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   1 #ifndef _LINUX_KERNEL_TRACE_H
   2 #define _LINUX_KERNEL_TRACE_H
   3
   4 #include <linux/fs.h>
   5 #include <asm/atomic.h>
   6 #include <linux/sched.h>
   7 #include <linux/clocksource.h>
   8 #include <linux/ring_buffer.h>
   9 #include <linux/mmiotrace.h>
  10 #include <linux/ftrace.h>
  11 #include <trace/boot.h>
  12 #include <trace/kmemtrace.h>
  13 #include <trace/power.h>
  14
  15 enum trace_type {
  16         __TRACE_FIRST_TYPE = 0,
  17
  18         TRACE_FN,
  19         TRACE_CTX,
  20         TRACE_WAKE,
  21         TRACE_STACK,
  22         TRACE_PRINT,
  23         TRACE_SPECIAL,
  24         TRACE_MMIO_RW,
  25         TRACE_MMIO_MAP,
  26         TRACE_BRANCH,
  27         TRACE_BOOT_CALL,
  28         TRACE_BOOT_RET,
  29         TRACE_GRAPH_RET,
  30         TRACE_GRAPH_ENT,
  31         TRACE_USER_STACK,
  32         TRACE_HW_BRANCHES,
  33         TRACE_SYSCALL_ENTER,
  34         TRACE_SYSCALL_EXIT,
  35         TRACE_KMEM_ALLOC,
  36         TRACE_KMEM_FREE,
  37         TRACE_POWER,
  38         TRACE_BLK,
  39
  40         __TRACE_LAST_TYPE,
  41 };
  42
  43 /*
  44  * The trace entry - the most basic unit of tracing. This is what
  45  * is printed in the end as a single line in the trace output, such as:
  46  *
  47  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
  48  */
  49 struct trace_entry {
  50         unsigned char           type;
  51         unsigned char           flags;
  52         unsigned char           preempt_count;
  53         int                     pid;
  54         int                     tgid;
  55 };
  56
  57 /*
  58  * Function trace entry - function address and parent function addres:
  59  */
  60 struct ftrace_entry {
  61         struct trace_entry      ent;
  62         unsigned long           ip;
  63         unsigned long           parent_ip;
  64 };
  65
  66 /* Function call entry */
  67 struct ftrace_graph_ent_entry {
  68         struct trace_entry              ent;
  69         struct ftrace_graph_ent         graph_ent;
  70 };
  71
  72 /* Function return entry */
  73 struct ftrace_graph_ret_entry {
  74         struct trace_entry              ent;
  75         struct ftrace_graph_ret         ret;
  76 };
  77 extern struct tracer boot_tracer;
  78
  79 /*
  80  * Context switch trace entry - which task (and prio) we switched from/to:
  81  */
  82 struct ctx_switch_entry {
  83         struct trace_entry      ent;
  84         unsigned int            prev_pid;
  85         unsigned char           prev_prio;
  86         unsigned char           prev_state;
  87         unsigned int            next_pid;
  88         unsigned char           next_prio;
  89         unsigned char           next_state;
  90         unsigned int            next_cpu;
  91 };
  92
  93 /*
  94  * Special (free-form) trace entry:
  95  */
  96 struct special_entry {
  97         struct trace_entry      ent;
  98         unsigned long           arg1;
  99         unsigned long           arg2;
 100         unsigned long           arg3;
 101 };
 102
 103 /*
 104  * Stack-trace entry:
 105  */
 106
 107 #define FTRACE_STACK_ENTRIES    8
 108
 109 struct stack_entry {
 110         struct trace_entry      ent;
 111         unsigned long           caller[FTRACE_STACK_ENTRIES];
 112 };
 113
 114 struct userstack_entry {
 115         struct trace_entry      ent;
 116         unsigned long           caller[FTRACE_STACK_ENTRIES];
 117 };
 118
 119 /*
 120  * trace_printk entry:
 121  */
 122 struct print_entry {
 123         struct trace_entry      ent;
 124         unsigned long           ip;
 125         int                     depth;
 126         const char              *fmt;
 127         u32                     buf[];
 128 };
 129
 130 #define TRACE_OLD_SIZE          88
 131
 132 struct trace_field_cont {
 133         unsigned char           type;
 134         /* Temporary till we get rid of this completely */
 135         char                    buf[TRACE_OLD_SIZE - 1];
 136 };
 137
