Merge branch 'x86/asm' into tracing/syscalls
[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 <trace/kmemtrace.h>
13 #include <trace/power.h>
14
15 enum trace_type {
16         __TRACE_FIRST_TYPE = 0,
17
18         TRACE_FN,
19         TRACE_CTX,
20         TRACE_WAKE,
21         TRACE_STACK,
22         TRACE_PRINT,
23         TRACE_SPECIAL,
24         TRACE_MMIO_RW,
25         TRACE_MMIO_MAP,
26         TRACE_BRANCH,
27         TRACE_BOOT_CALL,
28         TRACE_BOOT_RET,
29         TRACE_GRAPH_RET,
30         TRACE_GRAPH_ENT,
31         TRACE_USER_STACK,
32         TRACE_HW_BRANCHES,
33         TRACE_SYSCALL_ENTER,
34         TRACE_SYSCALL_EXIT,
35         TRACE_KMEM_ALLOC,
36         TRACE_KMEM_FREE,
37         TRACE_POWER,
38         TRACE_BLK,
39
40         __TRACE_LAST_TYPE,
41 };
42
43 /*
44  * The trace entry - the most basic unit of tracing. This is what
45  * is printed in the end as a single line in the trace output, such as:
46  *
47  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
48  */
49 struct trace_entry {
50         unsigned char           type;
51         unsigned char           flags;
52         unsigned char           preempt_count;
53         int                     pid;
54         int                     tgid;
55 };
56
57 /*
58  * Function trace entry - function address and parent function addres:
59  */
60 struct ftrace_entry {
61         struct trace_entry      ent;
62         unsigned long           ip;
63         unsigned long           parent_ip;
64 };
65
66 /* Function call entry */
67 struct ftrace_graph_ent_entry {
68         struct trace_entry              ent;
69         struct ftrace_graph_ent         graph_ent;
70 };
71
72 /* Function return entry */
73 struct ftrace_graph_ret_entry {
74         struct trace_entry              ent;
75         struct ftrace_graph_ret         ret;
76 };
77 extern struct tracer boot_tracer;
78
79 /*
80  * Context switch trace entry - which task (and prio) we switched from/to:
81  */
82 struct ctx_switch_entry {
83         struct trace_entry      ent;
84         unsigned int            prev_pid;
85         unsigned char           prev_prio;
86         unsigned char           prev_state;
87         unsigned int            next_pid;
88         unsigned char           next_prio;
89         unsigned char           next_state;
90         unsigned int            next_cpu;
91 };
92
93 /*
94  * Special (free-form) trace entry:
95  */
96 struct special_entry {
97         struct trace_entry      ent;
98         unsigned long           arg1;
99         unsigned long           arg2;
100         unsigned long           arg3;
101 };
102
103 /*
104  * Stack-trace entry:
105  */
106
107 #define FTRACE_STACK_ENTRIES    8
108
109 struct stack_entry {
110         struct trace_entry      ent;
111         unsigned long           caller[FTRACE_STACK_ENTRIES];
112 };
113
114 struct userstack_entry {
115         struct trace_entry      ent;
116         unsigned long           caller[FTRACE_STACK_ENTRIES];
117 };
118
119 /*
120  * trace_printk entry:
121  */
122 struct print_entry {
123         struct trace_entry      ent;
124         unsigned long           ip;
125         int                     depth;
126         const char              *fmt;
127         u32                     buf[];
128 };
129
130 #define TRACE_OLD_SIZE          88
131
132 struct trace_field_cont {
133         unsigned char           type;
134         /* Temporary till we get rid of this completely */
135         char                    buf[TRACE_OLD_SIZE - 1];
136 };
137
138 struct trace_mmiotrace_rw {
139         struct trace_entry      ent;
140         struct mmiotrace_rw     rw;
141 };
142
143 struct trace_mmiotrace_map {
144         struct trace_entry      ent;
145         struct mmiotrace_map    map;
146 };
147
148 struct trace_boot_call {
149         struct trace_entry      ent;
150         struct boot_trace_call boot_call;
151 };
152
153 struct trace_boot_ret {
154         struct trace_entry      ent;
155         struct boot_trace_ret boot_ret;
156 };
157
158 #define TRACE_FUNC_SIZE 30
159 #define TRACE_FILE_SIZE 20
160 struct trace_branch {
161         struct trace_entry      ent;
162         unsigned                line;
163         char                    func[TRACE_FUNC_SIZE+1];
164         char                    file[TRACE_FILE_SIZE+1];
165         char                    correct;
166 };
167
