BUG_NOP:
2036                 pr_info("Setting ftrace call site to NOP\n");
2037                 break;
2038         case FTRACE_BUG_CALL:
2039                 pr_info("Setting ftrace call site to call ftrace function\n");
2040                 break;
2041         case FTRACE_BUG_UPDATE:
2042                 pr_info("Updating ftrace call site to call a different ftrace function\n");
2043                 break;
2044         }
2045 }
2046 
2047 /**
2048  * ftrace_bug - report and shutdown function tracer
2049  * @failed: The failed type (EFAULT, EINVAL, EPERM)
2050  * @rec: The record that failed
2051  *
2052  * The arch code that enables or disables the function tracing
2053  * can call ftrace_bug() when it has detected a problem in
2054  * modifying the code. @failed should be one of either:
2055  * EFAULT - if the problem happens on reading the @ip address
2056  * EINVAL - if what is read at @ip is not what was expected
2057  * EPERM - if the problem happens on writting to the @ip address
2058  */
2059 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2060 {
2061         unsigned long ip = rec ? rec->ip : 0;
2062 
2063         switch (failed) {
2064         case -EFAULT:
2065                 FTRACE_WARN_ON_ONCE(1);
2066                 pr_info("ftrace faulted on modifying ");
2067                 print_ip_sym(ip);
2068                 break;
2069         case -EINVAL:
2070                 FTRACE_WARN_ON_ONCE(1);
2071                 pr_info("ftrace failed to modify ");
2072                 print_ip_sym(ip);
2073                 print_ip_ins(" actual:   ", (unsigned char *)ip);
2074                 pr_cont("\n");
2075                 if (ftrace_expected) {
2076                         print_ip_ins(" expected: ", ftrace_expected);
2077                         pr_cont("\n");
2078                 }
2079                 break;
2080         case -EPERM:
2081                 FTRACE_WARN_ON_ONCE(1);
2082                 pr_info("ftrace faulted on writing ");
2083                 print_ip_sym(ip);
2084                 break;
2085         default:
2086                 FTRACE_WARN_ON_ONCE(1);
2087                 pr_info("ftrace faulted on unknown error ");
2088                 print_ip_sym(ip);
2089         }
2090         print_bug_type();
2091         if (rec) {
2092                 struct ftrace_ops *ops = NULL;
2093 
2094                 pr_info("ftrace record flags: %lx\n", rec->flags);
2095                 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2096                         rec->flags & FTRACE_FL_REGS ? " R" : "  ");
2097                 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2098                         ops = ftrace_find_tramp_ops_any(rec);
2099                         if (ops) {
2100                                 do {
2101                                         pr_cont("\ttramp: %pS (%pS)",
2102                                                 (void *)ops->trampoline,
2103                                                 (void *)ops->func);
2104                                         ops = ftrace_find_tramp_ops_next(rec, ops);
2105                                 } while (ops);
2106                         } else
2107                                 pr_cont("\ttramp: ERROR!");
2108 
2109                 }
2110                 ip = ftrace_get_addr_curr(rec);
2111                 pr_cont("\n expected tramp: %lx\n", ip);
2112         }
2113 }
2114 
2115 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
2116 {
2117         unsigned long flag = 0UL;
2118 
2119         ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2120 
2121         if (rec->flags & FTRACE_FL_DISABLED)
2122                 return FTRACE_UPDATE_IGNORE;
2123 
2124         /*
2125          * If we are updating calls:
2126          *
2127          *   If the record has a ref count, then we need to enable it
2128          *   because someone is using it.
2129          *
2130          *   Otherwise we make sure its disabled.
2131          *
2132          * If we are disabling calls, then disable all records that
2133          * are enabled.
2134          */
2135         if (enable && ftrace_rec_count(rec))
2136                 flag = FTRACE_FL_ENABLED;
2137 
2138         /*
2139          * If enabling and the REGS flag does not match the REGS_EN, or
2140          * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2141          * this record. Set flags to fail the compare against ENABLED.
2142          */
2143         if (flag) {
2144                 if (!(rec->flags & FTRACE_FL_REGS) != 
2145                     !(rec->flags & FTRACE_FL_REGS_EN))
2146                         flag |= FTRACE_FL_REGS;
2147 
2148                 if (!(rec->flags & FTRACE_FL_TRAMP) != 
2149                     !(rec->flags & FTRACE_FL_TRAMP_EN))
2150                         flag |= FTRACE_FL_TRAMP;
2151         }
2152 
2153         /* If the state of this record hasn't changed, then do nothing */
2154         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2155                 return FTRACE_UPDATE_IGNORE;
2156 
2157         if (flag) {
2158                 /* Save off if rec is being enabled (for return value) */
2159                 flag ^= rec->flags & FTRACE_FL_ENABLED;
2160 
2161                 if (update) {
2162                         rec->flags |= FTRACE_FL_ENABLED;
2163                         if (flag & FTRACE_FL_REGS) {
2164                                 if (rec->flags & FTRACE_FL_REGS)
2165                                         rec->flags |= FTRACE_FL_REGS_EN;
2166                                 else
2167                                         rec->flags &= ~FTRACE_FL_REGS_EN;
2168                         }
2169                         if (flag & FTRACE_FL_TRAMP) {
2170                                 if (rec->flags & FTRACE_FL_TRAMP)
2171                                         rec->flags |= FTRACE_FL_TRAMP_EN;
2172                                 else
2173                                         rec->flags &= ~FTRACE_FL_TRAMP_EN;
2174                         }
2175                 }
2176 
2177                 /*
2178                  * If this record is being updated from a nop, then
2179                  *   return UPDATE_MAKE_CALL.
2180                  * Otherwise,
2181                  *   return UPDATE_MODIFY_CALL to tell the caller to convert
2182                  *   from the save regs, to a non-save regs function or
2183                  *   vice versa, or from a trampoline call.
2184                  */
2185                 if (flag & FTRACE_FL_ENABLED) {
2186                         ftrace_bug_type = FTRACE_BUG_CALL;
2187                         return FTRACE_UPDATE_MAKE_CALL;
2188                 }
2189 
2190                 ftrace_bug_type = FTRACE_BUG_UPDATE;
2191                 return FTRACE_UPDATE_MODIFY_CALL;
2192         }
2193 
2194         if (update) {
2195                 /* If there's no more users, clear all flags */
2196                 if (!ftrace_rec_count(rec))
2197                         rec->flags = 0;
2198                 else
2199                         /*
2200                          * Just disable the record, but keep the ops TRAMP
2201                          * and REGS states. The _EN flags must be disabled though.
2202                          */
2203                         rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2204                                         FTRACE_FL_REGS_EN);
2205         }
2206 
2207         ftrace_bug_type = FTRACE_BUG_NOP;
2208         return FTRACE_UPDATE_MAKE_NOP;
2209 }
2210 
2211 /**
2212  * ftrace_update_record, set a record that now is tracing or not
2213  * @rec: the record to update
2214  * @enable: set to 1 if the record is tracing, zero to force disable
2215  *
2216  * The records that represent all functions that can be traced need
2217  * to be updated when tracing has been enabled.
2218  */
2219 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
2220 {
2221         return ftrace_check_record(rec, enable, 1);
2222 }
2223 
2224 /**
2225  * ftrace_test_record, check if the record has been enabled or not
2226  * @rec: the record to test
2227  * @enable: set to 1 to check if enabled, 0 if it is disabled
2228  *
2229  * The arch code may need to test if a record is already set to
2230  * tracing to determine how to modify the function code that it
2231  * represents.
2232  */
2233 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
2234 {
2235         return ftrace_check_record(rec, enable, 0);
2236 }
2237 
2238 static struct ftrace_ops *
2239 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2240 {
2241         struct ftrace_ops *op;
2242         unsigned long ip = rec->ip;
2243 
2244         do_for_each_ftrace_op(op, ftrace_ops_list) {
2245 
2246                 if (!op->trampoline)
2247                         continue;
2248 
2249                 if (hash_contains_ip(ip, op->func_hash))
2250                         return op;
2251         } while_for_each_ftrace_op(op);
2252 
2253         return NULL;
2254 }
2255 
2256 static struct ftrace_ops *
2257 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2258                            struct ftrace_ops *op)
2259 {
2260         unsigned long ip = rec->ip;
2261 
2262         while_for_each_ftrace_op(op) {
2263 
2264                 if (!op->trampoline)
2265                         continue;
2266 
2267                 if (hash_contains_ip(ip, op->func_hash))
2268                         return op;
2269         } 
2270 
2271         return NULL;
2272 }
2273 
2274 static struct ftrace_ops *
2275 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2276 {
2277         struct ftrace_ops *op;
2278         unsigned long ip = rec->ip;
2279 
2280         /*
2281          * Need to check removed ops first.
2282          * If they are being removed, and this rec has a tramp,
2283          * and this rec is in the ops list, then it would be the
2284          * one with the tramp.
2285          */
2286         if (removed_ops) {
2287                 if (hash_contains_ip(ip, &removed_ops->old_hash))
2288                         return removed_ops;
2289         }
2290 
2291         /*
2292          * Need to find the current trampoline for a rec.
2293          * Now, a trampoline is only attached to a rec if there
2294          * was a single 'ops' attached to it. But this can be called
2295          * when we are adding another op to the rec or removing the
2296          * current one. Thus, if the op is being added, we can
2297          * ignore it because it hasn't attached itself to the rec
2298          * yet.
2299          *
2300          * If an ops is being modified (hooking to different functions)
2301          * then we don't care about the new functions that are being
2302          * added, just the old ones (that are probably being removed).
2303          *
2304          * If we are adding an ops to a function that already is using
2305          * a trampoline, it needs to be removed (trampolines are only
2306          * for single ops connected), then an ops that is not being
2307          * modified also needs to be checked.
2308          */
2309         do_for_each_ftrace_op(op, ftrace_ops_list) {
2310 
2311                 if (!op->trampoline)
2312                         continue;
2313 
2314                 /*
2315                  * If the ops is being added, it hasn't gotten to
2316                  * the point to be removed from this tree yet.
2317                  */
2318                 if (op->flags & FTRACE_OPS_FL_ADDING)
2319                         continue;
2320 
2321 
2322                 /*
2323                  * If the ops is being modified and is in the old
2324                  * hash, then it is probably being removed from this
2325                  * function.
2326                  */
2327                 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2328                     hash_contains_ip(ip, &op->old_hash))
2329                         return op;
2330                 /*
2331                  * If the ops is not being added or modified, and it's
2332                  * in its normal filter hash, then this must be the one
2333                  * we want!
2334                  */
2335                 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2336                     hash_contains_ip(ip, op->func_hash))
2337                         return op;
2338 
2339         } while_for_each_ftrace_op(op);
2340 
2341         return NULL;
2342 }
2343 
2344 static struct ftrace_ops *
2345 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2346 {
2347         struct ftrace_ops *op;
2348         unsigned long ip = rec->ip;
2349 
2350         do_for_each_ftrace_op(op, ftrace_ops_list) {
2351                 /* pass rec in as regs to have non-NULL val */
2352                 if (hash_contains_ip(ip, op->func_hash))
2353                         return op;
2354         } while_for_each_ftrace_op(op);
2355 
2356         return NULL;
2357 }
2358 
2359 /**
2360  * ftrace_get_addr_new - Get the call address to set to
2361  * @rec:  The ftrace record descriptor
2362  *
2363  * If the record has the FTRACE_FL_REGS set, that means that it
2364  * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2365  * is not not set, then it wants to convert to the normal callback.
2366  *
2367  * Returns the address of the trampoline to set to
2368  */
2369 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2370 {
2371         struct ftrace_ops *ops;
2372 
2373         /* Trampolines take precedence over regs */
2374         if (rec->flags & FTRACE_FL_TRAMP) {
2375                 ops = ftrace_find_tramp_ops_new(rec);
2376                 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2377                         pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2378                                 (void *)rec->ip, (void *)rec->ip, rec->flags);
2379                         /* Ftrace is shutting down, return anything */
2380                         return (unsigned long)FTRACE_ADDR;
2381                 }
2382                 return ops->trampoline;
2383         }
2384 
2385         if (rec->flags & FTRACE_FL_REGS)
2386                 return (unsigned long)FTRACE_REGS_ADDR;
2387         else
2388                 return (unsigned long)FTRACE_ADDR;
2389 }
2390 
2391 /**
2392  * ftrace_get_addr_curr - Get the call address that is already there
2393  * @rec:  The ftrace record descriptor
2394  *
2395  * The FTRACE_FL_REGS_EN is set when the record already points to
2396  * a function that saves all the regs. Basically the '_EN' version
2397  * represents the current state of the function.
2398  *
2399  * Returns the address of the trampoline that is currently being called
2400  */
2401 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2402 {
2403         struct ftrace_ops *ops;
2404 
2405         /* Trampolines take precedence over regs */
2406         if (rec->flags & FTRACE_FL_TRAMP_EN) {
2407                 ops = ftrace_find_tramp_ops_curr(rec);
2408                 if (FTRACE_WARN_ON(!ops)) {
2409                         pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2410                                 (void *)rec->ip, (void *)rec->ip);
2411                         /* Ftrace is shutting down, return anything */
2412                         return (unsigned long)FTRACE_ADDR;
2413                 }
2414                 return ops->trampoline;
2415         }
2416 
2417         if (rec->flags & FTRACE_FL_REGS_EN)
2418                 return (unsigned long)FTRACE_REGS_ADDR;
2419         else
2420                 return (unsigned long)FTRACE_ADDR;
2421 }
2422 
2423 static int
2424 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2425 {
2426         unsigned long ftrace_old_addr;
2427         unsigned long ftrace_addr;
2428         int ret;
2429 
2430         ftrace_addr = ftrace_get_addr_new(rec);
2431 
2432         /* This needs to be done before we call ftrace_update_record */
2433         ftrace_old_addr = ftrace_get_addr_curr(rec);
2434 
2435         ret = ftrace_update_record(rec, enable);
2436 
2437         ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2438 
2439         switch (ret) {
2440         case FTRACE_UPDATE_IGNORE:
2441                 return 0;
2442 
2443         case FTRACE_UPDATE_MAKE_CALL:
2444                 ftrace_bug_type = FTRACE_BUG_CALL;
2445                 return ftrace_make_call(rec, ftrace_addr);
2446 
2447         case FTRACE_UPDATE_MAKE_NOP:
2448                 ftrace_bug_type = FTRACE_BUG_NOP;
2449                 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2450 
2451         case FTRACE_UPDATE_MODIFY_CALL:
2452                 ftrace_bug_type = FTRACE_BUG_UPDATE;
2453                 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2454         }
2455 
2456         return -1; /* unknow ftrace bug */
2457 }
2458 
2459 void __weak ftrace_replace_code(int enable)
2460 {
2461         struct dyn_ftrace *rec;
2462         struct ftrace_page *pg;
2463         int failed;
2464 
2465         if (unlikely(ftrace_disabled))
2466                 return;
2467 
2468         do_for_each_ftrace_rec(pg, rec) {
2469 
2470                 if (rec->flags & FTRACE_FL_DISABLED)
2471                         continue;
2472 
2473                 failed = __ftrace_replace_code(rec, enable);
2474                 if (failed) {
2475                         ftrace_bug(failed, rec);
2476                         /* Stop processing */
2477                         return;
2478                 }
2479         } while_for_each_ftrace_rec();
2480 }
2481 
2482 struct ftrace_rec_iter {
2483         struct ftrace_page      *pg;
2484         int                     index;
2485 };
2486 
2487 /**
2488  * ftrace_rec_iter_start, start up iterating over traced functions
2489  *
2490  * Returns an iterator handle that is used to iterate over all
2491  * the records that represent address locations where functions
2492  * are traced.
2493  *
2494  * May return NULL if no records are available.
2495  */
2496 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2497 {
2498         /*
2499          * We only use a single iterator.
2500          * Protected by the ftrace_lock mutex.
2501          */
2502         static struct ftrace_rec_iter ftrace_rec_iter;
2503         struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2504 
2505         iter->pg = ftrace_pages_start;
2506         iter->index = 0;
2507 
2508         /* Could have empty pages */
2509         while (iter->pg && !iter->pg->index)
2510                 iter->pg = iter->pg->next;
2511 
2512         if (!iter->pg)
2513                 return NULL;
2514 
2515         return iter;
2516 }
2517 
2518 /**
2519  * ftrace_rec_iter_next, get the next record to process.
2520  * @iter: The handle to the iterator.
2521  *
2522  * Returns the next iterator after the given iterator @iter.
2523  */
2524 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2525 {
2526         iter->index++;
2527 
2528         if (iter->index >= iter->pg->index) {
2529                 iter->pg = iter->pg->next;
2530                 iter->index = 0;
2531 
2532                 /* Could have empty pages */
2533                 while (iter->pg && !iter->pg->index)
2534                         iter->pg = iter->pg->next;
2535         }
2536 
2537         if (!iter->pg)
2538                 return NULL;
2539 
2540         return iter;
2541 }
2542 
2543 /**
2544  * ftrace_rec_iter_record, get the record at the iterator location
2545  * @iter: The current iterator location
2546  *
2547  * Returns the record that the current @iter is at.
2548  */
2549 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2550 {
2551         return &iter->pg->records[iter->index];
2552 }
2553 
2554 static int
2555 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2556 {
2557         int ret;
2558 
2559         if (unlikely(ftrace_disabled))
2560                 return 0;
2561 
2562         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2563         if (ret) {
2564                 ftrace_bug_type = FTRACE_BUG_INIT;
2565                 ftrace_bug(ret, rec);
2566                 return 0;
2567         }
2568         return 1;
2569 }
2570 
2571 /*
2572  * archs can override this function if they must do something
2573  * before the modifying code is performed.
