xref: /linux-6.15/kernel/trace/trace.h (revision f60d24d2)
1 #ifndef _LINUX_KERNEL_TRACE_H
2 #define _LINUX_KERNEL_TRACE_H
3 
4 #include <linux/fs.h>
5 #include <asm/atomic.h>
6 #include <linux/sched.h>
7 #include <linux/clocksource.h>
8 #include <linux/ring_buffer.h>
9 #include <linux/mmiotrace.h>
10 #include <linux/tracepoint.h>
11 #include <linux/ftrace.h>
12 #include <trace/boot.h>
13 #include <linux/kmemtrace.h>
14 #include <linux/hw_breakpoint.h>
15 
16 #include <linux/trace_seq.h>
17 #include <linux/ftrace_event.h>
18 
19 enum trace_type {
20 	__TRACE_FIRST_TYPE = 0,
21 
22 	TRACE_FN,
23 	TRACE_CTX,
24 	TRACE_WAKE,
25 	TRACE_STACK,
26 	TRACE_PRINT,
27 	TRACE_BPRINT,
28 	TRACE_SPECIAL,
29 	TRACE_MMIO_RW,
30 	TRACE_MMIO_MAP,
31 	TRACE_BRANCH,
32 	TRACE_BOOT_CALL,
33 	TRACE_BOOT_RET,
34 	TRACE_GRAPH_RET,
35 	TRACE_GRAPH_ENT,
36 	TRACE_USER_STACK,
37 	TRACE_HW_BRANCHES,
38 	TRACE_KMEM_ALLOC,
39 	TRACE_KMEM_FREE,
40 	TRACE_BLK,
41 	TRACE_KSYM,
42 
43 	__TRACE_LAST_TYPE,
44 };
45 
46 enum kmemtrace_type_id {
47 	KMEMTRACE_TYPE_KMALLOC = 0,	/* kmalloc() or kfree(). */
48 	KMEMTRACE_TYPE_CACHE,		/* kmem_cache_*(). */
49 	KMEMTRACE_TYPE_PAGES,		/* __get_free_pages() and friends. */
50 };
51 
52 extern struct tracer boot_tracer;
53 
54 #undef __field
55 #define __field(type, item)		type	item;
56 
57 #undef __field_struct
58 #define __field_struct(type, item)	__field(type, item)
59 
60 #undef __field_desc
61 #define __field_desc(type, container, item)
62 
63 #undef __array
64 #define __array(type, item, size)	type	item[size];
65 
66 #undef __array_desc
67 #define __array_desc(type, container, item, size)
68 
69 #undef __dynamic_array
70 #define __dynamic_array(type, item)	type	item[];
71 
72 #undef F_STRUCT
73 #define F_STRUCT(args...)		args
74 
75 #undef FTRACE_ENTRY
76 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)	\
77 	struct struct_name {					\
78 		struct trace_entry	ent;			\
79 		tstruct						\
80 	}
81 
82 #undef TP_ARGS
83 #define TP_ARGS(args...)	args
84 
85 #undef FTRACE_ENTRY_DUP
86 #define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)
87 
88 #include "trace_entries.h"
89 
90 /*
91  * syscalls are special, and need special handling, this is why
92  * they are not included in trace_entries.h
93  */
94 struct syscall_trace_enter {
95 	struct trace_entry	ent;
96 	int			nr;
97 	unsigned long		args[];
98 };
99 
100 struct syscall_trace_exit {
101 	struct trace_entry	ent;
102 	int			nr;
103 	unsigned long		ret;
104 };
105 
106 /*
107  * trace_flag_type is an enumeration that holds different
108  * states when a trace occurs. These are:
109  *  IRQS_OFF		- interrupts were disabled
110  *  IRQS_NOSUPPORT	- arch does not support irqs_disabled_flags
111  *  NEED_RESCHED	- reschedule is requested
112  *  HARDIRQ		- inside an interrupt handler
113  *  SOFTIRQ		- inside a softirq handler
114  */
115 enum trace_flag_type {
116 	TRACE_FLAG_IRQS_OFF		= 0x01,
117 	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
118 	TRACE_FLAG_NEED_RESCHED		= 0x04,
119 	TRACE_FLAG_HARDIRQ		= 0x08,
120 	TRACE_FLAG_SOFTIRQ		= 0x10,
121 };
122 
123 #define TRACE_BUF_SIZE		1024
124 
125 /*
126  * The CPU trace array - it consists of thousands of trace entries
127  * plus some other descriptor data: (for example which task started
128  * the trace, etc.)
