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 #ifndef arch_ftrace_partial_regs
197 #define arch_ftrace_partial_regs(regs) do {} while (0)
198 #endif
199
200 static __always_inline struct pt_regs *
ftrace_partial_regs(struct ftrace_regs * fregs,struct pt_regs * regs)201 ftrace_partial_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
202 {
203 /*
204 * If CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS=y, ftrace_regs memory
205 * layout is including pt_regs. So always returns that address.
206 * Since arch_ftrace_get_regs() will check some members and may return
207 * NULL, we can not use it.
208 */
209 regs = &arch_ftrace_regs(fregs)->regs;
210
211 /* Allow arch specific updates to regs. */
212 arch_ftrace_partial_regs(regs);
213 return regs;
214 }
215
216 #endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS || CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */
217
218 #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
219
220 /*
221 * Please define arch dependent pt_regs which compatible to the
222 * perf_arch_fetch_caller_regs() but based on ftrace_regs.
223 * This requires
224 * - user_mode(_regs) returns false (always kernel mode).
225 * - able to use the _regs for stack trace.
226 */
227 #ifndef arch_ftrace_fill_perf_regs
228 /* As same as perf_arch_fetch_caller_regs(), do nothing by default */
229 #define arch_ftrace_fill_perf_regs(fregs, _regs) do {} while (0)
230 #endif
231
232 static __always_inline struct pt_regs *
ftrace_fill_perf_regs(struct ftrace_regs * fregs,struct pt_regs * regs)233 ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
234 {
235 arch_ftrace_fill_perf_regs(fregs, regs);
236 return regs;
237 }
238
239 #else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
240
241 static __always_inline struct pt_regs *
ftrace_fill_perf_regs(struct ftrace_regs * fregs,struct pt_regs * regs)242 ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)
243 {
244 return &arch_ftrace_regs(fregs)->regs;
245 }
246
247 #endif
248
249 /*
250 * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs.
251 * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs.
252 */
ftrace_regs_has_args(struct ftrace_regs * fregs)253 static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
254 {
255 if (IS_ENABLED(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS))
256 return true;
257
258 return ftrace_get_regs(fregs) != NULL;
259 }
260
261 #ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
262 static __always_inline unsigned long
ftrace_regs_get_kernel_stack_nth(struct ftrace_regs * fregs,unsigned int nth)263 ftrace_regs_get_kernel_stack_nth(struct ftrace_regs *fregs, unsigned int nth)
264 {
265 unsigned long *stackp;
266
267 stackp = (unsigned long *)ftrace_regs_get_stack_pointer(fregs);
268 if (((unsigned long)(stackp + nth) & ~(THREAD_SIZE - 1)) ==
269 ((unsigned long)stackp & ~(THREAD_SIZE - 1)))
270 return *(stackp + nth);
271
272 return 0;
273 }
274 #else /* !CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */
275 #define ftrace_regs_get_kernel_stack_nth(fregs, nth) (0L)
276 #endif /* CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */
277
278 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
279 struct ftrace_ops *op, struct ftrace_regs *fregs);
280
281 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
282
283 /*
284 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
285 * set in the flags member.
286 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
287 * IPMODIFY are a kind of attribute flags which can be set only before
288 * registering the ftrace_ops, and can not be modified while registered.
289 * Changing those attribute flags after registering ftrace_ops will
290 * cause unexpected results.
291 *
292 * ENABLED - set/unset when ftrace_ops is registered/unregistered
293 * DYNAMIC - set when ftrace_ops is registered to denote dynamically
294 * allocated ftrace_ops which need special care
295 * SAVE_REGS - The ftrace_ops wants regs saved at each function called
296 * and passed to the callback. If this flag is set, but the
297 * architecture does not support passing regs
298 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
299 * ftrace_ops will fail to register, unless the next flag
300 * is set.
301 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
302 * handler can handle an arch that does not save regs
303 * (the handler tests if regs == NULL), then it can set
304 * this flag instead. It will not fail registering the ftrace_ops
305 * but, the regs field will be NULL if the arch does not support
306 * passing regs to the handler.
307 * Note, if this flag is set, the SAVE_REGS flag will automatically
308 * get set upon registering the ftrace_ops, if the arch supports it.
309 * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
310 * that the call back needs recursion protection. If it does
311 * not set this, then the ftrace infrastructure will assume
312 * that the callback can handle recursion on its own.
313 * STUB - The ftrace_ops is just a place holder.
314 * INITIALIZED - The ftrace_ops has already been initialized (first use time
315 * register_ftrace_function() is called, it will initialized the ops)
316 * DELETED - The ops are being deleted, do not let them be registered again.
317 * ADDING - The ops is in the process of being added.
318 * REMOVING - The ops is in the process of being removed.
319 * MODIFYING - The ops is in the process of changing its filter functions.
320 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
321 * The arch specific code sets this flag when it allocated a
322 * trampoline. This lets the arch know that it can update the
323 * trampoline in case the callback function changes.
324 * The ftrace_ops trampoline can be set by the ftrace users, and
325 * in such cases the arch must not modify it. Only the arch ftrace
326 * core code should set this flag.
327 * IPMODIFY - The ops can modify the IP register. This can only be set with
328 * SAVE_REGS. If another ops with this flag set is already registered
329 * for any of the functions that this ops will be registered for, then
330 * this ops will fail to register or set_filter_ip.
