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
35 extern void ftrace_boot_snapshot(void);
36 #else
ftrace_boot_snapshot(void)37 static inline void ftrace_boot_snapshot(void) { }
38 #endif
39
40 struct ftrace_ops;
41 struct ftrace_regs;
42 struct dyn_ftrace;
43
44 char *arch_ftrace_match_adjust(char *str, const char *search);
45
46 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FREGS
47 unsigned long ftrace_return_to_handler(struct ftrace_regs *fregs);
48 #else
49 unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
50 #endif
51
52 #ifdef CONFIG_FUNCTION_TRACER
53 /*
54 * If the arch's mcount caller does not support all of ftrace's
55 * features, then it must call an indirect function that
56 * does. Or at least does enough to prevent any unwelcome side effects.
57 *
58 * Also define the function prototype that these architectures use
59 * to call the ftrace_ops_list_func().
60 */
61 #if !ARCH_SUPPORTS_FTRACE_OPS
62 # define FTRACE_FORCE_LIST_FUNC 1
63 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
64 #else
65 # define FTRACE_FORCE_LIST_FUNC 0
66 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
67 struct ftrace_ops *op, struct ftrace_regs *fregs);
68 #endif
69 extern const struct ftrace_ops ftrace_nop_ops;
70 extern const struct ftrace_ops ftrace_list_ops;
71 struct ftrace_ops *ftrace_find_unique_ops(struct dyn_ftrace *rec);
72 #endif /* CONFIG_FUNCTION_TRACER */
73
74 /* Main tracing buffer and events set up */
75 #ifdef CONFIG_TRACING
76 void trace_init(void);
77 void early_trace_init(void);
78 #else
trace_init(void)79 static inline void trace_init(void) { }
early_trace_init(void)80 static inline void early_trace_init(void) { }
81 #endif
82
83 struct module;
84 struct ftrace_hash;
85
86 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
87 defined(CONFIG_DYNAMIC_FTRACE)
88 int
89 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
90 unsigned long *off, char **modname, char *sym);
91 #else
92 static inline int
ftrace_mod_address_lookup(unsigned long addr,unsigned long * size,unsigned long * off,char ** modname,char * sym)93 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
94 unsigned long *off, char **modname, char *sym)
95 {
96 return 0;
97 }
98 #endif
99
100 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
101 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
102 char *type, char *name,
103 char *module_name, int *exported);
104 #else
ftrace_mod_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * name,char * module_name,int * exported)105 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
106 char *type, char *name,
107 char *module_name, int *exported)
108 {
109 return -1;
110 }
111 #endif
112
113 #ifdef CONFIG_FUNCTION_TRACER
114
115 #include <linux/ftrace_regs.h>
116
117 extern int ftrace_enabled;
118
119 /**
120 * ftrace_regs - ftrace partial/optimal register set
121 *
122 * ftrace_regs represents a group of registers which is used at the
123 * function entry and exit. There are three types of registers.
124 *
125 * - Registers for passing the parameters to callee, including the stack
126 * pointer. (e.g. rcx, rdx, rdi, rsi, r8, r9 and rsp on x86_64)
127 * - Registers for passing the return values to caller.
128 * (e.g. rax and rdx on x86_64)
129 * - Registers for hooking the function call and return including the
130 * frame pointer (the frame pointer is architecture/config dependent)
131 * (e.g. rip, rbp and rsp for x86_64)
132 *
133 * Also, architecture dependent fields can be used for internal process.
134 * (e.g. orig_ax on x86_64)
135 *
136 * Basically, ftrace_regs stores the registers related to the context.
137 * On function entry, registers for function parameters and hooking the
138 * function call are stored, and on function exit, registers for function
139 * return value and frame pointers are stored.
140 *
141 * And also, it dpends on the context that which registers are restored
142 * from the ftrace_regs.
143 * On the function entry, those registers will be restored except for
144 * the stack pointer, so that user can change the function parameters
145 * and instruction pointer (e.g. live patching.)
146 * On the function exit, only registers which is used for return values
147 * are restored.
148 *
149 * NOTE: user *must not* access regs directly, only do it via APIs, because
150 * the member can be changed according to the architecture.
151 * This is why the structure is empty here, so that nothing accesses
152 * the ftrace_regs directly.
153 */
154 struct ftrace_regs {
155 /* Nothing to see here, use the accessor functions! */
156 };
157
158 #define ftrace_regs_size() sizeof(struct __arch_ftrace_regs)
159
160 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
161 /*
162 * Architectures that define HAVE_DYNAMIC_FTRACE_WITH_ARGS must define their own
163 * arch_ftrace_get_regs() where it only returns pt_regs *if* it is fully
164 * populated. It should return NULL otherwise.
165 */
arch_ftrace_get_regs(struct ftrace_regs * fregs)166 static inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
167 {
168 return &arch_ftrace_regs(fregs)->regs;
169 }
170
171 /*
172 * ftrace_regs_set_instruction_pointer() is to be defined by the architecture
173 * if to allow setting of the instruction pointer from the ftrace_regs when
174 * HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports live kernel patching.
175 */
176 #define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0)
177 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
178
179 #ifdef CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS
180
181 static_assert(sizeof(struct pt_regs) == ftrace_regs_size());
182
183 #endif /* CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */
184
ftrace_get_regs(struct ftrace_regs * fregs)185 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
186 {
187 if (!fregs)
188 return NULL;
189
190 return arch_ftrace_get_regs(fregs);
191 }
192
193 #if !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS) || \
194 defined(CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS)
195
196 static __always_inline struct pt_regs *
ftrace_partial_regs(struct ftrace_regs * fregs,struct pt_regs * regs)197 ftrace_partial_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
198 {
199 /*
200 * If CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS=y, ftrace_regs memory
201 * layout is including pt_regs. So always returns that address.
202 * Since arch_ftrace_get_regs() will check some members and may return
203 * NULL, we can not use it.
