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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/kallsyms.h>
 19 #include <linux/seq_file.h>
 20 #include <linux/suspend.h>
 21 #include <linux/debugfs.h>
 22 #include <linux/hardirq.h>
 23 #include <linux/kthread.h>
 24 #include <linux/uaccess.h>
 25 #include <linux/bsearch.h>
 26 #include <linux/module.h>
 27 #include <linux/ftrace.h>
 28 #include <linux/sysctl.h>
 29 #include <linux/slab.h>
 30 #include <linux/ctype.h>
 31 #include <linux/sort.h>
 32 #include <linux/list.h>
 33 #include <linux/hash.h>
 34 #include <linux/rcupdate.h>
 35 
 36 #include <trace/events/sched.h>
 37 
 38 #include <asm/setup.h>
 39 
 40 #include "trace_output.h"
 41 #include "trace_stat.h"
 42 
 43 #define FTRACE_WARN_ON(cond)                    \
 44         ({                                      \
 45                 int ___r = cond;                \
 46                 if (WARN_ON(___r))              \
 47                         ftrace_kill();          \
 48                 ___r;                           \
 49         })
 50 
 51 #define FTRACE_WARN_ON_ONCE(cond)               \
 52         ({                                      \
 53                 int ___r = cond;                \
 54                 if (WARN_ON_ONCE(___r))         \
 55                         ftrace_kill();          \
 56                 ___r;                           \
 57         })
 58 
 59 /* hash bits for specific function selection */
 60 #define FTRACE_HASH_BITS 7
 61 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
 62 #define FTRACE_HASH_DEFAULT_BITS 10
 63 #define FTRACE_HASH_MAX_BITS 12
 64 
 65 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
 66 
 67 #ifdef CONFIG_DYNAMIC_FTRACE
 68 #define INIT_REGEX_LOCK(opsname)        \
 69         .regex_lock     = __MUTEX_INITIALIZER(opsname.regex_lock),
 70 #else
 71 #define INIT_REGEX_LOCK(opsname)
 72 #endif
 73 
 74 static struct ftrace_ops ftrace_list_end __read_mostly = {
 75         .func           = ftrace_stub,
 76         .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
 77 };
 78 
 79 /* ftrace_enabled is a method to turn ftrace on or off */
 80 int ftrace_enabled __read_mostly;
 81 static int last_ftrace_enabled;
 82 
 83 /* Quick disabling of function tracer. */
 84 int function_trace_stop __read_mostly;
 85 
 86 /* Current function tracing op */
 87 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
 88 
 89 /* List for set_ftrace_pid's pids. */
 90 LIST_HEAD(ftrace_pids);
 91 struct ftrace_pid {
 92         struct list_head list;
 93         struct pid *pid;
 94 };
 95 
 96 /*
 97  * ftrace_disabled is set when an anomaly is discovered.
 98  * ftrace_disabled is much stronger than ftrace_enabled.
 99  */
100 static int ftrace_disabled __read_mostly;
101 
102 static DEFINE_MUTEX(ftrace_lock);
103 
104 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
105 static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
106 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
107 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
108 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
109 static struct ftrace_ops global_ops;
110 static struct ftrace_ops control_ops;
111 
112 #if ARCH_SUPPORTS_FTRACE_OPS
113 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
114                                  struct ftrace_ops *op, struct pt_regs *regs);
115 #else
116 /* See comment below, where ftrace_ops_list_func is defined */
117 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
118 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
119 #endif
120 
121 /*
122  * Traverse the ftrace_global_list, invoking all entries.  The reason that we
123  * can use rcu_dereference_raw_notrace() is that elements removed from this list
124  * are simply leaked, so there is no need to interact with a grace-period
125  * mechanism.  The rcu_dereference_raw_notrace() calls are needed to handle
126  * concurrent insertions into the ftrace_global_list.
127  *
128  * Silly Alpha and silly pointer-speculation compiler optimizations!
129  */
130 #define do_for_each_ftrace_op(op, list)                 \
131         op = rcu_dereference_raw_notrace(list);                 \
132         do
133 
134 /*
135  * Optimized for just a single item in the list (as that is the normal case).
136  */
137 #define while_for_each_ftrace_op(op)                            \
138         while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&  \
139                unlikely((op) != &ftrace_list_end))
140 
141 static inline void ftrace_ops_init(struct ftrace_ops *ops)
142 {
143 #ifdef CONFIG_DYNAMIC_FTRACE
144         if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
145                 mutex_init(&ops->regex_lock);
146                 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
147         }
148 #endif
149 }
150 
151 /**
152  * ftrace_nr_registered_ops - return number of ops registered
153  *
154  * Returns the number of ftrace_ops registered and tracing functions
155  */
156 int ftrace_nr_registered_ops(void)
157 {
158         struct ftrace_ops *ops;
159         int cnt = 0;
160 
161         mutex_lock(&ftrace_lock);
162 
163         for (ops = ftrace_ops_list;
164              ops != &ftrace_list_end; ops = ops->next)
165                 cnt++;
166 
167         mutex_unlock(&ftrace_lock);
168 
169         return cnt;
170 }
171 
172 static void
173 ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
174                         struct ftrace_ops *op, struct pt_regs *regs)
175 {
176         int bit;
177 
178         bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
179         if (bit < 0)
180                 return;
181 
182         do_for_each_ftrace_op(op, ftrace_global_list) {
183                 op->func(ip, parent_ip, op, regs);
184         } while_for_each_ftrace_op(op);
185 
186         trace_clear_recursion(bit);
187 }
188 
189 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
190                             struct ftrace_ops *op, struct pt_regs *regs)
191 {
192         if (!test_tsk_trace_trace(current))
193                 return;
194 
195         ftrace_pid_function(ip, parent_ip, op, regs);
196 }
197 
198 static void set_ftrace_pid_function(ftrace_func_t func)
199 {
200         /* do not set ftrace_pid_function to itself! */
201         if (func != ftrace_pid_func)
202                 ftrace_pid_function = func;
203 }
204 
205 /**
206  * clear_ftrace_function - reset the ftrace function
207  *
208  * This NULLs the ftrace function and in essence stops
209  * tracing.  There may be lag
210  */
211 void clear_ftrace_function(void)
212 {
213         ftrace_trace_function = ftrace_stub;
214         ftrace_pid_function = ftrace_stub;
215 }
216 
217 static void control_ops_disable_all(struct ftrace_ops *ops)
218 {
219         int cpu;
220 
221         for_each_possible_cpu(cpu)
222                 *per_cpu_ptr(ops->disabled, cpu) = 1;
223 }
224 
225 static int control_ops_alloc(struct ftrace_ops *ops)
226 {
227         int __percpu *disabled;
228 
229         disabled = alloc_percpu(int);
230         if (!disabled)
231                 return -ENOMEM;
232 
233         ops->disabled = disabled;
234         control_ops_disable_all(ops);
235         return 0;
236 }
237 
238 static void control_ops_free(struct ftrace_ops *ops)
239 {
240         free_percpu(ops->disabled);
241 }
242 
243 static void update_global_ops(void)
244 {
245         ftrace_func_t func;
246 
247         /*
248          * If there's only one function registered, then call that
249          * function directly. Otherwise, we need to iterate over the
250          * registered callers.
251          */
252         if (ftrace_global_list == &ftrace_list_end ||
253             ftrace_global_list->next == &ftrace_list_end) {
254                 func = ftrace_global_list->func;
255                 /*
256                  * As we are calling the function directly.
257                  * If it does not have recursion protection,
258                  * the function_trace_op needs to be updated
259                  * accordingly.
260                  */
261                 if (ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE)
262                         global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
263                 else
264                         global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
265         } else {
266                 func = ftrace_global_list_func;
267                 /* The list has its own recursion protection. */
268                 global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
269         }
270 
271 
272         /* If we filter on pids, update to use the pid function */
273         if (!list_empty(&ftrace_pids)) {
274                 set_ftrace_pid_function(func);
275                 func = ftrace_pid_func;
276         }
277 
278         global_ops.func = func;
279 }
280 
281 static void update_ftrace_function(void)
282 {
283         ftrace_func_t func;
284 
285         update_global_ops();
286 
287         /*
288          * If we are at the end of the list and this ops is
289          * recursion safe and not dynamic and the arch supports passing ops,
290          * then have the mcount trampoline call the function directly.
291          */
292         if (ftrace_ops_list == &ftrace_list_end ||
293             (ftrace_ops_list->next == &ftrace_list_end &&
294              !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC) &&
295              (ftrace_ops_list->flags & FTRACE_OPS_FL_RECURSION_SAFE) &&
296              !FTRACE_FORCE_LIST_FUNC)) {
297                 /* Set the ftrace_ops that the arch callback uses */
298                 if (ftrace_ops_list == &global_ops)
299                         function_trace_op = ftrace_global_list;
300                 else
301                         function_trace_op = ftrace_ops_list;
302                 func = ftrace_ops_list->func;
303         } else {
304                 /* Just use the default ftrace_ops */
305                 function_trace_op = &ftrace_list_end;
306                 func = ftrace_ops_list_func;
307         }
308 
309         ftrace_trace_function = func;
310 }
311 
312 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
313 {
314         ops->next = *list;
315         /*
316          * We are entering ops into the list but another
317          * CPU might be walking that list. We need to make sure
318          * the ops->next pointer is valid before another CPU sees
319          * the ops pointer included into the list.
320          */
321         rcu_assign_pointer(*list, ops);
322 }
323 
324 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
325 {
326         struct ftrace_ops **p;
327 
328         /*
329          * If we are removing the last function, then simply point
330          * to the ftrace_stub.
331          */
332         if (*list == ops && ops->next == &ftrace_list_end) {
333                 *list = &ftrace_list_end;
334                 return 0;
335         }
336 
337         for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
338                 if (*p == ops)
339                         break;
340 
341         if (*p != ops)
342                 return -1;
343 
344         *p = (*p)->next;
345         return 0;
346 }
347 
348 static void add_ftrace_list_ops(struct ftrace_ops **list,
349                                 struct ftrace_ops *main_ops,
350                                 struct ftrace_ops *ops)
351 {
352         int first = *list == &ftrace_list_end;
353         add_ftrace_ops(list, ops);
354         if (first)
355                 add_ftrace_ops(&ftrace_ops_list, main_ops);
356 }
357 
358 static int remove_ftrace_list_ops(struct ftrace_ops **list,
359                                   struct ftrace_ops *main_ops,
360                                   struct ftrace_ops *ops)
361 {
362         int ret = remove_ftrace_ops(list, ops);
363         if (!ret && *list == &ftrace_list_end)
364                 ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
365         return ret;
366 }
367 
368 static int __register_ftrace_function(struct ftrace_ops *ops)
369 {
370         if (unlikely(ftrace_disabled))
371                 return -ENODEV;
372 
373         if (FTRACE_WARN_ON(ops == &global_ops))
374                 return -EINVAL;
375 
376         if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
377                 return -EBUSY;
378 
379         /* We don't support both control and global flags set. */
380         if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
381                 return -EINVAL;
382 
383 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
384         /*
385          * If the ftrace_ops specifies SAVE_REGS, then it only can be used
386          * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
387          * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
388          */
389         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
390             !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
391                 return -EINVAL;
392 
393         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
394                 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
395 #endif
396 
397         if (!core_kernel_data((unsigned long)ops))
398                 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
399 
400         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
401                 add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
402                 ops->flags |= FTRACE_OPS_FL_ENABLED;
403         } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
404                 if (control_ops_alloc(ops))
405                         return -ENOMEM;
406                 add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
407         } else
408                 add_ftrace_ops(&ftrace_ops_list, ops);
409 
410         if (ftrace_enabled)
411                 update_ftrace_function();
412 
413         return 0;
414 }
415 
416 static void ftrace_sync(struct work_struct *work)
417 {
418         /*
419          * This function is just a stub to implement a hard force
420          * of synchronize_sched(). This requires synchronizing
421          * tasks even in userspace and idle.
422          *
423          * Yes, function tracing is rude.
424          */
425 }
426 
427 static int __unregister_ftrace_function(struct ftrace_ops *ops)
428 {
429         int ret;
430 
431         if (ftrace_disabled)
432                 return -ENODEV;
433 
434         if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
435                 return -EBUSY;
436 
437         if (FTRACE_WARN_ON(ops == &global_ops))
438                 return -EINVAL;
439 
440         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
441                 ret = remove_ftrace_list_ops(&ftrace_global_list,
442                                              &global_ops, ops);
443                 if (!ret)
444                         ops->flags &= ~FTRACE_OPS_FL_ENABLED;
445         } else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
446                 ret = remove_ftrace_list_ops(&ftrace_control_list,
447                                              &control_ops, ops);
448                 if (!ret) {
449                         /*
450                          * The ftrace_ops is now removed from the list,
451                          * so there'll be no new users. We must ensure
452                          * all current users are done before we free
453                          * the control data.
454                          * Note synchronize_sched() is not enough, as we
455                          * use preempt_disable() to do RCU, but the function
456                          * tracer can be called where RCU is not active
457                          * (before user_exit()).
458                          */
459                         schedule_on_each_cpu(ftrace_sync);
460                         control_ops_free(ops);
461                 }
462         } else
463                 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
464 
465         if (ret < 0)
466                 return ret;
467 
468         if (ftrace_enabled)
469                 update_ftrace_function();
470 
471         /*
472          * Dynamic ops may be freed, we must make sure that all
473          * callers are done before leaving this function.
474          *
475          * Again, normal synchronize_sched() is not good enough.
476          * We need to do a hard force of sched synchronization.
477          */
478         if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
479                 schedule_on_each_cpu(ftrace_sync);
480 
481 
482         return 0;
483 }
484 
485 static void ftrace_update_pid_func(void)
486 {
487         /* Only do something if we are tracing something */
488         if (ftrace_trace_function == ftrace_stub)
489                 return;
490 
491         update_ftrace_function();
492 }
493 
494 #ifdef CONFIG_FUNCTION_PROFILER
495 struct ftrace_profile {
496         struct hlist_node               node;
497         unsigned long                   ip;
498         unsigned long                   counter;
499 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
500         unsigned long long              time;
501         unsigned long long              time_squared;
502 #endif
503 };
504 
505 struct ftrace_profile_page {
506         struct ftrace_profile_page      *next;
507         unsigned long                   index;
508         struct ftrace_profile           records[];
509 };
510 
511 struct ftrace_profile_stat {
512         atomic_t                        disabled;
513         struct hlist_head               *hash;
514         struct ftrace_profile_page      *pages;
515         struct ftrace_profile_page      *start;
516         struct tracer_stat              stat;
517 };
518 
519 #define PROFILE_RECORDS_SIZE                                            \
520         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
521 
522 #define PROFILES_PER_PAGE                                       \
523         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
524 
525 static int ftrace_profile_enabled __read_mostly;
526 
527 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
528 static DEFINE_MUTEX(ftrace_profile_lock);
529 
530 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
531 
532 #define FTRACE_PROFILE_HASH_BITS 10
533 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
534 
535 static void *
536 function_stat_next(void *v, int idx)
537 {
538         struct ftrace_profile *rec = v;
539         struct ftrace_profile_page *pg;
540 
541         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
542 
543  again:
544         if (idx != 0)
545                 rec++;
546 
547         if ((void *)rec >= (void *)&pg->records[pg->index]) {
548                 pg = pg->next;
549                 if (!pg)
550                         return NULL;
551                 rec = &pg->records[0];
552                 if (!rec->counter)
553                         goto again;
554         }
555 
556         return rec;
557 }
558 
559 static void *function_stat_start(struct tracer_stat *trace)
560 {
561         struct ftrace_profile_stat *stat =
562                 container_of(trace, struct ftrace_profile_stat, stat);
563 
564         if (!stat || !stat->start)
565                 return NULL;
566 
567         return function_stat_next(&stat->start->records[0], 0);
568 }
569 
570 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
571 /* function graph compares on total time */
572 static int function_stat_cmp(void *p1, void *p2)
573 {
574         struct ftrace_profile *a = p1;
575         struct ftrace_profile *b = p2;
576 
577         if (a->time < b->time)
578                 return -1;
579         if (a->time > b->time)
580                 return 1;
581         else
582                 return 0;
583 }
584 #else
585 /* not function graph compares against hits */
586 static int function_stat_cmp(void *p1, void *p2)
587 {
588         struct ftrace_profile *a = p1;
589         struct ftrace_profile *b = p2;
590 
591         if (a->counter < b->counter)
592                 return -1;
593         if (a->counter > b->counter)
594                 return 1;
595         else
596                 return 0;
597 }
598 #endif
599 
600 static int function_stat_headers(struct seq_file *m)
601 {
602 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
603         seq_printf(m, "  Function                               "
604                    "Hit    Time            Avg             s^2\n"
605                       "  --------                               "
606                    "---    ----            ---             ---\n");
607 #else
608         seq_printf(m, "  Function                               Hit\n"
609                       "  --------                               ---\n");
610 #endif
611         return 0;
612 }
613 
614 static int function_stat_show(struct seq_file *m, void *v)
615 {
616         struct ftrace_profile *rec = v;
617         char str[KSYM_SYMBOL_LEN];
618         int ret = 0;
619 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
620         static struct trace_seq s;
621         unsigned long long avg;
622         unsigned long long stddev;
623 #endif
624         mutex_lock(&ftrace_profile_lock);
625 
626         /* we raced with function_profile_reset() */
627         if (unlikely(rec->counter == 0)) {
628                 ret = -EBUSY;
629                 goto out;
630         }
631 
632         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
633         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
634 
635 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
636         seq_printf(m, "    ");
637         avg = rec->time;
638         do_div(avg, rec->counter);
639 
640         /* Sample standard deviation (s^2) */
641         if (rec->counter <= 1)
642                 stddev = 0;
643         else {
644                 /*
645                  * Apply Welford's method:
646                  * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
647                  */
648                 stddev = rec->counter * rec->time_squared -
649                          rec->time * rec->time;
650 
651                 /*
652                  * Divide only 1000 for ns^2 -> us^2 conversion.
653                  * trace_print_graph_duration will divide 1000 again.