331 * PID - Is affected by set_ftrace_pid (allows filtering on those pids)
332 * RCU - Set when the ops can only be called when RCU is watching.
333 * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
334 * PERMANENT - Set when the ops is permanent and should not be affected by
335 * ftrace_enabled.
336 * DIRECT - Used by the direct ftrace_ops helper for direct functions
337 * (internal ftrace only, should not be used by others)
338 * SUBOP - Is controlled by another op in field managed.
339 * GRAPH - Is a component of the fgraph_ops structure
340 */
341 enum {
342 FTRACE_OPS_FL_ENABLED = BIT(0),
343 FTRACE_OPS_FL_DYNAMIC = BIT(1),
344 FTRACE_OPS_FL_SAVE_REGS = BIT(2),
345 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3),
346 FTRACE_OPS_FL_RECURSION = BIT(4),
347 FTRACE_OPS_FL_STUB = BIT(5),
348 FTRACE_OPS_FL_INITIALIZED = BIT(6),
349 FTRACE_OPS_FL_DELETED = BIT(7),
350 FTRACE_OPS_FL_ADDING = BIT(8),
351 FTRACE_OPS_FL_REMOVING = BIT(9),
352 FTRACE_OPS_FL_MODIFYING = BIT(10),
353 FTRACE_OPS_FL_ALLOC_TRAMP = BIT(11),
354 FTRACE_OPS_FL_IPMODIFY = BIT(12),
355 FTRACE_OPS_FL_PID = BIT(13),
356 FTRACE_OPS_FL_RCU = BIT(14),
357 FTRACE_OPS_FL_TRACE_ARRAY = BIT(15),
358 FTRACE_OPS_FL_PERMANENT = BIT(16),
359 FTRACE_OPS_FL_DIRECT = BIT(17),
360 FTRACE_OPS_FL_SUBOP = BIT(18),
361 FTRACE_OPS_FL_GRAPH = BIT(19),
362 FTRACE_OPS_FL_JMP = BIT(20),
363 };
364
365 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
366 #define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS
367 #else
368 #define FTRACE_OPS_FL_SAVE_ARGS 0
369 #endif
370
371 /*
372 * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes
373 * to a ftrace_ops. Note, the requests may fail.
374 *
375 * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same
376 * function as an ops with IPMODIFY. Called
377 * when the DIRECT ops is being registered.
378 * This is called with both direct_mutex and
379 * ftrace_lock are locked.
380 *
381 * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same
382 * function as an ops with IPMODIFY. Called
383 * when the other ops (the one with IPMODIFY)
384 * is being registered.
385 * This is called with direct_mutex locked.
386 *
387 * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same
388 * function as an ops with IPMODIFY. Called
389 * when the other ops (the one with IPMODIFY)
390 * is being unregistered.
391 * This is called with direct_mutex locked.
392 */
393 enum ftrace_ops_cmd {
394 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF,
395 FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER,
396 FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER,
397 };
398
399 /*
400 * For most ftrace_ops_cmd,
401 * Returns:
402 * 0 - Success.
403 * Negative on failure. The return value is dependent on the
404 * callback.
405 */
406 typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd);
407
408 #ifdef CONFIG_DYNAMIC_FTRACE
409 /* The hash used to know what functions callbacks trace */
410 struct ftrace_ops_hash {
411 struct ftrace_hash __rcu *notrace_hash;
412 struct ftrace_hash __rcu *filter_hash;
413 struct mutex regex_lock;
414 };
415
416 void ftrace_free_init_mem(void);
417 void ftrace_free_mem(struct module *mod, void *start, void *end);
418 #else
ftrace_free_init_mem(void)419 static inline void ftrace_free_init_mem(void)
420 {
421 ftrace_boot_snapshot();
422 }
ftrace_free_mem(struct module * mod,void * start,void * end)423 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
424 #endif
425
426 /*
427 * Note, ftrace_ops can be referenced outside of RCU protection, unless
428 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
429 * core data, the unregistering of it will perform a scheduling on all CPUs
430 * to make sure that there are no more users. Depending on the load of the
431 * system that may take a bit of time.
432 *
433 * Any private data added must also take care not to be freed and if private
434 * data is added to a ftrace_ops that is in core code, the user of the
435 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
436 */
437 struct ftrace_ops {
438 ftrace_func_t func;
439 struct ftrace_ops __rcu *next;
440 unsigned long flags;
441 void *private;
442 ftrace_func_t saved_func;
443 #ifdef CONFIG_DYNAMIC_FTRACE
444 struct ftrace_ops_hash local_hash;
445 struct ftrace_ops_hash *func_hash;
446 struct ftrace_ops_hash old_hash;
447 unsigned long trampoline;
448 unsigned long trampoline_size;
449 struct list_head list;
450 struct list_head subop_list;
451 ftrace_ops_func_t ops_func;
452 struct ftrace_ops *managed;
453 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
454 unsigned long direct_call;
455 #endif
456 #endif
457 };
458
459 extern struct ftrace_ops __rcu *ftrace_ops_list;
460 extern struct ftrace_ops ftrace_list_end;
461
462 /*
463 * Traverse the ftrace_ops_list, invoking all entries. The reason that we
464 * can use rcu_dereference_raw_check() is that elements removed from this list
465 * are simply leaked, so there is no need to interact with a grace-period
466 * mechanism. The rcu_dereference_raw_check() calls are needed to handle
467 * concurrent insertions into the ftrace_ops_list.
