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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.txt
  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 void clear_ftrace_function(void);
227 
228 extern void ftrace_stub(unsigned long a0, unsigned long a1,
229                         struct ftrace_ops *op, struct pt_regs *regs);
230 
231 #else /* !CONFIG_FUNCTION_TRACER */
232 /*
233  * (un)register_ftrace_function must be a macro since the ops parameter
234  * must not be evaluated.
235  */
236 #define register_ftrace_function(ops) ({ 0; })
237 #define unregister_ftrace_function(ops) ({ 0; })
238 static inline int ftrace_nr_registered_ops(void)
239 {
240         return 0;
241 }
242 static inline void clear_ftrace_function(void) { }
243 static inline void ftrace_kill(void) { }
244 static inline void ftrace_free_init_mem(void) { }
245 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
246 #endif /* CONFIG_FUNCTION_TRACER */
247 
248 #ifdef CONFIG_STACK_TRACER
249 
250 #define STACK_TRACE_ENTRIES 500
251 
252 struct stack_trace;
253 
254 extern unsigned stack_trace_index[];
255 extern struct stack_trace stack_trace_max;
256 extern unsigned long stack_trace_max_size;
257 extern arch_spinlock_t stack_trace_max_lock;
258 
259 extern int stack_tracer_enabled;
260 void stack_trace_print(void);
261 int
262 stack_trace_sysctl(struct ctl_table *table, int write,
263                    void __user *buffer, size_t *lenp,
264                    loff_t *ppos);
265 
266 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
267 DECLARE_PER_CPU(int, disable_stack_tracer);
268 
269 /**
270  * stack_tracer_disable - temporarily disable the stack tracer
271  *
272  * There's a few locations (namely in RCU) where stack tracing
273  * cannot be executed. This function is used to disable stack
274  * tracing during those critical sections.
275  *
276  * This function must be called with preemption or interrupts
277  * disabled and stack_tracer_enable() must be called shortly after
278  * while preemption or interrupts are still disabled.
279  */
280 static inline void stack_tracer_disable(void)
281 {
282         /* Preemption or interupts must be disabled */
283         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
284                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
285         this_cpu_inc(disable_stack_tracer);
286 }
287 
288 /**
289  * stack_tracer_enable - re-enable the stack tracer
290  *
291  * After stack_tracer_disable() is called, stack_tracer_enable()
292  * must be called shortly afterward.
293  */
294 static inline void stack_tracer_enable(void)
295 {
296         if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
297                 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
298         this_cpu_dec(disable_stack_tracer);
299 }
300 #else
301 static inline void stack_tracer_disable(void) { }
302 static inline void stack_tracer_enable(void) { }
303 #endif
304 
305 #ifdef CONFIG_DYNAMIC_FTRACE
306 
307 int ftrace_arch_code_modify_prepare(void);
308 int ftrace_arch_code_modify_post_process(void);
309 
310 struct dyn_ftrace;
311 
312 enum ftrace_bug_type {
313         FTRACE_BUG_UNKNOWN,
314         FTRACE_BUG_INIT,
315         FTRACE_BUG_NOP,
316         FTRACE_BUG_CALL,
317         FTRACE_BUG_UPDATE,
318 };
319 extern enum ftrace_bug_type ftrace_bug_type;
320 
321 /*
322  * Archs can set this to point to a variable that holds the value that was
323  * expected at the call site before calling ftrace_bug().
324  */
325 extern const void *ftrace_expected;
326 
327 void ftrace_bug(int err, struct dyn_ftrace *rec);
328 
329 struct seq_file;
330 
331 extern int ftrace_text_reserved(const void *start, const void *end);
332 
333 extern int ftrace_nr_registered_ops(void);
334 
335 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
336 
337 bool is_ftrace_trampoline(unsigned long addr);
338 
339 /*
340  * The dyn_ftrace record's flags field is split into two parts.
341  * the first part which is '0-FTRACE_REF_MAX' is a counter of
342  * the number of callbacks that have registered the function that
343  * the dyn_ftrace descriptor represents.
344  *
345  * The second part is a mask:
346  *  ENABLED - the function is being traced
347  *  REGS    - the record wants the function to save regs
348  *  REGS_EN - the function is set up to save regs.
349  *  IPMODIFY - the record allows for the IP address to be changed.
350  *  DISABLED - the record is not ready to be touched yet
351  *
352  * When a new ftrace_ops is registered and wants a function to save
353  * pt_regs, the rec->flag REGS is set. When the function has been
354  * set up to save regs, the REG_EN flag is set. Once a function
355  * starts saving regs it will do so until all ftrace_ops are removed
356  * from tracing that function.