168 struct hw_branch_entry {
169         struct trace_entry      ent;
170         u64                     from;
171         u64                     to;
172 };
173
174 struct trace_power {
175         struct trace_entry      ent;
176         struct power_trace      state_data;
177 };
178
179 struct kmemtrace_alloc_entry {
180         struct trace_entry      ent;
181         enum kmemtrace_type_id type_id;
182         unsigned long call_site;
183         const void *ptr;
184         size_t bytes_req;
185         size_t bytes_alloc;
186         gfp_t gfp_flags;
187         int node;
188 };
189
190 struct kmemtrace_free_entry {
191         struct trace_entry      ent;
192         enum kmemtrace_type_id type_id;
193         unsigned long call_site;
194         const void *ptr;
195 };
196
197 struct syscall_trace_enter {
198         struct trace_entry      ent;
199         int                     nr;
200         unsigned long           args[];
201 };
202
203 struct syscall_trace_exit {
204         struct trace_entry      ent;
205         int                     nr;
206         unsigned long           ret;
207 };
208
209
210 /*
211  * trace_flag_type is an enumeration that holds different
212  * states when a trace occurs. These are:
213  *  IRQS_OFF            - interrupts were disabled
214  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
215  *  NEED_RESCED         - reschedule is requested
216  *  HARDIRQ             - inside an interrupt handler
217  *  SOFTIRQ             - inside a softirq handler
218  */
219 enum trace_flag_type {
220         TRACE_FLAG_IRQS_OFF             = 0x01,
221         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
222         TRACE_FLAG_NEED_RESCHED         = 0x04,
223         TRACE_FLAG_HARDIRQ              = 0x08,
224         TRACE_FLAG_SOFTIRQ              = 0x10,
225 };
226
227 #define TRACE_BUF_SIZE          1024
228
229 /*
230  * The CPU trace array - it consists of thousands of trace entries
231  * plus some other descriptor data: (for example which task started
232  * the trace, etc.)
233  */
234 struct trace_array_cpu {
235         atomic_t                disabled;
236         void                    *buffer_page;   /* ring buffer spare */
237
238         /* these fields get copied into max-trace: */
239         unsigned long           trace_idx;
240         unsigned long           overrun;
241         unsigned long           saved_latency;
242         unsigned long           critical_start;
243         unsigned long           critical_end;
244         unsigned long           critical_sequence;
245         unsigned long           nice;
246         unsigned long           policy;
247         unsigned long           rt_priority;
248         cycle_t                 preempt_timestamp;
249         pid_t                   pid;
250         uid_t                   uid;
251         char                    comm[TASK_COMM_LEN];
252 };
253
254 struct trace_iterator;
255
256 /*
257  * The trace array - an array of per-CPU trace arrays. This is the
258  * highest level data structure that individual tracers deal with.
259  * They have on/off state as well:
260  */
261 struct trace_array {
262         struct ring_buffer      *buffer;
263         unsigned long           entries;
264         int                     cpu;
265         cycle_t                 time_start;
266         struct task_struct      *waiter;
267         struct trace_array_cpu  *data[NR_CPUS];
268 };
269
270 #define FTRACE_CMP_TYPE(var, type) \
271         __builtin_types_compatible_p(typeof(var), type *)
272
273 #undef IF_ASSIGN
274 #define IF_ASSIGN(var, entry, etype, id)                \
275         if (FTRACE_CMP_TYPE(var, etype)) {              \
276                 var = (typeof(var))(entry);             \
277                 WARN_ON(id && (entry)->type != id);     \
278                 break;                                  \
279         }
280
281 /* Will cause compile errors if type is not found. */
282 extern void __ftrace_bad_type(void);
283
284 /*
285  * The trace_assign_type is a verifier that the entry type is
286  * the same as the type being assigned. To add new types simply
287  * add a line with the following format:
288  *
289  * IF_ASSIGN(var, ent, type, id);
290  *
291  *  Where "type" is the trace type that includes the trace_entry
292  *  as the "ent" item. And "id" is the trace identifier that is
293  *  used in the trace_type enum.
