xref: /linux-6.15/include/linux/trace_events.h (revision bb7e5ce7)
1 
2 #ifndef _LINUX_TRACE_EVENT_H
3 #define _LINUX_TRACE_EVENT_H
4 
5 #include <linux/ring_buffer.h>
6 #include <linux/trace_seq.h>
7 #include <linux/percpu.h>
8 #include <linux/hardirq.h>
9 #include <linux/perf_event.h>
10 #include <linux/tracepoint.h>
11 
12 struct trace_array;
13 struct trace_buffer;
14 struct tracer;
15 struct dentry;
16 struct bpf_prog;
17 
18 const char *trace_print_flags_seq(struct trace_seq *p, const char *delim,
19 				  unsigned long flags,
20 				  const struct trace_print_flags *flag_array);
21 
22 const char *trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
23 				    const struct trace_print_flags *symbol_array);
24 
25 #if BITS_PER_LONG == 32
26 const char *trace_print_flags_seq_u64(struct trace_seq *p, const char *delim,
27 		      unsigned long long flags,
28 		      const struct trace_print_flags_u64 *flag_array);
29 
30 const char *trace_print_symbols_seq_u64(struct trace_seq *p,
31 					unsigned long long val,
32 					const struct trace_print_flags_u64
33 								 *symbol_array);
34 #endif
35 
36 const char *trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
37 				    unsigned int bitmask_size);
38 
39 const char *trace_print_hex_seq(struct trace_seq *p,
40 				const unsigned char *buf, int len,
41 				bool concatenate);
42 
43 const char *trace_print_array_seq(struct trace_seq *p,
44 				   const void *buf, int count,
45 				   size_t el_size);
46 
47 struct trace_iterator;
48 struct trace_event;
49 
50 int trace_raw_output_prep(struct trace_iterator *iter,
51 			  struct trace_event *event);
52 
53 /*
54  * The trace entry - the most basic unit of tracing. This is what
55  * is printed in the end as a single line in the trace output, such as:
56  *
57  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
58  */
59 struct trace_entry {
60 	unsigned short		type;
61 	unsigned char		flags;
62 	unsigned char		preempt_count;
63 	int			pid;
64 };
65 
66 #define TRACE_EVENT_TYPE_MAX						\
67 	((1 << (sizeof(((struct trace_entry *)0)->type) * 8)) - 1)
68 
69 /*
70  * Trace iterator - used by printout routines who present trace
71  * results to users and which routines might sleep, etc:
72  */
73 struct trace_iterator {
74 	struct trace_array	*tr;
75 	struct tracer		*trace;
76 	struct trace_buffer	*trace_buffer;
77 	void			*private;
78 	int			cpu_file;
79 	struct mutex		mutex;
80 	struct ring_buffer_iter	**buffer_iter;
81 	unsigned long		iter_flags;
82 
83 	/* trace_seq for __print_flags() and __print_symbolic() etc. */
84 	struct trace_seq	tmp_seq;
85 
86 	cpumask_var_t		started;
87 
88 	/* it's true when current open file is snapshot */
89 	bool			snapshot;
90 
91 	/* The below is zeroed out in pipe_read */
92 	struct trace_seq	seq;
93 	struct trace_entry	*ent;
94 	unsigned long		lost_events;
95 	int			leftover;
96 	int			ent_size;
97 	int			cpu;
98 	u64			ts;
99 
100 	loff_t			pos;
101 	long			idx;
102 
103 	/* All new field here will be zeroed out in pipe_read */
104 };
105 
106 enum trace_iter_flags {
107 	TRACE_FILE_LAT_FMT	= 1,
108 	TRACE_FILE_ANNOTATE	= 2,
109 	TRACE_FILE_TIME_IN_NS	= 4,
110 };
111 
112 
113 typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
114 				      int flags, struct trace_event *event);
115 
116 struct trace_event_functions {
117 	trace_print_func	trace;
118 	trace_print_func	raw;
119 	trace_print_func	hex;
120 	trace_print_func	binary;
121 };
122 
123 struct trace_event {
124 	struct hlist_node		node;
