include/linux/ftrace_event.h

   1 #ifndef _LINUX_FTRACE_EVENT_H
   2 #define _LINUX_FTRACE_EVENT_H
   3
   4 #include <linux/ring_buffer.h>
   5 #include <linux/trace_seq.h>
   6 #include <linux/percpu.h>
   7 #include <linux/hardirq.h>
   8 #include <linux/perf_event.h>
   9
  10 struct trace_array;
  11 struct trace_buffer;
  12 struct tracer;
  13 struct dentry;
  14
  15 struct trace_print_flags {
  16         unsigned long           mask;
  17         const char              *name;
  18 };
  19
  20 struct trace_print_flags_u64 {
  21         unsigned long long      mask;
  22         const char              *name;
  23 };
  24
  25 const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
  26                                    unsigned long flags,
  27                                    const struct trace_print_flags *flag_array);
  28
  29 const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
  30                                      const struct trace_print_flags *symbol_array);
  31
  32 #if BITS_PER_LONG == 32
  33 const char *ftrace_print_symbols_seq_u64(struct trace_seq *p,
  34                                          unsigned long long val,
  35                                          const struct trace_print_flags_u64
  36                                                                  *symbol_array);
  37 #endif
  38
  39 const char *ftrace_print_hex_seq(struct trace_seq *p,
  40                                  const unsigned char *buf, int len);
  41
  42 struct trace_iterator;
  43 struct trace_event;
  44
  45 int ftrace_raw_output_prep(struct trace_iterator *iter,
  46                            struct trace_event *event);
  47
  48 /*
  49  * The trace entry - the most basic unit of tracing. This is what
  50  * is printed in the end as a single line in the trace output, such as:
  51  *
  52  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
  53  */
  54 struct trace_entry {
  55         unsigned short          type;
  56         unsigned char           flags;
  57         unsigned char           preempt_count;
  58         int                     pid;
  59 };
  60
  61 #define FTRACE_MAX_EVENT                                                \
  62         ((1 << (sizeof(((struct trace_entry *)0)->type) * 8)) - 1)
  63
  64 /*
  65  * Trace iterator - used by printout routines who present trace
  66  * results to users and which routines might sleep, etc:
  67  */
  68 struct trace_iterator {
  69         struct trace_array      *tr;
  70         struct tracer           *trace;
  71         struct trace_buffer     *trace_buffer;
  72         void                    *private;
  73         int                     cpu_file;
  74         struct mutex            mutex;
  75         struct ring_buffer_iter **buffer_iter;
  76         unsigned long           iter_flags;
  77
  78         /* trace_seq for __print_flags() and __print_symbolic() etc. */
  79         struct trace_seq        tmp_seq;
  80
  81         cpumask_var_t           started;
  82
  83         /* it's true when current open file is snapshot */
  84         bool                    snapshot;
  85
  86         /* The below is zeroed out in pipe_read */
  87         struct trace_seq        seq;
  88         struct trace_entry      *ent;
  89         unsigned long           lost_events;
  90         int                     leftover;
  91         int                     ent_size;
  92         int                     cpu;
  93         u64                     ts;
  94
  95         loff_t                  pos;
  96         long                    idx;
  97
  98         /* All new field here will be zeroed out in pipe_read */
  99 };
 100
 101 enum trace_iter_flags {
 102         TRACE_FILE_LAT_FMT      = 1,
 103         TRACE_FILE_ANNOTATE     = 2,
 104         TRACE_FILE_TIME_IN_NS   = 4,
 105 };
 106
 107
 108 typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
 109                                       int flags, struct trace_event *event);
 110
 111 struct trace_event_functions {
 112         trace_print_func        trace;
 113         trace_print_func        raw;
 114         trace_print_func        hex;
 115         trace_print_func        binary;
 116 };
 117
 118 struct trace_event {
 119         struct hlist_node               node;
 120         struct list_head                list;
 121         int                             type;
 122         struct trace_event_functions    *funcs;
 123 };
 124
 125 extern int register_ftrace_event(struct trace_event *event);
 126 extern int unregister_ftrace_event(struct trace_event *event);
 127
 128 /* Return values for print_line callback */
 129 enum print_line_t {
 130         TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
 131         TRACE_TYPE_HANDLED      = 1,
 132         TRACE_TYPE_UNHANDLED    = 2,    /* Relay to other output functions */
 133         TRACE_TYPE_NO_CONSUME   = 3     /* Handled but ask to not consume */
 134 };
 135
 136 void tracing_generic_entry_update(struct trace_entry *entry,
 137                                   unsigned long flags,
 138                                   int pc);
 139 struct ftrace_event_file;
 140
 141 struct ring_buffer_event *
 142 trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
 143                                 struct ftrace_event_file *ftrace_file,
 144                                 int type, unsigned long len,
 145                                 unsigned long flags, int pc);
 146 struct ring_buffer_event *
 147 trace_current_buffer_lock_reserve(struct ring_buffer **current_buffer,
