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