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_BPRINTK,
  24         TRACE_SPECIAL,
  25         TRACE_MMIO_RW,
  26         TRACE_MMIO_MAP,
  27         TRACE_BRANCH,
  28         TRACE_BOOT_CALL,
  29         TRACE_BOOT_RET,
  30         TRACE_GRAPH_RET,
  31         TRACE_GRAPH_ENT,
  32         TRACE_USER_STACK,
  33         TRACE_HW_BRANCHES,
  34         TRACE_KMEM_ALLOC,
  35         TRACE_KMEM_FREE,
  36         TRACE_POWER,
  37         TRACE_BLK,
  38
  39         __TRACE_LAST_TYPE,
  40 };
  41
  42 /*
  43  * The trace entry - the most basic unit of tracing. This is what
  44  * is printed in the end as a single line in the trace output, such as:
  45  *
  46  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
  47  */
  48 struct trace_entry {
  49         unsigned char           type;
  50         unsigned char           flags;
  51         unsigned char           preempt_count;
  52         int                     pid;
  53         int                     tgid;
  54 };
  55
  56 /*
  57  * Function trace entry - function address and parent function addres:
  58  */
  59 struct ftrace_entry {
  60         struct trace_entry      ent;
  61         unsigned long           ip;
  62         unsigned long           parent_ip;
  63 };
  64
  65 /* Function call entry */
  66 struct ftrace_graph_ent_entry {
  67         struct trace_entry              ent;
  68         struct ftrace_graph_ent         graph_ent;
  69 };
  70
  71 /* Function return entry */
  72 struct ftrace_graph_ret_entry {
  73         struct trace_entry              ent;
  74         struct ftrace_graph_ret         ret;
  75 };
  76 extern struct tracer boot_tracer;
  77
  78 /*
  79  * Context switch trace entry - which task (and prio) we switched from/to:
  80  */
  81 struct ctx_switch_entry {
  82         struct trace_entry      ent;
  83         unsigned int            prev_pid;
  84         unsigned char           prev_prio;
  85         unsigned char           prev_state;
  86         unsigned int            next_pid;
  87         unsigned char           next_prio;
  88         unsigned char           next_state;
  89         unsigned int            next_cpu;
  90 };
  91
  92 /*
  93  * Special (free-form) trace entry:
  94  */
  95 struct special_entry {
  96         struct trace_entry      ent;
  97         unsigned long           arg1;
  98         unsigned long           arg2;
  99         unsigned long           arg3;
 100 };
 101
 102 /*
 103  * Stack-trace entry:
 104  */
 105
 106 #define FTRACE_STACK_ENTRIES    8
 107
 108 struct stack_entry {
 109         struct trace_entry      ent;
 110         unsigned long           caller[FTRACE_STACK_ENTRIES];
 111 };
 112
 113 struct userstack_entry {
 114         struct trace_entry      ent;
 115         unsigned long           caller[FTRACE_STACK_ENTRIES];
 116 };
 117
 118 /*
 119  * trace_printk entry:
 120  */
 121 struct print_entry {
 122         struct trace_entry      ent;
 123         unsigned long           ip;
 124         int                     depth;
 125         char                    buf[];
 126 };
 127
 128 struct bprintk_entry {
 129         struct trace_entry ent;
 130         unsigned long ip;
 131         const char *fmt;
 132         u32 buf[];
 133 };
 134 #ifdef CONFIG_TRACE_BPRINTK
 135 extern int trace_bprintk_enable;
 136 #endif
 137
 138 #define TRACE_OLD_SIZE          88
 139
 140 struct trace_field_cont {
 141         unsigned char           type;
 142         /* Temporary till we get rid of this completely */
 143         char                    buf[TRACE_OLD_SIZE - 1];
 144 };
 145
 146 struct trace_mmiotrace_rw {