357  */
358 enum {
359         FTRACE_FL_ENABLED       = (1UL << 31),
360         FTRACE_FL_REGS          = (1UL << 30),
361         FTRACE_FL_REGS_EN       = (1UL << 29),
362         FTRACE_FL_TRAMP         = (1UL << 28),
363         FTRACE_FL_TRAMP_EN      = (1UL << 27),
364         FTRACE_FL_IPMODIFY      = (1UL << 26),
365         FTRACE_FL_DISABLED      = (1UL << 25),
366 };
367 
368 #define FTRACE_REF_MAX_SHIFT    25
369 #define FTRACE_FL_BITS          7
370 #define FTRACE_FL_MASKED_BITS   ((1UL << FTRACE_FL_BITS) - 1)
371 #define FTRACE_FL_MASK          (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
372 #define FTRACE_REF_MAX          ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
373 
374 #define ftrace_rec_count(rec)   ((rec)->flags & ~FTRACE_FL_MASK)
375 
376 struct dyn_ftrace {
377         unsigned long           ip; /* address of mcount call-site */
378         unsigned long           flags;
379         struct dyn_arch_ftrace  arch;
380 };
381 
382 int ftrace_force_update(void);
383 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
384                          int remove, int reset);
385 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
386                        int len, int reset);
387 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
388                         int len, int reset);
389 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
390 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
391 void ftrace_free_filter(struct ftrace_ops *ops);
392 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
393 
394 enum {
395         FTRACE_UPDATE_CALLS             = (1 << 0),
396         FTRACE_DISABLE_CALLS            = (1 << 1),
397         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
398         FTRACE_START_FUNC_RET           = (1 << 3),
399         FTRACE_STOP_FUNC_RET            = (1 << 4),
400 };
401 
402 /*
403  * The FTRACE_UPDATE_* enum is used to pass information back
404  * from the ftrace_update_record() and ftrace_test_record()
405  * functions. These are called by the code update routines
406  * to find out what is to be done for a given function.
407  *
408  *  IGNORE           - The function is already what we want it to be
409  *  MAKE_CALL        - Start tracing the function
410  *  MODIFY_CALL      - Stop saving regs for the function
411  *  MAKE_NOP         - Stop tracing the function
412  */
413 enum {
414         FTRACE_UPDATE_IGNORE,
415         FTRACE_UPDATE_MAKE_CALL,
416         FTRACE_UPDATE_MODIFY_CALL,
417         FTRACE_UPDATE_MAKE_NOP,
418 };
419 
420 enum {
421         FTRACE_ITER_FILTER      = (1 << 0),
422         FTRACE_ITER_NOTRACE     = (1 << 1),
423         FTRACE_ITER_PRINTALL    = (1 << 2),
424         FTRACE_ITER_DO_PROBES   = (1 << 3),
425         FTRACE_ITER_PROBE       = (1 << 4),
426         FTRACE_ITER_MOD         = (1 << 5),
427         FTRACE_ITER_ENABLED     = (1 << 6),
428 };
429 
430 void arch_ftrace_update_code(int command);
431 
432 struct ftrace_rec_iter;
433 
434 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
435 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
436 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
437 
438 #define for_ftrace_rec_iter(iter)               \
439         for (iter = ftrace_rec_iter_start();    \
440              iter;                              \
441              iter = ftrace_rec_iter_next(iter))
442 
443 
444 int ftrace_update_record(struct dyn_ftrace *rec, int enable);
445 int ftrace_test_record(struct dyn_ftrace *rec, int enable);
446 void ftrace_run_stop_machine(int command);
447 unsigned long ftrace_location(unsigned long ip);
448 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
449 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
450 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
451 
452 extern ftrace_func_t ftrace_trace_function;
453 
454 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
455                   struct inode *inode, struct file *file);
456 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
457                             size_t cnt, loff_t *ppos);
458 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
459                              size_t cnt, loff_t *ppos);
460 int ftrace_regex_release(struct inode *inode, struct file *file);
461 
462 void __init
463 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
464 
465 /* defined in arch */
466 extern int ftrace_ip_converted(unsigned long ip);
467 extern int ftrace_dyn_arch_init(void);
468 extern void ftrace_replace_code(int enable);
469 extern int ftrace_update_ftrace_func(ftrace_func_t func);
470 extern void ftrace_caller(void);
471 extern void ftrace_regs_caller(void);
472 extern void ftrace_call(void);
473 extern void ftrace_regs_call(void);
474 extern void mcount_call(void);
475 
476 void ftrace_modify_all_code(int command);
477 
478 #ifndef FTRACE_ADDR
479 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
480 #endif
481 
482 #ifndef FTRACE_GRAPH_ADDR
483 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
484 #endif
485 
486 #ifndef FTRACE_REGS_ADDR
487 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
488 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
489 #else
490 # define FTRACE_REGS_ADDR FTRACE_ADDR
491 #endif
492 #endif
493 
494 /*
495  * If an arch would like functions that are only traced
496  * by the function graph tracer to jump directly to its own
497  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
498  * to be that address to jump to.