204 */
205 return &arch_ftrace_regs(fregs)->regs;
206 }
207
208 #endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS || CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */
209
210 #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
211
212 /*
213 * Please define arch dependent pt_regs which compatible to the
214 * perf_arch_fetch_caller_regs() but based on ftrace_regs.
215 * This requires
216 * - user_mode(_regs) returns false (always kernel mode).
217 * - able to use the _regs for stack trace.
218 */
219 #ifndef arch_ftrace_fill_perf_regs
220 /* As same as perf_arch_fetch_caller_regs(), do nothing by default */
221 #define arch_ftrace_fill_perf_regs(fregs, _regs) do {} while (0)
222 #endif
223
224 static __always_inline struct pt_regs *
ftrace_fill_perf_regs(struct ftrace_regs * fregs,struct pt_regs * regs)225 ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
226 {
227 arch_ftrace_fill_perf_regs(fregs, regs);
228 return regs;
229 }
230
231 #else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
232
233 static __always_inline struct pt_regs *
ftrace_fill_perf_regs(struct ftrace_regs * fregs,struct pt_regs * regs)234 ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
235 {
236 return &arch_ftrace_regs(fregs)->regs;
237 }
238
239 #endif
240
241 /*
242 * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs.
243 * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs.
244 */
ftrace_regs_has_args(struct ftrace_regs * fregs)245 static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
246 {
247 if (IS_ENABLED(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS))
248 return true;
249
250 return ftrace_get_regs(fregs) != NULL;
251 }
252
253 #ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
254 static __always_inline unsigned long
ftrace_regs_get_kernel_stack_nth(struct ftrace_regs * fregs,unsigned int nth)255 ftrace_regs_get_kernel_stack_nth(struct ftrace_regs *fregs, unsigned int nth)
256 {
257 unsigned long *stackp;
258
259 stackp = (unsigned long *)ftrace_regs_get_stack_pointer(fregs);
260 if (((unsigned long)(stackp + nth) & ~(THREAD_SIZE - 1)) ==
261 ((unsigned long)stackp & ~(THREAD_SIZE - 1)))
262 return *(stackp + nth);
263
264 return 0;
265 }
266 #else /* !CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */
267 #define ftrace_regs_get_kernel_stack_nth(fregs, nth) (0L)
268 #endif /* CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */
269
270 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
271 struct ftrace_ops *op, struct ftrace_regs *fregs);
272
273 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
274
275 /*
276 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
277 * set in the flags member.
278 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
279 * IPMODIFY are a kind of attribute flags which can be set only before
280 * registering the ftrace_ops, and can not be modified while registered.
281 * Changing those attribute flags after registering ftrace_ops will
282 * cause unexpected results.
283 *
284 * ENABLED - set/unset when ftrace_ops is registered/unregistered
285 * DYNAMIC - set when ftrace_ops is registered to denote dynamically
286 * allocated ftrace_ops which need special care
287 * SAVE_REGS - The ftrace_ops wants regs saved at each function called
288 * and passed to the callback. If this flag is set, but the
289 * architecture does not support passing regs
290 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
291 * ftrace_ops will fail to register, unless the next flag
292 * is set.
293 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
294 * handler can handle an arch that does not save regs
295 * (the handler tests if regs == NULL), then it can set
296 * this flag instead. It will not fail registering the ftrace_ops
297 * but, the regs field will be NULL if the arch does not support
298 * passing regs to the handler.
299 * Note, if this flag is set, the SAVE_REGS flag will automatically
300 * get set upon registering the ftrace_ops, if the arch supports it.
301 * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
302 * that the call back needs recursion protection. If it does
303 * not set this, then the ftrace infrastructure will assume
304 * that the callback can handle recursion on its own.
305 * STUB - The ftrace_ops is just a place holder.
306 * INITIALIZED - The ftrace_ops has already been initialized (first use time
307 * register_ftrace_function() is called, it will initialized the ops)
308 * DELETED - The ops are being deleted, do not let them be registered again.
309 * ADDING - The ops is in the process of being added.
310 * REMOVING - The ops is in the process of being removed.
311 * MODIFYING - The ops is in the process of changing its filter functions.
312 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
313 * The arch specific code sets this flag when it allocated a
314 * trampoline. This lets the arch know that it can update the
315 * trampoline in case the callback function changes.
316 * The ftrace_ops trampoline can be set by the ftrace users, and
317 * in such cases the arch must not modify it. Only the arch ftrace
318 * core code should set this flag.
319 * IPMODIFY - The ops can modify the IP register. This can only be set with
320 * SAVE_REGS. If another ops with this flag set is already registered
321 * for any of the functions that this ops will be registered for, then
322 * this ops will fail to register or set_filter_ip.
323 * PID - Is affected by set_ftrace_pid (allows filtering on those pids)
324 * RCU - Set when the ops can only be called when RCU is watching.
325 * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
326 * PERMANENT - Set when the ops is permanent and should not be affected by
327 * ftrace_enabled.
328 * DIRECT - Used by the direct ftrace_ops helper for direct functions
329 * (internal ftrace only, should not be used by others)
330 * SUBOP - Is controlled by another op in field managed.