125 	struct list_head		list;
126 	int				type;
127 	struct trace_event_functions	*funcs;
128 };
129 
130 extern int register_trace_event(struct trace_event *event);
131 extern int unregister_trace_event(struct trace_event *event);
132 
133 /* Return values for print_line callback */
134 enum print_line_t {
135 	TRACE_TYPE_PARTIAL_LINE	= 0,	/* Retry after flushing the seq */
136 	TRACE_TYPE_HANDLED	= 1,
137 	TRACE_TYPE_UNHANDLED	= 2,	/* Relay to other output functions */
138 	TRACE_TYPE_NO_CONSUME	= 3	/* Handled but ask to not consume */
139 };
140 
141 enum print_line_t trace_handle_return(struct trace_seq *s);
142 
143 void tracing_generic_entry_update(struct trace_entry *entry,
144 				  unsigned long flags,
145 				  int pc);
146 struct trace_event_file;
147 
148 struct ring_buffer_event *
149 trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
150 				struct trace_event_file *trace_file,
151 				int type, unsigned long len,
152 				unsigned long flags, int pc);
153 
154 #define TRACE_RECORD_CMDLINE	BIT(0)
155 #define TRACE_RECORD_TGID	BIT(1)
156 
157 void tracing_record_taskinfo(struct task_struct *task, int flags);
158 void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
159 					  struct task_struct *next, int flags);
160 
161 void tracing_record_cmdline(struct task_struct *task);
162 void tracing_record_tgid(struct task_struct *task);
163 
164 int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...);
165 
166 struct event_filter;
167 
168 enum trace_reg {
169 	TRACE_REG_REGISTER,
170 	TRACE_REG_UNREGISTER,
171 #ifdef CONFIG_PERF_EVENTS
172 	TRACE_REG_PERF_REGISTER,
173 	TRACE_REG_PERF_UNREGISTER,
174 	TRACE_REG_PERF_OPEN,
175 	TRACE_REG_PERF_CLOSE,
176 	TRACE_REG_PERF_ADD,
177 	TRACE_REG_PERF_DEL,
178 #endif
179 };
180 
181 struct trace_event_call;
182 
183 struct trace_event_class {
184 	const char		*system;
185 	void			*probe;
186 #ifdef CONFIG_PERF_EVENTS
187 	void			*perf_probe;
188 #endif
189 	int			(*reg)(struct trace_event_call *event,
190 				       enum trace_reg type, void *data);
191 	int			(*define_fields)(struct trace_event_call *);
192 	struct list_head	*(*get_fields)(struct trace_event_call *);
193 	struct list_head	fields;
194 	int			(*raw_init)(struct trace_event_call *);
195 };
196 
197 extern int trace_event_reg(struct trace_event_call *event,
198 			    enum trace_reg type, void *data);
199 
200 struct trace_event_buffer {
201 	struct ring_buffer		*buffer;
202 	struct ring_buffer_event	*event;
203 	struct trace_event_file		*trace_file;
204 	void				*entry;
205 	unsigned long			flags;
206 	int				pc;
207 };
208 
209 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
210 				  struct trace_event_file *trace_file,
211 				  unsigned long len);
212 
213 void trace_event_buffer_commit(struct trace_event_buffer *fbuffer);
214 
215 enum {
216 	TRACE_EVENT_FL_FILTERED_BIT,
217 	TRACE_EVENT_FL_CAP_ANY_BIT,
218 	TRACE_EVENT_FL_NO_SET_FILTER_BIT,
219 	TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
220 	TRACE_EVENT_FL_TRACEPOINT_BIT,
221 	TRACE_EVENT_FL_KPROBE_BIT,
222 	TRACE_EVENT_FL_UPROBE_BIT,
223 };
224 
225 /*
226  * Event flags:
227  *  FILTERED	  - The event has a filter attached
228  *  CAP_ANY	  - Any user can enable for perf
229  *  NO_SET_FILTER - Set when filter has error and is to be ignored
230  *  IGNORE_ENABLE - For trace internal events, do not enable with debugfs file
231  *  TRACEPOINT    - Event is a tracepoint
232  *  KPROBE        - Event is a kprobe
233  *  UPROBE        - Event is a uprobe
