trace/syscalls: Change ret param in struct syscall_trace_exit to long
[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/tracepoint.h>
11 #include <linux/ftrace.h>
12 #include <trace/boot.h>
13 #include <linux/kmemtrace.h>
14 #include <linux/hw_breakpoint.h>
15
16 #include <linux/trace_seq.h>
17 #include <linux/ftrace_event.h>
18
19 enum trace_type {
20         __TRACE_FIRST_TYPE = 0,
21
22         TRACE_FN,
23         TRACE_CTX,
24         TRACE_WAKE,
25         TRACE_STACK,
26         TRACE_PRINT,
27         TRACE_BPRINT,
28         TRACE_SPECIAL,
29         TRACE_MMIO_RW,
30         TRACE_MMIO_MAP,
31         TRACE_BRANCH,
32         TRACE_BOOT_CALL,
33         TRACE_BOOT_RET,
34         TRACE_GRAPH_RET,
35         TRACE_GRAPH_ENT,
36         TRACE_USER_STACK,
37         TRACE_HW_BRANCHES,
38         TRACE_KMEM_ALLOC,
39         TRACE_KMEM_FREE,
40         TRACE_BLK,
41         TRACE_KSYM,
42
43         __TRACE_LAST_TYPE,
44 };
45
46 enum kmemtrace_type_id {
47         KMEMTRACE_TYPE_KMALLOC = 0,     /* kmalloc() or kfree(). */
48         KMEMTRACE_TYPE_CACHE,           /* kmem_cache_*(). */
49         KMEMTRACE_TYPE_PAGES,           /* __get_free_pages() and friends. */
50 };
51
52 extern struct tracer boot_tracer;
53
54 #undef __field
55 #define __field(type, item)             type    item;
56
57 #undef __field_struct
58 #define __field_struct(type, item)      __field(type, item)
59
60 #undef __field_desc
61 #define __field_desc(type, container, item)
62
63 #undef __array
64 #define __array(type, item, size)       type    item[size];
65
66 #undef __array_desc
67 #define __array_desc(type, container, item, size)
68
69 #undef __dynamic_array
70 #define __dynamic_array(type, item)     type    item[];
71
72 #undef F_STRUCT
73 #define F_STRUCT(args...)               args
74
75 #undef FTRACE_ENTRY
76 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)     \
77         struct struct_name {                                    \
78                 struct trace_entry      ent;                    \
79                 tstruct                                         \
80         }
81
82 #undef TP_ARGS
83 #define TP_ARGS(args...)        args
84
85 #undef FTRACE_ENTRY_DUP
86 #define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)
87
88 #include "trace_entries.h"
89
90 /*
91  * syscalls are special, and need special handling, this is why
92  * they are not included in trace_entries.h
93  */
94 struct syscall_trace_enter {
95         struct trace_entry      ent;
96         int                     nr;
97         unsigned long           args[];
98 };
99
100 struct syscall_trace_exit {
101         struct trace_entry      ent;
102         int                     nr;
103         long                    ret;
104 };
105
106 struct kprobe_trace_entry {
107         struct trace_entry      ent;
108         unsigned long           ip;
109         int                     nargs;
110         unsigned long           args[];
111 };
112
113 #define SIZEOF_KPROBE_TRACE_ENTRY(n)                    \
114         (offsetof(struct kprobe_trace_entry, args) +    \
115         (sizeof(unsigned long) * (n)))
116
117 struct kretprobe_trace_entry {
118         struct trace_entry      ent;
119         unsigned long           func;
120         unsigned long           ret_ip;
121         int                     nargs;
122         unsigned long           args[];
123 };
124
125 #define SIZEOF_KRETPROBE_TRACE_ENTRY(n)                 \
126         (offsetof(struct kretprobe_trace_entry, args) + \
127         (sizeof(unsigned long) * (n)))
128
129 /*
130  * trace_flag_type is an enumeration that holds different
131  * states when a trace occurs. These are:
132  *  IRQS_OFF            - interrupts were disabled
133  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
134  *  NEED_RESCHED        - reschedule is requested
135  *  HARDIRQ             - inside an interrupt handler
136  *  SOFTIRQ             - inside a softirq handler
137  */
138 enum trace_flag_type {
139         TRACE_FLAG_IRQS_OFF             = 0x01,
140         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
141         TRACE_FLAG_NEED_RESCHED         = 0x04,
142         TRACE_FLAG_HARDIRQ              = 0x08,
143         TRACE_FLAG_SOFTIRQ              = 0x10,
144 };
145
146 #define TRACE_BUF_SIZE          1024
147
148 /*
149  * The CPU trace array - it consists of thousands of trace entries
150  * plus some other descriptor data: (for example which task started
151  * the trace, etc.)
