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 #include <trace/power.h>
  15
  16 #include <linux/trace_seq.h>
  17 #include <linux/ftrace_event.h>
  18
  19 enum trace_type {
  20         __TRACE_FIRST_TYPE = 0,
  21
  22         TRACE_FN,
  23         TRACE_CTX,
  24         TRACE_WAKE,
  25         TRACE_STACK,
  26         TRACE_PRINT,
  27         TRACE_BPRINT,
  28         TRACE_SPECIAL,
  29         TRACE_MMIO_RW,
  30         TRACE_MMIO_MAP,
  31         TRACE_BRANCH,
  32         TRACE_BOOT_CALL,
  33         TRACE_BOOT_RET,
  34         TRACE_GRAPH_RET,
  35         TRACE_GRAPH_ENT,
  36         TRACE_USER_STACK,
  37         TRACE_HW_BRANCHES,
  38         TRACE_KMEM_ALLOC,
  39         TRACE_KMEM_FREE,
  40         TRACE_POWER,
  41         TRACE_BLK,
  42
  43         __TRACE_LAST_TYPE,
  44 };
  45
  46 enum kmemtrace_type_id {
  47         KMEMTRACE_TYPE_KMALLOC = 0,     /* kmalloc() or kfree(). */
  48         KMEMTRACE_TYPE_CACHE,           /* kmem_cache_*(). */
  49         KMEMTRACE_TYPE_PAGES,           /* __get_free_pages() and friends. */
  50 };
  51
  52 extern struct tracer boot_tracer;
  53
  54 #undef __field
  55 #define __field(type, item)             type    item;
  56
  57 #undef __field_struct
  58 #define __field_struct(type, item)      __field(type, item)
  59
  60 #undef __field_desc
  61 #define __field_desc(type, container, item)
  62
  63 #undef __array
  64 #define __array(type, item, size)       type    item[size];
  65
  66 #undef __array_desc
  67 #define __array_desc(type, container, item, size)
  68
  69 #undef __dynamic_array
  70 #define __dynamic_array(type, item)     type    item[];
  71
  72 #undef F_STRUCT
  73 #define F_STRUCT(args...)               args
  74
  75 #undef FTRACE_ENTRY
  76 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)     \
  77         struct struct_name {                                    \
  78                 struct trace_entry      ent;                    \
  79                 tstruct                                         \
  80         }
  81
  82 #undef TP_ARGS
  83 #define TP_ARGS(args...)        args
  84
  85 #undef FTRACE_ENTRY_DUP
  86 #define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)
  87
  88 #include "trace_entries.h"
  89
  90 /*
  91  * syscalls are special, and need special handling, this is why
  92  * they are not included in trace_entries.h
  93  */
  94 struct syscall_trace_enter {
  95         struct trace_entry      ent;
  96         int                     nr;
  97         unsigned long           args[];
  98 };
  99
 100 struct syscall_trace_exit {
 101         struct trace_entry      ent;
 102         int                     nr;
 103         unsigned long           ret;
 104 };
 105
 106 /*
 107  * trace_flag_type is an enumeration that holds different
 108  * states when a trace occurs. These are:
 109  *  IRQS_OFF            - interrupts were disabled
 110  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
 111  *  NEED_RESCHED        - reschedule is requested
 112  *  HARDIRQ             - inside an interrupt handler
 113  *  SOFTIRQ             - inside a softirq handler
 114  */
 115 enum trace_flag_type {
 116         TRACE_FLAG_IRQS_OFF             = 0x01,
 117         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
 118         TRACE_FLAG_NEED_RESCHED         = 0x04,
 119         TRACE_FLAG_HARDIRQ              = 0x08,
 120         TRACE_FLAG_SOFTIRQ              = 0x10,
 121 };
 122
 123 #define TRACE_BUF_SIZE          1024
 124
 125 /*
 126  * The CPU trace array - it consists of thousands of trace entries
 127  * plus some other descriptor data: (for example which task started
 128  * the trace, etc.)