294  *
295  *  If the type can have more than one id, then use zero.
296  */
297 #define trace_assign_type(var, ent)                                     \
298         do {                                                            \
299                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
300                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
301                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
302                 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
303                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
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 /* Return values for print_line callback */
330 enum print_line_t {
331         TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
332         TRACE_TYPE_HANDLED      = 1,
333         TRACE_TYPE_UNHANDLED    = 2,    /* Relay to other output functions */
334         TRACE_TYPE_NO_CONSUME   = 3     /* Handled but ask to not consume */
335 };
336
337
338 /*
339  * An option specific to a tracer. This is a boolean value.
340  * The bit is the bit index that sets its value on the
341  * flags value in struct tracer_flags.
342  */
343 struct tracer_opt {
344         const char      *name; /* Will appear on the trace_options file */
345         u32             bit; /* Mask assigned in val field in tracer_flags */
346 };
347
348 /*
349  * The set of specific options for a tracer. Your tracer
350  * have to set the initial value of the flags val.
351  */
352 struct tracer_flags {
353         u32                     val;
354         struct tracer_opt       *opts;
355 };
356
357 /* Makes more easy to define a tracer opt */
358 #define TRACER_OPT(s, b)        .name = #s, .bit = b
359
360
361 /**
362  * struct tracer - a specific tracer and its callbacks to interact with debugfs
363  * @name: the name chosen to select it on the available_tracers file
364  * @init: called when one switches to this tracer (echo name > current_tracer)
365  * @reset: called when one switches to another tracer
366  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
367  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
368  * @open: called when the trace file is opened
369  * @pipe_open: called when the trace_pipe file is opened
370  * @wait_pipe: override how the user waits for traces on trace_pipe
371  * @close: called when the trace file is released
372  * @read: override the default read callback on trace_pipe
373  * @splice_read: override the default splice_read callback on trace_pipe
374  * @selftest: selftest to run on boot (see trace_selftest.c)
375  * @print_headers: override the first lines that describe your columns
376  * @print_line: callback that prints a trace
377  * @set_flag: signals one of your private flags changed (trace_options file)
378  * @flags: your private flags
379  */
380 struct tracer {
381         const char              *name;
382         int                     (*init)(struct trace_array *tr);
383         void                    (*reset)(struct trace_array *tr);
384         void                    (*start)(struct trace_array *tr);
385         void                    (*stop)(struct trace_array *tr);
386         void                    (*open)(struct trace_iterator *iter);
387         void                    (*pipe_open)(struct trace_iterator *iter);
388         void                    (*wait_pipe)(struct trace_iterator *iter);
389         void                    (*close)(struct trace_iterator *iter);
390         ssize_t                 (*read)(struct trace_iterator *iter,
391                                         struct file *filp, char __user *ubuf,
392                                         size_t cnt, loff_t *ppos);
393         ssize_t                 (*splice_read)(struct trace_iterator *iter,
394                                                struct file *filp,
395                                                loff_t *ppos,
396                                                struct pipe_inode_info *pipe,
397                                                size_t len,
398                                                unsigned int flags);
399 #ifdef CONFIG_FTRACE_STARTUP_TEST
400         int                     (*selftest)(struct tracer *trace,
401                                             struct trace_array *tr);
402 #endif
403         void                    (*print_header)(struct seq_file *m);
404         enum print_line_t       (*print_line)(struct trace_iterator *iter);
405         /* If you handled the flag setting, return 0 */
406         int                     (*set_flag)(u32 old_flags, u32 bit, int set);
407         struct tracer           *next;
408         int                     print_max;
409         struct tracer_flags     *flags;