499  */
500 #ifndef FTRACE_GRAPH_TRAMP_ADDR
501 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
502 #endif
503 
504 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
505 extern void ftrace_graph_caller(void);
506 extern int ftrace_enable_ftrace_graph_caller(void);
507 extern int ftrace_disable_ftrace_graph_caller(void);
508 #else
509 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
510 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
511 #endif
512 
513 /**
514  * ftrace_make_nop - convert code into nop
515  * @mod: module structure if called by module load initialization
516  * @rec: the mcount call site record
517  * @addr: the address that the call site should be calling
518  *
519  * This is a very sensitive operation and great care needs
520  * to be taken by the arch.  The operation should carefully
521  * read the location, check to see if what is read is indeed
522  * what we expect it to be, and then on success of the compare,
523  * it should write to the location.
524  *
525  * The code segment at @rec->ip should be a caller to @addr
526  *
527  * Return must be:
528  *  0 on success
529  *  -EFAULT on error reading the location
530  *  -EINVAL on a failed compare of the contents
531  *  -EPERM  on error writing to the location
532  * Any other value will be considered a failure.
533  */
534 extern int ftrace_make_nop(struct module *mod,
535                            struct dyn_ftrace *rec, unsigned long addr);
536 
537 /**
538  * ftrace_make_call - convert a nop call site into a call to addr
539  * @rec: the mcount call site record
540  * @addr: the address that the call site should call
541  *
542  * This is a very sensitive operation and great care needs
543  * to be taken by the arch.  The operation should carefully
544  * read the location, check to see if what is read is indeed
545  * what we expect it to be, and then on success of the compare,
546  * it should write to the location.
547  *
548  * The code segment at @rec->ip should be a nop
549  *
550  * Return must be:
551  *  0 on success
552  *  -EFAULT on error reading the location
553  *  -EINVAL on a failed compare of the contents
554  *  -EPERM  on error writing to the location
555  * Any other value will be considered a failure.
556  */
557 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
558 
559 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
560 /**
561  * ftrace_modify_call - convert from one addr to another (no nop)
562  * @rec: the mcount call site record
563  * @old_addr: the address expected to be currently called to
564  * @addr: the address to change to
565  *
566  * This is a very sensitive operation and great care needs
567  * to be taken by the arch.  The operation should carefully
568  * read the location, check to see if what is read is indeed
569  * what we expect it to be, and then on success of the compare,
570  * it should write to the location.
571  *
572  * The code segment at @rec->ip should be a caller to @old_addr
573  *
574  * Return must be:
575  *  0 on success
576  *  -EFAULT on error reading the location
577  *  -EINVAL on a failed compare of the contents
578  *  -EPERM  on error writing to the location
579  * Any other value will be considered a failure.
580  */
581 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
582                               unsigned long addr);
583 #else
584 /* Should never be called */
585 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
586                                      unsigned long addr)
587 {
588         return -EINVAL;
589 }
590 #endif
591 
592 /* May be defined in arch */
593 extern int ftrace_arch_read_dyn_info(char *buf, int size);
594 
595 extern int skip_trace(unsigned long ip);
596 extern void ftrace_module_init(struct module *mod);
597 extern void ftrace_module_enable(struct module *mod);
598 extern void ftrace_release_mod(struct module *mod);
599 
600 extern void ftrace_disable_daemon(void);
601 extern void ftrace_enable_daemon(void);
602 #else /* CONFIG_DYNAMIC_FTRACE */
603 static inline int skip_trace(unsigned long ip) { return 0; }
604 static inline int ftrace_force_update(void) { return 0; }
605 static inline void ftrace_disable_daemon(void) { }
606 static inline void ftrace_enable_daemon(void) { }
607 static inline void ftrace_module_init(struct module *mod) { }
608 static inline void ftrace_module_enable(struct module *mod) { }
609 static inline void ftrace_release_mod(struct module *mod) { }
610 static inline int ftrace_text_reserved(const void *start, const void *end)
611 {
612         return 0;
613 }
614 static inline unsigned long ftrace_location(unsigned long ip)
615 {
616         return 0;
617 }
618 
619 /*
620  * Again users of functions that have ftrace_ops may not
621  * have them defined when ftrace is not enabled, but these
622  * functions may still be called. Use a macro instead of inline.