 129  */
 130 struct trace_array_cpu {
 131         atomic_t                disabled;
 132         void                    *buffer_page;   /* ring buffer spare */
 133
 134         unsigned long           saved_latency;
 135         unsigned long           critical_start;
 136         unsigned long           critical_end;
 137         unsigned long           critical_sequence;
 138         unsigned long           nice;
 139         unsigned long           policy;
 140         unsigned long           rt_priority;
 141         unsigned long           skipped_entries;
 142         cycle_t                 preempt_timestamp;
 143         pid_t                   pid;
 144         uid_t                   uid;
 145         char                    comm[TASK_COMM_LEN];
 146 };
 147
 148 /*
 149  * The trace array - an array of per-CPU trace arrays. This is the
 150  * highest level data structure that individual tracers deal with.
 151  * They have on/off state as well:
 152  */
 153 struct trace_array {
 154         struct ring_buffer      *buffer;
 155         unsigned long           entries;
 156         int                     cpu;
 157         cycle_t                 time_start;
 158         struct task_struct      *waiter;
 159         struct trace_array_cpu  *data[NR_CPUS];
 160 };
 161
 162 #define FTRACE_CMP_TYPE(var, type) \
 163         __builtin_types_compatible_p(typeof(var), type *)
 164
 165 #undef IF_ASSIGN
 166 #define IF_ASSIGN(var, entry, etype, id)                \
 167         if (FTRACE_CMP_TYPE(var, etype)) {              \
 168                 var = (typeof(var))(entry);             \
 169                 WARN_ON(id && (entry)->type != id);     \
 170                 break;                                  \
 171         }
 172
 173 /* Will cause compile errors if type is not found. */
 174 extern void __ftrace_bad_type(void);
 175
 176 /*
 177  * The trace_assign_type is a verifier that the entry type is
 178  * the same as the type being assigned. To add new types simply
 179  * add a line with the following format:
 180  *
 181  * IF_ASSIGN(var, ent, type, id);
 182  *
 183  *  Where "type" is the trace type that includes the trace_entry
 184  *  as the "ent" item. And "id" is the trace identifier that is
 185  *  used in the trace_type enum.
 186  *
 187  *  If the type can have more than one id, then use zero.
 188  */
 189 #define trace_assign_type(var, ent)                                     \
 190         do {                                                            \
 191                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
 192                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
 193                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
 194                 IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
 195                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
 196                 IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT); \
 197                 IF_ASSIGN(var, ent, struct special_entry, 0);           \
 198                 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
 199                           TRACE_MMIO_RW);                               \
 200                 IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
 201                           TRACE_MMIO_MAP);                              \
 202                 IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
 203                 IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
 204                 IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
 205                 IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,      \
 206                           TRACE_GRAPH_ENT);             \
 207                 IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,      \
 208                           TRACE_GRAPH_RET);             \
 209                 IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
 210                 IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
 211                 IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,       \
 212                           TRACE_KMEM_ALLOC);    \
 213                 IF_ASSIGN(var, ent, struct kmemtrace_free_entry,        \
 214                           TRACE_KMEM_FREE);     \
 215                 __ftrace_bad_type();                                    \
 216         } while (0)
 217
 218 /*
 219  * An option specific to a tracer. This is a boolean value.
 220  * The bit is the bit index that sets its value on the
 221  * flags value in struct tracer_flags.
 222  */
 223 struct tracer_opt {
 224         const char      *name; /* Will appear on the trace_options file */
 225         u32             bit; /* Mask assigned in val field in tracer_flags */
 226 };
 227
 228 /*
 229  * The set of specific options for a tracer. Your tracer
 230  * have to set the initial value of the flags val.
