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