 148                                   int type, unsigned long len,
 149                                   unsigned long flags, int pc);
 150 void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
 151                                         struct ring_buffer_event *event,
 152                                         unsigned long flags, int pc);
 153 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
 154                                 struct ring_buffer_event *event,
 155                                 unsigned long flags, int pc);
 156 void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer,
 157                                      struct ring_buffer_event *event,
 158                                      unsigned long flags, int pc,
 159                                      struct pt_regs *regs);
 160 void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
 161                                          struct ring_buffer_event *event);
 162
 163 void tracing_record_cmdline(struct task_struct *tsk);
 164
 165 struct event_filter;
 166
 167 enum trace_reg {
 168         TRACE_REG_REGISTER,
 169         TRACE_REG_UNREGISTER,
 170 #ifdef CONFIG_PERF_EVENTS
 171         TRACE_REG_PERF_REGISTER,
 172         TRACE_REG_PERF_UNREGISTER,
 173         TRACE_REG_PERF_OPEN,
 174         TRACE_REG_PERF_CLOSE,
 175         TRACE_REG_PERF_ADD,
 176         TRACE_REG_PERF_DEL,
 177 #endif
 178 };
 179
 180 struct ftrace_event_call;
 181
 182 struct ftrace_event_class {
 183         char                    *system;
 184         void                    *probe;
 185 #ifdef CONFIG_PERF_EVENTS
 186         void                    *perf_probe;
 187 #endif
 188         int                     (*reg)(struct ftrace_event_call *event,
 189                                        enum trace_reg type, void *data);
 190         int                     (*define_fields)(struct ftrace_event_call *);
 191         struct list_head        *(*get_fields)(struct ftrace_event_call *);
 192         struct list_head        fields;
 193         int                     (*raw_init)(struct ftrace_event_call *);
 194 };
 195
 196 extern int ftrace_event_reg(struct ftrace_event_call *event,
 197                             enum trace_reg type, void *data);
 198
 199 enum {
 200         TRACE_EVENT_FL_FILTERED_BIT,
 201         TRACE_EVENT_FL_CAP_ANY_BIT,
 202         TRACE_EVENT_FL_NO_SET_FILTER_BIT,
 203         TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
 204         TRACE_EVENT_FL_WAS_ENABLED_BIT,
 205         TRACE_EVENT_FL_USE_CALL_FILTER_BIT,
 206 };
 207
 208 /*
 209  * Event flags:
 210  *  FILTERED      - The event has a filter attached
 211  *  CAP_ANY       - Any user can enable for perf
 212  *  NO_SET_FILTER - Set when filter has error and is to be ignored
 213  *  IGNORE_ENABLE - For ftrace internal events, do not enable with debugfs file
 214  *  WAS_ENABLED   - Set and stays set when an event was ever enabled
 215  *                    (used for module unloading, if a module event is enabled,
 216  *                     it is best to clear the buffers that used it).
 217  *  USE_CALL_FILTER - For ftrace internal events, don't use file filter
 218  */
 219 enum {
 220         TRACE_EVENT_FL_FILTERED         = (1 << TRACE_EVENT_FL_FILTERED_BIT),
 221         TRACE_EVENT_FL_CAP_ANY          = (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
 222         TRACE_EVENT_FL_NO_SET_FILTER    = (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
 223         TRACE_EVENT_FL_IGNORE_ENABLE    = (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
 224         TRACE_EVENT_FL_WAS_ENABLED      = (1 << TRACE_EVENT_FL_WAS_ENABLED_BIT),
 225         TRACE_EVENT_FL_USE_CALL_FILTER  = (1 << TRACE_EVENT_FL_USE_CALL_FILTER_BIT),
 226 };
 227
 228 struct ftrace_event_call {
 229         struct list_head        list;
 230         struct ftrace_event_class *class;
 231         char                    *name;
 232         struct trace_event      event;
 233         const char              *print_fmt;
 234         struct event_filter     *filter;
 235         struct list_head        *files;
 236         void                    *mod;
 237         void                    *data;
 238         /*
 239          *   bit 0:             filter_active
 240          *   bit 1:             allow trace by non root (cap any)
 241          *   bit 2:             failed to apply filter
 242          *   bit 3:             ftrace internal event (do not enable)
 243          *   bit 4:             Event was enabled by module
 244          *   bit 5:             use call filter rather than file filter
 245          */
 246         int                     flags; /* static flags of different events */
 247
 248 #ifdef CONFIG_PERF_EVENTS
 249         int                             perf_refcount;
 250         struct hlist_head __percpu      *perf_events;
 251
 252         int     (*perf_perm)(struct ftrace_event_call *,
 253                              struct perf_event *);
 254 #endif
 255 };
 256
 257 struct trace_array;
 258 struct ftrace_subsystem_dir;
 259
 260 enum {
 261         FTRACE_EVENT_FL_ENABLED_BIT,
 262         FTRACE_EVENT_FL_RECORDED_CMD_BIT,
 263         FTRACE_EVENT_FL_FILTERED_BIT,
 264         FTRACE_EVENT_FL_NO_SET_FILTER_BIT,
 265         FTRACE_EVENT_FL_SOFT_MODE_BIT,
 266         FTRACE_EVENT_FL_SOFT_DISABLED_BIT,
 267 };
 268
 269 /*
 270  * Ftrace event file flags:
 271  *  ENABLED       - The event is enabled
 272  *  RECORDED_CMD  - The comms should be recorded at sched_switch