2574  */
2575 int __weak ftrace_arch_code_modify_prepare(void)
2576 {
2577         return 0;
2578 }
2579 
2580 /*
2581  * archs can override this function if they must do something
2582  * after the modifying code is performed.
2583  */
2584 int __weak ftrace_arch_code_modify_post_process(void)
2585 {
2586         return 0;
2587 }
2588 
2589 void ftrace_modify_all_code(int command)
2590 {
2591         int update = command & FTRACE_UPDATE_TRACE_FUNC;
2592         int err = 0;
2593 
2594         /*
2595          * If the ftrace_caller calls a ftrace_ops func directly,
2596          * we need to make sure that it only traces functions it
2597          * expects to trace. When doing the switch of functions,
2598          * we need to update to the ftrace_ops_list_func first
2599          * before the transition between old and new calls are set,
2600          * as the ftrace_ops_list_func will check the ops hashes
2601          * to make sure the ops are having the right functions
2602          * traced.
2603          */
2604         if (update) {
2605                 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2606                 if (FTRACE_WARN_ON(err))
2607                         return;
2608         }
2609 
2610         if (command & FTRACE_UPDATE_CALLS)
2611                 ftrace_replace_code(1);
2612         else if (command & FTRACE_DISABLE_CALLS)
2613                 ftrace_replace_code(0);
2614 
2615         if (update && ftrace_trace_function != ftrace_ops_list_func) {
2616                 function_trace_op = set_function_trace_op;
2617                 smp_wmb();
2618                 /* If irqs are disabled, we are in stop machine */
2619                 if (!irqs_disabled())
2620                         smp_call_function(ftrace_sync_ipi, NULL, 1);
2621                 err = ftrace_update_ftrace_func(ftrace_trace_function);
2622                 if (FTRACE_WARN_ON(err))
2623                         return;
2624         }
2625 
2626         if (command & FTRACE_START_FUNC_RET)
2627                 err = ftrace_enable_ftrace_graph_caller();
2628         else if (command & FTRACE_STOP_FUNC_RET)
2629                 err = ftrace_disable_ftrace_graph_caller();
2630         FTRACE_WARN_ON(err);
2631 }
2632 
2633 static int __ftrace_modify_code(void *data)
2634 {
2635         int *command = data;
2636 
2637         ftrace_modify_all_code(*command);
2638 
2639         return 0;
2640 }
2641 
2642 /**
2643  * ftrace_run_stop_machine, go back to the stop machine method
2644  * @command: The command to tell ftrace what to do
2645  *
2646  * If an arch needs to fall back to the stop machine method, the
2647  * it can call this function.
2648  */
2649 void ftrace_run_stop_machine(int command)
2650 {
2651         stop_machine(__ftrace_modify_code, &command, NULL);
2652 }
2653 
2654 /**
2655  * arch_ftrace_update_code, modify the code to trace or not trace
2656  * @command: The command that needs to be done
2657  *
2658  * Archs can override this function if it does not need to
2659  * run stop_machine() to modify code.
2660  */
2661 void __weak arch_ftrace_update_code(int command)
2662 {
2663         ftrace_run_stop_machine(command);
2664 }
2665 
2666 static void ftrace_run_update_code(int command)
2667 {
2668         int ret;
2669 
2670         ret = ftrace_arch_code_modify_prepare();
2671         FTRACE_WARN_ON(ret);
2672         if (ret)
2673                 return;
2674 
2675         /*
2676          * By default we use stop_machine() to modify the code.
2677          * But archs can do what ever they want as long as it
2678          * is safe. The stop_machine() is the safest, but also
2679          * produces the most overhead.
2680          */
2681         arch_ftrace_update_code(command);
2682 
2683         ret = ftrace_arch_code_modify_post_process();
2684         FTRACE_WARN_ON(ret);
2685 }
2686 
2687 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2688                                    struct ftrace_ops_hash *old_hash)
2689 {
2690         ops->flags |= FTRACE_OPS_FL_MODIFYING;
2691         ops->old_hash.filter_hash = old_hash->filter_hash;
2692         ops->old_hash.notrace_hash = old_hash->notrace_hash;
2693         ftrace_run_update_code(command);
2694         ops->old_hash.filter_hash = NULL;
2695         ops->old_hash.notrace_hash = NULL;
2696         ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2697 }
2698 
2699 static ftrace_func_t saved_ftrace_func;
2700 static int ftrace_start_up;
2701 
2702 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2703 {
2704 }
2705 
2706 static void ftrace_startup_enable(int command)
2707 {
2708         if (saved_ftrace_func != ftrace_trace_function) {
2709                 saved_ftrace_func = ftrace_trace_function;
2710                 command |= FTRACE_UPDATE_TRACE_FUNC;
2711         }
2712 
2713         if (!command || !ftrace_enabled)
2714                 return;
2715 
2716         ftrace_run_update_code(command);
2717 }
2718 
2719 static void ftrace_startup_all(int command)
2720 {
2721         update_all_ops = true;
2722         ftrace_startup_enable(command);
2723         update_all_ops = false;
2724 }
2725 
2726 static int ftrace_startup(struct ftrace_ops *ops, int command)
2727 {
2728         int ret;
2729 
2730         if (unlikely(ftrace_disabled))
2731                 return -ENODEV;
2732 
2733         ret = __register_ftrace_function(ops);
2734         if (ret)
2735                 return ret;
2736 
2737         ftrace_start_up++;
2738 
2739         /*
2740          * Note that ftrace probes uses this to start up
2741          * and modify functions it will probe. But we still
2742          * set the ADDING flag for modification, as probes
2743          * do not have trampolines. If they add them in the
2744          * future, then the probes will need to distinguish
2745          * between adding and updating probes.
2746          */
2747         ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2748 
2749         ret = ftrace_hash_ipmodify_enable(ops);
2750         if (ret < 0) {
2751                 /* Rollback registration process */
2752                 __unregister_ftrace_function(ops);
2753                 ftrace_start_up--;
2754                 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2755                 return ret;
2756         }
2757 
2758         if (ftrace_hash_rec_enable(ops, 1))
2759                 command |= FTRACE_UPDATE_CALLS;
2760 
2761         ftrace_startup_enable(command);
2762 
2763         ops->flags &= ~FTRACE_OPS_FL_ADDING;
2764 
2765         return 0;
2766 }
2767 
2768 static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2769 {
2770         int ret;
2771 
2772         if (unlikely(ftrace_disabled))
2773                 return -ENODEV;
2774 
2775         ret = __unregister_ftrace_function(ops);
2776         if (ret)
2777                 return ret;
2778 
2779         ftrace_start_up--;
2780         /*
2781          * Just warn in case of unbalance, no need to kill ftrace, it's not
2782          * critical but the ftrace_call callers may be never nopped again after
2783          * further ftrace uses.
2784          */
2785         WARN_ON_ONCE(ftrace_start_up < 0);
2786 
2787         /* Disabling ipmodify never fails */
2788         ftrace_hash_ipmodify_disable(ops);
2789 
2790         if (ftrace_hash_rec_disable(ops, 1))
2791                 command |= FTRACE_UPDATE_CALLS;
2792 
2793         ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2794 
2795         if (saved_ftrace_func != ftrace_trace_function) {
2796                 saved_ftrace_func = ftrace_trace_function;
2797                 command |= FTRACE_UPDATE_TRACE_FUNC;
2798         }
2799 
2800         if (!command || !ftrace_enabled) {
2801                 /*
2802                  * If these are dynamic or per_cpu ops, they still
2803                  * need their data freed. Since, function tracing is
2804                  * not currently active, we can just free them
2805                  * without synchronizing all CPUs.
2806                  */
2807                 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2808                         goto free_ops;
2809 
2810                 return 0;
2811         }
2812 
2813         /*
2814          * If the ops uses a trampoline, then it needs to be
2815          * tested first on update.
2816          */
2817         ops->flags |= FTRACE_OPS_FL_REMOVING;
2818         removed_ops = ops;
2819 
2820         /* The trampoline logic checks the old hashes */
2821         ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2822         ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2823 
2824         ftrace_run_update_code(command);
2825 
2826         /*
2827          * If there's no more ops registered with ftrace, run a
2828          * sanity check to make sure all rec flags are cleared.
2829          */
2830         if (rcu_dereference_protected(ftrace_ops_list,
2831                         lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2832                 struct ftrace_page *pg;
2833                 struct dyn_ftrace *rec;
2834 
2835                 do_for_each_ftrace_rec(pg, rec) {
2836                         if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2837                                 pr_warn("  %pS flags:%lx\n",
2838                                         (void *)rec->ip, rec->flags);
2839                 } while_for_each_ftrace_rec();
2840         }
2841 
2842         ops->old_hash.filter_hash = NULL;
2843         ops->old_hash.notrace_hash = NULL;
2844 
2845         removed_ops = NULL;
2846         ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2847 
2848         /*
2849          * Dynamic ops may be freed, we must make sure that all
2850          * callers are done before leaving this function.
2851          * The same goes for freeing the per_cpu data of the per_cpu
2852          * ops.
2853          */
2854         if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2855                 /*
2856                  * We need to do a hard force of sched synchronization.
2857                  * This is because we use preempt_disable() to do RCU, but
2858                  * the function tracers can be called where RCU is not watching
2859                  * (like before user_exit()). We can not rely on the RCU
2860                  * infrastructure to do the synchronization, thus we must do it
2861                  * ourselves.
2862                  */
2863                 schedule_on_each_cpu(ftrace_sync);
2864 
2865                 /*
2866                  * When the kernel is preeptive, tasks can be preempted
2867                  * while on a ftrace trampoline. Just scheduling a task on
2868                  * a CPU is not good enough to flush them. Calling
2869                  * synchornize_rcu_tasks() will wait for those tasks to
2870                  * execute and either schedule voluntarily or enter user space.
2871                  */
2872                 if (IS_ENABLED(CONFIG_PREEMPT))
2873                         synchronize_rcu_tasks();
2874 
2875  free_ops:
2876                 arch_ftrace_trampoline_free(ops);
2877         }
2878 
2879         return 0;
2880 }
2881 
2882 static void ftrace_startup_sysctl(void)
2883 {
2884         int command;
2885 
2886         if (unlikely(ftrace_disabled))
2887                 return;
2888 
2889         /* Force update next time */
2890         saved_ftrace_func = NULL;
2891         /* ftrace_start_up is true if we want ftrace running */
2892         if (ftrace_start_up) {
2893                 command = FTRACE_UPDATE_CALLS;
2894                 if (ftrace_graph_active)
2895                         command |= FTRACE_START_FUNC_RET;
2896                 ftrace_startup_enable(command);
2897         }
2898 }
2899 
2900 static void ftrace_shutdown_sysctl(void)
2901 {
2902         int command;
2903 
2904         if (unlikely(ftrace_disabled))
2905                 return;
2906 
2907         /* ftrace_start_up is true if ftrace is running */
2908         if (ftrace_start_up) {
2909                 command = FTRACE_DISABLE_CALLS;
2910                 if (ftrace_graph_active)
2911                         command |= FTRACE_STOP_FUNC_RET;
2912                 ftrace_run_update_code(command);
2913         }
2914 }
2915 
2916 static u64              ftrace_update_time;
2917 unsigned long           ftrace_update_tot_cnt;
2918 
2919 static inline int ops_traces_mod(struct ftrace_ops *ops)
2920 {
2921         /*
2922          * Filter_hash being empty will default to trace module.
2923          * But notrace hash requires a test of individual module functions.
2924          */
2925         return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2926                 ftrace_hash_empty(ops->func_hash->notrace_hash);
2927 }
2928 
2929 /*
2930  * Check if the current ops references the record.
2931  *
2932  * If the ops traces all functions, then it was already accounted for.
2933  * If the ops does not trace the current record function, skip it.
2934  * If the ops ignores the function via notrace filter, skip it.
2935  */
2936 static inline bool
2937 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2938 {
2939         /* If ops isn't enabled, ignore it */
2940         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2941                 return 0;
2942 
2943         /* If ops traces all then it includes this function */
2944         if (ops_traces_mod(ops))
2945                 return 1;
2946 
2947         /* The function must be in the filter */
2948         if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2949             !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2950                 return 0;
2951 
2952         /* If in notrace hash, we ignore it too */
2953         if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2954                 return 0;
2955 
2956         return 1;
2957 }
2958 
2959 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2960 {
2961         struct ftrace_page *pg;
2962         struct dyn_ftrace *p;
2963         u64 start, stop;
2964         unsigned long update_cnt = 0;
2965         unsigned long rec_flags = 0;
2966         int i;
2967 
2968         start = ftrace_now(raw_smp_processor_id());
2969 
2970         /*
2971          * When a module is loaded, this function is called to convert
2972          * the calls to mcount in its text to nops, and also to create
2973          * an entry in the ftrace data. Now, if ftrace is activated
2974          * after this call, but before the module sets its text to
2975          * read-only, the modification of enabling ftrace can fail if
2976          * the read-only is done while ftrace is converting the calls.
2977          * To prevent this, the module's records are set as disabled
2978          * and will be enabled after the call to set the module's text
2979          * to read-only.
2980          */
2981         if (mod)
2982                 rec_flags |= FTRACE_FL_DISABLED;
2983 
2984         for (pg = new_pgs; pg; pg = pg->next) {
2985 
2986                 for (i = 0; i < pg->index; i++) {
2987 
2988                         /* If something went wrong, bail without enabling anything */
2989                         if (unlikely(ftrace_disabled))
2990                                 return -1;
2991 
2992                         p = &pg->records[i];
2993                         p->flags = rec_flags;
2994 
2995                         /*
2996                          * Do the initial record conversion from mcount jump
2997                          * to the NOP instructions.
2998                          */
2999                         if (!ftrace_code_disable(mod, p))
3000                                 break;
3001 
3002                         update_cnt++;
3003                 }
3004         }
3005 
3006         stop = ftrace_now(raw_smp_processor_id());
3007         ftrace_update_time = stop - start;
3008         ftrace_update_tot_cnt += update_cnt;
3009 
3010         return 0;
3011 }
3012 
3013 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3014 {
3015         int order;
3016         int cnt;
3017 
3018         if (WARN_ON(!count))
3019                 return -EINVAL;
3020 
3021         order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
3022 
3023         /*
3024          * We want to fill as much as possible. No more than a page
3025          * may be empty.
3026          */
3027         while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
3028                 order--;
3029 
3030  again:
3031         pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3032 
3033         if (!pg->records) {
3034                 /* if we can't allocate this size, try something smaller */
3035                 if (!order)
3036                         return -ENOMEM;
3037                 order >>= 1;
3038                 goto again;
3039         }
3040 
3041         cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3042         pg->size = cnt;
3043 
3044         if (cnt > count)
3045                 cnt = count;
3046 
3047         return cnt;
3048 }
3049 
3050 static struct ftrace_page *
3051 ftrace_allocate_pages(unsigned long num_to_init)
3052 {
3053         struct ftrace_page *start_pg;
3054         struct ftrace_page *pg;
3055         int order;
3056         int cnt;
3057 
3058         if (!num_to_init)
3059                 return 0;
3060 
3061         start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3062         if (!pg)
3063                 return NULL;
3064 
3065         /*
3066          * Try to allocate as much as possible in one continues
3067          * location that fills in all of the space. We want to
3068          * waste as little space as possible.