 147         struct trace_entry      ent;
 148         struct mmiotrace_rw     rw;
 149 };
 150
 151 struct trace_mmiotrace_map {
 152         struct trace_entry      ent;
 153         struct mmiotrace_map    map;
 154 };
 155
 156 struct trace_boot_call {
 157         struct trace_entry      ent;
 158         struct boot_trace_call boot_call;
 159 };
 160
 161 struct trace_boot_ret {
 162         struct trace_entry      ent;
 163         struct boot_trace_ret boot_ret;
 164 };
 165
 166 #define TRACE_FUNC_SIZE 30
 167 #define TRACE_FILE_SIZE 20
 168 struct trace_branch {
 169         struct trace_entry      ent;
 170         unsigned                line;
 171         char                    func[TRACE_FUNC_SIZE+1];
 172         char                    file[TRACE_FILE_SIZE+1];
 173         char                    correct;
 174 };
 175
 176 struct hw_branch_entry {
 177         struct trace_entry      ent;
 178         u64                     from;
 179         u64                     to;
 180 };
 181
 182 struct trace_power {
 183         struct trace_entry      ent;
 184         struct power_trace      state_data;
 185 };
 186
 187 struct kmemtrace_alloc_entry {
 188         struct trace_entry      ent;
 189         enum kmemtrace_type_id type_id;
 190         unsigned long call_site;
 191         const void *ptr;
 192         size_t bytes_req;
 193         size_t bytes_alloc;
 194         gfp_t gfp_flags;
 195         int node;
 196 };
 197
 198 struct kmemtrace_free_entry {
 199         struct trace_entry      ent;
 200         enum kmemtrace_type_id type_id;
 201         unsigned long call_site;
 202         const void *ptr;
 203 };
 204
 205 /*
 206  * trace_flag_type is an enumeration that holds different
 207  * states when a trace occurs. These are:
 208  *  IRQS_OFF            - interrupts were disabled
 209  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
 210  *  NEED_RESCED         - reschedule is requested
 211  *  HARDIRQ             - inside an interrupt handler
 212  *  SOFTIRQ             - inside a softirq handler
 213  */
 214 enum trace_flag_type {
 215         TRACE_FLAG_IRQS_OFF             = 0x01,
 216         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
 217         TRACE_FLAG_NEED_RESCHED         = 0x04,
 218         TRACE_FLAG_HARDIRQ              = 0x08,
 219         TRACE_FLAG_SOFTIRQ              = 0x10,
 220 };
 221
 222 #define TRACE_BUF_SIZE          1024
 223
 224 /*
 225  * The CPU trace array - it consists of thousands of trace entries
 226  * plus some other descriptor data: (for example which task started
 227  * the trace, etc.)
 228  */
 229 struct trace_array_cpu {
 230         atomic_t                disabled;
 231         void                    *buffer_page;   /* ring buffer spare */
 232
 233         /* these fields get copied into max-trace: */
 234         unsigned long           trace_idx;
 235         unsigned long           overrun;
 236         unsigned long           saved_latency;
 237         unsigned long           critical_start;
 238         unsigned long           critical_end;
 239         unsigned long           critical_sequence;
 240         unsigned long           nice;
 241         unsigned long           policy;
 242         unsigned long           rt_priority;
 243         cycle_t                 preempt_timestamp;
 244         pid_t                   pid;
 245         uid_t                   uid;
 246         char                    comm[TASK_COMM_LEN];
 247 };
 248
 249 struct trace_iterator;
 250
 251 /*
 252  * The trace array - an array of per-CPU trace arrays. This is the
 253  * highest level data structure that individual tracers deal with.