468 *
469 * Silly Alpha and silly pointer-speculation compiler optimizations!
470 */
471 #define do_for_each_ftrace_op(op, list) \
472 op = rcu_dereference_raw_check(list); \
473 do
474
475 /*
476 * Optimized for just a single item in the list (as that is the normal case).
477 */
478 #define while_for_each_ftrace_op(op) \
479 while (likely(op = rcu_dereference_raw_check((op)->next)) && \
480 unlikely((op) != &ftrace_list_end))
481
482 /*
483 * Type of the current tracing.
484 */
485 enum ftrace_tracing_type_t {
486 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
487 FTRACE_TYPE_RETURN, /* Hook the return of the function */
488 };
489
490 /* Current tracing type, default is FTRACE_TYPE_ENTER */
491 extern enum ftrace_tracing_type_t ftrace_tracing_type;
492
493 /*
494 * The ftrace_ops must be a static and should also
495 * be read_mostly. These functions do modify read_mostly variables
496 * so use them sparely. Never free an ftrace_op or modify the
497 * next pointer after it has been registered. Even after unregistering
498 * it, the next pointer may still be used internally.
499 */
500 int register_ftrace_function(struct ftrace_ops *ops);
501 int unregister_ftrace_function(struct ftrace_ops *ops);
502
503 extern void ftrace_stub(unsigned long a0, unsigned long a1,
504 struct ftrace_ops *op, struct ftrace_regs *fregs);
505
506
507 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs);
508 #else /* !CONFIG_FUNCTION_TRACER */
509 /*
510 * (un)register_ftrace_function must be a macro since the ops parameter
511 * must not be evaluated.
512 */
513 #define register_ftrace_function(ops) ({ 0; })
514 #define unregister_ftrace_function(ops) ({ 0; })
ftrace_kill(void)515 static inline void ftrace_kill(void) { }
ftrace_free_init_mem(void)516 static inline void ftrace_free_init_mem(void) { }
ftrace_free_mem(struct module * mod,void * start,void * end)517 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)518 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
519 {
520 return -EOPNOTSUPP;
521 }
522 #endif /* CONFIG_FUNCTION_TRACER */
523
524 struct ftrace_func_entry {
525 struct hlist_node hlist;
526 unsigned long ip;
527 unsigned long direct; /* for direct lookup only */
528 };
529
530 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
531 unsigned long ftrace_find_rec_direct(unsigned long ip);
532 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
533 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
534 bool free_filters);
535 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
536 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr);
537
538 void ftrace_stub_direct_tramp(void);
539
540 #else
541 struct ftrace_ops;
ftrace_find_rec_direct(unsigned long ip)542 static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
543 {
544 return 0;
545 }
register_ftrace_direct(struct ftrace_ops * ops,unsigned long addr)546 static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
547 {
548 return -ENODEV;
549 }
unregister_ftrace_direct(struct ftrace_ops * ops,unsigned long addr,bool free_filters)550 static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
551 bool free_filters)
552 {
553 return -ENODEV;
554 }
modify_ftrace_direct(struct ftrace_ops * ops,unsigned long addr)555 static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
556 {
557 return -ENODEV;
558 }
modify_ftrace_direct_nolock(struct ftrace_ops * ops,unsigned long addr)559 static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
560 {
561 return -ENODEV;
562 }
563
564 /*
565 * This must be implemented by the architecture.
566 * It is the way the ftrace direct_ops helper, when called
567 * via ftrace (because there's other callbacks besides the
568 * direct call), can inform the architecture's trampoline that this
569 * routine has a direct caller, and what the caller is.
570 *
571 * For example, in x86, it returns the direct caller
572 * callback function via the regs->orig_ax parameter.
573 * Then in the ftrace trampoline, if this is set, it makes
574 * the return from the trampoline jump to the direct caller
575 * instead of going back to the function it just traced.
576 */
arch_ftrace_set_direct_caller(struct ftrace_regs * fregs,unsigned long addr)577 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
578 unsigned long addr) { }
579 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
580
581 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_JMP
ftrace_is_jmp(unsigned long addr)582 static inline bool ftrace_is_jmp(unsigned long addr)
583 {
584 return addr & 1;
585 }
586
ftrace_jmp_set(unsigned long addr)587 static inline unsigned long ftrace_jmp_set(unsigned long addr)
588 {
589 return addr | 1UL;
590 }
591
ftrace_jmp_get(unsigned long addr)592 static inline unsigned long ftrace_jmp_get(unsigned long addr)
593 {
594 return addr & ~1UL;
595 }
596 #else
ftrace_is_jmp(unsigned long addr)597 static inline bool ftrace_is_jmp(unsigned long addr)
598 {
599 return false;
600 }
601
ftrace_jmp_set(unsigned long addr)602 static inline unsigned long ftrace_jmp_set(unsigned long addr)
603 {
604 return addr;
605 }
606
ftrace_jmp_get(unsigned long addr)607 static inline unsigned long ftrace_jmp_get(unsigned long addr)
608 {
609 return addr;
610 }
611 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_JMP */
612
613 #ifdef CONFIG_STACK_TRACER
614
615 int stack_trace_sysctl(const struct ctl_table *table, int write, void *buffer,
616 size_t *lenp, loff_t *ppos);
617
618 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
619 DECLARE_PER_CPU(int, disable_stack_tracer);
620
621 /**
622 * stack_tracer_disable - temporarily disable the stack tracer
623 *
624 * There's a few locations (namely in RCU) where stack tracing
625 * cannot be executed. This function is used to disable stack
626 * tracing during those critical sections.