3069          */
3070         for (;;) {
3071                 cnt = ftrace_allocate_records(pg, num_to_init);
3072                 if (cnt < 0)
3073                         goto free_pages;
3074 
3075                 num_to_init -= cnt;
3076                 if (!num_to_init)
3077                         break;
3078 
3079                 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3080                 if (!pg->next)
3081                         goto free_pages;
3082 
3083                 pg = pg->next;
3084         }
3085 
3086         return start_pg;
3087 
3088  free_pages:
3089         pg = start_pg;
3090         while (pg) {
3091                 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3092                 free_pages((unsigned long)pg->records, order);
3093                 start_pg = pg->next;
3094                 kfree(pg);
3095                 pg = start_pg;
3096         }
3097         pr_info("ftrace: FAILED to allocate memory for functions\n");
3098         return NULL;
3099 }
3100 
3101 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3102 
3103 struct ftrace_iterator {
3104         loff_t                          pos;
3105         loff_t                          func_pos;
3106         loff_t                          mod_pos;
3107         struct ftrace_page              *pg;
3108         struct dyn_ftrace               *func;
3109         struct ftrace_func_probe        *probe;
3110         struct ftrace_func_entry        *probe_entry;
3111         struct trace_parser             parser;
3112         struct ftrace_hash              *hash;
3113         struct ftrace_ops               *ops;
3114         struct trace_array              *tr;
3115         struct list_head                *mod_list;
3116         int                             pidx;
3117         int                             idx;
3118         unsigned                        flags;
3119 };
3120 
3121 static void *
3122 t_probe_next(struct seq_file *m, loff_t *pos)
3123 {
3124         struct ftrace_iterator *iter = m->private;
3125         struct trace_array *tr = iter->ops->private;
3126         struct list_head *func_probes;
3127         struct ftrace_hash *hash;
3128         struct list_head *next;
3129         struct hlist_node *hnd = NULL;
3130         struct hlist_head *hhd;
3131         int size;
3132 
3133         (*pos)++;
3134         iter->pos = *pos;
3135 
3136         if (!tr)
3137                 return NULL;
3138 
3139         func_probes = &tr->func_probes;
3140         if (list_empty(func_probes))
3141                 return NULL;
3142 
3143         if (!iter->probe) {
3144                 next = func_probes->next;
3145                 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3146         }
3147 
3148         if (iter->probe_entry)
3149                 hnd = &iter->probe_entry->hlist;
3150 
3151         hash = iter->probe->ops.func_hash->filter_hash;
3152         size = 1 << hash->size_bits;
3153 
3154  retry:
3155         if (iter->pidx >= size) {
3156                 if (iter->probe->list.next == func_probes)
3157                         return NULL;
3158                 next = iter->probe->list.next;
3159                 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3160                 hash = iter->probe->ops.func_hash->filter_hash;
3161                 size = 1 << hash->size_bits;
3162                 iter->pidx = 0;
3163         }
3164 
3165         hhd = &hash->buckets[iter->pidx];
3166 
3167         if (hlist_empty(hhd)) {
3168                 iter->pidx++;
3169                 hnd = NULL;
3170                 goto retry;
3171         }
3172 
3173         if (!hnd)
3174                 hnd = hhd->first;
3175         else {
3176                 hnd = hnd->next;
3177                 if (!hnd) {
3178                         iter->pidx++;
3179                         goto retry;
3180                 }
3181         }
3182 
3183         if (WARN_ON_ONCE(!hnd))
3184                 return NULL;
3185 
3186         iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3187 
3188         return iter;
3189 }
3190 
3191 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3192 {
3193         struct ftrace_iterator *iter = m->private;
3194         void *p = NULL;
3195         loff_t l;
3196 
3197         if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3198                 return NULL;
3199 
3200         if (iter->mod_pos > *pos)
3201                 return NULL;
3202 
3203         iter->probe = NULL;
3204         iter->probe_entry = NULL;
3205         iter->pidx = 0;
3206         for (l = 0; l <= (*pos - iter->mod_pos); ) {
3207                 p = t_probe_next(m, &l);
3208                 if (!p)
3209                         break;
3210         }
3211         if (!p)
3212                 return NULL;
3213 
3214         /* Only set this if we have an item */
3215         iter->flags |= FTRACE_ITER_PROBE;
3216 
3217         return iter;
3218 }
3219 
3220 static int
3221 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3222 {
3223         struct ftrace_func_entry *probe_entry;
3224         struct ftrace_probe_ops *probe_ops;
3225         struct ftrace_func_probe *probe;
3226 
3227         probe = iter->probe;
3228         probe_entry = iter->probe_entry;
3229 
3230         if (WARN_ON_ONCE(!probe || !probe_entry))
3231                 return -EIO;
3232 
3233         probe_ops = probe->probe_ops;
3234 
3235         if (probe_ops->print)
3236                 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3237 
3238         seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3239                    (void *)probe_ops->func);
3240 
3241         return 0;
3242 }
3243 
3244 static void *
3245 t_mod_next(struct seq_file *m, loff_t *pos)
3246 {
3247         struct ftrace_iterator *iter = m->private;
3248         struct trace_array *tr = iter->tr;
3249 
3250         (*pos)++;
3251         iter->pos = *pos;
3252 
3253         iter->mod_list = iter->mod_list->next;
3254 
3255         if (iter->mod_list == &tr->mod_trace ||
3256             iter->mod_list == &tr->mod_notrace) {
3257                 iter->flags &= ~FTRACE_ITER_MOD;
3258                 return NULL;
3259         }
3260 
3261         iter->mod_pos = *pos;
3262 
3263         return iter;
3264 }
3265 
3266 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3267 {
3268         struct ftrace_iterator *iter = m->private;
3269         void *p = NULL;
3270         loff_t l;
3271 
3272         if (iter->func_pos > *pos)
3273                 return NULL;
3274 
3275         iter->mod_pos = iter->func_pos;
3276 
3277         /* probes are only available if tr is set */
3278         if (!iter->tr)
3279                 return NULL;
3280 
3281         for (l = 0; l <= (*pos - iter->func_pos); ) {
3282                 p = t_mod_next(m, &l);
3283                 if (!p)
3284                         break;
3285         }
3286         if (!p) {
3287                 iter->flags &= ~FTRACE_ITER_MOD;
3288                 return t_probe_start(m, pos);
3289         }
3290 
3291         /* Only set this if we have an item */
3292         iter->flags |= FTRACE_ITER_MOD;
3293 
3294         return iter;
3295 }
3296 
3297 static int
3298 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3299 {
3300         struct ftrace_mod_load *ftrace_mod;
3301         struct trace_array *tr = iter->tr;
3302 
3303         if (WARN_ON_ONCE(!iter->mod_list) ||
3304                          iter->mod_list == &tr->mod_trace ||
3305                          iter->mod_list == &tr->mod_notrace)
3306                 return -EIO;
3307 
3308         ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3309 
3310         if (ftrace_mod->func)
3311                 seq_printf(m, "%s", ftrace_mod->func);
3312         else
3313                 seq_putc(m, '*');
3314 
3315         seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3316 
3317         return 0;
3318 }
3319 
3320 static void *
3321 t_func_next(struct seq_file *m, loff_t *pos)
3322 {
3323         struct ftrace_iterator *iter = m->private;
3324         struct dyn_ftrace *rec = NULL;
3325 
3326         (*pos)++;
3327 
3328  retry:
3329         if (iter->idx >= iter->pg->index) {
3330                 if (iter->pg->next) {
3331                         iter->pg = iter->pg->next;
3332                         iter->idx = 0;
3333                         goto retry;
3334                 }
3335         } else {
3336                 rec = &iter->pg->records[iter->idx++];
3337                 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3338                      !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3339 
3340                     ((iter->flags & FTRACE_ITER_ENABLED) &&
3341                      !(rec->flags & FTRACE_FL_ENABLED))) {
3342 
3343                         rec = NULL;
3344                         goto retry;
3345                 }
3346         }
3347 
3348         if (!rec)
3349                 return NULL;
3350 
3351         iter->pos = iter->func_pos = *pos;
3352         iter->func = rec;
3353 
3354         return iter;
3355 }
3356 
3357 static void *
3358 t_next(struct seq_file *m, void *v, loff_t *pos)
3359 {
3360         struct ftrace_iterator *iter = m->private;
3361         loff_t l = *pos; /* t_probe_start() must use original pos */
3362         void *ret;
3363 
3364         if (unlikely(ftrace_disabled))
3365                 return NULL;
3366 
3367         if (iter->flags & FTRACE_ITER_PROBE)
3368                 return t_probe_next(m, pos);
3369 
3370         if (iter->flags & FTRACE_ITER_MOD)
3371                 return t_mod_next(m, pos);
3372 
3373         if (iter->flags & FTRACE_ITER_PRINTALL) {
3374                 /* next must increment pos, and t_probe_start does not */
3375                 (*pos)++;
3376                 return t_mod_start(m, &l);
3377         }
3378 
3379         ret = t_func_next(m, pos);
3380 
3381         if (!ret)
3382                 return t_mod_start(m, &l);
3383 
3384         return ret;
3385 }
3386 
3387 static void reset_iter_read(struct ftrace_iterator *iter)
3388 {
3389         iter->pos = 0;
3390         iter->func_pos = 0;
3391         iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3392 }
3393 
3394 static void *t_start(struct seq_file *m, loff_t *pos)
3395 {
3396         struct ftrace_iterator *iter = m->private;
3397         void *p = NULL;
3398         loff_t l;
3399 
3400         mutex_lock(&ftrace_lock);
3401 
3402         if (unlikely(ftrace_disabled))
3403                 return NULL;
3404 
3405         /*
3406          * If an lseek was done, then reset and start from beginning.
3407          */
3408         if (*pos < iter->pos)
3409                 reset_iter_read(iter);
3410 
3411         /*
3412          * For set_ftrace_filter reading, if we have the filter
3413          * off, we can short cut and just print out that all
3414          * functions are enabled.
3415          */
3416         if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3417             ftrace_hash_empty(iter->hash)) {
3418                 iter->func_pos = 1; /* Account for the message */
3419                 if (*pos > 0)
3420                         return t_mod_start(m, pos);
3421                 iter->flags |= FTRACE_ITER_PRINTALL;
3422                 /* reset in case of seek/pread */
3423                 iter->flags &= ~FTRACE_ITER_PROBE;
3424                 return iter;
3425         }
3426 
3427         if (iter->flags & FTRACE_ITER_MOD)
3428                 return t_mod_start(m, pos);
3429 
3430         /*
3431          * Unfortunately, we need to restart at ftrace_pages_start
3432          * every time we let go of the ftrace_mutex. This is because
3433          * those pointers can change without the lock.
3434          */
3435         iter->pg = ftrace_pages_start;
3436         iter->idx = 0;
3437         for (l = 0; l <= *pos; ) {
3438                 p = t_func_next(m, &l);
3439                 if (!p)
3440                         break;
3441         }
3442 
3443         if (!p)
3444                 return t_mod_start(m, pos);
3445 
3446         return iter;
3447 }
3448 
3449 static void t_stop(struct seq_file *m, void *p)
3450 {
3451         mutex_unlock(&ftrace_lock);
3452 }
3453 
3454 void * __weak
3455 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3456 {
3457         return NULL;
3458 }
3459 
3460 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3461                                 struct dyn_ftrace *rec)
3462 {
3463         void *ptr;
3464 
3465         ptr = arch_ftrace_trampoline_func(ops, rec);
3466         if (ptr)
3467                 seq_printf(m, " ->%pS", ptr);
3468 }
3469 
3470 static int t_show(struct seq_file *m, void *v)
3471 {
3472         struct ftrace_iterator *iter = m->private;
3473         struct dyn_ftrace *rec;
3474 
3475         if (iter->flags & FTRACE_ITER_PROBE)
3476                 return t_probe_show(m, iter);
3477 
3478         if (iter->flags & FTRACE_ITER_MOD)
3479                 return t_mod_show(m, iter);
3480 
3481         if (iter->flags & FTRACE_ITER_PRINTALL) {
3482                 if (iter->flags & FTRACE_ITER_NOTRACE)
3483                         seq_puts(m, "#### no functions disabled ####\n");
3484                 else
3485                         seq_puts(m, "#### all functions enabled ####\n");
3486                 return 0;
3487         }
3488 
3489         rec = iter->func;
3490 
3491         if (!rec)
3492                 return 0;
3493 
3494         seq_printf(m, "%ps", (void *)rec->ip);
3495         if (iter->flags & FTRACE_ITER_ENABLED) {
3496                 struct ftrace_ops *ops;
3497 
3498                 seq_printf(m, " (%ld)%s%s",
3499                            ftrace_rec_count(rec),
3500                            rec->flags & FTRACE_FL_REGS ? " R" : "  ",
3501                            rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ");
3502                 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3503                         ops = ftrace_find_tramp_ops_any(rec);
3504                         if (ops) {
3505                                 do {
3506                                         seq_printf(m, "\ttramp: %pS (%pS)",
3507                                                    (void *)ops->trampoline,
3508                                                    (void *)ops->func);
3509                                         add_trampoline_func(m, ops, rec);
3510                                         ops = ftrace_find_tramp_ops_next(rec, ops);
3511                                 } while (ops);
3512                         } else
3513                                 seq_puts(m, "\ttramp: ERROR!");
3514                 } else {
3515                         add_trampoline_func(m, NULL, rec);
3516                 }
3517         }       
3518 
3519         seq_putc(m, '\n');
3520 
3521         return 0;
3522 }
3523 
3524 static const struct seq_operations show_ftrace_seq_ops = {
3525         .start = t_start,
3526         .next = t_next,
3527         .stop = t_stop,
3528         .show = t_show,
3529 };
3530 
3531 static int
3532 ftrace_avail_open(struct inode *inode, struct file *file)
3533 {
3534         struct ftrace_iterator *iter;
3535 
3536         if (unlikely(ftrace_disabled))
3537                 return -ENODEV;
3538 
3539         iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3540         if (!iter)
3541                 return -ENOMEM;
3542 
3543         iter->pg = ftrace_pages_start;
3544         iter->ops = &global_ops;
3545 
3546         return 0;
3547 }
3548 
3549 static int
3550 ftrace_enabled_open(struct inode *inode, struct file *file)
3551 {
3552         struct ftrace_iterator *iter;
3553 
3554         iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3555         if (!iter)
3556                 return -ENOMEM;
3557 
3558         iter->pg = ftrace_pages_start;
3559         iter->flags = FTRACE_ITER_ENABLED;
3560         iter->ops = &global_ops;
3561 
3562         return 0;
3563 }
3564 
3565 /**
3566  * ftrace_regex_open - initialize function tracer filter files
3567  * @ops: The ftrace_ops that hold the hash filters
3568  * @flag: The type of filter to process
3569  * @inode: The inode, usually passed in to your open routine
3570  * @file: The file, usually passed in to your open routine
3571  *
3572  * ftrace_regex_open() initializes the filter files for the
3573  * @ops. Depending on @flag it may process the filter hash or
3574  * the notrace hash of @ops. With this called from the open
3575  * routine, you can use ftrace_filter_write() for the write
3576  * routine if @flag has FTRACE_ITER_FILTER set, or
3577  * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3578  * tracing_lseek() should be used as the lseek routine, and
3579  * release must call ftrace_regex_release().
3580  */
3581 int
3582 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3583                   struct inode *inode, struct file *file)
3584 {
3585         struct ftrace_iterator *iter;
3586         struct ftrace_hash *hash;
3587         struct list_head *mod_head;
3588         struct trace_array *tr = ops->private;
3589         int ret = 0;
3590 
3591         ftrace_ops_init(ops);
3592 
3593         if (unlikely(ftrace_disabled))
3594                 return -ENODEV;
3595 
3596         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3597         if (!iter)
3598                 return -ENOMEM;
3599 
3600         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3601                 kfree(iter);
3602                 return -ENOMEM;
3603         }
3604 
3605         iter->ops = ops;
3606         iter->flags = flag;
3607         iter->tr = tr;
3608 
3609         mutex_lock(&ops->func_hash->regex_lock);
3610 
3611         if (flag & FTRACE_ITER_NOTRACE) {
3612                 hash = ops->func_hash->notrace_hash;
3613                 mod_head = tr ? &tr->mod_notrace : NULL;
3614         } else {
3615                 hash = ops->func_hash->filter_hash;
3616                 mod_head = tr ? &tr->mod_trace : NULL;
3617         }
3618 
3619         iter->mod_list = mod_head;
3620 
3621         if (file->f_mode & FMODE_WRITE) {
3622                 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3623 
3624                 if (file->f_flags & O_TRUNC) {
3625                         iter->hash = alloc_ftrace_hash(size_bits);
3626                         clear_ftrace_mod_list(mod_head);
3627                 } else {
3628                         iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3629                 }
3630 
3631                 if (!iter->hash) {
3632                         trace_parser_put(&iter->parser);
3633                         kfree(iter);
3634                         ret = -ENOMEM;
3635                         goto out_unlock;
3636                 }
3637         } else
3638                 iter->hash = hash;
3639 
3640         if (file->f_mode & FMODE_READ) {
3641                 iter->pg = ftrace_pages_start;
3642 
3643                 ret = seq_open(file, &show_ftrace_seq_ops);
3644                 if (!ret) {
3645                         struct seq_file *m = file->private_data;
3646                         m->private = iter;
3647                 } else {
3648                         /* Failed */
3649                         free_ftrace_hash(iter->hash);
3650                         trace_parser_put(&iter->parser);
3651                         kfree(iter);
3652                 }
3653         } else
3654                 file->private_data = iter;
3655 
3656  out_unlock:
3657         mutex_unlock(&ops->func_hash->regex_lock);
3658 
3659         return ret;
3660 }
3661 
3662 static int
3663 ftrace_filter_open(struct inode *inode, struct file *file)
3664 {
3665         struct ftrace_ops *ops = inode->i_private;
3666 
3667         return ftrace_regex_open(ops,
3668                         FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3669                         inode, file);
3670 }
3671 
3672 static int
3673 ftrace_notrace_open(struct inode *inode, struct file *file)
3674 {
3675         struct ftrace_ops *ops = inode->i_private;
3676 
3677         return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3678                                  inode, file);
3679 }
3680 
3681 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3682 struct ftrace_glob {
3683         char *search;
3684         unsigned len;
3685         int type;
3686 };
3687 
3688 /*
3689  * If symbols in an architecture don't correspond exactly to the user-visible
3690  * name of what they represent, it is possible to define this function to
3691  * perform the necessary adjustments.