 138 struct trace_mmiotrace_rw {
 139         struct trace_entry      ent;
 140         struct mmiotrace_rw     rw;
 141 };
 142
 143 struct trace_mmiotrace_map {
 144         struct trace_entry      ent;
 145         struct mmiotrace_map    map;
 146 };
 147
 148 struct trace_boot_call {
 149         struct trace_entry      ent;
 150         struct boot_trace_call boot_call;
 151 };
 152
 153 struct trace_boot_ret {
 154         struct trace_entry      ent;
 155         struct boot_trace_ret boot_ret;
 156 };
 157
 158 #define TRACE_FUNC_SIZE 30
 159 #define TRACE_FILE_SIZE 20
 160 struct trace_branch {
 161         struct trace_entry      ent;
 162         unsigned                line;
 163         char                    func[TRACE_FUNC_SIZE+1];
 164         char                    file[TRACE_FILE_SIZE+1];
 165         char                    correct;
 166 };
 167
 168 struct hw_branch_entry {
 169         struct trace_entry      ent;
 170         u64                     from;
 171         u64                     to;
 172 };
 173
 174 struct trace_power {
 175         struct trace_entry      ent;
 176         struct power_trace      state_data;
 177 };
 178
 179 struct kmemtrace_alloc_entry {
 180         struct trace_entry      ent;
 181         enum kmemtrace_type_id type_id;
 182         unsigned long call_site;
 183         const void *ptr;
 184         size_t bytes_req;
 185         size_t bytes_alloc;
 186         gfp_t gfp_flags;
 187         int node;
 188 };
 189
 190 struct kmemtrace_free_entry {
 191         struct trace_entry      ent;
 192         enum kmemtrace_type_id type_id;
 193         unsigned long call_site;
 194         const void *ptr;
 195 };
 196
 197 struct syscall_trace_enter {
 198         struct trace_entry      ent;
 199         int                     nr;
 200         unsigned long           args[];
 201 };
 202
 203 struct syscall_trace_exit {
 204         struct trace_entry      ent;
 205         int                     nr;
 206         unsigned long           ret;
 207 };
 208
 209
 210 /*
 211  * trace_flag_type is an enumeration that holds different
 212  * states when a trace occurs. These are:
 213  *  IRQS_OFF            - interrupts were disabled
 214  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
 215  *  NEED_RESCED         - reschedule is requested
 216  *  HARDIRQ             - inside an interrupt handler
 217  *  SOFTIRQ             - inside a softirq handler
 218  */
 219 enum trace_flag_type {
 220         TRACE_FLAG_IRQS_OFF             = 0x01,
 221         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
 222         TRACE_FLAG_NEED_RESCHED         = 0x04,
 223         TRACE_FLAG_HARDIRQ              = 0x08,
 224         TRACE_FLAG_SOFTIRQ              = 0x10,
 225 };
 226
 227 #define TRACE_BUF_SIZE          1024
 228
 229 /*
 230  * The CPU trace array - it consists of thousands of trace entries
 231  * plus some other descriptor data: (for example which task started
 232  * the trace, etc.)
 233  */
 234 struct trace_array_cpu {
 235         atomic_t                disabled;
 236         void                    *buffer_page;   /* ring buffer spare */
 237
 238         /* these fields get copied into max-trace: */
 239         unsigned long           trace_idx;
 240         unsigned long           overrun;
 241         unsigned long           saved_latency;
 242         unsigned long           critical_start;
 243         unsigned long           critical_end;
 244         unsigned long           critical_sequence;
 245         unsigned long           nice;
 246         unsigned long           policy;
 247         unsigned long           rt_priority;
 248         cycle_t                 preempt_timestamp;
 249         pid_t                   pid;
 250         uid_t                   uid;
 251         char                    comm[TASK_COMM_LEN];
 252 };
 253
 254 struct trace_iterator;
 255
 256 /*
 257  * The trace array - an array of per-CPU trace arrays. This is the
 258  * highest level data structure that individual tracers deal with.