331 */
332 enum {
333 FTRACE_OPS_FL_ENABLED = BIT(0),
334 FTRACE_OPS_FL_DYNAMIC = BIT(1),
335 FTRACE_OPS_FL_SAVE_REGS = BIT(2),
336 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3),
337 FTRACE_OPS_FL_RECURSION = BIT(4),
338 FTRACE_OPS_FL_STUB = BIT(5),
339 FTRACE_OPS_FL_INITIALIZED = BIT(6),
340 FTRACE_OPS_FL_DELETED = BIT(7),
341 FTRACE_OPS_FL_ADDING = BIT(8),
342 FTRACE_OPS_FL_REMOVING = BIT(9),
343 FTRACE_OPS_FL_MODIFYING = BIT(10),
344 FTRACE_OPS_FL_ALLOC_TRAMP = BIT(11),
345 FTRACE_OPS_FL_IPMODIFY = BIT(12),
346 FTRACE_OPS_FL_PID = BIT(13),
347 FTRACE_OPS_FL_RCU = BIT(14),
348 FTRACE_OPS_FL_TRACE_ARRAY = BIT(15),
349 FTRACE_OPS_FL_PERMANENT = BIT(16),
350 FTRACE_OPS_FL_DIRECT = BIT(17),
351 FTRACE_OPS_FL_SUBOP = BIT(18),
352 };
353
354 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
355 #define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS
356 #else
357 #define FTRACE_OPS_FL_SAVE_ARGS 0
358 #endif
359
360 /*
361 * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes
362 * to a ftrace_ops. Note, the requests may fail.
363 *
364 * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same
365 * function as an ops with IPMODIFY. Called
366 * when the DIRECT ops is being registered.
367 * This is called with both direct_mutex and
368 * ftrace_lock are locked.
369 *
370 * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same
371 * function as an ops with IPMODIFY. Called
372 * when the other ops (the one with IPMODIFY)
373 * is being registered.
374 * This is called with direct_mutex locked.
375 *
376 * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same
377 * function as an ops with IPMODIFY. Called
378 * when the other ops (the one with IPMODIFY)
379 * is being unregistered.
380 * This is called with direct_mutex locked.
381 */
382 enum ftrace_ops_cmd {
383 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF,
384 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER,
385 FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER,
386 };
387
388 /*
389 * For most ftrace_ops_cmd,
390 * Returns:
391 * 0 - Success.
392 * Negative on failure. The return value is dependent on the
393 * callback.
394 */
395 typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd);
396
397 #ifdef CONFIG_DYNAMIC_FTRACE
398 /* The hash used to know what functions callbacks trace */
399 struct ftrace_ops_hash {
400 struct ftrace_hash __rcu *notrace_hash;
401 struct ftrace_hash __rcu *filter_hash;
402 struct mutex regex_lock;
403 };
404
405 void ftrace_free_init_mem(void);
406 void ftrace_free_mem(struct module *mod, void *start, void *end);
407 #else
ftrace_free_init_mem(void)408 static inline void ftrace_free_init_mem(void)
409 {
410 ftrace_boot_snapshot();
411 }
ftrace_free_mem(struct module * mod,void * start,void * end)412 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
413 #endif
414
415 /*
416 * Note, ftrace_ops can be referenced outside of RCU protection, unless
417 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
418 * core data, the unregistering of it will perform a scheduling on all CPUs
419 * to make sure that there are no more users. Depending on the load of the
420 * system that may take a bit of time.
421 *
422 * Any private data added must also take care not to be freed and if private
423 * data is added to a ftrace_ops that is in core code, the user of the
424 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
425 */
426 struct ftrace_ops {
427 ftrace_func_t func;
428 struct ftrace_ops __rcu *next;
429 unsigned long flags;
430 void *private;
431 ftrace_func_t saved_func;
432 #ifdef CONFIG_DYNAMIC_FTRACE
433 struct ftrace_ops_hash local_hash;
434 struct ftrace_ops_hash *func_hash;
435 struct ftrace_ops_hash old_hash;
436 unsigned long trampoline;
437 unsigned long trampoline_size;
438 struct list_head list;
439 struct list_head subop_list;
440 ftrace_ops_func_t ops_func;
441 struct ftrace_ops *managed;
442 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
443 unsigned long direct_call;
444 #endif
445 #endif
446 };
447
448 extern struct ftrace_ops __rcu *ftrace_ops_list;
449 extern struct ftrace_ops ftrace_list_end;
450
451 /*
452 * Traverse the ftrace_ops_list, invoking all entries. The reason that we
453 * can use rcu_dereference_raw_check() is that elements removed from this list
454 * are simply leaked, so there is no need to interact with a grace-period
455 * mechanism. The rcu_dereference_raw_check() calls are needed to handle
456 * concurrent insertions into the ftrace_ops_list.
457 *
458 * Silly Alpha and silly pointer-speculation compiler optimizations!
459 */
460 #define do_for_each_ftrace_op(op, list) \
461 op = rcu_dereference_raw_check(list); \
462 do
463
464 /*
465 * Optimized for just a single item in the list (as that is the normal case).
466 */
467 #define while_for_each_ftrace_op(op) \
468 while (likely(op = rcu_dereference_raw_check((op)->next)) && \
469 unlikely((op) != &ftrace_list_end))
470
471 /*
472 * Type of the current tracing.
473 */
474 enum ftrace_tracing_type_t {
475 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
476 FTRACE_TYPE_RETURN, /* Hook the return of the function */
477 };
478
479 /* Current tracing type, default is FTRACE_TYPE_ENTER */
480 extern enum ftrace_tracing_type_t ftrace_tracing_type;
481
482 /*
483 * The ftrace_ops must be a static and should also
484 * be read_mostly. These functions do modify read_mostly variables
485 * so use them sparely. Never free an ftrace_op or modify the
486 * next pointer after it has been registered. Even after unregistering
487 * it, the next pointer may still be used internally.
488 */
489 int register_ftrace_function(struct ftrace_ops *ops);
490 int unregister_ftrace_function(struct ftrace_ops *ops);
491
492 extern void ftrace_stub(unsigned long a0, unsigned long a1,
493 struct ftrace_ops *op, struct ftrace_regs *fregs);
494
495
496 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs);
497 #else /* !CONFIG_FUNCTION_TRACER */
498 /*
499 * (un)register_ftrace_function must be a macro since the ops parameter
500 * must not be evaluated.
