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