410         struct tracer_stat      *stats;
411 };
412
413 struct trace_seq {
414         unsigned char           buffer[PAGE_SIZE];
415         unsigned int            len;
416         unsigned int            readpos;
417 };
418
419 static inline void
420 trace_seq_init(struct trace_seq *s)
421 {
422         s->len = 0;
423         s->readpos = 0;
424 }
425
426
427 #define TRACE_PIPE_ALL_CPU      -1
428
429 /*
430  * Trace iterator - used by printout routines who present trace
431  * results to users and which routines might sleep, etc:
432  */
433 struct trace_iterator {
434         struct trace_array      *tr;
435         struct tracer           *trace;
436         void                    *private;
437         int                     cpu_file;
438         struct mutex            mutex;
439         struct ring_buffer_iter *buffer_iter[NR_CPUS];
440
441         /* The below is zeroed out in pipe_read */
442         struct trace_seq        seq;
443         struct trace_entry      *ent;
444         int                     cpu;
445         u64                     ts;
446
447         unsigned long           iter_flags;
448         loff_t                  pos;
449         long                    idx;
450
451         cpumask_var_t           started;
452 };
453
454 int tracer_init(struct tracer *t, struct trace_array *tr);
455 int tracing_is_enabled(void);
456 void trace_wake_up(void);
457 void tracing_reset(struct trace_array *tr, int cpu);
458 void tracing_reset_online_cpus(struct trace_array *tr);
459 int tracing_open_generic(struct inode *inode, struct file *filp);
460 struct dentry *tracing_init_dentry(void);
461 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
462
463 struct ring_buffer_event;
464
465 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
466                                                     unsigned char type,
467                                                     unsigned long len,
468                                                     unsigned long flags,
469                                                     int pc);
470 void trace_buffer_unlock_commit(struct trace_array *tr,
471                                 struct ring_buffer_event *event,
472                                 unsigned long flags, int pc);
473
474 struct ring_buffer_event *
475 trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
476                                   unsigned long flags, int pc);
477 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
478                                         unsigned long flags, int pc);
479
480 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
481                                                 struct trace_array_cpu *data);
482
483 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
484                                           int *ent_cpu, u64 *ent_ts);
485
486 void tracing_generic_entry_update(struct trace_entry *entry,
487                                   unsigned long flags,
488                                   int pc);
489
490 void default_wait_pipe(struct trace_iterator *iter);
491 void poll_wait_pipe(struct trace_iterator *iter);
492
493 void ftrace(struct trace_array *tr,
494                             struct trace_array_cpu *data,
495                             unsigned long ip,
496                             unsigned long parent_ip,
497                             unsigned long flags, int pc);
498 void tracing_sched_switch_trace(struct trace_array *tr,
499                                 struct task_struct *prev,
500                                 struct task_struct *next,
501                                 unsigned long flags, int pc);
502 void tracing_record_cmdline(struct task_struct *tsk);
503
504 void tracing_sched_wakeup_trace(struct trace_array *tr,
505                                 struct task_struct *wakee,
506                                 struct task_struct *cur,
507                                 unsigned long flags, int pc);
508 void trace_special(struct trace_array *tr,
509                    struct trace_array_cpu *data,
510                    unsigned long arg1,
511                    unsigned long arg2,
512                    unsigned long arg3, int pc);
513 void trace_function(struct trace_array *tr,
514                     unsigned long ip,
515                     unsigned long parent_ip,
516                     unsigned long flags, int pc);
517
518 void trace_graph_return(struct ftrace_graph_ret *trace);
519 int trace_graph_entry(struct ftrace_graph_ent *trace);
520
521 void tracing_start_cmdline_record(void);
522 void tracing_stop_cmdline_record(void);
523 void tracing_sched_switch_assign_trace(struct trace_array *tr);
524 void tracing_stop_sched_switch_record(void);
525 void tracing_start_sched_switch_record(void);
526 int register_tracer(struct tracer *type);