 231  */
 232 struct tracer_flags {
 233         u32                     val;
 234         struct tracer_opt       *opts;
 235 };
 236
 237 /* Makes more easy to define a tracer opt */
 238 #define TRACER_OPT(s, b)        .name = #s, .bit = b
 239
 240
 241 /**
 242  * struct tracer - a specific tracer and its callbacks to interact with debugfs
 243  * @name: the name chosen to select it on the available_tracers file
 244  * @init: called when one switches to this tracer (echo name > current_tracer)
 245  * @reset: called when one switches to another tracer
 246  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
 247  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
 248  * @open: called when the trace file is opened
 249  * @pipe_open: called when the trace_pipe file is opened
 250  * @wait_pipe: override how the user waits for traces on trace_pipe
 251  * @close: called when the trace file is released
 252  * @read: override the default read callback on trace_pipe
 253  * @splice_read: override the default splice_read callback on trace_pipe
 254  * @selftest: selftest to run on boot (see trace_selftest.c)
 255  * @print_headers: override the first lines that describe your columns
 256  * @print_line: callback that prints a trace
 257  * @set_flag: signals one of your private flags changed (trace_options file)
 258  * @flags: your private flags
 259  */
 260 struct tracer {
 261         const char              *name;
 262         int                     (*init)(struct trace_array *tr);
 263         void                    (*reset)(struct trace_array *tr);
 264         void                    (*start)(struct trace_array *tr);
 265         void                    (*stop)(struct trace_array *tr);
 266         void                    (*open)(struct trace_iterator *iter);
 267         void                    (*pipe_open)(struct trace_iterator *iter);
 268         void                    (*wait_pipe)(struct trace_iterator *iter);
 269         void                    (*close)(struct trace_iterator *iter);
 270         ssize_t                 (*read)(struct trace_iterator *iter,
 271                                         struct file *filp, char __user *ubuf,
 272                                         size_t cnt, loff_t *ppos);
 273         ssize_t                 (*splice_read)(struct trace_iterator *iter,
 274                                                struct file *filp,
 275                                                loff_t *ppos,
 276                                                struct pipe_inode_info *pipe,
 277                                                size_t len,
 278                                                unsigned int flags);
 279 #ifdef CONFIG_FTRACE_STARTUP_TEST
 280         int                     (*selftest)(struct tracer *trace,
 281                                             struct trace_array *tr);
 282 #endif
 283         void                    (*print_header)(struct seq_file *m);
 284         enum print_line_t       (*print_line)(struct trace_iterator *iter);
 285         /* If you handled the flag setting, return 0 */
 286         int                     (*set_flag)(u32 old_flags, u32 bit, int set);
 287         struct tracer           *next;
 288         int                     print_max;
 289         struct tracer_flags     *flags;
 290 };
 291
 292
 293 #define TRACE_PIPE_ALL_CPU      -1
 294
 295 int tracer_init(struct tracer *t, struct trace_array *tr);
 296 int tracing_is_enabled(void);
 297 void trace_wake_up(void);
 298 void tracing_reset(struct trace_array *tr, int cpu);
 299 void tracing_reset_online_cpus(struct trace_array *tr);
 300 void tracing_reset_current(int cpu);
 301 void tracing_reset_current_online_cpus(void);
 302 int tracing_open_generic(struct inode *inode, struct file *filp);
 303 struct dentry *trace_create_file(const char *name,
 304                                  mode_t mode,
 305                                  struct dentry *parent,
 306                                  void *data,
 307                                  const struct file_operations *fops);
 308
 309 struct dentry *tracing_init_dentry(void);
 310 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
 311
 312 struct ring_buffer_event;
 313
 314 struct ring_buffer_event *
 315 trace_buffer_lock_reserve(struct ring_buffer *buffer,
 316                           int type,
 317                           unsigned long len,
 318                           unsigned long flags,
 319                           int pc);
 320 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
 321                                 struct ring_buffer_event *event,