501 */
502 #define register_ftrace_function(ops) ({ 0; })
503 #define unregister_ftrace_function(ops) ({ 0; })
ftrace_kill(void)504 static inline void ftrace_kill(void) { }
ftrace_free_init_mem(void)505 static inline void ftrace_free_init_mem(void) { }
ftrace_free_mem(struct module * mod,void * start,void * end)506 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
ftrace_lookup_symbols(const char ** sorted_syms,size_t cnt,unsigned long * addrs)507 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
508 {
509 return -EOPNOTSUPP;
510 }
511 #endif /* CONFIG_FUNCTION_TRACER */
512
513 struct ftrace_func_entry {
514 struct hlist_node hlist;
515 unsigned long ip;
516 unsigned long direct; /* for direct lookup only */
517 };
518
519 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
520 unsigned long ftrace_find_rec_direct(unsigned long ip);
521 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
522 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
523 bool free_filters);
524 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
525 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr);
526
527 void ftrace_stub_direct_tramp(void);
528
529 #else
530 struct ftrace_ops;
ftrace_find_rec_direct(unsigned long ip)531 static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
532 {
533 return 0;
534 }
register_ftrace_direct(struct ftrace_ops * ops,unsigned long addr)535 static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
536 {
537 return -ENODEV;
538 }
unregister_ftrace_direct(struct ftrace_ops * ops,unsigned long addr,bool free_filters)539 static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
540 bool free_filters)
541 {
542 return -ENODEV;
543 }
modify_ftrace_direct(struct ftrace_ops * ops,unsigned long addr)544 static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
545 {
546 return -ENODEV;
547 }
modify_ftrace_direct_nolock(struct ftrace_ops * ops,unsigned long addr)548 static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
549 {
550 return -ENODEV;
551 }
552
553 /*
554 * This must be implemented by the architecture.
555 * It is the way the ftrace direct_ops helper, when called
556 * via ftrace (because there's other callbacks besides the
557 * direct call), can inform the architecture's trampoline that this
558 * routine has a direct caller, and what the caller is.
559 *
560 * For example, in x86, it returns the direct caller
561 * callback function via the regs->orig_ax parameter.
562 * Then in the ftrace trampoline, if this is set, it makes
563 * the return from the trampoline jump to the direct caller
564 * instead of going back to the function it just traced.
565 */
arch_ftrace_set_direct_caller(struct ftrace_regs * fregs,unsigned long addr)566 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
567 unsigned long addr) { }
568 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
569
570 #ifdef CONFIG_STACK_TRACER
571
572 extern int stack_tracer_enabled;
573
574 int stack_trace_sysctl(const struct ctl_table *table, int write, void *buffer,
575 size_t *lenp, loff_t *ppos);
576
577 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
578 DECLARE_PER_CPU(int, disable_stack_tracer);
579
580 /**
581 * stack_tracer_disable - temporarily disable the stack tracer
582 *
583 * There's a few locations (namely in RCU) where stack tracing
584 * cannot be executed. This function is used to disable stack
585 * tracing during those critical sections.
586 *
587 * This function must be called with preemption or interrupts
588 * disabled and stack_tracer_enable() must be called shortly after
589 * while preemption or interrupts are still disabled.
590 */
stack_tracer_disable(void)591 static inline void stack_tracer_disable(void)
592 {
593 /* Preemption or interrupts must be disabled */
594 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
595 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
596 this_cpu_inc(disable_stack_tracer);
597 }
598
599 /**
600 * stack_tracer_enable - re-enable the stack tracer
601 *
602 * After stack_tracer_disable() is called, stack_tracer_enable()
603 * must be called shortly afterward.
604 */
stack_tracer_enable(void)605 static inline void stack_tracer_enable(void)
606 {
607 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
608 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
609 this_cpu_dec(disable_stack_tracer);
610 }
611 #else
stack_tracer_disable(void)612 static inline void stack_tracer_disable(void) { }
stack_tracer_enable(void)613 static inline void stack_tracer_enable(void) { }
614 #endif
615
616 enum {
617 FTRACE_UPDATE_CALLS = (1 << 0),
618 FTRACE_DISABLE_CALLS = (1 << 1),
619 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
620 FTRACE_START_FUNC_RET = (1 << 3),
621 FTRACE_STOP_FUNC_RET = (1 << 4),
622 FTRACE_MAY_SLEEP = (1 << 5),
623 };
624
625 /* Arches can override ftrace_get_symaddr() to convert fentry_ip to symaddr. */
626 #ifndef ftrace_get_symaddr
627 /**
628 * ftrace_get_symaddr - return the symbol address from fentry_ip
629 * @fentry_ip: the address of ftrace location
630 *
631 * Get the symbol address from @fentry_ip (fast path). If there is no fast
632 * search path, this returns 0.
633 * User may need to use kallsyms API to find the symbol address.
634 */
635 #define ftrace_get_symaddr(fentry_ip) (0)
636 #endif
637
638 #ifdef CONFIG_DYNAMIC_FTRACE
639
640 void ftrace_arch_code_modify_prepare(void);
641 void ftrace_arch_code_modify_post_process(void);
642
643 enum ftrace_bug_type {
644 FTRACE_BUG_UNKNOWN,
645 FTRACE_BUG_INIT,
646 FTRACE_BUG_NOP,
647 FTRACE_BUG_CALL,
648 FTRACE_BUG_UPDATE,
649 };
650 extern enum ftrace_bug_type ftrace_bug_type;
651
652 /*
653 * Archs can set this to point to a variable that holds the value that was
654 * expected at the call site before calling ftrace_bug().
655 */
656 extern const void *ftrace_expected;
657
658 void ftrace_bug(int err, struct dyn_ftrace *rec);
659
660 struct seq_file;
661
662 extern int ftrace_text_reserved(const void *start, const void *end);
663
664 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
665
666 bool is_ftrace_trampoline(unsigned long addr);
667
668 /*
669 * The dyn_ftrace record's flags field is split into two parts.
