xref: /openbmc/linux/kernel/trace/trace.h (revision e8e0929d)
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 
15 #include <linux/trace_seq.h>
16 #include <linux/ftrace_event.h>
17 
18 enum trace_type {
19 	__TRACE_FIRST_TYPE = 0,
20 
21 	TRACE_FN,
22 	TRACE_CTX,
23 	TRACE_WAKE,
24 	TRACE_STACK,
25 	TRACE_PRINT,
26 	TRACE_BPRINT,
27 	TRACE_SPECIAL,
28 	TRACE_MMIO_RW,
29 	TRACE_MMIO_MAP,
30 	TRACE_BRANCH,
31 	TRACE_BOOT_CALL,
32 	TRACE_BOOT_RET,
33 	TRACE_GRAPH_RET,
34 	TRACE_GRAPH_ENT,
35 	TRACE_USER_STACK,
36 	TRACE_HW_BRANCHES,
37 	TRACE_KMEM_ALLOC,
38 	TRACE_KMEM_FREE,
39 	TRACE_BLK,
40 
41 	__TRACE_LAST_TYPE,
42 };
43 
44 enum kmemtrace_type_id {
45 	KMEMTRACE_TYPE_KMALLOC = 0,	/* kmalloc() or kfree(). */
46 	KMEMTRACE_TYPE_CACHE,		/* kmem_cache_*(). */
47 	KMEMTRACE_TYPE_PAGES,		/* __get_free_pages() and friends. */
48 };
49 
50 extern struct tracer boot_tracer;
51 
52 #undef __field
53 #define __field(type, item)		type	item;
54 
55 #undef __field_struct
56 #define __field_struct(type, item)	__field(type, item)
57 
58 #undef __field_desc
59 #define __field_desc(type, container, item)
60 
61 #undef __array
62 #define __array(type, item, size)	type	item[size];
63 
64 #undef __array_desc
65 #define __array_desc(type, container, item, size)
66 
67 #undef __dynamic_array
68 #define __dynamic_array(type, item)	type	item[];
69 
70 #undef F_STRUCT
71 #define F_STRUCT(args...)		args
72 
73 #undef FTRACE_ENTRY
74 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)	\
75 	struct struct_name {					\
76 		struct trace_entry	ent;			\
77 		tstruct						\
78 	}
79 
80 #undef TP_ARGS
81 #define TP_ARGS(args...)	args
82 
83 #undef FTRACE_ENTRY_DUP
84 #define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)
85 
86 #include "trace_entries.h"
87 
88 /*
89  * syscalls are special, and need special handling, this is why
90  * they are not included in trace_entries.h
91  */
92 struct syscall_trace_enter {
93 	struct trace_entry	ent;
94 	int			nr;
95 	unsigned long		args[];
96 };
97 
98 struct syscall_trace_exit {
99 	struct trace_entry	ent;
100 	int			nr;
101 	unsigned long		ret;
102 };
103 
104 /*
105  * trace_flag_type is an enumeration that holds different
106  * states when a trace occurs. These are:
107  *  IRQS_OFF		- interrupts were disabled
108  *  IRQS_NOSUPPORT	- arch does not support irqs_disabled_flags
109  *  NEED_RESCHED	- reschedule is requested
110  *  HARDIRQ		- inside an interrupt handler
111  *  SOFTIRQ		- inside a softirq handler
112  */
113 enum trace_flag_type {
114 	TRACE_FLAG_IRQS_OFF		= 0x01,
115 	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
116 	TRACE_FLAG_NEED_RESCHED		= 0x04,
117 	TRACE_FLAG_HARDIRQ		= 0x08,
118 	TRACE_FLAG_SOFTIRQ		= 0x10,
119 };
120 
121 #define TRACE_BUF_SIZE		1024
122 
123 /*
124  * The CPU trace array - it consists of thousands of trace entries
125  * plus some other descriptor data: (for example which task started
126  * the trace, etc.)
127  */
128 struct trace_array_cpu {
129 	atomic_t		disabled;
130 	void			*buffer_page;	/* ring buffer spare */
131 
132 	unsigned long		saved_latency;
133 	unsigned long		critical_start;
134 	unsigned long		critical_end;
135 	unsigned long		critical_sequence;
136 	unsigned long		nice;
137 	unsigned long		policy;
138 	unsigned long		rt_priority;
139 	unsigned long		skipped_entries;
140 	cycle_t			preempt_timestamp;
141 	pid_t			pid;
142 	uid_t			uid;
143 	char			comm[TASK_COMM_LEN];
144 };
145 
146 /*
147  * The trace array - an array of per-CPU trace arrays. This is the
148  * highest level data structure that individual tracers deal with.
