tracing/filters: move preds into event_filter object
[linux-2.6.git] / kernel / trace / trace.h
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/ftrace.h>
11 #include <trace/boot.h>
12 #include <linux/kmemtrace.h>
13 #include <trace/power.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_SYSCALL_ENTER,
38         TRACE_SYSCALL_EXIT,
39         TRACE_KMEM_ALLOC,
40         TRACE_KMEM_FREE,
41         TRACE_POWER,
42         TRACE_BLK,
43
44         __TRACE_LAST_TYPE,
45 };
46
47 /*
48  * Function trace entry - function address and parent function addres:
49  */
50 struct ftrace_entry {
51         struct trace_entry      ent;
52         unsigned long           ip;
53         unsigned long           parent_ip;
54 };
55
56 /* Function call entry */
57 struct ftrace_graph_ent_entry {
58         struct trace_entry              ent;
59         struct ftrace_graph_ent         graph_ent;
60 };
61
62 /* Function return entry */
63 struct ftrace_graph_ret_entry {
64         struct trace_entry              ent;
65         struct ftrace_graph_ret         ret;
66 };
67 extern struct tracer boot_tracer;
68
69 /*
70  * Context switch trace entry - which task (and prio) we switched from/to:
71  */
72 struct ctx_switch_entry {
73         struct trace_entry      ent;
74         unsigned int            prev_pid;
75         unsigned char           prev_prio;
76         unsigned char           prev_state;
77         unsigned int            next_pid;
78         unsigned char           next_prio;
79         unsigned char           next_state;
80         unsigned int            next_cpu;
81 };
82
83 /*
84  * Special (free-form) trace entry:
85  */
86 struct special_entry {
87         struct trace_entry      ent;
88         unsigned long           arg1;
89         unsigned long           arg2;
90         unsigned long           arg3;
91 };
92
93 /*
94  * Stack-trace entry:
95  */
96
97 #define FTRACE_STACK_ENTRIES    8
98
99 struct stack_entry {
100         struct trace_entry      ent;
101         unsigned long           caller[FTRACE_STACK_ENTRIES];
102 };
103
104 struct userstack_entry {
105         struct trace_entry      ent;
106         unsigned long           caller[FTRACE_STACK_ENTRIES];
107 };
108
109 /*
110  * trace_printk entry:
111  */
112 struct bprint_entry {
113         struct trace_entry      ent;
114         unsigned long           ip;
115         const char              *fmt;
116         u32                     buf[];
117 };
118
119 struct print_entry {
120         struct trace_entry      ent;
121         unsigned long           ip;
122         char                    buf[];
123 };
124
125 #define TRACE_OLD_SIZE          88
126
127 struct trace_field_cont {
128         unsigned char           type;
129         /* Temporary till we get rid of this completely */
130         char                    buf[TRACE_OLD_SIZE - 1];
131 };
132
133 struct trace_mmiotrace_rw {
134         struct trace_entry      ent;
135         struct mmiotrace_rw     rw;
136 };
137
138 struct trace_mmiotrace_map {
139         struct trace_entry      ent;
140         struct mmiotrace_map    map;
141 };
142
143 struct trace_boot_call {
144         struct trace_entry      ent;
145         struct boot_trace_call boot_call;
146 };
147
148 struct trace_boot_ret {
149         struct trace_entry      ent;
150         struct boot_trace_ret boot_ret;
151 };
152
153 #define TRACE_FUNC_SIZE 30
154 #define TRACE_FILE_SIZE 20
155 struct trace_branch {
156         struct trace_entry      ent;
157         unsigned                line;
158         char                    func[TRACE_FUNC_SIZE+1];
159         char                    file[TRACE_FILE_SIZE+1];
160         char                    correct;
161 };
162
163 struct hw_branch_entry {
164         struct trace_entry      ent;
165         u64                     from;
166         u64                     to;
167 };
168
169 struct trace_power {
170         struct trace_entry      ent;
171         struct power_trace      state_data;
172 };
173
174 enum kmemtrace_type_id {
175         KMEMTRACE_TYPE_KMALLOC = 0,     /* kmalloc() or kfree(). */
176         KMEMTRACE_TYPE_CACHE,           /* kmem_cache_*(). */
177         KMEMTRACE_TYPE_PAGES,           /* __get_free_pages() and friends. */
