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