152  */
153 struct trace_array_cpu {
154         atomic_t                disabled;
155         void                    *buffer_page;   /* ring buffer spare */
156
157         unsigned long           saved_latency;
158         unsigned long           critical_start;
159         unsigned long           critical_end;
160         unsigned long           critical_sequence;
161         unsigned long           nice;
162         unsigned long           policy;
163         unsigned long           rt_priority;
164         unsigned long           skipped_entries;
165         cycle_t                 preempt_timestamp;
166         pid_t                   pid;
167         uid_t                   uid;
168         char                    comm[TASK_COMM_LEN];
169 };
170
171 /*
172  * The trace array - an array of per-CPU trace arrays. This is the
173  * highest level data structure that individual tracers deal with.
174  * They have on/off state as well:
175  */
176 struct trace_array {
177         struct ring_buffer      *buffer;
178         unsigned long           entries;
179         int                     cpu;
180         cycle_t                 time_start;
181         struct task_struct      *waiter;
182         struct trace_array_cpu  *data[NR_CPUS];
183 };
184
185 #define FTRACE_CMP_TYPE(var, type) \
186         __builtin_types_compatible_p(typeof(var), type *)
187
188 #undef IF_ASSIGN
189 #define IF_ASSIGN(var, entry, etype, id)                \
190         if (FTRACE_CMP_TYPE(var, etype)) {              \
191                 var = (typeof(var))(entry);             \
192                 WARN_ON(id && (entry)->type != id);     \
193                 break;                                  \
194         }
195
196 /* Will cause compile errors if type is not found. */
197 extern void __ftrace_bad_type(void);
198
199 /*
200  * The trace_assign_type is a verifier that the entry type is
201  * the same as the type being assigned. To add new types simply
202  * add a line with the following format:
203  *
204  * IF_ASSIGN(var, ent, type, id);
205  *
206  *  Where "type" is the trace type that includes the trace_entry
207  *  as the "ent" item. And "id" is the trace identifier that is
208  *  used in the trace_type enum.
209  *
210  *  If the type can have more than one id, then use zero.
211  */
212 #define trace_assign_type(var, ent)                                     \
213         do {                                                            \
214                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
215                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
216                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
217                 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
218                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
219                 IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT); \
220                 IF_ASSIGN(var, ent, struct special_entry, 0);           \
221                 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
222                           TRACE_MMIO_RW);                               \
223                 IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
224                           TRACE_MMIO_MAP);                              \
225                 IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
226                 IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
227                 IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
228                 IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,      \
229                           TRACE_GRAPH_ENT);             \
230                 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,      \
231                           TRACE_GRAPH_RET);             \
232                 IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
233                 IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,       \
234                           TRACE_KMEM_ALLOC);    \
235                 IF_ASSIGN(var, ent, struct kmemtrace_free_entry,        \
236                           TRACE_KMEM_FREE);     \
237                 IF_ASSIGN(var, ent, struct ksym_trace_entry, TRACE_KSYM);\
238                 __ftrace_bad_type();                                    \
239         } while (0)
240
241 /*
242  * An option specific to a tracer. This is a boolean value.