234  */
235 enum {
236 	TRACE_EVENT_FL_FILTERED		= (1 << TRACE_EVENT_FL_FILTERED_BIT),
237 	TRACE_EVENT_FL_CAP_ANY		= (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
238 	TRACE_EVENT_FL_NO_SET_FILTER	= (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
239 	TRACE_EVENT_FL_IGNORE_ENABLE	= (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
240 	TRACE_EVENT_FL_TRACEPOINT	= (1 << TRACE_EVENT_FL_TRACEPOINT_BIT),
241 	TRACE_EVENT_FL_KPROBE		= (1 << TRACE_EVENT_FL_KPROBE_BIT),
242 	TRACE_EVENT_FL_UPROBE		= (1 << TRACE_EVENT_FL_UPROBE_BIT),
243 };
244 
245 #define TRACE_EVENT_FL_UKPROBE (TRACE_EVENT_FL_KPROBE | TRACE_EVENT_FL_UPROBE)
246 
247 struct trace_event_call {
248 	struct list_head	list;
249 	struct trace_event_class *class;
250 	union {
251 		char			*name;
252 		/* Set TRACE_EVENT_FL_TRACEPOINT flag when using "tp" */
253 		struct tracepoint	*tp;
254 	};
255 	struct trace_event	event;
256 	char			*print_fmt;
257 	struct event_filter	*filter;
258 	void			*mod;
259 	void			*data;
260 	/*
261 	 *   bit 0:		filter_active
262 	 *   bit 1:		allow trace by non root (cap any)
263 	 *   bit 2:		failed to apply filter
264 	 *   bit 3:		trace internal event (do not enable)
265 	 *   bit 4:		Event was enabled by module
266 	 *   bit 5:		use call filter rather than file filter
267 	 *   bit 6:		Event is a tracepoint
268 	 */
269 	int			flags; /* static flags of different events */
270 
271 #ifdef CONFIG_PERF_EVENTS
272 	int				perf_refcount;
273 	struct hlist_head __percpu	*perf_events;
274 	struct bpf_prog			*prog;
275 	struct perf_event		*bpf_prog_owner;
276 
277 	int	(*perf_perm)(struct trace_event_call *,
278 			     struct perf_event *);
279 #endif
280 };
281 
282 static inline const char *
283 trace_event_name(struct trace_event_call *call)
284 {
285 	if (call->flags & TRACE_EVENT_FL_TRACEPOINT)
286 		return call->tp ? call->tp->name : NULL;
287 	else
288 		return call->name;
289 }
290 
291 struct trace_array;
292 struct trace_subsystem_dir;
293 
294 enum {
295 	EVENT_FILE_FL_ENABLED_BIT,
296 	EVENT_FILE_FL_RECORDED_CMD_BIT,
297 	EVENT_FILE_FL_RECORDED_TGID_BIT,
298 	EVENT_FILE_FL_FILTERED_BIT,
299 	EVENT_FILE_FL_NO_SET_FILTER_BIT,
300 	EVENT_FILE_FL_SOFT_MODE_BIT,
301 	EVENT_FILE_FL_SOFT_DISABLED_BIT,
302 	EVENT_FILE_FL_TRIGGER_MODE_BIT,
303 	EVENT_FILE_FL_TRIGGER_COND_BIT,
304 	EVENT_FILE_FL_PID_FILTER_BIT,
305 	EVENT_FILE_FL_WAS_ENABLED_BIT,
306 };
307 
308 /*
309  * Event file flags:
310  *  ENABLED	  - The event is enabled
311  *  RECORDED_CMD  - The comms should be recorded at sched_switch
312  *  RECORDED_TGID - The tgids should be recorded at sched_switch
313  *  FILTERED	  - The event has a filter attached
314  *  NO_SET_FILTER - Set when filter has error and is to be ignored
315  *  SOFT_MODE     - The event is enabled/disabled by SOFT_DISABLED
316  *  SOFT_DISABLED - When set, do not trace the event (even though its
317  *                   tracepoint may be enabled)
318  *  TRIGGER_MODE  - When set, invoke the triggers associated with the event
319  *  TRIGGER_COND  - When set, one or more triggers has an associated filter
320  *  PID_FILTER    - When set, the event is filtered based on pid
321  *  WAS_ENABLED   - Set when enabled to know to clear trace on module removal
322  */
323 enum {
324 	EVENT_FILE_FL_ENABLED		= (1 << EVENT_FILE_FL_ENABLED_BIT),
325 	EVENT_FILE_FL_RECORDED_CMD	= (1 << EVENT_FILE_FL_RECORDED_CMD_BIT),
326 	EVENT_FILE_FL_RECORDED_TGID	= (1 << EVENT_FILE_FL_RECORDED_TGID_BIT),
327 	EVENT_FILE_FL_FILTERED		= (1 << EVENT_FILE_FL_FILTERED_BIT),