3692 */
3693 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3694 {
3695         return str;
3696 }
3697 
3698 static int ftrace_match(char *str, struct ftrace_glob *g)
3699 {
3700         int matched = 0;
3701         int slen;
3702 
3703         str = arch_ftrace_match_adjust(str, g->search);
3704 
3705         switch (g->type) {
3706         case MATCH_FULL:
3707                 if (strcmp(str, g->search) == 0)
3708                         matched = 1;
3709                 break;
3710         case MATCH_FRONT_ONLY:
3711                 if (strncmp(str, g->search, g->len) == 0)
3712                         matched = 1;
3713                 break;
3714         case MATCH_MIDDLE_ONLY:
3715                 if (strstr(str, g->search))
3716                         matched = 1;
3717                 break;
3718         case MATCH_END_ONLY:
3719                 slen = strlen(str);
3720                 if (slen >= g->len &&
3721                     memcmp(str + slen - g->len, g->search, g->len) == 0)
3722                         matched = 1;
3723                 break;
3724         case MATCH_GLOB:
3725                 if (glob_match(g->search, str))
3726                         matched = 1;
3727                 break;
3728         }
3729 
3730         return matched;
3731 }
3732 
3733 static int
3734 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3735 {
3736         struct ftrace_func_entry *entry;
3737         int ret = 0;
3738 
3739         entry = ftrace_lookup_ip(hash, rec->ip);
3740         if (clear_filter) {
3741                 /* Do nothing if it doesn't exist */
3742                 if (!entry)
3743                         return 0;
3744 
3745                 free_hash_entry(hash, entry);
3746         } else {
3747                 /* Do nothing if it exists */
3748                 if (entry)
3749                         return 0;
3750 
3751                 ret = add_hash_entry(hash, rec->ip);
3752         }
3753         return ret;
3754 }
3755 
3756 static int
3757 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3758                 struct ftrace_glob *mod_g, int exclude_mod)
3759 {
3760         char str[KSYM_SYMBOL_LEN];
3761         char *modname;
3762 
3763         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3764 
3765         if (mod_g) {
3766                 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3767 
3768                 /* blank module name to match all modules */
3769                 if (!mod_g->len) {
3770                         /* blank module globbing: modname xor exclude_mod */
3771                         if (!exclude_mod != !modname)
3772                                 goto func_match;
3773                         return 0;
3774                 }
3775 
3776                 /*
3777                  * exclude_mod is set to trace everything but the given
3778                  * module. If it is set and the module matches, then
3779                  * return 0. If it is not set, and the module doesn't match
3780                  * also return 0. Otherwise, check the function to see if
3781                  * that matches.
3782                  */
3783                 if (!mod_matches == !exclude_mod)
3784                         return 0;
3785 func_match:
3786                 /* blank search means to match all funcs in the mod */
3787                 if (!func_g->len)
3788                         return 1;
3789         }
3790 
3791         return ftrace_match(str, func_g);
3792 }
3793 
3794 static int
3795 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
3796 {
3797         struct ftrace_page *pg;
3798         struct dyn_ftrace *rec;
3799         struct ftrace_glob func_g = { .type = MATCH_FULL };
3800         struct ftrace_glob mod_g = { .type = MATCH_FULL };
3801         struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3802         int exclude_mod = 0;
3803         int found = 0;
3804         int ret;
3805         int clear_filter = 0;
3806 
3807         if (func) {
3808                 func_g.type = filter_parse_regex(func, len, &func_g.search,
3809                                                  &clear_filter);
3810                 func_g.len = strlen(func_g.search);
3811         }
3812 
3813         if (mod) {
3814                 mod_g.type = filter_parse_regex(mod, strlen(mod),
3815                                 &mod_g.search, &exclude_mod);
3816                 mod_g.len = strlen(mod_g.search);
3817         }
3818 
3819         mutex_lock(&ftrace_lock);
3820 
3821         if (unlikely(ftrace_disabled))
3822                 goto out_unlock;
3823 
3824         do_for_each_ftrace_rec(pg, rec) {
3825 
3826                 if (rec->flags & FTRACE_FL_DISABLED)
3827                         continue;
3828 
3829                 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3830                         ret = enter_record(hash, rec, clear_filter);
3831                         if (ret < 0) {
3832                                 found = ret;
3833                                 goto out_unlock;
3834                         }
3835                         found = 1;
3836                 }
3837         } while_for_each_ftrace_rec();
3838  out_unlock:
3839         mutex_unlock(&ftrace_lock);
3840 
3841         return found;
3842 }
3843 
3844 static int
3845 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3846 {
3847         return match_records(hash, buff, len, NULL);
3848 }
3849 
3850 static void ftrace_ops_update_code(struct ftrace_ops *ops,
3851                                    struct ftrace_ops_hash *old_hash)
3852 {
3853         struct ftrace_ops *op;
3854 
3855         if (!ftrace_enabled)
3856                 return;
3857 
3858         if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3859                 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3860                 return;
3861         }
3862 
3863         /*
3864          * If this is the shared global_ops filter, then we need to
3865          * check if there is another ops that shares it, is enabled.
3866          * If so, we still need to run the modify code.
3867          */
3868         if (ops->func_hash != &global_ops.local_hash)
3869                 return;
3870 
3871         do_for_each_ftrace_op(op, ftrace_ops_list) {
3872                 if (op->func_hash == &global_ops.local_hash &&
3873                     op->flags & FTRACE_OPS_FL_ENABLED) {
3874                         ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3875                         /* Only need to do this once */
3876                         return;
3877                 }
3878         } while_for_each_ftrace_op(op);
3879 }
3880 
3881 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3882                                            struct ftrace_hash **orig_hash,
3883                                            struct ftrace_hash *hash,
3884                                            int enable)
3885 {
3886         struct ftrace_ops_hash old_hash_ops;
3887         struct ftrace_hash *old_hash;
3888         int ret;
3889 
3890         old_hash = *orig_hash;
3891         old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3892         old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3893         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3894         if (!ret) {
3895                 ftrace_ops_update_code(ops, &old_hash_ops);
3896                 free_ftrace_hash_rcu(old_hash);
3897         }
3898         return ret;
3899 }
3900 
3901 static bool module_exists(const char *module)
3902 {
3903         /* All modules have the symbol __this_module */
3904         const char this_mod[] = "__this_module";
3905         const int modname_size = MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 1;
3906         char modname[modname_size + 1];
3907         unsigned long val;
3908         int n;
3909 
3910         n = snprintf(modname, modname_size + 1, "%s:%s", module, this_mod);
3911 
3912         if (n > modname_size)
3913                 return false;
3914 
3915         val = module_kallsyms_lookup_name(modname);
3916         return val != 0;
3917 }
3918 
3919 static int cache_mod(struct trace_array *tr,
3920                      const char *func, char *module, int enable)
3921 {
3922         struct ftrace_mod_load *ftrace_mod, *n;
3923         struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3924         int ret;
3925 
3926         mutex_lock(&ftrace_lock);
3927 
3928         /* We do not cache inverse filters */
3929         if (func[0] == '!') {
3930                 func++;
3931                 ret = -EINVAL;
3932 
3933                 /* Look to remove this hash */
3934                 list_for_each_entry_safe(ftrace_mod, n, head, list) {
3935                         if (strcmp(ftrace_mod->module, module) != 0)
3936                                 continue;
3937 
3938                         /* no func matches all */
3939                         if (strcmp(func, "*") == 0 ||
3940                             (ftrace_mod->func &&
3941                              strcmp(ftrace_mod->func, func) == 0)) {
3942                                 ret = 0;
3943                                 free_ftrace_mod(ftrace_mod);
3944                                 continue;
3945                         }
3946                 }
3947                 goto out;
3948         }
3949 
3950         ret = -EINVAL;
3951         /* We only care about modules that have not been loaded yet */
3952         if (module_exists(module))
3953                 goto out;
3954 
3955         /* Save this string off, and execute it when the module is loaded */
3956         ret = ftrace_add_mod(tr, func, module, enable);
3957  out:
3958         mutex_unlock(&ftrace_lock);
3959 
3960         return ret;
3961 }
3962 
3963 static int
3964 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3965                  int reset, int enable);
3966 
3967 #ifdef CONFIG_MODULES
3968 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
3969                              char *mod, bool enable)
3970 {
3971         struct ftrace_mod_load *ftrace_mod, *n;
3972         struct ftrace_hash **orig_hash, *new_hash;
3973         LIST_HEAD(process_mods);
3974         char *func;
3975         int ret;
3976 
3977         mutex_lock(&ops->func_hash->regex_lock);
3978 
3979         if (enable)
3980                 orig_hash = &ops->func_hash->filter_hash;
3981         else
3982                 orig_hash = &ops->func_hash->notrace_hash;
3983 
3984         new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
3985                                               *orig_hash);
3986         if (!new_hash)
3987                 goto out; /* warn? */
3988 
3989         mutex_lock(&ftrace_lock);
3990 
3991         list_for_each_entry_safe(ftrace_mod, n, head, list) {
3992 
3993                 if (strcmp(ftrace_mod->module, mod) != 0)
3994                         continue;
3995 
3996                 if (ftrace_mod->func)
3997                         func = kstrdup(ftrace_mod->func, GFP_KERNEL);
3998                 else
3999                         func = kstrdup("*", GFP_KERNEL);
4000 
4001                 if (!func) /* warn? */
4002                         continue;
4003 
4004                 list_del(&ftrace_mod->list);
4005                 list_add(&ftrace_mod->list, &process_mods);
4006 
4007                 /* Use the newly allocated func, as it may be "*" */
4008                 kfree(ftrace_mod->func);
4009                 ftrace_mod->func = func;
4010         }
4011 
4012         mutex_unlock(&ftrace_lock);
4013 
4014         list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4015 
4016                 func = ftrace_mod->func;
4017 
4018                 /* Grabs ftrace_lock, which is why we have this extra step */
4019                 match_records(new_hash, func, strlen(func), mod);
4020                 free_ftrace_mod(ftrace_mod);
4021         }
4022 
4023         if (enable && list_empty(head))
4024                 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4025 
4026         mutex_lock(&ftrace_lock);
4027 
4028         ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4029                                               new_hash, enable);
4030         mutex_unlock(&ftrace_lock);
4031 
4032  out:
4033         mutex_unlock(&ops->func_hash->regex_lock);
4034 
4035         free_ftrace_hash(new_hash);
4036 }
4037 
4038 static void process_cached_mods(const char *mod_name)
4039 {
4040         struct trace_array *tr;
4041         char *mod;
4042 
4043         mod = kstrdup(mod_name, GFP_KERNEL);
4044         if (!mod)
4045                 return;
4046 
4047         mutex_lock(&trace_types_lock);
4048         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4049                 if (!list_empty(&tr->mod_trace))
4050                         process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4051                 if (!list_empty(&tr->mod_notrace))
4052                         process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4053         }
4054         mutex_unlock(&trace_types_lock);
4055 
4056         kfree(mod);
4057 }
4058 #endif
4059 
4060 /*
4061  * We register the module command as a template to show others how
4062  * to register the a command as well.
4063  */
4064 
4065 static int
4066 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4067                     char *func_orig, char *cmd, char *module, int enable)
4068 {
4069         char *func;
4070         int ret;
4071 
4072         /* match_records() modifies func, and we need the original */
4073         func = kstrdup(func_orig, GFP_KERNEL);
4074         if (!func)
4075                 return -ENOMEM;
4076 
4077         /*
4078          * cmd == 'mod' because we only registered this func
4079          * for the 'mod' ftrace_func_command.
4080          * But if you register one func with multiple commands,
4081          * you can tell which command was used by the cmd
4082          * parameter.
4083          */
4084         ret = match_records(hash, func, strlen(func), module);
4085         kfree(func);
4086 
4087         if (!ret)
4088                 return cache_mod(tr, func_orig, module, enable);
4089         if (ret < 0)
4090                 return ret;
4091         return 0;
4092 }
4093 
4094 static struct ftrace_func_command ftrace_mod_cmd = {
4095         .name                   = "mod",
4096         .func                   = ftrace_mod_callback,
4097 };
4098 
4099 static int __init ftrace_mod_cmd_init(void)
4100 {
4101         return register_ftrace_command(&ftrace_mod_cmd);
4102 }
4103 core_initcall(ftrace_mod_cmd_init);
4104 
4105 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4106                                       struct ftrace_ops *op, struct pt_regs *pt_regs)
4107 {
4108         struct ftrace_probe_ops *probe_ops;
4109         struct ftrace_func_probe *probe;
4110 
4111         probe = container_of(op, struct ftrace_func_probe, ops);
4112         probe_ops = probe->probe_ops;
4113 
4114         /*
4115          * Disable preemption for these calls to prevent a RCU grace
4116          * period. This syncs the hash iteration and freeing of items
4117          * on the hash. rcu_read_lock is too dangerous here.
4118          */
4119         preempt_disable_notrace();
4120         probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4121         preempt_enable_notrace();
4122 }
4123 
4124 struct ftrace_func_map {
4125         struct ftrace_func_entry        entry;
4126         void                            *data;
4127 };
4128 
4129 struct ftrace_func_mapper {
4130         struct ftrace_hash              hash;
4131 };
4132 
4133 /**
4134  * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4135  *
4136  * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4137  */
4138 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4139 {
4140         struct ftrace_hash *hash;
4141 
4142         /*
4143          * The mapper is simply a ftrace_hash, but since the entries
4144          * in the hash are not ftrace_func_entry type, we define it
4145          * as a separate structure.
4146          */
4147         hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4148         return (struct ftrace_func_mapper *)hash;
4149 }
4150 
4151 /**
4152  * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4153  * @mapper: The mapper that has the ip maps
4154  * @ip: the instruction pointer to find the data for
4155  *
4156  * Returns the data mapped to @ip if found otherwise NULL. The return
4157  * is actually the address of the mapper data pointer. The address is
4158  * returned for use cases where the data is no bigger than a long, and
4159  * the user can use the data pointer as its data instead of having to
4160  * allocate more memory for the reference.
4161  */
4162 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4163                                   unsigned long ip)
4164 {
4165         struct ftrace_func_entry *entry;
4166         struct ftrace_func_map *map;
4167 
4168         entry = ftrace_lookup_ip(&mapper->hash, ip);
4169         if (!entry)
4170                 return NULL;
4171 
4172         map = (struct ftrace_func_map *)entry;
4173         return &map->data;
4174 }
4175 
4176 /**
4177  * ftrace_func_mapper_add_ip - Map some data to an ip
4178  * @mapper: The mapper that has the ip maps
4179  * @ip: The instruction pointer address to map @data to
4180  * @data: The data to map to @ip
4181  *
4182  * Returns 0 on succes otherwise an error.
4183  */
4184 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4185                               unsigned long ip, void *data)
4186 {
4187         struct ftrace_func_entry *entry;
4188         struct ftrace_func_map *map;
4189 
4190         entry = ftrace_lookup_ip(&mapper->hash, ip);
4191         if (entry)
4192                 return -EBUSY;
4193 
4194         map = kmalloc(sizeof(*map), GFP_KERNEL);
4195         if (!map)
4196                 return -ENOMEM;
4197 
4198         map->entry.ip = ip;
4199         map->data = data;
4200 
4201         __add_hash_entry(&mapper->hash, &map->entry);
4202 
4203         return 0;
4204 }
4205 
4206 /**
4207  * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4208  * @mapper: The mapper that has the ip maps
4209  * @ip: The instruction pointer address to remove the data from
4210  *
4211  * Returns the data if it is found, otherwise NULL.
4212  * Note, if the data pointer is used as the data itself, (see 
4213  * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4214  * if the data pointer was set to zero.
4215  */
4216 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4217                                    unsigned long ip)
4218 {
4219         struct ftrace_func_entry *entry;
4220         struct ftrace_func_map *map;
4221         void *data;
4222 
4223         entry = ftrace_lookup_ip(&mapper->hash, ip);
4224         if (!entry)
4225                 return NULL;
4226 
4227         map = (struct ftrace_func_map *)entry;
4228         data = map->data;
4229 
4230         remove_hash_entry(&mapper->hash, entry);
4231         kfree(entry);
4232 
4233         return data;
4234 }
4235 
4236 /**
4237  * free_ftrace_func_mapper - free a mapping of ips and data
4238  * @mapper: The mapper that has the ip maps
4239  * @free_func: A function to be called on each data item.
4240  *
4241  * This is used to free the function mapper. The @free_func is optional
4242  * and can be used if the data needs to be freed as well.
4243  */
4244 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4245                              ftrace_mapper_func free_func)
4246 {
4247         struct ftrace_func_entry *entry;
4248         struct ftrace_func_map *map;
4249         struct hlist_head *hhd;
4250         int size = 1 << mapper->hash.size_bits;
4251         int i;
4252 
4253         if (free_func && mapper->hash.count) {
4254                 for (i = 0; i < size; i++) {
4255                         hhd = &mapper->hash.buckets[i];
4256                         hlist_for_each_entry(entry, hhd, hlist) {
4257                                 map = (struct ftrace_func_map *)entry;
4258                                 free_func(map);
4259                         }
4260                 }
4261         }
4262         free_ftrace_hash(&mapper->hash);
4263 }
4264 
4265 static void release_probe(struct ftrace_func_probe *probe)
4266 {
4267         struct ftrace_probe_ops *probe_ops;
4268 
4269         mutex_lock(&ftrace_lock);
4270 
4271         WARN_ON(probe->ref <= 0);
4272 
4273         /* Subtract the ref that was used to protect this instance */
4274         probe->ref--;
4275 
4276         if (!probe->ref) {
4277                 probe_ops = probe->probe_ops;
4278                 /*
4279                  * Sending zero as ip tells probe_ops to free
4280                  * the probe->data itself
4281                  */
4282                 if (probe_ops->free)
4283                         probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4284                 list_del(&probe->list);
4285                 kfree(probe);
4286         }
4287         mutex_unlock(&ftrace_lock);
4288 }
4289 
4290 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4291 {
4292         /*
4293          * Add one ref to keep it from being freed when releasing the
4294          * ftrace_lock mutex.
4295          */
4296         probe->ref++;
4297 }
4298 
4299 int
4300 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4301                                struct ftrace_probe_ops *probe_ops,
4302                                void *data)
4303 {
4304         struct ftrace_func_entry *entry;
4305         struct ftrace_func_probe *probe;
4306         struct ftrace_hash **orig_hash;
4307         struct ftrace_hash *old_hash;
4308         struct ftrace_hash *hash;
4309         int count = 0;
4310         int size;
4311         int ret;
4312         int i;
4313 
4314         if (WARN_ON(!tr))
4315                 return -EINVAL;
4316 
4317         /* We do not support '!' for function probes */
4318         if (WARN_ON(glob[0] == '!'))