 254  * They have on/off state as well:
 255  */
 256 struct trace_array {
 257         struct ring_buffer      *buffer;
 258         unsigned long           entries;
 259         int                     cpu;
 260         cycle_t                 time_start;
 261         struct task_struct      *waiter;
 262         struct trace_array_cpu  *data[NR_CPUS];
 263 };
 264
 265 #define FTRACE_CMP_TYPE(var, type) \
 266         __builtin_types_compatible_p(typeof(var), type *)
 267
 268 #undef IF_ASSIGN
 269 #define IF_ASSIGN(var, entry, etype, id)                \
 270         if (FTRACE_CMP_TYPE(var, etype)) {              \
 271                 var = (typeof(var))(entry);             \
 272                 WARN_ON(id && (entry)->type != id);     \
 273                 break;                                  \
 274         }
 275
 276 /* Will cause compile errors if type is not found. */
 277 extern void __ftrace_bad_type(void);
 278
 279 /*
 280  * The trace_assign_type is a verifier that the entry type is
 281  * the same as the type being assigned. To add new types simply
 282  * add a line with the following format:
 283  *
 284  * IF_ASSIGN(var, ent, type, id);
 285  *
 286  *  Where "type" is the trace type that includes the trace_entry
 287  *  as the "ent" item. And "id" is the trace identifier that is
 288  *  used in the trace_type enum.
 289  *
 290  *  If the type can have more than one id, then use zero.
 291  */
 292 #define trace_assign_type(var, ent)                                     \
 293         do {                                                            \
 294                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
 295                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
 296                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
 297                 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
 298                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
 299                 IF_ASSIGN(var, ent, struct bprintk_entry, TRACE_BPRINTK);\
 300                 IF_ASSIGN(var, ent, struct special_entry, 0);           \
 301                 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
 302                           TRACE_MMIO_RW);                               \
 303                 IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
 304                           TRACE_MMIO_MAP);                              \
 305                 IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
 306                 IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
 307                 IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
 308                 IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,      \
 309                           TRACE_GRAPH_ENT);             \
 310                 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,      \
 311                           TRACE_GRAPH_RET);             \
 312                 IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
 313                 IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
 314                 IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,       \
 315                           TRACE_KMEM_ALLOC);    \
 316                 IF_ASSIGN(var, ent, struct kmemtrace_free_entry,        \
 317                           TRACE_KMEM_FREE);     \
 318                 __ftrace_bad_type();                                    \
 319         } while (0)
 320
 321 /* Return values for print_line callback */
 322 enum print_line_t {
 323         TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
 324         TRACE_TYPE_HANDLED      = 1,
 325         TRACE_TYPE_UNHANDLED    = 2,    /* Relay to other output functions */
 326         TRACE_TYPE_NO_CONSUME   = 3     /* Handled but ask to not consume */
 327 };
 328
 329
 330 /*
 331  * An option specific to a tracer. This is a boolean value.
 332  * The bit is the bit index that sets its value on the
 333  * flags value in struct tracer_flags.
 334  */
 335 struct tracer_opt {
 336         const char      *name; /* Will appear on the trace_options file */
 337         u32             bit; /* Mask assigned in val field in tracer_flags */
 338 };
 339
 340 /*
 341  * The set of specific options for a tracer. Your tracer
 342  * have to set the initial value of the flags val.
