xref: /openbmc/linux/include/linux/ftrace.h (revision c8f05f2f)
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_RETVAL
47 struct fgraph_ret_regs;
48 unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs);
49 #else
50 unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
51 #endif
52 
53 #ifdef CONFIG_FUNCTION_TRACER
54 /*
55  * If the arch's mcount caller does not support all of ftrace's
56  * features, then it must call an indirect function that
57  * does. Or at least does enough to prevent any unwelcome side effects.
58  *
59  * Also define the function prototype that these architectures use
60  * to call the ftrace_ops_list_func().
61  */
62 #if !ARCH_SUPPORTS_FTRACE_OPS
63 # define FTRACE_FORCE_LIST_FUNC 1
64 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
65 #else
66 # define FTRACE_FORCE_LIST_FUNC 0
67 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
68 			       struct ftrace_ops *op, struct ftrace_regs *fregs);
69 #endif
70 extern const struct ftrace_ops ftrace_nop_ops;
71 extern const struct ftrace_ops ftrace_list_ops;
72 struct ftrace_ops *ftrace_find_unique_ops(struct dyn_ftrace *rec);
73 #endif /* CONFIG_FUNCTION_TRACER */
74 
75 /* Main tracing buffer and events set up */
76 #ifdef CONFIG_TRACING
77 void trace_init(void);
78 void early_trace_init(void);
79 #else
trace_init(void)80 static inline void trace_init(void) { }
early_trace_init(void)81 static inline void early_trace_init(void) { }
82 #endif
83 
84 struct module;
85 struct ftrace_hash;
86 struct ftrace_direct_func;
87 
88 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
89 	defined(CONFIG_DYNAMIC_FTRACE)
90 const char *
91 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
92 		   unsigned long *off, char **modname, char *sym);
93 #else
94 static inline const char *
ftrace_mod_address_lookup(unsigned long addr,unsigned long * size,unsigned long * off,char ** modname,char * sym)95 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
96 		   unsigned long *off, char **modname, char *sym)
97 {
98 	return NULL;
99 }
100 #endif
101 
102 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
103 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
104 			   char *type, char *name,
105 			   char *module_name, int *exported);
106 #else
ftrace_mod_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * name,char * module_name,int * exported)107 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
108 					 char *type, char *name,
109 					 char *module_name, int *exported)
110 {
111 	return -1;
112 }
113 #endif
114 
115 #ifdef CONFIG_FUNCTION_TRACER
116 
117 extern int ftrace_enabled;
118 
119 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
120 
121 struct ftrace_regs {
122 	struct pt_regs		regs;
123 };
124 #define arch_ftrace_get_regs(fregs) (&(fregs)->regs)
125 
126 /*
127  * ftrace_regs_set_instruction_pointer() is to be defined by the architecture
128  * if to allow setting of the instruction pointer from the ftrace_regs when
129  * HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports live kernel patching.
130  */
131 #define ftrace_regs_set_instruction_pointer(fregs, ip) do { } while (0)
132 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
133 
ftrace_get_regs(struct ftrace_regs * fregs)134 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
135 {
136 	if (!fregs)
137 		return NULL;
138 
139 	return arch_ftrace_get_regs(fregs);
140 }
141 
142 /*
143  * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs.
144  * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs.
145  */
ftrace_regs_has_args(struct ftrace_regs * fregs)146 static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
147 {
148 	if (IS_ENABLED(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS))
149 		return true;
150 
151 	return ftrace_get_regs(fregs) != NULL;
152 }
153 
154 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
155 #define ftrace_regs_get_instruction_pointer(fregs) \
156 	instruction_pointer(ftrace_get_regs(fregs))
157 #define ftrace_regs_get_argument(fregs, n) \
158 	regs_get_kernel_argument(ftrace_get_regs(fregs), n)
159 #define ftrace_regs_get_stack_pointer(fregs) \
160 	kernel_stack_pointer(ftrace_get_regs(fregs))
161 #define ftrace_regs_return_value(fregs) \
162 	regs_return_value(ftrace_get_regs(fregs))
163 #define ftrace_regs_set_return_value(fregs, ret) \
164 	regs_set_return_value(ftrace_get_regs(fregs), ret)
165 #define ftrace_override_function_with_return(fregs) \
166 	override_function_with_return(ftrace_get_regs(fregs))
167 #define ftrace_regs_query_register_offset(name) \
168 	regs_query_register_offset(name)
169 #endif
170 
171 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
172 			      struct ftrace_ops *op, struct ftrace_regs *fregs);
173 
174 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
175 
176 /*
177  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
178  * set in the flags member.
179  * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
180  * IPMODIFY are a kind of attribute flags which can be set only before
181  * registering the ftrace_ops, and can not be modified while registered.
182  * Changing those attribute flags after registering ftrace_ops will
183  * cause unexpected results.
184  *
185  * ENABLED - set/unset when ftrace_ops is registered/unregistered
186  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
187  *           allocated ftrace_ops which need special care
188  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
189  *            and passed to the callback. If this flag is set, but the
190  *            architecture does not support passing regs
191  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
192  *            ftrace_ops will fail to register, unless the next flag
193  *            is set.