 259  * They have on/off state as well:
 260  */
 261 struct trace_array {
 262         struct ring_buffer      *buffer;
 263         unsigned long           entries;
 264         int                     cpu;
 265         cycle_t                 time_start;
 266         struct task_struct      *waiter;
 267         struct trace_array_cpu  *data[NR_CPUS];
 268 };
 269
 270 #define FTRACE_CMP_TYPE(var, type) \
 271         __builtin_types_compatible_p(typeof(var), type *)
 272
 273 #undef IF_ASSIGN
 274 #define IF_ASSIGN(var, entry, etype, id)                \
 275         if (FTRACE_CMP_TYPE(var, etype)) {              \
 276                 var = (typeof(var))(entry);             \
 277                 WARN_ON(id && (entry)->type != id);     \
 278                 break;                                  \
 279         }
 280
 281 /* Will cause compile errors if type is not found. */
 282 extern void __ftrace_bad_type(void);
 283
 284 /*
 285  * The trace_assign_type is a verifier that the entry type is
 286  * the same as the type being assigned. To add new types simply
 287  * add a line with the following format:
 288  *
 289  * IF_ASSIGN(var, ent, type, id);
 290  *
 291  *  Where "type" is the trace type that includes the trace_entry
 292  *  as the "ent" item. And "id" is the trace identifier that is
 293  *  used in the trace_type enum.
 294  *
 295  *  If the type can have more than one id, then use zero.
 296  */
 297 #define trace_assign_type(var, ent)                                     \
 298         do {                                                            \
 299                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
 300                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
 301                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
 302                 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
 303                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
 304                 IF_ASSIGN(var, ent, struct special_entry, 0);           \
 305                 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
 306                           TRACE_MMIO_RW);                               \
 307                 IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
 308                           TRACE_MMIO_MAP);                              \
 309                 IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
 310                 IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
 311                 IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
 312                 IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,      \
 313                           TRACE_GRAPH_ENT);             \
 314                 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,      \
 315                           TRACE_GRAPH_RET);             \
 316                 IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
 317                 IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
 318                 IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,       \
 319                           TRACE_KMEM_ALLOC);    \
 320                 IF_ASSIGN(var, ent, struct kmemtrace_free_entry,        \
 321                           TRACE_KMEM_FREE);     \
 322                 IF_ASSIGN(var, ent, struct syscall_trace_enter,         \
 323                           TRACE_SYSCALL_ENTER);                         \
 324                 IF_ASSIGN(var, ent, struct syscall_trace_exit,          \
 325                           TRACE_SYSCALL_EXIT);                          \
 326                 __ftrace_bad_type();                                    \
 327         } while (0)
 328
 329 /* Return values for print_line callback */
 330 enum print_line_t {
 331         TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
 332         TRACE_TYPE_HANDLED      = 1,
 333         TRACE_TYPE_UNHANDLED    = 2,    /* Relay to other output functions */
 334         TRACE_TYPE_NO_CONSUME   = 3     /* Handled but ask to not consume */
 335 };
 336
 337
 338 /*
 339  * An option specific to a tracer. This is a boolean value.
 340  * The bit is the bit index that sets its value on the
 341  * flags value in struct tracer_flags.
 342  */
 343 struct tracer_opt {
 344         const char      *name; /* Will appear on the trace_options file */
 345         u32             bit; /* Mask assigned in val field in tracer_flags */
 346 };
 347
 348 /*
 349  * The set of specific options for a tracer. Your tracer
 350  * have to set the initial value of the flags val.