4319                 return -EINVAL;
4320 
4321 
4322         mutex_lock(&ftrace_lock);
4323         /* Check if the probe_ops is already registered */
4324         list_for_each_entry(probe, &tr->func_probes, list) {
4325                 if (probe->probe_ops == probe_ops)
4326                         break;
4327         }
4328         if (&probe->list == &tr->func_probes) {
4329                 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4330                 if (!probe) {
4331                         mutex_unlock(&ftrace_lock);
4332                         return -ENOMEM;
4333                 }
4334                 probe->probe_ops = probe_ops;
4335                 probe->ops.func = function_trace_probe_call;
4336                 probe->tr = tr;
4337                 ftrace_ops_init(&probe->ops);
4338                 list_add(&probe->list, &tr->func_probes);
4339         }
4340 
4341         acquire_probe_locked(probe);
4342 
4343         mutex_unlock(&ftrace_lock);
4344 
4345         mutex_lock(&probe->ops.func_hash->regex_lock);
4346 
4347         orig_hash = &probe->ops.func_hash->filter_hash;
4348         old_hash = *orig_hash;
4349         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4350 
4351         ret = ftrace_match_records(hash, glob, strlen(glob));
4352 
4353         /* Nothing found? */
4354         if (!ret)
4355                 ret = -EINVAL;
4356 
4357         if (ret < 0)
4358                 goto out;
4359 
4360         size = 1 << hash->size_bits;
4361         for (i = 0; i < size; i++) {
4362                 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4363                         if (ftrace_lookup_ip(old_hash, entry->ip))
4364                                 continue;
4365                         /*
4366                          * The caller might want to do something special
4367                          * for each function we find. We call the callback
4368                          * to give the caller an opportunity to do so.
4369                          */
4370                         if (probe_ops->init) {
4371                                 ret = probe_ops->init(probe_ops, tr,
4372                                                       entry->ip, data,
4373                                                       &probe->data);
4374                                 if (ret < 0) {
4375                                         if (probe_ops->free && count)
4376                                                 probe_ops->free(probe_ops, tr,
4377                                                                 0, probe->data);
4378                                         probe->data = NULL;
4379                                         goto out;
4380                                 }
4381                         }
4382                         count++;
4383                 }
4384         }
4385 
4386         mutex_lock(&ftrace_lock);
4387 
4388         if (!count) {
4389                 /* Nothing was added? */
4390                 ret = -EINVAL;
4391                 goto out_unlock;
4392         }
4393 
4394         ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4395                                               hash, 1);
4396         if (ret < 0)
4397                 goto err_unlock;
4398 
4399         /* One ref for each new function traced */
4400         probe->ref += count;
4401 
4402         if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4403                 ret = ftrace_startup(&probe->ops, 0);
4404 
4405  out_unlock:
4406         mutex_unlock(&ftrace_lock);
4407 
4408         if (!ret)
4409                 ret = count;
4410  out:
4411         mutex_unlock(&probe->ops.func_hash->regex_lock);
4412         free_ftrace_hash(hash);
4413 
4414         release_probe(probe);
4415 
4416         return ret;
4417 
4418  err_unlock:
4419         if (!probe_ops->free || !count)
4420                 goto out_unlock;
4421 
4422         /* Failed to do the move, need to call the free functions */
4423         for (i = 0; i < size; i++) {
4424                 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4425                         if (ftrace_lookup_ip(old_hash, entry->ip))
4426                                 continue;
4427                         probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4428                 }
4429         }
4430         goto out_unlock;
4431 }
4432 
4433 int
4434 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4435                                       struct ftrace_probe_ops *probe_ops)
4436 {
4437         struct ftrace_ops_hash old_hash_ops;
4438         struct ftrace_func_entry *entry;
4439         struct ftrace_func_probe *probe;
4440         struct ftrace_glob func_g;
4441         struct ftrace_hash **orig_hash;
4442         struct ftrace_hash *old_hash;
4443         struct ftrace_hash *hash = NULL;
4444         struct hlist_node *tmp;
4445         struct hlist_head hhd;
4446         char str[KSYM_SYMBOL_LEN];
4447         int count = 0;
4448         int i, ret = -ENODEV;
4449         int size;
4450 
4451         if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4452                 func_g.search = NULL;
4453         else {
4454                 int not;
4455 
4456                 func_g.type = filter_parse_regex(glob, strlen(glob),
4457                                                  &func_g.search, &not);
4458                 func_g.len = strlen(func_g.search);
4459 
4460                 /* we do not support '!' for function probes */
4461                 if (WARN_ON(not))
4462                         return -EINVAL;
4463         }
4464 
4465         mutex_lock(&ftrace_lock);
4466         /* Check if the probe_ops is already registered */
4467         list_for_each_entry(probe, &tr->func_probes, list) {
4468                 if (probe->probe_ops == probe_ops)
4469                         break;
4470         }
4471         if (&probe->list == &tr->func_probes)
4472                 goto err_unlock_ftrace;
4473 
4474         ret = -EINVAL;
4475         if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4476                 goto err_unlock_ftrace;
4477 
4478         acquire_probe_locked(probe);
4479 
4480         mutex_unlock(&ftrace_lock);
4481 
4482         mutex_lock(&probe->ops.func_hash->regex_lock);
4483 
4484         orig_hash = &probe->ops.func_hash->filter_hash;
4485         old_hash = *orig_hash;
4486 
4487         if (ftrace_hash_empty(old_hash))
4488                 goto out_unlock;
4489 
4490         old_hash_ops.filter_hash = old_hash;
4491         /* Probes only have filters */
4492         old_hash_ops.notrace_hash = NULL;
4493 
4494         ret = -ENOMEM;
4495         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4496         if (!hash)
4497                 goto out_unlock;
4498 
4499         INIT_HLIST_HEAD(&hhd);
4500 
4501         size = 1 << hash->size_bits;
4502         for (i = 0; i < size; i++) {
4503                 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4504 
4505                         if (func_g.search) {
4506                                 kallsyms_lookup(entry->ip, NULL, NULL,
4507                                                 NULL, str);
4508                                 if (!ftrace_match(str, &func_g))
4509                                         continue;
4510                         }
4511                         count++;
4512                         remove_hash_entry(hash, entry);
4513                         hlist_add_head(&entry->hlist, &hhd);
4514                 }
4515         }
4516 
4517         /* Nothing found? */
4518         if (!count) {
4519                 ret = -EINVAL;
4520                 goto out_unlock;
4521         }
4522 
4523         mutex_lock(&ftrace_lock);
4524 
4525         WARN_ON(probe->ref < count);
4526 
4527         probe->ref -= count;
4528 
4529         if (ftrace_hash_empty(hash))
4530                 ftrace_shutdown(&probe->ops, 0);
4531 
4532         ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4533                                               hash, 1);
4534 
4535         /* still need to update the function call sites */
4536         if (ftrace_enabled && !ftrace_hash_empty(hash))
4537                 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4538                                        &old_hash_ops);
4539         synchronize_sched();
4540 
4541         hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4542                 hlist_del(&entry->hlist);
4543                 if (probe_ops->free)
4544                         probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4545                 kfree(entry);
4546         }
4547         mutex_unlock(&ftrace_lock);
4548 
4549  out_unlock:
4550         mutex_unlock(&probe->ops.func_hash->regex_lock);
4551         free_ftrace_hash(hash);
4552 
4553         release_probe(probe);
4554 
4555         return ret;
4556 
4557  err_unlock_ftrace:
4558         mutex_unlock(&ftrace_lock);
4559         return ret;
4560 }
4561 
4562 void clear_ftrace_function_probes(struct trace_array *tr)
4563 {
4564         struct ftrace_func_probe *probe, *n;
4565 
4566         list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4567                 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4568 }
4569 
4570 static LIST_HEAD(ftrace_commands);
4571 static DEFINE_MUTEX(ftrace_cmd_mutex);
4572 
4573 /*
4574  * Currently we only register ftrace commands from __init, so mark this
4575  * __init too.
4576  */
4577 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4578 {
4579         struct ftrace_func_command *p;
4580         int ret = 0;
4581 
4582         mutex_lock(&ftrace_cmd_mutex);
4583         list_for_each_entry(p, &ftrace_commands, list) {
4584                 if (strcmp(cmd->name, p->name) == 0) {
4585                         ret = -EBUSY;
4586                         goto out_unlock;
4587                 }
4588         }
4589         list_add(&cmd->list, &ftrace_commands);
4590  out_unlock:
4591         mutex_unlock(&ftrace_cmd_mutex);
4592 
4593         return ret;
4594 }
4595 
4596 /*
4597  * Currently we only unregister ftrace commands from __init, so mark
4598  * this __init too.
4599  */
4600 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4601 {
4602         struct ftrace_func_command *p, *n;
4603         int ret = -ENODEV;
4604 
4605         mutex_lock(&ftrace_cmd_mutex);
4606         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4607                 if (strcmp(cmd->name, p->name) == 0) {
4608                         ret = 0;
4609                         list_del_init(&p->list);
4610                         goto out_unlock;
4611                 }
4612         }
4613  out_unlock:
4614         mutex_unlock(&ftrace_cmd_mutex);
4615 
4616         return ret;
4617 }
4618 
4619 static int ftrace_process_regex(struct ftrace_iterator *iter,
4620                                 char *buff, int len, int enable)
4621 {
4622         struct ftrace_hash *hash = iter->hash;
4623         struct trace_array *tr = iter->ops->private;
4624         char *func, *command, *next = buff;
4625         struct ftrace_func_command *p;
4626         int ret = -EINVAL;
4627 
4628         func = strsep(&next, ":");
4629 
4630         if (!next) {
4631                 ret = ftrace_match_records(hash, func, len);
4632                 if (!ret)
4633                         ret = -EINVAL;
4634                 if (ret < 0)
4635                         return ret;
4636                 return 0;
4637         }
4638 
4639         /* command found */
4640 
4641         command = strsep(&next, ":");
4642 
4643         mutex_lock(&ftrace_cmd_mutex);
4644         list_for_each_entry(p, &ftrace_commands, list) {
4645                 if (strcmp(p->name, command) == 0) {
4646                         ret = p->func(tr, hash, func, command, next, enable);
4647                         goto out_unlock;
4648                 }
4649         }
4650  out_unlock:
4651         mutex_unlock(&ftrace_cmd_mutex);
4652 
4653         return ret;
4654 }
4655 
4656 static ssize_t
4657 ftrace_regex_write(struct file *file, const char __user *ubuf,
4658                    size_t cnt, loff_t *ppos, int enable)
4659 {
4660         struct ftrace_iterator *iter;
4661         struct trace_parser *parser;
4662         ssize_t ret, read;
4663 
4664         if (!cnt)
4665                 return 0;
4666 
4667         if (file->f_mode & FMODE_READ) {
4668                 struct seq_file *m = file->private_data;
4669                 iter = m->private;
4670         } else
4671                 iter = file->private_data;
4672 
4673         if (unlikely(ftrace_disabled))
4674                 return -ENODEV;
4675 
4676         /* iter->hash is a local copy, so we don't need regex_lock */
4677 
4678         parser = &iter->parser;
4679         read = trace_get_user(parser, ubuf, cnt, ppos);
4680 
4681         if (read >= 0 && trace_parser_loaded(parser) &&
4682             !trace_parser_cont(parser)) {
4683                 ret = ftrace_process_regex(iter, parser->buffer,
4684                                            parser->idx, enable);
4685                 trace_parser_clear(parser);
4686                 if (ret < 0)
4687                         goto out;
4688         }
4689 
4690         ret = read;
4691  out:
4692         return ret;
4693 }
4694 
4695 ssize_t
4696 ftrace_filter_write(struct file *file, const char __user *ubuf,
4697                     size_t cnt, loff_t *ppos)
4698 {
4699         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4700 }
4701 
4702 ssize_t
4703 ftrace_notrace_write(struct file *file, const char __user *ubuf,
4704                      size_t cnt, loff_t *ppos)
4705 {
4706         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4707 }
4708 
4709 static int
4710 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4711 {
4712         struct ftrace_func_entry *entry;
4713 
4714         if (!ftrace_location(ip))
4715                 return -EINVAL;
4716 
4717         if (remove) {
4718                 entry = ftrace_lookup_ip(hash, ip);
4719                 if (!entry)
4720                         return -ENOENT;
4721                 free_hash_entry(hash, entry);
4722                 return 0;
4723         }
4724 
4725         return add_hash_entry(hash, ip);
4726 }
4727 
4728 static int
4729 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4730                 unsigned long ip, int remove, int reset, int enable)
4731 {
4732         struct ftrace_hash **orig_hash;
4733         struct ftrace_hash *hash;
4734         int ret;
4735 
4736         if (unlikely(ftrace_disabled))
4737                 return -ENODEV;
4738 
4739         mutex_lock(&ops->func_hash->regex_lock);
4740 
4741         if (enable)
4742                 orig_hash = &ops->func_hash->filter_hash;
4743         else
4744                 orig_hash = &ops->func_hash->notrace_hash;
4745 
4746         if (reset)
4747                 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4748         else
4749                 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4750 
4751         if (!hash) {
4752                 ret = -ENOMEM;
4753                 goto out_regex_unlock;
4754         }
4755 
4756         if (buf && !ftrace_match_records(hash, buf, len)) {
4757                 ret = -EINVAL;
4758                 goto out_regex_unlock;
4759         }
4760         if (ip) {
4761                 ret = ftrace_match_addr(hash, ip, remove);
4762                 if (ret < 0)
4763                         goto out_regex_unlock;
4764         }
4765 
4766         mutex_lock(&ftrace_lock);
4767         ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
4768         mutex_unlock(&ftrace_lock);
4769 
4770  out_regex_unlock:
4771         mutex_unlock(&ops->func_hash->regex_lock);
4772 
4773         free_ftrace_hash(hash);
4774         return ret;
4775 }
4776 
4777 static int
4778 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4779                 int reset, int enable)
4780 {
4781         return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
4782 }
4783 
4784 /**
4785  * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4786  * @ops - the ops to set the filter with
4787  * @ip - the address to add to or remove from the filter.
4788  * @remove - non zero to remove the ip from the filter
4789  * @reset - non zero to reset all filters before applying this filter.
4790  *
4791  * Filters denote which functions should be enabled when tracing is enabled
4792  * If @ip is NULL, it failes to update filter.
4793  */
4794 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4795                          int remove, int reset)
4796 {
4797         ftrace_ops_init(ops);
4798         return ftrace_set_addr(ops, ip, remove, reset, 1);
4799 }
4800 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4801 
4802 /**
4803  * ftrace_ops_set_global_filter - setup ops to use global filters
4804  * @ops - the ops which will use the global filters
4805  *
4806  * ftrace users who need global function trace filtering should call this.
4807  * It can set the global filter only if ops were not initialized before.
4808  */
4809 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4810 {
4811         if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4812                 return;
4813 
4814         ftrace_ops_init(ops);
4815         ops->func_hash = &global_ops.local_hash;
4816 }
4817 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4818 
4819 static int
4820 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4821                  int reset, int enable)
4822 {
4823         return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4824 }
4825 
4826 /**
4827  * ftrace_set_filter - set a function to filter on in ftrace
4828  * @ops - the ops to set the filter with
4829  * @buf - the string that holds the function filter text.
4830  * @len - the length of the string.
4831  * @reset - non zero to reset all filters before applying this filter.
4832  *
4833  * Filters denote which functions should be enabled when tracing is enabled.
4834  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4835  */
4836 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4837                        int len, int reset)
4838 {
4839         ftrace_ops_init(ops);
4840         return ftrace_set_regex(ops, buf, len, reset, 1);
4841 }
4842 EXPORT_SYMBOL_GPL(ftrace_set_filter);
4843 
4844 /**
4845  * ftrace_set_notrace - set a function to not trace in ftrace
4846  * @ops - the ops to set the notrace filter with
4847  * @buf - the string that holds the function notrace text.
4848  * @len - the length of the string.
4849  * @reset - non zero to reset all filters before applying this filter.
4850  *
4851  * Notrace Filters denote which functions should not be enabled when tracing
4852  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4853  * for tracing.
4854  */
4855 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4856                         int len, int reset)
4857 {
4858         ftrace_ops_init(ops);
4859         return ftrace_set_regex(ops, buf, len, reset, 0);
4860 }
4861 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4862 /**
4863  * ftrace_set_global_filter - set a function to filter on with global tracers
4864  * @buf - the string that holds the function filter text.
4865  * @len - the length of the string.
4866  * @reset - non zero to reset all filters before applying this filter.
4867  *
4868  * Filters denote which functions should be enabled when tracing is enabled.
4869  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4870  */
4871 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4872 {
4873         ftrace_set_regex(&global_ops, buf, len, reset, 1);
4874 }
4875 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4876 
4877 /**
4878  * ftrace_set_global_notrace - set a function to not trace with global tracers
4879  * @buf - the string that holds the function notrace text.
4880  * @len - the length of the string.
4881  * @reset - non zero to reset all filters before applying this filter.
4882  *
4883  * Notrace Filters denote which functions should not be enabled when tracing
4884  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4885  * for tracing.
4886  */
4887 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4888 {
4889         ftrace_set_regex(&global_ops, buf, len, reset, 0);
4890 }
4891 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4892 
4893 /*
4894  * command line interface to allow users to set filters on boot up.