243  * The bit is the bit index that sets its value on the
244  * flags value in struct tracer_flags.
245  */
246 struct tracer_opt {
247         const char      *name; /* Will appear on the trace_options file */
248         u32             bit; /* Mask assigned in val field in tracer_flags */
249 };
250
251 /*
252  * The set of specific options for a tracer. Your tracer
253  * have to set the initial value of the flags val.
254  */
255 struct tracer_flags {
256         u32                     val;
257         struct tracer_opt       *opts;
258 };
259
260 /* Makes more easy to define a tracer opt */
261 #define TRACER_OPT(s, b)        .name = #s, .bit = b
262
263
264 /**
265  * struct tracer - a specific tracer and its callbacks to interact with debugfs
266  * @name: the name chosen to select it on the available_tracers file
267  * @init: called when one switches to this tracer (echo name > current_tracer)
268  * @reset: called when one switches to another tracer
269  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
270  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
271  * @open: called when the trace file is opened
272  * @pipe_open: called when the trace_pipe file is opened
273  * @wait_pipe: override how the user waits for traces on trace_pipe
274  * @close: called when the trace file is released
275  * @read: override the default read callback on trace_pipe
276  * @splice_read: override the default splice_read callback on trace_pipe
277  * @selftest: selftest to run on boot (see trace_selftest.c)
278  * @print_headers: override the first lines that describe your columns
279  * @print_line: callback that prints a trace
280  * @set_flag: signals one of your private flags changed (trace_options file)
281  * @flags: your private flags
282  */
283 struct tracer {
284         const char              *name;
285         int                     (*init)(struct trace_array *tr);
286         void                    (*reset)(struct trace_array *tr);
287         void                    (*start)(struct trace_array *tr);
288         void                    (*stop)(struct trace_array *tr);
289         void                    (*open)(struct trace_iterator *iter);
290         void                    (*pipe_open)(struct trace_iterator *iter);
291         void                    (*wait_pipe)(struct trace_iterator *iter);
292         void                    (*close)(struct trace_iterator *iter);
293         ssize_t                 (*read)(struct trace_iterator *iter,
294                                         struct file *filp, char __user *ubuf,
295                                         size_t cnt, loff_t *ppos);
296         ssize_t                 (*splice_read)(struct trace_iterator *iter,
297                                                struct file *filp,
298                                                loff_t *ppos,
299                                                struct pipe_inode_info *pipe,
300                                                size_t len,
301                                                unsigned int flags);
302 #ifdef CONFIG_FTRACE_STARTUP_TEST
303         int                     (*selftest)(struct tracer *trace,
304                                             struct trace_array *tr);
305 #endif
306         void                    (*print_header)(struct seq_file *m);
307         enum print_line_t       (*print_line)(struct trace_iterator *iter);
308         /* If you handled the flag setting, return 0 */
309         int                     (*set_flag)(u32 old_flags, u32 bit, int set);
310         struct tracer           *next;
311         int                     print_max;
312         struct tracer_flags     *flags;
313 };
314
315
316 #define TRACE_PIPE_ALL_CPU      -1
317
318 int tracer_init(struct tracer *t, struct trace_array *tr);
319 int tracing_is_enabled(void);
320 void trace_wake_up(void);
321 void tracing_reset(struct trace_array *tr, int cpu);
322 void tracing_reset_online_cpus(struct trace_array *tr);
323 void tracing_reset_current(int cpu);
324 void tracing_reset_current_online_cpus(void);
325 int tracing_open_generic(struct inode *inode, struct file *filp);
326 struct dentry *trace_create_file(const char *name,
327                                  mode_t mode,
328                                  struct dentry *parent,
329                                  void *data,
330                                  const struct file_operations *fops);
331
332 struct dentry *tracing_init_dentry(void);
333 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
334
335 struct ring_buffer_event;
336
337 struct ring_buffer_event *
338 trace_buffer_lock_reserve(struct ring_buffer *buffer,
339                           int type,