194  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
195  *            handler can handle an arch that does not save regs
196  *            (the handler tests if regs == NULL), then it can set
197  *            this flag instead. It will not fail registering the ftrace_ops
198  *            but, the regs field will be NULL if the arch does not support
199  *            passing regs to the handler.
200  *            Note, if this flag is set, the SAVE_REGS flag will automatically
201  *            get set upon registering the ftrace_ops, if the arch supports it.
202  * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
203  *            that the call back needs recursion protection. If it does
204  *            not set this, then the ftrace infrastructure will assume
205  *            that the callback can handle recursion on its own.
206  * STUB   - The ftrace_ops is just a place holder.
207  * INITIALIZED - The ftrace_ops has already been initialized (first use time
208  *            register_ftrace_function() is called, it will initialized the ops)
209  * DELETED - The ops are being deleted, do not let them be registered again.
210  * ADDING  - The ops is in the process of being added.
211  * REMOVING - The ops is in the process of being removed.
212  * MODIFYING - The ops is in the process of changing its filter functions.
213  * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
214  *            The arch specific code sets this flag when it allocated a
215  *            trampoline. This lets the arch know that it can update the
216  *            trampoline in case the callback function changes.
217  *            The ftrace_ops trampoline can be set by the ftrace users, and
218  *            in such cases the arch must not modify it. Only the arch ftrace
219  *            core code should set this flag.
220  * IPMODIFY - The ops can modify the IP register. This can only be set with
221  *            SAVE_REGS. If another ops with this flag set is already registered
222  *            for any of the functions that this ops will be registered for, then
223  *            this ops will fail to register or set_filter_ip.
224  * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
225  * RCU     - Set when the ops can only be called when RCU is watching.
226  * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
227  * PERMANENT - Set when the ops is permanent and should not be affected by
228  *             ftrace_enabled.
229  * DIRECT - Used by the direct ftrace_ops helper for direct functions
230  *            (internal ftrace only, should not be used by others)
231  */
232 enum {
233 	FTRACE_OPS_FL_ENABLED			= BIT(0),
234 	FTRACE_OPS_FL_DYNAMIC			= BIT(1),
235 	FTRACE_OPS_FL_SAVE_REGS			= BIT(2),
236 	FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED	= BIT(3),
237 	FTRACE_OPS_FL_RECURSION			= BIT(4),
238 	FTRACE_OPS_FL_STUB			= BIT(5),
239 	FTRACE_OPS_FL_INITIALIZED		= BIT(6),
240 	FTRACE_OPS_FL_DELETED			= BIT(7),
241 	FTRACE_OPS_FL_ADDING			= BIT(8),
242 	FTRACE_OPS_FL_REMOVING			= BIT(9),
243 	FTRACE_OPS_FL_MODIFYING			= BIT(10),
244 	FTRACE_OPS_FL_ALLOC_TRAMP		= BIT(11),
245 	FTRACE_OPS_FL_IPMODIFY			= BIT(12),
246 	FTRACE_OPS_FL_PID			= BIT(13),
247 	FTRACE_OPS_FL_RCU			= BIT(14),
248 	FTRACE_OPS_FL_TRACE_ARRAY		= BIT(15),
249 	FTRACE_OPS_FL_PERMANENT                 = BIT(16),
250 	FTRACE_OPS_FL_DIRECT			= BIT(17),
251 };
252 
253 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
254 #define FTRACE_OPS_FL_SAVE_ARGS                        FTRACE_OPS_FL_SAVE_REGS
255 #else
256 #define FTRACE_OPS_FL_SAVE_ARGS                        0
257 #endif
258 
259 /*
260  * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes
261  * to a ftrace_ops. Note, the requests may fail.
262  *
263  * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same
264  *                              function as an ops with IPMODIFY. Called
265  *                              when the DIRECT ops is being registered.
266  *                              This is called with both direct_mutex and
267  *                              ftrace_lock are locked.
268  *
269  * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same
270  *                              function as an ops with IPMODIFY. Called
271  *                              when the other ops (the one with IPMODIFY)
272  *                              is being registered.
273  *                              This is called with direct_mutex locked.
274  *
275  * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same
276  *                               function as an ops with IPMODIFY. Called
277  *                               when the other ops (the one with IPMODIFY)
278  *                               is being unregistered.
279  *                               This is called with direct_mutex locked.
280  */
281 enum ftrace_ops_cmd {
282 	FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF,
283 	FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER,
284 	FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER,
285 };
286 
287 /*
288  * For most ftrace_ops_cmd,
289  * Returns:
290  *        0 - Success.
291  *        Negative on failure. The return value is dependent on the
292  *        callback.
293  */
294 typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd);
295 
296 #ifdef CONFIG_DYNAMIC_FTRACE
297 /* The hash used to know what functions callbacks trace */
298 struct ftrace_ops_hash {
299 	struct ftrace_hash __rcu	*notrace_hash;
300 	struct ftrace_hash __rcu	*filter_hash;
301 	struct mutex			regex_lock;
302 };
303 
304 void ftrace_free_init_mem(void);
305 void ftrace_free_mem(struct module *mod, void *start, void *end);
306 #else
ftrace_free_init_mem(void)307 static inline void ftrace_free_init_mem(void)
308 {
309 	ftrace_boot_snapshot();
310 }
ftrace_free_mem(struct module * mod,void * start,void * end)311 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
312 #endif
313 
314 /*
315  * Note, ftrace_ops can be referenced outside of RCU protection, unless
316  * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
317  * core data, the unregistering of it will perform a scheduling on all CPUs
318  * to make sure that there are no more users. Depending on the load of the
319  * system that may take a bit of time.