 343  */
 344 struct tracer_flags {
 345         u32                     val;
 346         struct tracer_opt       *opts;
 347 };
 348
 349 /* Makes more easy to define a tracer opt */
 350 #define TRACER_OPT(s, b)        .name = #s, .bit = b
 351
 352
 353 /**
 354  * struct tracer - a specific tracer and its callbacks to interact with debugfs
 355  * @name: the name chosen to select it on the available_tracers file
 356  * @init: called when one switches to this tracer (echo name > current_tracer)
 357  * @reset: called when one switches to another tracer
 358  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
 359  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
 360  * @open: called when the trace file is opened
 361  * @pipe_open: called when the trace_pipe file is opened
 362  * @wait_pipe: override how the user waits for traces on trace_pipe
 363  * @close: called when the trace file is released
 364  * @read: override the default read callback on trace_pipe
 365  * @splice_read: override the default splice_read callback on trace_pipe
 366  * @selftest: selftest to run on boot (see trace_selftest.c)
 367  * @print_headers: override the first lines that describe your columns
 368  * @print_line: callback that prints a trace
 369  * @set_flag: signals one of your private flags changed (trace_options file)
 370  * @flags: your private flags
 371  */
 372 struct tracer {
 373         const char              *name;
 374         int                     (*init)(struct trace_array *tr);
 375         void                    (*reset)(struct trace_array *tr);
 376         void                    (*start)(struct trace_array *tr);
 377         void                    (*stop)(struct trace_array *tr);
 378         void                    (*open)(struct trace_iterator *iter);
 379         void                    (*pipe_open)(struct trace_iterator *iter);
 380         void                    (*wait_pipe)(struct trace_iterator *iter);
 381         void                    (*close)(struct trace_iterator *iter);
 382         ssize_t                 (*read)(struct trace_iterator *iter,
 383                                         struct file *filp, char __user *ubuf,
 384                                         size_t cnt, loff_t *ppos);
 385         ssize_t                 (*splice_read)(struct trace_iterator *iter,
 386                                                struct file *filp,
 387                                                loff_t *ppos,
 388                                                struct pipe_inode_info *pipe,
 389                                                size_t len,
 390                                                unsigned int flags);
 391 #ifdef CONFIG_FTRACE_STARTUP_TEST
 392         int                     (*selftest)(struct tracer *trace,
 393                                             struct trace_array *tr);
 394 #endif
 395         void                    (*print_header)(struct seq_file *m);
 396         enum print_line_t       (*print_line)(struct trace_iterator *iter);
 397         /* If you handled the flag setting, return 0 */
 398         int                     (*set_flag)(u32 old_flags, u32 bit, int set);
 399         struct tracer           *next;
 400         int                     print_max;
 401         struct tracer_flags     *flags;
 402         struct tracer_stat      *stats;
 403 };
 404
 405 struct trace_seq {
 406         unsigned char           buffer[PAGE_SIZE];
 407         unsigned int            len;
 408         unsigned int            readpos;
 409 };
 410
 411 static inline void
 412 trace_seq_init(struct trace_seq *s)
 413 {
 414         s->len = 0;
 415         s->readpos = 0;
 416 }
 417
 418
 419 #define TRACE_PIPE_ALL_CPU      -1
 420
 421 /*
 422  * Trace iterator - used by printout routines who present trace
 423  * results to users and which routines might sleep, etc:
 424  */
 425 struct trace_iterator {
 426         struct trace_array      *tr;
 427         struct tracer           *trace;
 428         void                    *private;
 429         int                     cpu_file;
 430         struct mutex            mutex;
 431         struct ring_buffer_iter *buffer_iter[NR_CPUS];
 432
 433         /* The below is zeroed out in pipe_read */
 434         struct trace_seq        seq;
 435         struct trace_entry      *ent;
 436         int                     cpu;
 437         u64                     ts;
 438
 439         unsigned long           iter_flags;
 440         loff_t                  pos;
 441         long                    idx;
 442
 443         cpumask_var_t           started;
 444 };
 445
 446 int tracer_init(struct tracer *t, struct trace_array *tr);
 447 int tracing_is_enabled(void);
 448 void trace_wake_up(void);