340                           unsigned long len,
341                           unsigned long flags,
342                           int pc);
343 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
344                                 struct ring_buffer_event *event,
345                                 unsigned long flags, int pc);
346
347 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
348                                                 struct trace_array_cpu *data);
349
350 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
351                                           int *ent_cpu, u64 *ent_ts);
352
353 void default_wait_pipe(struct trace_iterator *iter);
354 void poll_wait_pipe(struct trace_iterator *iter);
355
356 void ftrace(struct trace_array *tr,
357                             struct trace_array_cpu *data,
358                             unsigned long ip,
359                             unsigned long parent_ip,
360                             unsigned long flags, int pc);
361 void tracing_sched_switch_trace(struct trace_array *tr,
362                                 struct task_struct *prev,
363                                 struct task_struct *next,
364                                 unsigned long flags, int pc);
365
366 void tracing_sched_wakeup_trace(struct trace_array *tr,
367                                 struct task_struct *wakee,
368                                 struct task_struct *cur,
369                                 unsigned long flags, int pc);
370 void trace_special(struct trace_array *tr,
371                    struct trace_array_cpu *data,
372                    unsigned long arg1,
373                    unsigned long arg2,
374                    unsigned long arg3, int pc);
375 void trace_function(struct trace_array *tr,
376                     unsigned long ip,
377                     unsigned long parent_ip,
378                     unsigned long flags, int pc);
379
380 void trace_graph_return(struct ftrace_graph_ret *trace);
381 int trace_graph_entry(struct ftrace_graph_ent *trace);
382 void set_graph_array(struct trace_array *tr);
383
384 void tracing_start_cmdline_record(void);
385 void tracing_stop_cmdline_record(void);
386 void tracing_sched_switch_assign_trace(struct trace_array *tr);
387 void tracing_stop_sched_switch_record(void);
388 void tracing_start_sched_switch_record(void);
389 int register_tracer(struct tracer *type);
390 void unregister_tracer(struct tracer *type);
391 int is_tracing_stopped(void);
392
393 extern int process_new_ksym_entry(char *ksymname, int op, unsigned long addr);
394
395 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
396
397 #ifdef CONFIG_TRACER_MAX_TRACE
398 extern unsigned long tracing_max_latency;
399 extern unsigned long tracing_thresh;
400
401 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
402 void update_max_tr_single(struct trace_array *tr,
403                           struct task_struct *tsk, int cpu);
404 #endif /* CONFIG_TRACER_MAX_TRACE */
405
406 #ifdef CONFIG_STACKTRACE
407 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
408                         int skip, int pc);
409
410 void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
411                             int pc);
412
413 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
414                    int pc);
415 #else
416 static inline void ftrace_trace_stack(struct trace_array *tr,
417                                       unsigned long flags, int skip, int pc)
418 {
419 }
420
421 static inline void ftrace_trace_userstack(struct trace_array *tr,
422                                           unsigned long flags, int pc)
423 {
424 }
425
426 static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
427                                  int skip, int pc)
428 {
429 }
430 #endif /* CONFIG_STACKTRACE */
431
432 extern cycle_t ftrace_now(int cpu);
433
434 extern void trace_find_cmdline(int pid, char comm[]);
435
436 #ifdef CONFIG_DYNAMIC_FTRACE
437 extern unsigned long ftrace_update_tot_cnt;
438 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
439 extern int DYN_FTRACE_TEST_NAME(void);
440 #endif
441
442 extern int ring_buffer_expanded;
443 extern bool tracing_selftest_disabled;
444 DECLARE_PER_CPU(local_t, ftrace_cpu_disabled);
445
446 #ifdef CONFIG_FTRACE_STARTUP_TEST
447 extern int trace_selftest_startup_function(struct tracer *trace,
448                                            struct trace_array *tr);
449 extern int trace_selftest_startup_function_graph(struct tracer *trace,
450                                                  struct trace_array *tr);
451 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
452                                           struct trace_array *tr);
453 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