627 *
628 * This function must be called with preemption or interrupts
629 * disabled and stack_tracer_enable() must be called shortly after
630 * while preemption or interrupts are still disabled.
631 */
stack_tracer_disable(void)632 static inline void stack_tracer_disable(void)
633 {
634 /* Preemption or interrupts must be disabled */
635 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
636 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
637 this_cpu_inc(disable_stack_tracer);
638 }
639
640 /**
641 * stack_tracer_enable - re-enable the stack tracer
642 *
643 * After stack_tracer_disable() is called, stack_tracer_enable()
644 * must be called shortly afterward.
645 */
stack_tracer_enable(void)646 static inline void stack_tracer_enable(void)
647 {
648 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
649 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
650 this_cpu_dec(disable_stack_tracer);
651 }
652 #else
stack_tracer_disable(void)653 static inline void stack_tracer_disable(void) { }
stack_tracer_enable(void)654 static inline void stack_tracer_enable(void) { }
655 #endif
656
657 enum {
658 FTRACE_UPDATE_CALLS = (1 << 0),
659 FTRACE_DISABLE_CALLS = (1 << 1),
660 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
661 FTRACE_START_FUNC_RET = (1 << 3),
662 FTRACE_STOP_FUNC_RET = (1 << 4),
663 FTRACE_MAY_SLEEP = (1 << 5),
664 };
665
666 /* Arches can override ftrace_get_symaddr() to convert fentry_ip to symaddr. */
667 #ifndef ftrace_get_symaddr
668 /**
669 * ftrace_get_symaddr - return the symbol address from fentry_ip
670 * @fentry_ip: the address of ftrace location
671 *
672 * Get the symbol address from @fentry_ip (fast path). If there is no fast
673 * search path, this returns 0.
674 * User may need to use kallsyms API to find the symbol address.
675 */
676 #define ftrace_get_symaddr(fentry_ip) (0)
677 #endif
678
679 void ftrace_sync_ipi(void *data);
680
681 #ifdef CONFIG_DYNAMIC_FTRACE
682
683 void ftrace_arch_code_modify_prepare(void);
684 void ftrace_arch_code_modify_post_process(void);
685
686 enum ftrace_bug_type {
687 FTRACE_BUG_UNKNOWN,
688 FTRACE_BUG_INIT,
689 FTRACE_BUG_NOP,
690 FTRACE_BUG_CALL,
691 FTRACE_BUG_UPDATE,
692 };
693 extern enum ftrace_bug_type ftrace_bug_type;
694
695 /*
696 * Archs can set this to point to a variable that holds the value that was
697 * expected at the call site before calling ftrace_bug().
698 */
699 extern const void *ftrace_expected;
700
701 void ftrace_bug(int err, struct dyn_ftrace *rec);
702
703 struct seq_file;
704
705 extern int ftrace_text_reserved(const void *start, const void *end);
706
707 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
708
709 bool is_ftrace_trampoline(unsigned long addr);
710
711 /*
712 * The dyn_ftrace record's flags field is split into two parts.
713 * the first part which is '0-FTRACE_REF_MAX' is a counter of
714 * the number of callbacks that have registered the function that
715 * the dyn_ftrace descriptor represents.
716 *
717 * The second part is a mask:
718 * ENABLED - the function is being traced
719 * REGS - the record wants the function to save regs
720 * REGS_EN - the function is set up to save regs.
721 * IPMODIFY - the record allows for the IP address to be changed.
722 * DISABLED - the record is not ready to be touched yet
723 * DIRECT - there is a direct function to call
724 * CALL_OPS - the record can use callsite-specific ops
725 * CALL_OPS_EN - the function is set up to use callsite-specific ops
726 * TOUCHED - A callback was added since boot up
727 * MODIFIED - The function had IPMODIFY or DIRECT attached to it
728 *
729 * When a new ftrace_ops is registered and wants a function to save
730 * pt_regs, the rec->flags REGS is set. When the function has been
731 * set up to save regs, the REG_EN flag is set. Once a function
732 * starts saving regs it will do so until all ftrace_ops are removed
733 * from tracing that function.