178 };
179
180 struct kmemtrace_alloc_entry {
181         struct trace_entry      ent;
182         enum kmemtrace_type_id type_id;
183         unsigned long call_site;
184         const void *ptr;
185         size_t bytes_req;
186         size_t bytes_alloc;
187         gfp_t gfp_flags;
188         int node;
189 };
190
191 struct kmemtrace_free_entry {
192         struct trace_entry      ent;
193         enum kmemtrace_type_id type_id;
194         unsigned long call_site;
195         const void *ptr;
196 };
197
198 struct syscall_trace_enter {
199         struct trace_entry      ent;
200         int                     nr;
201         unsigned long           args[];
202 };
203
204 struct syscall_trace_exit {
205         struct trace_entry      ent;
206         int                     nr;
207         unsigned long           ret;
208 };
209
210
211 /*
212  * trace_flag_type is an enumeration that holds different
213  * states when a trace occurs. These are:
214  *  IRQS_OFF            - interrupts were disabled
215  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
216  *  NEED_RESCED         - reschedule is requested
217  *  HARDIRQ             - inside an interrupt handler
218  *  SOFTIRQ             - inside a softirq handler
219  */
220 enum trace_flag_type {
221         TRACE_FLAG_IRQS_OFF             = 0x01,
222         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
223         TRACE_FLAG_NEED_RESCHED         = 0x04,
224         TRACE_FLAG_HARDIRQ              = 0x08,
225         TRACE_FLAG_SOFTIRQ              = 0x10,
226 };
227
228 #define TRACE_BUF_SIZE          1024
229
230 /*
231  * The CPU trace array - it consists of thousands of trace entries
232  * plus some other descriptor data: (for example which task started
233  * the trace, etc.)
234  */
235 struct trace_array_cpu {
236         atomic_t                disabled;
237         void                    *buffer_page;   /* ring buffer spare */
238
239         /* these fields get copied into max-trace: */
240         unsigned long           trace_idx;
241         unsigned long           overrun;
242         unsigned long           saved_latency;
243         unsigned long           critical_start;
244         unsigned long           critical_end;
245         unsigned long           critical_sequence;
246         unsigned long           nice;
247         unsigned long           policy;
248         unsigned long           rt_priority;
249         cycle_t                 preempt_timestamp;
250         pid_t                   pid;
251         uid_t                   uid;
252         char                    comm[TASK_COMM_LEN];
253 };
254
255 /*
256  * The trace array - an array of per-CPU trace arrays. This is the
257  * highest level data structure that individual tracers deal with.
258  * They have on/off state as well:
259  */
260 struct trace_array {
261         struct ring_buffer      *buffer;
262         unsigned long           entries;
263         int                     cpu;
264         cycle_t                 time_start;
265         struct task_struct      *waiter;
266         struct trace_array_cpu  *data[NR_CPUS];
267 };
268
269 #define FTRACE_CMP_TYPE(var, type) \
270         __builtin_types_compatible_p(typeof(var), type *)
271
272 #undef IF_ASSIGN
273 #define IF_ASSIGN(var, entry, etype, id)                \
274         if (FTRACE_CMP_TYPE(var, etype)) {              \
275                 var = (typeof(var))(entry);             \
276                 WARN_ON(id && (entry)->type != id);     \
277                 break;                                  \
278         }
279
280 /* Will cause compile errors if type is not found. */
281 extern void __ftrace_bad_type(void);
282
283 /*
284  * The trace_assign_type is a verifier that the entry type is
285  * the same as the type being assigned. To add new types simply
286  * add a line with the following format:
287  *
288  * IF_ASSIGN(var, ent, type, id);
289  *
290  *  Where "type" is the trace type that includes the trace_entry
291  *  as the "ent" item. And "id" is the trace identifier that is
292  *  used in the trace_type enum.
293  *
294  *  If the type can have more than one id, then use zero.