129  */
130 struct trace_array_cpu {
131 	atomic_t		disabled;
132 	void			*buffer_page;	/* ring buffer spare */
133 
134 	unsigned long		saved_latency;
135 	unsigned long		critical_start;
136 	unsigned long		critical_end;
137 	unsigned long		critical_sequence;
138 	unsigned long		nice;
139 	unsigned long		policy;
140 	unsigned long		rt_priority;
141 	unsigned long		skipped_entries;
142 	cycle_t			preempt_timestamp;
143 	pid_t			pid;
144 	uid_t			uid;
145 	char			comm[TASK_COMM_LEN];
146 };
147 
148 /*
149  * The trace array - an array of per-CPU trace arrays. This is the
150  * highest level data structure that individual tracers deal with.
151  * They have on/off state as well:
152  */
153 struct trace_array {
154 	struct ring_buffer	*buffer;
155 	unsigned long		entries;
156 	int			cpu;
157 	cycle_t			time_start;
158 	struct task_struct	*waiter;
159 	struct trace_array_cpu	*data[NR_CPUS];
160 };
161 
162 #define FTRACE_CMP_TYPE(var, type) \
163 	__builtin_types_compatible_p(typeof(var), type *)
164 
165 #undef IF_ASSIGN
166 #define IF_ASSIGN(var, entry, etype, id)		\
167 	if (FTRACE_CMP_TYPE(var, etype)) {		\
168 		var = (typeof(var))(entry);		\
169 		WARN_ON(id && (entry)->type != id);	\
170 		break;					\
171 	}
172 
173 /* Will cause compile errors if type is not found. */
174 extern void __ftrace_bad_type(void);
175 
176 /*
177  * The trace_assign_type is a verifier that the entry type is
178  * the same as the type being assigned. To add new types simply
179  * add a line with the following format:
180  *
181  * IF_ASSIGN(var, ent, type, id);
182  *
183  *  Where "type" is the trace type that includes the trace_entry
184  *  as the "ent" item. And "id" is the trace identifier that is
185  *  used in the trace_type enum.
186  *
187  *  If the type can have more than one id, then use zero.
188  */
189 #define trace_assign_type(var, ent)					\
190 	do {								\
191 		IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);	\
192 		IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);	\
193 		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
194 		IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
195 		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
196 		IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT);	\
197 		IF_ASSIGN(var, ent, struct special_entry, 0);		\
198 		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
199 			  TRACE_MMIO_RW);				\
200 		IF_ASSIGN(var, ent, struct trace_mmiotrace_map,		\
201 			  TRACE_MMIO_MAP);				\
202 		IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
203 		IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
204 		IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
205 		IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,	\
206 			  TRACE_GRAPH_ENT);		\
207 		IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,	\
208 			  TRACE_GRAPH_RET);		\
209 		IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
210 		IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,	\
211 			  TRACE_KMEM_ALLOC);	\
212 		IF_ASSIGN(var, ent, struct kmemtrace_free_entry,	\
213 			  TRACE_KMEM_FREE);	\
214 		IF_ASSIGN(var, ent, struct ksym_trace_entry, TRACE_KSYM);\
215 		__ftrace_bad_type();					\
216 	} while (0)
217 
218 /*
219  * An option specific to a tracer. This is a boolean value.
220  * The bit is the bit index that sets its value on the
221  * flags value in struct tracer_flags.