734 */
735 enum {
736 FTRACE_FL_ENABLED = (1UL << 31),
737 FTRACE_FL_REGS = (1UL << 30),
738 FTRACE_FL_REGS_EN = (1UL << 29),
739 FTRACE_FL_TRAMP = (1UL << 28),
740 FTRACE_FL_TRAMP_EN = (1UL << 27),
741 FTRACE_FL_IPMODIFY = (1UL << 26),
742 FTRACE_FL_DISABLED = (1UL << 25),
743 FTRACE_FL_DIRECT = (1UL << 24),
744 FTRACE_FL_DIRECT_EN = (1UL << 23),
745 FTRACE_FL_CALL_OPS = (1UL << 22),
746 FTRACE_FL_CALL_OPS_EN = (1UL << 21),
747 FTRACE_FL_TOUCHED = (1UL << 20),
748 FTRACE_FL_MODIFIED = (1UL << 19),
749 };
750
751 #define FTRACE_REF_MAX_SHIFT 19
752 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
753
754 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX)
755
756 struct dyn_ftrace {
757 unsigned long ip; /* address of mcount call-site */
758 unsigned long flags;
759 struct dyn_arch_ftrace arch;
760 };
761
762 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
763 int remove, int reset);
764 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
765 unsigned int cnt, int remove, int reset);
766 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
767 int len, int reset);
768 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
769 int len, int reset);
770 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
771 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
772 void ftrace_free_filter(struct ftrace_ops *ops);
773 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
774
775 /*
776 * The FTRACE_UPDATE_* enum is used to pass information back
777 * from the ftrace_update_record() and ftrace_test_record()
778 * functions. These are called by the code update routines
779 * to find out what is to be done for a given function.
780 *
781 * IGNORE - The function is already what we want it to be
782 * MAKE_CALL - Start tracing the function
783 * MODIFY_CALL - Stop saving regs for the function
784 * MAKE_NOP - Stop tracing the function
785 */
786 enum {
787 FTRACE_UPDATE_IGNORE,
788 FTRACE_UPDATE_MAKE_CALL,
789 FTRACE_UPDATE_MODIFY_CALL,
790 FTRACE_UPDATE_MAKE_NOP,
791 };
792
793 enum {
794 FTRACE_ITER_FILTER = (1 << 0),
795 FTRACE_ITER_NOTRACE = (1 << 1),
796 FTRACE_ITER_PRINTALL = (1 << 2),
797 FTRACE_ITER_DO_PROBES = (1 << 3),
798 FTRACE_ITER_PROBE = (1 << 4),
799 FTRACE_ITER_MOD = (1 << 5),
800 FTRACE_ITER_ENABLED = (1 << 6),
801 FTRACE_ITER_TOUCHED = (1 << 7),
802 FTRACE_ITER_ADDRS = (1 << 8),
803 };
804
805 void arch_ftrace_update_code(int command);
806 void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
807 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
808 void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
809
810 struct ftrace_rec_iter;
811
812 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
813 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
814 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
815
816 #define for_ftrace_rec_iter(iter) \
817 for (iter = ftrace_rec_iter_start(); \
818 iter; \
819 iter = ftrace_rec_iter_next(iter))
820
821
822 int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
823 int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
824 void ftrace_run_stop_machine(int command);
825 unsigned long ftrace_location(unsigned long ip);
826 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
827 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
828 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
829
830 extern ftrace_func_t ftrace_trace_function;
831
832 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
833 struct inode *inode, struct file *file);
834 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
835 size_t cnt, loff_t *ppos);
836 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
837 size_t cnt, loff_t *ppos);
838 int ftrace_regex_release(struct inode *inode, struct file *file);
839
840 void __init
841 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
842
843 /* defined in arch */
844 extern int ftrace_dyn_arch_init(void);
845 extern void ftrace_replace_code(int enable);
846 extern int ftrace_update_ftrace_func(ftrace_func_t func);
847 extern void ftrace_caller(void);
848 extern void ftrace_regs_caller(void);
849 extern void ftrace_call(void);
850 extern void ftrace_regs_call(void);
851 extern void mcount_call(void);
852
853 void ftrace_modify_all_code(int command);
854
855 #ifndef FTRACE_ADDR
856 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
857 #endif
858
859 #ifndef FTRACE_GRAPH_ADDR
860 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
861 #endif
862
863 #ifndef FTRACE_REGS_ADDR
864 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
865 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
866 #else
867 # define FTRACE_REGS_ADDR FTRACE_ADDR
868 #endif
869 #endif
870
871 /*
872 * If an arch would like functions that are only traced
873 * by the function graph tracer to jump directly to its own
874 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
875 * to be that address to jump to.
876 */
877 #ifndef FTRACE_GRAPH_TRAMP_ADDR
878 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
879 #endif
880
881 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
882 extern void ftrace_graph_caller(void);
883 extern int ftrace_enable_ftrace_graph_caller(void);
884 extern int ftrace_disable_ftrace_graph_caller(void);
885 #else
ftrace_enable_ftrace_graph_caller(void)886 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
ftrace_disable_ftrace_graph_caller(void)887 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
888 #endif
889
890 /**
891 * ftrace_make_nop - convert code into nop
892 * @mod: module structure if called by module load initialization
893 * @rec: the call site record (e.g. mcount/fentry)
894 * @addr: the address that the call site should be calling
895 *
896 * This is a very sensitive operation and great care needs
897 * to be taken by the arch. The operation should carefully
898 * read the location, check to see if what is read is indeed
899 * what we expect it to be, and then on success of the compare,
900 * it should write to the location.
901 *
902 * The code segment at @rec->ip should be a caller to @addr
903 *
904 * Return must be:
905 * 0 on success
906 * -EFAULT on error reading the location
907 * -EINVAL on a failed compare of the contents
908 * -EPERM on error writing to the location
909 * Any other value will be considered a failure.
910 */
911 extern int ftrace_make_nop(struct module *mod,
912 struct dyn_ftrace *rec, unsigned long addr);
913
914 /**
915 * ftrace_need_init_nop - return whether nop call sites should be initialized
916 *
917 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't
918 * need to call ftrace_init_nop() if the code is built with that flag.
