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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_clock.h>
 11 #include <linux/kallsyms.h>
 12 #include <linux/linkage.h>
 13 #include <linux/bitops.h>
 14 #include <linux/ptrace.h>
 15 #include <linux/ktime.h>
 16 #include <linux/sched.h>
 17 #include <linux/types.h>
 18 #include <linux/init.h>
 19 #include <linux/fs.h>
 20 
 21 #include <asm/ftrace.h>
 22 
 23 /*
 24  * If the arch supports passing the variable contents of
 25  * function_trace_op as the third parameter back from the
 26  * mcount call, then the arch should define this as 1.
 27  */
 28 #ifndef ARCH_SUPPORTS_FTRACE_OPS
 29 #define ARCH_SUPPORTS_FTRACE_OPS 0
 30 #endif
 31 
 32 /*
 33  * If the arch's mcount caller does not support all of ftrace's
 34  * features, then it must call an indirect function that
 35  * does. Or at least does enough to prevent any unwelcomed side effects.
 36  */
 37 #if !ARCH_SUPPORTS_FTRACE_OPS
 38 # define FTRACE_FORCE_LIST_FUNC 1
 39 #else
 40 # define FTRACE_FORCE_LIST_FUNC 0
 41 #endif
 42 
 43 /* Main tracing buffer and events set up */
 44 #ifdef CONFIG_TRACING
 45 void trace_init(void);
 46 void early_trace_init(void);
 47 #else
 48 static inline void trace_init(void) { }
 49 static inline void early_trace_init(void) { }
 50 #endif
 51 
 52 struct module;
 53 struct ftrace_hash;
 54 
 55 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
 56         defined(CONFIG_DYNAMIC_FTRACE)
 57 const char *
 58 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
 59                    unsigned long *off, char **modname, char *sym);
 60 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
 61                            char *type, char *name,
 62                            char *module_name, int *exported);
 63 #else
 64 static inline const char *
 65 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
 66                    unsigned long *off, char **modname, char *sym)
 67 {
 68         return NULL;
 69 }
 70 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
 71                                          char *type, char *name,
 72                                          char *module_name, int *exported)
 73 {
 74         return -1;
 75 }
 76 #endif
 77 
 78 
 79 #ifdef CONFIG_FUNCTION_TRACER
 80 
 81 extern int ftrace_enabled;
 82 extern int
 83 ftrace_enable_sysctl(struct ctl_table *table, int write,
 84                      void __user *buffer, size_t *lenp,
 85                      loff_t *ppos);
 86 
 87 struct ftrace_ops;
 88 
 89 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
 90                               struct ftrace_ops *op, struct pt_regs *regs);
 91 
 92 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
 93 
 94 /*
 95  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
 96  * set in the flags member.
 97  * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and
 98  * IPMODIFY are a kind of attribute flags which can be set only before
 99  * registering the ftrace_ops, and can not be modified while registered.
100  * Changing those attribute flags after registering ftrace_ops will
101  * cause unexpected results.
102  *
103  * ENABLED - set/unset when ftrace_ops is registered/unregistered
104  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
105  *           allocated ftrace_ops which need special care
106  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
107  *            and passed to the callback. If this flag is set, but the
108  *            architecture does not support passing regs
109  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
110  *            ftrace_ops will fail to register, unless the next flag
111  *            is set.
112  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
113  *            handler can handle an arch that does not save regs
114  *            (the handler tests if regs == NULL), then it can set
115  *            this flag instead. It will not fail registering the ftrace_ops
116  *            but, the regs field will be NULL if the arch does not support
117  *            passing regs to the handler.
118  *            Note, if this flag is set, the SAVE_REGS flag will automatically
119  *            get set upon registering the ftrace_ops, if the arch supports it.
120  * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
121  *            that the call back has its own recursion protection. If it does
122  *            not set this, then the ftrace infrastructure will add recursion
123  *            protection for the caller.
124  * STUB   - The ftrace_ops is just a place holder.
125  * INITIALIZED - The ftrace_ops has already been initialized (first use time
126  *            register_ftrace_function() is called, it will initialized the ops)
127  * DELETED - The ops are being deleted, do not let them be registered again.
128  * ADDING  - The ops is in the process of being added.
129  * REMOVING - The ops is in the process of being removed.
130  * MODIFYING - The ops is in the process of changing its filter functions.