222  */
223 struct tracer_opt {
224 	const char	*name; /* Will appear on the trace_options file */
225 	u32		bit; /* Mask assigned in val field in tracer_flags */
226 };
227 
228 /*
229  * The set of specific options for a tracer. Your tracer
230  * have to set the initial value of the flags val.
231  */
232 struct tracer_flags {
233 	u32			val;
234 	struct tracer_opt	*opts;
235 };
236 
237 /* Makes more easy to define a tracer opt */
238 #define TRACER_OPT(s, b)	.name = #s, .bit = b
239 
240 
241 /**
242  * struct tracer - a specific tracer and its callbacks to interact with debugfs
243  * @name: the name chosen to select it on the available_tracers file
244  * @init: called when one switches to this tracer (echo name > current_tracer)
245  * @reset: called when one switches to another tracer
246  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
247  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
248  * @open: called when the trace file is opened
249  * @pipe_open: called when the trace_pipe file is opened
250  * @wait_pipe: override how the user waits for traces on trace_pipe
251  * @close: called when the trace file is released
252  * @read: override the default read callback on trace_pipe
253  * @splice_read: override the default splice_read callback on trace_pipe
254  * @selftest: selftest to run on boot (see trace_selftest.c)
255  * @print_headers: override the first lines that describe your columns
256  * @print_line: callback that prints a trace
257  * @set_flag: signals one of your private flags changed (trace_options file)
258  * @flags: your private flags
259  */
260 struct tracer {
261 	const char		*name;
262 	int			(*init)(struct trace_array *tr);
263 	void			(*reset)(struct trace_array *tr);
264 	void			(*start)(struct trace_array *tr);
265 	void			(*stop)(struct trace_array *tr);
266 	void			(*open)(struct trace_iterator *iter);
267 	void			(*pipe_open)(struct trace_iterator *iter);
268 	void			(*wait_pipe)(struct trace_iterator *iter);
269 	void			(*close)(struct trace_iterator *iter);
270 	ssize_t			(*read)(struct trace_iterator *iter,
271 					struct file *filp, char __user *ubuf,
272 					size_t cnt, loff_t *ppos);
273 	ssize_t			(*splice_read)(struct trace_iterator *iter,
274 					       struct file *filp,
275 					       loff_t *ppos,
276 					       struct pipe_inode_info *pipe,
277 					       size_t len,
278 					       unsigned int flags);
279 #ifdef CONFIG_FTRACE_STARTUP_TEST
280 	int			(*selftest)(struct tracer *trace,
281 					    struct trace_array *tr);
282 #endif
283 	void			(*print_header)(struct seq_file *m);
284 	enum print_line_t	(*print_line)(struct trace_iterator *iter);
285 	/* If you handled the flag setting, return 0 */
286 	int			(*set_flag)(u32 old_flags, u32 bit, int set);
287 	struct tracer		*next;
288 	int			print_max;
289 	struct tracer_flags	*flags;
290 };
291 
292 
293 #define TRACE_PIPE_ALL_CPU	-1
294 
295 int tracer_init(struct tracer *t, struct trace_array *tr);
296 int tracing_is_enabled(void);
297 void trace_wake_up(void);
298 void tracing_reset(struct trace_array *tr, int cpu);
299 void tracing_reset_online_cpus(struct trace_array *tr);
300 void tracing_reset_current(int cpu);
301 void tracing_reset_current_online_cpus(void);
302 int tracing_open_generic(struct inode *inode, struct file *filp);
303 struct dentry *trace_create_file(const char *name,
304 				 mode_t mode,
305 				 struct dentry *parent,
306 				 void *data,
307 				 const struct file_operations *fops);
308 
309 struct dentry *tracing_init_dentry(void);
310 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
311 
312 struct ring_buffer_event;
313 
314 struct ring_buffer_event *
315 trace_buffer_lock_reserve(struct ring_buffer *buffer,
316 			  int type,
317 			  unsigned long len,
318 			  unsigned long flags,
319 			  int pc);
320 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
321 				struct ring_buffer_event *event,
322 				unsigned long flags, int pc);
323 