 449 void tracing_reset(struct trace_array *tr, int cpu);
 450 void tracing_reset_online_cpus(struct trace_array *tr);
 451 int tracing_open_generic(struct inode *inode, struct file *filp);
 452 struct dentry *tracing_init_dentry(void);
 453 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
 454
 455 struct ring_buffer_event;
 456
 457 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
 458                                                     unsigned char type,
 459                                                     unsigned long len,
 460                                                     unsigned long flags,
 461                                                     int pc);
 462 void trace_buffer_unlock_commit(struct trace_array *tr,
 463                                 struct ring_buffer_event *event,
 464                                 unsigned long flags, int pc);
 465
 466 struct ring_buffer_event *
 467 trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
 468                                   unsigned long flags, int pc);
 469 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
 470                                         unsigned long flags, int pc);
 471
 472 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 473                                                 struct trace_array_cpu *data);
 474
 475 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 476                                           int *ent_cpu, u64 *ent_ts);
 477
 478 void tracing_generic_entry_update(struct trace_entry *entry,
 479                                   unsigned long flags,
 480                                   int pc);
 481
 482 void default_wait_pipe(struct trace_iterator *iter);
 483 void poll_wait_pipe(struct trace_iterator *iter);
 484
 485 void ftrace(struct trace_array *tr,
 486                             struct trace_array_cpu *data,
 487                             unsigned long ip,
 488                             unsigned long parent_ip,
 489                             unsigned long flags, int pc);
 490 void tracing_sched_switch_trace(struct trace_array *tr,
 491                                 struct task_struct *prev,
 492                                 struct task_struct *next,
 493                                 unsigned long flags, int pc);
 494 void tracing_record_cmdline(struct task_struct *tsk);
 495
 496 void tracing_sched_wakeup_trace(struct trace_array *tr,
 497                                 struct task_struct *wakee,
 498                                 struct task_struct *cur,
 499                                 unsigned long flags, int pc);
 500 void trace_special(struct trace_array *tr,
 501                    struct trace_array_cpu *data,
 502                    unsigned long arg1,
 503                    unsigned long arg2,
 504                    unsigned long arg3, int pc);
 505 void trace_function(struct trace_array *tr,
 506                     unsigned long ip,
 507                     unsigned long parent_ip,
 508                     unsigned long flags, int pc);
 509
 510 void trace_graph_return(struct ftrace_graph_ret *trace);
 511 int trace_graph_entry(struct ftrace_graph_ent *trace);
 512
 513 void tracing_start_cmdline_record(void);
 514 void tracing_stop_cmdline_record(void);
 515 void tracing_sched_switch_assign_trace(struct trace_array *tr);
 516 void tracing_stop_sched_switch_record(void);
 517 void tracing_start_sched_switch_record(void);
 518 int register_tracer(struct tracer *type);
 519 void unregister_tracer(struct tracer *type);
 520
 521 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 522
 523 extern unsigned long tracing_max_latency;
 524 extern unsigned long tracing_thresh;
 525
 526 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
 527 void update_max_tr_single(struct trace_array *tr,
 528                           struct task_struct *tsk, int cpu);
 529
 530 void __trace_stack(struct trace_array *tr,
 531                    unsigned long flags,
 532                    int skip, int pc);
 533
 534 extern cycle_t ftrace_now(int cpu);
 535
 536 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
 537 typedef void
 538 (*tracer_switch_func_t)(void *private,
 539                         void *__rq,
 540                         struct task_struct *prev,
 541                         struct task_struct *next);
 542
 543 struct tracer_switch_ops {
 544         tracer_switch_func_t            func;
 545         void                            *private;
 546         struct tracer_switch_ops        *next;
 547 };
 548 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
 549
 550 extern char *trace_find_cmdline(int pid);
 551
 552 #ifdef CONFIG_DYNAMIC_FTRACE
 553 extern unsigned long ftrace_update_tot_cnt;
 554 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