623  */
624 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
625 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
626 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
627 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
628 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
629 #define ftrace_free_filter(ops) do { } while (0)
630 #define ftrace_ops_set_global_filter(ops) do { } while (0)
631 
632 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
633                             size_t cnt, loff_t *ppos) { return -ENODEV; }
634 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
635                              size_t cnt, loff_t *ppos) { return -ENODEV; }
636 static inline int
637 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
638 
639 static inline bool is_ftrace_trampoline(unsigned long addr)
640 {
641         return false;
642 }
643 #endif /* CONFIG_DYNAMIC_FTRACE */
644 
645 /* totally disable ftrace - can not re-enable after this */
646 void ftrace_kill(void);
647 
648 static inline void tracer_disable(void)
649 {
650 #ifdef CONFIG_FUNCTION_TRACER
651         ftrace_enabled = 0;
652 #endif
653 }
654 
655 /*
656  * Ftrace disable/restore without lock. Some synchronization mechanism
657  * must be used to prevent ftrace_enabled to be changed between
658  * disable/restore.
659  */
660 static inline int __ftrace_enabled_save(void)
661 {
662 #ifdef CONFIG_FUNCTION_TRACER
663         int saved_ftrace_enabled = ftrace_enabled;
664         ftrace_enabled = 0;
665         return saved_ftrace_enabled;
666 #else
667         return 0;
668 #endif
669 }
670 
671 static inline void __ftrace_enabled_restore(int enabled)
672 {
673 #ifdef CONFIG_FUNCTION_TRACER
674         ftrace_enabled = enabled;
675 #endif
676 }
677 
678 /* All archs should have this, but we define it for consistency */
679 #ifndef ftrace_return_address0
680 # define ftrace_return_address0 __builtin_return_address(0)
681 #endif
682 
683 /* Archs may use other ways for ADDR1 and beyond */
684 #ifndef ftrace_return_address
685 # ifdef CONFIG_FRAME_POINTER
686 #  define ftrace_return_address(n) __builtin_return_address(n)
687 # else
688 #  define ftrace_return_address(n) 0UL
689 # endif
690 #endif
691 
692 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
693 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
694 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
695 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
696 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
697 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
698 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
699 
700 static inline unsigned long get_lock_parent_ip(void)
701 {
702         unsigned long addr = CALLER_ADDR0;
703 
704         if (!in_lock_functions(addr))
705                 return addr;
706         addr = CALLER_ADDR1;
707         if (!in_lock_functions(addr))
708                 return addr;
709         return CALLER_ADDR2;
710 }
711 
712 #ifdef CONFIG_IRQSOFF_TRACER
713   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
714   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
715 #else
716   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
717   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
718 #endif
719 
720 #if defined(CONFIG_PREEMPT_TRACER) || \
721         (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
722   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
723   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
724 #else
725 /*
726  * Use defines instead of static inlines because some arches will make code out
727  * of the CALLER_ADDR, when we really want these to be a real nop.
728  */
729 # define trace_preempt_on(a0, a1) do { } while (0)
730 # define trace_preempt_off(a0, a1) do { } while (0)
731 #endif
732 
733 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
734 extern void ftrace_init(void);
735 #else
736 static inline void ftrace_init(void) { }
737 #endif
738 
739 /*
740  * Structure that defines an entry function trace.
741  * It's already packed but the attribute "packed" is needed
742  * to remove extra padding at the end.
743  */
744 struct ftrace_graph_ent {
745         unsigned long func; /* Current function */
746         int depth;
747 } __packed;
748 
749 /*
750  * Structure that defines a return function trace.
751  * It's already packed but the attribute "packed" is needed
752  * to remove extra padding at the end.
753  */
754 struct ftrace_graph_ret {
755         unsigned long func; /* Current function */
756         /* Number of functions that overran the depth limit for current task */
757         unsigned long overrun;
758         unsigned long long calltime;
759         unsigned long long rettime;
760         int depth;
761 } __packed;
762 
763 /* Type of the callback handlers for tracing function graph*/
764 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
765 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
766 
767 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
768 
769 /*
770  * Stack of return addresses for functions
771  * of a thread.