 273  *  FILTERED      - The event has a filter attached
 274  *  NO_SET_FILTER - Set when filter has error and is to be ignored
 275  *  SOFT_MODE     - The event is enabled/disabled by SOFT_DISABLED
 276  *  SOFT_DISABLED - When set, do not trace the event (even though its
 277  *                   tracepoint may be enabled)
 278  */
 279 enum {
 280         FTRACE_EVENT_FL_ENABLED         = (1 << FTRACE_EVENT_FL_ENABLED_BIT),
 281         FTRACE_EVENT_FL_RECORDED_CMD    = (1 << FTRACE_EVENT_FL_RECORDED_CMD_BIT),
 282         FTRACE_EVENT_FL_FILTERED        = (1 << FTRACE_EVENT_FL_FILTERED_BIT),
 283         FTRACE_EVENT_FL_NO_SET_FILTER   = (1 << FTRACE_EVENT_FL_NO_SET_FILTER_BIT),
 284         FTRACE_EVENT_FL_SOFT_MODE       = (1 << FTRACE_EVENT_FL_SOFT_MODE_BIT),
 285         FTRACE_EVENT_FL_SOFT_DISABLED   = (1 << FTRACE_EVENT_FL_SOFT_DISABLED_BIT),
 286 };
 287
 288 struct ftrace_event_file {
 289         struct list_head                list;
 290         struct ftrace_event_call        *event_call;
 291         struct event_filter             *filter;
 292         struct dentry                   *dir;
 293         struct trace_array              *tr;
 294         struct ftrace_subsystem_dir     *system;
 295
 296         /*
 297          * 32 bit flags:
 298          *   bit 0:             enabled
 299          *   bit 1:             enabled cmd record
 300          *   bit 2:             enable/disable with the soft disable bit
 301          *   bit 3:             soft disabled
 302          *
 303          * Note: The bits must be set atomically to prevent races
 304          * from other writers. Reads of flags do not need to be in
 305          * sync as they occur in critical sections. But the way flags
 306          * is currently used, these changes do not affect the code
 307          * except that when a change is made, it may have a slight
 308          * delay in propagating the changes to other CPUs due to
 309          * caching and such. Which is mostly OK ;-)
 310          */
 311         unsigned long           flags;
 312         atomic_t                sm_ref; /* soft-mode reference counter */
 313 };
 314
 315 #define __TRACE_EVENT_FLAGS(name, value)                                \
 316         static int __init trace_init_flags_##name(void)                 \
 317         {                                                               \
 318                 event_##name.flags = value;                             \
 319                 return 0;                                               \
 320         }                                                               \
 321         early_initcall(trace_init_flags_##name);
 322
 323 #define __TRACE_EVENT_PERF_PERM(name, expr...)                          \
 324         static int perf_perm_##name(struct ftrace_event_call *tp_event, \
 325                                     struct perf_event *p_event)         \
 326         {                                                               \
 327                 return ({ expr; });                                     \
 328         }                                                               \
 329         static int __init trace_init_perf_perm_##name(void)             \
 330         {                                                               \
 331                 event_##name.perf_perm = &perf_perm_##name;             \
 332                 return 0;                                               \
 333         }                                                               \
 334         early_initcall(trace_init_perf_perm_##name);
 335
 336 #define PERF_MAX_TRACE_SIZE     2048
 337
 338 #define MAX_FILTER_STR_VAL      256     /* Should handle KSYM_SYMBOL_LEN */
 339
 340 extern void destroy_preds(struct ftrace_event_file *file);
 341 extern void destroy_call_preds(struct ftrace_event_call *call);
 342 extern int filter_match_preds(struct event_filter *filter, void *rec);
 343
 344 extern int filter_check_discard(struct ftrace_event_file *file, void *rec,
 345                                 struct ring_buffer *buffer,
 346                                 struct ring_buffer_event *event);
 347 extern int call_filter_check_discard(struct ftrace_event_call *call, void *rec,
 348                                      struct ring_buffer *buffer,
 349                                      struct ring_buffer_event *event);
 350
 351 enum {
 352         FILTER_OTHER = 0,
 353         FILTER_STATIC_STRING,
 354         FILTER_DYN_STRING,
 355         FILTER_PTR_STRING,
 356         FILTER_TRACE_FN,
 357 };
 358
 359 #define EVENT_STORAGE_SIZE 128
 360 extern struct mutex event_storage_mutex;
 361 extern char event_storage[EVENT_STORAGE_SIZE];
 362
 363 extern int trace_event_raw_init(struct ftrace_event_call *call);
 364 extern int trace_define_field(struct ftrace_event_call *call, const char *type,
 365                               const char *name, int offset, int size,
 366                               int is_signed, int filter_type);
 367 extern int trace_add_event_call(struct ftrace_event_call *call);
 368 extern int trace_remove_event_call(struct ftrace_event_call *call);
 369
 370 #define is_signed_type(type)    (((type)(-1)) < (type)1)
 371
 372 int trace_set_clr_event(const char *system, const char *event, int set);
 373
 374 /*
 375  * The double __builtin_constant_p is because gcc will give us an error
 376  * if we try to allocate the static variable to fmt if it is not a
 377  * constant. Even with the outer if statement optimizing out.