919 * Architectures where this is not always the case may define their own
920 * condition.
921 *
922 * Return must be:
923 * 0 if ftrace_init_nop() should be called
924 * Nonzero if ftrace_init_nop() should not be called
925 */
926
927 #ifndef ftrace_need_init_nop
928 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT))
929 #endif
930
931 /**
932 * ftrace_init_nop - initialize a nop call site
933 * @mod: module structure if called by module load initialization
934 * @rec: the call site record (e.g. mcount/fentry)
935 *
936 * This is a very sensitive operation and great care needs
937 * to be taken by the arch. The operation should carefully
938 * read the location, check to see if what is read is indeed
939 * what we expect it to be, and then on success of the compare,
940 * it should write to the location.
941 *
942 * The code segment at @rec->ip should contain the contents created by
943 * the compiler
944 *
945 * Return must be:
946 * 0 on success
947 * -EFAULT on error reading the location
948 * -EINVAL on a failed compare of the contents
949 * -EPERM on error writing to the location
950 * Any other value will be considered a failure.
951 */
952 #ifndef ftrace_init_nop
ftrace_init_nop(struct module * mod,struct dyn_ftrace * rec)953 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
954 {
955 return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
956 }
957 #endif
958
959 /**
960 * ftrace_make_call - convert a nop call site into a call to addr
961 * @rec: the call site record (e.g. mcount/fentry)
962 * @addr: the address that the call site should call
963 *
964 * This is a very sensitive operation and great care needs
965 * to be taken by the arch. The operation should carefully
966 * read the location, check to see if what is read is indeed
967 * what we expect it to be, and then on success of the compare,
968 * it should write to the location.
969 *
970 * The code segment at @rec->ip should be a nop
971 *
972 * Return must be:
973 * 0 on success
974 * -EFAULT on error reading the location
975 * -EINVAL on a failed compare of the contents
976 * -EPERM on error writing to the location
977 * Any other value will be considered a failure.
978 */
979 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
980
981 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \
982 defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) || \
983 defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS)
984 /**
985 * ftrace_modify_call - convert from one addr to another (no nop)
986 * @rec: the call site record (e.g. mcount/fentry)
987 * @old_addr: the address expected to be currently called to
988 * @addr: the address to change to
989 *
990 * This is a very sensitive operation and great care needs
991 * to be taken by the arch. The operation should carefully
992 * read the location, check to see if what is read is indeed
993 * what we expect it to be, and then on success of the compare,
994 * it should write to the location.
995 *
996 * When using call ops, this is called when the associated ops change, even
997 * when (addr == old_addr).
998 *
999 * The code segment at @rec->ip should be a caller to @old_addr
1000 *
1001 * Return must be:
1002 * 0 on success
1003 * -EFAULT on error reading the location
1004 * -EINVAL on a failed compare of the contents
1005 * -EPERM on error writing to the location
1006 * Any other value will be considered a failure.
1007 */
1008 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
1009 unsigned long addr);
1010 #else
1011 /* Should never be called */
ftrace_modify_call(struct dyn_ftrace * rec,unsigned long old_addr,unsigned long addr)1012 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
1013 unsigned long addr)
1014 {
1015 return -EINVAL;
1016 }
1017 #endif
1018
1019 extern int skip_trace(unsigned long ip);
1020 extern void ftrace_module_init(struct module *mod);
1021 extern void ftrace_module_enable(struct module *mod);
1022 extern void ftrace_release_mod(struct module *mod);
1023 #else /* CONFIG_DYNAMIC_FTRACE */
skip_trace(unsigned long ip)1024 static inline int skip_trace(unsigned long ip) { return 0; }
ftrace_module_init(struct module * mod)1025 static inline void ftrace_module_init(struct module *mod) { }
ftrace_module_enable(struct module * mod)1026 static inline void ftrace_module_enable(struct module *mod) { }
ftrace_release_mod(struct module * mod)1027 static inline void ftrace_release_mod(struct module *mod) { }
ftrace_text_reserved(const void * start,const void * end)1028 static inline int ftrace_text_reserved(const void *start, const void *end)
1029 {
1030 return 0;
1031 }
ftrace_location(unsigned long ip)1032 static inline unsigned long ftrace_location(unsigned long ip)
1033 {
1034 return 0;
1035 }
1036
1037 /*
1038 * Again users of functions that have ftrace_ops may not
1039 * have them defined when ftrace is not enabled, but these
1040 * functions may still be called. Use a macro instead of inline.
1041 */
1042 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
1043 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
1044 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
1045 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; })
1046 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
1047 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
1048 #define ftrace_free_filter(ops) do { } while (0)
1049 #define ftrace_ops_set_global_filter(ops) do { } while (0)
1050
ftrace_filter_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)1051 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
1052 size_t cnt, loff_t *ppos) { return -ENODEV; }
ftrace_notrace_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)1053 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
1054 size_t cnt, loff_t *ppos) { return -ENODEV; }
1055 static inline int
ftrace_regex_release(struct inode * inode,struct file * file)1056 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
1057
is_ftrace_trampoline(unsigned long addr)1058 static inline bool is_ftrace_trampoline(unsigned long addr)
1059 {
1060 return false;
1061 }
1062 #endif /* CONFIG_DYNAMIC_FTRACE */
1063
1064 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1065 #ifndef ftrace_graph_func
1066 #define ftrace_graph_func ftrace_stub
1067 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB
1068 #else
1069 #define FTRACE_OPS_GRAPH_STUB 0
1070 #endif
1071 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1072
1073 /* totally disable ftrace - can not re-enable after this */
1074 void ftrace_kill(void);
1075
tracer_disable(void)1076 static inline void tracer_disable(void)
1077 {
1078 #ifdef CONFIG_FUNCTION_TRACER
1079 ftrace_enabled = 0;
1080 #endif
1081 }
1082
1083 /*
1084 * Ftrace disable/restore without lock. Some synchronization mechanism
1085 * must be used to prevent ftrace_enabled to be changed between
1086 * disable/restore.