772  * Used in struct thread_info
773  */
774 struct ftrace_ret_stack {
775         unsigned long ret;
776         unsigned long func;
777         unsigned long long calltime;
778 #ifdef CONFIG_FUNCTION_PROFILER
779         unsigned long long subtime;
780 #endif
781 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
782         unsigned long fp;
783 #endif
784 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
785         unsigned long *retp;
786 #endif
787 };
788 
789 /*
790  * Primary handler of a function return.
791  * It relays on ftrace_return_to_handler.
792  * Defined in entry_32/64.S
793  */
794 extern void return_to_handler(void);
795 
796 extern int
797 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
798                          unsigned long frame_pointer, unsigned long *retp);
799 
800 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
801                                     unsigned long ret, unsigned long *retp);
802 
803 /*
804  * Sometimes we don't want to trace a function with the function
805  * graph tracer but we want them to keep traced by the usual function
806  * tracer if the function graph tracer is not configured.
807  */
808 #define __notrace_funcgraph             notrace
809 
810 #define FTRACE_NOTRACE_DEPTH 65536
811 #define FTRACE_RETFUNC_DEPTH 50
812 #define FTRACE_RETSTACK_ALLOC_SIZE 32
813 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
814                                 trace_func_graph_ent_t entryfunc);
815 
816 extern bool ftrace_graph_is_dead(void);
817 extern void ftrace_graph_stop(void);
818 
819 /* The current handlers in use */
820 extern trace_func_graph_ret_t ftrace_graph_return;
821 extern trace_func_graph_ent_t ftrace_graph_entry;
822 
823 extern void unregister_ftrace_graph(void);
824 
825 extern void ftrace_graph_init_task(struct task_struct *t);
826 extern void ftrace_graph_exit_task(struct task_struct *t);
827 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
828 
829 static inline int task_curr_ret_stack(struct task_struct *t)
830 {
831         return t->curr_ret_stack;
832 }
833 
834 static inline void pause_graph_tracing(void)
835 {
836         atomic_inc(&current->tracing_graph_pause);
837 }
838 
839 static inline void unpause_graph_tracing(void)
840 {
841         atomic_dec(&current->tracing_graph_pause);
842 }
843 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
844 
845 #define __notrace_funcgraph
846 
847 static inline void ftrace_graph_init_task(struct task_struct *t) { }
848 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
849 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
850 
851 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
852                           trace_func_graph_ent_t entryfunc)
853 {
854         return -1;
855 }
856 static inline void unregister_ftrace_graph(void) { }
857 
858 static inline int task_curr_ret_stack(struct task_struct *tsk)
859 {
860         return -1;
861 }
862 
863 static inline unsigned long
864 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
865                       unsigned long *retp)
866 {
867         return ret;
868 }
869 
870 static inline void pause_graph_tracing(void) { }
871 static inline void unpause_graph_tracing(void) { }
872 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
873 
874 #ifdef CONFIG_TRACING
875 
876 /* flags for current->trace */
877 enum {
878         TSK_TRACE_FL_TRACE_BIT  = 0,
879         TSK_TRACE_FL_GRAPH_BIT  = 1,
880 };
881 enum {
882         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
883         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
884 };
885 
886 static inline void set_tsk_trace_trace(struct task_struct *tsk)
887 {
888         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
889 }
890 
891 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
892 {
893         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
894 }
895 
896 static inline int test_tsk_trace_trace(struct task_struct *tsk)
897 {
898         return tsk->trace & TSK_TRACE_FL_TRACE;
899 }
900 
901 static inline void set_tsk_trace_graph(struct task_struct *tsk)
902 {
903         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
904 }
905 
906 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
907 {
908         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
909 }
910 
911 static inline int test_tsk_trace_graph(struct task_struct *tsk)
912 {
913         return tsk->trace & TSK_TRACE_FL_GRAPH;
914 }
915 
916 enum ftrace_dump_mode;
917 
918 extern enum ftrace_dump_mode ftrace_dump_on_oops;
919 extern int tracepoint_printk;
920 
921 extern void disable_trace_on_warning(void);
922 extern int __disable_trace_on_warning;
923 
924 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
925                              void __user *buffer, size_t *lenp,
926                              loff_t *ppos);
927 
928 #else /* CONFIG_TRACING */
929 static inline void  disable_trace_on_warning(void) { }
930 #endif /* CONFIG_TRACING */
931 
932 #ifdef CONFIG_FTRACE_SYSCALLS
933 
934 unsigned long arch_syscall_addr(int nr);
935 
936 #endif /* CONFIG_FTRACE_SYSCALLS */
937 
938 #endif /* _LINUX_FTRACE_H */
939 

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