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