 322                                 unsigned long flags, int pc);
 323
 324 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 325                                                 struct trace_array_cpu *data);
 326
 327 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 328                                           int *ent_cpu, u64 *ent_ts);
 329
 330 void default_wait_pipe(struct trace_iterator *iter);
 331 void poll_wait_pipe(struct trace_iterator *iter);
 332
 333 void ftrace(struct trace_array *tr,
 334                             struct trace_array_cpu *data,
 335                             unsigned long ip,
 336                             unsigned long parent_ip,
 337                             unsigned long flags, int pc);
 338 void tracing_sched_switch_trace(struct trace_array *tr,
 339                                 struct task_struct *prev,
 340                                 struct task_struct *next,
 341                                 unsigned long flags, int pc);
 342
 343 void tracing_sched_wakeup_trace(struct trace_array *tr,
 344                                 struct task_struct *wakee,
 345                                 struct task_struct *cur,
 346                                 unsigned long flags, int pc);
 347 void trace_special(struct trace_array *tr,
 348                    struct trace_array_cpu *data,
 349                    unsigned long arg1,
 350                    unsigned long arg2,
 351                    unsigned long arg3, int pc);
 352 void trace_function(struct trace_array *tr,
 353                     unsigned long ip,
 354                     unsigned long parent_ip,
 355                     unsigned long flags, int pc);
 356
 357 void trace_graph_return(struct ftrace_graph_ret *trace);
 358 int trace_graph_entry(struct ftrace_graph_ent *trace);
 359 void set_graph_array(struct trace_array *tr);
 360
 361 void tracing_start_cmdline_record(void);
 362 void tracing_stop_cmdline_record(void);
 363 void tracing_sched_switch_assign_trace(struct trace_array *tr);
 364 void tracing_stop_sched_switch_record(void);
 365 void tracing_start_sched_switch_record(void);
 366 int register_tracer(struct tracer *type);
 367 void unregister_tracer(struct tracer *type);
 368 int is_tracing_stopped(void);
 369
 370 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 371
 372 #ifdef CONFIG_TRACER_MAX_TRACE
 373 extern unsigned long tracing_max_latency;
 374 extern unsigned long tracing_thresh;
 375
 376 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
 377 void update_max_tr_single(struct trace_array *tr,
 378                           struct task_struct *tsk, int cpu);
 379 #endif /* CONFIG_TRACER_MAX_TRACE */
 380
 381 #ifdef CONFIG_STACKTRACE
 382 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
 383                         int skip, int pc);
 384
 385 void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
 386                             int pc);
 387
 388 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
 389                    int pc);
 390 #else
 391 static inline void ftrace_trace_stack(struct trace_array *tr,
 392                                       unsigned long flags, int skip, int pc)
 393 {
 394 }
 395
 396 static inline void ftrace_trace_userstack(struct trace_array *tr,
 397                                           unsigned long flags, int pc)
 398 {
 399 }
 400
 401 static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
 402                                  int skip, int pc)
 403 {
 404 }
 405 #endif /* CONFIG_STACKTRACE */
 406
 407 extern cycle_t ftrace_now(int cpu);
 408
 409 extern void trace_find_cmdline(int pid, char comm[]);
 410
 411 #ifdef CONFIG_DYNAMIC_FTRACE
 412 extern unsigned long ftrace_update_tot_cnt;
 413 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
 414 extern int DYN_FTRACE_TEST_NAME(void);
 415 #endif
 416
 417 extern int ring_buffer_expanded;
 418 extern bool tracing_selftest_disabled;
 419 DECLARE_PER_CPU(local_t, ftrace_cpu_disabled);
 420
 421 #ifdef CONFIG_FTRACE_STARTUP_TEST
 422 extern int trace_selftest_startup_function(struct tracer *trace,
 423                                            struct trace_array *tr);
 424 extern int trace_selftest_startup_function_graph(struct tracer *trace,
 425                                                  struct trace_array *tr);
 426 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
 427                                           struct trace_array *tr);
 428 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
 429                                              struct trace_array *tr);
 430 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