320  *
321  * Any private data added must also take care not to be freed and if private
322  * data is added to a ftrace_ops that is in core code, the user of the
323  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
324  */
325 struct ftrace_ops {
326 	ftrace_func_t			func;
327 	struct ftrace_ops __rcu		*next;
328 	unsigned long			flags;
329 	void				*private;
330 	ftrace_func_t			saved_func;
331 #ifdef CONFIG_DYNAMIC_FTRACE
332 	struct ftrace_ops_hash		local_hash;
333 	struct ftrace_ops_hash		*func_hash;
334 	struct ftrace_ops_hash		old_hash;
335 	unsigned long			trampoline;
336 	unsigned long			trampoline_size;
337 	struct list_head		list;
338 	ftrace_ops_func_t		ops_func;
339 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
340 	unsigned long			direct_call;
341 #endif
342 #endif
343 };
344 
345 extern struct ftrace_ops __rcu *ftrace_ops_list;
346 extern struct ftrace_ops ftrace_list_end;
347 
348 /*
349  * Traverse the ftrace_ops_list, invoking all entries.  The reason that we
350  * can use rcu_dereference_raw_check() is that elements removed from this list
351  * are simply leaked, so there is no need to interact with a grace-period
352  * mechanism.  The rcu_dereference_raw_check() calls are needed to handle
353  * concurrent insertions into the ftrace_ops_list.
354  *
355  * Silly Alpha and silly pointer-speculation compiler optimizations!
356  */
357 #define do_for_each_ftrace_op(op, list)			\
358 	op = rcu_dereference_raw_check(list);			\
359 	do
360 
361 /*
362  * Optimized for just a single item in the list (as that is the normal case).
363  */
364 #define while_for_each_ftrace_op(op)				\
365 	while (likely(op = rcu_dereference_raw_check((op)->next)) &&	\
366 	       unlikely((op) != &ftrace_list_end))
367 
368 /*
369  * Type of the current tracing.
370  */
371 enum ftrace_tracing_type_t {
372 	FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
373 	FTRACE_TYPE_RETURN,	/* Hook the return of the function */
374 };
375 
376 /* Current tracing type, default is FTRACE_TYPE_ENTER */
377 extern enum ftrace_tracing_type_t ftrace_tracing_type;
378 
379 /*
380  * The ftrace_ops must be a static and should also
381  * be read_mostly.  These functions do modify read_mostly variables
382  * so use them sparely. Never free an ftrace_op or modify the
383  * next pointer after it has been registered. Even after unregistering
384  * it, the next pointer may still be used internally.
385  */
386 int register_ftrace_function(struct ftrace_ops *ops);
387 int unregister_ftrace_function(struct ftrace_ops *ops);
388 
389 extern void ftrace_stub(unsigned long a0, unsigned long a1,
390 			struct ftrace_ops *op, struct ftrace_regs *fregs);
391 
392 
393 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs);
394 #else /* !CONFIG_FUNCTION_TRACER */
395 /*
396  * (un)register_ftrace_function must be a macro since the ops parameter
397  * must not be evaluated.
398  */
399 #define register_ftrace_function(ops) ({ 0; })
400 #define unregister_ftrace_function(ops) ({ 0; })
ftrace_kill(void)401 static inline void ftrace_kill(void) { }
ftrace_free_init_mem(void)402 static inline void ftrace_free_init_mem(void) { }
ftrace_free_mem(struct module * mod,void * start,void * end)403 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)404 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
405 {
406 	return -EOPNOTSUPP;
407 }
408 #endif /* CONFIG_FUNCTION_TRACER */
409 
410 struct ftrace_func_entry {
411 	struct hlist_node hlist;
412 	unsigned long ip;
413 	unsigned long direct; /* for direct lookup only */
414 };
415 
416 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
417 extern int ftrace_direct_func_count;
418 unsigned long ftrace_find_rec_direct(unsigned long ip);
419 int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
420 int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
421 			     bool free_filters);
422 int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
423 int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr);
424 
425 void ftrace_stub_direct_tramp(void);
426 
427 #else
428 struct ftrace_ops;
429 # define ftrace_direct_func_count 0
ftrace_find_rec_direct(unsigned long ip)430 static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
431 {
432 	return 0;
433 }
register_ftrace_direct(struct ftrace_ops * ops,unsigned long addr)434 static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
435 {
436 	return -ENODEV;
437 }
unregister_ftrace_direct(struct ftrace_ops * ops,unsigned long addr,bool free_filters)438 static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
439 					   bool free_filters)
440 {
441 	return -ENODEV;
442 }
modify_ftrace_direct(struct ftrace_ops * ops,unsigned long addr)443 static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
444 {
445 	return -ENODEV;
446 }
modify_ftrace_direct_nolock(struct ftrace_ops * ops,unsigned long addr)447 static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
448 {
449 	return -ENODEV;
450 }
451 
452 /*
453  * This must be implemented by the architecture.
