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TOMOYO Linux Cross Reference
Linux/include/linux/ftrace.h

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 /*
  3  * Ftrace header.  For implementation details beyond the random comments
  4  * scattered below, see: Documentation/trace/ftrace-design.rst
  5  */
  6 
  7 #ifndef _LINUX_FTRACE_H
  8 #define _LINUX_FTRACE_H
  9 
 10 #include <linux/trace_recursion.h>
 11 #include <linux/trace_clock.h>
 12 #include <linux/kallsyms.h>
 13 #include <linux/linkage.h>
 14 #include <linux/bitops.h>
 15 #include <linux/ptrace.h>
 16 #include <linux/ktime.h>
 17 #include <linux/sched.h>
 18 #include <linux/types.h>
 19 #include <linux/init.h>
 20 #include <linux/fs.h>
 21 
 22 #include <asm/ftrace.h>
 23 
 24 /*
 25  * If the arch supports passing the variable contents of
 26  * function_trace_op as the third parameter back from the
 27  * mcount call, then the arch should define this as 1.
 28  */
 29 #ifndef ARCH_SUPPORTS_FTRACE_OPS
 30 #define ARCH_SUPPORTS_FTRACE_OPS 0
 31 #endif
 32 
 33 /*
 34  * If the arch's mcount caller does not support all of ftrace's
 35  * features, then it must call an indirect function that
 36  * does. Or at least does enough to prevent any unwelcome side effects.
 37  */
 38 #if !ARCH_SUPPORTS_FTRACE_OPS
 39 # define FTRACE_FORCE_LIST_FUNC 1
 40 #else
 41 # define FTRACE_FORCE_LIST_FUNC 0
 42 #endif
 43 
 44 /* Main tracing buffer and events set up */
 45 #ifdef CONFIG_TRACING
 46 void trace_init(void);
 47 void early_trace_init(void);
 48 #else
 49 static inline void trace_init(void) { }
 50 static inline void early_trace_init(void) { }
 51 #endif
 52 
 53 struct module;
 54 struct ftrace_hash;
 55 struct ftrace_direct_func;
 56 
 57 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
 58         defined(CONFIG_DYNAMIC_FTRACE)
 59 const char *
 60 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
 61                    unsigned long *off, char **modname, char *sym);
 62 #else
 63 static inline const char *
 64 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
 65                    unsigned long *off, char **modname, char *sym)
 66 {
 67         return NULL;
 68 }
 69 #endif
 70 
 71 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
 72 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
 73                            char *type, char *name,
 74                            char *module_name, int *exported);
 75 #else
 76 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
 77                                          char *type, char *name,
 78                                          char *module_name, int *exported)
 79 {
 80         return -1;
 81 }
 82 #endif
 83 
 84 #ifdef CONFIG_FUNCTION_TRACER
 85 
 86 extern int ftrace_enabled;
 87 extern int
 88 ftrace_enable_sysctl(struct ctl_table *table, int write,
 89                      void *buffer, size_t *lenp, loff_t *ppos);
 90 
 91 struct ftrace_ops;
 92 
 93 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
 94 
 95 struct ftrace_regs {
 96         struct pt_regs          regs;
 97 };
 98 #define arch_ftrace_get_regs(fregs) (&(fregs)->regs)
 99 
100 /*
101  * ftrace_instruction_pointer_set() is to be defined by the architecture
102  * if to allow setting of the instruction pointer from the ftrace_regs
103  * when HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports
104  * live kernel patching.
105  */
106 #define ftrace_instruction_pointer_set(fregs, ip) do { } while (0)
107 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
108 
109 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
110 {
111         if (!fregs)
112                 return NULL;
113 
114         return arch_ftrace_get_regs(fregs);
115 }
116 
117 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
118                               struct ftrace_ops *op, struct ftrace_regs *fregs);
119 
120 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
121 
122 /*
123  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
124  * set in the flags member.
125  * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
126  * IPMODIFY are a kind of attribute flags which can be set only before
127  * registering the ftrace_ops, and can not be modified while registered.
128  * Changing those attribute flags after registering ftrace_ops will
129  * cause unexpected results.
130  *
131  * ENABLED - set/unset when ftrace_ops is registered/unregistered
132  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
133  *           allocated ftrace_ops which need special care
134  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
135  *            and passed to the callback. If this flag is set, but the
136  *            architecture does not support passing regs
137  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
138  *            ftrace_ops will fail to register, unless the next flag
139  *            is set.