454                                              struct trace_array *tr);
455 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
456                                                  struct trace_array *tr);
457 extern int trace_selftest_startup_wakeup(struct tracer *trace,
458                                          struct trace_array *tr);
459 extern int trace_selftest_startup_nop(struct tracer *trace,
460                                          struct trace_array *tr);
461 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
462                                                struct trace_array *tr);
463 extern int trace_selftest_startup_sysprof(struct tracer *trace,
464                                                struct trace_array *tr);
465 extern int trace_selftest_startup_branch(struct tracer *trace,
466                                          struct trace_array *tr);
467 extern int trace_selftest_startup_hw_branches(struct tracer *trace,
468                                               struct trace_array *tr);
469 extern int trace_selftest_startup_ksym(struct tracer *trace,
470                                          struct trace_array *tr);
471 #endif /* CONFIG_FTRACE_STARTUP_TEST */
472
473 extern void *head_page(struct trace_array_cpu *data);
474 extern unsigned long long ns2usecs(cycle_t nsec);
475 extern int
476 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
477 extern int
478 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
479 extern int
480 trace_array_vprintk(struct trace_array *tr,
481                     unsigned long ip, const char *fmt, va_list args);
482 int trace_array_printk(struct trace_array *tr,
483                        unsigned long ip, const char *fmt, ...);
484
485 extern unsigned long trace_flags;
486
487 extern int trace_clock_id;
488
489 /* Standard output formatting function used for function return traces */
490 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
491 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
492 extern enum print_line_t
493 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
494
495 #ifdef CONFIG_DYNAMIC_FTRACE
496 /* TODO: make this variable */
497 #define FTRACE_GRAPH_MAX_FUNCS          32
498 extern int ftrace_graph_count;
499 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
500
501 static inline int ftrace_graph_addr(unsigned long addr)
502 {
503         int i;
504
505         if (!ftrace_graph_count || test_tsk_trace_graph(current))
506                 return 1;
507
508         for (i = 0; i < ftrace_graph_count; i++) {
509                 if (addr == ftrace_graph_funcs[i])
510                         return 1;
511         }
512
513         return 0;
514 }
515 #else
516 static inline int ftrace_graph_addr(unsigned long addr)
517 {
518         return 1;
519 }
520 #endif /* CONFIG_DYNAMIC_FTRACE */
521 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
522 static inline enum print_line_t
523 print_graph_function(struct trace_iterator *iter)
524 {
525         return TRACE_TYPE_UNHANDLED;
526 }
527 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
528
529 extern struct list_head ftrace_pids;
530
531 #ifdef CONFIG_FUNCTION_TRACER
532 static inline int ftrace_trace_task(struct task_struct *task)
533 {
534         if (list_empty(&ftrace_pids))
535                 return 1;
536
537         return test_tsk_trace_trace(task);
538 }
539 #else
540 static inline int ftrace_trace_task(struct task_struct *task)
541 {
542         return 1;
543 }
544 #endif
545
546 /*
547  * struct trace_parser - servers for reading the user input separated by spaces
548  * @cont: set if the input is not complete - no final space char was found
549  * @buffer: holds the parsed user input
550  * @idx: user input lenght
551  * @size: buffer size
552  */
553 struct trace_parser {
554         bool            cont;
555         char            *buffer;
556         unsigned        idx;
557         unsigned        size;
558 };
559
560 static inline bool trace_parser_loaded(struct trace_parser *parser)
561 {
562         return (parser->idx != 0);
563 }
564
565 static inline bool trace_parser_cont(struct trace_parser *parser)
566 {
567         return parser->cont;
568 }
569
570 static inline void trace_parser_clear(struct trace_parser *parser)
571 {
572         parser->cont = false;
573         parser->idx = 0;
574 }
575
576 extern int trace_parser_get_init(struct trace_parser *parser, int size);
577 extern void trace_parser_put(struct trace_parser *parser);
578 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
579         size_t cnt, loff_t *ppos);
580
581 /*
582  * trace_iterator_flags is an enumeration that defines bit
583  * positions into trace_flags that controls the output.
