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
  12 enum trace_type {
  13         __TRACE_FIRST_TYPE = 0,
  14
  15         TRACE_FN,
  16         TRACE_CTX,
  17         TRACE_WAKE,
  18         TRACE_CONT,
  19         TRACE_STACK,
  20         TRACE_PRINT,
  21         TRACE_SPECIAL,
  22         TRACE_MMIO_RW,
  23         TRACE_MMIO_MAP,
  24         TRACE_BOOT,
  25         TRACE_FN_RET,
  26
  27         __TRACE_LAST_TYPE
  28 };
  29
  30 /*
  31  * The trace entry - the most basic unit of tracing. This is what
  32  * is printed in the end as a single line in the trace output, such as:
  33  *
  34  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
  35  */
  36 struct trace_entry {
  37         unsigned char           type;
  38         unsigned char           cpu;
  39         unsigned char           flags;
  40         unsigned char           preempt_count;
  41         int                     pid;
  42 };
  43
  44 /*
  45  * Function trace entry - function address and parent function addres:
  46  */
  47 struct ftrace_entry {
  48         struct trace_entry      ent;
  49         unsigned long           ip;
  50         unsigned long           parent_ip;
  51 };
  52
  53 /* Function return entry */
  54 struct ftrace_ret_entry {
  55         struct trace_entry      ent;
  56         unsigned long           ip;
  57         unsigned long           parent_ip;
  58         unsigned long long      calltime;
  59         unsigned long long      rettime;
  60 };
  61 extern struct tracer boot_tracer;
  62
  63 /*
  64  * Context switch trace entry - which task (and prio) we switched from/to:
  65  */
  66 struct ctx_switch_entry {
  67         struct trace_entry      ent;
  68         unsigned int            prev_pid;
  69         unsigned char           prev_prio;
  70         unsigned char           prev_state;
  71         unsigned int            next_pid;
  72         unsigned char           next_prio;
  73         unsigned char           next_state;
  74         unsigned int            next_cpu;
  75 };
  76
  77 /*
  78  * Special (free-form) trace entry:
  79  */
  80 struct special_entry {
  81         struct trace_entry      ent;
  82         unsigned long           arg1;
  83         unsigned long           arg2;
  84         unsigned long           arg3;
  85 };
  86
  87 /*
  88  * Stack-trace entry:
  89  */
  90
  91 #define FTRACE_STACK_ENTRIES    8
  92
  93 struct stack_entry {
  94         struct trace_entry      ent;
  95         unsigned long           caller[FTRACE_STACK_ENTRIES];
  96 };
  97
  98 /*
  99  * ftrace_printk entry:
 100  */
 101 struct print_entry {
 102         struct trace_entry      ent;
 103         unsigned long           ip;
 104         char                    buf[];
 105 };
 106
 107 #define TRACE_OLD_SIZE          88
 108
 109 struct trace_field_cont {
 110         unsigned char           type;
 111         /* Temporary till we get rid of this completely */
 112         char                    buf[TRACE_OLD_SIZE - 1];
 113 };
 114
 115 struct trace_mmiotrace_rw {
 116         struct trace_entry      ent;
 117         struct mmiotrace_rw     rw;
 118 };
 119
 120 struct trace_mmiotrace_map {
 121         struct trace_entry      ent;
 122         struct mmiotrace_map    map;
 123 };
 124
 125 struct trace_boot {
 126         struct trace_entry      ent;
 127         struct boot_trace       initcall;
 128 };
 129
 130 /*
 131  * trace_flag_type is an enumeration that holds different
 132  * states when a trace occurs. These are:
 133  *  IRQS_OFF            - interrupts were disabled
 134  *  IRQS_NOSUPPORT      - arch does not support irqs_disabled_flags
 135  *  NEED_RESCED         - reschedule is requested
 136  *  HARDIRQ             - inside an interrupt handler
 137  *  SOFTIRQ             - inside a softirq handler
 138  *  CONT                - multiple entries hold the trace item
 139  */
 140 enum trace_flag_type {
 141         TRACE_FLAG_IRQS_OFF             = 0x01,
 142         TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
 143         TRACE_FLAG_NEED_RESCHED         = 0x04,
 144         TRACE_FLAG_HARDIRQ              = 0x08,
 145         TRACE_FLAG_SOFTIRQ              = 0x10,
 146         TRACE_FLAG_CONT                 = 0x20,
 147 };
 148
 149 #define TRACE_BUF_SIZE          1024
 150
 151 /*
 152  * The CPU trace array - it consists of thousands of trace entries
 153  * plus some other descriptor data: (for example which task started
 154  * the trace, etc.)