4895  */
4896 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
4897 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4898 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4899 
4900 /* Used by function selftest to not test if filter is set */
4901 bool ftrace_filter_param __initdata;
4902 
4903 static int __init set_ftrace_notrace(char *str)
4904 {
4905         ftrace_filter_param = true;
4906         strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4907         return 1;
4908 }
4909 __setup("ftrace_notrace=", set_ftrace_notrace);
4910 
4911 static int __init set_ftrace_filter(char *str)
4912 {
4913         ftrace_filter_param = true;
4914         strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4915         return 1;
4916 }
4917 __setup("ftrace_filter=", set_ftrace_filter);
4918 
4919 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4920 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4921 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4922 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4923 
4924 static int __init set_graph_function(char *str)
4925 {
4926         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4927         return 1;
4928 }
4929 __setup("ftrace_graph_filter=", set_graph_function);
4930 
4931 static int __init set_graph_notrace_function(char *str)
4932 {
4933         strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4934         return 1;
4935 }
4936 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
4937 
4938 static int __init set_graph_max_depth_function(char *str)
4939 {
4940         if (!str)
4941                 return 0;
4942         fgraph_max_depth = simple_strtoul(str, NULL, 0);
4943         return 1;
4944 }
4945 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
4946 
4947 static void __init set_ftrace_early_graph(char *buf, int enable)
4948 {
4949         int ret;
4950         char *func;
4951         struct ftrace_hash *hash;
4952 
4953         hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4954         if (WARN_ON(!hash))
4955                 return;
4956 
4957         while (buf) {
4958                 func = strsep(&buf, ",");
4959                 /* we allow only one expression at a time */
4960                 ret = ftrace_graph_set_hash(hash, func);
4961                 if (ret)
4962                         printk(KERN_DEBUG "ftrace: function %s not "
4963                                           "traceable\n", func);
4964         }
4965 
4966         if (enable)
4967                 ftrace_graph_hash = hash;
4968         else
4969                 ftrace_graph_notrace_hash = hash;
4970 }
4971 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4972 
4973 void __init
4974 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4975 {
4976         char *func;
4977 
4978         ftrace_ops_init(ops);
4979 
4980         while (buf) {
4981                 func = strsep(&buf, ",");
4982                 ftrace_set_regex(ops, func, strlen(func), 0, enable);
4983         }
4984 }
4985 
4986 static void __init set_ftrace_early_filters(void)
4987 {
4988         if (ftrace_filter_buf[0])
4989                 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4990         if (ftrace_notrace_buf[0])
4991                 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4992 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4993         if (ftrace_graph_buf[0])
4994                 set_ftrace_early_graph(ftrace_graph_buf, 1);
4995         if (ftrace_graph_notrace_buf[0])
4996                 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4997 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4998 }
4999 
5000 int ftrace_regex_release(struct inode *inode, struct file *file)
5001 {
5002         struct seq_file *m = (struct seq_file *)file->private_data;
5003         struct ftrace_iterator *iter;
5004         struct ftrace_hash **orig_hash;
5005         struct trace_parser *parser;
5006         int filter_hash;
5007         int ret;
5008 
5009         if (file->f_mode & FMODE_READ) {
5010                 iter = m->private;
5011                 seq_release(inode, file);
5012         } else
5013                 iter = file->private_data;
5014 
5015         parser = &iter->parser;
5016         if (trace_parser_loaded(parser)) {
5017                 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5018         }
5019 
5020         trace_parser_put(parser);
5021 
5022         mutex_lock(&iter->ops->func_hash->regex_lock);
5023 
5024         if (file->f_mode & FMODE_WRITE) {
5025                 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5026 
5027                 if (filter_hash) {
5028                         orig_hash = &iter->ops->func_hash->filter_hash;
5029                         if (iter->tr && !list_empty(&iter->tr->mod_trace))
5030                                 iter->hash->flags |= FTRACE_HASH_FL_MOD;
5031                 } else
5032                         orig_hash = &iter->ops->func_hash->notrace_hash;
5033 
5034                 mutex_lock(&ftrace_lock);
5035                 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5036                                                       iter->hash, filter_hash);
5037                 mutex_unlock(&ftrace_lock);
5038         } else {
5039                 /* For read only, the hash is the ops hash */
5040                 iter->hash = NULL;
5041         }
5042 
5043         mutex_unlock(&iter->ops->func_hash->regex_lock);
5044         free_ftrace_hash(iter->hash);
5045         kfree(iter);
5046 
5047         return 0;
5048 }
5049 
5050 static const struct file_operations ftrace_avail_fops = {
5051         .open = ftrace_avail_open,
5052         .read = seq_read,
5053         .llseek = seq_lseek,
5054         .release = seq_release_private,
5055 };
5056 
5057 static const struct file_operations ftrace_enabled_fops = {
5058         .open = ftrace_enabled_open,
5059         .read = seq_read,
5060         .llseek = seq_lseek,
5061         .release = seq_release_private,
5062 };
5063 
5064 static const struct file_operations ftrace_filter_fops = {
5065         .open = ftrace_filter_open,
5066         .read = seq_read,
5067         .write = ftrace_filter_write,
5068         .llseek = tracing_lseek,
5069         .release = ftrace_regex_release,
5070 };
5071 
5072 static const struct file_operations ftrace_notrace_fops = {
5073         .open = ftrace_notrace_open,
5074         .read = seq_read,
5075         .write = ftrace_notrace_write,
5076         .llseek = tracing_lseek,
5077         .release = ftrace_regex_release,
5078 };
5079 
5080 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5081 
5082 static DEFINE_MUTEX(graph_lock);
5083 
5084 struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
5085 struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
5086 
5087 enum graph_filter_type {
5088         GRAPH_FILTER_NOTRACE    = 0,
5089         GRAPH_FILTER_FUNCTION,
5090 };
5091 
5092 #define FTRACE_GRAPH_EMPTY      ((void *)1)
5093 
5094 struct ftrace_graph_data {
5095         struct ftrace_hash              *hash;
5096         struct ftrace_func_entry        *entry;
5097         int                             idx;   /* for hash table iteration */
5098         enum graph_filter_type          type;
5099         struct ftrace_hash              *new_hash;
5100         const struct seq_operations     *seq_ops;
5101         struct trace_parser             parser;
5102 };
5103 
5104 static void *
5105 __g_next(struct seq_file *m, loff_t *pos)
5106 {
5107         struct ftrace_graph_data *fgd = m->private;
5108         struct ftrace_func_entry *entry = fgd->entry;
5109         struct hlist_head *head;
5110         int i, idx = fgd->idx;
5111 
5112         if (*pos >= fgd->hash->count)
5113                 return NULL;
5114 
5115         if (entry) {
5116                 hlist_for_each_entry_continue(entry, hlist) {
5117                         fgd->entry = entry;
5118                         return entry;
5119                 }
5120 
5121                 idx++;
5122         }
5123 
5124         for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5125                 head = &fgd->hash->buckets[i];
5126                 hlist_for_each_entry(entry, head, hlist) {
5127                         fgd->entry = entry;
5128                         fgd->idx = i;
5129                         return entry;
5130                 }
5131         }
5132         return NULL;
5133 }
5134 
5135 static void *
5136 g_next(struct seq_file *m, void *v, loff_t *pos)
5137 {
5138         (*pos)++;
5139         return __g_next(m, pos);
5140 }
5141 
5142 static void *g_start(struct seq_file *m, loff_t *pos)
5143 {
5144         struct ftrace_graph_data *fgd = m->private;
5145 
5146         mutex_lock(&graph_lock);
5147 
5148         if (fgd->type == GRAPH_FILTER_FUNCTION)
5149                 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5150                                         lockdep_is_held(&graph_lock));
5151         else
5152                 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5153                                         lockdep_is_held(&graph_lock));
5154 
5155         /* Nothing, tell g_show to print all functions are enabled */
5156         if (ftrace_hash_empty(fgd->hash) && !*pos)
5157                 return FTRACE_GRAPH_EMPTY;
5158 
5159         fgd->idx = 0;
5160         fgd->entry = NULL;
5161         return __g_next(m, pos);
5162 }
5163 
5164 static void g_stop(struct seq_file *m, void *p)
5165 {
5166         mutex_unlock(&graph_lock);
5167 }
5168 
5169 static int g_show(struct seq_file *m, void *v)
5170 {
5171         struct ftrace_func_entry *entry = v;
5172 
5173         if (!entry)
5174                 return 0;
5175 
5176         if (entry == FTRACE_GRAPH_EMPTY) {
5177                 struct ftrace_graph_data *fgd = m->private;
5178 
5179                 if (fgd->type == GRAPH_FILTER_FUNCTION)
5180                         seq_puts(m, "#### all functions enabled ####\n");
5181                 else
5182                         seq_puts(m, "#### no functions disabled ####\n");
5183                 return 0;
5184         }
5185 
5186         seq_printf(m, "%ps\n", (void *)entry->ip);
5187 
5188         return 0;
5189 }
5190 
5191 static const struct seq_operations ftrace_graph_seq_ops = {
5192         .start = g_start,
5193         .next = g_next,
5194         .stop = g_stop,
5195         .show = g_show,
5196 };
5197 
5198 static int
5199 __ftrace_graph_open(struct inode *inode, struct file *file,
5200                     struct ftrace_graph_data *fgd)
5201 {
5202         int ret = 0;
5203         struct ftrace_hash *new_hash = NULL;
5204 
5205         if (file->f_mode & FMODE_WRITE) {
5206                 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5207 
5208                 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5209                         return -ENOMEM;
5210 
5211                 if (file->f_flags & O_TRUNC)
5212                         new_hash = alloc_ftrace_hash(size_bits);
5213                 else
5214                         new_hash = alloc_and_copy_ftrace_hash(size_bits,
5215                                                               fgd->hash);
5216                 if (!new_hash) {
5217                         ret = -ENOMEM;
5218                         goto out;
5219                 }
5220         }
5221 
5222         if (file->f_mode & FMODE_READ) {
5223                 ret = seq_open(file, &ftrace_graph_seq_ops);
5224                 if (!ret) {
5225                         struct seq_file *m = file->private_data;
5226                         m->private = fgd;
5227                 } else {
5228                         /* Failed */
5229                         free_ftrace_hash(new_hash);
5230                         new_hash = NULL;
5231                 }
5232         } else
5233                 file->private_data = fgd;
5234 
5235 out:
5236         if (ret < 0 && file->f_mode & FMODE_WRITE)
5237                 trace_parser_put(&fgd->parser);
5238 
5239         fgd->new_hash = new_hash;
5240 
5241         /*
5242          * All uses of fgd->hash must be taken with the graph_lock
5243          * held. The graph_lock is going to be released, so force
5244          * fgd->hash to be reinitialized when it is taken again.
5245          */
5246         fgd->hash = NULL;
5247 
5248         return ret;
5249 }
5250 
5251 static int
5252 ftrace_graph_open(struct inode *inode, struct file *file)
5253 {
5254         struct ftrace_graph_data *fgd;
5255         int ret;
5256 
5257         if (unlikely(ftrace_disabled))
5258                 return -ENODEV;
5259 
5260         fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5261         if (fgd == NULL)
5262                 return -ENOMEM;
5263 
5264         mutex_lock(&graph_lock);
5265 
5266         fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5267                                         lockdep_is_held(&graph_lock));
5268         fgd->type = GRAPH_FILTER_FUNCTION;
5269         fgd->seq_ops = &ftrace_graph_seq_ops;
5270 
5271         ret = __ftrace_graph_open(inode, file, fgd);
5272         if (ret < 0)
5273                 kfree(fgd);
5274 
5275         mutex_unlock(&graph_lock);
5276         return ret;
5277 }
5278 
5279 static int
5280 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5281 {
5282         struct ftrace_graph_data *fgd;
5283         int ret;
5284 
5285         if (unlikely(ftrace_disabled))
5286                 return -ENODEV;
5287 
5288         fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5289         if (fgd == NULL)
5290                 return -ENOMEM;
5291 
5292         mutex_lock(&graph_lock);
5293 
5294         fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5295                                         lockdep_is_held(&graph_lock));
5296         fgd->type = GRAPH_FILTER_NOTRACE;
5297         fgd->seq_ops = &ftrace_graph_seq_ops;
5298 
5299         ret = __ftrace_graph_open(inode, file, fgd);
5300         if (ret < 0)
5301                 kfree(fgd);
5302 
5303         mutex_unlock(&graph_lock);
5304         return ret;
5305 }
5306 
5307 static int
5308 ftrace_graph_release(struct inode *inode, struct file *file)
5309 {
5310         struct ftrace_graph_data *fgd;
5311         struct ftrace_hash *old_hash, *new_hash;
5312         struct trace_parser *parser;
5313         int ret = 0;
5314 
5315         if (file->f_mode & FMODE_READ) {
5316                 struct seq_file *m = file->private_data;
5317 
5318                 fgd = m->private;
5319                 seq_release(inode, file);
5320         } else {
5321                 fgd = file->private_data;
5322         }
5323 
5324 
5325         if (file->f_mode & FMODE_WRITE) {
5326 
5327                 parser = &fgd->parser;
5328 
5329                 if (trace_parser_loaded((parser))) {
5330                         ret = ftrace_graph_set_hash(fgd->new_hash,
5331                                                     parser->buffer);
5332                 }
5333 
5334                 trace_parser_put(parser);
5335 
5336                 new_hash = __ftrace_hash_move(fgd->new_hash);
5337                 if (!new_hash) {
5338                         ret = -ENOMEM;
5339                         goto out;
5340                 }
5341 
5342                 mutex_lock(&graph_lock);
5343 
5344                 if (fgd->type == GRAPH_FILTER_FUNCTION) {
5345                         old_hash = rcu_dereference_protected(ftrace_graph_hash,
5346                                         lockdep_is_held(&graph_lock));
5347                         rcu_assign_pointer(ftrace_graph_hash, new_hash);
5348                 } else {
5349                         old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5350                                         lockdep_is_held(&graph_lock));
5351                         rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5352                 }
5353 
5354                 mutex_unlock(&graph_lock);
5355 
5356                 /* Wait till all users are no longer using the old hash */
5357                 synchronize_sched();
5358 
5359                 free_ftrace_hash(old_hash);
5360         }
5361 
5362  out:
5363         free_ftrace_hash(fgd->new_hash);
5364         kfree(fgd);
5365 
5366         return ret;
5367 }
5368 
5369 static int
5370 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5371 {
5372         struct ftrace_glob func_g;
5373         struct dyn_ftrace *rec;
5374         struct ftrace_page *pg;
5375         struct ftrace_func_entry *entry;
5376         int fail = 1;
5377         int not;
5378 
5379         /* decode regex */
5380         func_g.type = filter_parse_regex(buffer, strlen(buffer),
5381                                          &func_g.search, &not);
5382 
5383         func_g.len = strlen(func_g.search);
5384 
5385         mutex_lock(&ftrace_lock);
5386 
5387         if (unlikely(ftrace_disabled)) {
5388                 mutex_unlock(&ftrace_lock);
5389                 return -ENODEV;
5390         }
5391 
5392         do_for_each_ftrace_rec(pg, rec) {
5393 
5394                 if (rec->flags & FTRACE_FL_DISABLED)
5395                         continue;
5396 
5397                 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5398                         entry = ftrace_lookup_ip(hash, rec->ip);
5399 
5400                         if (!not) {
5401                                 fail = 0;
5402 
5403                                 if (entry)
5404                                         continue;
5405                                 if (add_hash_entry(hash, rec->ip) < 0)
5406                                         goto out;
5407                         } else {
5408                                 if (entry) {
5409                                         free_hash_entry(hash, entry);
5410                                         fail = 0;
5411                                 }
5412                         }
5413                 }
5414         } while_for_each_ftrace_rec();
5415 out:
5416         mutex_unlock(&ftrace_lock);
5417 
5418         if (fail)
5419                 return -EINVAL;
5420 
5421         return 0;
5422 }
5423 
5424 static ssize_t
5425 ftrace_graph_write(struct file *file, const char __user *ubuf,
5426                    size_t cnt, loff_t *ppos)
5427 {
5428         ssize_t read, ret = 0;
5429         struct ftrace_graph_data *fgd = file->private_data;
5430         struct trace_parser *parser;
5431 
5432         if (!cnt)
5433                 return 0;
5434 
5435         /* Read mode uses seq functions */
5436         if (file->f_mode & FMODE_READ) {
5437                 struct seq_file *m = file->private_data;
5438                 fgd = m->private;
5439         }
5440 
5441         parser = &fgd->parser;
5442 
5443         read = trace_get_user(parser, ubuf, cnt, ppos);
5444 
5445         if (read >= 0 && trace_parser_loaded(parser) &&
5446             !trace_parser_cont(parser)) {
5447 
5448                 ret = ftrace_graph_set_hash(fgd->new_hash,
5449                                             parser->buffer);
5450                 trace_parser_clear(parser);
5451         }
5452 
5453         if (!ret)
5454                 ret = read;
5455 
5456         return ret;
5457 }
5458 
5459 static const struct file_operations ftrace_graph_fops = {
5460         .open           = ftrace_graph_open,
5461         .read           = seq_read,
5462         .write          = ftrace_graph_write,
5463         .llseek         = tracing_lseek,
5464         .release        = ftrace_graph_release,
5465 };
5466 
5467 static const struct file_operations ftrace_graph_notrace_fops = {
5468         .open           = ftrace_graph_notrace_open,
5469         .read           = seq_read,
5470         .write          = ftrace_graph_write,
5471         .llseek         = tracing_lseek,
5472         .release        = ftrace_graph_release,
5473 };
5474 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5475 
5476 void ftrace_create_filter_files(struct ftrace_ops *ops,
5477                                 struct dentry *parent)
5478 {
5479 
5480         trace_create_file("set_ftrace_filter", 0644, parent,
5481                           ops, &ftrace_filter_fops);
5482 
5483         trace_create_file("set_ftrace_notrace", 0644, parent,
5484                           ops, &ftrace_notrace_fops);
5485 }
5486 
5487 /*
5488  * The name "destroy_filter_files" is really a misnomer. Although
5489  * in the future, it may actualy delete the files, but this is
5490  * really intended to make sure the ops passed in are disabled
5491  * and that when this function returns, the caller is free to
5492  * free the ops.