295  */
296 #define trace_assign_type(var, ent)                                     \
297         do {                                                            \
298                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
299                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
300                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
301                 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
302                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
303                 IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT); \
304                 IF_ASSIGN(var, ent, struct special_entry, 0);           \
305                 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
306                           TRACE_MMIO_RW);                               \
307                 IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
308                           TRACE_MMIO_MAP);                              \
309                 IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
310                 IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
311                 IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
312                 IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,      \
313                           TRACE_GRAPH_ENT);             \
314                 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,      \
315                           TRACE_GRAPH_RET);             \
316                 IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
317                 IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
318                 IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,       \
319                           TRACE_KMEM_ALLOC);    \
320                 IF_ASSIGN(var, ent, struct kmemtrace_free_entry,        \
321                           TRACE_KMEM_FREE);     \
322                 IF_ASSIGN(var, ent, struct syscall_trace_enter,         \
323                           TRACE_SYSCALL_ENTER);                         \
324                 IF_ASSIGN(var, ent, struct syscall_trace_exit,          \
325                           TRACE_SYSCALL_EXIT);                          \
326                 __ftrace_bad_type();                                    \
327         } while (0)
328
329 /*
330  * An option specific to a tracer. This is a boolean value.
331  * The bit is the bit index that sets its value on the
332  * flags value in struct tracer_flags.
333  */
334 struct tracer_opt {
335         const char      *name; /* Will appear on the trace_options file */
336         u32             bit; /* Mask assigned in val field in tracer_flags */
337 };
338
339 /*
340  * The set of specific options for a tracer. Your tracer
341  * have to set the initial value of the flags val.
342  */
343 struct tracer_flags {
344         u32                     val;
345         struct tracer_opt       *opts;
346 };
347
348 /* Makes more easy to define a tracer opt */
349 #define TRACER_OPT(s, b)        .name = #s, .bit = b
350
351
352 /**
353  * struct tracer - a specific tracer and its callbacks to interact with debugfs
354  * @name: the name chosen to select it on the available_tracers file
355  * @init: called when one switches to this tracer (echo name > current_tracer)
356  * @reset: called when one switches to another tracer
357  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
358  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
359  * @open: called when the trace file is opened
360  * @pipe_open: called when the trace_pipe file is opened
361  * @wait_pipe: override how the user waits for traces on trace_pipe
362  * @close: called when the trace file is released
363  * @read: override the default read callback on trace_pipe
364  * @splice_read: override the default splice_read callback on trace_pipe
365  * @selftest: selftest to run on boot (see trace_selftest.c)
366  * @print_headers: override the first lines that describe your columns
367  * @print_line: callback that prints a trace
368  * @set_flag: signals one of your private flags changed (trace_options file)
369  * @flags: your private flags
370  */
371 struct tracer {
372         const char              *name;
373         int                     (*init)(struct trace_array *tr);
374         void                    (*reset)(struct trace_array *tr);
375         void                    (*start)(struct trace_array *tr);
376         void                    (*stop)(struct trace_array *tr);
377         void                    (*open)(struct trace_iterator *iter);
378         void                    (*pipe_open)(struct trace_iterator *iter);
379         void                    (*wait_pipe)(struct trace_iterator *iter);
380         void                    (*close)(struct trace_iterator *iter);
381         ssize_t                 (*read)(struct trace_iterator *iter,
382                                         struct file *filp, char __user *ubuf,
383                                         size_t cnt, loff_t *ppos);
384         ssize_t                 (*splice_read)(struct trace_iterator *iter,
385                                                struct file *filp,
386                                                loff_t *ppos,
387                                                struct pipe_inode_info *pipe,
388                                                size_t len,
389                                                unsigned int flags);
390 #ifdef CONFIG_FTRACE_STARTUP_TEST
391         int                     (*selftest)(struct tracer *trace,
392                                             struct trace_array *tr);
393 #endif