 155  */
 156 struct trace_array_cpu {
 157         atomic_t                disabled;
 158
 159         /* these fields get copied into max-trace: */
 160         unsigned long           trace_idx;
 161         unsigned long           overrun;
 162         unsigned long           saved_latency;
 163         unsigned long           critical_start;
 164         unsigned long           critical_end;
 165         unsigned long           critical_sequence;
 166         unsigned long           nice;
 167         unsigned long           policy;
 168         unsigned long           rt_priority;
 169         cycle_t                 preempt_timestamp;
 170         pid_t                   pid;
 171         uid_t                   uid;
 172         char                    comm[TASK_COMM_LEN];
 173 };
 174
 175 struct trace_iterator;
 176
 177 /*
 178  * The trace array - an array of per-CPU trace arrays. This is the
 179  * highest level data structure that individual tracers deal with.
 180  * They have on/off state as well:
 181  */
 182 struct trace_array {
 183         struct ring_buffer      *buffer;
 184         unsigned long           entries;
 185         int                     cpu;
 186         cycle_t                 time_start;
 187         struct task_struct      *waiter;
 188         struct trace_array_cpu  *data[NR_CPUS];
 189 };
 190
 191 #define FTRACE_CMP_TYPE(var, type) \
 192         __builtin_types_compatible_p(typeof(var), type *)
 193
 194 #undef IF_ASSIGN
 195 #define IF_ASSIGN(var, entry, etype, id)                \
 196         if (FTRACE_CMP_TYPE(var, etype)) {              \
 197                 var = (typeof(var))(entry);             \
 198                 WARN_ON(id && (entry)->type != id);     \
 199                 break;                                  \
 200         }
 201
 202 /* Will cause compile errors if type is not found. */
 203 extern void __ftrace_bad_type(void);
 204
 205 /*
 206  * The trace_assign_type is a verifier that the entry type is
 207  * the same as the type being assigned. To add new types simply
 208  * add a line with the following format:
 209  *
 210  * IF_ASSIGN(var, ent, type, id);
 211  *
 212  *  Where "type" is the trace type that includes the trace_entry
 213  *  as the "ent" item. And "id" is the trace identifier that is
 214  *  used in the trace_type enum.
 215  *
 216  *  If the type can have more than one id, then use zero.
 217  */
 218 #define trace_assign_type(var, ent)                                     \
 219         do {                                                            \
 220                 IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);     \
 221                 IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);        \
 222                 IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \
 223                 IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
 224                 IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
 225                 IF_ASSIGN(var, ent, struct special_entry, 0);           \
 226                 IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
 227                           TRACE_MMIO_RW);                               \
 228                 IF_ASSIGN(var, ent, struct trace_mmiotrace_map,         \
 229                           TRACE_MMIO_MAP);                              \
 230                 IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT);     \
 231                 IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET); \
 232                 __ftrace_bad_type();                                    \
 233         } while (0)
 234
 235 /* Return values for print_line callback */
 236 enum print_line_t {
 237         TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
 238         TRACE_TYPE_HANDLED      = 1,
 239         TRACE_TYPE_UNHANDLED    = 2     /* Relay to other output functions */
 240 };
 241
 242 /*
 243  * A specific tracer, represented by methods that operate on a trace array:
 244  */
 245 struct tracer {
 246         const char              *name;
 247         void                    (*init)(struct trace_array *tr);
 248         void                    (*reset)(struct trace_array *tr);
 249         void                    (*start)(struct trace_array *tr);
 250         void                    (*stop)(struct trace_array *tr);
 251         void                    (*open)(struct trace_iterator *iter);
 252         void                    (*pipe_open)(struct trace_iterator *iter);
 253         void                    (*close)(struct trace_iterator *iter);
 254         ssize_t                 (*read)(struct trace_iterator *iter,
 255                                         struct file *filp, char __user *ubuf,
 256                                         size_t cnt, loff_t *ppos);
 257 #ifdef CONFIG_FTRACE_STARTUP_TEST
 258         int                     (*selftest)(struct tracer *trace,
 259                                             struct trace_array *tr);
 260 #endif
 261         enum print_line_t       (*print_line)(struct trace_iterator *iter);
 262         struct tracer           *next;
 263         int                     print_max;