140  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
141  *            handler can handle an arch that does not save regs
142  *            (the handler tests if regs == NULL), then it can set
143  *            this flag instead. It will not fail registering the ftrace_ops
144  *            but, the regs field will be NULL if the arch does not support
145  *            passing regs to the handler.
146  *            Note, if this flag is set, the SAVE_REGS flag will automatically
147  *            get set upon registering the ftrace_ops, if the arch supports it.
148  * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
149  *            that the call back needs recursion protection. If it does
150  *            not set this, then the ftrace infrastructure will assume
151  *            that the callback can handle recursion on its own.
152  * STUB   - The ftrace_ops is just a place holder.
153  * INITIALIZED - The ftrace_ops has already been initialized (first use time
154  *            register_ftrace_function() is called, it will initialized the ops)
155  * DELETED - The ops are being deleted, do not let them be registered again.
156  * ADDING  - The ops is in the process of being added.
157  * REMOVING - The ops is in the process of being removed.
158  * MODIFYING - The ops is in the process of changing its filter functions.
159  * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
160  *            The arch specific code sets this flag when it allocated a
161  *            trampoline. This lets the arch know that it can update the
162  *            trampoline in case the callback function changes.
163  *            The ftrace_ops trampoline can be set by the ftrace users, and
164  *            in such cases the arch must not modify it. Only the arch ftrace
165  *            core code should set this flag.
166  * IPMODIFY - The ops can modify the IP register. This can only be set with
167  *            SAVE_REGS. If another ops with this flag set is already registered
168  *            for any of the functions that this ops will be registered for, then
169  *            this ops will fail to register or set_filter_ip.
170  * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
171  * RCU     - Set when the ops can only be called when RCU is watching.
172  * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
173  * PERMANENT - Set when the ops is permanent and should not be affected by
174  *             ftrace_enabled.
175  * DIRECT - Used by the direct ftrace_ops helper for direct functions
176  *            (internal ftrace only, should not be used by others)
177  */
178 enum {
179         FTRACE_OPS_FL_ENABLED                   = BIT(0),
180         FTRACE_OPS_FL_DYNAMIC                   = BIT(1),
181         FTRACE_OPS_FL_SAVE_REGS                 = BIT(2),
182         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = BIT(3),
183         FTRACE_OPS_FL_RECURSION                 = BIT(4),
184         FTRACE_OPS_FL_STUB                      = BIT(5),
185         FTRACE_OPS_FL_INITIALIZED               = BIT(6),
186         FTRACE_OPS_FL_DELETED                   = BIT(7),
187         FTRACE_OPS_FL_ADDING                    = BIT(8),
188         FTRACE_OPS_FL_REMOVING                  = BIT(9),
189         FTRACE_OPS_FL_MODIFYING                 = BIT(10),
190         FTRACE_OPS_FL_ALLOC_TRAMP               = BIT(11),
191         FTRACE_OPS_FL_IPMODIFY                  = BIT(12),
192         FTRACE_OPS_FL_PID                       = BIT(13),
193         FTRACE_OPS_FL_RCU                       = BIT(14),
194         FTRACE_OPS_FL_TRACE_ARRAY               = BIT(15),
195         FTRACE_OPS_FL_PERMANENT                 = BIT(16),
196         FTRACE_OPS_FL_DIRECT                    = BIT(17),
197 };
198 
199 #ifdef CONFIG_DYNAMIC_FTRACE
200 /* The hash used to know what functions callbacks trace */
201 struct ftrace_ops_hash {
202         struct ftrace_hash __rcu        *notrace_hash;
203         struct ftrace_hash __rcu        *filter_hash;
204         struct mutex                    regex_lock;
205 };
206 
207 void ftrace_free_init_mem(void);
208 void ftrace_free_mem(struct module *mod, void *start, void *end);
209 #else
210 static inline void ftrace_free_init_mem(void) { }
211 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
212 #endif
213 
214 /*
215  * Note, ftrace_ops can be referenced outside of RCU protection, unless
216  * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
217  * core data, the unregistering of it will perform a scheduling on all CPUs
218  * to make sure that there are no more users. Depending on the load of the
219  * system that may take a bit of time.
