1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Ftrace header. For implementation details beyond the random comments
4 * scattered below, see: Documentation/trace/ftrace-design.rst
7 #ifndef _LINUX_FTRACE_H
8 #define _LINUX_FTRACE_H
10 #include <linux/trace_recursion.h>
11 #include <linux/trace_clock.h>
12 #include <linux/kallsyms.h>
13 #include <linux/linkage.h>
14 #include <linux/bitops.h>
15 #include <linux/ptrace.h>
16 #include <linux/ktime.h>
17 #include <linux/sched.h>
18 #include <linux/types.h>
19 #include <linux/init.h>
22 #include <asm/ftrace.h>
25 * If the arch supports passing the variable contents of
26 * function_trace_op as the third parameter back from the
27 * mcount call, then the arch should define this as 1.
29 #ifndef ARCH_SUPPORTS_FTRACE_OPS
30 #define ARCH_SUPPORTS_FTRACE_OPS 0
33 #ifdef CONFIG_FUNCTION_TRACER
37 * If the arch's mcount caller does not support all of ftrace's
38 * features, then it must call an indirect function that
39 * does. Or at least does enough to prevent any unwelcome side effects.
41 * Also define the function prototype that these architectures use
42 * to call the ftrace_ops_list_func().
44 #if !ARCH_SUPPORTS_FTRACE_OPS
45 # define FTRACE_FORCE_LIST_FUNC 1
46 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
48 # define FTRACE_FORCE_LIST_FUNC 0
49 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
50 struct ftrace_ops *op, struct ftrace_regs *fregs);
52 #endif /* CONFIG_FUNCTION_TRACER */
54 /* Main tracing buffer and events set up */
56 void trace_init(void);
57 void early_trace_init(void);
59 static inline void trace_init(void) { }
60 static inline void early_trace_init(void) { }
65 struct ftrace_direct_func;
67 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
68 defined(CONFIG_DYNAMIC_FTRACE)
70 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
71 unsigned long *off, char **modname, char *sym);
73 static inline const char *
74 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
75 unsigned long *off, char **modname, char *sym)
81 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
82 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
83 char *type, char *name,
84 char *module_name, int *exported);
86 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
87 char *type, char *name,
88 char *module_name, int *exported)
94 #ifdef CONFIG_FUNCTION_TRACER
96 extern int ftrace_enabled;
98 ftrace_enable_sysctl(struct ctl_table *table, int write,
99 void *buffer, size_t *lenp, loff_t *ppos);
101 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
106 #define arch_ftrace_get_regs(fregs) (&(fregs)->regs)
109 * ftrace_instruction_pointer_set() is to be defined by the architecture
110 * if to allow setting of the instruction pointer from the ftrace_regs
111 * when HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports
112 * live kernel patching.
114 #define ftrace_instruction_pointer_set(fregs, ip) do { } while (0)
115 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
117 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
122 return arch_ftrace_get_regs(fregs);
125 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
126 struct ftrace_ops *op, struct ftrace_regs *fregs);
128 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
131 * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
132 * set in the flags member.
133 * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
134 * IPMODIFY are a kind of attribute flags which can be set only before
135 * registering the ftrace_ops, and can not be modified while registered.
136 * Changing those attribute flags after registering ftrace_ops will
137 * cause unexpected results.
139 * ENABLED - set/unset when ftrace_ops is registered/unregistered
140 * DYNAMIC - set when ftrace_ops is registered to denote dynamically
141 * allocated ftrace_ops which need special care
142 * SAVE_REGS - The ftrace_ops wants regs saved at each function called
143 * and passed to the callback. If this flag is set, but the
144 * architecture does not support passing regs
145 * (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
146 * ftrace_ops will fail to register, unless the next flag
148 * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
149 * handler can handle an arch that does not save regs
150 * (the handler tests if regs == NULL), then it can set
151 * this flag instead. It will not fail registering the ftrace_ops
152 * but, the regs field will be NULL if the arch does not support
153 * passing regs to the handler.