149  * They have on/off state as well:
150  */
151 struct trace_array {
152 	struct ring_buffer	*buffer;
153 	unsigned long		entries;
154 	int			cpu;
155 	cycle_t			time_start;
156 	struct task_struct	*waiter;
157 	struct trace_array_cpu	*data[NR_CPUS];
158 };
159 
160 #define FTRACE_CMP_TYPE(var, type) \
161 	__builtin_types_compatible_p(typeof(var), type *)
162 
163 #undef IF_ASSIGN
164 #define IF_ASSIGN(var, entry, etype, id)		\
165 	if (FTRACE_CMP_TYPE(var, etype)) {		\
166 		var = (typeof(var))(entry);		\
167 		WARN_ON(id && (entry)->type != id);	\
168 		break;					\
169 	}
170 
171 /* Will cause compile errors if type is not found. */
172 extern void __ftrace_bad_type(void);
173 
174 /*
175  * The trace_assign_type is a verifier that the entry type is
176  * the same as the type being assigned. To add new types simply
177  * add a line with the following format:
178  *
179  * IF_ASSIGN(var, ent, type, id);
180  *
181  *  Where "type" is the trace type that includes the trace_entry
182  *  as the "ent" item. And "id" is the trace identifier that is
183  *  used in the trace_type enum.
184  *
185  *  If the type can have more than one id, then use zero.
186  */
187 #define trace_assign_type(var, ent)					\
188 	do {								\
189 		IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);	\
190 		IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);	\
191 		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
192 		IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
193 		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
194 		IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT);	\
195 		IF_ASSIGN(var, ent, struct special_entry, 0);		\
196 		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
197 			  TRACE_MMIO_RW);				\
198 		IF_ASSIGN(var, ent, struct trace_mmiotrace_map,		\
199 			  TRACE_MMIO_MAP);				\
200 		IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
201 		IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
202 		IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
203 		IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,	\
204 			  TRACE_GRAPH_ENT);		\
205 		IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,	\
206 			  TRACE_GRAPH_RET);		\
207 		IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
208 		IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,	\
209 			  TRACE_KMEM_ALLOC);	\
210 		IF_ASSIGN(var, ent, struct kmemtrace_free_entry,	\
211 			  TRACE_KMEM_FREE);	\
212 		__ftrace_bad_type();					\
213 	} while (0)
214 
215 /*
216  * An option specific to a tracer. This is a boolean value.
217  * The bit is the bit index that sets its value on the
218  * flags value in struct tracer_flags.
219  */
220 struct tracer_opt {
221 	const char	*name; /* Will appear on the trace_options file */
222 	u32		bit; /* Mask assigned in val field in tracer_flags */
223 };
224 
225 /*
226  * The set of specific options for a tracer. Your tracer
227  * have to set the initial value of the flags val.
