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