394         void                    (*print_header)(struct seq_file *m);
395         enum print_line_t       (*print_line)(struct trace_iterator *iter);
396         /* If you handled the flag setting, return 0 */
397         int                     (*set_flag)(u32 old_flags, u32 bit, int set);
398         struct tracer           *next;
399         int                     print_max;
400         struct tracer_flags     *flags;
401         struct tracer_stat      *stats;
402 };
403
404
405 #define TRACE_PIPE_ALL_CPU      -1
406
407 int tracer_init(struct tracer *t, struct trace_array *tr);
408 int tracing_is_enabled(void);
409 void trace_wake_up(void);
410 void tracing_reset(struct trace_array *tr, int cpu);
411 void tracing_reset_online_cpus(struct trace_array *tr);
412 int tracing_open_generic(struct inode *inode, struct file *filp);
413 struct dentry *trace_create_file(const char *name,
414                                  mode_t mode,
415                                  struct dentry *parent,
416                                  void *data,
417                                  const struct file_operations *fops);
418
419 struct dentry *tracing_init_dentry(void);
420 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
421
422 struct ring_buffer_event;
423
424 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
425                                                     int type,
426                                                     unsigned long len,
427                                                     unsigned long flags,
428                                                     int pc);
429 void trace_buffer_unlock_commit(struct trace_array *tr,
430                                 struct ring_buffer_event *event,
431                                 unsigned long flags, int pc);
432
433 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
434                                                 struct trace_array_cpu *data);
435
436 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
437                                           int *ent_cpu, u64 *ent_ts);
438
439 void tracing_generic_entry_update(struct trace_entry *entry,
440                                   unsigned long flags,
441                                   int pc);
442
443 void default_wait_pipe(struct trace_iterator *iter);
444 void poll_wait_pipe(struct trace_iterator *iter);
445
446 void ftrace(struct trace_array *tr,
447                             struct trace_array_cpu *data,
448                             unsigned long ip,
449                             unsigned long parent_ip,
450                             unsigned long flags, int pc);
451 void tracing_sched_switch_trace(struct trace_array *tr,
452                                 struct task_struct *prev,
453                                 struct task_struct *next,
454                                 unsigned long flags, int pc);
455
456 void tracing_sched_wakeup_trace(struct trace_array *tr,
457                                 struct task_struct *wakee,
458                                 struct task_struct *cur,
459                                 unsigned long flags, int pc);
460 void trace_special(struct trace_array *tr,
461                    struct trace_array_cpu *data,
462                    unsigned long arg1,
463                    unsigned long arg2,
464                    unsigned long arg3, int pc);
465 void trace_function(struct trace_array *tr,
466                     unsigned long ip,
467                     unsigned long parent_ip,
468                     unsigned long flags, int pc);
469
470 void trace_graph_return(struct ftrace_graph_ret *trace);
471 int trace_graph_entry(struct ftrace_graph_ent *trace);
472
473 void tracing_start_cmdline_record(void);
474 void tracing_stop_cmdline_record(void);
475 void tracing_sched_switch_assign_trace(struct trace_array *tr);
476 void tracing_stop_sched_switch_record(void);
477 void tracing_start_sched_switch_record(void);
478 int register_tracer(struct tracer *type);
479 void unregister_tracer(struct tracer *type);
480
481 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
482
483 extern unsigned long tracing_max_latency;
484 extern unsigned long tracing_thresh;
485
486 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
487 void update_max_tr_single(struct trace_array *tr,
488                           struct task_struct *tsk, int cpu);
489
490 void __trace_stack(struct trace_array *tr,
491                    unsigned long flags,
492                    int skip, int pc);
493
494 extern cycle_t ftrace_now(int cpu);
495
496 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
497 typedef void
498 (*tracer_switch_func_t)(void *private,
499                         void *__rq,
500                         struct task_struct *prev,
501                         struct task_struct *next);
502
503 struct tracer_switch_ops {
504         tracer_switch_func_t            func;
505         void                            *private;
506         struct tracer_switch_ops        *next;
507 };
508 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
509
510 extern void trace_find_cmdline(int pid, char comm[]);
511
512 #ifdef CONFIG_DYNAMIC_FTRACE
513 extern unsigned long ftrace_update_tot_cnt;
514 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
515 extern int DYN_FTRACE_TEST_NAME(void);
516 #endif
517
518 #ifdef CONFIG_FTRACE_STARTUP_TEST
519 extern int trace_selftest_startup_function(struct tracer *trace,
520                                            struct trace_array *tr);
521 extern int trace_selftest_startup_function_graph(struct tracer *trace,
522                                                  struct trace_array *tr);