324 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
325 						struct trace_array_cpu *data);
326 
327 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
328 					  int *ent_cpu, u64 *ent_ts);
329 
330 void default_wait_pipe(struct trace_iterator *iter);
331 void poll_wait_pipe(struct trace_iterator *iter);
332 
333 void ftrace(struct trace_array *tr,
334 			    struct trace_array_cpu *data,
335 			    unsigned long ip,
336 			    unsigned long parent_ip,
337 			    unsigned long flags, int pc);
338 void tracing_sched_switch_trace(struct trace_array *tr,
339 				struct task_struct *prev,
340 				struct task_struct *next,
341 				unsigned long flags, int pc);
342 
343 void tracing_sched_wakeup_trace(struct trace_array *tr,
344 				struct task_struct *wakee,
345 				struct task_struct *cur,
346 				unsigned long flags, int pc);
347 void trace_special(struct trace_array *tr,
348 		   struct trace_array_cpu *data,
349 		   unsigned long arg1,
350 		   unsigned long arg2,
351 		   unsigned long arg3, int pc);
352 void trace_function(struct trace_array *tr,
353 		    unsigned long ip,
354 		    unsigned long parent_ip,
355 		    unsigned long flags, int pc);
356 
357 void trace_graph_return(struct ftrace_graph_ret *trace);
358 int trace_graph_entry(struct ftrace_graph_ent *trace);
359 void set_graph_array(struct trace_array *tr);
360 
361 void tracing_start_cmdline_record(void);
362 void tracing_stop_cmdline_record(void);
363 void tracing_sched_switch_assign_trace(struct trace_array *tr);
364 void tracing_stop_sched_switch_record(void);
365 void tracing_start_sched_switch_record(void);
366 int register_tracer(struct tracer *type);
367 void unregister_tracer(struct tracer *type);
368 int is_tracing_stopped(void);
369 
370 extern int process_new_ksym_entry(char *ksymname, int op, unsigned long addr);
371 
372 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
373 
374 #ifdef CONFIG_TRACER_MAX_TRACE
375 extern unsigned long tracing_max_latency;
376 extern unsigned long tracing_thresh;
377 
378 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
379 void update_max_tr_single(struct trace_array *tr,
380 			  struct task_struct *tsk, int cpu);
381 #endif /* CONFIG_TRACER_MAX_TRACE */
382 
383 #ifdef CONFIG_STACKTRACE
384 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
385 			int skip, int pc);
386 
387 void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
388 			    int pc);
389 
390 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
391 		   int pc);
392 #else
393 static inline void ftrace_trace_stack(struct trace_array *tr,
394 				      unsigned long flags, int skip, int pc)
395 {
396 }
397 
398 static inline void ftrace_trace_userstack(struct trace_array *tr,
399 					  unsigned long flags, int pc)
400 {
401 }
402 
403 static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
404 				 int skip, int pc)
405 {
406 }
407 #endif /* CONFIG_STACKTRACE */
408 
409 extern cycle_t ftrace_now(int cpu);
410 
411 extern void trace_find_cmdline(int pid, char comm[]);
412 
413 #ifdef CONFIG_DYNAMIC_FTRACE
414 extern unsigned long ftrace_update_tot_cnt;
415 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
416 extern int DYN_FTRACE_TEST_NAME(void);
417 #endif
418 
419 extern int ring_buffer_expanded;
420 extern bool tracing_selftest_disabled;
421 DECLARE_PER_CPU(local_t, ftrace_cpu_disabled);
422 
423 #ifdef CONFIG_FTRACE_STARTUP_TEST
424 extern int trace_selftest_startup_function(struct tracer *trace,
425 					   struct trace_array *tr);
426 extern int trace_selftest_startup_function_graph(struct tracer *trace,
427 						 struct trace_array *tr);
428 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
429 					  struct trace_array *tr);
430 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
431 					     struct trace_array *tr);
432 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
433 						 struct trace_array *tr);
434 extern int trace_selftest_startup_wakeup(struct tracer *trace,