454  * It is the way the ftrace direct_ops helper, when called
455  * via ftrace (because there's other callbacks besides the
456  * direct call), can inform the architecture's trampoline that this
457  * routine has a direct caller, and what the caller is.
458  *
459  * For example, in x86, it returns the direct caller
460  * callback function via the regs->orig_ax parameter.
461  * Then in the ftrace trampoline, if this is set, it makes
462  * the return from the trampoline jump to the direct caller
463  * instead of going back to the function it just traced.
464  */
arch_ftrace_set_direct_caller(struct ftrace_regs * fregs,unsigned long addr)465 static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
466 						 unsigned long addr) { }
467 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
468 
469 #ifdef CONFIG_STACK_TRACER
470 
471 extern int stack_tracer_enabled;
472 
473 int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
474 		       size_t *lenp, loff_t *ppos);
475 
476 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
477 DECLARE_PER_CPU(int, disable_stack_tracer);
478 
479 /**
480  * stack_tracer_disable - temporarily disable the stack tracer
481  *
482  * There's a few locations (namely in RCU) where stack tracing
483  * cannot be executed. This function is used to disable stack
484  * tracing during those critical sections.
485  *
486  * This function must be called with preemption or interrupts
487  * disabled and stack_tracer_enable() must be called shortly after
488  * while preemption or interrupts are still disabled.
489  */
stack_tracer_disable(void)490 static inline void stack_tracer_disable(void)
491 {
492 	/* Preemption or interrupts must be disabled */
493 	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
494 		WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
495 	this_cpu_inc(disable_stack_tracer);
496 }
497 
498 /**
499  * stack_tracer_enable - re-enable the stack tracer
500  *
501  * After stack_tracer_disable() is called, stack_tracer_enable()
502  * must be called shortly afterward.
503  */
stack_tracer_enable(void)504 static inline void stack_tracer_enable(void)
505 {
506 	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
507 		WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
508 	this_cpu_dec(disable_stack_tracer);
509 }
510 #else
stack_tracer_disable(void)511 static inline void stack_tracer_disable(void) { }
stack_tracer_enable(void)512 static inline void stack_tracer_enable(void) { }
513 #endif
514 
515 #ifdef CONFIG_DYNAMIC_FTRACE
516 
517 void ftrace_arch_code_modify_prepare(void);
518 void ftrace_arch_code_modify_post_process(void);
519 
520 enum ftrace_bug_type {
521 	FTRACE_BUG_UNKNOWN,
522 	FTRACE_BUG_INIT,
523 	FTRACE_BUG_NOP,
524 	FTRACE_BUG_CALL,
525 	FTRACE_BUG_UPDATE,
526 };
527 extern enum ftrace_bug_type ftrace_bug_type;
528 
529 /*
530  * Archs can set this to point to a variable that holds the value that was
531  * expected at the call site before calling ftrace_bug().
532  */
533 extern const void *ftrace_expected;
534 
535 void ftrace_bug(int err, struct dyn_ftrace *rec);
536 
537 struct seq_file;
538 
539 extern int ftrace_text_reserved(const void *start, const void *end);
540 
541 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
542 
543 bool is_ftrace_trampoline(unsigned long addr);
544 
545 /*
546  * The dyn_ftrace record's flags field is split into two parts.
547  * the first part which is '0-FTRACE_REF_MAX' is a counter of
548  * the number of callbacks that have registered the function that
549  * the dyn_ftrace descriptor represents.
550  *
551  * The second part is a mask:
552  *  ENABLED - the function is being traced
553  *  REGS    - the record wants the function to save regs
554  *  REGS_EN - the function is set up to save regs.
555  *  IPMODIFY - the record allows for the IP address to be changed.
556  *  DISABLED - the record is not ready to be touched yet
557  *  DIRECT   - there is a direct function to call
558  *  CALL_OPS - the record can use callsite-specific ops
559  *  CALL_OPS_EN - the function is set up to use callsite-specific ops
560  *  TOUCHED  - A callback was added since boot up
561  *  MODIFIED - The function had IPMODIFY or DIRECT attached to it
562  *
563  * When a new ftrace_ops is registered and wants a function to save
564  * pt_regs, the rec->flags REGS is set. When the function has been
565  * set up to save regs, the REG_EN flag is set. Once a function
566  * starts saving regs it will do so until all ftrace_ops are removed
567  * from tracing that function.