228  */
229 struct tracer_flags {
230 	u32			val;
231 	struct tracer_opt	*opts;
232 };
233 
234 /* Makes more easy to define a tracer opt */
235 #define TRACER_OPT(s, b)	.name = #s, .bit = b
236 
237 
238 /**
239  * struct tracer - a specific tracer and its callbacks to interact with debugfs
240  * @name: the name chosen to select it on the available_tracers file
241  * @init: called when one switches to this tracer (echo name > current_tracer)
242  * @reset: called when one switches to another tracer
243  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
244  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
245  * @open: called when the trace file is opened
246  * @pipe_open: called when the trace_pipe file is opened
247  * @wait_pipe: override how the user waits for traces on trace_pipe
248  * @close: called when the trace file is released
249  * @read: override the default read callback on trace_pipe
250  * @splice_read: override the default splice_read callback on trace_pipe
251  * @selftest: selftest to run on boot (see trace_selftest.c)
252  * @print_headers: override the first lines that describe your columns
253  * @print_line: callback that prints a trace
254  * @set_flag: signals one of your private flags changed (trace_options file)
255  * @flags: your private flags
256  */
257 struct tracer {
258 	const char		*name;
259 	int			(*init)(struct trace_array *tr);
260 	void			(*reset)(struct trace_array *tr);
261 	void			(*start)(struct trace_array *tr);
262 	void			(*stop)(struct trace_array *tr);
263 	void			(*open)(struct trace_iterator *iter);
264 	void			(*pipe_open)(struct trace_iterator *iter);
265 	void			(*wait_pipe)(struct trace_iterator *iter);
266 	void			(*close)(struct trace_iterator *iter);
267 	ssize_t			(*read)(struct trace_iterator *iter,
268 					struct file *filp, char __user *ubuf,
269 					size_t cnt, loff_t *ppos);
270 	ssize_t			(*splice_read)(struct trace_iterator *iter,
271 					       struct file *filp,
272 					       loff_t *ppos,
273 					       struct pipe_inode_info *pipe,
274 					       size_t len,
275 					       unsigned int flags);
276 #ifdef CONFIG_FTRACE_STARTUP_TEST
277 	int			(*selftest)(struct tracer *trace,
278 					    struct trace_array *tr);
279 #endif
280 	void			(*print_header)(struct seq_file *m);
281 	enum print_line_t	(*print_line)(struct trace_iterator *iter);
282 	/* If you handled the flag setting, return 0 */
283 	int			(*set_flag)(u32 old_flags, u32 bit, int set);
284 	struct tracer		*next;
285 	int			print_max;
286 	struct tracer_flags	*flags;
287 };
288 
289 
290 #define TRACE_PIPE_ALL_CPU	-1
291 
292 int tracer_init(struct tracer *t, struct trace_array *tr);
293 int tracing_is_enabled(void);
294 void trace_wake_up(void);
295 void tracing_reset(struct trace_array *tr, int cpu);
296 void tracing_reset_online_cpus(struct trace_array *tr);
297 void tracing_reset_current(int cpu);
298 void tracing_reset_current_online_cpus(void);
299 int tracing_open_generic(struct inode *inode, struct file *filp);
300 struct dentry *trace_create_file(const char *name,
301 				 mode_t mode,
302 				 struct dentry *parent,
303 				 void *data,
304 				 const struct file_operations *fops);
305 
306 struct dentry *tracing_init_dentry(void);
307 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
308 
309 struct ring_buffer_event;
310 
311 struct ring_buffer_event *
312 trace_buffer_lock_reserve(struct ring_buffer *buffer,
313 			  int type,
314 			  unsigned long len,
315 			  unsigned long flags,
316 			  int pc);
317 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
318 				struct ring_buffer_event *event,
319 				unsigned long flags, int pc);
320 
321 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
322 						struct trace_array_cpu *data);
323 
324 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
325 					  int *ent_cpu, u64 *ent_ts);
326 
327 void default_wait_pipe(struct trace_iterator *iter);
328 void poll_wait_pipe(struct trace_iterator *iter);
329 
330 void ftrace(struct trace_array *tr,
331 			    struct trace_array_cpu *data,
332 			    unsigned long ip,
333 			    unsigned long parent_ip,
334 			    unsigned long flags, int pc);
335 void tracing_sched_switch_trace(struct trace_array *tr,
336 				struct task_struct *prev,
337 				struct task_struct *next,
338 				unsigned long flags, int pc);
339 
340 void tracing_sched_wakeup_trace(struct trace_array *tr,
341 				struct task_struct *wakee,
342 				struct task_struct *cur,
343 				unsigned long flags, int pc);