154 * Note, if this flag is set, the SAVE_REGS flag will automatically
155 * get set upon registering the ftrace_ops, if the arch supports it.
156 * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
157 * that the call back needs recursion protection. If it does
158 * not set this, then the ftrace infrastructure will assume
159 * that the callback can handle recursion on its own.
160 * STUB - The ftrace_ops is just a place holder.
161 * INITIALIZED - The ftrace_ops has already been initialized (first use time
162 * register_ftrace_function() is called, it will initialized the ops)
163 * DELETED - The ops are being deleted, do not let them be registered again.
164 * ADDING - The ops is in the process of being added.
165 * REMOVING - The ops is in the process of being removed.
166 * MODIFYING - The ops is in the process of changing its filter functions.
167 * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
168 * The arch specific code sets this flag when it allocated a
169 * trampoline. This lets the arch know that it can update the
170 * trampoline in case the callback function changes.
171 * The ftrace_ops trampoline can be set by the ftrace users, and
172 * in such cases the arch must not modify it. Only the arch ftrace
173 * core code should set this flag.
174 * IPMODIFY - The ops can modify the IP register. This can only be set with
175 * SAVE_REGS. If another ops with this flag set is already registered
176 * for any of the functions that this ops will be registered for, then
177 * this ops will fail to register or set_filter_ip.
178 * PID - Is affected by set_ftrace_pid (allows filtering on those pids)
179 * RCU - Set when the ops can only be called when RCU is watching.
180 * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
181 * PERMANENT - Set when the ops is permanent and should not be affected by
183 * DIRECT - Used by the direct ftrace_ops helper for direct functions
184 * (internal ftrace only, should not be used by others)
187 FTRACE_OPS_FL_ENABLED = BIT(0),
188 FTRACE_OPS_FL_DYNAMIC = BIT(1),
189 FTRACE_OPS_FL_SAVE_REGS = BIT(2),
190 FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3),
191 FTRACE_OPS_FL_RECURSION = BIT(4),
192 FTRACE_OPS_FL_STUB = BIT(5),
193 FTRACE_OPS_FL_INITIALIZED = BIT(6),
194 FTRACE_OPS_FL_DELETED = BIT(7),
195 FTRACE_OPS_FL_ADDING = BIT(8),
196 FTRACE_OPS_FL_REMOVING = BIT(9),
197 FTRACE_OPS_FL_MODIFYING = BIT(10),
198 FTRACE_OPS_FL_ALLOC_TRAMP = BIT(11),
199 FTRACE_OPS_FL_IPMODIFY = BIT(12),
200 FTRACE_OPS_FL_PID = BIT(13),
201 FTRACE_OPS_FL_RCU = BIT(14),
202 FTRACE_OPS_FL_TRACE_ARRAY = BIT(15),
203 FTRACE_OPS_FL_PERMANENT = BIT(16),
204 FTRACE_OPS_FL_DIRECT = BIT(17),
207 #ifdef CONFIG_DYNAMIC_FTRACE
208 /* The hash used to know what functions callbacks trace */
209 struct ftrace_ops_hash {
210 struct ftrace_hash __rcu *notrace_hash;
211 struct ftrace_hash __rcu *filter_hash;
212 struct mutex regex_lock;
215 void ftrace_free_init_mem(void);
216 void ftrace_free_mem(struct module *mod, void *start, void *end);
218 static inline void ftrace_free_init_mem(void) { }
219 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
223 * Note, ftrace_ops can be referenced outside of RCU protection, unless
224 * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
225 * core data, the unregistering of it will perform a scheduling on all CPUs
226 * to make sure that there are no more users. Depending on the load of the
227 * system that may take a bit of time.