131  * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
132  *            The arch specific code sets this flag when it allocated a
133  *            trampoline. This lets the arch know that it can update the
134  *            trampoline in case the callback function changes.
135  *            The ftrace_ops trampoline can be set by the ftrace users, and
136  *            in such cases the arch must not modify it. Only the arch ftrace
137  *            core code should set this flag.
138  * IPMODIFY - The ops can modify the IP register. This can only be set with
139  *            SAVE_REGS. If another ops with this flag set is already registered
140  *            for any of the functions that this ops will be registered for, then
141  *            this ops will fail to register or set_filter_ip.
142  * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
143  * RCU     - Set when the ops can only be called when RCU is watching.
144  * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
145  */
146 enum {
147         FTRACE_OPS_FL_ENABLED                   = 1 << 0,
148         FTRACE_OPS_FL_DYNAMIC                   = 1 << 1,
149         FTRACE_OPS_FL_SAVE_REGS                 = 1 << 2,
150         FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = 1 << 3,
151         FTRACE_OPS_FL_RECURSION_SAFE            = 1 << 4,
152         FTRACE_OPS_FL_STUB                      = 1 << 5,
153         FTRACE_OPS_FL_INITIALIZED               = 1 << 6,
154         FTRACE_OPS_FL_DELETED                   = 1 << 7,
155         FTRACE_OPS_FL_ADDING                    = 1 << 8,
156         FTRACE_OPS_FL_REMOVING                  = 1 << 9,
157         FTRACE_OPS_FL_MODIFYING                 = 1 << 10,
158         FTRACE_OPS_FL_ALLOC_TRAMP               = 1 << 11,
159         FTRACE_OPS_FL_IPMODIFY                  = 1 << 12,
160         FTRACE_OPS_FL_PID                       = 1 << 13,
161         FTRACE_OPS_FL_RCU                       = 1 << 14,
162         FTRACE_OPS_FL_TRACE_ARRAY               = 1 << 15,
163 };
164 
165 #ifdef CONFIG_DYNAMIC_FTRACE
166 /* The hash used to know what functions callbacks trace */
167 struct ftrace_ops_hash {
168         struct ftrace_hash __rcu        *notrace_hash;
169         struct ftrace_hash __rcu        *filter_hash;
170         struct mutex                    regex_lock;
171 };
172 
173 void ftrace_free_init_mem(void);
174 void ftrace_free_mem(struct module *mod, void *start, void *end);
175 #else
176 static inline void ftrace_free_init_mem(void) { }
177 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
178 #endif
179 
180 /*
181  * Note, ftrace_ops can be referenced outside of RCU protection, unless
182  * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
183  * core data, the unregistering of it will perform a scheduling on all CPUs
184  * to make sure that there are no more users. Depending on the load of the
185  * system that may take a bit of time.
186  *
187  * Any private data added must also take care not to be freed and if private
188  * data is added to a ftrace_ops that is in core code, the user of the
189  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
190  */
191 struct ftrace_ops {
192         ftrace_func_t                   func;
193         struct ftrace_ops __rcu         *next;
194         unsigned long                   flags;
195         void                            *private;
196         ftrace_func_t                   saved_func;
197 #ifdef CONFIG_DYNAMIC_FTRACE
198         struct ftrace_ops_hash          local_hash;
199         struct ftrace_ops_hash          *func_hash;
200         struct ftrace_ops_hash          old_hash;
201         unsigned long                   trampoline;
202         unsigned long                   trampoline_size;
203 #endif
204 };
205 
206 /*
207  * Type of the current tracing.
208  */
209 enum ftrace_tracing_type_t {
210         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
211         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
212 };
213 
214 /* Current tracing type, default is FTRACE_TYPE_ENTER */
215 extern enum ftrace_tracing_type_t ftrace_tracing_type;
216 
217 /*
218  * The ftrace_ops must be a static and should also
219  * be read_mostly.  These functions do modify read_mostly variables
220  * so use them sparely. Never free an ftrace_op or modify the
221  * next pointer after it has been registered. Even after unregistering
222  * it, the next pointer may still be used internally.
223  */
224 int register_ftrace_function(struct ftrace_ops *ops);
225 int unregister_ftrace_function(struct ftrace_ops *ops);
226 
227 extern void ftrace_stub(unsigned long a0, unsigned long a1,
228                         struct ftrace_ops *op, struct pt_regs *regs);
229 
230 #else /* !CONFIG_FUNCTION_TRACER */
231 /*
232  * (un)register_ftrace_function must be a macro since the ops parameter
233  * must not be evaluated.