654                  */
655                 do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
656         }
657 
658         trace_seq_init(&s);
659         trace_print_graph_duration(rec->time, &s);
660         trace_seq_puts(&s, "    ");
661         trace_print_graph_duration(avg, &s);
662         trace_seq_puts(&s, "    ");
663         trace_print_graph_duration(stddev, &s);
664         trace_print_seq(m, &s);
665 #endif
666         seq_putc(m, '\n');
667 out:
668         mutex_unlock(&ftrace_profile_lock);
669 
670         return ret;
671 }
672 
673 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
674 {
675         struct ftrace_profile_page *pg;
676 
677         pg = stat->pages = stat->start;
678 
679         while (pg) {
680                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
681                 pg->index = 0;
682                 pg = pg->next;
683         }
684 
685         memset(stat->hash, 0,
686                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
687 }
688 
689 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
690 {
691         struct ftrace_profile_page *pg;
692         int functions;
693         int pages;
694         int i;
695 
696         /* If we already allocated, do nothing */
697         if (stat->pages)
698                 return 0;
699 
700         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
701         if (!stat->pages)
702                 return -ENOMEM;
703 
704 #ifdef CONFIG_DYNAMIC_FTRACE
705         functions = ftrace_update_tot_cnt;
706 #else
707         /*
708          * We do not know the number of functions that exist because
709          * dynamic tracing is what counts them. With past experience
710          * we have around 20K functions. That should be more than enough.
711          * It is highly unlikely we will execute every function in
712          * the kernel.
713          */
714         functions = 20000;
715 #endif
716 
717         pg = stat->start = stat->pages;
718 
719         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
720 
721         for (i = 1; i < pages; i++) {
722                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
723                 if (!pg->next)
724                         goto out_free;
725                 pg = pg->next;
726         }
727 
728         return 0;
729 
730  out_free:
731         pg = stat->start;
732         while (pg) {
733                 unsigned long tmp = (unsigned long)pg;
734 
735                 pg = pg->next;
736                 free_page(tmp);
737         }
738 
739         stat->pages = NULL;
740         stat->start = NULL;
741 
742         return -ENOMEM;
743 }
744 
745 static int ftrace_profile_init_cpu(int cpu)
746 {
747         struct ftrace_profile_stat *stat;
748         int size;
749 
750         stat = &per_cpu(ftrace_profile_stats, cpu);
751 
752         if (stat->hash) {
753                 /* If the profile is already created, simply reset it */
754                 ftrace_profile_reset(stat);
755                 return 0;
756         }
757 
758         /*
759          * We are profiling all functions, but usually only a few thousand
760          * functions are hit. We'll make a hash of 1024 items.
761          */
762         size = FTRACE_PROFILE_HASH_SIZE;
763 
764         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
765 
766         if (!stat->hash)
767                 return -ENOMEM;
768 
769         /* Preallocate the function profiling pages */
770         if (ftrace_profile_pages_init(stat) < 0) {
771                 kfree(stat->hash);
772                 stat->hash = NULL;
773                 return -ENOMEM;
774         }
775 
776         return 0;
777 }
778 
779 static int ftrace_profile_init(void)
780 {
781         int cpu;
782         int ret = 0;
783 
784         for_each_online_cpu(cpu) {
785                 ret = ftrace_profile_init_cpu(cpu);
786                 if (ret)
787                         break;
788         }
789 
790         return ret;
791 }
792 
793 /* interrupts must be disabled */
794 static struct ftrace_profile *
795 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
796 {
797         struct ftrace_profile *rec;
798         struct hlist_head *hhd;
799         unsigned long key;
800 
801         key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
802         hhd = &stat->hash[key];
803 
804         if (hlist_empty(hhd))
805                 return NULL;
806 
807         hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
808                 if (rec->ip == ip)
809                         return rec;
810         }
811 
812         return NULL;
813 }
814 
815 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
816                                struct ftrace_profile *rec)
817 {
818         unsigned long key;
819 
820         key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
821         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
822 }
823 
824 /*
825  * The memory is already allocated, this simply finds a new record to use.
826  */
827 static struct ftrace_profile *
828 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
829 {
830         struct ftrace_profile *rec = NULL;
831 
832         /* prevent recursion (from NMIs) */
833         if (atomic_inc_return(&stat->disabled) != 1)
834                 goto out;
835 
836         /*
837          * Try to find the function again since an NMI
838          * could have added it
839          */
840         rec = ftrace_find_profiled_func(stat, ip);
841         if (rec)
842                 goto out;
843 
844         if (stat->pages->index == PROFILES_PER_PAGE) {
845                 if (!stat->pages->next)
846                         goto out;
847                 stat->pages = stat->pages->next;
848         }
849 
850         rec = &stat->pages->records[stat->pages->index++];
851         rec->ip = ip;
852         ftrace_add_profile(stat, rec);
853 
854  out:
855         atomic_dec(&stat->disabled);
856 
857         return rec;
858 }
859 
860 static void
861 function_profile_call(unsigned long ip, unsigned long parent_ip,
862                       struct ftrace_ops *ops, struct pt_regs *regs)
863 {
864         struct ftrace_profile_stat *stat;
865         struct ftrace_profile *rec;
866         unsigned long flags;
867 
868         if (!ftrace_profile_enabled)
869                 return;
870 
871         local_irq_save(flags);
872 
873         stat = &__get_cpu_var(ftrace_profile_stats);
874         if (!stat->hash || !ftrace_profile_enabled)
875                 goto out;
876 
877         rec = ftrace_find_profiled_func(stat, ip);
878         if (!rec) {
879                 rec = ftrace_profile_alloc(stat, ip);
880                 if (!rec)
881                         goto out;
882         }
883 
884         rec->counter++;
885  out:
886         local_irq_restore(flags);
887 }
888 
889 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
890 static int profile_graph_entry(struct ftrace_graph_ent *trace)
891 {
892         function_profile_call(trace->func, 0, NULL, NULL);
893         return 1;
894 }
895 
896 static void profile_graph_return(struct ftrace_graph_ret *trace)
897 {
898         struct ftrace_profile_stat *stat;
899         unsigned long long calltime;
900         struct ftrace_profile *rec;
901         unsigned long flags;
902 
903         local_irq_save(flags);
904         stat = &__get_cpu_var(ftrace_profile_stats);
905         if (!stat->hash || !ftrace_profile_enabled)
906                 goto out;
907 
908         /* If the calltime was zero'd ignore it */
909         if (!trace->calltime)
910                 goto out;
911 
912         calltime = trace->rettime - trace->calltime;
913 
914         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
915                 int index;
916 
917                 index = trace->depth;
918 
919                 /* Append this call time to the parent time to subtract */
920                 if (index)
921                         current->ret_stack[index - 1].subtime += calltime;
922 
923                 if (current->ret_stack[index].subtime < calltime)
924                         calltime -= current->ret_stack[index].subtime;
925                 else
926                         calltime = 0;
927         }
928 
929         rec = ftrace_find_profiled_func(stat, trace->func);
930         if (rec) {
931                 rec->time += calltime;
932                 rec->time_squared += calltime * calltime;
933         }
934 
935  out:
936         local_irq_restore(flags);
937 }
938 
939 static int register_ftrace_profiler(void)
940 {
941         return register_ftrace_graph(&profile_graph_return,
942                                      &profile_graph_entry);
943 }
944 
945 static void unregister_ftrace_profiler(void)
946 {
947         unregister_ftrace_graph();
948 }
949 #else
950 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
951         .func           = function_profile_call,
952         .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
953         INIT_REGEX_LOCK(ftrace_profile_ops)
954 };
955 
956 static int register_ftrace_profiler(void)
957 {
958         return register_ftrace_function(&ftrace_profile_ops);
959 }
960 
961 static void unregister_ftrace_profiler(void)
962 {
963         unregister_ftrace_function(&ftrace_profile_ops);
964 }
965 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
966 
967 static ssize_t
968 ftrace_profile_write(struct file *filp, const char __user *ubuf,
969                      size_t cnt, loff_t *ppos)
970 {
971         unsigned long val;
972         int ret;
973 
974         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
975         if (ret)
976                 return ret;
977 
978         val = !!val;
979 
980         mutex_lock(&ftrace_profile_lock);
981         if (ftrace_profile_enabled ^ val) {
982                 if (val) {
983                         ret = ftrace_profile_init();
984                         if (ret < 0) {
985                                 cnt = ret;
986                                 goto out;
987                         }
988 
989                         ret = register_ftrace_profiler();
990                         if (ret < 0) {
991                                 cnt = ret;
992                                 goto out;
993                         }
994                         ftrace_profile_enabled = 1;
995                 } else {
996                         ftrace_profile_enabled = 0;
997                         /*
998                          * unregister_ftrace_profiler calls stop_machine
999                          * so this acts like an synchronize_sched.
1000                          */
1001                         unregister_ftrace_profiler();
1002                 }
1003         }
1004  out:
1005         mutex_unlock(&ftrace_profile_lock);
1006 
1007         *ppos += cnt;
1008 
1009         return cnt;
1010 }
1011 
1012 static ssize_t
1013 ftrace_profile_read(struct file *filp, char __user *ubuf,
1014                      size_t cnt, loff_t *ppos)
1015 {
1016         char buf[64];           /* big enough to hold a number */
1017         int r;
1018 
1019         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
1020         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1021 }
1022 
1023 static const struct file_operations ftrace_profile_fops = {
1024         .open           = tracing_open_generic,
1025         .read           = ftrace_profile_read,
1026         .write          = ftrace_profile_write,
1027         .llseek         = default_llseek,
1028 };
1029 
1030 /* used to initialize the real stat files */
1031 static struct tracer_stat function_stats __initdata = {
1032         .name           = "functions",
1033         .stat_start     = function_stat_start,
1034         .stat_next      = function_stat_next,
1035         .stat_cmp       = function_stat_cmp,
1036         .stat_headers   = function_stat_headers,
1037         .stat_show      = function_stat_show
1038 };
1039 
1040 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1041 {
1042         struct ftrace_profile_stat *stat;
1043         struct dentry *entry;
1044         char *name;
1045         int ret;
1046         int cpu;
1047 
1048         for_each_possible_cpu(cpu) {
1049                 stat = &per_cpu(ftrace_profile_stats, cpu);
1050 
1051                 /* allocate enough for function name + cpu number */
1052                 name = kmalloc(32, GFP_KERNEL);
1053                 if (!name) {
1054                         /*
1055                          * The files created are permanent, if something happens
1056                          * we still do not free memory.
1057                          */
1058                         WARN(1,
1059                              "Could not allocate stat file for cpu %d\n",
1060                              cpu);
1061                         return;
1062                 }
1063                 stat->stat = function_stats;
1064                 snprintf(name, 32, "function%d", cpu);
1065                 stat->stat.name = name;
1066                 ret = register_stat_tracer(&stat->stat);
1067                 if (ret) {
1068                         WARN(1,
1069                              "Could not register function stat for cpu %d\n",
1070                              cpu);
1071                         kfree(name);
1072                         return;
1073                 }
1074         }
1075 
1076         entry = debugfs_create_file("function_profile_enabled", 0644,
1077                                     d_tracer, NULL, &ftrace_profile_fops);
1078         if (!entry)
1079                 pr_warning("Could not create debugfs "
1080                            "'function_profile_enabled' entry\n");
1081 }
1082 
1083 #else /* CONFIG_FUNCTION_PROFILER */
1084 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1085 {
1086 }
1087 #endif /* CONFIG_FUNCTION_PROFILER */
1088 
1089 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1090 
1091 loff_t
1092 ftrace_filter_lseek(struct file *file, loff_t offset, int whence)
1093 {
1094         loff_t ret;
1095 
1096         if (file->f_mode & FMODE_READ)
1097                 ret = seq_lseek(file, offset, whence);
1098         else
1099                 file->f_pos = ret = 1;
1100 
1101         return ret;
1102 }
1103 
1104 #ifdef CONFIG_DYNAMIC_FTRACE
1105 
1106 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1107 # error Dynamic ftrace depends on MCOUNT_RECORD
1108 #endif
1109 
1110 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1111 
1112 struct ftrace_func_probe {
1113         struct hlist_node       node;
1114         struct ftrace_probe_ops *ops;
1115         unsigned long           flags;
1116         unsigned long           ip;
1117         void                    *data;
1118         struct list_head        free_list;
1119 };
1120 
1121 struct ftrace_func_entry {
1122         struct hlist_node hlist;
1123         unsigned long ip;
1124 };
1125 
1126 struct ftrace_hash {
1127         unsigned long           size_bits;
1128         struct hlist_head       *buckets;
1129         unsigned long           count;
1130         struct rcu_head         rcu;
1131 };
1132 
1133 /*
1134  * We make these constant because no one should touch them,
1135  * but they are used as the default "empty hash", to avoid allocating
1136  * it all the time. These are in a read only section such that if
1137  * anyone does try to modify it, it will cause an exception.
1138  */
1139 static const struct hlist_head empty_buckets[1];
1140 static const struct ftrace_hash empty_hash = {
1141         .buckets = (struct hlist_head *)empty_buckets,
1142 };
1143 #define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
1144 
1145 static struct ftrace_ops global_ops = {
1146         .func                   = ftrace_stub,
1147         .notrace_hash           = EMPTY_HASH,
1148         .filter_hash            = EMPTY_HASH,
1149         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
1150         INIT_REGEX_LOCK(global_ops)
1151 };
1152 
1153 struct ftrace_page {
1154         struct ftrace_page      *next;
1155         struct dyn_ftrace       *records;
1156         int                     index;
1157         int                     size;
1158 };
1159 
1160 static struct ftrace_page *ftrace_new_pgs;
1161 
1162 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1163 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1164 
1165 /* estimate from running different kernels */
1166 #define NR_TO_INIT              10000
1167 
1168 static struct ftrace_page       *ftrace_pages_start;
1169 static struct ftrace_page       *ftrace_pages;
1170 
1171 static bool ftrace_hash_empty(struct ftrace_hash *hash)
1172 {
1173         return !hash || !hash->count;
1174 }
1175 
1176 static struct ftrace_func_entry *
1177 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1178 {
1179         unsigned long key;
1180         struct ftrace_func_entry *entry;
1181         struct hlist_head *hhd;
1182 
1183         if (ftrace_hash_empty(hash))
1184                 return NULL;
1185 
1186         if (hash->size_bits > 0)
1187                 key = hash_long(ip, hash->size_bits);
1188         else
1189                 key = 0;
1190 
1191         hhd = &hash->buckets[key];
1192 
1193         hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1194                 if (entry->ip == ip)
1195                         return entry;
1196         }
1197         return NULL;
1198 }
1199 
1200 static void __add_hash_entry(struct ftrace_hash *hash,
1201                              struct ftrace_func_entry *entry)
1202 {
1203         struct hlist_head *hhd;
1204         unsigned long key;
1205 
1206         if (hash->size_bits)
1207                 key = hash_long(entry->ip, hash->size_bits);
1208         else
1209                 key = 0;
1210 
1211         hhd = &hash->buckets[key];
1212         hlist_add_head(&entry->hlist, hhd);
1213         hash->count++;
1214 }
1215 
1216 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1217 {
1218         struct ftrace_func_entry *entry;
1219 
1220         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1221         if (!entry)
1222                 return -ENOMEM;
1223 
1224         entry->ip = ip;
1225         __add_hash_entry(hash, entry);
1226 
1227         return 0;
1228 }
1229 
1230 static void
1231 free_hash_entry(struct ftrace_hash *hash,
1232                   struct ftrace_func_entry *entry)
1233 {
1234         hlist_del(&entry->hlist);
1235         kfree(entry);
1236         hash->count--;
1237 }
1238 
1239 static void
1240 remove_hash_entry(struct ftrace_hash *hash,
1241                   struct ftrace_func_entry *entry)
1242 {
1243         hlist_del(&entry->hlist);
1244         hash->count--;
1245 }
1246 
1247 static void ftrace_hash_clear(struct ftrace_hash *hash)
1248 {
1249         struct hlist_head *hhd;
1250         struct hlist_node *tn;
1251         struct ftrace_func_entry *entry;
1252         int size = 1 << hash->size_bits;
1253         int i;
1254 
1255         if (!hash->count)
1256                 return;
1257 
1258         for (i = 0; i < size; i++) {
1259                 hhd = &hash->buckets[i];
1260                 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1261                         free_hash_entry(hash, entry);
1262         }
1263         FTRACE_WARN_ON(hash->count);
1264 }
1265 
1266 static void free_ftrace_hash(struct ftrace_hash *hash)
1267 {
1268         if (!hash || hash == EMPTY_HASH)
1269                 return;
1270         ftrace_hash_clear(hash);
1271         kfree(hash->buckets);
1272         kfree(hash);
1273 }
1274 
1275 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1276 {
1277         struct ftrace_hash *hash;
1278 
1279         hash = container_of(rcu, struct ftrace_hash, rcu);
1280         free_ftrace_hash(hash);
1281 }
1282 
1283 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1284 {
1285         if (!hash || hash == EMPTY_HASH)
1286                 return;
1287         call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1288 }
1289 
1290 void ftrace_free_filter(struct ftrace_ops *ops)
1291 {
1292         ftrace_ops_init(ops);
1293         free_ftrace_hash(ops->filter_hash);
1294         free_ftrace_hash(ops->notrace_hash);
1295 }
1296 
1297 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1298 {
1299         struct ftrace_hash *hash;
1300         int size;
1301 
1302         hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1303         if (!hash)
1304                 return NULL;
1305 
1306         size = 1 << size_bits;
1307         hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1308 
1309         if (!hash->buckets) {
1310                 kfree(hash);
1311                 return NULL;
1312         }
1313 
1314         hash->size_bits = size_bits;
1315 
1316         return hash;
1317 }
1318 
1319 static struct ftrace_hash *
1320 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1321 {
1322         struct ftrace_func_entry *entry;
1323         struct ftrace_hash *new_hash;
1324         int size;
1325         int ret;
1326         int i;
1327 
1328         new_hash = alloc_ftrace_hash(size_bits);
1329         if (!new_hash)
1330                 return NULL;
1331 
1332         /* Empty hash? */
1333         if (ftrace_hash_empty(hash))
1334                 return new_hash;
1335 
1336         size = 1 << hash->size_bits;
1337         for (i = 0; i < size; i++) {
1338                 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1339                         ret = add_hash_entry(new_hash, entry->ip);
1340                         if (ret < 0)
1341                                 goto free_hash;
1342                 }
1343         }
1344 
1345         FTRACE_WARN_ON(new_hash->count != hash->count);
1346 
1347         return new_hash;
1348 
1349  free_hash:
1350         free_ftrace_hash(new_hash);
1351         return NULL;
1352 }
1353 
1354 static void
1355 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1356 static void
1357 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1358 
1359 static int
1360 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1361                  struct ftrace_hash **dst, struct ftrace_hash *src)
1362 {
1363         struct ftrace_func_entry *entry;
1364         struct hlist_node *tn;
1365         struct hlist_head *hhd;
1366         struct ftrace_hash *old_hash;
1367         struct ftrace_hash *new_hash;
1368         int size = src->count;
1369         int bits = 0;
1370         int ret;
1371         int i;
1372 
1373         /*
1374          * Remove the current set, update the hash and add
1375          * them back.
