1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Ftrace header. For implementation details beyond the random comments
4 * scattered below, see: Documentation/trace/ftrace-design.rst
5 */
6
7#ifndef _LINUX_FTRACE_H
8#define _LINUX_FTRACE_H
9
10#include <linux/trace_recursion.h>
11#include <linux/trace_clock.h>
12#include <linux/jump_label.h>
13#include <linux/kallsyms.h>
14#include <linux/linkage.h>
15#include <linux/bitops.h>
16#include <linux/ptrace.h>
17#include <linux/ktime.h>
18#include <linux/sched.h>
19#include <linux/types.h>
20#include <linux/init.h>
21#include <linux/fs.h>
22
23#include <asm/ftrace.h>
24
25/*
26 * If the arch supports passing the variable contents of
27 * function_trace_op as the third parameter back from the
28 * mcount call, then the arch should define this as 1.
29 */
30#ifndef ARCH_SUPPORTS_FTRACE_OPS
31#define ARCH_SUPPORTS_FTRACE_OPS 0
32#endif
33
34#ifdef CONFIG_TRACING
35extern void ftrace_boot_snapshot(void);
36#else
37static inline void ftrace_boot_snapshot(void) { }
38#endif
39
40struct ftrace_ops;
41struct ftrace_regs;
42struct dyn_ftrace;
43
44char *arch_ftrace_match_adjust(char *str, const char *search);
45
46#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL
47struct fgraph_ret_regs;
48unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs);
49#else
50unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
51#endif
52
53#ifdef CONFIG_FUNCTION_TRACER
54/*
55 * If the arch's mcount caller does not support all of ftrace's
56 * features, then it must call an indirect function that
57 * does. Or at least does enough to prevent any unwelcome side effects.
58 *
59 * Also define the function prototype that these architectures use
60 * to call the ftrace_ops_list_func().
61 */
62#if !ARCH_SUPPORTS_FTRACE_OPS
63# define FTRACE_FORCE_LIST_FUNC 1
64void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
65#else
66# define FTRACE_FORCE_LIST_FUNC 0
67void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
68 struct ftrace_ops *op, struct ftrace_regs *fregs);
69#endif
70extern const struct ftrace_ops ftrace_nop_ops;
71extern const struct ftrace_ops ftrace_list_ops;
72struct ftrace_ops *ftrace_find_unique_ops(struct dyn_ftrace *rec);
73#endif /* CONFIG_FUNCTION_TRACER */
74
75/* Main tracing buffer and events set up */
76#ifdef CONFIG_TRACING
77void trace_init(void);
78void early_trace_init(void);
79#else
80static inline void trace_init(void) { }
81static inline void early_trace_init(void) { }
82#endif
83
84struct module;
85struct ftrace_hash;
86struct ftrace_direct_func;
87
88#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
89 defined(CONFIG_DYNAMIC_FTRACE)
90const char *
91ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
92 unsigned long *off, char **modname, char *sym);
93#else
94static inline const char *
95ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
96 unsigned long *off, char **modname, char *sym)
97{
98 return NULL;
99}
100#endif
101
102#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
103int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
104 char *type, char *name,
105 char *module_name, int *exported);
106#else
107static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
108 char *type, char *name,
109 char *module_name, int *exported)
110{
111 return -1;
112}
113#endif
114
115#ifdef CONFIG_FUNCTION_TRACER
116
117extern int ftrace_enabled;
118
119#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
120
121struct ftrace_regs {
122 struct pt_regs regs;
123};
124#define arch_ftrace_get_regs(fregs) (&(fregs)->regs)
125
126/*
127 * ftrace_regs_set_instruction_pointer() is to be defined by the architecture
128 * if to allow setting of the instruction pointer from the ftrace_regs when
129 * HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports live kernel patching.
130 */
131#define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0)
132#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
133
134static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
135{
136 if (!fregs)
137 return NULL;
138
139 return arch_ftrace_get_regs(fregs);
140}
141
142/*
143 * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs.
144 * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs.
145 */
146static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
147{
148 if (IS_ENABLED(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS))
149 return true;
150
151 return ftrace_get_regs(fregs) != NULL;
152}
153
154#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
155#define ftrace_regs_get_instruction_pointer(fregs) \
156 instruction_pointer(ftrace_get_regs(fregs))
157#define ftrace_regs_get_argument(fregs, n) \
158 regs_get_kernel_argument(ftrace_get_regs(fregs), n)
159#define ftrace_regs_get_stack_pointer(fregs) \
160 kernel_stack_pointer(ftrace_get_regs(fregs))
161#define ftrace_regs_return_value(fregs) \
162 regs_return_value(ftrace_get_regs(fregs))
163#define ftrace_regs_set_return_value(fregs, ret) \
164 regs_set_return_value(ftrace_get_regs(fregs), ret)
165#define ftrace_override_function_with_return(fregs) \
166 override_function_with_return(ftrace_get_regs(fregs))
167#define ftrace_regs_query_register_offset(name) \
168 regs_query_register_offset(name)
169#endif
170
171typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
172 struct ftrace_ops *op, struct ftrace_regs *fregs);
173
174ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
175
176/*
177 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
178 * set in the flags member.