 264 };
 265
 266 struct trace_seq {
 267         unsigned char           buffer[PAGE_SIZE];
 268         unsigned int            len;
 269         unsigned int            readpos;
 270 };
 271
 272 /*
 273  * Trace iterator - used by printout routines who present trace
 274  * results to users and which routines might sleep, etc:
 275  */
 276 struct trace_iterator {
 277         struct trace_array      *tr;
 278         struct tracer           *trace;
 279         void                    *private;
 280         struct ring_buffer_iter *buffer_iter[NR_CPUS];
 281
 282         /* The below is zeroed out in pipe_read */
 283         struct trace_seq        seq;
 284         struct trace_entry      *ent;
 285         int                     cpu;
 286         u64                     ts;
 287
 288         unsigned long           iter_flags;
 289         loff_t                  pos;
 290         long                    idx;
 291
 292         cpumask_t               started;
 293 };
 294
 295 int tracing_is_enabled(void);
 296 void trace_wake_up(void);
 297 void tracing_reset(struct trace_array *tr, int cpu);
 298 int tracing_open_generic(struct inode *inode, struct file *filp);
 299 struct dentry *tracing_init_dentry(void);
 300 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
 301
 302 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 303                                                 struct trace_array_cpu *data);
 304 void tracing_generic_entry_update(struct trace_entry *entry,
 305                                   unsigned long flags,
 306                                   int pc);
 307
 308 void ftrace(struct trace_array *tr,
 309                             struct trace_array_cpu *data,
 310                             unsigned long ip,
 311                             unsigned long parent_ip,
 312                             unsigned long flags, int pc);
 313 void tracing_sched_switch_trace(struct trace_array *tr,
 314                                 struct trace_array_cpu *data,
 315                                 struct task_struct *prev,
 316                                 struct task_struct *next,
 317                                 unsigned long flags, int pc);
 318 void tracing_record_cmdline(struct task_struct *tsk);
 319
 320 void tracing_sched_wakeup_trace(struct trace_array *tr,
 321                                 struct trace_array_cpu *data,
 322                                 struct task_struct *wakee,
 323                                 struct task_struct *cur,
 324                                 unsigned long flags, int pc);
 325 void trace_special(struct trace_array *tr,
 326                    struct trace_array_cpu *data,
 327                    unsigned long arg1,
 328                    unsigned long arg2,
 329                    unsigned long arg3, int pc);
 330 void trace_function(struct trace_array *tr,
 331                     struct trace_array_cpu *data,
 332                     unsigned long ip,
 333                     unsigned long parent_ip,
 334                     unsigned long flags, int pc);
 335 void
 336 trace_function_return(struct ftrace_retfunc *trace);
 337
 338 void tracing_start_cmdline_record(void);
 339 void tracing_stop_cmdline_record(void);
 340 void tracing_sched_switch_assign_trace(struct trace_array *tr);
 341 void tracing_stop_sched_switch_record(void);
 342 void tracing_start_sched_switch_record(void);
 343 int register_tracer(struct tracer *type);
 344 void unregister_tracer(struct tracer *type);
 345
 346 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 347
 348 extern unsigned long tracing_max_latency;
 349 extern unsigned long tracing_thresh;
 350
 351 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
 352 void update_max_tr_single(struct trace_array *tr,
 353                           struct task_struct *tsk, int cpu);
 354
 355 extern cycle_t ftrace_now(int cpu);
 356
 357 #ifdef CONFIG_FUNCTION_TRACER
 358 void tracing_start_function_trace(void);
 359 void tracing_stop_function_trace(void);
 360 #else
 361 # define tracing_start_function_trace()         do { } while (0)
 362 # define tracing_stop_function_trace()          do { } while (0)
 363 #endif
 364
 365 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
 366 typedef void
 367 (*tracer_switch_func_t)(void *private,
 368                         void *__rq,
 369                         struct task_struct *prev,
 370                         struct task_struct *next);
 371
 372 struct tracer_switch_ops {
 373         tracer_switch_func_t            func;
 374         void                            *private;
 375         struct tracer_switch_ops        *next;
 376 };
 377
 378 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
 379
 380 #ifdef CONFIG_DYNAMIC_FTRACE
 381 extern unsigned long ftrace_update_tot_cnt;
 382 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
 383 extern int DYN_FTRACE_TEST_NAME(void);
 384 #endif
 385
 386 #ifdef CONFIG_FTRACE_STARTUP_TEST
 387 extern int trace_selftest_startup_function(struct tracer *trace,
 388                                            struct trace_array *tr);