 431                                                  struct trace_array *tr);
 432 extern int trace_selftest_startup_wakeup(struct tracer *trace,
 433                                          struct trace_array *tr);
 434 extern int trace_selftest_startup_nop(struct tracer *trace,
 435                                          struct trace_array *tr);
 436 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
 437                                                struct trace_array *tr);
 438 extern int trace_selftest_startup_sysprof(struct tracer *trace,
 439                                                struct trace_array *tr);
 440 extern int trace_selftest_startup_branch(struct tracer *trace,
 441                                          struct trace_array *tr);
 442 extern int trace_selftest_startup_hw_branches(struct tracer *trace,
 443                                               struct trace_array *tr);
 444 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 445
 446 extern void *head_page(struct trace_array_cpu *data);
 447 extern unsigned long long ns2usecs(cycle_t nsec);
 448 extern int
 449 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
 450 extern int
 451 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
 452 extern int
 453 trace_array_vprintk(struct trace_array *tr,
 454                     unsigned long ip, const char *fmt, va_list args);
 455 int trace_array_printk(struct trace_array *tr,
 456                        unsigned long ip, const char *fmt, ...);
 457
 458 extern unsigned long trace_flags;
 459
 460 extern int trace_clock_id;
 461
 462 /* Standard output formatting function used for function return traces */
 463 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 464 extern enum print_line_t print_graph_function(struct trace_iterator *iter);
 465 extern enum print_line_t
 466 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
 467
 468 #ifdef CONFIG_DYNAMIC_FTRACE
 469 /* TODO: make this variable */
 470 #define FTRACE_GRAPH_MAX_FUNCS          32
 471 extern int ftrace_graph_count;
 472 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
 473
 474 static inline int ftrace_graph_addr(unsigned long addr)
 475 {
 476         int i;
 477
 478         if (!ftrace_graph_count || test_tsk_trace_graph(current))
 479                 return 1;
 480
 481         for (i = 0; i < ftrace_graph_count; i++) {
 482                 if (addr == ftrace_graph_funcs[i])
 483                         return 1;
 484         }
 485
 486         return 0;
 487 }
 488 #else
 489 static inline int ftrace_trace_addr(unsigned long addr)
 490 {
 491         return 1;
 492 }
 493 static inline int ftrace_graph_addr(unsigned long addr)
 494 {
 495         return 1;
 496 }
 497 #endif /* CONFIG_DYNAMIC_FTRACE */
 498 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
 499 static inline enum print_line_t
 500 print_graph_function(struct trace_iterator *iter)
 501 {
 502         return TRACE_TYPE_UNHANDLED;
 503 }
 504 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 505
 506 extern struct pid *ftrace_pid_trace;
 507
 508 #ifdef CONFIG_FUNCTION_TRACER
 509 static inline int ftrace_trace_task(struct task_struct *task)
 510 {
 511         if (!ftrace_pid_trace)
 512                 return 1;
 513
 514         return test_tsk_trace_trace(task);
 515 }
 516 #else
 517 static inline int ftrace_trace_task(struct task_struct *task)
 518 {
 519         return 1;
 520 }
 521 #endif
 522
 523 /*
 524  * struct trace_parser - servers for reading the user input separated by spaces
 525  * @cont: set if the input is not complete - no final space char was found
 526  * @buffer: holds the parsed user input
 527  * @idx: user input lenght
 528  * @size: buffer size
 529  */
 530 struct trace_parser {
 531         bool            cont;
 532         char            *buffer;
 533         unsigned        idx;
 534         unsigned        size;
 535 };
 536
 537 static inline bool trace_parser_loaded(struct trace_parser *parser)
 538 {
 539         return (parser->idx != 0);
 540 }
 541
 542 static inline bool trace_parser_cont(struct trace_parser *parser)
 543 {
 544         return parser->cont;
 545 }
 546
 547 static inline void trace_parser_clear(struct trace_parser *parser)
 548 {
 549         parser->cont = false;
 550         parser->idx = 0;
 551 }
 552
 553 extern int trace_parser_get_init(struct trace_parser *parser, int size);
 554 extern void trace_parser_put(struct trace_parser *parser);
 555 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 556         size_t cnt, loff_t *ppos);
 557
 558 /*
 559  * trace_iterator_flags is an enumeration that defines bit
 560  * positions into trace_flags that controls the output.
