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