220  *
221  * Any private data added must also take care not to be freed and if private
222  * data is added to a ftrace_ops that is in core code, the user of the
223  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
224  */
225 struct ftrace_ops {
226         ftrace_func_t                   func;
227         struct ftrace_ops __rcu         *next;
228         unsigned long                   flags;
229         void                            *private;
230         ftrace_func_t                   saved_func;
231 #ifdef CONFIG_DYNAMIC_FTRACE
232         struct ftrace_ops_hash          local_hash;
233         struct ftrace_ops_hash          *func_hash;
234         struct ftrace_ops_hash          old_hash;
235         unsigned long                   trampoline;
236         unsigned long                   trampoline_size;
237         struct list_head                list;
238 #endif
239 };
240 
241 extern struct ftrace_ops __rcu *ftrace_ops_list;
242 extern struct ftrace_ops ftrace_list_end;
243 
244 /*
245  * Traverse the ftrace_ops_list, invoking all entries.  The reason that we
246  * can use rcu_dereference_raw_check() is that elements removed from this list
247  * are simply leaked, so there is no need to interact with a grace-period
248  * mechanism.  The rcu_dereference_raw_check() calls are needed to handle
249  * concurrent insertions into the ftrace_ops_list.
250  *
251  * Silly Alpha and silly pointer-speculation compiler optimizations!
252  */
253 #define do_for_each_ftrace_op(op, list)                 \
254         op = rcu_dereference_raw_check(list);                   \
255         do
256 
257 /*
258  * Optimized for just a single item in the list (as that is the normal case).
259  */
260 #define while_for_each_ftrace_op(op)                            \
261         while (likely(op = rcu_dereference_raw_check((op)->next)) &&    \
262                unlikely((op) != &ftrace_list_end))
263 
264 /*
265  * Type of the current tracing.
266  */
267 enum ftrace_tracing_type_t {
268         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
269         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
270 };
271 
272 /* Current tracing type, default is FTRACE_TYPE_ENTER */
273 extern enum ftrace_tracing_type_t ftrace_tracing_type;
274 
275 /*
276  * The ftrace_ops must be a static and should also
277  * be read_mostly.  These functions do modify read_mostly variables
278  * so use them sparely. Never free an ftrace_op or modify the
279  * next pointer after it has been registered. Even after unregistering
280  * it, the next pointer may still be used internally.
281  */
282 int register_ftrace_function(struct ftrace_ops *ops);
283 int unregister_ftrace_function(struct ftrace_ops *ops);
284 
285 extern void ftrace_stub(unsigned long a0, unsigned long a1,
286                         struct ftrace_ops *op, struct ftrace_regs *fregs);
287 
288 #else /* !CONFIG_FUNCTION_TRACER */
289 /*
290  * (un)register_ftrace_function must be a macro since the ops parameter
291  * must not be evaluated.
292  */
293 #define register_ftrace_function(ops) ({ 0; })
294 #define unregister_ftrace_function(ops) ({ 0; })
295 static inline void ftrace_kill(void) { }
296 static inline void ftrace_free_init_mem(void) { }
297 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
298 #endif /* CONFIG_FUNCTION_TRACER */
299 
300 struct ftrace_func_entry {
301         struct hlist_node hlist;
302         unsigned long ip;
303         unsigned long direct; /* for direct lookup only */
304 };
305 
306 struct dyn_ftrace;
307 
308 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
309 extern int ftrace_direct_func_count;
310 int register_ftrace_direct(unsigned long ip, unsigned long addr);
311 int unregister_ftrace_direct(unsigned long ip, unsigned long addr);
312 int modify_ftrace_direct(unsigned long ip, unsigned long old_addr, unsigned long new_addr);
313 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr);
314 int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
315                                 struct dyn_ftrace *rec,
316                                 unsigned long old_addr,
317                                 unsigned long new_addr);
318 unsigned long ftrace_find_rec_direct(unsigned long ip);
319 #else
320 # define ftrace_direct_func_count 0
321 static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
322 {
323         return -ENOTSUPP;
324 }
325 static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
326 {
327         return -ENOTSUPP;
328 }
329 static inline int modify_ftrace_direct(unsigned long ip,
330                                        unsigned long old_addr, unsigned long new_addr)
331 {
332         return -ENOTSUPP;
333 }
334 static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
335 {
336         return NULL;
337 }
338 static inline int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
339                                               struct dyn_ftrace *rec,
340                                               unsigned long old_addr,
341                                               unsigned long new_addr)
342 {
343         return -ENODEV;
344 }
345 static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
346 {
347         return 0;
348 }
349 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
350 
351 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
352 /*
353  * This must be implemented by the architecture.
354  * It is the way the ftrace direct_ops helper, when called
355  * via ftrace (because there's other callbacks besides the
356  * direct call), can inform the architecture's trampoline that this
357  * routine has a direct caller, and what the caller is.
358  *
359  * For example, in x86, it returns the direct caller
360  * callback function via the regs->orig_ax parameter.
361  * Then in the ftrace trampoline, if this is set, it makes
362  * the return from the trampoline jump to the direct caller
363  * instead of going back to the function it just traced.