 351  */
 352 struct tracer_flags {
 353         u32                     val;
 354         struct tracer_opt       *opts;
 355 };
 356
 357 /* Makes more easy to define a tracer opt */
 358 #define TRACER_OPT(s, b)        .name = #s, .bit = b
 359
 360
 361 /**
 362  * struct tracer - a specific tracer and its callbacks to interact with debugfs
 363  * @name: the name chosen to select it on the available_tracers file
 364  * @init: called when one switches to this tracer (echo name > current_tracer)
 365  * @reset: called when one switches to another tracer
 366  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
 367  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
 368  * @open: called when the trace file is opened
 369  * @pipe_open: called when the trace_pipe file is opened
 370  * @wait_pipe: override how the user waits for traces on trace_pipe
 371  * @close: called when the trace file is released
 372  * @read: override the default read callback on trace_pipe
 373  * @splice_read: override the default splice_read callback on trace_pipe
 374  * @selftest: selftest to run on boot (see trace_selftest.c)
 375  * @print_headers: override the first lines that describe your columns
 376  * @print_line: callback that prints a trace
 377  * @set_flag: signals one of your private flags changed (trace_options file)
 378  * @flags: your private flags
 379  */
 380 struct tracer {
 381         const char              *name;
 382         int                     (*init)(struct trace_array *tr);
 383         void                    (*reset)(struct trace_array *tr);
 384         void                    (*start)(struct trace_array *tr);
 385         void                    (*stop)(struct trace_array *tr);
 386         void                    (*open)(struct trace_iterator *iter);
 387         void                    (*pipe_open)(struct trace_iterator *iter);
 388         void                    (*wait_pipe)(struct trace_iterator *iter);
 389         void                    (*close)(struct trace_iterator *iter);
 390         ssize_t                 (*read)(struct trace_iterator *iter,
 391                                         struct file *filp, char __user *ubuf,
 392                                         size_t cnt, loff_t *ppos);
 393         ssize_t                 (*splice_read)(struct trace_iterator *iter,
 394                                                struct file *filp,
 395                                                loff_t *ppos,
 396                                                struct pipe_inode_info *pipe,
 397                                                size_t len,
 398                                                unsigned int flags);
 399 #ifdef CONFIG_FTRACE_STARTUP_TEST
 400         int                     (*selftest)(struct tracer *trace,
 401                                             struct trace_array *tr);
 402 #endif
 403         void                    (*print_header)(struct seq_file *m);
 404         enum print_line_t       (*print_line)(struct trace_iterator *iter);
 405         /* If you handled the flag setting, return 0 */
 406         int                     (*set_flag)(u32 old_flags, u32 bit, int set);
 407         struct tracer           *next;
 408         int                     print_max;
 409         struct tracer_flags     *flags;
 410         struct tracer_stat      *stats;
 411 };
 412
 413 struct trace_seq {
 414         unsigned char           buffer[PAGE_SIZE];
 415         unsigned int            len;
 416         unsigned int            readpos;
 417 };
 418
 419 static inline void
 420 trace_seq_init(struct trace_seq *s)
 421 {
 422         s->len = 0;
 423         s->readpos = 0;
 424 }
 425
 426
 427 #define TRACE_PIPE_ALL_CPU      -1
 428
 429 /*
 430  * Trace iterator - used by printout routines who present trace
 431  * results to users and which routines might sleep, etc:
 432  */
 433 struct trace_iterator {
 434         struct trace_array      *tr;
 435         struct tracer           *trace;
 436         void                    *private;
 437         int                     cpu_file;
 438         struct mutex            mutex;
 439         struct ring_buffer_iter *buffer_iter[NR_CPUS];
 440
 441         /* The below is zeroed out in pipe_read */
 442         struct trace_seq        seq;
 443         struct trace_entry      *ent;
 444         int                     cpu;
 445         u64                     ts;
 446
 447         unsigned long           iter_flags;
 448         loff_t                  pos;
 449         long                    idx;
 450
 451         cpumask_var_t           started;
 452 };
 453
 454 int tracer_init(struct tracer *t, struct trace_array *tr);
 455 int tracing_is_enabled(void);
 456 void trace_wake_up(void);