179 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
180 * IPMODIFY are a kind of attribute flags which can be set only before
181 * registering the ftrace_ops, and can not be modified while registered.
182 * Changing those attribute flags after registering ftrace_ops will
183 * cause unexpected results.
184 *
185 * ENABLED - set/unset when ftrace_ops is registered/unregistered
186 * DYNAMIC - set when ftrace_ops is registered to denote dynamically
187 * allocated ftrace_ops which need special care
188 * SAVE_REGS - The ftrace_ops wants regs saved at each function called
189 * and passed to the callback. If this flag is set, but the
190 * architecture does not support passing regs
191 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
192 * ftrace_ops will fail to register, unless the next flag
193 * is set.
194 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
195 * handler can handle an arch that does not save regs
196 * (the handler tests if regs == NULL), then it can set
197 * this flag instead. It will not fail registering the ftrace_ops
198 * but, the regs field will be NULL if the arch does not support
199 * passing regs to the handler.
200 * Note, if this flag is set, the SAVE_REGS flag will automatically
201 * get set upon registering the ftrace_ops, if the arch supports it.
202 * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
203 * that the call back needs recursion protection. If it does
204 * not set this, then the ftrace infrastructure will assume
205 * that the callback can handle recursion on its own.
206 * STUB - The ftrace_ops is just a place holder.
207 * INITIALIZED - The ftrace_ops has already been initialized (first use time
208 * register_ftrace_function() is called, it will initialized the ops)
209 * DELETED - The ops are being deleted, do not let them be registered again.
210 * ADDING - The ops is in the process of being added.
211 * REMOVING - The ops is in the process of being removed.
212 * MODIFYING - The ops is in the process of changing its filter functions.
213 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
214 * The arch specific code sets this flag when it allocated a
215 * trampoline. This lets the arch know that it can update the
216 * trampoline in case the callback function changes.
217 * The ftrace_ops trampoline can be set by the ftrace users, and
218 * in such cases the arch must not modify it. Only the arch ftrace
219 * core code should set this flag.
220 * IPMODIFY - The ops can modify the IP register. This can only be set with
221 * SAVE_REGS. If another ops with this flag set is already registered
222 * for any of the functions that this ops will be registered for, then
223 * this ops will fail to register or set_filter_ip.
224 * PID - Is affected by set_ftrace_pid (allows filtering on those pids)
225 * RCU - Set when the ops can only be called when RCU is watching.
226 * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
227 * PERMANENT - Set when the ops is permanent and should not be affected by
228 * ftrace_enabled.
229 * DIRECT - Used by the direct ftrace_ops helper for direct functions
230 * (internal ftrace only, should not be used by others)
231 */
232enum {
233 FTRACE_OPS_FL_ENABLED = BIT(0),
234 FTRACE_OPS_FL_DYNAMIC = BIT(1),
235 FTRACE_OPS_FL_SAVE_REGS = BIT(2),
236 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3),
237 FTRACE_OPS_FL_RECURSION = BIT(4),
238 FTRACE_OPS_FL_STUB = BIT(5),
239 FTRACE_OPS_FL_INITIALIZED = BIT(6),
240 FTRACE_OPS_FL_DELETED = BIT(7),
241 FTRACE_OPS_FL_ADDING = BIT(8),
242 FTRACE_OPS_FL_REMOVING = BIT(9),
243 FTRACE_OPS_FL_MODIFYING = BIT(10),
244 FTRACE_OPS_FL_ALLOC_TRAMP = BIT(11),
245 FTRACE_OPS_FL_IPMODIFY = BIT(12),
246 FTRACE_OPS_FL_PID = BIT(13),
247 FTRACE_OPS_FL_RCU = BIT(14),
248 FTRACE_OPS_FL_TRACE_ARRAY = BIT(15),
249 FTRACE_OPS_FL_PERMANENT = BIT(16),
250 FTRACE_OPS_FL_DIRECT = BIT(17),
251};
252
253#ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
254#define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS
255#else
256#define FTRACE_OPS_FL_SAVE_ARGS 0
257#endif
258
259/*
260 * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes
261 * to a ftrace_ops. Note, the requests may fail.
262 *
263 * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same
264 * function as an ops with IPMODIFY. Called
265 * when the DIRECT ops is being registered.
266 * This is called with both direct_mutex and
267 * ftrace_lock are locked.
268 *
269 * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same
270 * function as an ops with IPMODIFY. Called
271 * when the other ops (the one with IPMODIFY)
272 * is being registered.