 555 extern int DYN_FTRACE_TEST_NAME(void);
 556 #endif
 557
 558 #ifdef CONFIG_FTRACE_STARTUP_TEST
 559 extern int trace_selftest_startup_function(struct tracer *trace,
 560                                            struct trace_array *tr);
 561 extern int trace_selftest_startup_function_graph(struct tracer *trace,
 562                                                  struct trace_array *tr);
 563 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
 564                                           struct trace_array *tr);
 565 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
 566                                              struct trace_array *tr);
 567 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
 568                                                  struct trace_array *tr);
 569 extern int trace_selftest_startup_wakeup(struct tracer *trace,
 570                                          struct trace_array *tr);
 571 extern int trace_selftest_startup_nop(struct tracer *trace,
 572                                          struct trace_array *tr);
 573 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
 574                                                struct trace_array *tr);
 575 extern int trace_selftest_startup_sysprof(struct tracer *trace,
 576                                                struct trace_array *tr);
 577 extern int trace_selftest_startup_branch(struct tracer *trace,
 578                                          struct trace_array *tr);
 579 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 580
 581 extern void *head_page(struct trace_array_cpu *data);
 582 extern long ns2usecs(cycle_t nsec);
 583 extern int
 584 trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args);
 585
 586 extern unsigned long trace_flags;
 587
 588 /* Standard output formatting function used for function return traces */
 589 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 590 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
 591
 592 #ifdef CONFIG_DYNAMIC_FTRACE
 593 /* TODO: make this variable */
 594 #define FTRACE_GRAPH_MAX_FUNCS          32
 595 extern int ftrace_graph_count;
 596 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
 597
 598 static inline int ftrace_graph_addr(unsigned long addr)
 599 {
 600         int i;
 601
 602         if (!ftrace_graph_count || test_tsk_trace_graph(current))
 603                 return 1;
 604
 605         for (i = 0; i < ftrace_graph_count; i++) {
 606                 if (addr == ftrace_graph_funcs[i])
 607                         return 1;
 608         }
 609
 610         return 0;
 611 }
 612 #else
 613 static inline int ftrace_trace_addr(unsigned long addr)
 614 {
 615         return 1;
 616 }
 617 static inline int ftrace_graph_addr(unsigned long addr)
 618 {
 619         return 1;
 620 }
 621 #endif /* CONFIG_DYNAMIC_FTRACE */
 622
 623 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
 624 static inline enum print_line_t
 625 print_graph_function(struct trace_iterator *iter)
 626 {
 627         return TRACE_TYPE_UNHANDLED;
 628 }
 629 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 630
 631 extern struct pid *ftrace_pid_trace;
 632
 633 static inline int ftrace_trace_task(struct task_struct *task)
 634 {
 635         if (!ftrace_pid_trace)
 636                 return 1;
 637
 638         return test_tsk_trace_trace(task);
 639 }
 640
 641 /*
 642  * trace_iterator_flags is an enumeration that defines bit
 643  * positions into trace_flags that controls the output.
 644  *
 645  * NOTE: These bits must match the trace_options array in
 646  *       trace.c.
 647  */
 648 enum trace_iterator_flags {
 649         TRACE_ITER_PRINT_PARENT         = 0x01,
 650         TRACE_ITER_SYM_OFFSET           = 0x02,
 651         TRACE_ITER_SYM_ADDR             = 0x04,
 652         TRACE_ITER_VERBOSE              = 0x08,
 653         TRACE_ITER_RAW                  = 0x10,
 654         TRACE_ITER_HEX                  = 0x20,
 655         TRACE_ITER_BIN                  = 0x40,
 656         TRACE_ITER_BLOCK                = 0x80,
 657         TRACE_ITER_STACKTRACE           = 0x100,
 658         TRACE_ITER_SCHED_TREE           = 0x200,
 659         TRACE_ITER_PRINTK               = 0x400,
 660         TRACE_ITER_PREEMPTONLY          = 0x800,
 661         TRACE_ITER_BRANCH               = 0x1000,
 662         TRACE_ITER_ANNOTATE             = 0x2000,
 663         TRACE_ITER_USERSTACKTRACE       = 0x4000,
 664         TRACE_ITER_SYM_USEROBJ          = 0x8000,
 665         TRACE_ITER_PRINTK_MSGONLY       = 0x10000,
 666         TRACE_ITER_CONTEXT_INFO         = 0x20000, /* Print pid/cpu/time */
 667         TRACE_ITER_LATENCY_FMT          = 0x40000,
 668 };
 669
 670 /*
 671  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
 672  * control the output of kernel symbols.