 457 void tracing_reset(struct trace_array *tr, int cpu);
 458 void tracing_reset_online_cpus(struct trace_array *tr);
 459 int tracing_open_generic(struct inode *inode, struct file *filp);
 460 struct dentry *tracing_init_dentry(void);
 461 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
 462
 463 struct ring_buffer_event;
 464
 465 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
 466                                                     unsigned char type,
 467                                                     unsigned long len,
 468                                                     unsigned long flags,
 469                                                     int pc);
 470 void trace_buffer_unlock_commit(struct trace_array *tr,
 471                                 struct ring_buffer_event *event,
 472                                 unsigned long flags, int pc);
 473
 474 struct ring_buffer_event *
 475 trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
 476                                   unsigned long flags, int pc);
 477 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
 478                                         unsigned long flags, int pc);
 479
 480 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 481                                                 struct trace_array_cpu *data);
 482
 483 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 484                                           int *ent_cpu, u64 *ent_ts);
 485
 486 void tracing_generic_entry_update(struct trace_entry *entry,
 487                                   unsigned long flags,
 488                                   int pc);
 489
 490 void default_wait_pipe(struct trace_iterator *iter);
 491 void poll_wait_pipe(struct trace_iterator *iter);
 492
 493 void ftrace(struct trace_array *tr,
 494                             struct trace_array_cpu *data,
 495                             unsigned long ip,
 496                             unsigned long parent_ip,
 497                             unsigned long flags, int pc);
 498 void tracing_sched_switch_trace(struct trace_array *tr,
 499                                 struct task_struct *prev,
 500                                 struct task_struct *next,
 501                                 unsigned long flags, int pc);
 502 void tracing_record_cmdline(struct task_struct *tsk);
 503
 504 void tracing_sched_wakeup_trace(struct trace_array *tr,
 505                                 struct task_struct *wakee,
 506                                 struct task_struct *cur,
 507                                 unsigned long flags, int pc);
 508 void trace_special(struct trace_array *tr,
 509                    struct trace_array_cpu *data,
 510                    unsigned long arg1,
 511                    unsigned long arg2,
 512                    unsigned long arg3, int pc);
 513 void trace_function(struct trace_array *tr,
 514                     unsigned long ip,
 515                     unsigned long parent_ip,
 516                     unsigned long flags, int pc);
 517
 518 void trace_graph_return(struct ftrace_graph_ret *trace);
 519 int trace_graph_entry(struct ftrace_graph_ent *trace);
 520
 521 void tracing_start_cmdline_record(void);
 522 void tracing_stop_cmdline_record(void);
 523 void tracing_sched_switch_assign_trace(struct trace_array *tr);
 524 void tracing_stop_sched_switch_record(void);
 525 void tracing_start_sched_switch_record(void);
 526 int register_tracer(struct tracer *type);
 527 void unregister_tracer(struct tracer *type);
 528
 529 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 530
 531 extern unsigned long tracing_max_latency;
 532 extern unsigned long tracing_thresh;
 533
 534 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
 535 void update_max_tr_single(struct trace_array *tr,
 536                           struct task_struct *tsk, int cpu);
 537
 538 void __trace_stack(struct trace_array *tr,
 539                    unsigned long flags,
 540                    int skip, int pc);
 541
 542 extern cycle_t ftrace_now(int cpu);
 543
 544 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
 545 typedef void
 546 (*tracer_switch_func_t)(void *private,
 547                         void *__rq,
 548                         struct task_struct *prev,
 549                         struct task_struct *next);
 550
 551 struct tracer_switch_ops {
 552         tracer_switch_func_t            func;
 553         void                            *private;
 554         struct tracer_switch_ops        *next;
 555 };
 556 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
 557
 558 extern char *trace_find_cmdline(int pid);
 559
 560 #ifdef CONFIG_DYNAMIC_FTRACE
 561 extern unsigned long ftrace_update_tot_cnt;
 562 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