1087 */
__ftrace_enabled_save(void)1088 static inline int __ftrace_enabled_save(void)
1089 {
1090 #ifdef CONFIG_FUNCTION_TRACER
1091 int saved_ftrace_enabled = ftrace_enabled;
1092 ftrace_enabled = 0;
1093 return saved_ftrace_enabled;
1094 #else
1095 return 0;
1096 #endif
1097 }
1098
__ftrace_enabled_restore(int enabled)1099 static inline void __ftrace_enabled_restore(int enabled)
1100 {
1101 #ifdef CONFIG_FUNCTION_TRACER
1102 ftrace_enabled = enabled;
1103 #endif
1104 }
1105
1106 /* All archs should have this, but we define it for consistency */
1107 #ifndef ftrace_return_address0
1108 # define ftrace_return_address0 __builtin_return_address(0)
1109 #endif
1110
1111 /* Archs may use other ways for ADDR1 and beyond */
1112 #ifndef ftrace_return_address
1113 # ifdef CONFIG_FRAME_POINTER
1114 # define ftrace_return_address(n) __builtin_return_address(n)
1115 # else
1116 # define ftrace_return_address(n) 0UL
1117 # endif
1118 #endif
1119
1120 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
1121 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
1122 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
1123 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
1124 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
1125 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
1126 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
1127
get_lock_parent_ip(void)1128 static __always_inline unsigned long get_lock_parent_ip(void)
1129 {
1130 unsigned long addr = CALLER_ADDR0;
1131
1132 if (!in_lock_functions(addr))
1133 return addr;
1134 addr = CALLER_ADDR1;
1135 if (!in_lock_functions(addr))
1136 return addr;
1137 return CALLER_ADDR2;
1138 }
1139
1140 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
1141 extern void trace_preempt_on(unsigned long a0, unsigned long a1);
1142 extern void trace_preempt_off(unsigned long a0, unsigned long a1);
1143 #else
1144 /*
1145 * Use defines instead of static inlines because some arches will make code out
1146 * of the CALLER_ADDR, when we really want these to be a real nop.
1147 */
1148 # define trace_preempt_on(a0, a1) do { } while (0)
1149 # define trace_preempt_off(a0, a1) do { } while (0)
1150 #endif
1151
1152 #ifdef CONFIG_DYNAMIC_FTRACE
1153 extern void ftrace_init(void);
1154 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
1155 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries"
1156 #else
1157 #define FTRACE_CALLSITE_SECTION "__mcount_loc"
1158 #endif
1159 #else
ftrace_init(void)1160 static inline void ftrace_init(void) { }
1161 #endif
1162
1163 /*
1164 * Structure that defines an entry function trace.
1165 * It's already packed but the attribute "packed" is needed
1166 * to remove extra padding at the end.
1167 */
1168 struct ftrace_graph_ent {
1169 unsigned long func; /* Current function */
1170 unsigned long depth;
1171 } __packed;
1172
1173 /*
1174 * Structure that defines an entry function trace with retaddr.
1175 */
1176 struct fgraph_retaddr_ent {
1177 struct ftrace_graph_ent ent;
1178 unsigned long retaddr; /* Return address */
1179 } __packed;
1180
1181 /*
1182 * Structure that defines a return function trace.
1183 * It's already packed but the attribute "packed" is needed
1184 * to remove extra padding at the end.
1185 */
1186 struct ftrace_graph_ret {
1187 unsigned long func; /* Current function */
1188 #ifdef CONFIG_FUNCTION_GRAPH_RETVAL
1189 unsigned long retval;
1190 #endif
1191 int depth;
1192 /* Number of functions that overran the depth limit for current task */
1193 unsigned int overrun;
1194 } __packed;
1195
1196 struct fgraph_ops;
1197
1198 /* Type of the callback handlers for tracing function graph*/
1199 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *,
1200 struct fgraph_ops *,
1201 struct ftrace_regs *); /* return */
1202 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *,
1203 struct fgraph_ops *,
1204 struct ftrace_regs *); /* entry */
1205
1206 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace,
1207 struct fgraph_ops *gops,
1208 struct ftrace_regs *fregs);
1209 bool ftrace_pids_enabled(struct ftrace_ops *ops);
1210
1211 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1212
1213 struct fgraph_ops {
1214 trace_func_graph_ent_t entryfunc;
1215 trace_func_graph_ret_t retfunc;
1216 struct ftrace_ops ops; /* for the hash lists */
1217 void *private;
1218 trace_func_graph_ent_t saved_func;
1219 int idx;
1220 };
1221
1222 void *fgraph_reserve_data(int idx, int size_bytes);
1223 void *fgraph_retrieve_data(int idx, int *size_bytes);
1224 void *fgraph_retrieve_parent_data(int idx, int *size_bytes, int depth);
1225
1226 /*
1227 * Stack of return addresses for functions
1228 * of a thread.