 673  */
 674 #define TRACE_ITER_SYM_MASK \
 675         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
 676
 677 extern struct tracer nop_trace;
 678
 679 /**
 680  * ftrace_preempt_disable - disable preemption scheduler safe
 681  *
 682  * When tracing can happen inside the scheduler, there exists
 683  * cases that the tracing might happen before the need_resched
 684  * flag is checked. If this happens and the tracer calls
 685  * preempt_enable (after a disable), a schedule might take place
 686  * causing an infinite recursion.
 687  *
 688  * To prevent this, we read the need_resched flag before
 689  * disabling preemption. When we want to enable preemption we
 690  * check the flag, if it is set, then we call preempt_enable_no_resched.
 691  * Otherwise, we call preempt_enable.
 692  *
 693  * The rational for doing the above is that if need_resched is set
 694  * and we have yet to reschedule, we are either in an atomic location
 695  * (where we do not need to check for scheduling) or we are inside
 696  * the scheduler and do not want to resched.
 697  */
 698 static inline int ftrace_preempt_disable(void)
 699 {
 700         int resched;
 701
 702         resched = need_resched();
 703         preempt_disable_notrace();
 704
 705         return resched;
 706 }
 707
 708 /**
 709  * ftrace_preempt_enable - enable preemption scheduler safe
 710  * @resched: the return value from ftrace_preempt_disable
 711  *
 712  * This is a scheduler safe way to enable preemption and not miss
 713  * any preemption checks. The disabled saved the state of preemption.
 714  * If resched is set, then we are either inside an atomic or
 715  * are inside the scheduler (we would have already scheduled
 716  * otherwise). In this case, we do not want to call normal
 717  * preempt_enable, but preempt_enable_no_resched instead.
 718  */
 719 static inline void ftrace_preempt_enable(int resched)
 720 {
 721         if (resched)
 722                 preempt_enable_no_resched_notrace();
 723         else
 724                 preempt_enable_notrace();
 725 }
 726
 727 #ifdef CONFIG_BRANCH_TRACER
 728 extern int enable_branch_tracing(struct trace_array *tr);
 729 extern void disable_branch_tracing(void);
 730 static inline int trace_branch_enable(struct trace_array *tr)
 731 {
 732         if (trace_flags & TRACE_ITER_BRANCH)
 733                 return enable_branch_tracing(tr);
 734         return 0;
 735 }
 736 static inline void trace_branch_disable(void)
 737 {
 738         /* due to races, always disable */
 739         disable_branch_tracing();
 740 }
 741 #else
 742 static inline int trace_branch_enable(struct trace_array *tr)
 743 {
 744         return 0;
 745 }
 746 static inline void trace_branch_disable(void)
 747 {
 748 }
 749 #endif /* CONFIG_BRANCH_TRACER */
 750
 751 /* trace event type bit fields, not numeric */
 752 enum {
 753         TRACE_EVENT_TYPE_PRINTF         = 1,
 754         TRACE_EVENT_TYPE_RAW            = 2,
 755 };
 756
 757 struct ftrace_event_call {
 758         char            *name;
 759         char            *system;
 760         struct dentry   *dir;
 761         int             enabled;
 762         int             (*regfunc)(void);
 763         void            (*unregfunc)(void);
 764         int             id;
 765         struct dentry   *raw_dir;
 766         int             raw_enabled;
 767         int             type;
 768         int             (*raw_init)(void);
 769         int             (*raw_reg)(void);
 770         void            (*raw_unreg)(void);
 771         int             (*show_format)(struct trace_seq *s);
 772 };
 773
 774 void event_trace_printk(unsigned long ip, const char *fmt, ...);
 775 extern struct ftrace_event_call __start_ftrace_events[];
 776 extern struct ftrace_event_call __stop_ftrace_events[];
 777
 778 #endif /* _LINUX_KERNEL_TRACE_H */