344 void trace_special(struct trace_array *tr,
345 		   struct trace_array_cpu *data,
346 		   unsigned long arg1,
347 		   unsigned long arg2,
348 		   unsigned long arg3, int pc);
349 void trace_function(struct trace_array *tr,
350 		    unsigned long ip,
351 		    unsigned long parent_ip,
352 		    unsigned long flags, int pc);
353 
354 void trace_graph_return(struct ftrace_graph_ret *trace);
355 int trace_graph_entry(struct ftrace_graph_ent *trace);
356 void set_graph_array(struct trace_array *tr);
357 
358 void tracing_start_cmdline_record(void);
359 void tracing_stop_cmdline_record(void);
360 void tracing_sched_switch_assign_trace(struct trace_array *tr);
361 void tracing_stop_sched_switch_record(void);
362 void tracing_start_sched_switch_record(void);
363 int register_tracer(struct tracer *type);
364 void unregister_tracer(struct tracer *type);
365 int is_tracing_stopped(void);
366 
367 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
368 
369 #ifdef CONFIG_TRACER_MAX_TRACE
370 extern unsigned long tracing_max_latency;
371 extern unsigned long tracing_thresh;
372 
373 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
374 void update_max_tr_single(struct trace_array *tr,
375 			  struct task_struct *tsk, int cpu);
376 #endif /* CONFIG_TRACER_MAX_TRACE */
377 
378 #ifdef CONFIG_STACKTRACE
379 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
380 			int skip, int pc);
381 
382 void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
383 			    int pc);
384 
385 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
386 		   int pc);
387 #else
388 static inline void ftrace_trace_stack(struct trace_array *tr,
389 				      unsigned long flags, int skip, int pc)
390 {
391 }
392 
393 static inline void ftrace_trace_userstack(struct trace_array *tr,
394 					  unsigned long flags, int pc)
395 {
396 }
397 
398 static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
399 				 int skip, int pc)
400 {
401 }
402 #endif /* CONFIG_STACKTRACE */
403 
404 extern cycle_t ftrace_now(int cpu);
405 
406 extern void trace_find_cmdline(int pid, char comm[]);
407 
408 #ifdef CONFIG_DYNAMIC_FTRACE
409 extern unsigned long ftrace_update_tot_cnt;
410 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
411 extern int DYN_FTRACE_TEST_NAME(void);
412 #endif
413 
414 extern int ring_buffer_expanded;
415 extern bool tracing_selftest_disabled;
416 DECLARE_PER_CPU(local_t, ftrace_cpu_disabled);
417 
418 #ifdef CONFIG_FTRACE_STARTUP_TEST
419 extern int trace_selftest_startup_function(struct tracer *trace,
420 					   struct trace_array *tr);
421 extern int trace_selftest_startup_function_graph(struct tracer *trace,
422 						 struct trace_array *tr);
423 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
424 					  struct trace_array *tr);
425 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
426 					     struct trace_array *tr);
427 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
428 						 struct trace_array *tr);
429 extern int trace_selftest_startup_wakeup(struct tracer *trace,
430 					 struct trace_array *tr);
431 extern int trace_selftest_startup_nop(struct tracer *trace,
432 					 struct trace_array *tr);
433 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
434 					       struct trace_array *tr);
435 extern int trace_selftest_startup_sysprof(struct tracer *trace,
436 					       struct trace_array *tr);
437 extern int trace_selftest_startup_branch(struct tracer *trace,
438 					 struct trace_array *tr);
439 extern int trace_selftest_startup_hw_branches(struct tracer *trace,
440 					      struct trace_array *tr);
441 #endif /* CONFIG_FTRACE_STARTUP_TEST */
442 
443 extern void *head_page(struct trace_array_cpu *data);
444 extern unsigned long long ns2usecs(cycle_t nsec);
445 extern int
446 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
447 extern int
448 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
449 extern int
450 trace_array_vprintk(struct trace_array *tr,
451 		    unsigned long ip, const char *fmt, va_list args);
452 int trace_array_printk(struct trace_array *tr,
453 		       unsigned long ip, const char *fmt, ...);
454 
455 extern unsigned long trace_flags;
456 
457 extern int trace_clock_id;
458 
459 /* Standard output formatting function used for function return traces */
460 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
461 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
462 extern enum print_line_t
463 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
464 
465 #ifdef CONFIG_DYNAMIC_FTRACE
466 /* TODO: make this variable */