1376          */
1377         ftrace_hash_rec_disable(ops, enable);
1378 
1379         /*
1380          * If the new source is empty, just free dst and assign it
1381          * the empty_hash.
1382          */
1383         if (!src->count) {
1384                 free_ftrace_hash_rcu(*dst);
1385                 rcu_assign_pointer(*dst, EMPTY_HASH);
1386                 /* still need to update the function records */
1387                 ret = 0;
1388                 goto out;
1389         }
1390 
1391         /*
1392          * Make the hash size about 1/2 the # found
1393          */
1394         for (size /= 2; size; size >>= 1)
1395                 bits++;
1396 
1397         /* Don't allocate too much */
1398         if (bits > FTRACE_HASH_MAX_BITS)
1399                 bits = FTRACE_HASH_MAX_BITS;
1400 
1401         ret = -ENOMEM;
1402         new_hash = alloc_ftrace_hash(bits);
1403         if (!new_hash)
1404                 goto out;
1405 
1406         size = 1 << src->size_bits;
1407         for (i = 0; i < size; i++) {
1408                 hhd = &src->buckets[i];
1409                 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1410                         remove_hash_entry(src, entry);
1411                         __add_hash_entry(new_hash, entry);
1412                 }
1413         }
1414 
1415         old_hash = *dst;
1416         rcu_assign_pointer(*dst, new_hash);
1417         free_ftrace_hash_rcu(old_hash);
1418 
1419         ret = 0;
1420  out:
1421         /*
1422          * Enable regardless of ret:
1423          *  On success, we enable the new hash.
1424          *  On failure, we re-enable the original hash.
1425          */
1426         ftrace_hash_rec_enable(ops, enable);
1427 
1428         return ret;
1429 }
1430 
1431 /*
1432  * Test the hashes for this ops to see if we want to call
1433  * the ops->func or not.
1434  *
1435  * It's a match if the ip is in the ops->filter_hash or
1436  * the filter_hash does not exist or is empty,
1437  *  AND
1438  * the ip is not in the ops->notrace_hash.
1439  *
1440  * This needs to be called with preemption disabled as
1441  * the hashes are freed with call_rcu_sched().
1442  */
1443 static int
1444 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1445 {
1446         struct ftrace_hash *filter_hash;
1447         struct ftrace_hash *notrace_hash;
1448         int ret;
1449 
1450 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1451         /*
1452          * There's a small race when adding ops that the ftrace handler
1453          * that wants regs, may be called without them. We can not
1454          * allow that handler to be called if regs is NULL.
1455          */
1456         if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1457                 return 0;
1458 #endif
1459 
1460         filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
1461         notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
1462 
1463         if ((ftrace_hash_empty(filter_hash) ||
1464              ftrace_lookup_ip(filter_hash, ip)) &&
1465             (ftrace_hash_empty(notrace_hash) ||
1466              !ftrace_lookup_ip(notrace_hash, ip)))
1467                 ret = 1;
1468         else
1469                 ret = 0;
1470 
1471         return ret;
1472 }
1473 
1474 /*
1475  * This is a double for. Do not use 'break' to break out of the loop,
1476  * you must use a goto.
1477  */
1478 #define do_for_each_ftrace_rec(pg, rec)                                 \
1479         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
1480                 int _____i;                                             \
1481                 for (_____i = 0; _____i < pg->index; _____i++) {        \
1482                         rec = &pg->records[_____i];
1483 
1484 #define while_for_each_ftrace_rec()             \
1485                 }                               \
1486         }
1487 
1488 
1489 static int ftrace_cmp_recs(const void *a, const void *b)
1490 {
1491         const struct dyn_ftrace *key = a;
1492         const struct dyn_ftrace *rec = b;
1493 
1494         if (key->flags < rec->ip)
1495                 return -1;
1496         if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1497                 return 1;
1498         return 0;
1499 }
1500 
1501 static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1502 {
1503         struct ftrace_page *pg;
1504         struct dyn_ftrace *rec;
1505         struct dyn_ftrace key;
1506 
1507         key.ip = start;
1508         key.flags = end;        /* overload flags, as it is unsigned long */
1509 
1510         for (pg = ftrace_pages_start; pg; pg = pg->next) {
1511                 if (end < pg->records[0].ip ||
1512                     start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1513                         continue;
1514                 rec = bsearch(&key, pg->records, pg->index,
1515                               sizeof(struct dyn_ftrace),
1516                               ftrace_cmp_recs);
1517                 if (rec)
1518                         return rec->ip;
1519         }
1520 
1521         return 0;
1522 }
1523 
1524 /**
1525  * ftrace_location - return true if the ip giving is a traced location
1526  * @ip: the instruction pointer to check
1527  *
1528  * Returns rec->ip if @ip given is a pointer to a ftrace location.
1529  * That is, the instruction that is either a NOP or call to
1530  * the function tracer. It checks the ftrace internal tables to
1531  * determine if the address belongs or not.
1532  */
1533 unsigned long ftrace_location(unsigned long ip)
1534 {
1535         return ftrace_location_range(ip, ip);
1536 }
1537 
1538 /**
1539  * ftrace_text_reserved - return true if range contains an ftrace location
1540  * @start: start of range to search
1541  * @end: end of range to search (inclusive). @end points to the last byte to check.
1542  *
1543  * Returns 1 if @start and @end contains a ftrace location.
1544  * That is, the instruction that is either a NOP or call to
1545  * the function tracer. It checks the ftrace internal tables to
1546  * determine if the address belongs or not.
1547  */
1548 int ftrace_text_reserved(void *start, void *end)
1549 {
1550         unsigned long ret;
1551 
1552         ret = ftrace_location_range((unsigned long)start,
1553                                     (unsigned long)end);
1554 
1555         return (int)!!ret;
1556 }
1557 
1558 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1559                                      int filter_hash,
1560                                      bool inc)
1561 {
1562         struct ftrace_hash *hash;
1563         struct ftrace_hash *other_hash;
1564         struct ftrace_page *pg;
1565         struct dyn_ftrace *rec;
1566         int count = 0;
1567         int all = 0;
1568 
1569         /* Only update if the ops has been registered */
1570         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1571                 return;
1572 
1573         /*
1574          * In the filter_hash case:
1575          *   If the count is zero, we update all records.
1576          *   Otherwise we just update the items in the hash.
1577          *
1578          * In the notrace_hash case:
1579          *   We enable the update in the hash.
1580          *   As disabling notrace means enabling the tracing,
1581          *   and enabling notrace means disabling, the inc variable
1582          *   gets inversed.
1583          */
1584         if (filter_hash) {
1585                 hash = ops->filter_hash;
1586                 other_hash = ops->notrace_hash;
1587                 if (ftrace_hash_empty(hash))
1588                         all = 1;
1589         } else {
1590                 inc = !inc;
1591                 hash = ops->notrace_hash;
1592                 other_hash = ops->filter_hash;
1593                 /*
1594                  * If the notrace hash has no items,
1595                  * then there's nothing to do.
1596                  */
1597                 if (ftrace_hash_empty(hash))
1598                         return;
1599         }
1600 
1601         do_for_each_ftrace_rec(pg, rec) {
1602                 int in_other_hash = 0;
1603                 int in_hash = 0;
1604                 int match = 0;
1605 
1606                 if (all) {
1607                         /*
1608                          * Only the filter_hash affects all records.
1609                          * Update if the record is not in the notrace hash.
1610                          */
1611                         if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1612                                 match = 1;
1613                 } else {
1614                         in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1615                         in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1616 
1617                         /*
1618                          *
1619                          */
1620                         if (filter_hash && in_hash && !in_other_hash)
1621                                 match = 1;
1622                         else if (!filter_hash && in_hash &&
1623                                  (in_other_hash || ftrace_hash_empty(other_hash)))
1624                                 match = 1;
1625                 }
1626                 if (!match)
1627                         continue;
1628 
1629                 if (inc) {
1630                         rec->flags++;
1631                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1632                                 return;
1633                         /*
1634                          * If any ops wants regs saved for this function
1635                          * then all ops will get saved regs.
1636                          */
1637                         if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1638                                 rec->flags |= FTRACE_FL_REGS;
1639                 } else {
1640                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1641                                 return;
1642                         rec->flags--;
1643                 }
1644                 count++;
1645                 /* Shortcut, if we handled all records, we are done. */
1646                 if (!all && count == hash->count)
1647                         return;
1648         } while_for_each_ftrace_rec();
1649 }
1650 
1651 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1652                                     int filter_hash)
1653 {
1654         __ftrace_hash_rec_update(ops, filter_hash, 0);
1655 }
1656 
1657 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1658                                    int filter_hash)
1659 {
1660         __ftrace_hash_rec_update(ops, filter_hash, 1);
1661 }
1662 
1663 static void print_ip_ins(const char *fmt, unsigned char *p)
1664 {
1665         int i;
1666 
1667         printk(KERN_CONT "%s", fmt);
1668 
1669         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1670                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1671 }
1672 
1673 /**
1674  * ftrace_bug - report and shutdown function tracer
1675  * @failed: The failed type (EFAULT, EINVAL, EPERM)
1676  * @ip: The address that failed
1677  *
1678  * The arch code that enables or disables the function tracing
1679  * can call ftrace_bug() when it has detected a problem in
1680  * modifying the code. @failed should be one of either:
1681  * EFAULT - if the problem happens on reading the @ip address
1682  * EINVAL - if what is read at @ip is not what was expected
1683  * EPERM - if the problem happens on writting to the @ip address
1684  */
1685 void ftrace_bug(int failed, unsigned long ip)
1686 {
1687         switch (failed) {
1688         case -EFAULT:
1689                 FTRACE_WARN_ON_ONCE(1);
1690                 pr_info("ftrace faulted on modifying ");
1691                 print_ip_sym(ip);
1692                 break;
1693         case -EINVAL:
1694                 FTRACE_WARN_ON_ONCE(1);
1695                 pr_info("ftrace failed to modify ");
1696                 print_ip_sym(ip);
1697                 print_ip_ins(" actual: ", (unsigned char *)ip);
1698                 printk(KERN_CONT "\n");
1699                 break;
1700         case -EPERM:
1701                 FTRACE_WARN_ON_ONCE(1);
1702                 pr_info("ftrace faulted on writing ");
1703                 print_ip_sym(ip);
1704                 break;
1705         default:
1706                 FTRACE_WARN_ON_ONCE(1);
1707                 pr_info("ftrace faulted on unknown error ");
1708                 print_ip_sym(ip);
1709         }
1710 }
1711 
1712 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1713 {
1714         unsigned long flag = 0UL;
1715 
1716         /*
1717          * If we are updating calls:
1718          *
1719          *   If the record has a ref count, then we need to enable it
1720          *   because someone is using it.
1721          *
1722          *   Otherwise we make sure its disabled.
1723          *
1724          * If we are disabling calls, then disable all records that
1725          * are enabled.
1726          */
1727         if (enable && (rec->flags & ~FTRACE_FL_MASK))
1728                 flag = FTRACE_FL_ENABLED;
1729 
1730         /*
1731          * If enabling and the REGS flag does not match the REGS_EN, then
1732          * do not ignore this record. Set flags to fail the compare against
1733          * ENABLED.
1734          */
1735         if (flag &&
1736             (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
1737                 flag |= FTRACE_FL_REGS;
1738 
1739         /* If the state of this record hasn't changed, then do nothing */
1740         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1741                 return FTRACE_UPDATE_IGNORE;
1742 
1743         if (flag) {
1744                 /* Save off if rec is being enabled (for return value) */
1745                 flag ^= rec->flags & FTRACE_FL_ENABLED;
1746 
1747                 if (update) {
1748                         rec->flags |= FTRACE_FL_ENABLED;
1749                         if (flag & FTRACE_FL_REGS) {
1750                                 if (rec->flags & FTRACE_FL_REGS)
1751                                         rec->flags |= FTRACE_FL_REGS_EN;
1752                                 else
1753                                         rec->flags &= ~FTRACE_FL_REGS_EN;
1754                         }
1755                 }
1756 
1757                 /*
1758                  * If this record is being updated from a nop, then
1759                  *   return UPDATE_MAKE_CALL.
1760                  * Otherwise, if the EN flag is set, then return
1761                  *   UPDATE_MODIFY_CALL_REGS to tell the caller to convert
1762                  *   from the non-save regs, to a save regs function.
1763                  * Otherwise,
1764                  *   return UPDATE_MODIFY_CALL to tell the caller to convert
1765                  *   from the save regs, to a non-save regs function.
1766                  */
1767                 if (flag & FTRACE_FL_ENABLED)
1768                         return FTRACE_UPDATE_MAKE_CALL;
1769                 else if (rec->flags & FTRACE_FL_REGS_EN)
1770                         return FTRACE_UPDATE_MODIFY_CALL_REGS;
1771                 else
1772                         return FTRACE_UPDATE_MODIFY_CALL;
1773         }
1774 
1775         if (update) {
1776                 /* If there's no more users, clear all flags */
1777                 if (!(rec->flags & ~FTRACE_FL_MASK))
1778                         rec->flags = 0;
1779                 else
1780                         /* Just disable the record (keep REGS state) */
1781                         rec->flags &= ~FTRACE_FL_ENABLED;
1782         }
1783 
1784         return FTRACE_UPDATE_MAKE_NOP;
1785 }
1786 
1787 /**
1788  * ftrace_update_record, set a record that now is tracing or not
1789  * @rec: the record to update
1790  * @enable: set to 1 if the record is tracing, zero to force disable
1791  *
1792  * The records that represent all functions that can be traced need
1793  * to be updated when tracing has been enabled.
1794  */
1795 int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1796 {
1797         return ftrace_check_record(rec, enable, 1);
1798 }
1799 
1800 /**
1801  * ftrace_test_record, check if the record has been enabled or not
1802  * @rec: the record to test
1803  * @enable: set to 1 to check if enabled, 0 if it is disabled
1804  *
1805  * The arch code may need to test if a record is already set to
1806  * tracing to determine how to modify the function code that it
1807  * represents.
1808  */
1809 int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1810 {
1811         return ftrace_check_record(rec, enable, 0);
1812 }
1813 
1814 static int
1815 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1816 {
1817         unsigned long ftrace_old_addr;
1818         unsigned long ftrace_addr;
1819         int ret;
1820 
1821         ret = ftrace_update_record(rec, enable);
1822 
1823         if (rec->flags & FTRACE_FL_REGS)
1824                 ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
1825         else
1826                 ftrace_addr = (unsigned long)FTRACE_ADDR;
1827 
1828         switch (ret) {
1829         case FTRACE_UPDATE_IGNORE:
1830                 return 0;
1831 
1832         case FTRACE_UPDATE_MAKE_CALL:
1833                 return ftrace_make_call(rec, ftrace_addr);
1834 
1835         case FTRACE_UPDATE_MAKE_NOP:
1836                 return ftrace_make_nop(NULL, rec, ftrace_addr);
1837 
1838         case FTRACE_UPDATE_MODIFY_CALL_REGS:
1839         case FTRACE_UPDATE_MODIFY_CALL:
1840                 if (rec->flags & FTRACE_FL_REGS)
1841                         ftrace_old_addr = (unsigned long)FTRACE_ADDR;
1842                 else
1843                         ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
1844 
1845                 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
1846         }
1847 
1848         return -1; /* unknow ftrace bug */
1849 }
1850 
1851 void __weak ftrace_replace_code(int enable)
1852 {
1853         struct dyn_ftrace *rec;
1854         struct ftrace_page *pg;
1855         int failed;
1856 
1857         if (unlikely(ftrace_disabled))
1858                 return;
1859 
1860         do_for_each_ftrace_rec(pg, rec) {
1861                 failed = __ftrace_replace_code(rec, enable);
1862                 if (failed) {
1863                         ftrace_bug(failed, rec->ip);
1864                         /* Stop processing */
1865                         return;
1866                 }
1867         } while_for_each_ftrace_rec();
1868 }
1869 
1870 struct ftrace_rec_iter {
1871         struct ftrace_page      *pg;
1872         int                     index;
1873 };
1874 
1875 /**
1876  * ftrace_rec_iter_start, start up iterating over traced functions
1877  *
1878  * Returns an iterator handle that is used to iterate over all
1879  * the records that represent address locations where functions
1880  * are traced.
1881  *
1882  * May return NULL if no records are available.
1883  */
1884 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1885 {
1886         /*
1887          * We only use a single iterator.
1888          * Protected by the ftrace_lock mutex.
1889          */
1890         static struct ftrace_rec_iter ftrace_rec_iter;
1891         struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1892 
1893         iter->pg = ftrace_pages_start;
1894         iter->index = 0;
1895 
1896         /* Could have empty pages */
1897         while (iter->pg && !iter->pg->index)
1898                 iter->pg = iter->pg->next;
1899 
1900         if (!iter->pg)
1901                 return NULL;
1902 
1903         return iter;
1904 }
1905 
1906 /**
1907  * ftrace_rec_iter_next, get the next record to process.
1908  * @iter: The handle to the iterator.
1909  *
1910  * Returns the next iterator after the given iterator @iter.
1911  */
1912 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1913 {
1914         iter->index++;
1915 
1916         if (iter->index >= iter->pg->index) {
1917                 iter->pg = iter->pg->next;
1918                 iter->index = 0;
1919 
1920                 /* Could have empty pages */
1921                 while (iter->pg && !iter->pg->index)
1922                         iter->pg = iter->pg->next;
1923         }
1924 
1925         if (!iter->pg)
1926                 return NULL;
1927 
1928         return iter;
1929 }
1930 
1931 /**
1932  * ftrace_rec_iter_record, get the record at the iterator location
1933  * @iter: The current iterator location
1934  *
1935  * Returns the record that the current @iter is at.