523 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
524                                           struct trace_array *tr);
525 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
526                                              struct trace_array *tr);
527 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
528                                                  struct trace_array *tr);
529 extern int trace_selftest_startup_wakeup(struct tracer *trace,
530                                          struct trace_array *tr);
531 extern int trace_selftest_startup_nop(struct tracer *trace,
532                                          struct trace_array *tr);
533 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
534                                                struct trace_array *tr);
535 extern int trace_selftest_startup_sysprof(struct tracer *trace,
536                                                struct trace_array *tr);
537 extern int trace_selftest_startup_branch(struct tracer *trace,
538                                          struct trace_array *tr);
539 #endif /* CONFIG_FTRACE_STARTUP_TEST */
540
541 extern void *head_page(struct trace_array_cpu *data);
542 extern unsigned long long ns2usecs(cycle_t nsec);
543 extern int
544 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
545 extern int
546 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
547
548 extern unsigned long trace_flags;
549
550 /* Standard output formatting function used for function return traces */
551 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
552 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
553 extern enum print_line_t
554 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
555
556 #ifdef CONFIG_DYNAMIC_FTRACE
557 /* TODO: make this variable */
558 #define FTRACE_GRAPH_MAX_FUNCS          32
559 extern int ftrace_graph_count;
560 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
561
562 static inline int ftrace_graph_addr(unsigned long addr)
563 {
564         int i;
565
566         if (!ftrace_graph_count || test_tsk_trace_graph(current))
567                 return 1;
568
569         for (i = 0; i < ftrace_graph_count; i++) {
570                 if (addr == ftrace_graph_funcs[i])
571                         return 1;
572         }
573
574         return 0;
575 }
576 #else
577 static inline int ftrace_trace_addr(unsigned long addr)
578 {
579         return 1;
580 }
581 static inline int ftrace_graph_addr(unsigned long addr)
582 {
583         return 1;
584 }
585 #endif /* CONFIG_DYNAMIC_FTRACE */
586 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
587 static inline enum print_line_t
588 print_graph_function(struct trace_iterator *iter)
589 {
590         return TRACE_TYPE_UNHANDLED;
591 }
592 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
593
594 extern struct pid *ftrace_pid_trace;
595
596 static inline int ftrace_trace_task(struct task_struct *task)
597 {
598         if (!ftrace_pid_trace)
599                 return 1;
600
601         return test_tsk_trace_trace(task);
602 }
603
604 /*
605  * trace_iterator_flags is an enumeration that defines bit
606  * positions into trace_flags that controls the output.
607  *
608  * NOTE: These bits must match the trace_options array in
609  *       trace.c.
610  */
611 enum trace_iterator_flags {
612         TRACE_ITER_PRINT_PARENT         = 0x01,
613         TRACE_ITER_SYM_OFFSET           = 0x02,
614         TRACE_ITER_SYM_ADDR             = 0x04,
615         TRACE_ITER_VERBOSE              = 0x08,
616         TRACE_ITER_RAW                  = 0x10,
617         TRACE_ITER_HEX                  = 0x20,
618         TRACE_ITER_BIN                  = 0x40,
619         TRACE_ITER_BLOCK                = 0x80,
620         TRACE_ITER_STACKTRACE           = 0x100,
621         TRACE_ITER_SCHED_TREE           = 0x200,
622         TRACE_ITER_PRINTK               = 0x400,
623         TRACE_ITER_PREEMPTONLY          = 0x800,
624         TRACE_ITER_BRANCH               = 0x1000,
625         TRACE_ITER_ANNOTATE             = 0x2000,
626         TRACE_ITER_USERSTACKTRACE       = 0x4000,
627         TRACE_ITER_SYM_USEROBJ          = 0x8000,
628         TRACE_ITER_PRINTK_MSGONLY       = 0x10000,
629         TRACE_ITER_CONTEXT_INFO         = 0x20000, /* Print pid/cpu/time */
630         TRACE_ITER_LATENCY_FMT          = 0x40000,
631         TRACE_ITER_GLOBAL_CLK           = 0x80000,
632         TRACE_ITER_SLEEP_TIME           = 0x100000,
633         TRACE_ITER_GRAPH_TIME           = 0x200000,
634 };
635
636 /*
637  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
638  * control the output of kernel symbols.
639  */
640 #define TRACE_ITER_SYM_MASK \
641         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
642
643 extern struct tracer nop_trace;
644
645 /**
646  * ftrace_preempt_disable - disable preemption scheduler safe
647  *
648  * When tracing can happen inside the scheduler, there exists
649  * cases that the tracing might happen before the need_resched
650  * flag is checked. If this happens and the tracer calls
651  * preempt_enable (after a disable), a schedule might take place
652  * causing an infinite recursion.
653  *
654  * To prevent this, we read the need_resched flag before
655  * disabling preemption. When we want to enable preemption we
656  * check the flag, if it is set, then we call preempt_enable_no_resched.
657  * Otherwise, we call preempt_enable.
658  *
659  * The rational for doing the above is that if need_resched is set
660  * and we have yet to reschedule, we are either in an atomic location
661  * (where we do not need to check for scheduling) or we are inside
662  * the scheduler and do not want to resched.