273 * This is called with direct_mutex locked.
274 *
275 * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same
276 * function as an ops with IPMODIFY. Called
277 * when the other ops (the one with IPMODIFY)
278 * is being unregistered.
279 * This is called with direct_mutex locked.
280 */
281enum ftrace_ops_cmd {
282 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF,
283 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER,
284 FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER,
285};
286
287/*
288 * For most ftrace_ops_cmd,
289 * Returns:
290 * 0 - Success.
291 * Negative on failure. The return value is dependent on the
292 * callback.
293 */
294typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd);
295
296#ifdef CONFIG_DYNAMIC_FTRACE
297/* The hash used to know what functions callbacks trace */
298struct ftrace_ops_hash {
299 struct ftrace_hash __rcu *notrace_hash;
300 struct ftrace_hash __rcu *filter_hash;
301 struct mutex regex_lock;
302};
303
304void ftrace_free_init_mem(void);
305void ftrace_free_mem(struct module *mod, void *start, void *end);
306#else
307static inline void ftrace_free_init_mem(void)
308{
309 ftrace_boot_snapshot();
310}
311static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
312#endif
313
314/*
315 * Note, ftrace_ops can be referenced outside of RCU protection, unless
316 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
317 * core data, the unregistering of it will perform a scheduling on all CPUs
318 * to make sure that there are no more users. Depending on the load of the
319 * system that may take a bit of time.
320 *
321 * Any private data added must also take care not to be freed and if private
322 * data is added to a ftrace_ops that is in core code, the user of the
323 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
324 */
325struct ftrace_ops {
326 ftrace_func_t func;
327 struct ftrace_ops __rcu *next;
328 unsigned long flags;
329 void *private;
330 ftrace_func_t saved_func;
331#ifdef CONFIG_DYNAMIC_FTRACE
332 struct ftrace_ops_hash local_hash;
333 struct ftrace_ops_hash *func_hash;
334 struct ftrace_ops_hash old_hash;
335 unsigned long trampoline;
336 unsigned long trampoline_size;
337 struct list_head list;
338 ftrace_ops_func_t ops_func;
339#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
340 unsigned long direct_call;
341#endif
342#endif
343};
344
345extern struct ftrace_ops __rcu *ftrace_ops_list;
346extern struct ftrace_ops ftrace_list_end;
347
348/*
349 * Traverse the ftrace_ops_list, invoking all entries. The reason that we
350 * can use rcu_dereference_raw_check() is that elements removed from this list
351 * are simply leaked, so there is no need to interact with a grace-period
352 * mechanism. The rcu_dereference_raw_check() calls are needed to handle
353 * concurrent insertions into the ftrace_ops_list.
354 *
355 * Silly Alpha and silly pointer-speculation compiler optimizations!
356 */
357#define do_for_each_ftrace_op(op, list) \
358 op = rcu_dereference_raw_check(list); \
359 do
360
361/*
362 * Optimized for just a single item in the list (as that is the normal case).
363 */
364#define while_for_each_ftrace_op(op) \
365 while (likely(op = rcu_dereference_raw_check((op)->next)) && \
366 unlikely((op) != &ftrace_list_end))
367
368/*
369 * Type of the current tracing.
370 */
371enum ftrace_tracing_type_t {
372 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
373 FTRACE_TYPE_RETURN, /* Hook the return of the function */
374};
375
376/* Current tracing type, default is FTRACE_TYPE_ENTER */
377extern enum ftrace_tracing_type_t ftrace_tracing_type;
378
379/*
380 * The ftrace_ops must be a static and should also
381 * be read_mostly. These functions do modify read_mostly variables
382 * so use them sparely. Never free an ftrace_op or modify the
383 * next pointer after it has been registered. Even after unregistering
384 * it, the next pointer may still be used internally.
385 */
386int register_ftrace_function(struct ftrace_ops *ops);
387int unregister_ftrace_function(struct ftrace_ops *ops);
388
389extern void ftrace_stub(unsigned long a0, unsigned long a1,
390 struct ftrace_ops *op, struct ftrace_regs *fregs);
391
392
393int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs);
394#else /* !CONFIG_FUNCTION_TRACER */
395/*
396 * (un)register_ftrace_function must be a macro since the ops parameter
397 * must not be evaluated.