1936  */
1937 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1938 {
1939         return &iter->pg->records[iter->index];
1940 }
1941 
1942 static int
1943 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1944 {
1945         unsigned long ip;
1946         int ret;
1947 
1948         ip = rec->ip;
1949 
1950         if (unlikely(ftrace_disabled))
1951                 return 0;
1952 
1953         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1954         if (ret) {
1955                 ftrace_bug(ret, ip);
1956                 return 0;
1957         }
1958         return 1;
1959 }
1960 
1961 /*
1962  * archs can override this function if they must do something
1963  * before the modifying code is performed.
1964  */
1965 int __weak ftrace_arch_code_modify_prepare(void)
1966 {
1967         return 0;
1968 }
1969 
1970 /*
1971  * archs can override this function if they must do something
1972  * after the modifying code is performed.
1973  */
1974 int __weak ftrace_arch_code_modify_post_process(void)
1975 {
1976         return 0;
1977 }
1978 
1979 void ftrace_modify_all_code(int command)
1980 {
1981         if (command & FTRACE_UPDATE_CALLS)
1982                 ftrace_replace_code(1);
1983         else if (command & FTRACE_DISABLE_CALLS)
1984                 ftrace_replace_code(0);
1985 
1986         if (command & FTRACE_UPDATE_TRACE_FUNC)
1987                 ftrace_update_ftrace_func(ftrace_trace_function);
1988 
1989         if (command & FTRACE_START_FUNC_RET)
1990                 ftrace_enable_ftrace_graph_caller();
1991         else if (command & FTRACE_STOP_FUNC_RET)
1992                 ftrace_disable_ftrace_graph_caller();
1993 }
1994 
1995 static int __ftrace_modify_code(void *data)
1996 {
1997         int *command = data;
1998 
1999         ftrace_modify_all_code(*command);
2000 
2001         return 0;
2002 }
2003 
2004 /**
2005  * ftrace_run_stop_machine, go back to the stop machine method
2006  * @command: The command to tell ftrace what to do
2007  *
2008  * If an arch needs to fall back to the stop machine method, the
2009  * it can call this function.
2010  */
2011 void ftrace_run_stop_machine(int command)
2012 {
2013         stop_machine(__ftrace_modify_code, &command, NULL);
2014 }
2015 
2016 /**
2017  * arch_ftrace_update_code, modify the code to trace or not trace
2018  * @command: The command that needs to be done
2019  *
2020  * Archs can override this function if it does not need to
2021  * run stop_machine() to modify code.
2022  */
2023 void __weak arch_ftrace_update_code(int command)
2024 {
2025         ftrace_run_stop_machine(command);
2026 }
2027 
2028 static void ftrace_run_update_code(int command)
2029 {
2030         int ret;
2031 
2032         ret = ftrace_arch_code_modify_prepare();
2033         FTRACE_WARN_ON(ret);
2034         if (ret)
2035                 return;
2036         /*
2037          * Do not call function tracer while we update the code.
2038          * We are in stop machine.
2039          */
2040         function_trace_stop++;
2041 
2042         /*
2043          * By default we use stop_machine() to modify the code.
2044          * But archs can do what ever they want as long as it
2045          * is safe. The stop_machine() is the safest, but also
2046          * produces the most overhead.
2047          */
2048         arch_ftrace_update_code(command);
2049 
2050         function_trace_stop--;
2051 
2052         ret = ftrace_arch_code_modify_post_process();
2053         FTRACE_WARN_ON(ret);
2054 }
2055 
2056 static ftrace_func_t saved_ftrace_func;
2057 static int ftrace_start_up;
2058 static int global_start_up;
2059 
2060 static void ftrace_startup_enable(int command)
2061 {
2062         if (saved_ftrace_func != ftrace_trace_function) {
2063                 saved_ftrace_func = ftrace_trace_function;
2064                 command |= FTRACE_UPDATE_TRACE_FUNC;
2065         }
2066 
2067         if (!command || !ftrace_enabled)
2068                 return;
2069 
2070         ftrace_run_update_code(command);
2071 }
2072 
2073 static int ftrace_startup(struct ftrace_ops *ops, int command)
2074 {
2075         bool hash_enable = true;
2076 
2077         if (unlikely(ftrace_disabled))
2078                 return -ENODEV;
2079 
2080         ftrace_start_up++;
2081         command |= FTRACE_UPDATE_CALLS;
2082 
2083         /* ops marked global share the filter hashes */
2084         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2085                 ops = &global_ops;
2086                 /* Don't update hash if global is already set */
2087                 if (global_start_up)
2088                         hash_enable = false;
2089                 global_start_up++;
2090         }
2091 
2092         ops->flags |= FTRACE_OPS_FL_ENABLED;
2093         if (hash_enable)
2094                 ftrace_hash_rec_enable(ops, 1);
2095 
2096         ftrace_startup_enable(command);
2097 
2098         return 0;
2099 }
2100 
2101 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
2102 {
2103         bool hash_disable = true;
2104 
2105         if (unlikely(ftrace_disabled))
2106                 return;
2107 
2108         ftrace_start_up--;
2109         /*
2110          * Just warn in case of unbalance, no need to kill ftrace, it's not
2111          * critical but the ftrace_call callers may be never nopped again after
2112          * further ftrace uses.
2113          */
2114         WARN_ON_ONCE(ftrace_start_up < 0);
2115 
2116         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
2117                 ops = &global_ops;
2118                 global_start_up--;
2119                 WARN_ON_ONCE(global_start_up < 0);
2120                 /* Don't update hash if global still has users */
2121                 if (global_start_up) {
2122                         WARN_ON_ONCE(!ftrace_start_up);
2123                         hash_disable = false;
2124                 }
2125         }
2126 
2127         if (hash_disable)
2128                 ftrace_hash_rec_disable(ops, 1);
2129 
2130         if (ops != &global_ops || !global_start_up)
2131                 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2132 
2133         command |= FTRACE_UPDATE_CALLS;
2134 
2135         if (saved_ftrace_func != ftrace_trace_function) {
2136                 saved_ftrace_func = ftrace_trace_function;
2137                 command |= FTRACE_UPDATE_TRACE_FUNC;
2138         }
2139 
2140         if (!command || !ftrace_enabled)
2141                 return;
2142 
2143         ftrace_run_update_code(command);
2144 }
2145 
2146 static void ftrace_startup_sysctl(void)
2147 {
2148         if (unlikely(ftrace_disabled))
2149                 return;
2150 
2151         /* Force update next time */
2152         saved_ftrace_func = NULL;
2153         /* ftrace_start_up is true if we want ftrace running */
2154         if (ftrace_start_up)
2155                 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2156 }
2157 
2158 static void ftrace_shutdown_sysctl(void)
2159 {
2160         if (unlikely(ftrace_disabled))
2161                 return;
2162 
2163         /* ftrace_start_up is true if ftrace is running */
2164         if (ftrace_start_up)
2165                 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
2166 }
2167 
2168 static cycle_t          ftrace_update_time;
2169 static unsigned long    ftrace_update_cnt;
2170 unsigned long           ftrace_update_tot_cnt;
2171 
2172 static inline int ops_traces_mod(struct ftrace_ops *ops)
2173 {
2174         /*
2175          * Filter_hash being empty will default to trace module.
2176          * But notrace hash requires a test of individual module functions.
2177          */
2178         return ftrace_hash_empty(ops->filter_hash) &&
2179                 ftrace_hash_empty(ops->notrace_hash);
2180 }
2181 
2182 /*
2183  * Check if the current ops references the record.
2184  *
2185  * If the ops traces all functions, then it was already accounted for.
2186  * If the ops does not trace the current record function, skip it.
2187  * If the ops ignores the function via notrace filter, skip it.
2188  */
2189 static inline bool
2190 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2191 {
2192         /* If ops isn't enabled, ignore it */
2193         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2194                 return 0;
2195 
2196         /* If ops traces all mods, we already accounted for it */
2197         if (ops_traces_mod(ops))
2198                 return 0;
2199 
2200         /* The function must be in the filter */
2201         if (!ftrace_hash_empty(ops->filter_hash) &&
2202             !ftrace_lookup_ip(ops->filter_hash, rec->ip))
2203                 return 0;
2204 
2205         /* If in notrace hash, we ignore it too */
2206         if (ftrace_lookup_ip(ops->notrace_hash, rec->ip))
2207                 return 0;
2208 
2209         return 1;
2210 }
2211 
2212 static int referenced_filters(struct dyn_ftrace *rec)
2213 {
2214         struct ftrace_ops *ops;
2215         int cnt = 0;
2216 
2217         for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2218                 if (ops_references_rec(ops, rec))
2219                     cnt++;
2220         }
2221 
2222         return cnt;
2223 }
2224 
2225 static int ftrace_update_code(struct module *mod)
2226 {
2227         struct ftrace_page *pg;
2228         struct dyn_ftrace *p;
2229         cycle_t start, stop;
2230         unsigned long ref = 0;
2231         bool test = false;
2232         int i;
2233 
2234         /*
2235          * When adding a module, we need to check if tracers are
2236          * currently enabled and if they are set to trace all functions.
2237          * If they are, we need to enable the module functions as well
2238          * as update the reference counts for those function records.
2239          */
2240         if (mod) {
2241                 struct ftrace_ops *ops;
2242 
2243                 for (ops = ftrace_ops_list;
2244                      ops != &ftrace_list_end; ops = ops->next) {
2245                         if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2246                                 if (ops_traces_mod(ops))
2247                                         ref++;
2248                                 else
2249                                         test = true;
2250                         }
2251                 }
2252         }
2253 
2254         start = ftrace_now(raw_smp_processor_id());
2255         ftrace_update_cnt = 0;
2256 
2257         for (pg = ftrace_new_pgs; pg; pg = pg->next) {
2258 
2259                 for (i = 0; i < pg->index; i++) {
2260                         int cnt = ref;
2261 
2262                         /* If something went wrong, bail without enabling anything */
2263                         if (unlikely(ftrace_disabled))
2264                                 return -1;
2265 
2266                         p = &pg->records[i];
2267                         if (test)
2268                                 cnt += referenced_filters(p);
2269                         p->flags = cnt;
2270 
2271                         /*
2272                          * Do the initial record conversion from mcount jump
2273                          * to the NOP instructions.
2274                          */
2275                         if (!ftrace_code_disable(mod, p))
2276                                 break;
2277 
2278                         ftrace_update_cnt++;
2279 
2280                         /*
2281                          * If the tracing is enabled, go ahead and enable the record.
2282                          *
2283                          * The reason not to enable the record immediatelly is the
2284                          * inherent check of ftrace_make_nop/ftrace_make_call for
2285                          * correct previous instructions.  Making first the NOP
2286                          * conversion puts the module to the correct state, thus
2287                          * passing the ftrace_make_call check.
2288                          */
2289                         if (ftrace_start_up && cnt) {
2290                                 int failed = __ftrace_replace_code(p, 1);
2291                                 if (failed)
2292                                         ftrace_bug(failed, p->ip);
2293                         }
2294                 }
2295         }
2296 
2297         ftrace_new_pgs = NULL;
2298 
2299         stop = ftrace_now(raw_smp_processor_id());
2300         ftrace_update_time = stop - start;
2301         ftrace_update_tot_cnt += ftrace_update_cnt;
2302 
2303         return 0;
2304 }
2305 
2306 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2307 {
2308         int order;
2309         int cnt;
2310 
2311         if (WARN_ON(!count))
2312                 return -EINVAL;
2313 
2314         order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2315 
2316         /*
2317          * We want to fill as much as possible. No more than a page
2318          * may be empty.
2319          */
2320         while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2321                 order--;
2322 
2323  again:
2324         pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2325 
2326         if (!pg->records) {
2327                 /* if we can't allocate this size, try something smaller */
2328                 if (!order)
2329                         return -ENOMEM;
2330                 order >>= 1;
2331                 goto again;
2332         }
2333 
2334         cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2335         pg->size = cnt;
2336 
2337         if (cnt > count)
2338                 cnt = count;
2339 
2340         return cnt;
2341 }
2342 
2343 static struct ftrace_page *
2344 ftrace_allocate_pages(unsigned long num_to_init)
2345 {
2346         struct ftrace_page *start_pg;
2347         struct ftrace_page *pg;
2348         int order;
2349         int cnt;
2350 
2351         if (!num_to_init)
2352                 return 0;
2353 
2354         start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2355         if (!pg)
2356                 return NULL;
2357 
2358         /*
2359          * Try to allocate as much as possible in one continues
2360          * location that fills in all of the space. We want to
2361          * waste as little space as possible.
2362          */
2363         for (;;) {
2364                 cnt = ftrace_allocate_records(pg, num_to_init);
2365                 if (cnt < 0)
2366                         goto free_pages;
2367 
2368                 num_to_init -= cnt;
2369                 if (!num_to_init)
2370                         break;
2371 
2372                 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2373                 if (!pg->next)
2374                         goto free_pages;
2375 
2376                 pg = pg->next;
2377         }
2378 
2379         return start_pg;
2380 
2381  free_pages:
2382         while (start_pg) {
2383                 order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2384                 free_pages((unsigned long)pg->records, order);
2385                 start_pg = pg->next;
2386                 kfree(pg);
2387                 pg = start_pg;
2388         }
2389         pr_info("ftrace: FAILED to allocate memory for functions\n");
2390         return NULL;
2391 }
2392 
2393 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2394 {
2395         int cnt;
2396 
2397         if (!num_to_init) {
2398                 pr_info("ftrace: No functions to be traced?\n");
2399                 return -1;
2400         }
2401 
2402         cnt = num_to_init / ENTRIES_PER_PAGE;
2403         pr_info("ftrace: allocating %ld entries in %d pages\n",
2404                 num_to_init, cnt + 1);
2405 
2406         return 0;
2407 }
2408 
2409 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2410 
2411 struct ftrace_iterator {
2412         loff_t                          pos;
2413         loff_t                          func_pos;
2414         struct ftrace_page              *pg;
2415         struct dyn_ftrace               *func;
2416         struct ftrace_func_probe        *probe;
2417         struct trace_parser             parser;
2418         struct ftrace_hash              *hash;
2419         struct ftrace_ops               *ops;
2420         int                             hidx;
2421         int                             idx;
2422         unsigned                        flags;
2423 };
2424 
2425 static void *
2426 t_hash_next(struct seq_file *m, loff_t *pos)
2427 {
2428         struct ftrace_iterator *iter = m->private;
2429         struct hlist_node *hnd = NULL;
2430         struct hlist_head *hhd;
2431 
2432         (*pos)++;
2433         iter->pos = *pos;
2434 
2435         if (iter->probe)
2436                 hnd = &iter->probe->node;
2437  retry:
2438         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2439                 return NULL;
2440 
2441         hhd = &ftrace_func_hash[iter->hidx];
2442 
2443         if (hlist_empty(hhd)) {
2444                 iter->hidx++;
2445                 hnd = NULL;
2446                 goto retry;
2447         }
2448 
2449         if (!hnd)
2450                 hnd = hhd->first;
2451         else {
2452                 hnd = hnd->next;
2453                 if (!hnd) {
2454                         iter->hidx++;
2455                         goto retry;
2456                 }
2457         }
2458 
2459         if (WARN_ON_ONCE(!hnd))
2460                 return NULL;
2461 
2462         iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2463 
2464         return iter;
2465 }
2466 
2467 static void *t_hash_start(struct seq_file *m, loff_t *pos)
2468 {
2469         struct ftrace_iterator *iter = m->private;
2470         void *p = NULL;
2471         loff_t l;
2472 
2473         if (!(iter->flags & FTRACE_ITER_DO_HASH))
2474                 return NULL;
2475 
2476         if (iter->func_pos > *pos)
2477                 return NULL;
2478 
2479         iter->hidx = 0;
2480         for (l = 0; l <= (*pos - iter->func_pos); ) {
2481                 p = t_hash_next(m, &l);
2482                 if (!p)
2483                         break;
2484         }
2485         if (!p)
2486                 return NULL;
2487 
2488         /* Only set this if we have an item */
2489         iter->flags |= FTRACE_ITER_HASH;
2490 
2491         return iter;
2492 }
2493 
2494 static int
2495 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2496 {
2497         struct ftrace_func_probe *rec;
2498 
2499         rec = iter->probe;
2500         if (WARN_ON_ONCE(!rec))
2501                 return -EIO;
2502 
2503         if (rec->ops->print)
2504                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2505 
2506         seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2507 
2508         if (rec->data)
2509                 seq_printf(m, ":%p", rec->data);
2510         seq_putc(m, '\n');
2511 
2512         return 0;
2513 }
2514 
2515 static void *
2516 t_next(struct seq_file *m, void *v, loff_t *pos)
2517 {
2518         struct ftrace_iterator *iter = m->private;
2519         struct ftrace_ops *ops = iter->ops;
2520         struct dyn_ftrace *rec = NULL;
2521 
2522         if (unlikely(ftrace_disabled))
2523                 return NULL;
2524 
2525         if (iter->flags & FTRACE_ITER_HASH)
2526                 return t_hash_next(m, pos);
2527 
2528         (*pos)++;
2529         iter->pos = iter->func_pos = *pos;
2530 
2531         if (iter->flags & FTRACE_ITER_PRINTALL)
2532                 return t_hash_start(m, pos);
2533 
2534  retry:
2535         if (iter->idx >= iter->pg->index) {
2536                 if (iter->pg->next) {
2537                         iter->pg = iter->pg->next;
2538                         iter->idx = 0;
2539                         goto retry;
2540                 }
2541         } else {
2542                 rec = &iter->pg->records[iter->idx++];
2543                 if (((iter->flags & FTRACE_ITER_FILTER) &&
2544                      !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2545 
2546                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
2547                      !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2548 
2549                     ((iter->flags & FTRACE_ITER_ENABLED) &&
2550                      !(rec->flags & FTRACE_FL_ENABLED))) {
2551 
2552                         rec = NULL;
2553                         goto retry;
2554                 }
2555         }
2556 
2557         if (!rec)
2558                 return t_hash_start(m, pos);
2559 
2560         iter->func = rec;
2561 
2562         return iter;
2563 }
2564 
2565 static void reset_iter_read(struct ftrace_iterator *iter)
2566 {
2567         iter->pos = 0;
2568         iter->func_pos = 0;
2569         iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2570 }
2571 
2572 static void *t_start(struct seq_file *m, loff_t *pos)
2573 {
2574         struct ftrace_iterator *iter = m->private;
2575         struct ftrace_ops *ops = iter->ops;
2576         void *p = NULL;
2577         loff_t l;
2578 
2579         mutex_lock(&ftrace_lock);
2580 
2581         if (unlikely(ftrace_disabled))
2582                 return NULL;
2583 
2584         /*
2585          * If an lseek was done, then reset and start from beginning.