234  */
235 #define register_ftrace_function(ops) ({ 0; })
236 #define unregister_ftrace_function(ops) ({ 0; })
237 static inline void ftrace_kill(void) { }
238 static inline void ftrace_free_init_mem(void) { }
239 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
240 #endif /* CONFIG_FUNCTION_TRACER */
241 
242 #ifdef CONFIG_STACK_TRACER
243 
244 #define STACK_TRACE_ENTRIES 500
245 
246 struct stack_trace;
247 
248 extern unsigned stack_trace_index[];
249 extern struct stack_trace stack_trace_max;
250 extern unsigned long stack_trace_max_size;
251 extern arch_spinlock_t stack_trace_max_lock;
252 
253 extern int stack_tracer_enabled;
254 void stack_trace_print(void);
255 int
256 stack_trace_sysctl(struct ctl_table *table, int write,
257                    void __user *buffer, size_t *lenp,
258                    loff_t *ppos);
259 
260 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
261 DECLARE_PER_CPU(int, disable_stack_tracer);
262 
263 /**
264  * stack_tracer_disable - temporarily disable the stack tracer
265  *
266  * There's a few locations (namely in RCU) where stack tracing
267  * cannot be executed. This function is used to disable stack
268  * tracing during those critical sections.
269  *
270  * This function must be called with preemption or interrupts
271  * disabled and stack_tracer_enable() must be called shortly after
272  * while preemption or interrupts are still disabled.
273  */
274 static inline void stack_tracer_disable(void)
275 {
276         /* Preemption or interupts must be disabled */
277         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
278                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
279         this_cpu_inc(disable_stack_tracer);
280 }
281 
282 /**
283  * stack_tracer_enable - re-enable the stack tracer
284  *
285  * After stack_tracer_disable() is called, stack_tracer_enable()
286  * must be called shortly afterward.
287  */
288 static inline void stack_tracer_enable(void)
289 {
290         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
291                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
292         this_cpu_dec(disable_stack_tracer);
293 }
294 #else
295 static inline void stack_tracer_disable(void) { }
296 static inline void stack_tracer_enable(void) { }
297 #endif
298 
299 #ifdef CONFIG_DYNAMIC_FTRACE
300 
301 int ftrace_arch_code_modify_prepare(void);
302 int ftrace_arch_code_modify_post_process(void);
303 
304 struct dyn_ftrace;
305 
306 enum ftrace_bug_type {
307         FTRACE_BUG_UNKNOWN,
308         FTRACE_BUG_INIT,
309         FTRACE_BUG_NOP,
310         FTRACE_BUG_CALL,
311         FTRACE_BUG_UPDATE,
312 };
313 extern enum ftrace_bug_type ftrace_bug_type;
314 
315 /*
316  * Archs can set this to point to a variable that holds the value that was
317  * expected at the call site before calling ftrace_bug().
318  */
319 extern const void *ftrace_expected;
320 
321 void ftrace_bug(int err, struct dyn_ftrace *rec);
322 
323 struct seq_file;
324 
325 extern int ftrace_text_reserved(const void *start, const void *end);
326 
327 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
328 
329 bool is_ftrace_trampoline(unsigned long addr);
330 
331 /*
332  * The dyn_ftrace record's flags field is split into two parts.
333  * the first part which is '0-FTRACE_REF_MAX' is a counter of
334  * the number of callbacks that have registered the function that
335  * the dyn_ftrace descriptor represents.
336  *
337  * The second part is a mask:
338  *  ENABLED - the function is being traced
339  *  REGS    - the record wants the function to save regs
340  *  REGS_EN - the function is set up to save regs.
341  *  IPMODIFY - the record allows for the IP address to be changed.
342  *  DISABLED - the record is not ready to be touched yet
343  *
344  * When a new ftrace_ops is registered and wants a function to save
345  * pt_regs, the rec->flag REGS is set. When the function has been
346  * set up to save regs, the REG_EN flag is set. Once a function
347  * starts saving regs it will do so until all ftrace_ops are removed
348  * from tracing that function.