398 */
399#define register_ftrace_function(ops) ({ 0; })
400#define unregister_ftrace_function(ops) ({ 0; })
401static inline void ftrace_kill(void) { }
402static inline void ftrace_free_init_mem(void) { }
403static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
404static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
405{
406 return -EOPNOTSUPP;
407}
408#endif /* CONFIG_FUNCTION_TRACER */
409
410struct ftrace_func_entry {
411 struct hlist_node hlist;
412 unsigned long ip;
413 unsigned long direct; /* for direct lookup only */
414};
415
416#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
417extern int ftrace_direct_func_count;
418unsigned long ftrace_find_rec_direct(unsigned long ip);
419int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
420int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
421 bool free_filters);
422int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
423int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr);
424
425void ftrace_stub_direct_tramp(void);
426
427#else
428struct ftrace_ops;
429# define ftrace_direct_func_count 0
430static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
431{
432 return 0;
433}
434static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
435{
436 return -ENODEV;
437}
438static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
439 bool free_filters)
440{
441 return -ENODEV;
442}
443static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
444{
445 return -ENODEV;
446}
447static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
448{
449 return -ENODEV;
450}
451
452/*
453 * This must be implemented by the architecture.
454 * It is the way the ftrace direct_ops helper, when called
455 * via ftrace (because there's other callbacks besides the
456 * direct call), can inform the architecture's trampoline that this
457 * routine has a direct caller, and what the caller is.
458 *
459 * For example, in x86, it returns the direct caller
460 * callback function via the regs->orig_ax parameter.
461 * Then in the ftrace trampoline, if this is set, it makes
462 * the return from the trampoline jump to the direct caller
463 * instead of going back to the function it just traced.
464 */
465static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
466 unsigned long addr) { }
467#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
468
469#ifdef CONFIG_STACK_TRACER
470
471extern int stack_tracer_enabled;
472
473int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
474 size_t *lenp, loff_t *ppos);
475
476/* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
477DECLARE_PER_CPU(int, disable_stack_tracer);
478
479/**
480 * stack_tracer_disable - temporarily disable the stack tracer
481 *
482 * There's a few locations (namely in RCU) where stack tracing
483 * cannot be executed. This function is used to disable stack
484 * tracing during those critical sections.
485 *
486 * This function must be called with preemption or interrupts
487 * disabled and stack_tracer_enable() must be called shortly after
488 * while preemption or interrupts are still disabled.
489 */
490static inline void stack_tracer_disable(void)
491{
492 /* Preemption or interrupts must be disabled */
493 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
494 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
495 this_cpu_inc(disable_stack_tracer);
496}
497
498/**
499 * stack_tracer_enable - re-enable the stack tracer
500 *
501 * After stack_tracer_disable() is called, stack_tracer_enable()
502 * must be called shortly afterward.
503 */
504static inline void stack_tracer_enable(void)
505{
506 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
507 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
508 this_cpu_dec(disable_stack_tracer);
509}
510#else
511static inline void stack_tracer_disable(void) { }
512static inline void stack_tracer_enable(void) { }
513#endif
514
515#ifdef CONFIG_DYNAMIC_FTRACE
516
517void ftrace_arch_code_modify_prepare(void);
518void ftrace_arch_code_modify_post_process(void);
519
520enum ftrace_bug_type {
521 FTRACE_BUG_UNKNOWN,
522 FTRACE_BUG_INIT,
523 FTRACE_BUG_NOP,
524 FTRACE_BUG_CALL,
525 FTRACE_BUG_UPDATE,
526};
527extern enum ftrace_bug_type ftrace_bug_type;
528
529/*
530 * Archs can set this to point to a variable that holds the value that was
531 * expected at the call site before calling ftrace_bug().
532 */
533extern const void *ftrace_expected;
534
535void ftrace_bug(int err, struct dyn_ftrace *rec);
536
537struct seq_file;
538
539extern int ftrace_text_reserved(const void *start, const void *end);
540
541struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
542
543bool is_ftrace_trampoline(unsigned long addr);
544
545/*
546 * The dyn_ftrace record's flags field is split into two parts.
547 * the first part which is '0-FTRACE_REF_MAX' is a counter of
548 * the number of callbacks that have registered the function that
549 * the dyn_ftrace descriptor represents.
550 *
551 * The second part is a mask:
552 * ENABLED - the function is being traced
553 * REGS - the record wants the function to save regs
554 * REGS_EN - the function is set up to save regs.
555 * IPMODIFY - the record allows for the IP address to be changed.
556 * DISABLED - the record is not ready to be touched yet
557 * DIRECT - there is a direct function to call
558 * CALL_OPS - the record can use callsite-specific ops
559 * CALL_OPS_EN - the function is set up to use callsite-specific ops
560 * TOUCHED - A callback was added since boot up
561 * MODIFIED - The function had IPMODIFY or DIRECT attached to it
562 *
563 * When a new ftrace_ops is registered and wants a function to save
564 * pt_regs, the rec->flags REGS is set. When the function has been
565 * set up to save regs, the REG_EN flag is set. Once a function
566 * starts saving regs it will do so until all ftrace_ops are removed
567 * from tracing that function.