364  */
365 static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs,
366                                                  unsigned long addr) { }
367 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
368 
369 #ifdef CONFIG_STACK_TRACER
370 
371 extern int stack_tracer_enabled;
372 
373 int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
374                        size_t *lenp, loff_t *ppos);
375 
376 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
377 DECLARE_PER_CPU(int, disable_stack_tracer);
378 
379 /**
380  * stack_tracer_disable - temporarily disable the stack tracer
381  *
382  * There's a few locations (namely in RCU) where stack tracing
383  * cannot be executed. This function is used to disable stack
384  * tracing during those critical sections.
385  *
386  * This function must be called with preemption or interrupts
387  * disabled and stack_tracer_enable() must be called shortly after
388  * while preemption or interrupts are still disabled.
389  */
390 static inline void stack_tracer_disable(void)
391 {
392         /* Preemption or interrupts must be disabled */
393         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
394                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
395         this_cpu_inc(disable_stack_tracer);
396 }
397 
398 /**
399  * stack_tracer_enable - re-enable the stack tracer
400  *
401  * After stack_tracer_disable() is called, stack_tracer_enable()
402  * must be called shortly afterward.
403  */
404 static inline void stack_tracer_enable(void)
405 {
406         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
407                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
408         this_cpu_dec(disable_stack_tracer);
409 }
410 #else
411 static inline void stack_tracer_disable(void) { }
412 static inline void stack_tracer_enable(void) { }
413 #endif
414 
415 #ifdef CONFIG_DYNAMIC_FTRACE
416 
417 int ftrace_arch_code_modify_prepare(void);
418 int ftrace_arch_code_modify_post_process(void);
419 
420 enum ftrace_bug_type {
421         FTRACE_BUG_UNKNOWN,
422         FTRACE_BUG_INIT,
423         FTRACE_BUG_NOP,
424         FTRACE_BUG_CALL,
425         FTRACE_BUG_UPDATE,
426 };
427 extern enum ftrace_bug_type ftrace_bug_type;
428 
429 /*
430  * Archs can set this to point to a variable that holds the value that was
431  * expected at the call site before calling ftrace_bug().
432  */
433 extern const void *ftrace_expected;
434 
435 void ftrace_bug(int err, struct dyn_ftrace *rec);
436 
437 struct seq_file;
438 
439 extern int ftrace_text_reserved(const void *start, const void *end);
440 
441 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
442 
443 bool is_ftrace_trampoline(unsigned long addr);
444 
445 /*
446  * The dyn_ftrace record's flags field is split into two parts.
447  * the first part which is '0-FTRACE_REF_MAX' is a counter of
448  * the number of callbacks that have registered the function that
449  * the dyn_ftrace descriptor represents.
450  *
451  * The second part is a mask:
452  *  ENABLED - the function is being traced
453  *  REGS    - the record wants the function to save regs
454  *  REGS_EN - the function is set up to save regs.
455  *  IPMODIFY - the record allows for the IP address to be changed.
456  *  DISABLED - the record is not ready to be touched yet
457  *  DIRECT   - there is a direct function to call
458  *
459  * When a new ftrace_ops is registered and wants a function to save
460  * pt_regs, the rec->flags REGS is set. When the function has been
461  * set up to save regs, the REG_EN flag is set. Once a function
462  * starts saving regs it will do so until all ftrace_ops are removed
463  * from tracing that function.
464  */
465 enum {
466         FTRACE_FL_ENABLED       = (1UL << 31),
467         FTRACE_FL_REGS          = (1UL << 30),
468         FTRACE_FL_REGS_EN       = (1UL << 29),
469         FTRACE_FL_TRAMP         = (1UL << 28),
470         FTRACE_FL_TRAMP_EN      = (1UL << 27),
471         FTRACE_FL_IPMODIFY      = (1UL << 26),
472         FTRACE_FL_DISABLED      = (1UL << 25),
473         FTRACE_FL_DIRECT        = (1UL << 24),
474         FTRACE_FL_DIRECT_EN     = (1UL << 23),
475 };
476 
477 #define FTRACE_REF_MAX_SHIFT    23
478 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
479 
480 #define ftrace_rec_count(rec)   ((rec)->flags & FTRACE_REF_MAX)
481 
482 struct dyn_ftrace {
483         unsigned long           ip; /* address of mcount call-site */
484         unsigned long           flags;
485         struct dyn_arch_ftrace  arch;
486 };
487 
488 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
489                          int remove, int reset);
490 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
491                        int len, int reset);
492 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
493                         int len, int reset);
494 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
495 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
496 void ftrace_free_filter(struct ftrace_ops *ops);
497 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
498 
499 enum {
500         FTRACE_UPDATE_CALLS             = (1 << 0),
501         FTRACE_DISABLE_CALLS            = (1 << 1),
502         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
503         FTRACE_START_FUNC_RET           = (1 << 3),
504         FTRACE_STOP_FUNC_RET            = (1 << 4),
505         FTRACE_MAY_SLEEP                = (1 << 5),
506 };
507 
508 /*
509  * The FTRACE_UPDATE_* enum is used to pass information back
510  * from the ftrace_update_record() and ftrace_test_record()
511  * functions. These are called by the code update routines
512  * to find out what is to be done for a given function.