435 					 struct trace_array *tr);
436 extern int trace_selftest_startup_nop(struct tracer *trace,
437 					 struct trace_array *tr);
438 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
439 					       struct trace_array *tr);
440 extern int trace_selftest_startup_sysprof(struct tracer *trace,
441 					       struct trace_array *tr);
442 extern int trace_selftest_startup_branch(struct tracer *trace,
443 					 struct trace_array *tr);
444 extern int trace_selftest_startup_hw_branches(struct tracer *trace,
445 					      struct trace_array *tr);
446 extern int trace_selftest_startup_ksym(struct tracer *trace,
447 					 struct trace_array *tr);
448 #endif /* CONFIG_FTRACE_STARTUP_TEST */
449 
450 extern void *head_page(struct trace_array_cpu *data);
451 extern unsigned long long ns2usecs(cycle_t nsec);
452 extern int
453 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
454 extern int
455 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
456 extern int
457 trace_array_vprintk(struct trace_array *tr,
458 		    unsigned long ip, const char *fmt, va_list args);
459 int trace_array_printk(struct trace_array *tr,
460 		       unsigned long ip, const char *fmt, ...);
461 
462 extern unsigned long trace_flags;
463 
464 extern int trace_clock_id;
465 
466 /* Standard output formatting function used for function return traces */
467 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
468 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
469 extern enum print_line_t
470 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
471 
472 #ifdef CONFIG_DYNAMIC_FTRACE
473 /* TODO: make this variable */
474 #define FTRACE_GRAPH_MAX_FUNCS		32
475 extern int ftrace_graph_count;
476 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
477 
478 static inline int ftrace_graph_addr(unsigned long addr)
479 {
480 	int i;
481 
482 	if (!ftrace_graph_count || test_tsk_trace_graph(current))
483 		return 1;
484 
485 	for (i = 0; i < ftrace_graph_count; i++) {
486 		if (addr == ftrace_graph_funcs[i])
487 			return 1;
488 	}
489 
490 	return 0;
491 }
492 #else
493 static inline int ftrace_graph_addr(unsigned long addr)
494 {
495 	return 1;
496 }
497 #endif /* CONFIG_DYNAMIC_FTRACE */
498 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
499 static inline enum print_line_t
500 print_graph_function(struct trace_iterator *iter)
501 {
502 	return TRACE_TYPE_UNHANDLED;
503 }
504 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
505 
506 extern struct list_head ftrace_pids;
507 
508 #ifdef CONFIG_FUNCTION_TRACER
509 static inline int ftrace_trace_task(struct task_struct *task)
510 {
511 	if (list_empty(&ftrace_pids))
512 		return 1;
513 
514 	return test_tsk_trace_trace(task);
515 }
516 #else
517 static inline int ftrace_trace_task(struct task_struct *task)
518 {
519 	return 1;
520 }
521 #endif
522 
523 /*
524  * struct trace_parser - servers for reading the user input separated by spaces
525  * @cont: set if the input is not complete - no final space char was found
526  * @buffer: holds the parsed user input
527  * @idx: user input lenght
528  * @size: buffer size
529  */
530 struct trace_parser {
531 	bool		cont;
532 	char		*buffer;
533 	unsigned	idx;
534 	unsigned	size;
535 };
536 
537 static inline bool trace_parser_loaded(struct trace_parser *parser)
538 {
539 	return (parser->idx != 0);
540 }
541 
542 static inline bool trace_parser_cont(struct trace_parser *parser)
543 {
544 	return parser->cont;
545 }
546 
547 static inline void trace_parser_clear(struct trace_parser *parser)
548 {
549 	parser->cont = false;
550 	parser->idx = 0;
551 }
552 
553 extern int trace_parser_get_init(struct trace_parser *parser, int size);
554 extern void trace_parser_put(struct trace_parser *parser);
555 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
556 	size_t cnt, loff_t *ppos);
557 
558 /*
559  * trace_iterator_flags is an enumeration that defines bit
560  * positions into trace_flags that controls the output.