568 */
569enum {
570 FTRACE_FL_ENABLED = (1UL << 31),
571 FTRACE_FL_REGS = (1UL << 30),
572 FTRACE_FL_REGS_EN = (1UL << 29),
573 FTRACE_FL_TRAMP = (1UL << 28),
574 FTRACE_FL_TRAMP_EN = (1UL << 27),
575 FTRACE_FL_IPMODIFY = (1UL << 26),
576 FTRACE_FL_DISABLED = (1UL << 25),
577 FTRACE_FL_DIRECT = (1UL << 24),
578 FTRACE_FL_DIRECT_EN = (1UL << 23),
579 FTRACE_FL_CALL_OPS = (1UL << 22),
580 FTRACE_FL_CALL_OPS_EN = (1UL << 21),
581 FTRACE_FL_TOUCHED = (1UL << 20),
582 FTRACE_FL_MODIFIED = (1UL << 19),
583};
584
585#define FTRACE_REF_MAX_SHIFT 19
586#define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
587
588#define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX)
589
590struct dyn_ftrace {
591 unsigned long ip; /* address of mcount call-site */
592 unsigned long flags;
593 struct dyn_arch_ftrace arch;
594};
595
596int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
597 int remove, int reset);
598int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
599 unsigned int cnt, int remove, int reset);
600int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
601 int len, int reset);
602int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
603 int len, int reset);
604void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
605void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
606void ftrace_free_filter(struct ftrace_ops *ops);
607void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
608
609enum {
610 FTRACE_UPDATE_CALLS = (1 << 0),
611 FTRACE_DISABLE_CALLS = (1 << 1),
612 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
613 FTRACE_START_FUNC_RET = (1 << 3),
614 FTRACE_STOP_FUNC_RET = (1 << 4),
615 FTRACE_MAY_SLEEP = (1 << 5),
616};
617
618/*
619 * The FTRACE_UPDATE_* enum is used to pass information back
620 * from the ftrace_update_record() and ftrace_test_record()
621 * functions. These are called by the code update routines
622 * to find out what is to be done for a given function.
623 *
624 * IGNORE - The function is already what we want it to be
625 * MAKE_CALL - Start tracing the function
626 * MODIFY_CALL - Stop saving regs for the function
627 * MAKE_NOP - Stop tracing the function
628 */
629enum {
630 FTRACE_UPDATE_IGNORE,
631 FTRACE_UPDATE_MAKE_CALL,
632 FTRACE_UPDATE_MODIFY_CALL,
633 FTRACE_UPDATE_MAKE_NOP,
634};
635
636enum {
637 FTRACE_ITER_FILTER = (1 << 0),
638 FTRACE_ITER_NOTRACE = (1 << 1),
639 FTRACE_ITER_PRINTALL = (1 << 2),
640 FTRACE_ITER_DO_PROBES = (1 << 3),
641 FTRACE_ITER_PROBE = (1 << 4),
642 FTRACE_ITER_MOD = (1 << 5),
643 FTRACE_ITER_ENABLED = (1 << 6),
644 FTRACE_ITER_TOUCHED = (1 << 7),
645 FTRACE_ITER_ADDRS = (1 << 8),
646};
647
648void arch_ftrace_update_code(int command);
649void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
650void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
651void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
652
653struct ftrace_rec_iter;
654
655struct ftrace_rec_iter *ftrace_rec_iter_start(void);
656struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
657struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
658
659#define for_ftrace_rec_iter(iter) \
660 for (iter = ftrace_rec_iter_start(); \
661 iter; \
662 iter = ftrace_rec_iter_next(iter))
663
664
665int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
666int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
667void ftrace_run_stop_machine(int command);
668unsigned long ftrace_location(unsigned long ip);
669unsigned long ftrace_location_range(unsigned long start, unsigned long end);
670unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
671unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
672
673extern ftrace_func_t ftrace_trace_function;
674
675int ftrace_regex_open(struct ftrace_ops *ops, int flag,
676 struct inode *inode, struct file *file);
677ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
678 size_t cnt, loff_t *ppos);
679ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
680 size_t cnt, loff_t *ppos);
681int ftrace_regex_release(struct inode *inode, struct file *file);
682
683void __init
684ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
685
686/* defined in arch */
687extern int ftrace_dyn_arch_init(void);
688extern void ftrace_replace_code(int enable);
689extern int ftrace_update_ftrace_func(ftrace_func_t func);
690extern void ftrace_caller(void);
691extern void ftrace_regs_caller(void);
692extern void ftrace_call(void);
693extern void ftrace_regs_call(void);
694extern void mcount_call(void);
695
696void ftrace_modify_all_code(int command);
697
698#ifndef FTRACE_ADDR
699#define FTRACE_ADDR ((unsigned long)ftrace_caller)
700#endif
701
702#ifndef FTRACE_GRAPH_ADDR
703#define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
704#endif
705
706#ifndef FTRACE_REGS_ADDR
707#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
708# define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
709#else
710# define FTRACE_REGS_ADDR FTRACE_ADDR
711#endif
712#endif
713
714/*
715 * If an arch would like functions that are only traced
716 * by the function graph tracer to jump directly to its own
717 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
718 * to be that address to jump to.