513  *
514  *  IGNORE           - The function is already what we want it to be
515  *  MAKE_CALL        - Start tracing the function
516  *  MODIFY_CALL      - Stop saving regs for the function
517  *  MAKE_NOP         - Stop tracing the function
518  */
519 enum {
520         FTRACE_UPDATE_IGNORE,
521         FTRACE_UPDATE_MAKE_CALL,
522         FTRACE_UPDATE_MODIFY_CALL,
523         FTRACE_UPDATE_MAKE_NOP,
524 };
525 
526 enum {
527         FTRACE_ITER_FILTER      = (1 << 0),
528         FTRACE_ITER_NOTRACE     = (1 << 1),
529         FTRACE_ITER_PRINTALL    = (1 << 2),
530         FTRACE_ITER_DO_PROBES   = (1 << 3),
531         FTRACE_ITER_PROBE       = (1 << 4),
532         FTRACE_ITER_MOD         = (1 << 5),
533         FTRACE_ITER_ENABLED     = (1 << 6),
534 };
535 
536 void arch_ftrace_update_code(int command);
537 void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
538 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
539 void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
540 
541 struct ftrace_rec_iter;
542 
543 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
544 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
545 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
546 
547 #define for_ftrace_rec_iter(iter)               \
548         for (iter = ftrace_rec_iter_start();    \
549              iter;                              \
550              iter = ftrace_rec_iter_next(iter))
551 
552 
553 int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
554 int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
555 void ftrace_run_stop_machine(int command);
556 unsigned long ftrace_location(unsigned long ip);
557 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
558 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
559 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
560 
561 extern ftrace_func_t ftrace_trace_function;
562 
563 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
564                   struct inode *inode, struct file *file);
565 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
566                             size_t cnt, loff_t *ppos);
567 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
568                              size_t cnt, loff_t *ppos);
569 int ftrace_regex_release(struct inode *inode, struct file *file);
570 
571 void __init
572 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
573 
574 /* defined in arch */
575 extern int ftrace_ip_converted(unsigned long ip);
576 extern int ftrace_dyn_arch_init(void);
577 extern void ftrace_replace_code(int enable);
578 extern int ftrace_update_ftrace_func(ftrace_func_t func);
579 extern void ftrace_caller(void);
580 extern void ftrace_regs_caller(void);
581 extern void ftrace_call(void);
582 extern void ftrace_regs_call(void);
583 extern void mcount_call(void);
584 
585 void ftrace_modify_all_code(int command);
586 
587 #ifndef FTRACE_ADDR
588 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
589 #endif
590 
591 #ifndef FTRACE_GRAPH_ADDR
592 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
593 #endif
594 
595 #ifndef FTRACE_REGS_ADDR
596 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
597 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
598 #else
599 # define FTRACE_REGS_ADDR FTRACE_ADDR
600 #endif
601 #endif
602 
603 /*
604  * If an arch would like functions that are only traced
605  * by the function graph tracer to jump directly to its own
606  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
607  * to be that address to jump to.
608  */
609 #ifndef FTRACE_GRAPH_TRAMP_ADDR
610 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
611 #endif
612 
613 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
614 extern void ftrace_graph_caller(void);
615 extern int ftrace_enable_ftrace_graph_caller(void);
616 extern int ftrace_disable_ftrace_graph_caller(void);
617 #else
618 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
619 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
620 #endif
621 
622 /**
623  * ftrace_make_nop - convert code into nop
624  * @mod: module structure if called by module load initialization
625  * @rec: the call site record (e.g. mcount/fentry)
626  * @addr: the address that the call site should be calling
627  *
628  * This is a very sensitive operation and great care needs
629  * to be taken by the arch.  The operation should carefully
630  * read the location, check to see if what is read is indeed
631  * what we expect it to be, and then on success of the compare,
632  * it should write to the location.