5493  *
5494  * The "destroy" name is only to match the "create" name that this
5495  * should be paired with.
5496  */
5497 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5498 {
5499         mutex_lock(&ftrace_lock);
5500         if (ops->flags & FTRACE_OPS_FL_ENABLED)
5501                 ftrace_shutdown(ops, 0);
5502         ops->flags |= FTRACE_OPS_FL_DELETED;
5503         mutex_unlock(&ftrace_lock);
5504 }
5505 
5506 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5507 {
5508 
5509         trace_create_file("available_filter_functions", 0444,
5510                         d_tracer, NULL, &ftrace_avail_fops);
5511 
5512         trace_create_file("enabled_functions", 0444,
5513                         d_tracer, NULL, &ftrace_enabled_fops);
5514 
5515         ftrace_create_filter_files(&global_ops, d_tracer);
5516 
5517 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5518         trace_create_file("set_graph_function", 0444, d_tracer,
5519                                     NULL,
5520                                     &ftrace_graph_fops);
5521         trace_create_file("set_graph_notrace", 0444, d_tracer,
5522                                     NULL,
5523                                     &ftrace_graph_notrace_fops);
5524 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5525 
5526         return 0;
5527 }
5528 
5529 static int ftrace_cmp_ips(const void *a, const void *b)
5530 {
5531         const unsigned long *ipa = a;
5532         const unsigned long *ipb = b;
5533 
5534         if (*ipa > *ipb)
5535                 return 1;
5536         if (*ipa < *ipb)
5537                 return -1;
5538         return 0;
5539 }
5540 
5541 static int ftrace_process_locs(struct module *mod,
5542                                unsigned long *start,
5543                                unsigned long *end)
5544 {
5545         struct ftrace_page *start_pg;
5546         struct ftrace_page *pg;
5547         struct dyn_ftrace *rec;
5548         unsigned long count;
5549         unsigned long *p;
5550         unsigned long addr;
5551         unsigned long flags = 0; /* Shut up gcc */
5552         int ret = -ENOMEM;
5553 
5554         count = end - start;
5555 
5556         if (!count)
5557                 return 0;
5558 
5559         sort(start, count, sizeof(*start),
5560              ftrace_cmp_ips, NULL);
5561 
5562         start_pg = ftrace_allocate_pages(count);
5563         if (!start_pg)
5564                 return -ENOMEM;
5565 
5566         mutex_lock(&ftrace_lock);
5567 
5568         /*
5569          * Core and each module needs their own pages, as
5570          * modules will free them when they are removed.
5571          * Force a new page to be allocated for modules.
5572          */
5573         if (!mod) {
5574                 WARN_ON(ftrace_pages || ftrace_pages_start);
5575                 /* First initialization */
5576                 ftrace_pages = ftrace_pages_start = start_pg;
5577         } else {
5578                 if (!ftrace_pages)
5579                         goto out;
5580 
5581                 if (WARN_ON(ftrace_pages->next)) {
5582                         /* Hmm, we have free pages? */
5583                         while (ftrace_pages->next)
5584                                 ftrace_pages = ftrace_pages->next;
5585                 }
5586 
5587                 ftrace_pages->next = start_pg;
5588         }
5589 
5590         p = start;
5591         pg = start_pg;
5592         while (p < end) {
5593                 addr = ftrace_call_adjust(*p++);
5594                 /*
5595                  * Some architecture linkers will pad between
5596                  * the different mcount_loc sections of different
5597                  * object files to satisfy alignments.
5598                  * Skip any NULL pointers.
5599                  */
5600                 if (!addr)
5601                         continue;
5602 
5603                 if (pg->index == pg->size) {
5604                         /* We should have allocated enough */
5605                         if (WARN_ON(!pg->next))
5606                                 break;
5607                         pg = pg->next;
5608                 }
5609 
5610                 rec = &pg->records[pg->index++];
5611                 rec->ip = addr;
5612         }
5613 
5614         /* We should have used all pages */
5615         WARN_ON(pg->next);
5616 
5617         /* Assign the last page to ftrace_pages */
5618         ftrace_pages = pg;
5619 
5620         /*
5621          * We only need to disable interrupts on start up
5622          * because we are modifying code that an interrupt
5623          * may execute, and the modification is not atomic.
5624          * But for modules, nothing runs the code we modify
5625          * until we are finished with it, and there's no
5626          * reason to cause large interrupt latencies while we do it.
5627          */
5628         if (!mod)
5629                 local_irq_save(flags);
5630         ftrace_update_code(mod, start_pg);
5631         if (!mod)
5632                 local_irq_restore(flags);
5633         ret = 0;
5634  out:
5635         mutex_unlock(&ftrace_lock);
5636 
5637         return ret;
5638 }
5639 
5640 struct ftrace_mod_func {
5641         struct list_head        list;
5642         char                    *name;
5643         unsigned long           ip;
5644         unsigned int            size;
5645 };
5646 
5647 struct ftrace_mod_map {
5648         struct rcu_head         rcu;
5649         struct list_head        list;
5650         struct module           *mod;
5651         unsigned long           start_addr;
5652         unsigned long           end_addr;
5653         struct list_head        funcs;
5654         unsigned int            num_funcs;
5655 };
5656 
5657 #ifdef CONFIG_MODULES
5658 
5659 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5660 
5661 static LIST_HEAD(ftrace_mod_maps);
5662 
5663 static int referenced_filters(struct dyn_ftrace *rec)
5664 {
5665         struct ftrace_ops *ops;
5666         int cnt = 0;
5667 
5668         for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5669                 if (ops_references_rec(ops, rec))
5670                     cnt++;
5671         }
5672 
5673         return cnt;
5674 }
5675 
5676 static void
5677 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5678 {
5679         struct ftrace_func_entry *entry;
5680         struct dyn_ftrace *rec;
5681         int i;
5682 
5683         if (ftrace_hash_empty(hash))
5684                 return;
5685 
5686         for (i = 0; i < pg->index; i++) {
5687                 rec = &pg->records[i];
5688                 entry = __ftrace_lookup_ip(hash, rec->ip);
5689                 /*
5690                  * Do not allow this rec to match again.
5691                  * Yeah, it may waste some memory, but will be removed
5692                  * if/when the hash is modified again.
5693                  */
5694                 if (entry)
5695                         entry->ip = 0;
5696         }
5697 }
5698 
5699 /* Clear any records from hashs */
5700 static void clear_mod_from_hashes(struct ftrace_page *pg)
5701 {
5702         struct trace_array *tr;
5703 
5704         mutex_lock(&trace_types_lock);
5705         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5706                 if (!tr->ops || !tr->ops->func_hash)
5707                         continue;
5708                 mutex_lock(&tr->ops->func_hash->regex_lock);
5709                 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5710                 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5711                 mutex_unlock(&tr->ops->func_hash->regex_lock);
5712         }
5713         mutex_unlock(&trace_types_lock);
5714 }
5715 
5716 static void ftrace_free_mod_map(struct rcu_head *rcu)
5717 {
5718         struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
5719         struct ftrace_mod_func *mod_func;
5720         struct ftrace_mod_func *n;
5721 
5722         /* All the contents of mod_map are now not visible to readers */
5723         list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
5724                 kfree(mod_func->name);
5725                 list_del(&mod_func->list);
5726                 kfree(mod_func);
5727         }
5728 
5729         kfree(mod_map);
5730 }
5731 
5732 void ftrace_release_mod(struct module *mod)
5733 {
5734         struct ftrace_mod_map *mod_map;
5735         struct ftrace_mod_map *n;
5736         struct dyn_ftrace *rec;
5737         struct ftrace_page **last_pg;
5738         struct ftrace_page *tmp_page = NULL;
5739         struct ftrace_page *pg;
5740         int order;
5741 
5742         mutex_lock(&ftrace_lock);
5743 
5744         if (ftrace_disabled)
5745                 goto out_unlock;
5746 
5747         list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
5748                 if (mod_map->mod == mod) {
5749                         list_del_rcu(&mod_map->list);
5750                         call_rcu_sched(&mod_map->rcu, ftrace_free_mod_map);
5751                         break;
5752                 }
5753         }
5754 
5755         /*
5756          * Each module has its own ftrace_pages, remove
5757          * them from the list.
5758          */
5759         last_pg = &ftrace_pages_start;
5760         for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5761                 rec = &pg->records[0];
5762                 if (within_module_core(rec->ip, mod) ||
5763                     within_module_init(rec->ip, mod)) {
5764                         /*
5765                          * As core pages are first, the first
5766                          * page should never be a module page.
5767                          */
5768                         if (WARN_ON(pg == ftrace_pages_start))
5769                                 goto out_unlock;
5770 
5771                         /* Check if we are deleting the last page */
5772                         if (pg == ftrace_pages)
5773                                 ftrace_pages = next_to_ftrace_page(last_pg);
5774 
5775                         ftrace_update_tot_cnt -= pg->index;
5776                         *last_pg = pg->next;
5777 
5778                         pg->next = tmp_page;
5779                         tmp_page = pg;
5780                 } else
5781                         last_pg = &pg->next;
5782         }
5783  out_unlock:
5784         mutex_unlock(&ftrace_lock);
5785 
5786         for (pg = tmp_page; pg; pg = tmp_page) {
5787 
5788                 /* Needs to be called outside of ftrace_lock */
5789                 clear_mod_from_hashes(pg);
5790 
5791                 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5792                 free_pages((unsigned long)pg->records, order);
5793                 tmp_page = pg->next;
5794                 kfree(pg);
5795         }
5796 }
5797 
5798 void ftrace_module_enable(struct module *mod)
5799 {
5800         struct dyn_ftrace *rec;
5801         struct ftrace_page *pg;
5802 
5803         mutex_lock(&ftrace_lock);
5804 
5805         if (ftrace_disabled)
5806                 goto out_unlock;
5807 
5808         /*
5809          * If the tracing is enabled, go ahead and enable the record.
5810          *
5811          * The reason not to enable the record immediatelly is the
5812          * inherent check of ftrace_make_nop/ftrace_make_call for
5813          * correct previous instructions.  Making first the NOP
5814          * conversion puts the module to the correct state, thus
5815          * passing the ftrace_make_call check.
5816          *
5817          * We also delay this to after the module code already set the
5818          * text to read-only, as we now need to set it back to read-write
5819          * so that we can modify the text.
5820          */
5821         if (ftrace_start_up)
5822                 ftrace_arch_code_modify_prepare();
5823 
5824         do_for_each_ftrace_rec(pg, rec) {
5825                 int cnt;
5826                 /*
5827                  * do_for_each_ftrace_rec() is a double loop.
5828                  * module text shares the pg. If a record is
5829                  * not part of this module, then skip this pg,
5830                  * which the "break" will do.
5831                  */
5832                 if (!within_module_core(rec->ip, mod) &&
5833                     !within_module_init(rec->ip, mod))
5834                         break;
5835 
5836                 cnt = 0;
5837 
5838                 /*
5839                  * When adding a module, we need to check if tracers are
5840                  * currently enabled and if they are, and can trace this record,
5841                  * we need to enable the module functions as well as update the
5842                  * reference counts for those function records.
5843                  */
5844                 if (ftrace_start_up)
5845                         cnt += referenced_filters(rec);
5846 
5847                 /* This clears FTRACE_FL_DISABLED */
5848                 rec->flags = cnt;
5849 
5850                 if (ftrace_start_up && cnt) {
5851                         int failed = __ftrace_replace_code(rec, 1);
5852                         if (failed) {
5853                                 ftrace_bug(failed, rec);
5854                                 goto out_loop;
5855                         }
5856                 }
5857 
5858         } while_for_each_ftrace_rec();
5859 
5860  out_loop:
5861         if (ftrace_start_up)
5862                 ftrace_arch_code_modify_post_process();
5863 
5864  out_unlock:
5865         mutex_unlock(&ftrace_lock);
5866 
5867         process_cached_mods(mod->name);
5868 }
5869 
5870 void ftrace_module_init(struct module *mod)
5871 {
5872         if (ftrace_disabled || !mod->num_ftrace_callsites)
5873                 return;
5874 
5875         ftrace_process_locs(mod, mod->ftrace_callsites,
5876                             mod->ftrace_callsites + mod->num_ftrace_callsites);
5877 }
5878 
5879 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
5880                                 struct dyn_ftrace *rec)
5881 {
5882         struct ftrace_mod_func *mod_func;
5883         unsigned long symsize;
5884         unsigned long offset;
5885         char str[KSYM_SYMBOL_LEN];
5886         char *modname;
5887         const char *ret;
5888 
5889         ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
5890         if (!ret)
5891                 return;
5892 
5893         mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
5894         if (!mod_func)
5895                 return;
5896 
5897         mod_func->name = kstrdup(str, GFP_KERNEL);
5898         if (!mod_func->name) {
5899                 kfree(mod_func);
5900                 return;
5901         }
5902 
5903         mod_func->ip = rec->ip - offset;
5904         mod_func->size = symsize;
5905 
5906         mod_map->num_funcs++;
5907 
5908         list_add_rcu(&mod_func->list, &mod_map->funcs);
5909 }
5910 
5911 static struct ftrace_mod_map *
5912 allocate_ftrace_mod_map(struct module *mod,
5913                         unsigned long start, unsigned long end)
5914 {
5915         struct ftrace_mod_map *mod_map;
5916 
5917         mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
5918         if (!mod_map)
5919                 return NULL;
5920 
5921         mod_map->mod = mod;
5922         mod_map->start_addr = start;
5923         mod_map->end_addr = end;
5924         mod_map->num_funcs = 0;
5925 
5926         INIT_LIST_HEAD_RCU(&mod_map->funcs);
5927 
5928         list_add_rcu(&mod_map->list, &ftrace_mod_maps);
5929 
5930         return mod_map;
5931 }
5932 
5933 static const char *
5934 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
5935                            unsigned long addr, unsigned long *size,
5936                            unsigned long *off, char *sym)
5937 {
5938         struct ftrace_mod_func *found_func =  NULL;
5939         struct ftrace_mod_func *mod_func;
5940 
5941         list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
5942                 if (addr >= mod_func->ip &&
5943                     addr < mod_func->ip + mod_func->size) {
5944                         found_func = mod_func;
5945                         break;
5946                 }
5947         }
5948 
5949         if (found_func) {
5950                 if (size)
5951                         *size = found_func->size;
5952                 if (off)
5953                         *off = addr - found_func->ip;
5954                 if (sym)
5955                         strlcpy(sym, found_func->name, KSYM_NAME_LEN);
5956 
5957                 return found_func->name;
5958         }
5959 
5960         return NULL;
5961 }
5962 
5963 const char *
5964 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
5965                    unsigned long *off, char **modname, char *sym)
5966 {
5967         struct ftrace_mod_map *mod_map;
5968         const char *ret = NULL;
5969 
5970         /* mod_map is freed via call_rcu_sched() */
5971         preempt_disable();
5972         list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5973                 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
5974                 if (ret) {
5975                         if (modname)
5976                                 *modname = mod_map->mod->name;
5977                         break;
5978                 }
5979         }
5980         preempt_enable();
5981 
5982         return ret;
5983 }
5984 
5985 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
5986                            char *type, char *name,
5987                            char *module_name, int *exported)
5988 {
5989         struct ftrace_mod_map *mod_map;
5990         struct ftrace_mod_func *mod_func;
5991 
5992         preempt_disable();
5993         list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5994 
5995                 if (symnum >= mod_map->num_funcs) {
5996                         symnum -= mod_map->num_funcs;
5997                         continue;
5998                 }
5999 
6000                 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6001                         if (symnum > 1) {
6002                                 symnum--;
6003                                 continue;
6004                         }
6005 
6006                         *value = mod_func->ip;
6007                         *type = 'T';
6008                         strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6009                         strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6010                         *exported = 1;
6011                         preempt_enable();
6012                         return 0;
6013                 }
6014                 WARN_ON(1);
6015                 break;
6016         }
6017         preempt_enable();
6018         return -ERANGE;
6019 }
6020 
6021 #else
6022 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6023                                 struct dyn_ftrace *rec) { }
6024 static inline struct ftrace_mod_map *
6025 allocate_ftrace_mod_map(struct module *mod,
6026                         unsigned long start, unsigned long end)
6027 {
6028         return NULL;
6029 }
6030 #endif /* CONFIG_MODULES */
6031 
6032 struct ftrace_init_func {
6033         struct list_head list;
6034         unsigned long ip;
6035 };
6036 
6037 /* Clear any init ips from hashes */
6038 static void
6039 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6040 {
6041         struct ftrace_func_entry *entry;
6042 
6043         if (ftrace_hash_empty(hash))
6044                 return;
6045 
6046         entry = __ftrace_lookup_ip(hash, func->ip);
6047 
6048         /*
6049          * Do not allow this rec to match again.
