include/linux/ftrace_event.h

   1 #ifndef _LINUX_FTRACE_EVENT_H
   2 #define _LINUX_FTRACE_EVENT_H
   3
   4 #include <linux/trace_seq.h>
   5 #include <linux/ring_buffer.h>
   6
   7
   8 struct trace_array;
   9 struct tracer;
  10 struct dentry;
  11
  12 /*
  13  * The trace entry - the most basic unit of tracing. This is what
  14  * is printed in the end as a single line in the trace output, such as:
  15  *
  16  *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
  17  */
  18 struct trace_entry {
  19         unsigned short          type;
  20         unsigned char           flags;
  21         unsigned char           preempt_count;
  22         int                     pid;
  23         int                     tgid;
  24 };
  25
  26 #define FTRACE_MAX_EVENT                                                \
  27         ((1 << (sizeof(((struct trace_entry *)0)->type) * 8)) - 1)
  28
  29 /*
  30  * Trace iterator - used by printout routines who present trace
  31  * results to users and which routines might sleep, etc:
  32  */
  33 struct trace_iterator {
  34         struct trace_array      *tr;
  35         struct tracer           *trace;
  36         void                    *private;
  37         int                     cpu_file;
  38         struct mutex            mutex;
  39         struct ring_buffer_iter *buffer_iter[NR_CPUS];
  40
  41         /* The below is zeroed out in pipe_read */
  42         struct trace_seq        seq;
  43         struct trace_entry      *ent;
  44         int                     cpu;
  45         u64                     ts;
  46
  47         unsigned long           iter_flags;
  48         loff_t                  pos;
  49         long                    idx;
  50
  51         cpumask_var_t           started;
  52 };
  53
  54
  55 typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
  56                                               int flags);
  57 struct trace_event {
  58         struct hlist_node       node;
  59         int                     type;
  60         trace_print_func        trace;
  61         trace_print_func        raw;
  62         trace_print_func        hex;
  63         trace_print_func        binary;
  64 };
  65
  66 extern int register_ftrace_event(struct trace_event *event);
  67 extern int unregister_ftrace_event(struct trace_event *event);
  68
  69 /* Return values for print_line callback */
  70 enum print_line_t {
  71         TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
  72         TRACE_TYPE_HANDLED      = 1,
  73         TRACE_TYPE_UNHANDLED    = 2,    /* Relay to other output functions */
  74         TRACE_TYPE_NO_CONSUME   = 3     /* Handled but ask to not consume */
  75 };
  76
  77
  78 struct ring_buffer_event *
  79 trace_current_buffer_lock_reserve(int type, unsigned long len,
  80                                   unsigned long flags, int pc);
  81 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
  82                                         unsigned long flags, int pc);
  83 void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event,
  84                                         unsigned long flags, int pc);
  85 void trace_current_buffer_discard_commit(struct ring_buffer_event *event);
  86
  87 void tracing_record_cmdline(struct task_struct *tsk);
  88
  89 struct ftrace_event_call {
  90         struct list_head        list;
  91         char                    *name;
  92         char                    *system;
  93         struct dentry           *dir;
  94         struct trace_event      *event;
  95         int                     enabled;
  96         int                     (*regfunc)(void);
  97         void                    (*unregfunc)(void);
  98         int                     id;
  99         int                     (*raw_init)(void);
 100         int                     (*show_format)(struct trace_seq *s);
 101         int                     (*define_fields)(void);
 102         struct list_head        fields;
 103         int                     n_preds;
 104         struct filter_pred      **preds;
 105         void                    *mod;
 106
 107 #ifdef CONFIG_EVENT_PROFILE
 108         atomic_t        profile_count;
 109         int             (*profile_enable)(struct ftrace_event_call *);
 110         void            (*profile_disable)(struct ftrace_event_call *);
 111 #endif
 112 };
 113
 114 #define MAX_FILTER_PRED         8
 115 #define MAX_FILTER_STR_VAL      128
 116
 117 extern int init_preds(struct ftrace_event_call *call);
 118 extern int filter_match_preds(struct ftrace_event_call *call, void *rec);
 119 extern int filter_current_check_discard(struct ftrace_event_call *call,
 120                                         void *rec,
 121                                         struct ring_buffer_event *event);
 122
 123 extern int trace_define_field(struct ftrace_event_call *call, char *type,
 124                               char *name, int offset, int size);
 125
 126
 127 /*
 128  * The double __builtin_constant_p is because gcc will give us an error
 129  * if we try to allocate the static variable to fmt if it is not a
 130  * constant. Even with the outer if statement optimizing out.
 131  */
 132 #define event_trace_printk(ip, fmt, args...)                            \
 133 do {                                                                    \
 134         __trace_printk_check_format(fmt, ##args);                       \
 135         tracing_record_cmdline(current);                                \
 136         if (__builtin_constant_p(fmt)) {                                \
 137                 static const char *trace_printk_fmt                     \
 138                   __attribute__((section("__trace_printk_fmt"))) =      \
 139                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 140                                                                         \
 141                 __trace_bprintk(ip, trace_printk_fmt, ##args);          \
 142         } else                                                          \
 143                 __trace_printk(ip, fmt, ##args);                        \
 144 } while (0)
 145
 146 #define __common_field(type, item)                                      \
 147         ret = trace_define_field(event_call, #type, "common_" #item,    \
 148                                  offsetof(typeof(field.ent), item),     \
 149                                  sizeof(field.ent.item));               \
 150         if (ret)                                                        \
 151                 return ret;
 152
 153 #endif /* _LINUX_FTRACE_EVENT_H */