719 */
720#ifndef FTRACE_GRAPH_TRAMP_ADDR
721#define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
722#endif
723
724#ifdef CONFIG_FUNCTION_GRAPH_TRACER
725extern void ftrace_graph_caller(void);
726extern int ftrace_enable_ftrace_graph_caller(void);
727extern int ftrace_disable_ftrace_graph_caller(void);
728#else
729static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
730static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
731#endif
732
733/**
734 * ftrace_make_nop - convert code into nop
735 * @mod: module structure if called by module load initialization
736 * @rec: the call site record (e.g. mcount/fentry)
737 * @addr: the address that the call site should be calling
738 *
739 * This is a very sensitive operation and great care needs
740 * to be taken by the arch. The operation should carefully
741 * read the location, check to see if what is read is indeed
742 * what we expect it to be, and then on success of the compare,
743 * it should write to the location.
744 *
745 * The code segment at @rec->ip should be a caller to @addr
746 *
747 * Return must be:
748 * 0 on success
749 * -EFAULT on error reading the location
750 * -EINVAL on a failed compare of the contents
751 * -EPERM on error writing to the location
752 * Any other value will be considered a failure.
753 */
754extern int ftrace_make_nop(struct module *mod,
755 struct dyn_ftrace *rec, unsigned long addr);
756
757/**
758 * ftrace_need_init_nop - return whether nop call sites should be initialized
759 *
760 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't
761 * need to call ftrace_init_nop() if the code is built with that flag.
762 * Architectures where this is not always the case may define their own
763 * condition.
764 *
765 * Return must be:
766 * 0 if ftrace_init_nop() should be called
767 * Nonzero if ftrace_init_nop() should not be called
768 */
769
770#ifndef ftrace_need_init_nop
771#define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT))
772#endif
773
774/**
775 * ftrace_init_nop - initialize a nop call site
776 * @mod: module structure if called by module load initialization
777 * @rec: the call site record (e.g. mcount/fentry)
778 *
779 * This is a very sensitive operation and great care needs
780 * to be taken by the arch. The operation should carefully
781 * read the location, check to see if what is read is indeed
782 * what we expect it to be, and then on success of the compare,
783 * it should write to the location.
784 *
785 * The code segment at @rec->ip should contain the contents created by
786 * the compiler
787 *
788 * Return must be:
789 * 0 on success
790 * -EFAULT on error reading the location
791 * -EINVAL on a failed compare of the contents
792 * -EPERM on error writing to the location
793 * Any other value will be considered a failure.
794 */
795#ifndef ftrace_init_nop
796static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
797{
798 return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
799}
800#endif
801
802/**
803 * ftrace_make_call - convert a nop call site into a call to addr
804 * @rec: the call site record (e.g. mcount/fentry)
805 * @addr: the address that the call site should call
806 *
807 * This is a very sensitive operation and great care needs
808 * to be taken by the arch. The operation should carefully
809 * read the location, check to see if what is read is indeed
810 * what we expect it to be, and then on success of the compare,
811 * it should write to the location.
812 *
813 * The code segment at @rec->ip should be a nop
814 *
815 * Return must be:
816 * 0 on success
817 * -EFAULT on error reading the location
818 * -EINVAL on a failed compare of the contents
819 * -EPERM on error writing to the location
820 * Any other value will be considered a failure.
821 */
822extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
823
824#if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \
825 defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS)
826/**
827 * ftrace_modify_call - convert from one addr to another (no nop)
828 * @rec: the call site record (e.g. mcount/fentry)
829 * @old_addr: the address expected to be currently called to
830 * @addr: the address to change to
831 *
832 * This is a very sensitive operation and great care needs
833 * to be taken by the arch. The operation should carefully
834 * read the location, check to see if what is read is indeed
835 * what we expect it to be, and then on success of the compare,
836 * it should write to the location.
837 *
838 * When using call ops, this is called when the associated ops change, even
839 * when (addr == old_addr).
840 *
841 * The code segment at @rec->ip should be a caller to @old_addr
842 *
843 * Return must be:
844 * 0 on success
845 * -EFAULT on error reading the location
846 * -EINVAL on a failed compare of the contents
847 * -EPERM on error writing to the location
848 * Any other value will be considered a failure.