 378  */
 379 #define event_trace_printk(ip, fmt, args...)                            \
 380 do {                                                                    \
 381         __trace_printk_check_format(fmt, ##args);                       \
 382         tracing_record_cmdline(current);                                \
 383         if (__builtin_constant_p(fmt)) {                                \
 384                 static const char *trace_printk_fmt                     \
 385                   __attribute__((section("__trace_printk_fmt"))) =      \
 386                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 387                                                                         \
 388                 __trace_bprintk(ip, trace_printk_fmt, ##args);          \
 389         } else                                                          \
 390                 __trace_printk(ip, fmt, ##args);                        \
 391 } while (0)
 392
 393 /**
 394  * tracepoint_string - register constant persistent string to trace system
 395  * @str - a constant persistent string that will be referenced in tracepoints
 396  *
 397  * If constant strings are being used in tracepoints, it is faster and
 398  * more efficient to just save the pointer to the string and reference
 399  * that with a printf "%s" instead of saving the string in the ring buffer
 400  * and wasting space and time.
 401  *
 402  * The problem with the above approach is that userspace tools that read
 403  * the binary output of the trace buffers do not have access to the string.
 404  * Instead they just show the address of the string which is not very
 405  * useful to users.
 406  *
 407  * With tracepoint_string(), the string will be registered to the tracing
 408  * system and exported to userspace via the debugfs/tracing/printk_formats
 409  * file that maps the string address to the string text. This way userspace
 410  * tools that read the binary buffers have a way to map the pointers to
 411  * the ASCII strings they represent.
 412  *
 413  * The @str used must be a constant string and persistent as it would not
 414  * make sense to show a string that no longer exists. But it is still fine
 415  * to be used with modules, because when modules are unloaded, if they
 416  * had tracepoints, the ring buffers are cleared too. As long as the string
 417  * does not change during the life of the module, it is fine to use
 418  * tracepoint_string() within a module.
 419  */
 420 #define tracepoint_string(str)                                          \
 421         ({                                                              \
 422                 static const char *___tp_str __tracepoint_string = str; \
 423                 ___tp_str;                                              \
 424         })
 425 #define __tracepoint_string     __attribute__((section("__tracepoint_str")))
 426
 427 #ifdef CONFIG_PERF_EVENTS
 428 struct perf_event;
 429
 430 DECLARE_PER_CPU(struct pt_regs, perf_trace_regs);
 431
 432 extern int  perf_trace_init(struct perf_event *event);
 433 extern void perf_trace_destroy(struct perf_event *event);
 434 extern int  perf_trace_add(struct perf_event *event, int flags);
 435 extern void perf_trace_del(struct perf_event *event, int flags);
 436 extern int  ftrace_profile_set_filter(struct perf_event *event, int event_id,
 437                                      char *filter_str);
 438 extern void ftrace_profile_free_filter(struct perf_event *event);
 439 extern void *perf_trace_buf_prepare(int size, unsigned short type,
 440                                     struct pt_regs *regs, int *rctxp);
 441
 442 static inline void
 443 perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
 444                        u64 count, struct pt_regs *regs, void *head,
 445                        struct task_struct *task)
 446 {
 447         perf_tp_event(addr, count, raw_data, size, regs, head, rctx, task);
 448 }
 449 #endif
 450
 451 #endif /* _LINUX_FTRACE_EVENT_H */