670 * the first part which is '0-FTRACE_REF_MAX' is a counter of
671 * the number of callbacks that have registered the function that
672 * the dyn_ftrace descriptor represents.
673 *
674 * The second part is a mask:
675 * ENABLED - the function is being traced
676 * REGS - the record wants the function to save regs
677 * REGS_EN - the function is set up to save regs.
678 * IPMODIFY - the record allows for the IP address to be changed.
679 * DISABLED - the record is not ready to be touched yet
680 * DIRECT - there is a direct function to call
681 * CALL_OPS - the record can use callsite-specific ops
682 * CALL_OPS_EN - the function is set up to use callsite-specific ops
683 * TOUCHED - A callback was added since boot up
684 * MODIFIED - The function had IPMODIFY or DIRECT attached to it
685 *
686 * When a new ftrace_ops is registered and wants a function to save
687 * pt_regs, the rec->flags REGS is set. When the function has been
688 * set up to save regs, the REG_EN flag is set. Once a function
689 * starts saving regs it will do so until all ftrace_ops are removed
690 * from tracing that function.
691 */
692 enum {
693 FTRACE_FL_ENABLED = (1UL << 31),
694 FTRACE_FL_REGS = (1UL << 30),
695 FTRACE_FL_REGS_EN = (1UL << 29),
696 FTRACE_FL_TRAMP = (1UL << 28),
697 FTRACE_FL_TRAMP_EN = (1UL << 27),
698 FTRACE_FL_IPMODIFY = (1UL << 26),
699 FTRACE_FL_DISABLED = (1UL << 25),
700 FTRACE_FL_DIRECT = (1UL << 24),
701 FTRACE_FL_DIRECT_EN = (1UL << 23),
702 FTRACE_FL_CALL_OPS = (1UL << 22),
703 FTRACE_FL_CALL_OPS_EN = (1UL << 21),
704 FTRACE_FL_TOUCHED = (1UL << 20),
705 FTRACE_FL_MODIFIED = (1UL << 19),
706 };
707
708 #define FTRACE_REF_MAX_SHIFT 19
709 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
710
711 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX)
712
713 struct dyn_ftrace {
714 unsigned long ip; /* address of mcount call-site */
715 unsigned long flags;
716 struct dyn_arch_ftrace arch;
717 };
718
719 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
720 int remove, int reset);
721 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
722 unsigned int cnt, int remove, int reset);
723 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
724 int len, int reset);
725 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
726 int len, int reset);
727 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
728 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
729 void ftrace_free_filter(struct ftrace_ops *ops);
730 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
731
732 /*
733 * The FTRACE_UPDATE_* enum is used to pass information back
734 * from the ftrace_update_record() and ftrace_test_record()
735 * functions. These are called by the code update routines
736 * to find out what is to be done for a given function.
737 *
738 * IGNORE - The function is already what we want it to be
739 * MAKE_CALL - Start tracing the function
740 * MODIFY_CALL - Stop saving regs for the function
741 * MAKE_NOP - Stop tracing the function
742 */
743 enum {
744 FTRACE_UPDATE_IGNORE,
745 FTRACE_UPDATE_MAKE_CALL,
746 FTRACE_UPDATE_MODIFY_CALL,
747 FTRACE_UPDATE_MAKE_NOP,
748 };
749
750 enum {
751 FTRACE_ITER_FILTER = (1 << 0),
752 FTRACE_ITER_NOTRACE = (1 << 1),
753 FTRACE_ITER_PRINTALL = (1 << 2),
754 FTRACE_ITER_DO_PROBES = (1 << 3),
755 FTRACE_ITER_PROBE = (1 << 4),
756 FTRACE_ITER_MOD = (1 << 5),
757 FTRACE_ITER_ENABLED = (1 << 6),
758 FTRACE_ITER_TOUCHED = (1 << 7),
759 FTRACE_ITER_ADDRS = (1 << 8),
760 };
761
762 void arch_ftrace_update_code(int command);
763 void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
764 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
765 void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
766
767 struct ftrace_rec_iter;
768
769 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
770 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
771 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
772
773 #define for_ftrace_rec_iter(iter) \
774 for (iter = ftrace_rec_iter_start(); \
775 iter; \
776 iter = ftrace_rec_iter_next(iter))
777
778
779 int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
780 int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
781 void ftrace_run_stop_machine(int command);
782 unsigned long ftrace_location(unsigned long ip);
783 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
784 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
785 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
786
787 extern ftrace_func_t ftrace_trace_function;
788
789 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
790 struct inode *inode, struct file *file);
791 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
792 size_t cnt, loff_t *ppos);
793 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
794 size_t cnt, loff_t *ppos);
795 int ftrace_regex_release(struct inode *inode, struct file *file);
796
797 void __init
798 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
799
800 /* defined in arch */
801 extern int ftrace_dyn_arch_init(void);
802 extern void ftrace_replace_code(int enable);
803 extern int ftrace_update_ftrace_func(ftrace_func_t func);
804 extern void ftrace_caller(void);
805 extern void ftrace_regs_caller(void);
806 extern void ftrace_call(void);
807 extern void ftrace_regs_call(void);
808 extern void mcount_call(void);
809
810 void ftrace_modify_all_code(int command);
811
812 #ifndef FTRACE_ADDR
813 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
814 #endif
815
816 #ifndef FTRACE_GRAPH_ADDR
817 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
818 #endif
819
820 #ifndef FTRACE_REGS_ADDR
821 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
822 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
823 #else
824 # define FTRACE_REGS_ADDR FTRACE_ADDR
825 #endif
826 #endif
827
828 /*
829 * If an arch would like functions that are only traced
830 * by the function graph tracer to jump directly to its own
831 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
832 * to be that address to jump to.