349  */
350 enum {
351         FTRACE_FL_ENABLED       = (1UL << 31),
352         FTRACE_FL_REGS          = (1UL << 30),
353         FTRACE_FL_REGS_EN       = (1UL << 29),
354         FTRACE_FL_TRAMP         = (1UL << 28),
355         FTRACE_FL_TRAMP_EN      = (1UL << 27),
356         FTRACE_FL_IPMODIFY      = (1UL << 26),
357         FTRACE_FL_DISABLED      = (1UL << 25),
358 };
359 
360 #define FTRACE_REF_MAX_SHIFT    25
361 #define FTRACE_FL_BITS          7
362 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
363 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
364 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
365 
366 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
367 
368 struct dyn_ftrace {
369         unsigned long           ip; /* address of mcount call-site */
370         unsigned long           flags;
371         struct dyn_arch_ftrace  arch;
372 };
373 
374 int ftrace_force_update(void);
375 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
376                          int remove, int reset);
377 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
378                        int len, int reset);
379 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
380                         int len, int reset);
381 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
382 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
383 void ftrace_free_filter(struct ftrace_ops *ops);
384 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
385 
386 enum {
387         FTRACE_UPDATE_CALLS             = (1 << 0),
388         FTRACE_DISABLE_CALLS            = (1 << 1),
389         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
390         FTRACE_START_FUNC_RET           = (1 << 3),
391         FTRACE_STOP_FUNC_RET            = (1 << 4),
392 };
393 
394 /*
395  * The FTRACE_UPDATE_* enum is used to pass information back
396  * from the ftrace_update_record() and ftrace_test_record()
397  * functions. These are called by the code update routines
398  * to find out what is to be done for a given function.
399  *
400  *  IGNORE           - The function is already what we want it to be
401  *  MAKE_CALL        - Start tracing the function
402  *  MODIFY_CALL      - Stop saving regs for the function
403  *  MAKE_NOP         - Stop tracing the function
404  */
405 enum {
406         FTRACE_UPDATE_IGNORE,
407         FTRACE_UPDATE_MAKE_CALL,
408         FTRACE_UPDATE_MODIFY_CALL,
409         FTRACE_UPDATE_MAKE_NOP,
410 };
411 
412 enum {
413         FTRACE_ITER_FILTER      = (1 << 0),
414         FTRACE_ITER_NOTRACE     = (1 << 1),
415         FTRACE_ITER_PRINTALL    = (1 << 2),
416         FTRACE_ITER_DO_PROBES   = (1 << 3),
417         FTRACE_ITER_PROBE       = (1 << 4),
418         FTRACE_ITER_MOD         = (1 << 5),
419         FTRACE_ITER_ENABLED     = (1 << 6),
420 };
421 
422 void arch_ftrace_update_code(int command);
423 
424 struct ftrace_rec_iter;
425 
426 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
427 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
428 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
429 
430 #define for_ftrace_rec_iter(iter)               \
431         for (iter = ftrace_rec_iter_start();    \
432              iter;                              \
433              iter = ftrace_rec_iter_next(iter))
434 
435 
436 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
437 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
438 void ftrace_run_stop_machine(int command);
439 unsigned long ftrace_location(unsigned long ip);
440 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
441 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
442 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
443 
444 extern ftrace_func_t ftrace_trace_function;
445 
446 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
447                   struct inode *inode, struct file *file);
448 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
449                             size_t cnt, loff_t *ppos);
450 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
451                              size_t cnt, loff_t *ppos);
452 int ftrace_regex_release(struct inode *inode, struct file *file);
453 
454 void __init
455 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
456 
457 /* defined in arch */
458 extern int ftrace_ip_converted(unsigned long ip);
459 extern int ftrace_dyn_arch_init(void);
460 extern void ftrace_replace_code(int enable);
461 extern int ftrace_update_ftrace_func(ftrace_func_t func);
462 extern void ftrace_caller(void);
463 extern void ftrace_regs_caller(void);
464 extern void ftrace_call(void);
465 extern void ftrace_regs_call(void);
466 extern void mcount_call(void);
467 
468 void ftrace_modify_all_code(int command);
469 
470 #ifndef FTRACE_ADDR
471 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
472 #endif
473 
474 #ifndef FTRACE_GRAPH_ADDR
475 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
476 #endif
477 
478 #ifndef FTRACE_REGS_ADDR
479 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
480 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
481 #else
482 # define FTRACE_REGS_ADDR FTRACE_ADDR
483 #endif
484 #endif
485 
486 /*
487  * If an arch would like functions that are only traced
488  * by the function graph tracer to jump directly to its own
489  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
490  * to be that address to jump to.