2586          */
2587         if (*pos < iter->pos)
2588                 reset_iter_read(iter);
2589 
2590         /*
2591          * For set_ftrace_filter reading, if we have the filter
2592          * off, we can short cut and just print out that all
2593          * functions are enabled.
2594          */
2595         if (iter->flags & FTRACE_ITER_FILTER &&
2596             ftrace_hash_empty(ops->filter_hash)) {
2597                 if (*pos > 0)
2598                         return t_hash_start(m, pos);
2599                 iter->flags |= FTRACE_ITER_PRINTALL;
2600                 /* reset in case of seek/pread */
2601                 iter->flags &= ~FTRACE_ITER_HASH;
2602                 return iter;
2603         }
2604 
2605         if (iter->flags & FTRACE_ITER_HASH)
2606                 return t_hash_start(m, pos);
2607 
2608         /*
2609          * Unfortunately, we need to restart at ftrace_pages_start
2610          * every time we let go of the ftrace_mutex. This is because
2611          * those pointers can change without the lock.
2612          */
2613         iter->pg = ftrace_pages_start;
2614         iter->idx = 0;
2615         for (l = 0; l <= *pos; ) {
2616                 p = t_next(m, p, &l);
2617                 if (!p)
2618                         break;
2619         }
2620 
2621         if (!p)
2622                 return t_hash_start(m, pos);
2623 
2624         return iter;
2625 }
2626 
2627 static void t_stop(struct seq_file *m, void *p)
2628 {
2629         mutex_unlock(&ftrace_lock);
2630 }
2631 
2632 static int t_show(struct seq_file *m, void *v)
2633 {
2634         struct ftrace_iterator *iter = m->private;
2635         struct dyn_ftrace *rec;
2636 
2637         if (iter->flags & FTRACE_ITER_HASH)
2638                 return t_hash_show(m, iter);
2639 
2640         if (iter->flags & FTRACE_ITER_PRINTALL) {
2641                 seq_printf(m, "#### all functions enabled ####\n");
2642                 return 0;
2643         }
2644 
2645         rec = iter->func;
2646 
2647         if (!rec)
2648                 return 0;
2649 
2650         seq_printf(m, "%ps", (void *)rec->ip);
2651         if (iter->flags & FTRACE_ITER_ENABLED)
2652                 seq_printf(m, " (%ld)%s",
2653                            rec->flags & ~FTRACE_FL_MASK,
2654                            rec->flags & FTRACE_FL_REGS ? " R" : "");
2655         seq_printf(m, "\n");
2656 
2657         return 0;
2658 }
2659 
2660 static const struct seq_operations show_ftrace_seq_ops = {
2661         .start = t_start,
2662         .next = t_next,
2663         .stop = t_stop,
2664         .show = t_show,
2665 };
2666 
2667 static int
2668 ftrace_avail_open(struct inode *inode, struct file *file)
2669 {
2670         struct ftrace_iterator *iter;
2671 
2672         if (unlikely(ftrace_disabled))
2673                 return -ENODEV;
2674 
2675         iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2676         if (iter) {
2677                 iter->pg = ftrace_pages_start;
2678                 iter->ops = &global_ops;
2679         }
2680 
2681         return iter ? 0 : -ENOMEM;
2682 }
2683 
2684 static int
2685 ftrace_enabled_open(struct inode *inode, struct file *file)
2686 {
2687         struct ftrace_iterator *iter;
2688 
2689         if (unlikely(ftrace_disabled))
2690                 return -ENODEV;
2691 
2692         iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2693         if (iter) {
2694                 iter->pg = ftrace_pages_start;
2695                 iter->flags = FTRACE_ITER_ENABLED;
2696                 iter->ops = &global_ops;
2697         }
2698 
2699         return iter ? 0 : -ENOMEM;
2700 }
2701 
2702 static void ftrace_filter_reset(struct ftrace_hash *hash)
2703 {
2704         mutex_lock(&ftrace_lock);
2705         ftrace_hash_clear(hash);
2706         mutex_unlock(&ftrace_lock);
2707 }
2708 
2709 /**
2710  * ftrace_regex_open - initialize function tracer filter files
2711  * @ops: The ftrace_ops that hold the hash filters
2712  * @flag: The type of filter to process
2713  * @inode: The inode, usually passed in to your open routine
2714  * @file: The file, usually passed in to your open routine
2715  *
2716  * ftrace_regex_open() initializes the filter files for the
2717  * @ops. Depending on @flag it may process the filter hash or
2718  * the notrace hash of @ops. With this called from the open
2719  * routine, you can use ftrace_filter_write() for the write
2720  * routine if @flag has FTRACE_ITER_FILTER set, or
2721  * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2722  * ftrace_filter_lseek() should be used as the lseek routine, and
2723  * release must call ftrace_regex_release().
2724  */
2725 int
2726 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2727                   struct inode *inode, struct file *file)
2728 {
2729         struct ftrace_iterator *iter;
2730         struct ftrace_hash *hash;
2731         int ret = 0;
2732 
2733         ftrace_ops_init(ops);
2734 
2735         if (unlikely(ftrace_disabled))
2736                 return -ENODEV;
2737 
2738         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2739         if (!iter)
2740                 return -ENOMEM;
2741 
2742         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2743                 kfree(iter);
2744                 return -ENOMEM;
2745         }
2746 
2747         iter->ops = ops;
2748         iter->flags = flag;
2749 
2750         mutex_lock(&ops->regex_lock);
2751 
2752         if (flag & FTRACE_ITER_NOTRACE)
2753                 hash = ops->notrace_hash;
2754         else
2755                 hash = ops->filter_hash;
2756 
2757         if (file->f_mode & FMODE_WRITE) {
2758                 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2759                 if (!iter->hash) {
2760                         trace_parser_put(&iter->parser);
2761                         kfree(iter);
2762                         ret = -ENOMEM;
2763                         goto out_unlock;
2764                 }
2765         }
2766 
2767         if ((file->f_mode & FMODE_WRITE) &&
2768             (file->f_flags & O_TRUNC))
2769                 ftrace_filter_reset(iter->hash);
2770 
2771         if (file->f_mode & FMODE_READ) {
2772                 iter->pg = ftrace_pages_start;
2773 
2774                 ret = seq_open(file, &show_ftrace_seq_ops);
2775                 if (!ret) {
2776                         struct seq_file *m = file->private_data;
2777                         m->private = iter;
2778                 } else {
2779                         /* Failed */
2780                         free_ftrace_hash(iter->hash);
2781                         trace_parser_put(&iter->parser);
2782                         kfree(iter);
2783                 }
2784         } else
2785                 file->private_data = iter;
2786 
2787  out_unlock:
2788         mutex_unlock(&ops->regex_lock);
2789 
2790         return ret;
2791 }
2792 
2793 static int
2794 ftrace_filter_open(struct inode *inode, struct file *file)
2795 {
2796         return ftrace_regex_open(&global_ops,
2797                         FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
2798                         inode, file);
2799 }
2800 
2801 static int
2802 ftrace_notrace_open(struct inode *inode, struct file *file)
2803 {
2804         return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2805                                  inode, file);
2806 }
2807 
2808 static int ftrace_match(char *str, char *regex, int len, int type)
2809 {
2810         int matched = 0;
2811         int slen;
2812 
2813         switch (type) {
2814         case MATCH_FULL:
2815                 if (strcmp(str, regex) == 0)
2816                         matched = 1;
2817                 break;
2818         case MATCH_FRONT_ONLY:
2819                 if (strncmp(str, regex, len) == 0)
2820                         matched = 1;
2821                 break;
2822         case MATCH_MIDDLE_ONLY:
2823                 if (strstr(str, regex))
2824                         matched = 1;
2825                 break;
2826         case MATCH_END_ONLY:
2827                 slen = strlen(str);
2828                 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2829                         matched = 1;
2830                 break;
2831         }
2832 
2833         return matched;
2834 }
2835 
2836 static int
2837 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2838 {
2839         struct ftrace_func_entry *entry;
2840         int ret = 0;
2841 
2842         entry = ftrace_lookup_ip(hash, rec->ip);
2843         if (not) {
2844                 /* Do nothing if it doesn't exist */
2845                 if (!entry)
2846                         return 0;
2847 
2848                 free_hash_entry(hash, entry);
2849         } else {
2850                 /* Do nothing if it exists */
2851                 if (entry)
2852                         return 0;
2853 
2854                 ret = add_hash_entry(hash, rec->ip);
2855         }
2856         return ret;
2857 }
2858 
2859 static int
2860 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2861                     char *regex, int len, int type)
2862 {
2863         char str[KSYM_SYMBOL_LEN];
2864         char *modname;
2865 
2866         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2867 
2868         if (mod) {
2869                 /* module lookup requires matching the module */
2870                 if (!modname || strcmp(modname, mod))
2871                         return 0;
2872 
2873                 /* blank search means to match all funcs in the mod */
2874                 if (!len)
2875                         return 1;
2876         }
2877 
2878         return ftrace_match(str, regex, len, type);
2879 }
2880 
2881 static int
2882 match_records(struct ftrace_hash *hash, char *buff,
2883               int len, char *mod, int not)
2884 {
2885         unsigned search_len = 0;
2886         struct ftrace_page *pg;
2887         struct dyn_ftrace *rec;
2888         int type = MATCH_FULL;
2889         char *search = buff;
2890         int found = 0;
2891         int ret;
2892 
2893         if (len) {
2894                 type = filter_parse_regex(buff, len, &search, &not);
2895                 search_len = strlen(search);
2896         }
2897 
2898         mutex_lock(&ftrace_lock);
2899 
2900         if (unlikely(ftrace_disabled))
2901                 goto out_unlock;
2902 
2903         do_for_each_ftrace_rec(pg, rec) {
2904                 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2905                         ret = enter_record(hash, rec, not);
2906                         if (ret < 0) {
2907                                 found = ret;
2908                                 goto out_unlock;
2909                         }
2910                         found = 1;
2911                 }
2912         } while_for_each_ftrace_rec();
2913  out_unlock:
2914         mutex_unlock(&ftrace_lock);
2915 
2916         return found;
2917 }
2918 
2919 static int
2920 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2921 {
2922         return match_records(hash, buff, len, NULL, 0);
2923 }
2924 
2925 static int
2926 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2927 {
2928         int not = 0;
2929 
2930         /* blank or '*' mean the same */
2931         if (strcmp(buff, "*") == 0)
2932                 buff[0] = 0;
2933 
2934         /* handle the case of 'dont filter this module' */
2935         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2936                 buff[0] = 0;
2937                 not = 1;
2938         }
2939 
2940         return match_records(hash, buff, strlen(buff), mod, not);
2941 }
2942 
2943 /*
2944  * We register the module command as a template to show others how
2945  * to register the a command as well.
2946  */
2947 
2948 static int
2949 ftrace_mod_callback(struct ftrace_hash *hash,
2950                     char *func, char *cmd, char *param, int enable)
2951 {
2952         char *mod;
2953         int ret = -EINVAL;
2954 
2955         /*
2956          * cmd == 'mod' because we only registered this func
2957          * for the 'mod' ftrace_func_command.
2958          * But if you register one func with multiple commands,
2959          * you can tell which command was used by the cmd
2960          * parameter.
2961          */
2962 
2963         /* we must have a module name */
2964         if (!param)
2965                 return ret;
2966 
2967         mod = strsep(&param, ":");
2968         if (!strlen(mod))
2969                 return ret;
2970 
2971         ret = ftrace_match_module_records(hash, func, mod);
2972         if (!ret)
2973                 ret = -EINVAL;
2974         if (ret < 0)
2975                 return ret;
2976 
2977         return 0;
2978 }
2979 
2980 static struct ftrace_func_command ftrace_mod_cmd = {
2981         .name                   = "mod",
2982         .func                   = ftrace_mod_callback,
2983 };
2984 
2985 static int __init ftrace_mod_cmd_init(void)
2986 {
2987         return register_ftrace_command(&ftrace_mod_cmd);
2988 }
2989 core_initcall(ftrace_mod_cmd_init);
2990 
2991 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
2992                                       struct ftrace_ops *op, struct pt_regs *pt_regs)
2993 {
2994         struct ftrace_func_probe *entry;
2995         struct hlist_head *hhd;
2996         unsigned long key;
2997 
2998         key = hash_long(ip, FTRACE_HASH_BITS);
2999 
3000         hhd = &ftrace_func_hash[key];
3001 
3002         if (hlist_empty(hhd))
3003                 return;
3004 
3005         /*
3006          * Disable preemption for these calls to prevent a RCU grace
3007          * period. This syncs the hash iteration and freeing of items
3008          * on the hash. rcu_read_lock is too dangerous here.
3009          */
3010         preempt_disable_notrace();
3011         hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3012                 if (entry->ip == ip)
3013                         entry->ops->func(ip, parent_ip, &entry->data);
3014         }
3015         preempt_enable_notrace();
3016 }
3017 
3018 static struct ftrace_ops trace_probe_ops __read_mostly =
3019 {
3020         .func           = function_trace_probe_call,
3021         .flags          = FTRACE_OPS_FL_INITIALIZED,
3022         INIT_REGEX_LOCK(trace_probe_ops)
3023 };
3024 
3025 static int ftrace_probe_registered;
3026 
3027 static void __enable_ftrace_function_probe(void)
3028 {
3029         int ret;
3030         int i;
3031 
3032         if (ftrace_probe_registered) {
3033                 /* still need to update the function call sites */
3034                 if (ftrace_enabled)
3035                         ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3036                 return;
3037         }
3038 
3039         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3040                 struct hlist_head *hhd = &ftrace_func_hash[i];
3041                 if (hhd->first)
3042                         break;
3043         }
3044         /* Nothing registered? */
3045         if (i == FTRACE_FUNC_HASHSIZE)
3046                 return;
3047 
3048         ret = __register_ftrace_function(&trace_probe_ops);
3049         if (!ret)
3050                 ret = ftrace_startup(&trace_probe_ops, 0);
3051 
3052         ftrace_probe_registered = 1;
3053 }
3054 
3055 static void __disable_ftrace_function_probe(void)
3056 {
3057         int ret;
3058         int i;
3059 
3060         if (!ftrace_probe_registered)
3061                 return;
3062 
3063         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3064                 struct hlist_head *hhd = &ftrace_func_hash[i];
3065                 if (hhd->first)
3066                         return;
3067         }
3068 
3069         /* no more funcs left */
3070         ret = __unregister_ftrace_function(&trace_probe_ops);
3071         if (!ret)
3072                 ftrace_shutdown(&trace_probe_ops, 0);
3073 
3074         ftrace_probe_registered = 0;
3075 }
3076 
3077 
3078 static void ftrace_free_entry(struct ftrace_func_probe *entry)
3079 {
3080         if (entry->ops->free)
3081                 entry->ops->free(entry->ops, entry->ip, &entry->data);
3082         kfree(entry);
3083 }
3084 
3085 int
3086 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3087                               void *data)
3088 {
3089         struct ftrace_func_probe *entry;
3090         struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3091         struct ftrace_hash *hash;
3092         struct ftrace_page *pg;
3093         struct dyn_ftrace *rec;
3094         int type, len, not;
3095         unsigned long key;
3096         int count = 0;
3097         char *search;
3098         int ret;
3099 
3100         type = filter_parse_regex(glob, strlen(glob), &search, &not);
3101         len = strlen(search);
3102 
3103         /* we do not support '!' for function probes */
3104         if (WARN_ON(not))
3105                 return -EINVAL;
3106 
3107         mutex_lock(&trace_probe_ops.regex_lock);
3108 
3109         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3110         if (!hash) {
3111                 count = -ENOMEM;
3112                 goto out;
3113         }
3114 
3115         if (unlikely(ftrace_disabled)) {
3116                 count = -ENODEV;
3117                 goto out;
3118         }
3119 
3120         mutex_lock(&ftrace_lock);
3121 
3122         do_for_each_ftrace_rec(pg, rec) {
3123 
3124                 if (!ftrace_match_record(rec, NULL, search, len, type))
3125                         continue;
3126 
3127                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3128                 if (!entry) {
3129                         /* If we did not process any, then return error */
3130                         if (!count)
3131                                 count = -ENOMEM;
3132                         goto out_unlock;
3133                 }
3134 
3135                 count++;
3136 
3137                 entry->data = data;
3138 
3139                 /*
3140                  * The caller might want to do something special
3141                  * for each function we find. We call the callback
3142                  * to give the caller an opportunity to do so.