633  *
634  * The code segment at @rec->ip should be a caller to @addr
635  *
636  * Return must be:
637  *  0 on success
638  *  -EFAULT on error reading the location
639  *  -EINVAL on a failed compare of the contents
640  *  -EPERM  on error writing to the location
641  * Any other value will be considered a failure.
642  */
643 extern int ftrace_make_nop(struct module *mod,
644                            struct dyn_ftrace *rec, unsigned long addr);
645 
646 /**
647  * ftrace_need_init_nop - return whether nop call sites should be initialized
648  *
649  * Normally the compiler's -mnop-mcount generates suitable nops, so we don't
650  * need to call ftrace_init_nop() if the code is built with that flag.
651  * Architectures where this is not always the case may define their own
652  * condition.
653  *
654  * Return must be:
655  *  0       if ftrace_init_nop() should be called
656  *  Nonzero if ftrace_init_nop() should not be called
657  */
658 
659 #ifndef ftrace_need_init_nop
660 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT))
661 #endif
662 
663 /**
664  * ftrace_init_nop - initialize a nop call site
665  * @mod: module structure if called by module load initialization
666  * @rec: the call site record (e.g. mcount/fentry)
667  *
668  * This is a very sensitive operation and great care needs
669  * to be taken by the arch.  The operation should carefully
670  * read the location, check to see if what is read is indeed
671  * what we expect it to be, and then on success of the compare,
672  * it should write to the location.
673  *
674  * The code segment at @rec->ip should contain the contents created by
675  * the compiler
676  *
677  * Return must be:
678  *  0 on success
679  *  -EFAULT on error reading the location
680  *  -EINVAL on a failed compare of the contents
681  *  -EPERM  on error writing to the location
682  * Any other value will be considered a failure.
683  */
684 #ifndef ftrace_init_nop
685 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
686 {
687         return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
688 }
689 #endif
690 
691 /**
692  * ftrace_make_call - convert a nop call site into a call to addr
693  * @rec: the call site record (e.g. mcount/fentry)
694  * @addr: the address that the call site should call
695  *
696  * This is a very sensitive operation and great care needs
697  * to be taken by the arch.  The operation should carefully
698  * read the location, check to see if what is read is indeed
699  * what we expect it to be, and then on success of the compare,
700  * it should write to the location.
701  *
702  * The code segment at @rec->ip should be a nop
703  *
704  * Return must be:
705  *  0 on success
706  *  -EFAULT on error reading the location
707  *  -EINVAL on a failed compare of the contents
708  *  -EPERM  on error writing to the location
709  * Any other value will be considered a failure.
710  */
711 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
712 
713 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
714 /**
715  * ftrace_modify_call - convert from one addr to another (no nop)
716  * @rec: the call site record (e.g. mcount/fentry)
717  * @old_addr: the address expected to be currently called to
718  * @addr: the address to change to
719  *
720  * This is a very sensitive operation and great care needs
721  * to be taken by the arch.  The operation should carefully
722  * read the location, check to see if what is read is indeed
723  * what we expect it to be, and then on success of the compare,
724  * it should write to the location.
725  *
726  * The code segment at @rec->ip should be a caller to @old_addr
727  *
728  * Return must be:
729  *  0 on success
730  *  -EFAULT on error reading the location
731  *  -EINVAL on a failed compare of the contents
732  *  -EPERM  on error writing to the location
733  * Any other value will be considered a failure.
734  */
735 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
736                               unsigned long addr);
737 #else
738 /* Should never be called */
739 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
740                                      unsigned long addr)
741 {
742         return -EINVAL;
743 }
744 #endif
745 
746 /* May be defined in arch */
747 extern int ftrace_arch_read_dyn_info(char *buf, int size);
748 
749 extern int skip_trace(unsigned long ip);
750 extern void ftrace_module_init(struct module *mod);
751 extern void ftrace_module_enable(struct module *mod);
752 extern void ftrace_release_mod(struct module *mod);
753 
754 extern void ftrace_disable_daemon(void);
755 extern void ftrace_enable_daemon(void);
756 #else /* CONFIG_DYNAMIC_FTRACE */
757 static inline int skip_trace(unsigned long ip) { return 0; }
758 static inline void ftrace_disable_daemon(void) { }
759 static inline void ftrace_enable_daemon(void) { }
760 static inline void ftrace_module_init(struct module *mod) { }
761 static inline void ftrace_module_enable(struct module *mod) { }
762 static inline void ftrace_release_mod(struct module *mod) { }
763 static inline int ftrace_text_reserved(const void *start, const void *end)
764 {
765         return 0;
766 }
767 static inline unsigned long ftrace_location(unsigned long ip)
768 {
769         return 0;
770 }
771 
772 /*
773  * Again users of functions that have ftrace_ops may not
774  * have them defined when ftrace is not enabled, but these
775  * functions may still be called. Use a macro instead of inline.