491  */
492 #ifndef FTRACE_GRAPH_TRAMP_ADDR
493 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
494 #endif
495 
496 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
497 extern void ftrace_graph_caller(void);
498 extern int ftrace_enable_ftrace_graph_caller(void);
499 extern int ftrace_disable_ftrace_graph_caller(void);
500 #else
501 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
502 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
503 #endif
504 
505 /**
506  * ftrace_make_nop - convert code into nop
507  * @mod: module structure if called by module load initialization
508  * @rec: the mcount call site record
509  * @addr: the address that the call site should be calling
510  *
511  * This is a very sensitive operation and great care needs
512  * to be taken by the arch.  The operation should carefully
513  * read the location, check to see if what is read is indeed
514  * what we expect it to be, and then on success of the compare,
515  * it should write to the location.
516  *
517  * The code segment at @rec->ip should be a caller to @addr
518  *
519  * Return must be:
520  *  0 on success
521  *  -EFAULT on error reading the location
522  *  -EINVAL on a failed compare of the contents
523  *  -EPERM  on error writing to the location
524  * Any other value will be considered a failure.
525  */
526 extern int ftrace_make_nop(struct module *mod,
527                            struct dyn_ftrace *rec, unsigned long addr);
528 
529 /**
530  * ftrace_make_call - convert a nop call site into a call to addr
531  * @rec: the mcount call site record
532  * @addr: the address that the call site should call
533  *
534  * This is a very sensitive operation and great care needs
535  * to be taken by the arch.  The operation should carefully
536  * read the location, check to see if what is read is indeed
537  * what we expect it to be, and then on success of the compare,
538  * it should write to the location.
539  *
540  * The code segment at @rec->ip should be a nop
541  *
542  * Return must be:
543  *  0 on success
544  *  -EFAULT on error reading the location
545  *  -EINVAL on a failed compare of the contents
546  *  -EPERM  on error writing to the location
547  * Any other value will be considered a failure.
548  */
549 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
550 
551 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
552 /**
553  * ftrace_modify_call - convert from one addr to another (no nop)
554  * @rec: the mcount call site record
555  * @old_addr: the address expected to be currently called to
556  * @addr: the address to change to
557  *
558  * This is a very sensitive operation and great care needs
559  * to be taken by the arch.  The operation should carefully
560  * read the location, check to see if what is read is indeed
561  * what we expect it to be, and then on success of the compare,
562  * it should write to the location.
563  *
564  * The code segment at @rec->ip should be a caller to @old_addr
565  *
566  * Return must be:
567  *  0 on success
568  *  -EFAULT on error reading the location
569  *  -EINVAL on a failed compare of the contents
570  *  -EPERM  on error writing to the location
571  * Any other value will be considered a failure.
572  */
573 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
574                               unsigned long addr);
575 #else
576 /* Should never be called */
577 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
578                                      unsigned long addr)
579 {
580         return -EINVAL;
581 }
582 #endif
583 
584 /* May be defined in arch */
585 extern int ftrace_arch_read_dyn_info(char *buf, int size);
586 
587 extern int skip_trace(unsigned long ip);
588 extern void ftrace_module_init(struct module *mod);
589 extern void ftrace_module_enable(struct module *mod);
590 extern void ftrace_release_mod(struct module *mod);
591 
592 extern void ftrace_disable_daemon(void);
593 extern void ftrace_enable_daemon(void);
594 #else /* CONFIG_DYNAMIC_FTRACE */
595 static inline int skip_trace(unsigned long ip) { return 0; }
596 static inline int ftrace_force_update(void) { return 0; }
597 static inline void ftrace_disable_daemon(void) { }
598 static inline void ftrace_enable_daemon(void) { }
599 static inline void ftrace_module_init(struct module *mod) { }
600 static inline void ftrace_module_enable(struct module *mod) { }
601 static inline void ftrace_release_mod(struct module *mod) { }
602 static inline int ftrace_text_reserved(const void *start, const void *end)
603 {
604         return 0;
605 }
606 static inline unsigned long ftrace_location(unsigned long ip)
607 {
608         return 0;
609 }
610 
611 /*
612  * Again users of functions that have ftrace_ops may not
613  * have them defined when ftrace is not enabled, but these
614  * functions may still be called. Use a macro instead of inline.