3143                  */
3144                 if (ops->init) {
3145                         if (ops->init(ops, rec->ip, &entry->data) < 0) {
3146                                 /* caller does not like this func */
3147                                 kfree(entry);
3148                                 continue;
3149                         }
3150                 }
3151 
3152                 ret = enter_record(hash, rec, 0);
3153                 if (ret < 0) {
3154                         kfree(entry);
3155                         count = ret;
3156                         goto out_unlock;
3157                 }
3158 
3159                 entry->ops = ops;
3160                 entry->ip = rec->ip;
3161 
3162                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
3163                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3164 
3165         } while_for_each_ftrace_rec();
3166 
3167         ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3168         if (ret < 0)
3169                 count = ret;
3170 
3171         __enable_ftrace_function_probe();
3172 
3173  out_unlock:
3174         mutex_unlock(&ftrace_lock);
3175  out:
3176         mutex_unlock(&trace_probe_ops.regex_lock);
3177         free_ftrace_hash(hash);
3178 
3179         return count;
3180 }
3181 
3182 enum {
3183         PROBE_TEST_FUNC         = 1,
3184         PROBE_TEST_DATA         = 2
3185 };
3186 
3187 static void
3188 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3189                                   void *data, int flags)
3190 {
3191         struct ftrace_func_entry *rec_entry;
3192         struct ftrace_func_probe *entry;
3193         struct ftrace_func_probe *p;
3194         struct ftrace_hash **orig_hash = &trace_probe_ops.filter_hash;
3195         struct list_head free_list;
3196         struct ftrace_hash *hash;
3197         struct hlist_node *tmp;
3198         char str[KSYM_SYMBOL_LEN];
3199         int type = MATCH_FULL;
3200         int i, len = 0;
3201         char *search;
3202 
3203         if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3204                 glob = NULL;
3205         else if (glob) {
3206                 int not;
3207 
3208                 type = filter_parse_regex(glob, strlen(glob), &search, &not);
3209                 len = strlen(search);
3210 
3211                 /* we do not support '!' for function probes */
3212                 if (WARN_ON(not))
3213                         return;
3214         }
3215 
3216         mutex_lock(&trace_probe_ops.regex_lock);
3217 
3218         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3219         if (!hash)
3220                 /* Hmm, should report this somehow */
3221                 goto out_unlock;
3222 
3223         INIT_LIST_HEAD(&free_list);
3224 
3225         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3226                 struct hlist_head *hhd = &ftrace_func_hash[i];
3227 
3228                 hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3229 
3230                         /* break up if statements for readability */
3231                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3232                                 continue;
3233 
3234                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
3235                                 continue;
3236 
3237                         /* do this last, since it is the most expensive */
3238                         if (glob) {
3239                                 kallsyms_lookup(entry->ip, NULL, NULL,
3240                                                 NULL, str);
3241                                 if (!ftrace_match(str, glob, len, type))
3242                                         continue;
3243                         }
3244 
3245                         rec_entry = ftrace_lookup_ip(hash, entry->ip);
3246                         /* It is possible more than one entry had this ip */
3247                         if (rec_entry)
3248                                 free_hash_entry(hash, rec_entry);
3249 
3250                         hlist_del_rcu(&entry->node);
3251                         list_add(&entry->free_list, &free_list);
3252                 }
3253         }
3254         mutex_lock(&ftrace_lock);
3255         __disable_ftrace_function_probe();
3256         /*
3257          * Remove after the disable is called. Otherwise, if the last
3258          * probe is removed, a null hash means *all enabled*.
3259          */
3260         ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3261         synchronize_sched();
3262         list_for_each_entry_safe(entry, p, &free_list, free_list) {
3263                 list_del(&entry->free_list);
3264                 ftrace_free_entry(entry);
3265         }
3266         mutex_unlock(&ftrace_lock);
3267                 
3268  out_unlock:
3269         mutex_unlock(&trace_probe_ops.regex_lock);
3270         free_ftrace_hash(hash);
3271 }
3272 
3273 void
3274 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3275                                 void *data)
3276 {
3277         __unregister_ftrace_function_probe(glob, ops, data,
3278                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
3279 }
3280 
3281 void
3282 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3283 {
3284         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3285 }
3286 
3287 void unregister_ftrace_function_probe_all(char *glob)
3288 {
3289         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3290 }
3291 
3292 static LIST_HEAD(ftrace_commands);
3293 static DEFINE_MUTEX(ftrace_cmd_mutex);
3294 
3295 int register_ftrace_command(struct ftrace_func_command *cmd)
3296 {
3297         struct ftrace_func_command *p;
3298         int ret = 0;
3299 
3300         mutex_lock(&ftrace_cmd_mutex);
3301         list_for_each_entry(p, &ftrace_commands, list) {
3302                 if (strcmp(cmd->name, p->name) == 0) {
3303                         ret = -EBUSY;
3304                         goto out_unlock;
3305                 }
3306         }
3307         list_add(&cmd->list, &ftrace_commands);
3308  out_unlock:
3309         mutex_unlock(&ftrace_cmd_mutex);
3310 
3311         return ret;
3312 }
3313 
3314 int unregister_ftrace_command(struct ftrace_func_command *cmd)
3315 {
3316         struct ftrace_func_command *p, *n;
3317         int ret = -ENODEV;
3318 
3319         mutex_lock(&ftrace_cmd_mutex);
3320         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3321                 if (strcmp(cmd->name, p->name) == 0) {
3322                         ret = 0;
3323                         list_del_init(&p->list);
3324                         goto out_unlock;
3325                 }
3326         }
3327  out_unlock:
3328         mutex_unlock(&ftrace_cmd_mutex);
3329 
3330         return ret;
3331 }
3332 
3333 static int ftrace_process_regex(struct ftrace_hash *hash,
3334                                 char *buff, int len, int enable)
3335 {
3336         char *func, *command, *next = buff;
3337         struct ftrace_func_command *p;
3338         int ret = -EINVAL;
3339 
3340         func = strsep(&next, ":");
3341 
3342         if (!next) {
3343                 ret = ftrace_match_records(hash, func, len);
3344                 if (!ret)
3345                         ret = -EINVAL;
3346                 if (ret < 0)
3347                         return ret;
3348                 return 0;
3349         }
3350 
3351         /* command found */
3352 
3353         command = strsep(&next, ":");
3354 
3355         mutex_lock(&ftrace_cmd_mutex);
3356         list_for_each_entry(p, &ftrace_commands, list) {
3357                 if (strcmp(p->name, command) == 0) {
3358                         ret = p->func(hash, func, command, next, enable);
3359                         goto out_unlock;
3360                 }
3361         }
3362  out_unlock:
3363         mutex_unlock(&ftrace_cmd_mutex);
3364 
3365         return ret;
3366 }
3367 
3368 static ssize_t
3369 ftrace_regex_write(struct file *file, const char __user *ubuf,
3370                    size_t cnt, loff_t *ppos, int enable)
3371 {
3372         struct ftrace_iterator *iter;
3373         struct trace_parser *parser;
3374         ssize_t ret, read;
3375 
3376         if (!cnt)
3377                 return 0;
3378 
3379         if (file->f_mode & FMODE_READ) {
3380                 struct seq_file *m = file->private_data;
3381                 iter = m->private;
3382         } else
3383                 iter = file->private_data;
3384 
3385         if (unlikely(ftrace_disabled))
3386                 return -ENODEV;
3387 
3388         /* iter->hash is a local copy, so we don't need regex_lock */
3389 
3390         parser = &iter->parser;
3391         read = trace_get_user(parser, ubuf, cnt, ppos);
3392 
3393         if (read >= 0 && trace_parser_loaded(parser) &&
3394             !trace_parser_cont(parser)) {
3395                 ret = ftrace_process_regex(iter->hash, parser->buffer,
3396                                            parser->idx, enable);
3397                 trace_parser_clear(parser);
3398                 if (ret < 0)
3399                         goto out;
3400         }
3401 
3402         ret = read;
3403  out:
3404         return ret;
3405 }
3406 
3407 ssize_t
3408 ftrace_filter_write(struct file *file, const char __user *ubuf,
3409                     size_t cnt, loff_t *ppos)
3410 {
3411         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3412 }
3413 
3414 ssize_t
3415 ftrace_notrace_write(struct file *file, const char __user *ubuf,
3416                      size_t cnt, loff_t *ppos)
3417 {
3418         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3419 }
3420 
3421 static int
3422 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3423 {
3424         struct ftrace_func_entry *entry;
3425 
3426         if (!ftrace_location(ip))
3427                 return -EINVAL;
3428 
3429         if (remove) {
3430                 entry = ftrace_lookup_ip(hash, ip);
3431                 if (!entry)
3432                         return -ENOENT;
3433                 free_hash_entry(hash, entry);
3434                 return 0;
3435         }
3436 
3437         return add_hash_entry(hash, ip);
3438 }
3439 
3440 static void ftrace_ops_update_code(struct ftrace_ops *ops)
3441 {
3442         if (ops->flags & FTRACE_OPS_FL_ENABLED && ftrace_enabled)
3443                 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3444 }
3445 
3446 static int
3447 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3448                 unsigned long ip, int remove, int reset, int enable)
3449 {
3450         struct ftrace_hash **orig_hash;
3451         struct ftrace_hash *hash;
3452         int ret;
3453 
3454         /* All global ops uses the global ops filters */
3455         if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3456                 ops = &global_ops;
3457 
3458         if (unlikely(ftrace_disabled))
3459                 return -ENODEV;
3460 
3461         mutex_lock(&ops->regex_lock);
3462 
3463         if (enable)
3464                 orig_hash = &ops->filter_hash;
3465         else
3466                 orig_hash = &ops->notrace_hash;
3467 
3468         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3469         if (!hash) {
3470                 ret = -ENOMEM;
3471                 goto out_regex_unlock;
3472         }
3473 
3474         if (reset)
3475                 ftrace_filter_reset(hash);
3476         if (buf && !ftrace_match_records(hash, buf, len)) {
3477                 ret = -EINVAL;
3478                 goto out_regex_unlock;
3479         }
3480         if (ip) {
3481                 ret = ftrace_match_addr(hash, ip, remove);
3482                 if (ret < 0)
3483                         goto out_regex_unlock;
3484         }
3485 
3486         mutex_lock(&ftrace_lock);
3487         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3488         if (!ret)
3489                 ftrace_ops_update_code(ops);
3490 
3491         mutex_unlock(&ftrace_lock);
3492 
3493  out_regex_unlock:
3494         mutex_unlock(&ops->regex_lock);
3495 
3496         free_ftrace_hash(hash);
3497         return ret;
3498 }
3499 
3500 static int
3501 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3502                 int reset, int enable)
3503 {
3504         return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3505 }
3506 
3507 /**
3508  * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3509  * @ops - the ops to set the filter with
3510  * @ip - the address to add to or remove from the filter.
3511  * @remove - non zero to remove the ip from the filter
3512  * @reset - non zero to reset all filters before applying this filter.
3513  *
3514  * Filters denote which functions should be enabled when tracing is enabled
3515  * If @ip is NULL, it failes to update filter.
3516  */
3517 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3518                          int remove, int reset)
3519 {
3520         ftrace_ops_init(ops);
3521         return ftrace_set_addr(ops, ip, remove, reset, 1);
3522 }
3523 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3524 
3525 static int
3526 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3527                  int reset, int enable)
3528 {
3529         return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3530 }
3531 
3532 /**
3533  * ftrace_set_filter - set a function to filter on in ftrace
3534  * @ops - the ops to set the filter with
3535  * @buf - the string that holds the function filter text.
3536  * @len - the length of the string.
3537  * @reset - non zero to reset all filters before applying this filter.
3538  *
3539  * Filters denote which functions should be enabled when tracing is enabled.
3540  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3541  */
3542 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3543                        int len, int reset)
3544 {
3545         ftrace_ops_init(ops);
3546         return ftrace_set_regex(ops, buf, len, reset, 1);
3547 }
3548 EXPORT_SYMBOL_GPL(ftrace_set_filter);
3549 
3550 /**
3551  * ftrace_set_notrace - set a function to not trace in ftrace
3552  * @ops - the ops to set the notrace filter with
3553  * @buf - the string that holds the function notrace text.
3554  * @len - the length of the string.
3555  * @reset - non zero to reset all filters before applying this filter.
3556  *
3557  * Notrace Filters denote which functions should not be enabled when tracing
3558  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3559  * for tracing.
3560  */
3561 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3562                         int len, int reset)
3563 {
3564         ftrace_ops_init(ops);
3565         return ftrace_set_regex(ops, buf, len, reset, 0);
3566 }
3567 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3568 /**
3569  * ftrace_set_filter - set a function to filter on in ftrace
3570  * @ops - the ops to set the filter with
3571  * @buf - the string that holds the function filter text.
3572  * @len - the length of the string.
3573  * @reset - non zero to reset all filters before applying this filter.
3574  *
3575  * Filters denote which functions should be enabled when tracing is enabled.
3576  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3577  */
3578 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3579 {
3580         ftrace_set_regex(&global_ops, buf, len, reset, 1);
3581 }
3582 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3583 
3584 /**
3585  * ftrace_set_notrace - set a function to not trace in ftrace
3586  * @ops - the ops to set the notrace filter with
3587  * @buf - the string that holds the function notrace text.
3588  * @len - the length of the string.
3589  * @reset - non zero to reset all filters before applying this filter.
3590  *
3591  * Notrace Filters denote which functions should not be enabled when tracing
3592  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3593  * for tracing.
3594  */
3595 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3596 {
3597         ftrace_set_regex(&global_ops, buf, len, reset, 0);
3598 }
3599 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3600 
3601 /*
3602  * command line interface to allow users to set filters on boot up.
3603  */
3604 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
3605 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3606 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3607 
3608 /* Used by function selftest to not test if filter is set */
3609 bool ftrace_filter_param __initdata;
3610 
3611 static int __init set_ftrace_notrace(char *str)
3612 {
3613         ftrace_filter_param = true;
3614         strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3615         return 1;
3616 }
3617 __setup("ftrace_notrace=", set_ftrace_notrace);
3618 
3619 static int __init set_ftrace_filter(char *str)
3620 {
3621         ftrace_filter_param = true;
3622         strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3623         return 1;
3624 }
3625 __setup("ftrace_filter=", set_ftrace_filter);
3626 
3627 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3628 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3629 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3630 
3631 static int __init set_graph_function(char *str)
3632 {
3633         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3634         return 1;
3635 }
3636 __setup("ftrace_graph_filter=", set_graph_function);
3637 
3638 static void __init set_ftrace_early_graph(char *buf)
3639 {
3640         int ret;
3641         char *func;
3642 
3643         while (buf) {
3644                 func = strsep(&buf, ",");
3645                 /* we allow only one expression at a time */
3646                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3647                                       func);
3648                 if (ret)
3649                         printk(KERN_DEBUG "ftrace: function %s not "
3650                                           "traceable\n", func);
3651         }
3652 }
3653 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3654 
3655 void __init
3656 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3657 {
3658         char *func;
3659 
3660         ftrace_ops_init(ops);
3661 
3662         while (buf) {
3663                 func = strsep(&buf, ",");
3664                 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3665         }
3666 }
3667 
3668 static void __init set_ftrace_early_filters(void)
3669 {
3670         if (ftrace_filter_buf[0])
3671                 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3672         if (ftrace_notrace_buf[0])
3673                 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3674 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3675         if (ftrace_graph_buf[0])
3676                 set_ftrace_early_graph(ftrace_graph_buf);
3677 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3678 }
3679 
3680 int ftrace_regex_release(struct inode *inode, struct file *file)
3681 {
3682         struct seq_file *m = (struct seq_file *)file->private_data;
3683         struct ftrace_iterator *iter;
3684         struct ftrace_hash **orig_hash;
3685         struct trace_parser *parser;
3686         int filter_hash;
3687         int ret;
3688 
3689         if (file->f_mode & FMODE_READ) {
3690                 iter = m->private;
3691                 seq_release(inode, file);
3692         } else
3693                 iter = file->private_data;
3694 
3695         parser = &iter->parser;
3696         if (trace_parser_loaded(parser)) {
3697                 parser->buffer[parser->idx] = 0;
3698                 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3699         }
3700 
3701         trace_parser_put(parser);
3702 
3703         mutex_lock(&iter->ops->regex_lock);
3704 
3705         if (file->f_mode & FMODE_WRITE) {
3706                 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3707 
3708                 if (filter_hash)
3709                         orig_hash = &iter->ops->filter_hash;
3710                 else
3711                         orig_hash = &iter->ops->notrace_hash;
3712 
3713                 mutex_lock(&ftrace_lock);
3714                 ret = ftrace_hash_move(iter->ops, filter_hash,
3715                                        orig_hash, iter->hash);
3716                 if (!ret)
3717                         ftrace_ops_update_code(iter->ops);
3718 
3719                 mutex_unlock(&ftrace_lock);
3720         }
3721 
3722         mutex_unlock(&iter->ops->regex_lock);
3723         free_ftrace_hash(iter->hash);
3724         kfree(iter);
3725 
3726         return 0;
3727 }
3728 
3729 static const struct file_operations ftrace_avail_fops = {
3730         .open = ftrace_avail_open,
3731         .read = seq_read,
3732         .llseek = seq_lseek,
3733         .release = seq_release_private,
3734 };
3735 
3736 static const struct file_operations ftrace_enabled_fops = {
3737         .open = ftrace_enabled_open,
3738         .read = seq_read,
3739         .llseek = seq_lseek,
3740         .release = seq_release_private,
3741 };
3742 
3743 static const struct file_operations ftrace_filter_fops = {
3744         .open = ftrace_filter_open,
3745         .read = seq_read,