328 	EVENT_FILE_FL_NO_SET_FILTER	= (1 << EVENT_FILE_FL_NO_SET_FILTER_BIT),
329 	EVENT_FILE_FL_SOFT_MODE		= (1 << EVENT_FILE_FL_SOFT_MODE_BIT),
330 	EVENT_FILE_FL_SOFT_DISABLED	= (1 << EVENT_FILE_FL_SOFT_DISABLED_BIT),
331 	EVENT_FILE_FL_TRIGGER_MODE	= (1 << EVENT_FILE_FL_TRIGGER_MODE_BIT),
332 	EVENT_FILE_FL_TRIGGER_COND	= (1 << EVENT_FILE_FL_TRIGGER_COND_BIT),
333 	EVENT_FILE_FL_PID_FILTER	= (1 << EVENT_FILE_FL_PID_FILTER_BIT),
334 	EVENT_FILE_FL_WAS_ENABLED	= (1 << EVENT_FILE_FL_WAS_ENABLED_BIT),
335 };
336 
337 struct trace_event_file {
338 	struct list_head		list;
339 	struct trace_event_call		*event_call;
340 	struct event_filter __rcu	*filter;
341 	struct dentry			*dir;
342 	struct trace_array		*tr;
343 	struct trace_subsystem_dir	*system;
344 	struct list_head		triggers;
345 
346 	/*
347 	 * 32 bit flags:
348 	 *   bit 0:		enabled
349 	 *   bit 1:		enabled cmd record
350 	 *   bit 2:		enable/disable with the soft disable bit
351 	 *   bit 3:		soft disabled
352 	 *   bit 4:		trigger enabled
353 	 *
354 	 * Note: The bits must be set atomically to prevent races
355 	 * from other writers. Reads of flags do not need to be in
356 	 * sync as they occur in critical sections. But the way flags
357 	 * is currently used, these changes do not affect the code
358 	 * except that when a change is made, it may have a slight
359 	 * delay in propagating the changes to other CPUs due to
360 	 * caching and such. Which is mostly OK ;-)
361 	 */
362 	unsigned long		flags;
363 	atomic_t		sm_ref;	/* soft-mode reference counter */
364 	atomic_t		tm_ref;	/* trigger-mode reference counter */
365 };
366 
367 #define __TRACE_EVENT_FLAGS(name, value)				\
368 	static int __init trace_init_flags_##name(void)			\
369 	{								\
370 		event_##name.flags |= value;				\
371 		return 0;						\
372 	}								\
373 	early_initcall(trace_init_flags_##name);
374 
375 #define __TRACE_EVENT_PERF_PERM(name, expr...)				\
376 	static int perf_perm_##name(struct trace_event_call *tp_event, \
377 				    struct perf_event *p_event)		\
378 	{								\
379 		return ({ expr; });					\
380 	}								\
381 	static int __init trace_init_perf_perm_##name(void)		\
382 	{								\
383 		event_##name.perf_perm = &perf_perm_##name;		\
384 		return 0;						\
385 	}								\
386 	early_initcall(trace_init_perf_perm_##name);
387 
388 #define PERF_MAX_TRACE_SIZE	2048
389 
390 #define MAX_FILTER_STR_VAL	256	/* Should handle KSYM_SYMBOL_LEN */
391 
392 enum event_trigger_type {
393 	ETT_NONE		= (0),
394 	ETT_TRACE_ONOFF		= (1 << 0),
395 	ETT_SNAPSHOT		= (1 << 1),
396 	ETT_STACKTRACE		= (1 << 2),
397 	ETT_EVENT_ENABLE	= (1 << 3),
398 	ETT_EVENT_HIST		= (1 << 4),
399 	ETT_HIST_ENABLE		= (1 << 5),
400 };
401 
402 extern int filter_match_preds(struct event_filter *filter, void *rec);
403 
404 extern enum event_trigger_type event_triggers_call(struct trace_event_file *file,
405 						   void *rec);
406 extern void event_triggers_post_call(struct trace_event_file *file,
407 				     enum event_trigger_type tt,
408 				     void *rec);
409 
410 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file);
411 
412 /**
413  * trace_trigger_soft_disabled - do triggers and test if soft disabled
414  * @file: The file pointer of the event to test
415  *
416  * If any triggers without filters are attached to this event, they
417  * will be called here. If the event is soft disabled and has no
418  * triggers that require testing the fields, it will return true,
419  * otherwise false.