584  *
585  * NOTE: These bits must match the trace_options array in
586  *       trace.c.
587  */
588 enum trace_iterator_flags {
589         TRACE_ITER_PRINT_PARENT         = 0x01,
590         TRACE_ITER_SYM_OFFSET           = 0x02,
591         TRACE_ITER_SYM_ADDR             = 0x04,
592         TRACE_ITER_VERBOSE              = 0x08,
593         TRACE_ITER_RAW                  = 0x10,
594         TRACE_ITER_HEX                  = 0x20,
595         TRACE_ITER_BIN                  = 0x40,
596         TRACE_ITER_BLOCK                = 0x80,
597         TRACE_ITER_STACKTRACE           = 0x100,
598         TRACE_ITER_SCHED_TREE           = 0x200,
599         TRACE_ITER_PRINTK               = 0x400,
600         TRACE_ITER_PREEMPTONLY          = 0x800,
601         TRACE_ITER_BRANCH               = 0x1000,
602         TRACE_ITER_ANNOTATE             = 0x2000,
603         TRACE_ITER_USERSTACKTRACE       = 0x4000,
604         TRACE_ITER_SYM_USEROBJ          = 0x8000,
605         TRACE_ITER_PRINTK_MSGONLY       = 0x10000,
606         TRACE_ITER_CONTEXT_INFO         = 0x20000, /* Print pid/cpu/time */
607         TRACE_ITER_LATENCY_FMT          = 0x40000,
608         TRACE_ITER_SLEEP_TIME           = 0x80000,
609         TRACE_ITER_GRAPH_TIME           = 0x100000,
610 };
611
612 /*
613  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
614  * control the output of kernel symbols.
615  */
616 #define TRACE_ITER_SYM_MASK \
617         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
618
619 extern struct tracer nop_trace;
620
621 /**
622  * ftrace_preempt_disable - disable preemption scheduler safe
623  *
624  * When tracing can happen inside the scheduler, there exists
625  * cases that the tracing might happen before the need_resched
626  * flag is checked. If this happens and the tracer calls
627  * preempt_enable (after a disable), a schedule might take place
628  * causing an infinite recursion.
629  *
630  * To prevent this, we read the need_resched flag before
631  * disabling preemption. When we want to enable preemption we
632  * check the flag, if it is set, then we call preempt_enable_no_resched.
633  * Otherwise, we call preempt_enable.
634  *
635  * The rational for doing the above is that if need_resched is set
636  * and we have yet to reschedule, we are either in an atomic location
637  * (where we do not need to check for scheduling) or we are inside
638  * the scheduler and do not want to resched.
639  */
640 static inline int ftrace_preempt_disable(void)
641 {
642         int resched;
643
644         resched = need_resched();
645         preempt_disable_notrace();
646
647         return resched;
648 }
649
650 /**
651  * ftrace_preempt_enable - enable preemption scheduler safe
652  * @resched: the return value from ftrace_preempt_disable
653  *
654  * This is a scheduler safe way to enable preemption and not miss
655  * any preemption checks. The disabled saved the state of preemption.
656  * If resched is set, then we are either inside an atomic or
657  * are inside the scheduler (we would have already scheduled
658  * otherwise). In this case, we do not want to call normal
659  * preempt_enable, but preempt_enable_no_resched instead.