561  *
562  * NOTE: These bits must match the trace_options array in
563  *       trace.c.
564  */
565 enum trace_iterator_flags {
566 	TRACE_ITER_PRINT_PARENT		= 0x01,
567 	TRACE_ITER_SYM_OFFSET		= 0x02,
568 	TRACE_ITER_SYM_ADDR		= 0x04,
569 	TRACE_ITER_VERBOSE		= 0x08,
570 	TRACE_ITER_RAW			= 0x10,
571 	TRACE_ITER_HEX			= 0x20,
572 	TRACE_ITER_BIN			= 0x40,
573 	TRACE_ITER_BLOCK		= 0x80,
574 	TRACE_ITER_STACKTRACE		= 0x100,
575 	TRACE_ITER_SCHED_TREE		= 0x200,
576 	TRACE_ITER_PRINTK		= 0x400,
577 	TRACE_ITER_PREEMPTONLY		= 0x800,
578 	TRACE_ITER_BRANCH		= 0x1000,
579 	TRACE_ITER_ANNOTATE		= 0x2000,
580 	TRACE_ITER_USERSTACKTRACE       = 0x4000,
581 	TRACE_ITER_SYM_USEROBJ          = 0x8000,
582 	TRACE_ITER_PRINTK_MSGONLY	= 0x10000,
583 	TRACE_ITER_CONTEXT_INFO		= 0x20000, /* Print pid/cpu/time */
584 	TRACE_ITER_LATENCY_FMT		= 0x40000,
585 	TRACE_ITER_SLEEP_TIME		= 0x80000,
586 	TRACE_ITER_GRAPH_TIME		= 0x100000,
587 };
588 
589 /*
590  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
591  * control the output of kernel symbols.
592  */
593 #define TRACE_ITER_SYM_MASK \
594 	(TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
595 
596 extern struct tracer nop_trace;
597 
598 /**
599  * ftrace_preempt_disable - disable preemption scheduler safe
600  *
601  * When tracing can happen inside the scheduler, there exists
602  * cases that the tracing might happen before the need_resched
603  * flag is checked. If this happens and the tracer calls
604  * preempt_enable (after a disable), a schedule might take place
605  * causing an infinite recursion.
606  *
607  * To prevent this, we read the need_resched flag before
608  * disabling preemption. When we want to enable preemption we
609  * check the flag, if it is set, then we call preempt_enable_no_resched.
610  * Otherwise, we call preempt_enable.
611  *
612  * The rational for doing the above is that if need_resched is set
613  * and we have yet to reschedule, we are either in an atomic location
614  * (where we do not need to check for scheduling) or we are inside
615  * the scheduler and do not want to resched.
616  */
617 static inline int ftrace_preempt_disable(void)
618 {
619 	int resched;
620 
621 	resched = need_resched();
622 	preempt_disable_notrace();
623 
624 	return resched;
625 }
626 
627 /**
628  * ftrace_preempt_enable - enable preemption scheduler safe
629  * @resched: the return value from ftrace_preempt_disable
630  *
631  * This is a scheduler safe way to enable preemption and not miss
632  * any preemption checks. The disabled saved the state of preemption.
633  * If resched is set, then we are either inside an atomic or
634  * are inside the scheduler (we would have already scheduled
635  * otherwise). In this case, we do not want to call normal
636  * preempt_enable, but preempt_enable_no_resched instead.