467 #define FTRACE_GRAPH_MAX_FUNCS		32
468 extern int ftrace_graph_count;
469 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
470 
471 static inline int ftrace_graph_addr(unsigned long addr)
472 {
473 	int i;
474 
475 	if (!ftrace_graph_count || test_tsk_trace_graph(current))
476 		return 1;
477 
478 	for (i = 0; i < ftrace_graph_count; i++) {
479 		if (addr == ftrace_graph_funcs[i])
480 			return 1;
481 	}
482 
483 	return 0;
484 }
485 #else
486 static inline int ftrace_trace_addr(unsigned long addr)
487 {
488 	return 1;
489 }
490 static inline int ftrace_graph_addr(unsigned long addr)
491 {
492 	return 1;
493 }
494 #endif /* CONFIG_DYNAMIC_FTRACE */
495 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
496 static inline enum print_line_t
497 print_graph_function(struct trace_iterator *iter)
498 {
499 	return TRACE_TYPE_UNHANDLED;
500 }
501 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
502 
503 extern struct pid *ftrace_pid_trace;
504 
505 #ifdef CONFIG_FUNCTION_TRACER
506 static inline int ftrace_trace_task(struct task_struct *task)
507 {
508 	if (!ftrace_pid_trace)
509 		return 1;
510 
511 	return test_tsk_trace_trace(task);
512 }
513 #else
514 static inline int ftrace_trace_task(struct task_struct *task)
515 {
516 	return 1;
517 }
518 #endif
519 
520 /*
521  * struct trace_parser - servers for reading the user input separated by spaces
522  * @cont: set if the input is not complete - no final space char was found
523  * @buffer: holds the parsed user input
524  * @idx: user input lenght
525  * @size: buffer size
526  */
527 struct trace_parser {
528 	bool		cont;
529 	char		*buffer;
530 	unsigned	idx;
531 	unsigned	size;
532 };
533 
534 static inline bool trace_parser_loaded(struct trace_parser *parser)
535 {
536 	return (parser->idx != 0);
537 }
538 
539 static inline bool trace_parser_cont(struct trace_parser *parser)
540 {
541 	return parser->cont;
542 }
543 
544 static inline void trace_parser_clear(struct trace_parser *parser)
545 {
546 	parser->cont = false;
547 	parser->idx = 0;
548 }
549 
550 extern int trace_parser_get_init(struct trace_parser *parser, int size);
551 extern void trace_parser_put(struct trace_parser *parser);
552 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
553 	size_t cnt, loff_t *ppos);
554 
555 /*
556  * trace_iterator_flags is an enumeration that defines bit
557  * positions into trace_flags that controls the output.
558  *
559  * NOTE: These bits must match the trace_options array in
560  *       trace.c.
561  */
562 enum trace_iterator_flags {
563 	TRACE_ITER_PRINT_PARENT		= 0x01,
564 	TRACE_ITER_SYM_OFFSET		= 0x02,
565 	TRACE_ITER_SYM_ADDR		= 0x04,
566 	TRACE_ITER_VERBOSE		= 0x08,
567 	TRACE_ITER_RAW			= 0x10,
568 	TRACE_ITER_HEX			= 0x20,
569 	TRACE_ITER_BIN			= 0x40,
570 	TRACE_ITER_BLOCK		= 0x80,
571 	TRACE_ITER_STACKTRACE		= 0x100,
572 	TRACE_ITER_SCHED_TREE		= 0x200,
573 	TRACE_ITER_PRINTK		= 0x400,
574 	TRACE_ITER_PREEMPTONLY		= 0x800,
575 	TRACE_ITER_BRANCH		= 0x1000,
576 	TRACE_ITER_ANNOTATE		= 0x2000,
577 	TRACE_ITER_USERSTACKTRACE       = 0x4000,
578 	TRACE_ITER_SYM_USEROBJ          = 0x8000,
579 	TRACE_ITER_PRINTK_MSGONLY	= 0x10000,
580 	TRACE_ITER_CONTEXT_INFO		= 0x20000, /* Print pid/cpu/time */
581 	TRACE_ITER_LATENCY_FMT		= 0x40000,
582 	TRACE_ITER_SLEEP_TIME		= 0x80000,
583 	TRACE_ITER_GRAPH_TIME		= 0x100000,
584 };
585 
586 /*
587  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
588  * control the output of kernel symbols.
589  */
590 #define TRACE_ITER_SYM_MASK \
591 	(TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
592 
593 extern struct tracer nop_trace;
594 
595 /**
596  * ftrace_preempt_disable - disable preemption scheduler safe
597  *
598  * When tracing can happen inside the scheduler, there exists
599  * cases that the tracing might happen before the need_resched
600  * flag is checked. If this happens and the tracer calls
601  * preempt_enable (after a disable), a schedule might take place
602  * causing an infinite recursion.
603  *
604  * To prevent this, we read the need_resched flag before
605  * disabling preemption. When we want to enable preemption we
606  * check the flag, if it is set, then we call preempt_enable_no_resched.
607  * Otherwise, we call preempt_enable.
608  *
609  * The rational for doing the above is that if need_resched is set
610  * and we have yet to reschedule, we are either in an atomic location
611  * (where we do not need to check for scheduling) or we are inside
612  * the scheduler and do not want to resched.