229 * Any private data added must also take care not to be freed and if private
230 * data is added to a ftrace_ops that is in core code, the user of the
231 * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
235 struct ftrace_ops __rcu *next;
238 ftrace_func_t saved_func;
239 #ifdef CONFIG_DYNAMIC_FTRACE
240 struct ftrace_ops_hash local_hash;
241 struct ftrace_ops_hash *func_hash;
242 struct ftrace_ops_hash old_hash;
243 unsigned long trampoline;
244 unsigned long trampoline_size;
245 struct list_head list;
249 extern struct ftrace_ops __rcu *ftrace_ops_list;
250 extern struct ftrace_ops ftrace_list_end;
253 * Traverse the ftrace_ops_list, invoking all entries. The reason that we
254 * can use rcu_dereference_raw_check() is that elements removed from this list
255 * are simply leaked, so there is no need to interact with a grace-period
256 * mechanism. The rcu_dereference_raw_check() calls are needed to handle
257 * concurrent insertions into the ftrace_ops_list.
259 * Silly Alpha and silly pointer-speculation compiler optimizations!
261 #define do_for_each_ftrace_op(op, list) \
262 op = rcu_dereference_raw_check(list); \
266 * Optimized for just a single item in the list (as that is the normal case).
268 #define while_for_each_ftrace_op(op) \
269 while (likely(op = rcu_dereference_raw_check((op)->next)) && \
270 unlikely((op) != &ftrace_list_end))
273 * Type of the current tracing.
275 enum ftrace_tracing_type_t {
276 FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
277 FTRACE_TYPE_RETURN, /* Hook the return of the function */
280 /* Current tracing type, default is FTRACE_TYPE_ENTER */
281 extern enum ftrace_tracing_type_t ftrace_tracing_type;
284 * The ftrace_ops must be a static and should also
285 * be read_mostly. These functions do modify read_mostly variables
286 * so use them sparely. Never free an ftrace_op or modify the
287 * next pointer after it has been registered. Even after unregistering
288 * it, the next pointer may still be used internally.
290 int register_ftrace_function(struct ftrace_ops *ops);
291 int unregister_ftrace_function(struct ftrace_ops *ops);
293 extern void ftrace_stub(unsigned long a0, unsigned long a1,
294 struct ftrace_ops *op, struct ftrace_regs *fregs);
296 #else /* !CONFIG_FUNCTION_TRACER */
298 * (un)register_ftrace_function must be a macro since the ops parameter
299 * must not be evaluated.
301 #define register_ftrace_function(ops) ({ 0; })
302 #define unregister_ftrace_function(ops) ({ 0; })
303 static inline void ftrace_kill(void) { }
304 static inline void ftrace_free_init_mem(void) { }
305 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
306 #endif /* CONFIG_FUNCTION_TRACER */
308 struct ftrace_func_entry {
309 struct hlist_node hlist;
311 unsigned long direct; /* for direct lookup only */
316 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
317 extern int ftrace_direct_func_count;
318 int register_ftrace_direct(unsigned long ip, unsigned long addr);
319 int unregister_ftrace_direct(unsigned long ip, unsigned long addr);
320 int modify_ftrace_direct(unsigned long ip, unsigned long old_addr, unsigned long new_addr);
321 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr);
322 int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
323 struct dyn_ftrace *rec,
324 unsigned long old_addr,
325 unsigned long new_addr);
326 unsigned long ftrace_find_rec_direct(unsigned long ip);
328 # define ftrace_direct_func_count 0
329 static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
333 static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
337 static inline int modify_ftrace_direct(unsigned long ip,
338 unsigned long old_addr, unsigned long new_addr)
342 static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
346 static inline int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
347 struct dyn_ftrace *rec,
348 unsigned long old_addr,
349 unsigned long new_addr)
353 static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
357 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
359 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
361 * This must be implemented by the architecture.
362 * It is the way the ftrace direct_ops helper, when called
363 * via ftrace (because there's other callbacks besides the
364 * direct call), can inform the architecture's trampoline that this
365 * routine has a direct caller, and what the caller is.