568  */
569 enum {
570 	FTRACE_FL_ENABLED	= (1UL << 31),
571 	FTRACE_FL_REGS		= (1UL << 30),
572 	FTRACE_FL_REGS_EN	= (1UL << 29),
573 	FTRACE_FL_TRAMP		= (1UL << 28),
574 	FTRACE_FL_TRAMP_EN	= (1UL << 27),
575 	FTRACE_FL_IPMODIFY	= (1UL << 26),
576 	FTRACE_FL_DISABLED	= (1UL << 25),
577 	FTRACE_FL_DIRECT	= (1UL << 24),
578 	FTRACE_FL_DIRECT_EN	= (1UL << 23),
579 	FTRACE_FL_CALL_OPS	= (1UL << 22),
580 	FTRACE_FL_CALL_OPS_EN	= (1UL << 21),
581 	FTRACE_FL_TOUCHED	= (1UL << 20),
582 	FTRACE_FL_MODIFIED	= (1UL << 19),
583 };
584 
585 #define FTRACE_REF_MAX_SHIFT	19
586 #define FTRACE_REF_MAX		((1UL << FTRACE_REF_MAX_SHIFT) - 1)
587 
588 #define ftrace_rec_count(rec)	((rec)->flags & FTRACE_REF_MAX)
589 
590 struct dyn_ftrace {
591 	unsigned long		ip; /* address of mcount call-site */
592 	unsigned long		flags;
593 	struct dyn_arch_ftrace	arch;
594 };
595 
596 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
597 			 int remove, int reset);
598 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
599 			  unsigned int cnt, int remove, int reset);
600 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
601 		       int len, int reset);
602 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
603 			int len, int reset);
604 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
605 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
606 void ftrace_free_filter(struct ftrace_ops *ops);
607 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
608 
609 enum {
610 	FTRACE_UPDATE_CALLS		= (1 << 0),
611 	FTRACE_DISABLE_CALLS		= (1 << 1),
612 	FTRACE_UPDATE_TRACE_FUNC	= (1 << 2),
613 	FTRACE_START_FUNC_RET		= (1 << 3),
614 	FTRACE_STOP_FUNC_RET		= (1 << 4),
615 	FTRACE_MAY_SLEEP		= (1 << 5),
616 };
617 
618 /*
619  * The FTRACE_UPDATE_* enum is used to pass information back
620  * from the ftrace_update_record() and ftrace_test_record()
621  * functions. These are called by the code update routines
622  * to find out what is to be done for a given function.
623  *
624  *  IGNORE           - The function is already what we want it to be
625  *  MAKE_CALL        - Start tracing the function
626  *  MODIFY_CALL      - Stop saving regs for the function
627  *  MAKE_NOP         - Stop tracing the function
628  */
629 enum {
630 	FTRACE_UPDATE_IGNORE,
631 	FTRACE_UPDATE_MAKE_CALL,
632 	FTRACE_UPDATE_MODIFY_CALL,
633 	FTRACE_UPDATE_MAKE_NOP,
634 };
635 
636 enum {
637 	FTRACE_ITER_FILTER	= (1 << 0),
638 	FTRACE_ITER_NOTRACE	= (1 << 1),
639 	FTRACE_ITER_PRINTALL	= (1 << 2),
640 	FTRACE_ITER_DO_PROBES	= (1 << 3),
641 	FTRACE_ITER_PROBE	= (1 << 4),
642 	FTRACE_ITER_MOD		= (1 << 5),
643 	FTRACE_ITER_ENABLED	= (1 << 6),
644 	FTRACE_ITER_TOUCHED	= (1 << 7),
645 	FTRACE_ITER_ADDRS	= (1 << 8),
646 };
647 
648 void arch_ftrace_update_code(int command);
649 void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
650 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
651 void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
652 
653 struct ftrace_rec_iter;
654 
655 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
656 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
657 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
658 
659 #define for_ftrace_rec_iter(iter)		\
660 	for (iter = ftrace_rec_iter_start();	\
661 	     iter;				\
662 	     iter = ftrace_rec_iter_next(iter))
663 
664 
665 int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
666 int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
667 void ftrace_run_stop_machine(int command);
668 unsigned long ftrace_location(unsigned long ip);
669 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
670 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
671 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
672 
673 extern ftrace_func_t ftrace_trace_function;
674 
675 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
676 		  struct inode *inode, struct file *file);
677 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
678 			    size_t cnt, loff_t *ppos);
679 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
680 			     size_t cnt, loff_t *ppos);
681 int ftrace_regex_release(struct inode *inode, struct file *file);
682 
683 void __init
684 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
685 
686 /* defined in arch */
687 extern int ftrace_dyn_arch_init(void);
688 extern void ftrace_replace_code(int enable);
689 extern int ftrace_update_ftrace_func(ftrace_func_t func);
690 extern void ftrace_caller(void);
691 extern void ftrace_regs_caller(void);
692 extern void ftrace_call(void);
693 extern void ftrace_regs_call(void);
694 extern void mcount_call(void);
695 
696 void ftrace_modify_all_code(int command);
697 
698 #ifndef FTRACE_ADDR
699 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
700 #endif
701 
702 #ifndef FTRACE_GRAPH_ADDR
703 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
704 #endif
705 
706 #ifndef FTRACE_REGS_ADDR
707 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
708 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
709 #else
710 # define FTRACE_REGS_ADDR FTRACE_ADDR
711 #endif
712 #endif
713 
714 /*
715  * If an arch would like functions that are only traced
716  * by the function graph tracer to jump directly to its own
717  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
718  * to be that address to jump to.