637  */
638 static inline void ftrace_preempt_enable(int resched)
639 {
640 	if (resched)
641 		preempt_enable_no_resched_notrace();
642 	else
643 		preempt_enable_notrace();
644 }
645 
646 #ifdef CONFIG_BRANCH_TRACER
647 extern int enable_branch_tracing(struct trace_array *tr);
648 extern void disable_branch_tracing(void);
649 static inline int trace_branch_enable(struct trace_array *tr)
650 {
651 	if (trace_flags & TRACE_ITER_BRANCH)
652 		return enable_branch_tracing(tr);
653 	return 0;
654 }
655 static inline void trace_branch_disable(void)
656 {
657 	/* due to races, always disable */
658 	disable_branch_tracing();
659 }
660 #else
661 static inline int trace_branch_enable(struct trace_array *tr)
662 {
663 	return 0;
664 }
665 static inline void trace_branch_disable(void)
666 {
667 }
668 #endif /* CONFIG_BRANCH_TRACER */
669 
670 /* set ring buffers to default size if not already done so */
671 int tracing_update_buffers(void);
672 
673 /* trace event type bit fields, not numeric */
674 enum {
675 	TRACE_EVENT_TYPE_PRINTF		= 1,
676 	TRACE_EVENT_TYPE_RAW		= 2,
677 };
678 
679 struct ftrace_event_field {
680 	struct list_head	link;
681 	char			*name;
682 	char			*type;
683 	int			filter_type;
684 	int			offset;
685 	int			size;
686 	int			is_signed;
687 };
688 
689 struct event_filter {
690 	int			n_preds;
691 	struct filter_pred	**preds;
692 	char			*filter_string;
693 };
694 
695 struct event_subsystem {
696 	struct list_head	list;
697 	const char		*name;
698 	struct dentry		*entry;
699 	struct event_filter	*filter;
700 	int			nr_events;
701 };
702 
703 struct filter_pred;
704 struct regex;
705 
706 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
707 				 int val1, int val2);
708 
709 typedef int (*regex_match_func)(char *str, struct regex *r, int len);
710 
711 enum regex_type {
712 	MATCH_FULL = 0,
713 	MATCH_FRONT_ONLY,
714 	MATCH_MIDDLE_ONLY,
715 	MATCH_END_ONLY,
716 };
717 
718 struct regex {
719 	char			pattern[MAX_FILTER_STR_VAL];
720 	int			len;
721 	int			field_len;
722 	regex_match_func	match;
723 };
724 
725 struct filter_pred {
726 	filter_pred_fn_t 	fn;
727 	u64 			val;
728 	struct regex		regex;
729 	char 			*field_name;
730 	int 			offset;
731 	int 			not;
732 	int 			op;
733 	int 			pop_n;
734 };
735 
736 extern enum regex_type
737 filter_parse_regex(char *buff, int len, char **search, int *not);
738 extern void print_event_filter(struct ftrace_event_call *call,
739 			       struct trace_seq *s);
740 extern int apply_event_filter(struct ftrace_event_call *call,
741 			      char *filter_string);
742 extern int apply_subsystem_event_filter(struct event_subsystem *system,
743 					char *filter_string);
744 extern void print_subsystem_event_filter(struct event_subsystem *system,
745 					 struct trace_seq *s);
746 extern int filter_assign_type(const char *type);
747 
748 static inline int
749 filter_check_discard(struct ftrace_event_call *call, void *rec,
750 		     struct ring_buffer *buffer,
751 		     struct ring_buffer_event *event)
752 {
753 	if (unlikely(call->filter_active) &&
754 	    !filter_match_preds(call->filter, rec)) {
755 		ring_buffer_discard_commit(buffer, event);
756 		return 1;
757 	}
758 
759 	return 0;
760 }
761 
762 extern struct mutex event_mutex;
763 extern struct list_head ftrace_events;
764 
765 extern const char *__start___trace_bprintk_fmt[];
766 extern const char *__stop___trace_bprintk_fmt[];
767 
768 #undef FTRACE_ENTRY
769 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print)		\
770 	extern struct ftrace_event_call event_##call;
771 #undef FTRACE_ENTRY_DUP
772 #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)		\
773 	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
774 #include "trace_entries.h"
775 
776 #endif /* _LINUX_KERNEL_TRACE_H */
777