367 * For example, in x86, it returns the direct caller
368 * callback function via the regs->orig_ax parameter.
369 * Then in the ftrace trampoline, if this is set, it makes
370 * the return from the trampoline jump to the direct caller
371 * instead of going back to the function it just traced.
373 static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs,
374 unsigned long addr) { }
375 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
377 #ifdef CONFIG_STACK_TRACER
379 extern int stack_tracer_enabled;
381 int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
382 size_t *lenp, loff_t *ppos);
384 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
385 DECLARE_PER_CPU(int, disable_stack_tracer);
388 * stack_tracer_disable - temporarily disable the stack tracer
390 * There's a few locations (namely in RCU) where stack tracing
391 * cannot be executed. This function is used to disable stack
392 * tracing during those critical sections.
394 * This function must be called with preemption or interrupts
395 * disabled and stack_tracer_enable() must be called shortly after
396 * while preemption or interrupts are still disabled.
398 static inline void stack_tracer_disable(void)
400 /* Preemption or interrupts must be disabled */
401 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
402 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
403 this_cpu_inc(disable_stack_tracer);
407 * stack_tracer_enable - re-enable the stack tracer
409 * After stack_tracer_disable() is called, stack_tracer_enable()
410 * must be called shortly afterward.
412 static inline void stack_tracer_enable(void)
414 if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
415 WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
416 this_cpu_dec(disable_stack_tracer);
419 static inline void stack_tracer_disable(void) { }
420 static inline void stack_tracer_enable(void) { }
423 #ifdef CONFIG_DYNAMIC_FTRACE
425 int ftrace_arch_code_modify_prepare(void);
426 int ftrace_arch_code_modify_post_process(void);
428 enum ftrace_bug_type {
435 extern enum ftrace_bug_type ftrace_bug_type;
438 * Archs can set this to point to a variable that holds the value that was
439 * expected at the call site before calling ftrace_bug().
441 extern const void *ftrace_expected;
443 void ftrace_bug(int err, struct dyn_ftrace *rec);
447 extern int ftrace_text_reserved(const void *start, const void *end);
449 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
451 bool is_ftrace_trampoline(unsigned long addr);
454 * The dyn_ftrace record's flags field is split into two parts.
455 * the first part which is '0-FTRACE_REF_MAX' is a counter of
456 * the number of callbacks that have registered the function that
457 * the dyn_ftrace descriptor represents.
459 * The second part is a mask:
460 * ENABLED - the function is being traced
461 * REGS - the record wants the function to save regs
462 * REGS_EN - the function is set up to save regs.
463 * IPMODIFY - the record allows for the IP address to be changed.
464 * DISABLED - the record is not ready to be touched yet
465 * DIRECT - there is a direct function to call
467 * When a new ftrace_ops is registered and wants a function to save
468 * pt_regs, the rec->flags REGS is set. When the function has been
469 * set up to save regs, the REG_EN flag is set. Once a function
470 * starts saving regs it will do so until all ftrace_ops are removed
471 * from tracing that function.
474 FTRACE_FL_ENABLED = (1UL << 31),
475 FTRACE_FL_REGS = (1UL << 30),
476 FTRACE_FL_REGS_EN = (1UL << 29),
477 FTRACE_FL_TRAMP = (1UL << 28),
478 FTRACE_FL_TRAMP_EN = (1UL << 27),
479 FTRACE_FL_IPMODIFY = (1UL << 26),
480 FTRACE_FL_DISABLED = (1UL << 25),
481 FTRACE_FL_DIRECT = (1UL << 24),
482 FTRACE_FL_DIRECT_EN = (1UL << 23),
485 #define FTRACE_REF_MAX_SHIFT 23
486 #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
488 #define ftrace_rec_count(rec) ((rec)->flags & FTRACE_REF_MAX)
491 unsigned long ip; /* address of mcount call-site */
493 struct dyn_arch_ftrace arch;
496 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
497 int remove, int reset);
498 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
500 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
502 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
503 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
504 void ftrace_free_filter(struct ftrace_ops *ops);
505 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
508 FTRACE_UPDATE_CALLS = (1 << 0),
509 FTRACE_DISABLE_CALLS = (1 << 1),
510 FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
511 FTRACE_START_FUNC_RET = (1 << 3),
512 FTRACE_STOP_FUNC_RET = (1 << 4),
513 FTRACE_MAY_SLEEP = (1 << 5),
517 * The FTRACE_UPDATE_* enum is used to pass information back
518 * from the ftrace_update_record() and ftrace_test_record()
519 * functions. These are called by the code update routines
520 * to find out what is to be done for a given function.