849 */
850extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
851 unsigned long addr);
852#else
853/* Should never be called */
854static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
855 unsigned long addr)
856{
857 return -EINVAL;
858}
859#endif
860
861extern int skip_trace(unsigned long ip);
862extern void ftrace_module_init(struct module *mod);
863extern void ftrace_module_enable(struct module *mod);
864extern void ftrace_release_mod(struct module *mod);
865#else /* CONFIG_DYNAMIC_FTRACE */
866static inline int skip_trace(unsigned long ip) { return 0; }
867static inline void ftrace_module_init(struct module *mod) { }
868static inline void ftrace_module_enable(struct module *mod) { }
869static inline void ftrace_release_mod(struct module *mod) { }
870static inline int ftrace_text_reserved(const void *start, const void *end)
871{
872 return 0;
873}
874static inline unsigned long ftrace_location(unsigned long ip)
875{
876 return 0;
877}
878
879/*
880 * Again users of functions that have ftrace_ops may not
881 * have them defined when ftrace is not enabled, but these
882 * functions may still be called. Use a macro instead of inline.
883 */
884#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
885#define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
886#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
887#define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; })
888#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
889#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
890#define ftrace_free_filter(ops) do { } while (0)
891#define ftrace_ops_set_global_filter(ops) do { } while (0)
892
893static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
894 size_t cnt, loff_t *ppos) { return -ENODEV; }
895static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
896 size_t cnt, loff_t *ppos) { return -ENODEV; }
897static inline int
898ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
899
900static inline bool is_ftrace_trampoline(unsigned long addr)
901{
902 return false;
903}
904#endif /* CONFIG_DYNAMIC_FTRACE */
905
906#ifdef CONFIG_FUNCTION_GRAPH_TRACER
907#ifndef ftrace_graph_func
908#define ftrace_graph_func ftrace_stub
909#define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB
910#else
911#define FTRACE_OPS_GRAPH_STUB 0
912#endif
913#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
914
915/* totally disable ftrace - can not re-enable after this */
916void ftrace_kill(void);
917
918static inline void tracer_disable(void)
919{
920#ifdef CONFIG_FUNCTION_TRACER
921 ftrace_enabled = 0;
922#endif
923}
924
925/*
926 * Ftrace disable/restore without lock. Some synchronization mechanism
927 * must be used to prevent ftrace_enabled to be changed between
928 * disable/restore.
929 */
930static inline int __ftrace_enabled_save(void)
931{
932#ifdef CONFIG_FUNCTION_TRACER
933 int saved_ftrace_enabled = ftrace_enabled;
934 ftrace_enabled = 0;
935 return saved_ftrace_enabled;
936#else
937 return 0;
938#endif
939}
940
941static inline void __ftrace_enabled_restore(int enabled)
942{
943#ifdef CONFIG_FUNCTION_TRACER
944 ftrace_enabled = enabled;
945#endif
946}
947
948/* All archs should have this, but we define it for consistency */
949#ifndef ftrace_return_address0
950# define ftrace_return_address0 __builtin_return_address(0)
951#endif
952
953/* Archs may use other ways for ADDR1 and beyond */
954#ifndef ftrace_return_address
955# ifdef CONFIG_FRAME_POINTER
956# define ftrace_return_address(n) __builtin_return_address(n)
957# else
958# define ftrace_return_address(n) 0UL
959# endif
960#endif
961
962#define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
963#define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
964#define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
965#define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
966#define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
967#define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
968#define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
969
970static __always_inline unsigned long get_lock_parent_ip(void)
971{
972 unsigned long addr = CALLER_ADDR0;
973
974 if (!in_lock_functions(addr))
975 return addr;
976 addr = CALLER_ADDR1;
977 if (!in_lock_functions(addr))
978 return addr;
979 return CALLER_ADDR2;
980}
981
982#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
983 extern void trace_preempt_on(unsigned long a0, unsigned long a1);
984 extern void trace_preempt_off(unsigned long a0, unsigned long a1);
985#else
986/*
987 * Use defines instead of static inlines because some arches will make code out
988 * of the CALLER_ADDR, when we really want these to be a real nop.
989 */
990# define trace_preempt_on(a0, a1) do { } while (0)
991# define trace_preempt_off(a0, a1) do { } while (0)
992#endif
993
994#ifdef CONFIG_FTRACE_MCOUNT_RECORD
995extern void ftrace_init(void);
996#ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
997#define FTRACE_CALLSITE_SECTION "__patchable_function_entries"
998#else
999#define FTRACE_CALLSITE_SECTION "__mcount_loc"
1000#endif
1001#else
1002static inline void ftrace_init(void) { }
1003#endif
1004
1005/*
1006 * Structure that defines an entry function trace.
1007 * It's already packed but the attribute "packed" is needed
1008 * to remove extra padding at the end.
1009 */
1010struct ftrace_graph_ent {
1011 unsigned long func; /* Current function */
1012 int depth;
1013} __packed;
1014
1015/*
1016 * Structure that defines a return function trace.
1017 * It's already packed but the attribute "packed" is needed
1018 * to remove extra padding at the end.