 563 extern int DYN_FTRACE_TEST_NAME(void);
 564 #endif
 565
 566 #ifdef CONFIG_FTRACE_STARTUP_TEST
 567 extern int trace_selftest_startup_function(struct tracer *trace,
 568                                            struct trace_array *tr);
 569 extern int trace_selftest_startup_function_graph(struct tracer *trace,
 570                                                  struct trace_array *tr);
 571 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
 572                                           struct trace_array *tr);
 573 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
 574                                              struct trace_array *tr);
 575 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
 576                                                  struct trace_array *tr);
 577 extern int trace_selftest_startup_wakeup(struct tracer *trace,
 578                                          struct trace_array *tr);
 579 extern int trace_selftest_startup_nop(struct tracer *trace,
 580                                          struct trace_array *tr);
 581 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
 582                                                struct trace_array *tr);
 583 extern int trace_selftest_startup_sysprof(struct tracer *trace,
 584                                                struct trace_array *tr);
 585 extern int trace_selftest_startup_branch(struct tracer *trace,
 586                                          struct trace_array *tr);
 587 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 588
 589 extern void *head_page(struct trace_array_cpu *data);
 590 extern long ns2usecs(cycle_t nsec);
 591 extern int
 592 trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args);
 593
 594 extern unsigned long trace_flags;
 595
 596 /* Standard output formatting function used for function return traces */
 597 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 598 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
 599
 600 #ifdef CONFIG_DYNAMIC_FTRACE
 601 /* TODO: make this variable */
 602 #define FTRACE_GRAPH_MAX_FUNCS          32
 603 extern int ftrace_graph_count;
 604 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
 605
 606 static inline int ftrace_graph_addr(unsigned long addr)
 607 {
 608         int i;
 609
 610         if (!ftrace_graph_count || test_tsk_trace_graph(current))
 611                 return 1;
 612
 613         for (i = 0; i < ftrace_graph_count; i++) {
 614                 if (addr == ftrace_graph_funcs[i])
 615                         return 1;
 616         }
 617
 618         return 0;
 619 }
 620 #else
 621 static inline int ftrace_trace_addr(unsigned long addr)
 622 {
 623         return 1;
 624 }
 625 static inline int ftrace_graph_addr(unsigned long addr)
 626 {
 627         return 1;
 628 }
 629 #endif /* CONFIG_DYNAMIC_FTRACE */
 630
 631 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
 632 static inline enum print_line_t
 633 print_graph_function(struct trace_iterator *iter)
 634 {
 635         return TRACE_TYPE_UNHANDLED;
 636 }
 637 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 638
 639 extern struct pid *ftrace_pid_trace;
 640
 641 static inline int ftrace_trace_task(struct task_struct *task)
 642 {
 643         if (!ftrace_pid_trace)
 644                 return 1;
 645
 646         return test_tsk_trace_trace(task);
 647 }
 648
 649 /*
 650  * trace_iterator_flags is an enumeration that defines bit
 651  * positions into trace_flags that controls the output.
 652  *
 653  * NOTE: These bits must match the trace_options array in
 654  *       trace.c.
 655  */
 656 enum trace_iterator_flags {
 657         TRACE_ITER_PRINT_PARENT         = 0x01,
 658         TRACE_ITER_SYM_OFFSET           = 0x02,
 659         TRACE_ITER_SYM_ADDR             = 0x04,
 660         TRACE_ITER_VERBOSE              = 0x08,
 661         TRACE_ITER_RAW                  = 0x10,
 662         TRACE_ITER_HEX                  = 0x20,
 663         TRACE_ITER_BIN                  = 0x40,
 664         TRACE_ITER_BLOCK                = 0x80,
 665         TRACE_ITER_STACKTRACE           = 0x100,
 666         TRACE_ITER_SCHED_TREE           = 0x200,
 667         TRACE_ITER_PRINTK               = 0x400,
 668         TRACE_ITER_PREEMPTONLY          = 0x800,
 669         TRACE_ITER_BRANCH               = 0x1000,
 670         TRACE_ITER_ANNOTATE             = 0x2000,
 671         TRACE_ITER_USERSTACKTRACE       = 0x4000,
 672         TRACE_ITER_SYM_USEROBJ          = 0x8000,
 673         TRACE_ITER_PRINTK_MSGONLY       = 0x10000,
 674         TRACE_ITER_CONTEXT_INFO         = 0x20000, /* Print pid/cpu/time */
 675         TRACE_ITER_LATENCY_FMT          = 0x40000,
 676 };
 677
 678 /*
 679  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
 680  * control the output of kernel symbols.