522 * IGNORE - The function is already what we want it to be
523 * MAKE_CALL - Start tracing the function
524 * MODIFY_CALL - Stop saving regs for the function
525 * MAKE_NOP - Stop tracing the function
528 FTRACE_UPDATE_IGNORE,
529 FTRACE_UPDATE_MAKE_CALL,
530 FTRACE_UPDATE_MODIFY_CALL,
531 FTRACE_UPDATE_MAKE_NOP,
535 FTRACE_ITER_FILTER = (1 << 0),
536 FTRACE_ITER_NOTRACE = (1 << 1),
537 FTRACE_ITER_PRINTALL = (1 << 2),
538 FTRACE_ITER_DO_PROBES = (1 << 3),
539 FTRACE_ITER_PROBE = (1 << 4),
540 FTRACE_ITER_MOD = (1 << 5),
541 FTRACE_ITER_ENABLED = (1 << 6),
544 void arch_ftrace_update_code(int command);
545 void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
546 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
547 void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
549 struct ftrace_rec_iter;
551 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
552 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
553 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
555 #define for_ftrace_rec_iter(iter) \
556 for (iter = ftrace_rec_iter_start(); \
558 iter = ftrace_rec_iter_next(iter))
561 int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
562 int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
563 void ftrace_run_stop_machine(int command);
564 unsigned long ftrace_location(unsigned long ip);
565 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
566 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
567 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
569 extern ftrace_func_t ftrace_trace_function;
571 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
572 struct inode *inode, struct file *file);
573 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
574 size_t cnt, loff_t *ppos);
575 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
576 size_t cnt, loff_t *ppos);
577 int ftrace_regex_release(struct inode *inode, struct file *file);
580 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
582 /* defined in arch */
583 extern int ftrace_ip_converted(unsigned long ip);
584 extern int ftrace_dyn_arch_init(void);
585 extern void ftrace_replace_code(int enable);
586 extern int ftrace_update_ftrace_func(ftrace_func_t func);
587 extern void ftrace_caller(void);
588 extern void ftrace_regs_caller(void);
589 extern void ftrace_call(void);
590 extern void ftrace_regs_call(void);
591 extern void mcount_call(void);
593 void ftrace_modify_all_code(int command);
596 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
599 #ifndef FTRACE_GRAPH_ADDR
600 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
603 #ifndef FTRACE_REGS_ADDR
604 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
605 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
607 # define FTRACE_REGS_ADDR FTRACE_ADDR
612 * If an arch would like functions that are only traced
613 * by the function graph tracer to jump directly to its own
614 * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
615 * to be that address to jump to.
617 #ifndef FTRACE_GRAPH_TRAMP_ADDR
618 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
621 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
622 extern void ftrace_graph_caller(void);
623 extern int ftrace_enable_ftrace_graph_caller(void);
624 extern int ftrace_disable_ftrace_graph_caller(void);
626 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
627 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
631 * ftrace_make_nop - convert code into nop
632 * @mod: module structure if called by module load initialization
633 * @rec: the call site record (e.g. mcount/fentry)
634 * @addr: the address that the call site should be calling
636 * This is a very sensitive operation and great care needs
637 * to be taken by the arch. The operation should carefully
638 * read the location, check to see if what is read is indeed
639 * what we expect it to be, and then on success of the compare,
640 * it should write to the location.