719  */
720 #ifndef FTRACE_GRAPH_TRAMP_ADDR
721 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
722 #endif
723 
724 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
725 extern void ftrace_graph_caller(void);
726 extern int ftrace_enable_ftrace_graph_caller(void);
727 extern int ftrace_disable_ftrace_graph_caller(void);
728 #else
ftrace_enable_ftrace_graph_caller(void)729 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
ftrace_disable_ftrace_graph_caller(void)730 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
731 #endif
732 
733 /**
734  * ftrace_make_nop - convert code into nop
735  * @mod: module structure if called by module load initialization
736  * @rec: the call site record (e.g. mcount/fentry)
737  * @addr: the address that the call site should be calling
738  *
739  * This is a very sensitive operation and great care needs
740  * to be taken by the arch.  The operation should carefully
741  * read the location, check to see if what is read is indeed
742  * what we expect it to be, and then on success of the compare,
743  * it should write to the location.
744  *
745  * The code segment at @rec->ip should be a caller to @addr
746  *
747  * Return must be:
748  *  0 on success
749  *  -EFAULT on error reading the location
750  *  -EINVAL on a failed compare of the contents
751  *  -EPERM  on error writing to the location
752  * Any other value will be considered a failure.
753  */
754 extern int ftrace_make_nop(struct module *mod,
755 			   struct dyn_ftrace *rec, unsigned long addr);
756 
757 /**
758  * ftrace_need_init_nop - return whether nop call sites should be initialized
759  *
760  * Normally the compiler's -mnop-mcount generates suitable nops, so we don't
761  * need to call ftrace_init_nop() if the code is built with that flag.
762  * Architectures where this is not always the case may define their own
763  * condition.
764  *
765  * Return must be:
766  *  0	    if ftrace_init_nop() should be called
767  *  Nonzero if ftrace_init_nop() should not be called
768  */
769 
770 #ifndef ftrace_need_init_nop
771 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT))
772 #endif
773 
774 /**
775  * ftrace_init_nop - initialize a nop call site
776  * @mod: module structure if called by module load initialization
777  * @rec: the call site record (e.g. mcount/fentry)
778  *
779  * This is a very sensitive operation and great care needs
780  * to be taken by the arch.  The operation should carefully
781  * read the location, check to see if what is read is indeed
782  * what we expect it to be, and then on success of the compare,
783  * it should write to the location.
784  *
785  * The code segment at @rec->ip should contain the contents created by
786  * the compiler
787  *
788  * Return must be:
789  *  0 on success
790  *  -EFAULT on error reading the location
791  *  -EINVAL on a failed compare of the contents
792  *  -EPERM  on error writing to the location
793  * Any other value will be considered a failure.
794  */
795 #ifndef ftrace_init_nop
ftrace_init_nop(struct module * mod,struct dyn_ftrace * rec)796 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
797 {
798 	return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
799 }
800 #endif
801 
802 /**
803  * ftrace_make_call - convert a nop call site into a call to addr
804  * @rec: the call site record (e.g. mcount/fentry)
805  * @addr: the address that the call site should call
806  *
807  * This is a very sensitive operation and great care needs
808  * to be taken by the arch.  The operation should carefully
809  * read the location, check to see if what is read is indeed
810  * what we expect it to be, and then on success of the compare,
811  * it should write to the location.
812  *
813  * The code segment at @rec->ip should be a nop
814  *
815  * Return must be:
816  *  0 on success
817  *  -EFAULT on error reading the location
818  *  -EINVAL on a failed compare of the contents
819  *  -EPERM  on error writing to the location
820  * Any other value will be considered a failure.
821  */
822 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
823 
824 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) || \
825 	defined(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS)
826 /**
827  * ftrace_modify_call - convert from one addr to another (no nop)
828  * @rec: the call site record (e.g. mcount/fentry)
829  * @old_addr: the address expected to be currently called to
830  * @addr: the address to change to
831  *
832  * This is a very sensitive operation and great care needs
833  * to be taken by the arch.  The operation should carefully
834  * read the location, check to see if what is read is indeed
835  * what we expect it to be, and then on success of the compare,
836  * it should write to the location.
837  *
838  * When using call ops, this is called when the associated ops change, even
839  * when (addr == old_addr).
840  *
841  * The code segment at @rec->ip should be a caller to @old_addr
842  *
843  * Return must be:
844  *  0 on success
845  *  -EFAULT on error reading the location
846  *  -EINVAL on a failed compare of the contents
847  *  -EPERM  on error writing to the location
848  * Any other value will be considered a failure.
849  */
850 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
851 			      unsigned long addr);
852 #else
853 /* Should never be called */
ftrace_modify_call(struct dyn_ftrace * rec,unsigned long old_addr,unsigned long addr)854 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
855 				     unsigned long addr)
856 {
857 	return -EINVAL;
858 }
859 #endif
860 
861 extern int skip_trace(unsigned long ip);
862 extern void ftrace_module_init(struct module *mod);
863 extern void ftrace_module_enable(struct module *mod);
864 extern void ftrace_release_mod(struct module *mod);
865 #else /* CONFIG_DYNAMIC_FTRACE */
skip_trace(unsigned long ip)866 static inline int skip_trace(unsigned long ip) { return 0; }
ftrace_module_init(struct module * mod)867 static inline void ftrace_module_init(struct module *mod) { }
ftrace_module_enable(struct module * mod)868 static inline void ftrace_module_enable(struct module *mod) { }
ftrace_release_mod(struct module * mod)869 static inline void ftrace_release_mod(struct module *mod) { }
ftrace_text_reserved(const void * start,const void * end)870 static inline int ftrace_text_reserved(const void *start, const void *end)
871 {
872 	return 0;
873 }
ftrace_location(unsigned long ip)874 static inline unsigned long ftrace_location(unsigned long ip)
875 {
876 	return 0;
877 }
878 
879 /*
880  * Again users of functions that have ftrace_ops may not
881  * have them defined when ftrace is not enabled, but these
882  * functions may still be called. Use a macro instead of inline.