 681  */
 682 #define TRACE_ITER_SYM_MASK \
 683         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
 684
 685 extern struct tracer nop_trace;
 686
 687 /**
 688  * ftrace_preempt_disable - disable preemption scheduler safe
 689  *
 690  * When tracing can happen inside the scheduler, there exists
 691  * cases that the tracing might happen before the need_resched
 692  * flag is checked. If this happens and the tracer calls
 693  * preempt_enable (after a disable), a schedule might take place
 694  * causing an infinite recursion.
 695  *
 696  * To prevent this, we read the need_resched flag before
 697  * disabling preemption. When we want to enable preemption we
 698  * check the flag, if it is set, then we call preempt_enable_no_resched.
 699  * Otherwise, we call preempt_enable.
 700  *
 701  * The rational for doing the above is that if need_resched is set
 702  * and we have yet to reschedule, we are either in an atomic location
 703  * (where we do not need to check for scheduling) or we are inside
 704  * the scheduler and do not want to resched.
 705  */
 706 static inline int ftrace_preempt_disable(void)
 707 {
 708         int resched;
 709
 710         resched = need_resched();
 711         preempt_disable_notrace();
 712
 713         return resched;
 714 }
 715
 716 /**
 717  * ftrace_preempt_enable - enable preemption scheduler safe
 718  * @resched: the return value from ftrace_preempt_disable
 719  *
 720  * This is a scheduler safe way to enable preemption and not miss
 721  * any preemption checks. The disabled saved the state of preemption.
 722  * If resched is set, then we are either inside an atomic or
 723  * are inside the scheduler (we would have already scheduled
 724  * otherwise). In this case, we do not want to call normal
 725  * preempt_enable, but preempt_enable_no_resched instead.
 726  */
 727 static inline void ftrace_preempt_enable(int resched)
 728 {
 729         if (resched)
 730                 preempt_enable_no_resched_notrace();
 731         else
 732                 preempt_enable_notrace();
 733 }
 734
 735 #ifdef CONFIG_BRANCH_TRACER
 736 extern int enable_branch_tracing(struct trace_array *tr);
 737 extern void disable_branch_tracing(void);
 738 static inline int trace_branch_enable(struct trace_array *tr)
 739 {
 740         if (trace_flags & TRACE_ITER_BRANCH)
 741                 return enable_branch_tracing(tr);
 742         return 0;
 743 }
 744 static inline void trace_branch_disable(void)
 745 {
 746         /* due to races, always disable */
 747         disable_branch_tracing();
 748 }
 749 #else
 750 static inline int trace_branch_enable(struct trace_array *tr)
 751 {
 752         return 0;
 753 }
 754 static inline void trace_branch_disable(void)
 755 {
 756 }
 757 #endif /* CONFIG_BRANCH_TRACER */
 758
 759 /* trace event type bit fields, not numeric */
 760 enum {
 761         TRACE_EVENT_TYPE_PRINTF         = 1,
 762         TRACE_EVENT_TYPE_RAW            = 2,
 763 };
 764
 765 struct ftrace_event_call {
 766         char            *name;
 767         char            *system;
 768         struct dentry   *dir;
 769         int             enabled;
 770         int             (*regfunc)(void);
 771         void            (*unregfunc)(void);
 772         int             id;
 773         int             (*raw_init)(void);
 774         int             (*show_format)(struct trace_seq *s);
 775 };
 776
 777 void event_trace_printk(unsigned long ip, const char *fmt, ...);
 778 extern struct ftrace_event_call __start_ftrace_events[];
 779 extern struct ftrace_event_call __stop_ftrace_events[];
 780
 781 #endif /* _LINUX_KERNEL_TRACE_H */