642 * The code segment at @rec->ip should be a caller to @addr
646 * -EFAULT on error reading the location
647 * -EINVAL on a failed compare of the contents
648 * -EPERM on error writing to the location
649 * Any other value will be considered a failure.
651 extern int ftrace_make_nop(struct module *mod,
652 struct dyn_ftrace *rec, unsigned long addr);
655 * ftrace_need_init_nop - return whether nop call sites should be initialized
657 * Normally the compiler's -mnop-mcount generates suitable nops, so we don't
658 * need to call ftrace_init_nop() if the code is built with that flag.
659 * Architectures where this is not always the case may define their own
663 * 0 if ftrace_init_nop() should be called
664 * Nonzero if ftrace_init_nop() should not be called
667 #ifndef ftrace_need_init_nop
668 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT))
672 * ftrace_init_nop - initialize a nop call site
673 * @mod: module structure if called by module load initialization
674 * @rec: the call site record (e.g. mcount/fentry)
676 * This is a very sensitive operation and great care needs
677 * to be taken by the arch. The operation should carefully
678 * read the location, check to see if what is read is indeed
679 * what we expect it to be, and then on success of the compare,
680 * it should write to the location.
682 * The code segment at @rec->ip should contain the contents created by
687 * -EFAULT on error reading the location
688 * -EINVAL on a failed compare of the contents
689 * -EPERM on error writing to the location
690 * Any other value will be considered a failure.
692 #ifndef ftrace_init_nop
693 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
695 return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
700 * ftrace_make_call - convert a nop call site into a call to addr
701 * @rec: the call site record (e.g. mcount/fentry)
702 * @addr: the address that the call site should call
704 * This is a very sensitive operation and great care needs
705 * to be taken by the arch. The operation should carefully
706 * read the location, check to see if what is read is indeed
707 * what we expect it to be, and then on success of the compare,
708 * it should write to the location.
710 * The code segment at @rec->ip should be a nop
714 * -EFAULT on error reading the location
715 * -EINVAL on a failed compare of the contents
716 * -EPERM on error writing to the location
717 * Any other value will be considered a failure.
719 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
721 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
723 * ftrace_modify_call - convert from one addr to another (no nop)
724 * @rec: the call site record (e.g. mcount/fentry)
725 * @old_addr: the address expected to be currently called to
726 * @addr: the address to change to
728 * This is a very sensitive operation and great care needs
729 * to be taken by the arch. The operation should carefully
730 * read the location, check to see if what is read is indeed
731 * what we expect it to be, and then on success of the compare,
732 * it should write to the location.
734 * The code segment at @rec->ip should be a caller to @old_addr
738 * -EFAULT on error reading the location
739 * -EINVAL on a failed compare of the contents
740 * -EPERM on error writing to the location
741 * Any other value will be considered a failure.
743 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
746 /* Should never be called */
747 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
754 /* May be defined in arch */
755 extern int ftrace_arch_read_dyn_info(char *buf, int size);
757 extern int skip_trace(unsigned long ip);
758 extern void ftrace_module_init(struct module *mod);
759 extern void ftrace_module_enable(struct module *mod);
760 extern void ftrace_release_mod(struct module *mod);
762 extern void ftrace_disable_daemon(void);
763 extern void ftrace_enable_daemon(void);
764 #else /* CONFIG_DYNAMIC_FTRACE */
765 static inline int skip_trace(unsigned long ip) { return 0; }
766 static inline void ftrace_disable_daemon(void) { }
767 static inline void ftrace_enable_daemon(void) { }
768 static inline void ftrace_module_init(struct module *mod) { }
769 static inline void ftrace_module_enable(struct module *mod) { }
770 static inline void ftrace_release_mod(struct module *mod) { }
771 static inline int ftrace_text_reserved(const void *start, const void *end)
775 static inline unsigned long ftrace_location(unsigned long ip)
781 * Again users of functions that have ftrace_ops may not
782 * have them defined when ftrace is not enabled, but these
783 * functions may still be called. Use a macro instead of inline.