6050          * Yeah, it may waste some memory, but will be removed
6051          * if/when the hash is modified again.
6052          */
6053         if (entry)
6054                 entry->ip = 0;
6055 }
6056 
6057 static void
6058 clear_func_from_hashes(struct ftrace_init_func *func)
6059 {
6060         struct trace_array *tr;
6061 
6062         mutex_lock(&trace_types_lock);
6063         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6064                 if (!tr->ops || !tr->ops->func_hash)
6065                         continue;
6066                 mutex_lock(&tr->ops->func_hash->regex_lock);
6067                 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6068                 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6069                 mutex_unlock(&tr->ops->func_hash->regex_lock);
6070         }
6071         mutex_unlock(&trace_types_lock);
6072 }
6073 
6074 static void add_to_clear_hash_list(struct list_head *clear_list,
6075                                    struct dyn_ftrace *rec)
6076 {
6077         struct ftrace_init_func *func;
6078 
6079         func = kmalloc(sizeof(*func), GFP_KERNEL);
6080         if (!func) {
6081                 WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6082                 return;
6083         }
6084 
6085         func->ip = rec->ip;
6086         list_add(&func->list, clear_list);
6087 }
6088 
6089 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6090 {
6091         unsigned long start = (unsigned long)(start_ptr);
6092         unsigned long end = (unsigned long)(end_ptr);
6093         struct ftrace_page **last_pg = &ftrace_pages_start;
6094         struct ftrace_page *pg;
6095         struct dyn_ftrace *rec;
6096         struct dyn_ftrace key;
6097         struct ftrace_mod_map *mod_map = NULL;
6098         struct ftrace_init_func *func, *func_next;
6099         struct list_head clear_hash;
6100         int order;
6101 
6102         INIT_LIST_HEAD(&clear_hash);
6103 
6104         key.ip = start;
6105         key.flags = end;        /* overload flags, as it is unsigned long */
6106 
6107         mutex_lock(&ftrace_lock);
6108 
6109         /*
6110          * If we are freeing module init memory, then check if
6111          * any tracer is active. If so, we need to save a mapping of
6112          * the module functions being freed with the address.
6113          */
6114         if (mod && ftrace_ops_list != &ftrace_list_end)
6115                 mod_map = allocate_ftrace_mod_map(mod, start, end);
6116 
6117         for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6118                 if (end < pg->records[0].ip ||
6119                     start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6120                         continue;
6121  again:
6122                 rec = bsearch(&key, pg->records, pg->index,
6123                               sizeof(struct dyn_ftrace),
6124                               ftrace_cmp_recs);
6125                 if (!rec)
6126                         continue;
6127 
6128                 /* rec will be cleared from hashes after ftrace_lock unlock */
6129                 add_to_clear_hash_list(&clear_hash, rec);
6130 
6131                 if (mod_map)
6132                         save_ftrace_mod_rec(mod_map, rec);
6133 
6134                 pg->index--;
6135                 ftrace_update_tot_cnt--;
6136                 if (!pg->index) {
6137                         *last_pg = pg->next;
6138                         order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6139                         free_pages((unsigned long)pg->records, order);
6140                         kfree(pg);
6141                         pg = container_of(last_pg, struct ftrace_page, next);
6142                         if (!(*last_pg))
6143                                 ftrace_pages = pg;
6144                         continue;
6145                 }
6146                 memmove(rec, rec + 1,
6147                         (pg->index - (rec - pg->records)) * sizeof(*rec));
6148                 /* More than one function may be in this block */
6149                 goto again;
6150         }
6151         mutex_unlock(&ftrace_lock);
6152 
6153         list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6154                 clear_func_from_hashes(func);
6155                 kfree(func);
6156         }
6157 }
6158 
6159 void __init ftrace_free_init_mem(void)
6160 {
6161         void *start = (void *)(&__init_begin);
6162         void *end = (void *)(&__init_end);
6163 
6164         ftrace_free_mem(NULL, start, end);
6165 }
6166 
6167 void __init ftrace_init(void)
6168 {
6169         extern unsigned long __start_mcount_loc[];
6170         extern unsigned long __stop_mcount_loc[];
6171         unsigned long count, flags;
6172         int ret;
6173 
6174         local_irq_save(flags);
6175         ret = ftrace_dyn_arch_init();
6176         local_irq_restore(flags);
6177         if (ret)
6178                 goto failed;
6179 
6180         count = __stop_mcount_loc - __start_mcount_loc;
6181         if (!count) {
6182                 pr_info("ftrace: No functions to be traced?\n");
6183                 goto failed;
6184         }
6185 
6186         pr_info("ftrace: allocating %ld entries in %ld pages\n",
6187                 count, count / ENTRIES_PER_PAGE + 1);
6188 
6189         last_ftrace_enabled = ftrace_enabled = 1;
6190 
6191         ret = ftrace_process_locs(NULL,
6192                                   __start_mcount_loc,
6193                                   __stop_mcount_loc);
6194 
6195         set_ftrace_early_filters();
6196 
6197         return;
6198  failed:
6199         ftrace_disabled = 1;
6200 }
6201 
6202 /* Do nothing if arch does not support this */
6203 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6204 {
6205 }
6206 
6207 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6208 {
6209         arch_ftrace_update_trampoline(ops);
6210 }
6211 
6212 void ftrace_init_trace_array(struct trace_array *tr)
6213 {
6214         INIT_LIST_HEAD(&tr->func_probes);
6215         INIT_LIST_HEAD(&tr->mod_trace);
6216         INIT_LIST_HEAD(&tr->mod_notrace);
6217 }
6218 #else
6219 
6220 static struct ftrace_ops global_ops = {
6221         .func                   = ftrace_stub,
6222         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE |
6223                                   FTRACE_OPS_FL_INITIALIZED |
6224                                   FTRACE_OPS_FL_PID,
6225 };
6226 
6227 static int __init ftrace_nodyn_init(void)
6228 {
6229         ftrace_enabled = 1;
6230         return 0;
6231 }
6232 core_initcall(ftrace_nodyn_init);
6233 
6234 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6235 static inline void ftrace_startup_enable(int command) { }
6236 static inline void ftrace_startup_all(int command) { }
6237 /* Keep as macros so we do not need to define the commands */
6238 # define ftrace_startup(ops, command)                                   \
6239         ({                                                              \
6240                 int ___ret = __register_ftrace_function(ops);           \
6241                 if (!___ret)                                            \
6242                         (ops)->flags |= FTRACE_OPS_FL_ENABLED;          \
6243                 ___ret;                                                 \
6244         })
6245 # define ftrace_shutdown(ops, command)                                  \
6246         ({                                                              \
6247                 int ___ret = __unregister_ftrace_function(ops);         \
6248                 if (!___ret)                                            \
6249                         (ops)->flags &= ~FTRACE_OPS_FL_ENABLED;         \
6250                 ___ret;                                                 \
6251         })
6252 
6253 # define ftrace_startup_sysctl()        do { } while (0)
6254 # define ftrace_shutdown_sysctl()       do { } while (0)
6255 
6256 static inline int
6257 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
6258 {
6259         return 1;
6260 }
6261 
6262 static void ftrace_update_trampoline(struct ftrace_ops *ops)
6263 {
6264 }
6265 
6266 #endif /* CONFIG_DYNAMIC_FTRACE */
6267 
6268 __init void ftrace_init_global_array_ops(struct trace_array *tr)
6269 {
6270         tr->ops = &global_ops;
6271         tr->ops->private = tr;
6272         ftrace_init_trace_array(tr);
6273 }
6274 
6275 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6276 {
6277         /* If we filter on pids, update to use the pid function */
6278         if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6279                 if (WARN_ON(tr->ops->func != ftrace_stub))
6280                         printk("ftrace ops had %pS for function\n",
6281                                tr->ops->func);
6282         }
6283         tr->ops->func = func;
6284         tr->ops->private = tr;
6285 }
6286 
6287 void ftrace_reset_array_ops(struct trace_array *tr)
6288 {
6289         tr->ops->func = ftrace_stub;
6290 }
6291 
6292 static inline void
6293 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6294                        struct ftrace_ops *ignored, struct pt_regs *regs)
6295 {
6296         struct ftrace_ops *op;
6297         int bit;
6298 
6299         bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6300         if (bit < 0)
6301                 return;
6302 
6303         /*
6304          * Some of the ops may be dynamically allocated,
6305          * they must be freed after a synchronize_sched().
6306          */
6307         preempt_disable_notrace();
6308 
6309         do_for_each_ftrace_op(op, ftrace_ops_list) {
6310                 /*
6311                  * Check the following for each ops before calling their func:
6312                  *  if RCU flag is set, then rcu_is_watching() must be true
6313                  *  if PER_CPU is set, then ftrace_function_local_disable()
6314                  *                          must be false
6315                  *  Otherwise test if the ip matches the ops filter
6316                  *
6317                  * If any of the above fails then the op->func() is not executed.
6318                  */
6319                 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6320                     ftrace_ops_test(op, ip, regs)) {
6321                         if (FTRACE_WARN_ON(!op->func)) {
6322                                 pr_warn("op=%p %pS\n", op, op);
6323                                 goto out;
6324                         }
6325                         op->func(ip, parent_ip, op, regs);
6326                 }
6327         } while_for_each_ftrace_op(op);
6328 out:
6329         preempt_enable_notrace();
6330         trace_clear_recursion(bit);
6331 }
6332 
6333 /*
6334  * Some archs only support passing ip and parent_ip. Even though
6335  * the list function ignores the op parameter, we do not want any
6336  * C side effects, where a function is called without the caller
6337  * sending a third parameter.
6338  * Archs are to support both the regs and ftrace_ops at the same time.
6339  * If they support ftrace_ops, it is assumed they support regs.
6340  * If call backs want to use regs, they must either check for regs
6341  * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6342  * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6343  * An architecture can pass partial regs with ftrace_ops and still
6344  * set the ARCH_SUPPORTS_FTRACE_OPS.
6345  */
6346 #if ARCH_SUPPORTS_FTRACE_OPS
6347 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6348                                  struct ftrace_ops *op, struct pt_regs *regs)
6349 {
6350         __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6351 }
6352 #else
6353 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6354 {
6355         __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6356 }
6357 #endif
6358 
6359 /*
6360  * If there's only one function registered but it does not support
6361  * recursion, needs RCU protection and/or requires per cpu handling, then
6362  * this function will be called by the mcount trampoline.
6363  */
6364 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6365                                    struct ftrace_ops *op, struct pt_regs *regs)
6366 {
6367         int bit;
6368 
6369         if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6370                 return;
6371 
6372         bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6373         if (bit < 0)
6374                 return;
6375 
6376         preempt_disable_notrace();
6377 
6378         op->func(ip, parent_ip, op, regs);
6379 
6380         preempt_enable_notrace();
6381         trace_clear_recursion(bit);
6382 }
6383 
6384 /**
6385  * ftrace_ops_get_func - get the function a trampoline should call
6386  * @ops: the ops to get the function for
6387  *
6388  * Normally the mcount trampoline will call the ops->func, but there
6389  * are times that it should not. For example, if the ops does not
6390  * have its own recursion protection, then it should call the
6391  * ftrace_ops_assist_func() instead.
6392  *
6393  * Returns the function that the trampoline should call for @ops.
6394  */
6395 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6396 {
6397         /*
6398          * If the function does not handle recursion, needs to be RCU safe,
6399          * or does per cpu logic, then we need to call the assist handler.
6400          */
6401         if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6402             ops->flags & FTRACE_OPS_FL_RCU)
6403                 return ftrace_ops_assist_func;
6404 
6405         return ops->func;
6406 }
6407 
6408 static void
6409 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6410                     struct task_struct *prev, struct task_struct *next)
6411 {
6412         struct trace_array *tr = data;
6413         struct trace_pid_list *pid_list;
6414 
6415         pid_list = rcu_dereference_sched(tr->function_pids);
6416 
6417         this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6418                        trace_ignore_this_task(pid_list, next));
6419 }
6420 
6421 static void
6422 ftrace_pid_follow_sched_process_fork(void *data,
6423                                      struct task_struct *self,
6424                                      struct task_struct *task)
6425 {
6426         struct trace_pid_list *pid_list;
6427         struct trace_array *tr = data;
6428 
6429         pid_list = rcu_dereference_sched(tr->function_pids);
6430         trace_filter_add_remove_task(pid_list, self, task);
6431 }
6432 
6433 static void
6434 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6435 {
6436         struct trace_pid_list *pid_list;
6437         struct trace_array *tr = data;
6438 
6439         pid_list = rcu_dereference_sched(tr->function_pids);
6440         trace_filter_add_remove_task(pid_list, NULL, task);
6441 }
6442 
6443 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6444 {
6445         if (enable) {
6446                 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6447                                                   tr);
6448                 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6449                                                   tr);
6450         } else {
6451                 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6452                                                     tr);
6453                 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6454                                                     tr);
6455         }
6456 }
6457 
6458 static void clear_ftrace_pids(struct trace_array *tr)
6459 {
6460         struct trace_pid_list *pid_list;
6461         int cpu;
6462 
6463         pid_list = rcu_dereference_protected(tr->function_pids,
6464                                              lockdep_is_held(&ftrace_lock));
6465         if (!pid_list)
6466                 return;
6467 
6468         unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6469 
6470         for_each_possible_cpu(cpu)
6471                 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6472 
6473         rcu_assign_pointer(tr->function_pids, NULL);
6474 
6475         /* Wait till all users are no longer using pid filtering */
6476         synchronize_sched();
6477 
6478         trace_free_pid_list(pid_list);
6479 }
6480 
6481 void ftrace_clear_pids(struct trace_array *tr)
6482 {
6483         mutex_lock(&ftrace_lock);
6484 
6485         clear_ftrace_pids(tr);
6486 
6487         mutex_unlock(&ftrace_lock);
6488 }
6489 
6490 static void ftrace_pid_reset(struct trace_array *tr)
6491 {
6492         mutex_lock(&ftrace_lock);
6493         clear_ftrace_pids(tr);
6494 
6495         ftrace_update_pid_func();
6496         ftrace_startup_all(0);
6497 
6498         mutex_unlock(&ftrace_lock);
6499 }
6500 
6501 /* Greater than any max PID */
6502 #define FTRACE_NO_PIDS          (void *)(PID_MAX_LIMIT + 1)
6503 
6504 static void *fpid_start(struct seq_file *m, loff_t *pos)
6505         __acquires(RCU)
6506 {
6507         struct trace_pid_list *pid_list;
6508         struct trace_array *tr = m->private;
6509 
6510         mutex_lock(&ftrace_lock);
6511         rcu_read_lock_sched();
6512 
6513         pid_list = rcu_dereference_sched(tr->function_pids);
6514 
6515         if (!pid_list)
6516                 return !(*pos) ? FTRACE_NO_PIDS : NULL;
6517 
6518         return trace_pid_start(pid_list, pos);
6519 }
6520 
6521 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6522 {
6523         struct trace_array *tr = m->private;
6524         struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6525 
6526         if (v == FTRACE_NO_PIDS)
6527                 return NULL;
6528 
6529         return trace_pid_next(pid_list, v, pos);
6530 }
6531 
6532 static void fpid_stop(struct seq_file *m, void *p)
6533         __releases(RCU)
6534 {
6535         rcu_read_unlock_sched();
6536         mutex_unlock(&ftrace_lock);
6537 }
6538 
6539 static int fpid_show(struct seq_file *m, void *v)
6540 {
6541         if (v == FTRACE_NO_PIDS) {
6542                 seq_puts(m, "no pid\n");
6543                 return 0;
6544         }
6545 
6546         return trace_pid_show(m, v);
6547 }
6548 
6549 static const struct seq_operations ftrace_pid_sops = {
6550         .start = fpid_start,
6551         .next = fpid_next,
6552         .stop = fpid_stop,
6553         .show = fpid_show,
6554 };
6555 
6556 static int
6557 ftrace_pid_open(struct inode *inode, struct file *file)
6558 {
6559         struct trace_array *tr = inode->i_private;
6560         struct seq_file *m;
6561         int ret = 0;
6562 
6563         if (trace_array_get(tr) < 0)
6564                 return -ENODEV;
6565 
6566         if ((file->f_mode & FMODE_WRITE) &&
6567             (file->f_flags & O_TRUNC))
6568                 ftrace_pid_reset(tr);
6569 
6570         ret = seq_open(file, &ftrace_pid_sops);
6571         if (ret < 0) {
6572                 trace_array_put(tr);
6573         } else {
6574                 m = file->private_data;
6575                 /* copy tr over to seq ops */
6576                 m->private = tr;
6577         }
6578 
6579         return ret;
6580 }
6581 
6582 static void ignore_task_cpu(void *data)
6583 {
6584         struct trace_array *tr = data;
6585         struct trace_pid_list *pid_list;
6586 
6587         /*
6588          * This function is called by on_each_cpu() while the
6589          * event_mutex is held.
6590          */
6591         pid_list = rcu_dereference_protected(tr->function_pids,
6592                                              mutex_is_locked(&ftrace_lock));
6593 
6594         this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6595                        trace_ignore_this_task(pid_list, current));
6596 }
6597 
6598 static ssize_t
6599 ftrace_pid_write(struct file *filp, const char __user *ubuf,
6600                    size_t cnt, loff_t *ppos)
6601 {
6602         struct seq_file *m = filp->private_data;
6603         struct trace_array *tr = m->private;
6604         struct trace_pid_list *filtered_pids = NULL;
6605         struct trace_pid_list *pid_list;
6606