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