785 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
786 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
787 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
788 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
789 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
790 #define ftrace_free_filter(ops) do { } while (0)
791 #define ftrace_ops_set_global_filter(ops) do { } while (0)
793 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
794 size_t cnt, loff_t *ppos) { return -ENODEV; }
795 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
796 size_t cnt, loff_t *ppos) { return -ENODEV; }
798 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
800 static inline bool is_ftrace_trampoline(unsigned long addr)
804 #endif /* CONFIG_DYNAMIC_FTRACE */
806 /* totally disable ftrace - can not re-enable after this */
807 void ftrace_kill(void);
809 static inline void tracer_disable(void)
811 #ifdef CONFIG_FUNCTION_TRACER
817 * Ftrace disable/restore without lock. Some synchronization mechanism
818 * must be used to prevent ftrace_enabled to be changed between
821 static inline int __ftrace_enabled_save(void)
823 #ifdef CONFIG_FUNCTION_TRACER
824 int saved_ftrace_enabled = ftrace_enabled;
826 return saved_ftrace_enabled;
832 static inline void __ftrace_enabled_restore(int enabled)
834 #ifdef CONFIG_FUNCTION_TRACER
835 ftrace_enabled = enabled;
839 /* All archs should have this, but we define it for consistency */
840 #ifndef ftrace_return_address0
841 # define ftrace_return_address0 __builtin_return_address(0)
844 /* Archs may use other ways for ADDR1 and beyond */
845 #ifndef ftrace_return_address
846 # ifdef CONFIG_FRAME_POINTER
847 # define ftrace_return_address(n) __builtin_return_address(n)
849 # define ftrace_return_address(n) 0UL
853 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
854 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
855 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
856 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
857 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
858 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
859 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
861 static inline unsigned long get_lock_parent_ip(void)
863 unsigned long addr = CALLER_ADDR0;
865 if (!in_lock_functions(addr))
868 if (!in_lock_functions(addr))
873 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
874 extern void trace_preempt_on(unsigned long a0, unsigned long a1);
875 extern void trace_preempt_off(unsigned long a0, unsigned long a1);
878 * Use defines instead of static inlines because some arches will make code out
879 * of the CALLER_ADDR, when we really want these to be a real nop.
881 # define trace_preempt_on(a0, a1) do { } while (0)
882 # define trace_preempt_off(a0, a1) do { } while (0)
885 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
886 extern void ftrace_init(void);
887 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
888 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries"
890 #define FTRACE_CALLSITE_SECTION "__mcount_loc"
893 static inline void ftrace_init(void) { }
897 * Structure that defines an entry function trace.
898 * It's already packed but the attribute "packed" is needed
899 * to remove extra padding at the end.
901 struct ftrace_graph_ent {
902 unsigned long func; /* Current function */
907 * Structure that defines a return function trace.
908 * It's already packed but the attribute "packed" is needed
909 * to remove extra padding at the end.
911 struct ftrace_graph_ret {
912 unsigned long func; /* Current function */
914 /* Number of functions that overran the depth limit for current task */
915 unsigned int overrun;
916 unsigned long long calltime;
917 unsigned long long rettime;
920 /* Type of the callback handlers for tracing function graph*/
921 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
922 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
924 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
926 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
929 trace_func_graph_ent_t entryfunc;
930 trace_func_graph_ret_t retfunc;
934 * Stack of return addresses for functions
936 * Used in struct thread_info
938 struct ftrace_ret_stack {
941 unsigned long long calltime;
942 #ifdef CONFIG_FUNCTION_PROFILER
943 unsigned long long subtime;
945 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
948 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
954 * Primary handler of a function return.