776  */
777 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
778 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
779 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
780 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
781 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
782 #define ftrace_free_filter(ops) do { } while (0)
783 #define ftrace_ops_set_global_filter(ops) do { } while (0)
784 
785 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
786                             size_t cnt, loff_t *ppos) { return -ENODEV; }
787 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
788                              size_t cnt, loff_t *ppos) { return -ENODEV; }
789 static inline int
790 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
791 
792 static inline bool is_ftrace_trampoline(unsigned long addr)
793 {
794         return false;
795 }
796 #endif /* CONFIG_DYNAMIC_FTRACE */
797 
798 /* totally disable ftrace - can not re-enable after this */
799 void ftrace_kill(void);
800 
801 static inline void tracer_disable(void)
802 {
803 #ifdef CONFIG_FUNCTION_TRACER
804         ftrace_enabled = 0;
805 #endif
806 }
807 
808 /*
809  * Ftrace disable/restore without lock. Some synchronization mechanism
810  * must be used to prevent ftrace_enabled to be changed between
811  * disable/restore.
812  */
813 static inline int __ftrace_enabled_save(void)
814 {
815 #ifdef CONFIG_FUNCTION_TRACER
816         int saved_ftrace_enabled = ftrace_enabled;
817         ftrace_enabled = 0;
818         return saved_ftrace_enabled;
819 #else
820         return 0;
821 #endif
822 }
823 
824 static inline void __ftrace_enabled_restore(int enabled)
825 {
826 #ifdef CONFIG_FUNCTION_TRACER
827         ftrace_enabled = enabled;
828 #endif
829 }
830 
831 /* All archs should have this, but we define it for consistency */
832 #ifndef ftrace_return_address0
833 # define ftrace_return_address0 __builtin_return_address(0)
834 #endif
835 
836 /* Archs may use other ways for ADDR1 and beyond */
837 #ifndef ftrace_return_address
838 # ifdef CONFIG_FRAME_POINTER
839 #  define ftrace_return_address(n) __builtin_return_address(n)
840 # else
841 #  define ftrace_return_address(n) 0UL
842 # endif
843 #endif
844 
845 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
846 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
847 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
848 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
849 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
850 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
851 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
852 
853 static inline unsigned long get_lock_parent_ip(void)
854 {
855         unsigned long addr = CALLER_ADDR0;
856 
857         if (!in_lock_functions(addr))
858                 return addr;
859         addr = CALLER_ADDR1;
860         if (!in_lock_functions(addr))
861                 return addr;
862         return CALLER_ADDR2;
863 }
864 
865 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
866   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
867   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
868 #else
869 /*
870  * Use defines instead of static inlines because some arches will make code out
871  * of the CALLER_ADDR, when we really want these to be a real nop.
872  */
873 # define trace_preempt_on(a0, a1) do { } while (0)
874 # define trace_preempt_off(a0, a1) do { } while (0)
875 #endif
876 
877 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
878 extern void ftrace_init(void);
879 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
880 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries"
881 #else
882 #define FTRACE_CALLSITE_SECTION "__mcount_loc"
883 #endif
884 #else
885 static inline void ftrace_init(void) { }
886 #endif
887 
888 /*
889  * Structure that defines an entry function trace.
890  * It's already packed but the attribute "packed" is needed
891  * to remove extra padding at the end.
892  */
893 struct ftrace_graph_ent {
894         unsigned long func; /* Current function */
895         int depth;
896 } __packed;
897 
898 /*
899  * Structure that defines a return function trace.
900  * It's already packed but the attribute "packed" is needed
901  * to remove extra padding at the end.
902  */
903 struct ftrace_graph_ret {
904         unsigned long func; /* Current function */
905         int depth;
906         /* Number of functions that overran the depth limit for current task */
907         unsigned int overrun;
908         unsigned long long calltime;
909         unsigned long long rettime;
910 } __packed;
911 
912 /* Type of the callback handlers for tracing function graph*/
913 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
914 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
915 
916 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
917 
918 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
919 
920 struct fgraph_ops {
921         trace_func_graph_ent_t          entryfunc;
922         trace_func_graph_ret_t          retfunc;
923 };
924 
925 /*
926  * Stack of return addresses for functions
927  * of a thread.