 561  *
 562  * NOTE: These bits must match the trace_options array in
 563  *       trace.c.
 564  */
 565 enum trace_iterator_flags {
 566         TRACE_ITER_PRINT_PARENT         = 0x01,
 567         TRACE_ITER_SYM_OFFSET           = 0x02,
 568         TRACE_ITER_SYM_ADDR             = 0x04,
 569         TRACE_ITER_VERBOSE              = 0x08,
 570         TRACE_ITER_RAW                  = 0x10,
 571         TRACE_ITER_HEX                  = 0x20,
 572         TRACE_ITER_BIN                  = 0x40,
 573         TRACE_ITER_BLOCK                = 0x80,
 574         TRACE_ITER_STACKTRACE           = 0x100,
 575         TRACE_ITER_SCHED_TREE           = 0x200,
 576         TRACE_ITER_PRINTK               = 0x400,
 577         TRACE_ITER_PREEMPTONLY          = 0x800,
 578         TRACE_ITER_BRANCH               = 0x1000,
 579         TRACE_ITER_ANNOTATE             = 0x2000,
 580         TRACE_ITER_USERSTACKTRACE       = 0x4000,
 581         TRACE_ITER_SYM_USEROBJ          = 0x8000,
 582         TRACE_ITER_PRINTK_MSGONLY       = 0x10000,
 583         TRACE_ITER_CONTEXT_INFO         = 0x20000, /* Print pid/cpu/time */
 584         TRACE_ITER_LATENCY_FMT          = 0x40000,
 585         TRACE_ITER_SLEEP_TIME           = 0x80000,
 586         TRACE_ITER_GRAPH_TIME           = 0x100000,
 587 };
 588
 589 /*
 590  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
 591  * control the output of kernel symbols.
 592  */
 593 #define TRACE_ITER_SYM_MASK \
 594         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
 595
 596 extern struct tracer nop_trace;
 597
 598 /**
 599  * ftrace_preempt_disable - disable preemption scheduler safe
 600  *
 601  * When tracing can happen inside the scheduler, there exists
 602  * cases that the tracing might happen before the need_resched
 603  * flag is checked. If this happens and the tracer calls
 604  * preempt_enable (after a disable), a schedule might take place
 605  * causing an infinite recursion.
 606  *
 607  * To prevent this, we read the need_resched flag before
 608  * disabling preemption. When we want to enable preemption we
 609  * check the flag, if it is set, then we call preempt_enable_no_resched.
 610  * Otherwise, we call preempt_enable.
 611  *
 612  * The rational for doing the above is that if need_resched is set
 613  * and we have yet to reschedule, we are either in an atomic location
 614  * (where we do not need to check for scheduling) or we are inside
 615  * the scheduler and do not want to resched.
 616  */
 617 static inline int ftrace_preempt_disable(void)
 618 {
 619         int resched;
 620
 621         resched = need_resched();
 622         preempt_disable_notrace();
 623
 624         return resched;
 625 }
 626
 627 /**
 628  * ftrace_preempt_enable - enable preemption scheduler safe
 629  * @resched: the return value from ftrace_preempt_disable
 630  *
 631  * This is a scheduler safe way to enable preemption and not miss
 632  * any preemption checks. The disabled saved the state of preemption.
 633  * If resched is set, then we are either inside an atomic or
 634  * are inside the scheduler (we would have already scheduled
 635  * otherwise). In this case, we do not want to call normal
 636  * preempt_enable, but preempt_enable_no_resched instead.