1019 */
1020struct ftrace_graph_ret {
1021 unsigned long func; /* Current function */
1022#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
1023 unsigned long retval;
1024#endif
1025 int depth;
1026 /* Number of functions that overran the depth limit for current task */
1027 unsigned int overrun;
1028 unsigned long long calltime;
1029 unsigned long long rettime;
1030} __packed;
1031
1032/* Type of the callback handlers for tracing function graph*/
1033typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
1034typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
1035
1036extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
1037
1038#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1039
1040struct fgraph_ops {
1041 trace_func_graph_ent_t entryfunc;
1042 trace_func_graph_ret_t retfunc;
1043};
1044
1045/*
1046 * Stack of return addresses for functions
1047 * of a thread.
1048 * Used in struct thread_info
1049 */
1050struct ftrace_ret_stack {
1051 unsigned long ret;
1052 unsigned long func;
1053 unsigned long long calltime;
1054#ifdef CONFIG_FUNCTION_PROFILER
1055 unsigned long long subtime;
1056#endif
1057#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
1058 unsigned long fp;
1059#endif
1060#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
1061 unsigned long *retp;
1062#endif
1063};
1064
1065/*
1066 * Primary handler of a function return.
1067 * It relays on ftrace_return_to_handler.
1068 * Defined in entry_32/64.S
1069 */
1070extern void return_to_handler(void);
1071
1072extern int
1073function_graph_enter(unsigned long ret, unsigned long func,
1074 unsigned long frame_pointer, unsigned long *retp);
1075
1076struct ftrace_ret_stack *
1077ftrace_graph_get_ret_stack(struct task_struct *task, int idx);
1078
1079unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
1080 unsigned long ret, unsigned long *retp);
1081
1082/*
1083 * Sometimes we don't want to trace a function with the function
1084 * graph tracer but we want them to keep traced by the usual function
1085 * tracer if the function graph tracer is not configured.
1086 */
1087#define __notrace_funcgraph notrace
1088
1089#define FTRACE_RETFUNC_DEPTH 50
1090#define FTRACE_RETSTACK_ALLOC_SIZE 32
1091
1092extern int register_ftrace_graph(struct fgraph_ops *ops);
1093extern void unregister_ftrace_graph(struct fgraph_ops *ops);
1094
1095/**
1096 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
1097 *
1098 * ftrace_graph_stop() is called when a severe error is detected in
1099 * the function graph tracing. This function is called by the critical
1100 * paths of function graph to keep those paths from doing any more harm.
1101 */
1102DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph);
1103
1104static inline bool ftrace_graph_is_dead(void)
1105{
1106 return static_branch_unlikely(&kill_ftrace_graph);
1107}
1108
1109extern void ftrace_graph_stop(void);
1110
1111/* The current handlers in use */
1112extern trace_func_graph_ret_t ftrace_graph_return;
1113extern trace_func_graph_ent_t ftrace_graph_entry;
1114
1115extern void ftrace_graph_init_task(struct task_struct *t);
1116extern void ftrace_graph_exit_task(struct task_struct *t);
1117extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
1118
1119static inline void pause_graph_tracing(void)
1120{
1121 atomic_inc(v: &current->tracing_graph_pause);
1122}
1123
1124static inline void unpause_graph_tracing(void)
1125{
1126 atomic_dec(v: &current->tracing_graph_pause);
1127}
1128#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
1129
1130#define __notrace_funcgraph
1131
1132static inline void ftrace_graph_init_task(struct task_struct *t) { }
1133static inline void ftrace_graph_exit_task(struct task_struct *t) { }
1134static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
1135
1136/* Define as macros as fgraph_ops may not be defined */
1137#define register_ftrace_graph(ops) ({ -1; })
1138#define unregister_ftrace_graph(ops) do { } while (0)
1139
1140static inline unsigned long
1141ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
1142 unsigned long *retp)
1143{
1144 return ret;
1145}
1146
1147static inline void pause_graph_tracing(void) { }
1148static inline void unpause_graph_tracing(void) { }
1149#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1150
1151#ifdef CONFIG_TRACING
1152enum ftrace_dump_mode;
1153
1154extern enum ftrace_dump_mode ftrace_dump_on_oops;
1155extern int tracepoint_printk;
1156
1157extern void disable_trace_on_warning(void);
1158extern int __disable_trace_on_warning;
1159
1160int tracepoint_printk_sysctl(struct ctl_table *table, int write,
1161 void *buffer, size_t *lenp, loff_t *ppos);
1162
1163#else /* CONFIG_TRACING */
1164static inline void disable_trace_on_warning(void) { }
1165#endif /* CONFIG_TRACING */
1166
1167#ifdef CONFIG_FTRACE_SYSCALLS
1168
1169unsigned long arch_syscall_addr(int nr);
1170
1171#endif /* CONFIG_FTRACE_SYSCALLS */
1172
1173#endif /* _LINUX_FTRACE_H */
1174

source code of linux/include/linux/ftrace.h