527 void unregister_tracer(struct tracer *type);
528
529 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
530
531 extern unsigned long tracing_max_latency;
532 extern unsigned long tracing_thresh;
533
534 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
535 void update_max_tr_single(struct trace_array *tr,
536                           struct task_struct *tsk, int cpu);
537
538 void __trace_stack(struct trace_array *tr,
539                    unsigned long flags,
540                    int skip, int pc);
541
542 extern cycle_t ftrace_now(int cpu);
543
544 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
545 typedef void
546 (*tracer_switch_func_t)(void *private,
547                         void *__rq,
548                         struct task_struct *prev,
549                         struct task_struct *next);
550
551 struct tracer_switch_ops {
552         tracer_switch_func_t            func;
553         void                            *private;
554         struct tracer_switch_ops        *next;
555 };
556 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
557
558 extern char *trace_find_cmdline(int pid);
559
560 #ifdef CONFIG_DYNAMIC_FTRACE
561 extern unsigned long ftrace_update_tot_cnt;
562 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
563 extern int DYN_FTRACE_TEST_NAME(void);
564 #endif
565
566 #ifdef CONFIG_FTRACE_STARTUP_TEST
567 extern int trace_selftest_startup_function(struct tracer *trace,
568                                            struct trace_array *tr);
569 extern int trace_selftest_startup_function_graph(struct tracer *trace,
570                                                  struct trace_array *tr);
571 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
572                                           struct trace_array *tr);
573 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
574                                              struct trace_array *tr);
575 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
576                                                  struct trace_array *tr);
577 extern int trace_selftest_startup_wakeup(struct tracer *trace,
578                                          struct trace_array *tr);
579 extern int trace_selftest_startup_nop(struct tracer *trace,
580                                          struct trace_array *tr);
581 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
582                                                struct trace_array *tr);
583 extern int trace_selftest_startup_sysprof(struct tracer *trace,
584                                                struct trace_array *tr);
585 extern int trace_selftest_startup_branch(struct tracer *trace,
586                                          struct trace_array *tr);
587 #endif /* CONFIG_FTRACE_STARTUP_TEST */
588
589 extern void *head_page(struct trace_array_cpu *data);
590 extern long ns2usecs(cycle_t nsec);
591 extern int
592 trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args);
593
594 extern unsigned long trace_flags;
595
596 /* Standard output formatting function used for function return traces */
597 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
598 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
599
600 #ifdef CONFIG_DYNAMIC_FTRACE
601 /* TODO: make this variable */
602 #define FTRACE_GRAPH_MAX_FUNCS          32
603 extern int ftrace_graph_count;
604 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
605
606 static inline int ftrace_graph_addr(unsigned long addr)
607 {
608         int i;
609
610         if (!ftrace_graph_count || test_tsk_trace_graph(current))
611                 return 1;
612
613         for (i = 0; i < ftrace_graph_count; i++) {
614                 if (addr == ftrace_graph_funcs[i])
615                         return 1;
616         }
617
618         return 0;
619 }
620 #else
621 static inline int ftrace_trace_addr(unsigned long addr)
622 {
623         return 1;
624 }
625 static inline int ftrace_graph_addr(unsigned long addr)
626 {
627         return 1;
628 }
629 #endif /* CONFIG_DYNAMIC_FTRACE */
630
631 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
632 static inline enum print_line_t
633 print_graph_function(struct trace_iterator *iter)
634 {
635         return TRACE_TYPE_UNHANDLED;
636 }
637 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
638
639 extern struct pid *ftrace_pid_trace;
640
641 static inline int ftrace_trace_task(struct task_struct *task)
642 {
643         if (!ftrace_pid_trace)
644                 return 1;
645
646         return test_tsk_trace_trace(task);
647 }
648
649 /*
650  * trace_iterator_flags is an enumeration that defines bit
651  * positions into trace_flags that controls the output.
652  *
653  * NOTE: These bits must match the trace_options array in
654  *       trace.c.