955 * It relays on ftrace_return_to_handler.
956 * Defined in entry_32/64.S
958 extern void return_to_handler(void);
961 function_graph_enter(unsigned long ret, unsigned long func,
962 unsigned long frame_pointer, unsigned long *retp);
964 struct ftrace_ret_stack *
965 ftrace_graph_get_ret_stack(struct task_struct *task, int idx);
967 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
968 unsigned long ret, unsigned long *retp);
971 * Sometimes we don't want to trace a function with the function
972 * graph tracer but we want them to keep traced by the usual function
973 * tracer if the function graph tracer is not configured.
975 #define __notrace_funcgraph notrace
977 #define FTRACE_RETFUNC_DEPTH 50
978 #define FTRACE_RETSTACK_ALLOC_SIZE 32
980 extern int register_ftrace_graph(struct fgraph_ops *ops);
981 extern void unregister_ftrace_graph(struct fgraph_ops *ops);
983 extern bool ftrace_graph_is_dead(void);
984 extern void ftrace_graph_stop(void);
986 /* The current handlers in use */
987 extern trace_func_graph_ret_t ftrace_graph_return;
988 extern trace_func_graph_ent_t ftrace_graph_entry;
990 extern void ftrace_graph_init_task(struct task_struct *t);
991 extern void ftrace_graph_exit_task(struct task_struct *t);
992 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
994 static inline void pause_graph_tracing(void)
996 atomic_inc(¤t->tracing_graph_pause);
999 static inline void unpause_graph_tracing(void)
1001 atomic_dec(¤t->tracing_graph_pause);
1003 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
1005 #define __notrace_funcgraph
1007 static inline void ftrace_graph_init_task(struct task_struct *t) { }
1008 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
1009 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
1011 /* Define as macros as fgraph_ops may not be defined */
1012 #define register_ftrace_graph(ops) ({ -1; })
1013 #define unregister_ftrace_graph(ops) do { } while (0)
1015 static inline unsigned long
1016 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
1017 unsigned long *retp)
1022 static inline void pause_graph_tracing(void) { }
1023 static inline void unpause_graph_tracing(void) { }
1024 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1026 #ifdef CONFIG_TRACING
1028 /* flags for current->trace */
1030 TSK_TRACE_FL_TRACE_BIT = 0,
1031 TSK_TRACE_FL_GRAPH_BIT = 1,
1034 TSK_TRACE_FL_TRACE = 1 << TSK_TRACE_FL_TRACE_BIT,
1035 TSK_TRACE_FL_GRAPH = 1 << TSK_TRACE_FL_GRAPH_BIT,
1038 static inline void set_tsk_trace_trace(struct task_struct *tsk)
1040 set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
1043 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
1045 clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
1048 static inline int test_tsk_trace_trace(struct task_struct *tsk)
1050 return tsk->trace & TSK_TRACE_FL_TRACE;
1053 static inline void set_tsk_trace_graph(struct task_struct *tsk)
1055 set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
1058 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
1060 clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
1063 static inline int test_tsk_trace_graph(struct task_struct *tsk)
1065 return tsk->trace & TSK_TRACE_FL_GRAPH;
1068 enum ftrace_dump_mode;
1070 extern enum ftrace_dump_mode ftrace_dump_on_oops;
1071 extern int tracepoint_printk;
1073 extern void disable_trace_on_warning(void);
1074 extern int __disable_trace_on_warning;
1076 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
1077 void *buffer, size_t *lenp, loff_t *ppos);
1079 #else /* CONFIG_TRACING */
1080 static inline void disable_trace_on_warning(void) { }
1081 #endif /* CONFIG_TRACING */
1083 #ifdef CONFIG_FTRACE_SYSCALLS
1085 unsigned long arch_syscall_addr(int nr);
1087 #endif /* CONFIG_FTRACE_SYSCALLS */
1089 #endif /* _LINUX_FTRACE_H */