615  */
616 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
617 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
618 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
619 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
620 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
621 #define ftrace_free_filter(ops) do { } while (0)
622 #define ftrace_ops_set_global_filter(ops) do { } while (0)
623 
624 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
625                             size_t cnt, loff_t *ppos) { return -ENODEV; }
626 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
627                              size_t cnt, loff_t *ppos) { return -ENODEV; }
628 static inline int
629 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
630 
631 static inline bool is_ftrace_trampoline(unsigned long addr)
632 {
633         return false;
634 }
635 #endif /* CONFIG_DYNAMIC_FTRACE */
636 
637 /* totally disable ftrace - can not re-enable after this */
638 void ftrace_kill(void);
639 
640 static inline void tracer_disable(void)
641 {
642 #ifdef CONFIG_FUNCTION_TRACER
643         ftrace_enabled = 0;
644 #endif
645 }
646 
647 /*
648  * Ftrace disable/restore without lock. Some synchronization mechanism
649  * must be used to prevent ftrace_enabled to be changed between
650  * disable/restore.
651  */
652 static inline int __ftrace_enabled_save(void)
653 {
654 #ifdef CONFIG_FUNCTION_TRACER
655         int saved_ftrace_enabled = ftrace_enabled;
656         ftrace_enabled = 0;
657         return saved_ftrace_enabled;
658 #else
659         return 0;
660 #endif
661 }
662 
663 static inline void __ftrace_enabled_restore(int enabled)
664 {
665 #ifdef CONFIG_FUNCTION_TRACER
666         ftrace_enabled = enabled;
667 #endif
668 }
669 
670 /* All archs should have this, but we define it for consistency */
671 #ifndef ftrace_return_address0
672 # define ftrace_return_address0 __builtin_return_address(0)
673 #endif
674 
675 /* Archs may use other ways for ADDR1 and beyond */
676 #ifndef ftrace_return_address
677 # ifdef CONFIG_FRAME_POINTER
678 #  define ftrace_return_address(n) __builtin_return_address(n)
679 # else
680 #  define ftrace_return_address(n) 0UL
681 # endif
682 #endif
683 
684 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
685 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
686 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
687 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
688 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
689 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
690 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
691 
692 static inline unsigned long get_lock_parent_ip(void)
693 {
694         unsigned long addr = CALLER_ADDR0;
695 
696         if (!in_lock_functions(addr))
697                 return addr;
698         addr = CALLER_ADDR1;
699         if (!in_lock_functions(addr))
700                 return addr;
701         return CALLER_ADDR2;
702 }
703 
704 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
705   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
706   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
707 #else
708 /*
709  * Use defines instead of static inlines because some arches will make code out
710  * of the CALLER_ADDR, when we really want these to be a real nop.
711  */
712 # define trace_preempt_on(a0, a1) do { } while (0)
713 # define trace_preempt_off(a0, a1) do { } while (0)
714 #endif
715 
716 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
717 extern void ftrace_init(void);
718 #else
719 static inline void ftrace_init(void) { }
720 #endif
721 
722 /*
723  * Structure that defines an entry function trace.
724  * It's already packed but the attribute "packed" is needed
725  * to remove extra padding at the end.
726  */
727 struct ftrace_graph_ent {
728         unsigned long func; /* Current function */
729         int depth;
730 } __packed;
731 
732 /*
733  * Structure that defines a return function trace.
734  * It's already packed but the attribute "packed" is needed
735  * to remove extra padding at the end.
736  */
737 struct ftrace_graph_ret {
738         unsigned long func; /* Current function */
739         /* Number of functions that overran the depth limit for current task */
740         unsigned long overrun;
741         unsigned long long calltime;
742         unsigned long long rettime;
743         int depth;
744 } __packed;
745 
746 /* Type of the callback handlers for tracing function graph*/
747 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
748 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
749 
750 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
751 
752 /*
753  * Stack of return addresses for functions
754  * of a thread.
755  * Used in struct thread_info
756  */
757 struct ftrace_ret_stack {
758         unsigned long ret;
759         unsigned long func;
760         unsigned long long calltime;
761 #ifdef CONFIG_FUNCTION_PROFILER
762         unsigned long long subtime;
763 #endif
764 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
765         unsigned long fp;
766 #endif
767 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
768         unsigned long *retp;
769 #endif
770 };
771 
772 /*
773  * Primary handler of a function return.