1229 * Used in struct thread_info
1230 */
1231 struct ftrace_ret_stack {
1232 unsigned long ret;
1233 unsigned long func;
1234 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
1235 unsigned long fp;
1236 #endif
1237 unsigned long *retp;
1238 };
1239
1240 /*
1241 * Primary handler of a function return.
1242 * It relays on ftrace_return_to_handler.
1243 * Defined in entry_32/64.S
1244 */
1245 extern void return_to_handler(void);
1246
1247 extern int
1248 function_graph_enter_regs(unsigned long ret, unsigned long func,
1249 unsigned long frame_pointer, unsigned long *retp,
1250 struct ftrace_regs *fregs);
1251
function_graph_enter(unsigned long ret,unsigned long func,unsigned long fp,unsigned long * retp)1252 static inline int function_graph_enter(unsigned long ret, unsigned long func,
1253 unsigned long fp, unsigned long *retp)
1254 {
1255 return function_graph_enter_regs(ret, func, fp, retp, NULL);
1256 }
1257
1258 struct ftrace_ret_stack *
1259 ftrace_graph_get_ret_stack(struct task_struct *task, int skip);
1260 unsigned long ftrace_graph_top_ret_addr(struct task_struct *task);
1261
1262 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
1263 unsigned long ret, unsigned long *retp);
1264 unsigned long *fgraph_get_task_var(struct fgraph_ops *gops);
1265
1266 /*
1267 * Sometimes we don't want to trace a function with the function
1268 * graph tracer but we want them to keep traced by the usual function
1269 * tracer if the function graph tracer is not configured.
1270 */
1271 #define __notrace_funcgraph notrace
1272
1273 #define FTRACE_RETFUNC_DEPTH 50
1274 #define FTRACE_RETSTACK_ALLOC_SIZE 32
1275
1276 extern int register_ftrace_graph(struct fgraph_ops *ops);
1277 extern void unregister_ftrace_graph(struct fgraph_ops *ops);
1278
1279 /**
1280 * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
1281 *
1282 * ftrace_graph_stop() is called when a severe error is detected in
1283 * the function graph tracing. This function is called by the critical
1284 * paths of function graph to keep those paths from doing any more harm.
1285 */
1286 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph);
1287
ftrace_graph_is_dead(void)1288 static inline bool ftrace_graph_is_dead(void)
1289 {
1290 return static_branch_unlikely(&kill_ftrace_graph);
1291 }
1292
1293 extern void ftrace_graph_stop(void);
1294
1295 /* The current handlers in use */
1296 extern trace_func_graph_ret_t ftrace_graph_return;
1297 extern trace_func_graph_ent_t ftrace_graph_entry;
1298
1299 extern void ftrace_graph_init_task(struct task_struct *t);
1300 extern void ftrace_graph_exit_task(struct task_struct *t);
1301 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
1302
1303 /* Used by assembly, but to quiet sparse warnings */
1304 extern struct ftrace_ops *function_trace_op;
1305
pause_graph_tracing(void)1306 static inline void pause_graph_tracing(void)
1307 {
1308 atomic_inc(¤t->tracing_graph_pause);
1309 }
1310
unpause_graph_tracing(void)1311 static inline void unpause_graph_tracing(void)
1312 {
1313 atomic_dec(¤t->tracing_graph_pause);
1314 }
1315 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
1316
1317 #define __notrace_funcgraph
1318
ftrace_graph_init_task(struct task_struct * t)1319 static inline void ftrace_graph_init_task(struct task_struct *t) { }
ftrace_graph_exit_task(struct task_struct * t)1320 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
ftrace_graph_init_idle_task(struct task_struct * t,int cpu)1321 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
1322
1323 /* Define as macros as fgraph_ops may not be defined */
1324 #define register_ftrace_graph(ops) ({ -1; })
1325 #define unregister_ftrace_graph(ops) do { } while (0)
1326
1327 static inline unsigned long
ftrace_graph_ret_addr(struct task_struct * task,int * idx,unsigned long ret,unsigned long * retp)1328 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
1329 unsigned long *retp)
1330 {
1331 return ret;
1332 }
1333
pause_graph_tracing(void)1334 static inline void pause_graph_tracing(void) { }
unpause_graph_tracing(void)1335 static inline void unpause_graph_tracing(void) { }
1336 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1337
1338 #ifdef CONFIG_TRACING
1339 enum ftrace_dump_mode;
1340
1341 extern int ftrace_dump_on_oops_enabled(void);
1342
1343 extern void disable_trace_on_warning(void);
1344
1345 #else /* CONFIG_TRACING */
disable_trace_on_warning(void)1346 static inline void disable_trace_on_warning(void) { }
1347 #endif /* CONFIG_TRACING */
1348
1349 #ifdef CONFIG_FTRACE_SYSCALLS
1350
1351 unsigned long arch_syscall_addr(int nr);
1352
1353 #endif /* CONFIG_FTRACE_SYSCALLS */
1354
1355 #endif /* _LINUX_FTRACE_H */
1356