883  */
884 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
885 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
886 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
887 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; })
888 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
889 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
890 #define ftrace_free_filter(ops) do { } while (0)
891 #define ftrace_ops_set_global_filter(ops) do { } while (0)
892 
ftrace_filter_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)893 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
894 			    size_t cnt, loff_t *ppos) { return -ENODEV; }
ftrace_notrace_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)895 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
896 			     size_t cnt, loff_t *ppos) { return -ENODEV; }
897 static inline int
ftrace_regex_release(struct inode * inode,struct file * file)898 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
899 
is_ftrace_trampoline(unsigned long addr)900 static inline bool is_ftrace_trampoline(unsigned long addr)
901 {
902 	return false;
903 }
904 #endif /* CONFIG_DYNAMIC_FTRACE */
905 
906 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
907 #ifndef ftrace_graph_func
908 #define ftrace_graph_func ftrace_stub
909 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB
910 #else
911 #define FTRACE_OPS_GRAPH_STUB 0
912 #endif
913 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
914 
915 /* totally disable ftrace - can not re-enable after this */
916 void ftrace_kill(void);
917 
tracer_disable(void)918 static inline void tracer_disable(void)
919 {
920 #ifdef CONFIG_FUNCTION_TRACER
921 	ftrace_enabled = 0;
922 #endif
923 }
924 
925 /*
926  * Ftrace disable/restore without lock. Some synchronization mechanism
927  * must be used to prevent ftrace_enabled to be changed between
928  * disable/restore.
929  */
__ftrace_enabled_save(void)930 static inline int __ftrace_enabled_save(void)
931 {
932 #ifdef CONFIG_FUNCTION_TRACER
933 	int saved_ftrace_enabled = ftrace_enabled;
934 	ftrace_enabled = 0;
935 	return saved_ftrace_enabled;
936 #else
937 	return 0;
938 #endif
939 }
940 
__ftrace_enabled_restore(int enabled)941 static inline void __ftrace_enabled_restore(int enabled)
942 {
943 #ifdef CONFIG_FUNCTION_TRACER
944 	ftrace_enabled = enabled;
945 #endif
946 }
947 
948 /* All archs should have this, but we define it for consistency */
949 #ifndef ftrace_return_address0
950 # define ftrace_return_address0 __builtin_return_address(0)
951 #endif
952 
953 /* Archs may use other ways for ADDR1 and beyond */
954 #ifndef ftrace_return_address
955 # ifdef CONFIG_FRAME_POINTER
956 #  define ftrace_return_address(n) __builtin_return_address(n)
957 # else
958 #  define ftrace_return_address(n) 0UL
959 # endif
960 #endif
961 
962 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
963 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
964 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
965 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
966 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
967 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
968 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
969 
get_lock_parent_ip(void)970 static __always_inline unsigned long get_lock_parent_ip(void)
971 {
972 	unsigned long addr = CALLER_ADDR0;
973 
974 	if (!in_lock_functions(addr))
975 		return addr;
976 	addr = CALLER_ADDR1;
977 	if (!in_lock_functions(addr))
978 		return addr;
979 	return CALLER_ADDR2;
980 }
981 
982 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
983   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
984   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
985 #else
986 /*
987  * Use defines instead of static inlines because some arches will make code out
988  * of the CALLER_ADDR, when we really want these to be a real nop.
989  */
990 # define trace_preempt_on(a0, a1) do { } while (0)
991 # define trace_preempt_off(a0, a1) do { } while (0)
992 #endif
993 
994 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
995 extern void ftrace_init(void);
996 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
997 #define FTRACE_CALLSITE_SECTION	"__patchable_function_entries"
998 #else
999 #define FTRACE_CALLSITE_SECTION	"__mcount_loc"
1000 #endif
1001 #else
ftrace_init(void)1002 static inline void ftrace_init(void) { }
1003 #endif
1004 
1005 /*
1006  * Structure that defines an entry function trace.
1007  * It's already packed but the attribute "packed" is needed
1008  * to remove extra padding at the end.
1009  */
1010 struct ftrace_graph_ent {
1011 	unsigned long func; /* Current function */
1012 	int depth;
1013 } __packed;
1014 
1015 /*
1016  * Structure that defines a return function trace.
1017  * It's already packed but the attribute "packed" is needed
1018  * to remove extra padding at the end.
1019  */
1020 struct ftrace_graph_ret {
1021 	unsigned long func; /* Current function */
1022 #ifdef CONFIG_FUNCTION_GRAPH_RETVAL
1023 	unsigned long retval;
1024 #endif
1025 	int depth;
1026 	/* Number of functions that overran the depth limit for current task */
1027 	unsigned int overrun;
1028 	unsigned long long calltime;
1029 	unsigned long long rettime;
1030 } __packed;
1031 
1032 /* Type of the callback handlers for tracing function graph*/
1033 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
1034 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
1035 
1036 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
1037 
1038 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1039 
1040 struct fgraph_ops {
1041 	trace_func_graph_ent_t		entryfunc;
1042 	trace_func_graph_ret_t		retfunc;
1043 };
1044 
1045 /*
1046  * Stack of return addresses for functions
1047  * of a thread.