 389 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
 390                                           struct trace_array *tr);
 391 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
 392                                              struct trace_array *tr);
 393 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
 394                                                  struct trace_array *tr);
 395 extern int trace_selftest_startup_wakeup(struct tracer *trace,
 396                                          struct trace_array *tr);
 397 extern int trace_selftest_startup_nop(struct tracer *trace,
 398                                          struct trace_array *tr);
 399 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
 400                                                struct trace_array *tr);
 401 extern int trace_selftest_startup_sysprof(struct tracer *trace,
 402                                                struct trace_array *tr);
 403 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 404
 405 extern void *head_page(struct trace_array_cpu *data);
 406 extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
 407 extern void trace_seq_print_cont(struct trace_seq *s,
 408                                  struct trace_iterator *iter);
 409
 410 extern int
 411 seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
 412                 unsigned long sym_flags);
 413 extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 414                                  size_t cnt);
 415 extern long ns2usecs(cycle_t nsec);
 416 extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
 417
 418 extern unsigned long trace_flags;
 419
 420 /* Standard output formatting function used for function return traces */
 421 #ifdef CONFIG_FUNCTION_RET_TRACER
 422 extern enum print_line_t print_return_function(struct trace_iterator *iter);
 423 #else
 424 static inline enum print_line_t
 425 print_return_function(struct trace_iterator *iter)
 426 {
 427         return TRACE_TYPE_UNHANDLED;
 428 }
 429 #endif
 430
 431 /*
 432  * trace_iterator_flags is an enumeration that defines bit
 433  * positions into trace_flags that controls the output.
 434  *
 435  * NOTE: These bits must match the trace_options array in
 436  *       trace.c.
 437  */
 438 enum trace_iterator_flags {
 439         TRACE_ITER_PRINT_PARENT         = 0x01,
 440         TRACE_ITER_SYM_OFFSET           = 0x02,
 441         TRACE_ITER_SYM_ADDR             = 0x04,
 442         TRACE_ITER_VERBOSE              = 0x08,
 443         TRACE_ITER_RAW                  = 0x10,
 444         TRACE_ITER_HEX                  = 0x20,
 445         TRACE_ITER_BIN                  = 0x40,
 446         TRACE_ITER_BLOCK                = 0x80,
 447         TRACE_ITER_STACKTRACE           = 0x100,
 448         TRACE_ITER_SCHED_TREE           = 0x200,
 449         TRACE_ITER_PRINTK               = 0x400,
 450         TRACE_ITER_PREEMPTONLY          = 0x800,
 451 };
 452
 453 /*
 454  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
 455  * control the output of kernel symbols.
 456  */
 457 #define TRACE_ITER_SYM_MASK \
 458         (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
 459
 460 extern struct tracer nop_trace;
 461
 462 /**
 463  * ftrace_preempt_disable - disable preemption scheduler safe
 464  *
 465  * When tracing can happen inside the scheduler, there exists
 466  * cases that the tracing might happen before the need_resched
 467  * flag is checked. If this happens and the tracer calls
 468  * preempt_enable (after a disable), a schedule might take place
 469  * causing an infinite recursion.
 470  *
 471  * To prevent this, we read the need_recshed flag before
 472  * disabling preemption. When we want to enable preemption we
 473  * check the flag, if it is set, then we call preempt_enable_no_resched.
 474  * Otherwise, we call preempt_enable.
 475  *
 476  * The rational for doing the above is that if need resched is set
 477  * and we have yet to reschedule, we are either in an atomic location
 478  * (where we do not need to check for scheduling) or we are inside
 479  * the scheduler and do not want to resched.
 480  */
 481 static inline int ftrace_preempt_disable(void)
 482 {
 483         int resched;
 484
 485         resched = need_resched();
 486         preempt_disable_notrace();
 487
 488         return resched;
 489 }
 490
 491 /**
 492  * ftrace_preempt_enable - enable preemption scheduler safe
 493  * @resched: the return value from ftrace_preempt_disable
 494  *
 495  * This is a scheduler safe way to enable preemption and not miss
 496  * any preemption checks. The disabled saved the state of preemption.
 497  * If resched is set, then we were either inside an atomic or
 498  * are inside the scheduler (we would have already scheduled
 499  * otherwise). In this case, we do not want to call normal
 500  * preempt_enable, but preempt_enable_no_resched instead.
 501  */
 502 static inline void ftrace_preempt_enable(int resched)
 503 {
 504         if (resched)
 505                 preempt_enable_no_resched_notrace();
 506         else
 507                 preempt_enable_notrace();
 508 }
 509
 510 #endif /* _LINUX_KERNEL_TRACE_H */