613  */
614 static inline int ftrace_preempt_disable(void)
615 {
616 	int resched;
617 
618 	resched = need_resched();
619 	preempt_disable_notrace();
620 
621 	return resched;
622 }
623 
624 /**
625  * ftrace_preempt_enable - enable preemption scheduler safe
626  * @resched: the return value from ftrace_preempt_disable
627  *
628  * This is a scheduler safe way to enable preemption and not miss
629  * any preemption checks. The disabled saved the state of preemption.
630  * If resched is set, then we are either inside an atomic or
631  * are inside the scheduler (we would have already scheduled
632  * otherwise). In this case, we do not want to call normal
633  * preempt_enable, but preempt_enable_no_resched instead.
634  */
635 static inline void ftrace_preempt_enable(int resched)
636 {
637 	if (resched)
638 		preempt_enable_no_resched_notrace();
639 	else
640 		preempt_enable_notrace();
641 }
642 
643 #ifdef CONFIG_BRANCH_TRACER
644 extern int enable_branch_tracing(struct trace_array *tr);
645 extern void disable_branch_tracing(void);
646 static inline int trace_branch_enable(struct trace_array *tr)
647 {
648 	if (trace_flags & TRACE_ITER_BRANCH)
649 		return enable_branch_tracing(tr);
650 	return 0;
651 }
652 static inline void trace_branch_disable(void)
653 {
654 	/* due to races, always disable */
655 	disable_branch_tracing();
656 }
657 #else
658 static inline int trace_branch_enable(struct trace_array *tr)
659 {
660 	return 0;
661 }
662 static inline void trace_branch_disable(void)
663 {
664 }
665 #endif /* CONFIG_BRANCH_TRACER */
666 
667 /* set ring buffers to default size if not already done so */
668 int tracing_update_buffers(void);
669 
670 /* trace event type bit fields, not numeric */
671 enum {
672 	TRACE_EVENT_TYPE_PRINTF		= 1,
673 	TRACE_EVENT_TYPE_RAW		= 2,
674 };
675 
676 struct ftrace_event_field {
677 	struct list_head	link;
678 	char			*name;
679 	char			*type;
680 	int			filter_type;
681 	int			offset;
682 	int			size;
683 	int			is_signed;
684 };
685 
686 struct event_filter {
687 	int			n_preds;
688 	struct filter_pred	**preds;
689 	char			*filter_string;
690 	bool			no_reset;
691 };
692 
693 struct event_subsystem {
694 	struct list_head	list;
695 	const char		*name;
696 	struct dentry		*entry;
697 	struct event_filter	*filter;
698 	int			nr_events;
699 };
700 
701 struct filter_pred;
702 
703 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
704 				 int val1, int val2);
705 
706 struct filter_pred {
707 	filter_pred_fn_t fn;
708 	u64 val;
709 	char str_val[MAX_FILTER_STR_VAL];
710 	int str_len;
711 	char *field_name;
712 	int offset;
713 	int not;
714 	int op;
715 	int pop_n;
716 };
717 
718 extern void print_event_filter(struct ftrace_event_call *call,
719 			       struct trace_seq *s);
720 extern int apply_event_filter(struct ftrace_event_call *call,
721 			      char *filter_string);
722 extern int apply_subsystem_event_filter(struct event_subsystem *system,
723 					char *filter_string);
724 extern void print_subsystem_event_filter(struct event_subsystem *system,
725 					 struct trace_seq *s);
726 extern int filter_assign_type(const char *type);
727 
728 static inline int
729 filter_check_discard(struct ftrace_event_call *call, void *rec,
730 		     struct ring_buffer *buffer,
731 		     struct ring_buffer_event *event)
732 {
733 	if (unlikely(call->filter_active) && !filter_match_preds(call, rec)) {
734 		ring_buffer_discard_commit(buffer, event);
735 		return 1;
736 	}
737 
738 	return 0;
739 }
740 
741 extern struct mutex event_mutex;
742 extern struct list_head ftrace_events;
743 
744 extern const char *__start___trace_bprintk_fmt[];
745 extern const char *__stop___trace_bprintk_fmt[];
746 
747 #undef FTRACE_ENTRY
748 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print)		\
749 	extern struct ftrace_event_call event_##call;
750 #undef FTRACE_ENTRY_DUP
751 #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)		\
752 	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
753 #include "trace_entries.h"
754 
755 #endif /* _LINUX_KERNEL_TRACE_H */
756