833 */
834 #ifndef FTRACE_GRAPH_TRAMP_ADDR
835 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
836 #endif
837
838 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
839 extern void ftrace_graph_caller(void);
840 extern int ftrace_enable_ftrace_graph_caller(void);
841 extern int ftrace_disable_ftrace_graph_caller(void);
842 #else
ftrace_enable_ftrace_graph_caller(void)843 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
ftrace_disable_ftrace_graph_caller(void)844 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
845 #endif
846
847 /**
848 * ftrace_make_nop - convert code into nop
849 * @mod: module structure if called by module load initialization
850 * @rec: the call site record (e.g. mcount/fentry)
851 * @addr: the address that the call site should be calling
852 *
853 * This is a very sensitive operation and great care needs
854 * to be taken by the arch. The operation should carefully
855 * read the location, check to see if what is read is indeed
856 * what we expect it to be, and then on success of the compare,
857 * it should write to the location.
858 *
859 * The code segment at @rec->ip should be a caller to @addr
860 *
861 * Return must be:
862 * 0 on success
863 * -EFAULT on error reading the location
864 * -EINVAL on a failed compare of the contents
865 * -EPERM on error writing to the location
866 * Any other value will be considered a failure.
867 */
868 extern int ftrace_make_nop(struct module *mod,
869 struct dyn_ftrace *rec, unsigned long addr);
870
871 /**
872 * ftrace_need_init_nop - return whether nop call sites should be initialized
873 *
874 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't
875 * need to call ftrace_init_nop() if the code is built with that flag.
876 * Architectures where this is not always the case may define their own
877 * condition.
878 *
879 * Return must be:
880 * 0 if ftrace_init_nop() should be called
881 * Nonzero if ftrace_init_nop() should not be called
882 */
883
884 #ifndef ftrace_need_init_nop
885 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT))
886 #endif
887
888 /**
889 * ftrace_init_nop - initialize a nop call site
890 * @mod: module structure if called by module load initialization
891 * @rec: the call site record (e.g. mcount/fentry)
892 *
893 * This is a very sensitive operation and great care needs
894 * to be taken by the arch. The operation should carefully
895 * read the location, check to see if what is read is indeed
896 * what we expect it to be, and then on success of the compare,
897 * it should write to the location.
898 *
899 * The code segment at @rec->ip should contain the contents created by
900 * the compiler
901 *
902 * Return must be:
903 * 0 on success
904 * -EFAULT on error reading the location
905 * -EINVAL on a failed compare of the contents
906 * -EPERM on error writing to the location
907 * Any other value will be considered a failure.
908 */
909 #ifndef ftrace_init_nop
ftrace_init_nop(struct module * mod,struct dyn_ftrace * rec)910 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
911 {
912 return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
913 }
914 #endif
915
916 /**
917 * ftrace_make_call - convert a nop call site into a call to addr
918 * @rec: the call site record (e.g. mcount/fentry)
919 * @addr: the address that the call site should call
920 *
921 * This is a very sensitive operation and great care needs
922 * to be taken by the arch. The operation should carefully
923 * read the location, check to see if what is read is indeed
924 * what we expect it to be, and then on success of the compare,
925 * it should write to the location.
926 *
927 * The code segment at @rec->ip should be a nop
928 *
929 * Return must be:
930 * 0 on success
931 * -EFAULT on error reading the location
932 * -EINVAL on a failed compare of the contents
933 * -EPERM on error writing to the location
934 * Any other value will be considered a failure.
935 */
936 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
937
938 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \
939 defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) || \
940 defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS)
941 /**
942 * ftrace_modify_call - convert from one addr to another (no nop)
943 * @rec: the call site record (e.g. mcount/fentry)
944 * @old_addr: the address expected to be currently called to
945 * @addr: the address to change to
946 *
947 * This is a very sensitive operation and great care needs
948 * to be taken by the arch. The operation should carefully
949 * read the location, check to see if what is read is indeed
950 * what we expect it to be, and then on success of the compare,
951 * it should write to the location.
952 *
953 * When using call ops, this is called when the associated ops change, even
954 * when (addr == old_addr).
955 *
956 * The code segment at @rec->ip should be a caller to @old_addr
957 *
958 * Return must be:
959 * 0 on success
960 * -EFAULT on error reading the location
961 * -EINVAL on a failed compare of the contents
962 * -EPERM on error writing to the location
963 * Any other value will be considered a failure.
964 */
965 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
966 unsigned long addr);
967 #else
968 /* Should never be called */
ftrace_modify_call(struct dyn_ftrace * rec,unsigned long old_addr,unsigned long addr)969 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
970 unsigned long addr)
971 {
972 return -EINVAL;
973 }
974 #endif
975
976 extern int skip_trace(unsigned long ip);
977 extern void ftrace_module_init(struct module *mod);
978 extern void ftrace_module_enable(struct module *mod);
979 extern void ftrace_release_mod(struct module *mod);
980 #else /* CONFIG_DYNAMIC_FTRACE */
skip_trace(unsigned long ip)981 static inline int skip_trace(unsigned long ip) { return 0; }
ftrace_module_init(struct module * mod)982 static inline void ftrace_module_init(struct module *mod) { }
ftrace_module_enable(struct module * mod)983 static inline void ftrace_module_enable(struct module *mod) { }
ftrace_release_mod(struct module * mod)984 static inline void ftrace_release_mod(struct module *mod) { }
ftrace_text_reserved(const void * start,const void * end)985 static inline int ftrace_text_reserved(const void *start, const void *end)
986 {
987 return 0;
988 }
ftrace_location(unsigned long ip)989 static inline unsigned long ftrace_location(unsigned long ip)
990 {
991 return 0;
992 }
993
994 /*
995 * Again users of functions that have ftrace_ops may not
996 * have them defined when ftrace is not enabled, but these
997 * functions may still be called. Use a macro instead of inline.