655  */
656 enum trace_iterator_flags {
657         TRACE_ITER_PRINT_PARENT         = 0x01,
658         TRACE_ITER_SYM_OFFSET           = 0x02,
659         TRACE_ITER_SYM_ADDR             = 0x04,
660         TRACE_ITER_VERBOSE              = 0x08,
661         TRACE_ITER_RAW                  = 0x10,
662         TRACE_ITER_HEX                  = 0x20,
663         TRACE_ITER_BIN                  = 0x40,
664         TRACE_ITER_BLOCK                = 0x80,
665         TRACE_ITER_STACKTRACE           = 0x100,
666         TRACE_ITER_SCHED_TREE           = 0x200,
667         TRACE_ITER_PRINTK               = 0x400,
668         TRACE_ITER_PREEMPTONLY          = 0x800,
669         TRACE_ITER_BRANCH               = 0x1000,
670         TRACE_ITER_ANNOTATE             = 0x2000,
671         TRACE_ITER_USERSTACKTRACE       = 0x4000,
672         TRACE_ITER_SYM_USEROBJ          = 0x8000,
673         TRACE_ITER_PRINTK_MSGONLY       = 0x10000,
674         TRACE_ITER_CONTEXT_INFO         = 0x20000, /* Print pid/cpu/time */
675         TRACE_ITER_LATENCY_FMT          = 0x40000,
676 };
677
678 /*
679  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
680  * control the output of kernel symbols.
681  */
682 #define TRACE_ITER_SYM_MASK \
683         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
684
685 extern struct tracer nop_trace;
686
687 /**
688  * ftrace_preempt_disable - disable preemption scheduler safe
689  *
690  * When tracing can happen inside the scheduler, there exists
691  * cases that the tracing might happen before the need_resched
692  * flag is checked. If this happens and the tracer calls
693  * preempt_enable (after a disable), a schedule might take place
694  * causing an infinite recursion.
695  *
696  * To prevent this, we read the need_resched flag before
697  * disabling preemption. When we want to enable preemption we
698  * check the flag, if it is set, then we call preempt_enable_no_resched.
699  * Otherwise, we call preempt_enable.
700  *
701  * The rational for doing the above is that if need_resched is set
702  * and we have yet to reschedule, we are either in an atomic location
703  * (where we do not need to check for scheduling) or we are inside
704  * the scheduler and do not want to resched.
705  */
706 static inline int ftrace_preempt_disable(void)
707 {
708         int resched;
709
710         resched = need_resched();
711         preempt_disable_notrace();
712
713         return resched;
714 }
715
716 /**
717  * ftrace_preempt_enable - enable preemption scheduler safe
718  * @resched: the return value from ftrace_preempt_disable
719  *
720  * This is a scheduler safe way to enable preemption and not miss
721  * any preemption checks. The disabled saved the state of preemption.
722  * If resched is set, then we are either inside an atomic or
723  * are inside the scheduler (we would have already scheduled
724  * otherwise). In this case, we do not want to call normal
725  * preempt_enable, but preempt_enable_no_resched instead.
726  */
727 static inline void ftrace_preempt_enable(int resched)
728 {
729         if (resched)
730                 preempt_enable_no_resched_notrace();
731         else
732                 preempt_enable_notrace();
733 }
734
735 #ifdef CONFIG_BRANCH_TRACER
736 extern int enable_branch_tracing(struct trace_array *tr);
737 extern void disable_branch_tracing(void);
738 static inline int trace_branch_enable(struct trace_array *tr)
739 {
740         if (trace_flags & TRACE_ITER_BRANCH)
741                 return enable_branch_tracing(tr);
742         return 0;
743 }
744 static inline void trace_branch_disable(void)
745 {
746         /* due to races, always disable */
747         disable_branch_tracing();
748 }
749 #else
750 static inline int trace_branch_enable(struct trace_array *tr)
751 {
752         return 0;
753 }
754 static inline void trace_branch_disable(void)
755 {
756 }
757 #endif /* CONFIG_BRANCH_TRACER */
758
759 /* trace event type bit fields, not numeric */
760 enum {
761         TRACE_EVENT_TYPE_PRINTF         = 1,
762         TRACE_EVENT_TYPE_RAW            = 2,
763 };
764
765 struct ftrace_event_call {
766         char            *name;
767         char            *system;
768         struct dentry   *dir;
769         int             enabled;
770         int             (*regfunc)(void);
771         void            (*unregfunc)(void);
772         int             id;
773         int             (*raw_init)(void);
774         int             (*show_format)(struct trace_seq *s);
775 };
776
777 void event_trace_printk(unsigned long ip, const char *fmt, ...);
778 extern struct ftrace_event_call __start_ftrace_events[];
779 extern struct ftrace_event_call __stop_ftrace_events[];
780
781 #endif /* _LINUX_KERNEL_TRACE_H */