663  */
664 static inline int ftrace_preempt_disable(void)
665 {
666         int resched;
667
668         resched = need_resched();
669         preempt_disable_notrace();
670
671         return resched;
672 }
673
674 /**
675  * ftrace_preempt_enable - enable preemption scheduler safe
676  * @resched: the return value from ftrace_preempt_disable
677  *
678  * This is a scheduler safe way to enable preemption and not miss
679  * any preemption checks. The disabled saved the state of preemption.
680  * If resched is set, then we are either inside an atomic or
681  * are inside the scheduler (we would have already scheduled
682  * otherwise). In this case, we do not want to call normal
683  * preempt_enable, but preempt_enable_no_resched instead.
684  */
685 static inline void ftrace_preempt_enable(int resched)
686 {
687         if (resched)
688                 preempt_enable_no_resched_notrace();
689         else
690                 preempt_enable_notrace();
691 }
692
693 #ifdef CONFIG_BRANCH_TRACER
694 extern int enable_branch_tracing(struct trace_array *tr);
695 extern void disable_branch_tracing(void);
696 static inline int trace_branch_enable(struct trace_array *tr)
697 {
698         if (trace_flags & TRACE_ITER_BRANCH)
699                 return enable_branch_tracing(tr);
700         return 0;
701 }
702 static inline void trace_branch_disable(void)
703 {
704         /* due to races, always disable */
705         disable_branch_tracing();
706 }
707 #else
708 static inline int trace_branch_enable(struct trace_array *tr)
709 {
710         return 0;
711 }
712 static inline void trace_branch_disable(void)
713 {
714 }
715 #endif /* CONFIG_BRANCH_TRACER */
716
717 /* set ring buffers to default size if not already done so */
718 int tracing_update_buffers(void);
719
720 /* trace event type bit fields, not numeric */
721 enum {
722         TRACE_EVENT_TYPE_PRINTF         = 1,
723         TRACE_EVENT_TYPE_RAW            = 2,
724 };
725
726 struct ftrace_event_field {
727         struct list_head        link;
728         char                    *name;
729         char                    *type;
730         int                     offset;
731         int                     size;
732 };
733
734 struct event_filter {
735         int                     n_preds;
736         struct filter_pred      **preds;
737 };
738
739 struct event_subsystem {
740         struct list_head        list;
741         const char              *name;
742         struct dentry           *entry;
743         void                    *filter;
744 };
745
746 struct filter_pred;
747
748 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event);
749
750 struct filter_pred {
751         filter_pred_fn_t fn;
752         u64 val;
753         char str_val[MAX_FILTER_STR_VAL];
754         int str_len;
755         char *field_name;
756         int offset;
757         int not;
758         int or;
759         int compound;
760         int clear;
761 };
762
763 extern void filter_free_pred(struct filter_pred *pred);
764 extern void filter_print_preds(struct ftrace_event_call *call,
765                                struct trace_seq *s);
766 extern int filter_parse(char **pbuf, struct filter_pred *pred);
767 extern int filter_add_pred(struct ftrace_event_call *call,
768                            struct filter_pred *pred);
769 extern void filter_disable_preds(struct ftrace_event_call *call);
770 extern void filter_free_subsystem_preds(struct event_subsystem *system);
771 extern void filter_print_subsystem_preds(struct event_subsystem *system,
772                                          struct trace_seq *s);
773 extern int filter_add_subsystem_pred(struct event_subsystem *system,
774                                      struct filter_pred *pred);
775
776 static inline int
777 filter_check_discard(struct ftrace_event_call *call, void *rec,
778                      struct ring_buffer *buffer,
779                      struct ring_buffer_event *event)
780 {
781         if (unlikely(call->filter_active) && !filter_match_preds(call, rec)) {
782                 ring_buffer_discard_commit(buffer, event);
783                 return 1;
784         }
785
786         return 0;
787 }
788
789 extern struct list_head ftrace_events;
790
791 extern const char *__start___trace_bprintk_fmt[];
792 extern const char *__stop___trace_bprintk_fmt[];
793
794 #undef TRACE_EVENT_FORMAT
795 #define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt)      \
796         extern struct ftrace_event_call event_##call;
797 #undef TRACE_EVENT_FORMAT_NOFILTER
798 #define TRACE_EVENT_FORMAT_NOFILTER(call, proto, args, fmt, tstruct, tpfmt)
799 #include "trace_event_types.h"
800
801 #endif /* _LINUX_KERNEL_TRACE_H */