998 */
999 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
1000 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
1001 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
1002 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; })
1003 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
1004 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
1005 #define ftrace_free_filter(ops) do { } while (0)
1006 #define ftrace_ops_set_global_filter(ops) do { } while (0)
1007
ftrace_filter_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)1008 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
1009 size_t cnt, loff_t *ppos) { return -ENODEV; }
ftrace_notrace_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)1010 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
1011 size_t cnt, loff_t *ppos) { return -ENODEV; }
1012 static inline int
ftrace_regex_release(struct inode * inode,struct file * file)1013 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
1014
is_ftrace_trampoline(unsigned long addr)1015 static inline bool is_ftrace_trampoline(unsigned long addr)
1016 {
1017 return false;
1018 }
1019 #endif /* CONFIG_DYNAMIC_FTRACE */
1020
1021 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1022 #ifndef ftrace_graph_func
1023 #define ftrace_graph_func ftrace_stub
1024 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB
1025 #else
1026 #define FTRACE_OPS_GRAPH_STUB 0
1027 #endif
1028 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1029
1030 /* totally disable ftrace - can not re-enable after this */
1031 void ftrace_kill(void);
1032
tracer_disable(void)1033 static inline void tracer_disable(void)
1034 {
1035 #ifdef CONFIG_FUNCTION_TRACER
1036 ftrace_enabled = 0;
1037 #endif
1038 }
1039
1040 /*
1041 * Ftrace disable/restore without lock. Some synchronization mechanism
1042 * must be used to prevent ftrace_enabled to be changed between
1043 * disable/restore.
1044 */
__ftrace_enabled_save(void)1045 static inline int __ftrace_enabled_save(void)
1046 {
1047 #ifdef CONFIG_FUNCTION_TRACER
1048 int saved_ftrace_enabled = ftrace_enabled;
1049 ftrace_enabled = 0;
1050 return saved_ftrace_enabled;
1051 #else
1052 return 0;
1053 #endif
1054 }
1055
__ftrace_enabled_restore(int enabled)1056 static inline void __ftrace_enabled_restore(int enabled)
1057 {
1058 #ifdef CONFIG_FUNCTION_TRACER
1059 ftrace_enabled = enabled;
1060 #endif
1061 }
1062
1063 /* All archs should have this, but we define it for consistency */
1064 #ifndef ftrace_return_address0
1065 # define ftrace_return_address0 __builtin_return_address(0)
1066 #endif
1067
1068 /* Archs may use other ways for ADDR1 and beyond */
1069 #ifndef ftrace_return_address
1070 # ifdef CONFIG_FRAME_POINTER
1071 # define ftrace_return_address(n) __builtin_return_address(n)
1072 # else
1073 # define ftrace_return_address(n) 0UL
1074 # endif
1075 #endif
1076
1077 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
1078 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
1079 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
1080 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
1081 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
1082 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
1083 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
1084
get_lock_parent_ip(void)1085 static __always_inline unsigned long get_lock_parent_ip(void)
1086 {
1087 unsigned long addr = CALLER_ADDR0;
1088
1089 if (!in_lock_functions(addr))
1090 return addr;
1091 addr = CALLER_ADDR1;
1092 if (!in_lock_functions(addr))
1093 return addr;
1094 return CALLER_ADDR2;
1095 }
1096
1097 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
1098 extern void trace_preempt_on(unsigned long a0, unsigned long a1);
1099 extern void trace_preempt_off(unsigned long a0, unsigned long a1);
1100 #else
1101 /*
1102 * Use defines instead of static inlines because some arches will make code out
1103 * of the CALLER_ADDR, when we really want these to be a real nop.
1104 */
1105 # define trace_preempt_on(a0, a1) do { } while (0)
1106 # define trace_preempt_off(a0, a1) do { } while (0)
1107 #endif
1108
1109 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
1110 extern void ftrace_init(void);
1111 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
1112 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries"
1113 #else
1114 #define FTRACE_CALLSITE_SECTION "__mcount_loc"
1115 #endif
1116 #else
ftrace_init(void)1117 static inline void ftrace_init(void) { }
1118 #endif
1119
1120 /*
1121 * Structure that defines an entry function trace.
1122 * It's already packed but the attribute "packed" is needed
1123 * to remove extra padding at the end.
1124 */
1125 struct ftrace_graph_ent {
1126 unsigned long func; /* Current function */
1127 int depth;
1128 } __packed;
1129
1130 /*
1131 * Structure that defines an entry function trace with retaddr.
1132 * It's already packed but the attribute "packed" is needed
1133 * to remove extra padding at the end.
1134 */
1135 struct fgraph_retaddr_ent {
1136 unsigned long func; /* Current function */
1137 int depth;
1138 unsigned long retaddr; /* Return address */
1139 } __packed;
1140
1141 /*
1142 * Structure that defines a return function trace.
1143 * It's already packed but the attribute "packed" is needed
1144 * to remove extra padding at the end.
1145 */
1146 struct ftrace_graph_ret {
1147 unsigned long func; /* Current function */
1148 #ifdef CONFIG_FUNCTION_GRAPH_RETVAL
1149 unsigned long retval;
1150 #endif
1151 int depth;
1152 /* Number of functions that overran the depth limit for current task */
1153 unsigned int overrun;
1154 } __packed;
1155
1156 struct fgraph_ops;
1157
1158 /* Type of the callback handlers for tracing function graph*/
1159 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *,
1160 struct fgraph_ops *,
1161 struct ftrace_regs *); /* return */
1162 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *,
1163 struct fgraph_ops *,
1164 struct ftrace_regs *); /* entry */
1165
1166 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace,
1167 struct fgraph_ops *gops,
1168 struct ftrace_regs *fregs);
1169 bool ftrace_pids_enabled(struct ftrace_ops *ops);
1170
1171 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1172
1173 struct fgraph_ops {
1174 trace_func_graph_ent_t entryfunc;
1175 trace_func_graph_ret_t retfunc;
1176 struct ftrace_ops ops; /* for the hash lists */
1177 void *private;
1178 trace_func_graph_ent_t saved_func;
1179 int idx;
1180 };
1181
1182 void *fgraph_reserve_data(int idx, int size_bytes);
1183 void *fgraph_retrieve_data(int idx, int *size_bytes);
1184 void *fgraph_retrieve_parent_data(int idx, int *size_bytes, int depth);
1185
1186 /*
1187 * Stack of return addresses for functions
1188 * of a thread.