3746         .write = ftrace_filter_write,
3747         .llseek = ftrace_filter_lseek,
3748         .release = ftrace_regex_release,
3749 };
3750 
3751 static const struct file_operations ftrace_notrace_fops = {
3752         .open = ftrace_notrace_open,
3753         .read = seq_read,
3754         .write = ftrace_notrace_write,
3755         .llseek = ftrace_filter_lseek,
3756         .release = ftrace_regex_release,
3757 };
3758 
3759 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3760 
3761 static DEFINE_MUTEX(graph_lock);
3762 
3763 int ftrace_graph_count;
3764 int ftrace_graph_filter_enabled;
3765 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3766 
3767 static void *
3768 __g_next(struct seq_file *m, loff_t *pos)
3769 {
3770         if (*pos >= ftrace_graph_count)
3771                 return NULL;
3772         return &ftrace_graph_funcs[*pos];
3773 }
3774 
3775 static void *
3776 g_next(struct seq_file *m, void *v, loff_t *pos)
3777 {
3778         (*pos)++;
3779         return __g_next(m, pos);
3780 }
3781 
3782 static void *g_start(struct seq_file *m, loff_t *pos)
3783 {
3784         mutex_lock(&graph_lock);
3785 
3786         /* Nothing, tell g_show to print all functions are enabled */
3787         if (!ftrace_graph_filter_enabled && !*pos)
3788                 return (void *)1;
3789 
3790         return __g_next(m, pos);
3791 }
3792 
3793 static void g_stop(struct seq_file *m, void *p)
3794 {
3795         mutex_unlock(&graph_lock);
3796 }
3797 
3798 static int g_show(struct seq_file *m, void *v)
3799 {
3800         unsigned long *ptr = v;
3801 
3802         if (!ptr)
3803                 return 0;
3804 
3805         if (ptr == (unsigned long *)1) {
3806                 seq_printf(m, "#### all functions enabled ####\n");
3807                 return 0;
3808         }
3809 
3810         seq_printf(m, "%ps\n", (void *)*ptr);
3811 
3812         return 0;
3813 }
3814 
3815 static const struct seq_operations ftrace_graph_seq_ops = {
3816         .start = g_start,
3817         .next = g_next,
3818         .stop = g_stop,
3819         .show = g_show,
3820 };
3821 
3822 static int
3823 ftrace_graph_open(struct inode *inode, struct file *file)
3824 {
3825         int ret = 0;
3826 
3827         if (unlikely(ftrace_disabled))
3828                 return -ENODEV;
3829 
3830         mutex_lock(&graph_lock);
3831         if ((file->f_mode & FMODE_WRITE) &&
3832             (file->f_flags & O_TRUNC)) {
3833                 ftrace_graph_filter_enabled = 0;
3834                 ftrace_graph_count = 0;
3835                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3836         }
3837         mutex_unlock(&graph_lock);
3838 
3839         if (file->f_mode & FMODE_READ)
3840                 ret = seq_open(file, &ftrace_graph_seq_ops);
3841 
3842         return ret;
3843 }
3844 
3845 static int
3846 ftrace_graph_release(struct inode *inode, struct file *file)
3847 {
3848         if (file->f_mode & FMODE_READ)
3849                 seq_release(inode, file);
3850         return 0;
3851 }
3852 
3853 static int
3854 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3855 {
3856         struct dyn_ftrace *rec;
3857         struct ftrace_page *pg;
3858         int search_len;
3859         int fail = 1;
3860         int type, not;
3861         char *search;
3862         bool exists;
3863         int i;
3864 
3865         /* decode regex */
3866         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
3867         if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3868                 return -EBUSY;
3869 
3870         search_len = strlen(search);
3871 
3872         mutex_lock(&ftrace_lock);
3873 
3874         if (unlikely(ftrace_disabled)) {
3875                 mutex_unlock(&ftrace_lock);
3876                 return -ENODEV;
3877         }
3878 
3879         do_for_each_ftrace_rec(pg, rec) {
3880 
3881                 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3882                         /* if it is in the array */
3883                         exists = false;
3884                         for (i = 0; i < *idx; i++) {
3885                                 if (array[i] == rec->ip) {
3886                                         exists = true;
3887                                         break;
3888                                 }
3889                         }
3890 
3891                         if (!not) {
3892                                 fail = 0;
3893                                 if (!exists) {
3894                                         array[(*idx)++] = rec->ip;
3895                                         if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3896                                                 goto out;
3897                                 }
3898                         } else {
3899                                 if (exists) {
3900                                         array[i] = array[--(*idx)];
3901                                         array[*idx] = 0;
3902                                         fail = 0;
3903                                 }
3904                         }
3905                 }
3906         } while_for_each_ftrace_rec();
3907 out:
3908         mutex_unlock(&ftrace_lock);
3909 
3910         if (fail)
3911                 return -EINVAL;
3912 
3913         ftrace_graph_filter_enabled = !!(*idx);
3914 
3915         return 0;
3916 }
3917 
3918 static ssize_t
3919 ftrace_graph_write(struct file *file, const char __user *ubuf,
3920                    size_t cnt, loff_t *ppos)
3921 {
3922         struct trace_parser parser;
3923         ssize_t read, ret;
3924 
3925         if (!cnt)
3926                 return 0;
3927 
3928         mutex_lock(&graph_lock);
3929 
3930         if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3931                 ret = -ENOMEM;
3932                 goto out_unlock;
3933         }
3934 
3935         read = trace_get_user(&parser, ubuf, cnt, ppos);
3936 
3937         if (read >= 0 && trace_parser_loaded((&parser))) {
3938                 parser.buffer[parser.idx] = 0;
3939 
3940                 /* we allow only one expression at a time */
3941                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3942                                         parser.buffer);
3943                 if (ret)
3944                         goto out_free;
3945         }
3946 
3947         ret = read;
3948 
3949 out_free:
3950         trace_parser_put(&parser);
3951 out_unlock:
3952         mutex_unlock(&graph_lock);
3953 
3954         return ret;
3955 }
3956 
3957 static const struct file_operations ftrace_graph_fops = {
3958         .open           = ftrace_graph_open,
3959         .read           = seq_read,
3960         .write          = ftrace_graph_write,
3961         .llseek         = ftrace_filter_lseek,
3962         .release        = ftrace_graph_release,
3963 };
3964 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3965 
3966 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3967 {
3968 
3969         trace_create_file("available_filter_functions", 0444,
3970                         d_tracer, NULL, &ftrace_avail_fops);
3971 
3972         trace_create_file("enabled_functions", 0444,
3973                         d_tracer, NULL, &ftrace_enabled_fops);
3974 
3975         trace_create_file("set_ftrace_filter", 0644, d_tracer,
3976                         NULL, &ftrace_filter_fops);
3977 
3978         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3979                                     NULL, &ftrace_notrace_fops);
3980 
3981 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3982         trace_create_file("set_graph_function", 0444, d_tracer,
3983                                     NULL,
3984                                     &ftrace_graph_fops);
3985 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3986 
3987         return 0;
3988 }
3989 
3990 static int ftrace_cmp_ips(const void *a, const void *b)
3991 {
3992         const unsigned long *ipa = a;
3993         const unsigned long *ipb = b;
3994 
3995         if (*ipa > *ipb)
3996                 return 1;
3997         if (*ipa < *ipb)
3998                 return -1;
3999         return 0;
4000 }
4001 
4002 static void ftrace_swap_ips(void *a, void *b, int size)
4003 {
4004         unsigned long *ipa = a;
4005         unsigned long *ipb = b;
4006         unsigned long t;
4007 
4008         t = *ipa;
4009         *ipa = *ipb;
4010         *ipb = t;
4011 }
4012 
4013 static int ftrace_process_locs(struct module *mod,
4014                                unsigned long *start,
4015                                unsigned long *end)
4016 {
4017         struct ftrace_page *start_pg;
4018         struct ftrace_page *pg;
4019         struct dyn_ftrace *rec;
4020         unsigned long count;
4021         unsigned long *p;
4022         unsigned long addr;
4023         unsigned long flags = 0; /* Shut up gcc */
4024         int ret = -ENOMEM;
4025 
4026         count = end - start;
4027 
4028         if (!count)
4029                 return 0;
4030 
4031         sort(start, count, sizeof(*start),
4032              ftrace_cmp_ips, ftrace_swap_ips);
4033 
4034         start_pg = ftrace_allocate_pages(count);
4035         if (!start_pg)
4036                 return -ENOMEM;
4037 
4038         mutex_lock(&ftrace_lock);
4039 
4040         /*
4041          * Core and each module needs their own pages, as
4042          * modules will free them when they are removed.
4043          * Force a new page to be allocated for modules.
4044          */
4045         if (!mod) {
4046                 WARN_ON(ftrace_pages || ftrace_pages_start);
4047                 /* First initialization */
4048                 ftrace_pages = ftrace_pages_start = start_pg;
4049         } else {
4050                 if (!ftrace_pages)
4051                         goto out;
4052 
4053                 if (WARN_ON(ftrace_pages->next)) {
4054                         /* Hmm, we have free pages? */
4055                         while (ftrace_pages->next)
4056                                 ftrace_pages = ftrace_pages->next;
4057                 }
4058 
4059                 ftrace_pages->next = start_pg;
4060         }
4061 
4062         p = start;
4063         pg = start_pg;
4064         while (p < end) {
4065                 addr = ftrace_call_adjust(*p++);
4066                 /*
4067                  * Some architecture linkers will pad between
4068                  * the different mcount_loc sections of different
4069                  * object files to satisfy alignments.
4070                  * Skip any NULL pointers.
4071                  */
4072                 if (!addr)
4073                         continue;
4074 
4075                 if (pg->index == pg->size) {
4076                         /* We should have allocated enough */
4077                         if (WARN_ON(!pg->next))
4078                                 break;
4079                         pg = pg->next;
4080                 }
4081 
4082                 rec = &pg->records[pg->index++];
4083                 rec->ip = addr;
4084         }
4085 
4086         /* We should have used all pages */
4087         WARN_ON(pg->next);
4088 
4089         /* Assign the last page to ftrace_pages */
4090         ftrace_pages = pg;
4091 
4092         /* These new locations need to be initialized */
4093         ftrace_new_pgs = start_pg;
4094 
4095         /*
4096          * We only need to disable interrupts on start up
4097          * because we are modifying code that an interrupt
4098          * may execute, and the modification is not atomic.
4099          * But for modules, nothing runs the code we modify
4100          * until we are finished with it, and there's no
4101          * reason to cause large interrupt latencies while we do it.
4102          */
4103         if (!mod)
4104                 local_irq_save(flags);
4105         ftrace_update_code(mod);
4106         if (!mod)
4107                 local_irq_restore(flags);
4108         ret = 0;
4109  out:
4110         mutex_unlock(&ftrace_lock);
4111 
4112         return ret;
4113 }
4114 
4115 #ifdef CONFIG_MODULES
4116 
4117 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4118 
4119 void ftrace_release_mod(struct module *mod)
4120 {
4121         struct dyn_ftrace *rec;
4122         struct ftrace_page **last_pg;
4123         struct ftrace_page *pg;
4124         int order;
4125 
4126         mutex_lock(&ftrace_lock);
4127 
4128         if (ftrace_disabled)
4129                 goto out_unlock;
4130 
4131         /*
4132          * Each module has its own ftrace_pages, remove
4133          * them from the list.
4134          */
4135         last_pg = &ftrace_pages_start;
4136         for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4137                 rec = &pg->records[0];
4138                 if (within_module_core(rec->ip, mod)) {
4139                         /*
4140                          * As core pages are first, the first
4141                          * page should never be a module page.
4142                          */
4143                         if (WARN_ON(pg == ftrace_pages_start))
4144                                 goto out_unlock;
4145 
4146                         /* Check if we are deleting the last page */
4147                         if (pg == ftrace_pages)
4148                                 ftrace_pages = next_to_ftrace_page(last_pg);
4149 
4150                         *last_pg = pg->next;
4151                         order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4152                         free_pages((unsigned long)pg->records, order);
4153                         kfree(pg);
4154                 } else
4155                         last_pg = &pg->next;
4156         }
4157  out_unlock:
4158         mutex_unlock(&ftrace_lock);
4159 }
4160 
4161 static void ftrace_init_module(struct module *mod,
4162                                unsigned long *start, unsigned long *end)
4163 {
4164         if (ftrace_disabled || start == end)
4165                 return;
4166         ftrace_process_locs(mod, start, end);
4167 }
4168 
4169 static int ftrace_module_notify_enter(struct notifier_block *self,
4170                                       unsigned long val, void *data)
4171 {
4172         struct module *mod = data;
4173 
4174         if (val == MODULE_STATE_COMING)
4175                 ftrace_init_module(mod, mod->ftrace_callsites,
4176                                    mod->ftrace_callsites +
4177                                    mod->num_ftrace_callsites);
4178         return 0;
4179 }
4180 
4181 static int ftrace_module_notify_exit(struct notifier_block *self,
4182                                      unsigned long val, void *data)
4183 {
4184         struct module *mod = data;
4185 
4186         if (val == MODULE_STATE_GOING)
4187                 ftrace_release_mod(mod);
4188 
4189         return 0;
4190 }
4191 #else
4192 static int ftrace_module_notify_enter(struct notifier_block *self,
4193                                       unsigned long val, void *data)
4194 {
4195         return 0;
4196 }
4197 static int ftrace_module_notify_exit(struct notifier_block *self,
4198                                      unsigned long val, void *data)
4199 {
4200         return 0;
4201 }
4202 #endif /* CONFIG_MODULES */
4203 
4204 struct notifier_block ftrace_module_enter_nb = {
4205         .notifier_call = ftrace_module_notify_enter,
4206         .priority = INT_MAX,    /* Run before anything that can use kprobes */
4207 };
4208 
4209 struct notifier_block ftrace_module_exit_nb = {
4210         .notifier_call = ftrace_module_notify_exit,
4211         .priority = INT_MIN,    /* Run after anything that can remove kprobes */
4212 };
4213 
4214 extern unsigned long __start_mcount_loc[];
4215 extern unsigned long __stop_mcount_loc[];
4216 
4217 void __init ftrace_init(void)
4218 {
4219         unsigned long count, addr, flags;
4220         int ret;
4221 
4222         /* Keep the ftrace pointer to the stub */
4223         addr = (unsigned long)ftrace_stub;
4224 
4225         local_irq_save(flags);
4226         ftrace_dyn_arch_init(&addr);
4227         local_irq_restore(flags);
4228 
4229         /* ftrace_dyn_arch_init places the return code in addr */
4230         if (addr)
4231                 goto failed;
4232 
4233         count = __stop_mcount_loc - __start_mcount_loc;
4234 
4235         ret = ftrace_dyn_table_alloc(count);
4236         if (ret)
4237                 goto failed;
4238 
4239         last_ftrace_enabled = ftrace_enabled = 1;
4240 
4241         ret = ftrace_process_locs(NULL,
4242                                   __start_mcount_loc,
4243                                   __stop_mcount_loc);
4244 
4245         ret = register_module_notifier(&ftrace_module_enter_nb);
4246         if (ret)
4247                 pr_warning("Failed to register trace ftrace module enter notifier\n");
4248 
4249         ret = register_module_notifier(&ftrace_module_exit_nb);
4250         if (ret)
4251                 pr_warning("Failed to register trace ftrace module exit notifier\n");
4252 
4253         set_ftrace_early_filters();
4254 
4255         return;
4256  failed:
4257         ftrace_disabled = 1;
4258 }
4259 
4260 #else
4261 
4262 static struct ftrace_ops global_ops = {
4263         .func                   = ftrace_stub,
4264         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4265         INIT_REGEX_LOCK(global_ops)
4266 };
4267 
4268 static int __init ftrace_nodyn_init(void)
4269 {
4270         ftrace_enabled = 1;
4271         return 0;
4272 }
4273 core_initcall(ftrace_nodyn_init);
4274 
4275 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4276 static inline void ftrace_startup_enable(int command) { }
4277 /* Keep as macros so we do not need to define the commands */
4278 # define ftrace_startup(ops, command)                   \
4279         ({                                              \
4280                 (ops)->flags |= FTRACE_OPS_FL_ENABLED;  \
4281                 0;                                      \
4282         })
4283 # define ftrace_shutdown(ops, command)  do { } while (0)
4284 # define ftrace_startup_sysctl()        do { } while (0)
4285 # define ftrace_shutdown_sysctl()       do { } while (0)
4286 
4287 static inline int
4288 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4289 {
4290         return 1;
4291 }
4292 
4293 #endif /* CONFIG_DYNAMIC_FTRACE */
4294 
4295 static void
4296 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4297                         struct ftrace_ops *op, struct pt_regs *regs)
4298 {
4299         if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4300                 return;
4301 
4302         /*
4303          * Some of the ops may be dynamically allocated,
4304          * they must be freed after a synchronize_sched().
4305          */
4306         preempt_disable_notrace();
4307         trace_recursion_set(TRACE_CONTROL_BIT);
4308         do_for_each_ftrace_op(op, ftrace_control_list) {
4309                 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4310                     !ftrace_function_local_disabled(op) &&
4311                     ftrace_ops_test(op, ip, regs))
4312                         op->func(ip, parent_ip, op, regs);
4313         } while_for_each_ftrace_op(op);
4314         trace_recursion_clear(TRACE_CONTROL_BIT);
4315         preempt_enable_notrace();
4316 }
4317 
4318 static struct ftrace_ops control_ops = {
4319         .func   = ftrace_ops_control_func,
4320         .flags  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4321         INIT_REGEX_LOCK(control_ops)
4322 };
4323 
4324 static inline void
4325 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4326                        struct ftrace_ops *ignored, struct pt_regs *regs)
4327 {
4328         struct ftrace_ops *op;
4329         int bit;
4330 
4331         if (function_trace_stop)
4332                 return;
4333 
4334         bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4335         if (bit < 0)
4336                 return;
4337 
4338         /*
4339          * Some of the ops may be dynamically allocated,
4340          * they must be freed after a synchronize_sched().
4341          */
4342         preempt_disable_notrace();
4343         do_for_each_ftrace_op(op, ftrace_ops_list) {
4344                 if (ftrace_ops_test(op, ip, regs))
4345                         op->func(ip, parent_ip, op, regs);
4346         } while_for_each_ftrace_op(op);
4347         preempt_enable_notrace();
4348         trace_clear_recursion(bit);
4349 }
4350 
4351 /*
4352  * Some archs only support passing ip and parent_ip. Even though
4353  * the list function ignores the op parameter, we do not want any
4354  * C side effects, where a function is called without the caller
4355  * sending a third parameter.
4356  * Archs are to support both the regs and ftrace_ops at the same time.
4357  * If they support ftrace_ops, it is assumed they support regs.
4358  * If call backs want to use regs, they must either check for regs
4359  * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4360  * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4361  * An architecture can pass partial regs with ftrace_ops and still
4362  * set the ARCH_SUPPORT_FTARCE_OPS.