 637  */
 638 static inline void ftrace_preempt_enable(int resched)
 639 {
 640         if (resched)
 641                 preempt_enable_no_resched_notrace();
 642         else
 643                 preempt_enable_notrace();
 644 }
 645
 646 #ifdef CONFIG_BRANCH_TRACER
 647 extern int enable_branch_tracing(struct trace_array *tr);
 648 extern void disable_branch_tracing(void);
 649 static inline int trace_branch_enable(struct trace_array *tr)
 650 {
 651         if (trace_flags & TRACE_ITER_BRANCH)
 652                 return enable_branch_tracing(tr);
 653         return 0;
 654 }
 655 static inline void trace_branch_disable(void)
 656 {
 657         /* due to races, always disable */
 658         disable_branch_tracing();
 659 }
 660 #else
 661 static inline int trace_branch_enable(struct trace_array *tr)
 662 {
 663         return 0;
 664 }
 665 static inline void trace_branch_disable(void)
 666 {
 667 }
 668 #endif /* CONFIG_BRANCH_TRACER */
 669
 670 /* set ring buffers to default size if not already done so */
 671 int tracing_update_buffers(void);
 672
 673 /* trace event type bit fields, not numeric */
 674 enum {
 675         TRACE_EVENT_TYPE_PRINTF         = 1,
 676         TRACE_EVENT_TYPE_RAW            = 2,
 677 };
 678
 679 struct ftrace_event_field {
 680         struct list_head        link;
 681         char                    *name;
 682         char                    *type;
 683         int                     filter_type;
 684         int                     offset;
 685         int                     size;
 686         int                     is_signed;
 687 };
 688
 689 struct event_filter {
 690         int                     n_preds;
 691         struct filter_pred      **preds;
 692         char                    *filter_string;
 693         bool                    no_reset;
 694 };
 695
 696 struct event_subsystem {
 697         struct list_head        list;
 698         const char              *name;
 699         struct dentry           *entry;
 700         struct event_filter     *filter;
 701         int                     nr_events;
 702 };
 703
 704 struct filter_pred;
 705
 706 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
 707                                  int val1, int val2);
 708
 709 struct filter_pred {
 710         filter_pred_fn_t fn;
 711         u64 val;
 712         char str_val[MAX_FILTER_STR_VAL];
 713         int str_len;
 714         char *field_name;
 715         int offset;
 716         int not;
 717         int op;
 718         int pop_n;
 719 };
 720
 721 extern void print_event_filter(struct ftrace_event_call *call,
 722                                struct trace_seq *s);
 723 extern int apply_event_filter(struct ftrace_event_call *call,
 724                               char *filter_string);
 725 extern int apply_subsystem_event_filter(struct event_subsystem *system,
 726                                         char *filter_string);
 727 extern void print_subsystem_event_filter(struct event_subsystem *system,
 728                                          struct trace_seq *s);
 729 extern int filter_assign_type(const char *type);
 730
 731 static inline int
 732 filter_check_discard(struct ftrace_event_call *call, void *rec,
 733                      struct ring_buffer *buffer,
 734                      struct ring_buffer_event *event)
 735 {
 736         if (unlikely(call->filter_active) && !filter_match_preds(call, rec)) {
 737                 ring_buffer_discard_commit(buffer, event);
 738                 return 1;
 739         }
 740
 741         return 0;
 742 }
 743
 744 extern struct mutex event_mutex;
 745 extern struct list_head ftrace_events;
 746
 747 extern const char *__start___trace_bprintk_fmt[];
 748 extern const char *__stop___trace_bprintk_fmt[];
 749
 750 #undef FTRACE_ENTRY
 751 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print)             \
 752         extern struct ftrace_event_call event_##call;
 753 #undef FTRACE_ENTRY_DUP
 754 #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)         \
 755         FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
 756 #include "trace_entries.h"
 757
 758 #endif /* _LINUX_KERNEL_TRACE_H */