928  * Used in struct thread_info
929  */
930 struct ftrace_ret_stack {
931         unsigned long ret;
932         unsigned long func;
933         unsigned long long calltime;
934 #ifdef CONFIG_FUNCTION_PROFILER
935         unsigned long long subtime;
936 #endif
937 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
938         unsigned long fp;
939 #endif
940 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
941         unsigned long *retp;
942 #endif
943 };
944 
945 /*
946  * Primary handler of a function return.
947  * It relays on ftrace_return_to_handler.
948  * Defined in entry_32/64.S
949  */
950 extern void return_to_handler(void);
951 
952 extern int
953 function_graph_enter(unsigned long ret, unsigned long func,
954                      unsigned long frame_pointer, unsigned long *retp);
955 
956 struct ftrace_ret_stack *
957 ftrace_graph_get_ret_stack(struct task_struct *task, int idx);
958 
959 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
960                                     unsigned long ret, unsigned long *retp);
961 
962 /*
963  * Sometimes we don't want to trace a function with the function
964  * graph tracer but we want them to keep traced by the usual function
965  * tracer if the function graph tracer is not configured.
966  */
967 #define __notrace_funcgraph             notrace
968 
969 #define FTRACE_RETFUNC_DEPTH 50
970 #define FTRACE_RETSTACK_ALLOC_SIZE 32
971 
972 extern int register_ftrace_graph(struct fgraph_ops *ops);
973 extern void unregister_ftrace_graph(struct fgraph_ops *ops);
974 
975 extern bool ftrace_graph_is_dead(void);
976 extern void ftrace_graph_stop(void);
977 
978 /* The current handlers in use */
979 extern trace_func_graph_ret_t ftrace_graph_return;
980 extern trace_func_graph_ent_t ftrace_graph_entry;
981 
982 extern void ftrace_graph_init_task(struct task_struct *t);
983 extern void ftrace_graph_exit_task(struct task_struct *t);
984 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
985 
986 static inline void pause_graph_tracing(void)
987 {
988         atomic_inc(&current->tracing_graph_pause);
989 }
990 
991 static inline void unpause_graph_tracing(void)
992 {
993         atomic_dec(&current->tracing_graph_pause);
994 }
995 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
996 
997 #define __notrace_funcgraph
998 
999 static inline void ftrace_graph_init_task(struct task_struct *t) { }
1000 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
1001 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
1002 
1003 /* Define as macros as fgraph_ops may not be defined */
1004 #define register_ftrace_graph(ops) ({ -1; })
1005 #define unregister_ftrace_graph(ops) do { } while (0)
1006 
1007 static inline unsigned long
1008 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
1009                       unsigned long *retp)
1010 {
1011         return ret;
1012 }
1013 
1014 static inline void pause_graph_tracing(void) { }
1015 static inline void unpause_graph_tracing(void) { }
1016 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1017 
1018 #ifdef CONFIG_TRACING
1019 
1020 /* flags for current->trace */
1021 enum {
1022         TSK_TRACE_FL_TRACE_BIT  = 0,
1023         TSK_TRACE_FL_GRAPH_BIT  = 1,
1024 };
1025 enum {
1026         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
1027         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
1028 };
1029 
1030 static inline void set_tsk_trace_trace(struct task_struct *tsk)
1031 {
1032         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
1033 }
1034 
1035 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
1036 {
1037         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
1038 }
1039 
1040 static inline int test_tsk_trace_trace(struct task_struct *tsk)
1041 {
1042         return tsk->trace & TSK_TRACE_FL_TRACE;
1043 }
1044 
1045 static inline void set_tsk_trace_graph(struct task_struct *tsk)
1046 {
1047         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
1048 }
1049 
1050 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
1051 {
1052         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
1053 }
1054 
1055 static inline int test_tsk_trace_graph(struct task_struct *tsk)
1056 {
1057         return tsk->trace & TSK_TRACE_FL_GRAPH;
1058 }
1059 
1060 enum ftrace_dump_mode;
1061 
1062 extern enum ftrace_dump_mode ftrace_dump_on_oops;
1063 extern int tracepoint_printk;
1064 
1065 extern void disable_trace_on_warning(void);
1066 extern int __disable_trace_on_warning;
1067 
1068 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
1069                              void *buffer, size_t *lenp, loff_t *ppos);
1070 
1071 #else /* CONFIG_TRACING */
1072 static inline void  disable_trace_on_warning(void) { }
1073 #endif /* CONFIG_TRACING */
1074 
1075 #ifdef CONFIG_FTRACE_SYSCALLS
1076 
1077 unsigned long arch_syscall_addr(int nr);
1078 
1079 #endif /* CONFIG_FTRACE_SYSCALLS */
1080 
1081 #endif /* _LINUX_FTRACE_H */
1082 

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