4363  */
4364 #if ARCH_SUPPORTS_FTRACE_OPS
4365 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4366                                  struct ftrace_ops *op, struct pt_regs *regs)
4367 {
4368         __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4369 }
4370 #else
4371 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4372 {
4373         __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4374 }
4375 #endif
4376 
4377 static void clear_ftrace_swapper(void)
4378 {
4379         struct task_struct *p;
4380         int cpu;
4381 
4382         get_online_cpus();
4383         for_each_online_cpu(cpu) {
4384                 p = idle_task(cpu);
4385                 clear_tsk_trace_trace(p);
4386         }
4387         put_online_cpus();
4388 }
4389 
4390 static void set_ftrace_swapper(void)
4391 {
4392         struct task_struct *p;
4393         int cpu;
4394 
4395         get_online_cpus();
4396         for_each_online_cpu(cpu) {
4397                 p = idle_task(cpu);
4398                 set_tsk_trace_trace(p);
4399         }
4400         put_online_cpus();
4401 }
4402 
4403 static void clear_ftrace_pid(struct pid *pid)
4404 {
4405         struct task_struct *p;
4406 
4407         rcu_read_lock();
4408         do_each_pid_task(pid, PIDTYPE_PID, p) {
4409                 clear_tsk_trace_trace(p);
4410         } while_each_pid_task(pid, PIDTYPE_PID, p);
4411         rcu_read_unlock();
4412 
4413         put_pid(pid);
4414 }
4415 
4416 static void set_ftrace_pid(struct pid *pid)
4417 {
4418         struct task_struct *p;
4419 
4420         rcu_read_lock();
4421         do_each_pid_task(pid, PIDTYPE_PID, p) {
4422                 set_tsk_trace_trace(p);
4423         } while_each_pid_task(pid, PIDTYPE_PID, p);
4424         rcu_read_unlock();
4425 }
4426 
4427 static void clear_ftrace_pid_task(struct pid *pid)
4428 {
4429         if (pid == ftrace_swapper_pid)
4430                 clear_ftrace_swapper();
4431         else
4432                 clear_ftrace_pid(pid);
4433 }
4434 
4435 static void set_ftrace_pid_task(struct pid *pid)
4436 {
4437         if (pid == ftrace_swapper_pid)
4438                 set_ftrace_swapper();
4439         else
4440                 set_ftrace_pid(pid);
4441 }
4442 
4443 static int ftrace_pid_add(int p)
4444 {
4445         struct pid *pid;
4446         struct ftrace_pid *fpid;
4447         int ret = -EINVAL;
4448 
4449         mutex_lock(&ftrace_lock);
4450 
4451         if (!p)
4452                 pid = ftrace_swapper_pid;
4453         else
4454                 pid = find_get_pid(p);
4455 
4456         if (!pid)
4457                 goto out;
4458 
4459         ret = 0;
4460 
4461         list_for_each_entry(fpid, &ftrace_pids, list)
4462                 if (fpid->pid == pid)
4463                         goto out_put;
4464 
4465         ret = -ENOMEM;
4466 
4467         fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4468         if (!fpid)
4469                 goto out_put;
4470 
4471         list_add(&fpid->list, &ftrace_pids);
4472         fpid->pid = pid;
4473 
4474         set_ftrace_pid_task(pid);
4475 
4476         ftrace_update_pid_func();
4477         ftrace_startup_enable(0);
4478 
4479         mutex_unlock(&ftrace_lock);
4480         return 0;
4481 
4482 out_put:
4483         if (pid != ftrace_swapper_pid)
4484                 put_pid(pid);
4485 
4486 out:
4487         mutex_unlock(&ftrace_lock);
4488         return ret;
4489 }
4490 
4491 static void ftrace_pid_reset(void)
4492 {
4493         struct ftrace_pid *fpid, *safe;
4494 
4495         mutex_lock(&ftrace_lock);
4496         list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4497                 struct pid *pid = fpid->pid;
4498 
4499                 clear_ftrace_pid_task(pid);
4500 
4501                 list_del(&fpid->list);
4502                 kfree(fpid);
4503         }
4504 
4505         ftrace_update_pid_func();
4506         ftrace_startup_enable(0);
4507 
4508         mutex_unlock(&ftrace_lock);
4509 }
4510 
4511 static void *fpid_start(struct seq_file *m, loff_t *pos)
4512 {
4513         mutex_lock(&ftrace_lock);
4514 
4515         if (list_empty(&ftrace_pids) && (!*pos))
4516                 return (void *) 1;
4517 
4518         return seq_list_start(&ftrace_pids, *pos);
4519 }
4520 
4521 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4522 {
4523         if (v == (void *)1)
4524                 return NULL;
4525 
4526         return seq_list_next(v, &ftrace_pids, pos);
4527 }
4528 
4529 static void fpid_stop(struct seq_file *m, void *p)
4530 {
4531         mutex_unlock(&ftrace_lock);
4532 }
4533 
4534 static int fpid_show(struct seq_file *m, void *v)
4535 {
4536         const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4537 
4538         if (v == (void *)1) {
4539                 seq_printf(m, "no pid\n");
4540                 return 0;
4541         }
4542 
4543         if (fpid->pid == ftrace_swapper_pid)
4544                 seq_printf(m, "swapper tasks\n");
4545         else
4546                 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4547 
4548         return 0;
4549 }
4550 
4551 static const struct seq_operations ftrace_pid_sops = {
4552         .start = fpid_start,
4553         .next = fpid_next,
4554         .stop = fpid_stop,
4555         .show = fpid_show,
4556 };
4557 
4558 static int
4559 ftrace_pid_open(struct inode *inode, struct file *file)
4560 {
4561         int ret = 0;
4562 
4563         if ((file->f_mode & FMODE_WRITE) &&
4564             (file->f_flags & O_TRUNC))
4565                 ftrace_pid_reset();
4566 
4567         if (file->f_mode & FMODE_READ)
4568                 ret = seq_open(file, &ftrace_pid_sops);
4569 
4570         return ret;
4571 }
4572 
4573 static ssize_t
4574 ftrace_pid_write(struct file *filp, const char __user *ubuf,
4575                    size_t cnt, loff_t *ppos)
4576 {
4577         char buf[64], *tmp;
4578         long val;
4579         int ret;
4580 
4581         if (cnt >= sizeof(buf))
4582                 return -EINVAL;
4583 
4584         if (copy_from_user(&buf, ubuf, cnt))
4585                 return -EFAULT;
4586 
4587         buf[cnt] = 0;
4588 
4589         /*
4590          * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4591          * to clean the filter quietly.
4592          */
4593         tmp = strstrip(buf);
4594         if (strlen(tmp) == 0)
4595                 return 1;
4596 
4597         ret = kstrtol(tmp, 10, &val);
4598         if (ret < 0)
4599                 return ret;
4600 
4601         ret = ftrace_pid_add(val);
4602 
4603         return ret ? ret : cnt;
4604 }
4605 
4606 static int
4607 ftrace_pid_release(struct inode *inode, struct file *file)
4608 {
4609         if (file->f_mode & FMODE_READ)
4610                 seq_release(inode, file);
4611 
4612         return 0;
4613 }
4614 
4615 static const struct file_operations ftrace_pid_fops = {
4616         .open           = ftrace_pid_open,
4617         .write          = ftrace_pid_write,
4618         .read           = seq_read,
4619         .llseek         = ftrace_filter_lseek,
4620         .release        = ftrace_pid_release,
4621 };
4622 
4623 static __init int ftrace_init_debugfs(void)
4624 {
4625         struct dentry *d_tracer;
4626 
4627         d_tracer = tracing_init_dentry();
4628         if (!d_tracer)
4629                 return 0;
4630 
4631         ftrace_init_dyn_debugfs(d_tracer);
4632 
4633         trace_create_file("set_ftrace_pid", 0644, d_tracer,
4634                             NULL, &ftrace_pid_fops);
4635 
4636         ftrace_profile_debugfs(d_tracer);
4637 
4638         return 0;
4639 }
4640 fs_initcall(ftrace_init_debugfs);
4641 
4642 /**
4643  * ftrace_kill - kill ftrace
4644  *
4645  * This function should be used by panic code. It stops ftrace
4646  * but in a not so nice way. If you need to simply kill ftrace
4647  * from a non-atomic section, use ftrace_kill.
4648  */
4649 void ftrace_kill(void)
4650 {
4651         ftrace_disabled = 1;
4652         ftrace_enabled = 0;
4653         clear_ftrace_function();
4654 }
4655 
4656 /**
4657  * Test if ftrace is dead or not.
4658  */
4659 int ftrace_is_dead(void)
4660 {
4661         return ftrace_disabled;
4662 }
4663 
4664 /**
4665  * register_ftrace_function - register a function for profiling
4666  * @ops - ops structure that holds the function for profiling.
4667  *
4668  * Register a function to be called by all functions in the
4669  * kernel.
4670  *
4671  * Note: @ops->func and all the functions it calls must be labeled
4672  *       with "notrace", otherwise it will go into a
4673  *       recursive loop.
4674  */
4675 int register_ftrace_function(struct ftrace_ops *ops)
4676 {
4677         int ret = -1;
4678 
4679         ftrace_ops_init(ops);
4680 
4681         mutex_lock(&ftrace_lock);
4682 
4683         ret = __register_ftrace_function(ops);
4684         if (!ret)
4685                 ret = ftrace_startup(ops, 0);
4686 
4687         mutex_unlock(&ftrace_lock);
4688 
4689         return ret;
4690 }
4691 EXPORT_SYMBOL_GPL(register_ftrace_function);
4692 
4693 /**
4694  * unregister_ftrace_function - unregister a function for profiling.
4695  * @ops - ops structure that holds the function to unregister
4696  *
4697  * Unregister a function that was added to be called by ftrace profiling.
4698  */
4699 int unregister_ftrace_function(struct ftrace_ops *ops)
4700 {
4701         int ret;
4702 
4703         mutex_lock(&ftrace_lock);
4704         ret = __unregister_ftrace_function(ops);
4705         if (!ret)
4706                 ftrace_shutdown(ops, 0);
4707         mutex_unlock(&ftrace_lock);
4708 
4709         return ret;
4710 }
4711 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4712 
4713 int
4714 ftrace_enable_sysctl(struct ctl_table *table, int write,
4715                      void __user *buffer, size_t *lenp,
4716                      loff_t *ppos)
4717 {
4718         int ret = -ENODEV;
4719 
4720         mutex_lock(&ftrace_lock);
4721 
4722         if (unlikely(ftrace_disabled))
4723                 goto out;
4724 
4725         ret = proc_dointvec(table, write, buffer, lenp, ppos);
4726 
4727         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4728                 goto out;
4729 
4730         last_ftrace_enabled = !!ftrace_enabled;
4731 
4732         if (ftrace_enabled) {
4733 
4734                 ftrace_startup_sysctl();
4735 
4736                 /* we are starting ftrace again */
4737                 if (ftrace_ops_list != &ftrace_list_end)
4738                         update_ftrace_function();
4739 
4740         } else {
4741                 /* stopping ftrace calls (just send to ftrace_stub) */
4742                 ftrace_trace_function = ftrace_stub;
4743 
4744                 ftrace_shutdown_sysctl();
4745         }
4746 
4747  out:
4748         mutex_unlock(&ftrace_lock);
4749         return ret;
4750 }
4751 
4752 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
4753 
4754 static int ftrace_graph_active;
4755 static struct notifier_block ftrace_suspend_notifier;
4756 
4757 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4758 {
4759         return 0;
4760 }
4761 
4762 /* The callbacks that hook a function */
4763 trace_func_graph_ret_t ftrace_graph_return =
4764                         (trace_func_graph_ret_t)ftrace_stub;
4765 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4766 
4767 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4768 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4769 {
4770         int i;
4771         int ret = 0;
4772         unsigned long flags;
4773         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4774         struct task_struct *g, *t;
4775 
4776         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4777                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4778                                         * sizeof(struct ftrace_ret_stack),
4779                                         GFP_KERNEL);
4780                 if (!ret_stack_list[i]) {
4781                         start = 0;
4782                         end = i;
4783                         ret = -ENOMEM;
4784                         goto free;
4785                 }
4786         }
4787 
4788         read_lock_irqsave(&tasklist_lock, flags);
4789         do_each_thread(g, t) {
4790                 if (start == end) {
4791                         ret = -EAGAIN;
4792                         goto unlock;
4793                 }
4794 
4795                 if (t->ret_stack == NULL) {
4796                         atomic_set(&t->tracing_graph_pause, 0);
4797                         atomic_set(&t->trace_overrun, 0);
4798                         t->curr_ret_stack = -1;
4799                         /* Make sure the tasks see the -1 first: */
4800                         smp_wmb();
4801                         t->ret_stack = ret_stack_list[start++];
4802                 }
4803         } while_each_thread(g, t);
4804 
4805 unlock:
4806         read_unlock_irqrestore(&tasklist_lock, flags);
4807 free:
4808         for (i = start; i < end; i++)
4809                 kfree(ret_stack_list[i]);
4810         return ret;
4811 }
4812 
4813 static void
4814 ftrace_graph_probe_sched_switch(void *ignore,
4815                         struct task_struct *prev, struct task_struct *next)
4816 {
4817         unsigned long long timestamp;
4818         int index;
4819 
4820         /*
4821          * Does the user want to count the time a function was asleep.
4822          * If so, do not update the time stamps.
4823          */
4824         if (trace_flags & TRACE_ITER_SLEEP_TIME)
4825                 return;
4826 
4827         timestamp = trace_clock_local();
4828 
4829         prev->ftrace_timestamp = timestamp;
4830 
4831         /* only process tasks that we timestamped */
4832         if (!next->ftrace_timestamp)
4833                 return;
4834 
4835         /*
4836          * Update all the counters in next to make up for the
4837          * time next was sleeping.
4838          */
4839         timestamp -= next->ftrace_timestamp;
4840 
4841         for (index = next->curr_ret_stack; index >= 0; index--)
4842                 next->ret_stack[index].calltime += timestamp;
4843 }
4844 
4845 /* Allocate a return stack for each task */
4846 static int start_graph_tracing(void)
4847 {
4848         struct ftrace_ret_stack **ret_stack_list;
4849         int ret, cpu;
4850 
4851         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4852                                 sizeof(struct ftrace_ret_stack *),
4853                                 GFP_KERNEL);
4854 
4855         if (!ret_stack_list)
4856                 return -ENOMEM;
4857 
4858         /* The cpu_boot init_task->ret_stack will never be freed */
4859         for_each_online_cpu(cpu) {
4860                 if (!idle_task(cpu)->ret_stack)
4861                         ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4862         }
4863 
4864         do {
4865                 ret = alloc_retstack_tasklist(ret_stack_list);
4866         } while (ret == -EAGAIN);
4867 
4868         if (!ret) {
4869                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4870                 if (ret)
4871                         pr_info("ftrace_graph: Couldn't activate tracepoint"
4872                                 " probe to kernel_sched_switch\n");
4873         }
4874 
4875         kfree(ret_stack_list);
4876         return ret;
4877 }
4878 
4879 /*
4880  * Hibernation protection.
4881  * The state of the current task is too much unstable during
4882  * suspend/restore to disk. We want to protect against that.
4883  */
4884 static int
4885 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4886                                                         void *unused)
4887 {
4888         switch (state) {
4889         case PM_HIBERNATION_PREPARE:
4890                 pause_graph_tracing();
4891                 break;
4892 
4893         case PM_POST_HIBERNATION:
4894                 unpause_graph_tracing();
4895                 break;
4896         }
4897         return NOTIFY_DONE;
4898 }
4899 
4900 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4901                         trace_func_graph_ent_t entryfunc)
4902 {
4903         int ret = 0;
4904 
4905         mutex_lock(&ftrace_lock);
4906 
4907         /* we currently allow only one tracer registered at a time */
4908         if (ftrace_graph_active) {
4909                 ret = -EBUSY;
4910                 goto out;
4911         }
4912 
4913         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4914         register_pm_notifier(&ftrace_suspend_notifier);
4915 
4916         ftrace_graph_active++;
4917         ret = start_graph_tracing();
4918         if (ret) {
4919                 ftrace_graph_active--;
4920                 goto out;
4921         }
4922 
4923         ftrace_graph_return = retfunc;
4924         ftrace_graph_entry = entryfunc;
4925 
4926         ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4927 
4928 out:
4929         mutex_unlock(&ftrace_lock);
4930         return ret;
4931 }
4932 
4933 void unregister_ftrace_graph(void)
4934 {
4935         mutex_lock(&ftrace_lock);
4936 
4937         if (unlikely(!ftrace_graph_active))
4938                 goto out;
4939 
4940         ftrace_graph_active--;
4941         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4942         ftrace_graph_entry = ftrace_graph_entry_stub;
4943         ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4944         unregister_pm_notifier(&ftrace_suspend_notifier);
4945         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4946 
4947  out:
4948         mutex_unlock(&ftrace_lock);
4949 }
4950 
4951 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4952 
4953 static void
4954 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4955 {
4956         atomic_set(&t->tracing_graph_pause, 0);
4957         atomic_set(&t->trace_overrun, 0);
4958         t->ftrace_timestamp = 0;
4959         /* make curr_ret_stack visible before we add the ret_stack */
4960         smp_wmb();
4961         t->ret_stack = ret_stack;
4962 }
4963 
4964 /*
4965  * Allocate a return stack for the idle task. May be the first
4966  * time through, or it may be done by CPU hotplug online.
4967  */
4968 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4969 {
4970         t->curr_ret_stack = -1;
4971         /*
4972          * The idle task has no parent, it either has its own
4973          * stack or no stack at all.
4974          */
4975         if (t->ret_stack)
4976                 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4977 
4978         if (ftrace_graph_active) {
4979                 struct ftrace_ret_stack *ret_stack;
4980 
4981                 ret_stack = per_cpu(idle_ret_stack, cpu);
4982                 if (!ret_stack) {
4983                         ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4984                                             * sizeof(struct ftrace_ret_stack),
4985                                             GFP_KERNEL);
4986                         if (!ret_stack)
4987                                 return;
4988                         per_cpu(idle_ret_stack, cpu) = ret_stack;
4989                 }
4990                 graph_init_task(t, ret_stack);
4991         }
4992 }
4993 
4994 /* Allocate a return stack for newly created task */
4995 void ftrace_graph_init_task(struct task_struct *t)
4996 {
4997         /* Make sure we do not use the parent ret_stack */
4998         t->ret_stack = NULL;
4999         t->curr_ret_stack = -1;
5000 
5001         if (ftrace_graph_active) {
5002                 struct ftrace_ret_stack *ret_stack;
5003 
5004                 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5005                                 * sizeof(struct ftrace_ret_stack),
5006                                 GFP_KERNEL);
5007                 if (!ret_stack)
5008                         return;
5009                 graph_init_task(t, ret_stack);
5010         }
5011 }
5012 
5013 void ftrace_graph_exit_task(struct task_struct *t)
5014 {
5015         struct ftrace_ret_stack *ret_stack = t->ret_stack;
5016 
5017         t->ret_stack = NULL;
5018         /* NULL must become visible to IRQs before we free it: */
5019         barrier();
5020 
5021         kfree(ret_stack);
5022 }
5023 
5024 void ftrace_graph_stop(void)
5025 {
5026         ftrace_stop();
5027 }
5028 #endif
5029 

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