420  */
421 static inline bool
422 trace_trigger_soft_disabled(struct trace_event_file *file)
423 {
424 	unsigned long eflags = file->flags;
425 
426 	if (!(eflags & EVENT_FILE_FL_TRIGGER_COND)) {
427 		if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
428 			event_triggers_call(file, NULL);
429 		if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
430 			return true;
431 		if (eflags & EVENT_FILE_FL_PID_FILTER)
432 			return trace_event_ignore_this_pid(file);
433 	}
434 	return false;
435 }
436 
437 #ifdef CONFIG_BPF_EVENTS
438 unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx);
439 #else
440 static inline unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
441 {
442 	return 1;
443 }
444 #endif
445 
446 enum {
447 	FILTER_OTHER = 0,
448 	FILTER_STATIC_STRING,
449 	FILTER_DYN_STRING,
450 	FILTER_PTR_STRING,
451 	FILTER_TRACE_FN,
452 	FILTER_COMM,
453 	FILTER_CPU,
454 };
455 
456 extern int trace_event_raw_init(struct trace_event_call *call);
457 extern int trace_define_field(struct trace_event_call *call, const char *type,
458 			      const char *name, int offset, int size,
459 			      int is_signed, int filter_type);
460 extern int trace_add_event_call(struct trace_event_call *call);
461 extern int trace_remove_event_call(struct trace_event_call *call);
462 extern int trace_event_get_offsets(struct trace_event_call *call);
463 
464 #define is_signed_type(type)	(((type)(-1)) < (type)1)
465 
466 int trace_set_clr_event(const char *system, const char *event, int set);
467 
468 /*
469  * The double __builtin_constant_p is because gcc will give us an error
470  * if we try to allocate the static variable to fmt if it is not a
471  * constant. Even with the outer if statement optimizing out.
472  */
473 #define event_trace_printk(ip, fmt, args...)				\
474 do {									\
475 	__trace_printk_check_format(fmt, ##args);			\
476 	tracing_record_cmdline(current);				\
477 	if (__builtin_constant_p(fmt)) {				\
478 		static const char *trace_printk_fmt			\
479 		  __attribute__((section("__trace_printk_fmt"))) =	\
480 			__builtin_constant_p(fmt) ? fmt : NULL;		\
481 									\
482 		__trace_bprintk(ip, trace_printk_fmt, ##args);		\
483 	} else								\
484 		__trace_printk(ip, fmt, ##args);			\
485 } while (0)
486 
487 #ifdef CONFIG_PERF_EVENTS
488 struct perf_event;
489 
490 DECLARE_PER_CPU(struct pt_regs, perf_trace_regs);
491 
492 extern int  perf_trace_init(struct perf_event *event);
493 extern void perf_trace_destroy(struct perf_event *event);
494 extern int  perf_trace_add(struct perf_event *event, int flags);
495 extern void perf_trace_del(struct perf_event *event, int flags);
496 extern int  ftrace_profile_set_filter(struct perf_event *event, int event_id,
497 				     char *filter_str);
498 extern void ftrace_profile_free_filter(struct perf_event *event);
499 void perf_trace_buf_update(void *record, u16 type);
500 void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp);
501 
502 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
503 			       struct trace_event_call *call, u64 count,
504 			       struct pt_regs *regs, struct hlist_head *head,
505 			       struct task_struct *task);
506 
507 static inline void
508 perf_trace_buf_submit(void *raw_data, int size, int rctx, u16 type,
509 		       u64 count, struct pt_regs *regs, void *head,
510 		       struct task_struct *task, struct perf_event *event)
511 {
512 	perf_tp_event(type, count, raw_data, size, regs, head, rctx, task, event);
513 }
514 #endif
515 
516 #endif /* _LINUX_TRACE_EVENT_H */
517