1189 * Used in struct thread_info
1190 */
1191 struct ftrace_ret_stack {
1192 unsigned long ret;
1193 unsigned long func;
1194 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
1195 unsigned long fp;
1196 #endif
1197 unsigned long *retp;
1198 };
1199
1200 /*
1201 * Primary handler of a function return.
1202 * It relays on ftrace_return_to_handler.
1203 * Defined in entry_32/64.S
1204 */
1205 extern void return_to_handler(void);
1206
1207 extern int
1208 function_graph_enter_regs(unsigned long ret, unsigned long func,
1209 unsigned long frame_pointer, unsigned long *retp,
1210 struct ftrace_regs *fregs);
1211
function_graph_enter(unsigned long ret,unsigned long func,unsigned long fp,unsigned long * retp)1212 static inline int function_graph_enter(unsigned long ret, unsigned long func,
1213 unsigned long fp, unsigned long *retp)
1214 {
1215 return function_graph_enter_regs(ret, func, fp, retp, NULL);
1216 }
1217
1218 struct ftrace_ret_stack *
1219 ftrace_graph_get_ret_stack(struct task_struct *task, int skip);
1220 unsigned long ftrace_graph_top_ret_addr(struct task_struct *task);
1221
1222 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
1223 unsigned long ret, unsigned long *retp);
1224 unsigned long *fgraph_get_task_var(struct fgraph_ops *gops);
1225
1226 /*
1227 * Sometimes we don't want to trace a function with the function
1228 * graph tracer but we want them to keep traced by the usual function
1229 * tracer if the function graph tracer is not configured.
1230 */
1231 #define __notrace_funcgraph notrace
1232
1233 #define FTRACE_RETFUNC_DEPTH 50
1234 #define FTRACE_RETSTACK_ALLOC_SIZE 32
1235
1236 extern int register_ftrace_graph(struct fgraph_ops *ops);
1237 extern void unregister_ftrace_graph(struct fgraph_ops *ops);
1238
1239 /**
1240 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
1241 *
1242 * ftrace_graph_stop() is called when a severe error is detected in
1243 * the function graph tracing. This function is called by the critical
1244 * paths of function graph to keep those paths from doing any more harm.
1245 */
1246 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph);
1247
ftrace_graph_is_dead(void)1248 static inline bool ftrace_graph_is_dead(void)
1249 {
1250 return static_branch_unlikely(&kill_ftrace_graph);
1251 }
1252
1253 extern void ftrace_graph_stop(void);
1254
1255 /* The current handlers in use */
1256 extern trace_func_graph_ret_t ftrace_graph_return;
1257 extern trace_func_graph_ent_t ftrace_graph_entry;
1258
1259 extern void ftrace_graph_init_task(struct task_struct *t);
1260 extern void ftrace_graph_exit_task(struct task_struct *t);
1261 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
1262
1263 /* Used by assembly, but to quiet sparse warnings */
1264 extern struct ftrace_ops *function_trace_op;
1265
pause_graph_tracing(void)1266 static inline void pause_graph_tracing(void)
1267 {
1268 atomic_inc(¤t->tracing_graph_pause);
1269 }
1270
unpause_graph_tracing(void)1271 static inline void unpause_graph_tracing(void)
1272 {
1273 atomic_dec(¤t->tracing_graph_pause);
1274 }
1275 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
1276
1277 #define __notrace_funcgraph
1278
ftrace_graph_init_task(struct task_struct * t)1279 static inline void ftrace_graph_init_task(struct task_struct *t) { }
ftrace_graph_exit_task(struct task_struct * t)1280 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
ftrace_graph_init_idle_task(struct task_struct * t,int cpu)1281 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
1282
1283 /* Define as macros as fgraph_ops may not be defined */
1284 #define register_ftrace_graph(ops) ({ -1; })
1285 #define unregister_ftrace_graph(ops) do { } while (0)
1286
1287 static inline unsigned long
ftrace_graph_ret_addr(struct task_struct * task,int * idx,unsigned long ret,unsigned long * retp)1288 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
1289 unsigned long *retp)
1290 {
1291 return ret;
1292 }
1293
pause_graph_tracing(void)1294 static inline void pause_graph_tracing(void) { }
unpause_graph_tracing(void)1295 static inline void unpause_graph_tracing(void) { }
1296 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1297
1298 #ifdef CONFIG_TRACING
1299 enum ftrace_dump_mode;
1300
1301 #define MAX_TRACER_SIZE 100
1302 extern char ftrace_dump_on_oops[];
1303 extern int ftrace_dump_on_oops_enabled(void);
1304 extern int tracepoint_printk;
1305
1306 extern void disable_trace_on_warning(void);
1307 extern int __disable_trace_on_warning;
1308
1309 int tracepoint_printk_sysctl(const struct ctl_table *table, int write,
1310 void *buffer, size_t *lenp, loff_t *ppos);
1311
1312 #else /* CONFIG_TRACING */
disable_trace_on_warning(void)1313 static inline void disable_trace_on_warning(void) { }
1314 #endif /* CONFIG_TRACING */
1315
1316 #ifdef CONFIG_FTRACE_SYSCALLS
1317
1318 unsigned long arch_syscall_addr(int nr);
1319
1320 #endif /* CONFIG_FTRACE_SYSCALLS */
1321
1322 #endif /* _LINUX_FTRACE_H */
1323