774  * It relays on ftrace_return_to_handler.
775  * Defined in entry_32/64.S
776  */
777 extern void return_to_handler(void);
778 
779 extern int
780 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
781                          unsigned long frame_pointer, unsigned long *retp);
782 
783 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
784                                     unsigned long ret, unsigned long *retp);
785 
786 /*
787  * Sometimes we don't want to trace a function with the function
788  * graph tracer but we want them to keep traced by the usual function
789  * tracer if the function graph tracer is not configured.
790  */
791 #define __notrace_funcgraph             notrace
792 
793 #define FTRACE_NOTRACE_DEPTH 65536
794 #define FTRACE_RETFUNC_DEPTH 50
795 #define FTRACE_RETSTACK_ALLOC_SIZE 32
796 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
797                                 trace_func_graph_ent_t entryfunc);
798 
799 extern bool ftrace_graph_is_dead(void);
800 extern void ftrace_graph_stop(void);
801 
802 /* The current handlers in use */
803 extern trace_func_graph_ret_t ftrace_graph_return;
804 extern trace_func_graph_ent_t ftrace_graph_entry;
805 
806 extern void unregister_ftrace_graph(void);
807 
808 extern void ftrace_graph_init_task(struct task_struct *t);
809 extern void ftrace_graph_exit_task(struct task_struct *t);
810 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
811 
812 static inline int task_curr_ret_stack(struct task_struct *t)
813 {
814         return t->curr_ret_stack;
815 }
816 
817 static inline void pause_graph_tracing(void)
818 {
819         atomic_inc(&current->tracing_graph_pause);
820 }
821 
822 static inline void unpause_graph_tracing(void)
823 {
824         atomic_dec(&current->tracing_graph_pause);
825 }
826 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
827 
828 #define __notrace_funcgraph
829 
830 static inline void ftrace_graph_init_task(struct task_struct *t) { }
831 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
832 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
833 
834 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
835                           trace_func_graph_ent_t entryfunc)
836 {
837         return -1;
838 }
839 static inline void unregister_ftrace_graph(void) { }
840 
841 static inline int task_curr_ret_stack(struct task_struct *tsk)
842 {
843         return -1;
844 }
845 
846 static inline unsigned long
847 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
848                       unsigned long *retp)
849 {
850         return ret;
851 }
852 
853 static inline void pause_graph_tracing(void) { }
854 static inline void unpause_graph_tracing(void) { }
855 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
856 
857 #ifdef CONFIG_TRACING
858 
859 /* flags for current->trace */
860 enum {
861         TSK_TRACE_FL_TRACE_BIT  = 0,
862         TSK_TRACE_FL_GRAPH_BIT  = 1,
863 };
864 enum {
865         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
866         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
867 };
868 
869 static inline void set_tsk_trace_trace(struct task_struct *tsk)
870 {
871         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
872 }
873 
874 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
875 {
876         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
877 }
878 
879 static inline int test_tsk_trace_trace(struct task_struct *tsk)
880 {
881         return tsk->trace & TSK_TRACE_FL_TRACE;
882 }
883 
884 static inline void set_tsk_trace_graph(struct task_struct *tsk)
885 {
886         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
887 }
888 
889 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
890 {
891         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
892 }
893 
894 static inline int test_tsk_trace_graph(struct task_struct *tsk)
895 {
896         return tsk->trace & TSK_TRACE_FL_GRAPH;
897 }
898 
899 enum ftrace_dump_mode;
900 
901 extern enum ftrace_dump_mode ftrace_dump_on_oops;
902 extern int tracepoint_printk;
903 
904 extern void disable_trace_on_warning(void);
905 extern int __disable_trace_on_warning;
906 
907 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
908                              void __user *buffer, size_t *lenp,
909                              loff_t *ppos);
910 
911 #else /* CONFIG_TRACING */
912 static inline void  disable_trace_on_warning(void) { }
913 #endif /* CONFIG_TRACING */
914 
915 #ifdef CONFIG_FTRACE_SYSCALLS
916 
917 unsigned long arch_syscall_addr(int nr);
918 
919 #endif /* CONFIG_FTRACE_SYSCALLS */
920 
921 #endif /* _LINUX_FTRACE_H */
922 

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