1048  * Used in struct thread_info
1049  */
1050 struct ftrace_ret_stack {
1051 	unsigned long ret;
1052 	unsigned long func;
1053 	unsigned long long calltime;
1054 #ifdef CONFIG_FUNCTION_PROFILER
1055 	unsigned long long subtime;
1056 #endif
1057 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
1058 	unsigned long fp;
1059 #endif
1060 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
1061 	unsigned long *retp;
1062 #endif
1063 };
1064 
1065 /*
1066  * Primary handler of a function return.
1067  * It relays on ftrace_return_to_handler.
1068  * Defined in entry_32/64.S
1069  */
1070 extern void return_to_handler(void);
1071 
1072 extern int
1073 function_graph_enter(unsigned long ret, unsigned long func,
1074 		     unsigned long frame_pointer, unsigned long *retp);
1075 
1076 struct ftrace_ret_stack *
1077 ftrace_graph_get_ret_stack(struct task_struct *task, int idx);
1078 
1079 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
1080 				    unsigned long ret, unsigned long *retp);
1081 
1082 /*
1083  * Sometimes we don't want to trace a function with the function
1084  * graph tracer but we want them to keep traced by the usual function
1085  * tracer if the function graph tracer is not configured.
1086  */
1087 #define __notrace_funcgraph		notrace
1088 
1089 #define FTRACE_RETFUNC_DEPTH 50
1090 #define FTRACE_RETSTACK_ALLOC_SIZE 32
1091 
1092 extern int register_ftrace_graph(struct fgraph_ops *ops);
1093 extern void unregister_ftrace_graph(struct fgraph_ops *ops);
1094 
1095 /**
1096  * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
1097  *
1098  * ftrace_graph_stop() is called when a severe error is detected in
1099  * the function graph tracing. This function is called by the critical
1100  * paths of function graph to keep those paths from doing any more harm.
1101  */
1102 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph);
1103 
ftrace_graph_is_dead(void)1104 static inline bool ftrace_graph_is_dead(void)
1105 {
1106 	return static_branch_unlikely(&kill_ftrace_graph);
1107 }
1108 
1109 extern void ftrace_graph_stop(void);
1110 
1111 /* The current handlers in use */
1112 extern trace_func_graph_ret_t ftrace_graph_return;
1113 extern trace_func_graph_ent_t ftrace_graph_entry;
1114 
1115 extern void ftrace_graph_init_task(struct task_struct *t);
1116 extern void ftrace_graph_exit_task(struct task_struct *t);
1117 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
1118 
pause_graph_tracing(void)1119 static inline void pause_graph_tracing(void)
1120 {
1121 	atomic_inc(&current->tracing_graph_pause);
1122 }
1123 
unpause_graph_tracing(void)1124 static inline void unpause_graph_tracing(void)
1125 {
1126 	atomic_dec(&current->tracing_graph_pause);
1127 }
1128 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
1129 
1130 #define __notrace_funcgraph
1131 
ftrace_graph_init_task(struct task_struct * t)1132 static inline void ftrace_graph_init_task(struct task_struct *t) { }
ftrace_graph_exit_task(struct task_struct * t)1133 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
ftrace_graph_init_idle_task(struct task_struct * t,int cpu)1134 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
1135 
1136 /* Define as macros as fgraph_ops may not be defined */
1137 #define register_ftrace_graph(ops) ({ -1; })
1138 #define unregister_ftrace_graph(ops) do { } while (0)
1139 
1140 static inline unsigned long
ftrace_graph_ret_addr(struct task_struct * task,int * idx,unsigned long ret,unsigned long * retp)1141 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
1142 		      unsigned long *retp)
1143 {
1144 	return ret;
1145 }
1146 
pause_graph_tracing(void)1147 static inline void pause_graph_tracing(void) { }
unpause_graph_tracing(void)1148 static inline void unpause_graph_tracing(void) { }
1149 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1150 
1151 #ifdef CONFIG_TRACING
1152 enum ftrace_dump_mode;
1153 
1154 extern enum ftrace_dump_mode ftrace_dump_on_oops;
1155 extern int tracepoint_printk;
1156 
1157 extern void disable_trace_on_warning(void);
1158 extern int __disable_trace_on_warning;
1159 
1160 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
1161 			     void *buffer, size_t *lenp, loff_t *ppos);
1162 
1163 #else /* CONFIG_TRACING */
disable_trace_on_warning(void)1164 static inline void  disable_trace_on_warning(void) { }
1165 #endif /* CONFIG_TRACING */
1166 
1167 #ifdef CONFIG_FTRACE_SYSCALLS
1168 
1169 unsigned long arch_syscall_addr(int nr);
1170 
1171 #endif /* CONFIG_FTRACE_SYSCALLS */
1172 
1173 #endif /* _LINUX_FTRACE_H */
1174