660  */
661 static inline void ftrace_preempt_enable(int resched)
662 {
663         if (resched)
664                 preempt_enable_no_resched_notrace();
665         else
666                 preempt_enable_notrace();
667 }
668
669 #ifdef CONFIG_BRANCH_TRACER
670 extern int enable_branch_tracing(struct trace_array *tr);
671 extern void disable_branch_tracing(void);
672 static inline int trace_branch_enable(struct trace_array *tr)
673 {
674         if (trace_flags & TRACE_ITER_BRANCH)
675                 return enable_branch_tracing(tr);
676         return 0;
677 }
678 static inline void trace_branch_disable(void)
679 {
680         /* due to races, always disable */
681         disable_branch_tracing();
682 }
683 #else
684 static inline int trace_branch_enable(struct trace_array *tr)
685 {
686         return 0;
687 }
688 static inline void trace_branch_disable(void)
689 {
690 }
691 #endif /* CONFIG_BRANCH_TRACER */
692
693 /* set ring buffers to default size if not already done so */
694 int tracing_update_buffers(void);
695
696 /* trace event type bit fields, not numeric */
697 enum {
698         TRACE_EVENT_TYPE_PRINTF         = 1,
699         TRACE_EVENT_TYPE_RAW            = 2,
700 };
701
702 struct ftrace_event_field {
703         struct list_head        link;
704         char                    *name;
705         char                    *type;
706         int                     filter_type;
707         int                     offset;
708         int                     size;
709         int                     is_signed;
710 };
711
712 struct event_filter {
713         int                     n_preds;
714         struct filter_pred      **preds;
715         char                    *filter_string;
716 };
717
718 struct event_subsystem {
719         struct list_head        list;
720         const char              *name;
721         struct dentry           *entry;
722         struct event_filter     *filter;
723         int                     nr_events;
724 };
725
726 struct filter_pred;
727 struct regex;
728
729 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
730                                  int val1, int val2);
731
732 typedef int (*regex_match_func)(char *str, struct regex *r, int len);
733
734 enum regex_type {
735         MATCH_FULL = 0,
736         MATCH_FRONT_ONLY,
737         MATCH_MIDDLE_ONLY,
738         MATCH_END_ONLY,
739 };
740
741 struct regex {
742         char                    pattern[MAX_FILTER_STR_VAL];
743         int                     len;
744         int                     field_len;
745         regex_match_func        match;
746 };
747
748 struct filter_pred {
749         filter_pred_fn_t        fn;
750         u64                     val;
751         struct regex            regex;
752         char                    *field_name;
753         int                     offset;
754         int                     not;
755         int                     op;
756         int                     pop_n;
757 };
758
759 extern enum regex_type
760 filter_parse_regex(char *buff, int len, char **search, int *not);
761 extern void print_event_filter(struct ftrace_event_call *call,
762                                struct trace_seq *s);
763 extern int apply_event_filter(struct ftrace_event_call *call,
764                               char *filter_string);
765 extern int apply_subsystem_event_filter(struct event_subsystem *system,
766                                         char *filter_string);
767 extern void print_subsystem_event_filter(struct event_subsystem *system,
768                                          struct trace_seq *s);
769 extern int filter_assign_type(const char *type);
770
771 static inline int
772 filter_check_discard(struct ftrace_event_call *call, void *rec,
773                      struct ring_buffer *buffer,
774                      struct ring_buffer_event *event)
775 {
776         if (unlikely(call->filter_active) &&
777             !filter_match_preds(call->filter, rec)) {
778                 ring_buffer_discard_commit(buffer, event);
779                 return 1;
780         }
781
782         return 0;
783 }
784
785 extern struct mutex event_mutex;
786 extern struct list_head ftrace_events;
787
788 extern const char *__start___trace_bprintk_fmt[];
789 extern const char *__stop___trace_bprintk_fmt[];
790
791 #undef FTRACE_ENTRY
792 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print)             \
793         extern struct ftrace_event_call event_##call;
794 #undef FTRACE_ENTRY_DUP
795 #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)         \
796         FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
797 #include "trace_entries.h"
798
799 #endif /* _LINUX_KERNEL_TRACE_H */