kernel/trace/trace_export.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_export.c - export basic ftrace utilities to user space
   4  *
   5  * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
   6  */
   7 #include <linux/stringify.h>
   8 #include <linux/kallsyms.h>
   9 #include <linux/seq_file.h>
  10 #include <linux/uaccess.h>
  11 #include <linux/ftrace.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14
  15 #include "trace_output.h"
  16
  17 /* Stub function for events with triggers */
  18 static int ftrace_event_register(struct trace_event_call *call,
  19                                  enum trace_reg type, void *data)
  20 {
  21         return 0;
  22 }
  23
  24 #undef TRACE_SYSTEM
  25 #define TRACE_SYSTEM    ftrace
  26
  27 /*
  28  * The FTRACE_ENTRY_REG macro allows ftrace entry to define register
  29  * function and thus become accesible via perf.
  30  */
  31 #undef FTRACE_ENTRY_REG
  32 #define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, regfn) \
  33         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
  34
  35 /* not needed for this file */
  36 #undef __field_struct
  37 #define __field_struct(type, item)
  38
  39 #undef __field
  40 #define __field(type, item)                             type item;
  41
  42 #undef __field_fn
  43 #define __field_fn(type, item)                          type item;
  44
  45 #undef __field_desc
  46 #define __field_desc(type, container, item)             type item;
  47
  48 #undef __array
  49 #define __array(type, item, size)                       type item[size];
  50
  51 #undef __array_desc
  52 #define __array_desc(type, container, item, size)       type item[size];
  53
  54 #undef __dynamic_array
  55 #define __dynamic_array(type, item)                     type item[];
  56
  57 #undef F_STRUCT
  58 #define F_STRUCT(args...)                               args
  59
  60 #undef F_printk
  61 #define F_printk(fmt, args...) fmt, args
  62
  63 #undef FTRACE_ENTRY
  64 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)             \
  65 struct ____ftrace_##name {                                              \
  66         tstruct                                                         \
  67 };                                                                      \
  68 static void __always_unused ____ftrace_check_##name(void)               \
  69 {                                                                       \
  70         struct ____ftrace_##name *__entry = NULL;                       \
  71                                                                         \
  72         /* force compile-time check on F_printk() */                    \
  73         printk(print);                                                  \
  74 }
  75
  76 #undef FTRACE_ENTRY_DUP
  77 #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print)         \
  78         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
  79
  80 #include "trace_entries.h"
  81
  82 #undef __field_ext
  83 #define __field_ext(_type, _item, _filter_type) {                       \
  84         .type = #_type, .name = #_item,                                 \
  85         .size = sizeof(_type), .align = __alignof__(_type),             \
  86         is_signed_type(_type), .filter_type = _filter_type },
  87
  88 #undef __field
  89 #define __field(_type, _item) __field_ext(_type, _item, FILTER_OTHER)
  90
  91 #undef __field_fn
  92 #define __field_fn(_type, _item) __field_ext(_type, _item, FILTER_TRACE_FN)
  93
  94 #undef __field_desc
  95 #define __field_desc(_type, _container, _item) __field_ext(_type, _item, FILTER_OTHER)
  96
  97 #undef __array
  98 #define __array(_type, _item, _len) {                                   \
  99         .type = #_type"["__stringify(_len)"]", .name = #_item,          \
 100         .size = sizeof(_type[_len]), .align = __alignof__(_type),       \
 101         is_signed_type(_type), .filter_type = FILTER_OTHER },
 102
 103 #undef __array_desc
 104 #define __array_desc(_type, _container, _item, _len) __array(_type, _item, _len)
 105
 106 #undef __dynamic_array
 107 #define __dynamic_array(_type, _item) {                                 \
 108         .type = #_type "[]", .name = #_item,                            \
 109         .size = 0, .align = __alignof__(_type),                         \
 110         is_signed_type(_type), .filter_type = FILTER_OTHER },
 111
 112 #undef FTRACE_ENTRY
 113 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)             \
 114 static struct trace_event_fields ftrace_event_fields_##name[] = {       \
 115         tstruct                                                         \
 116         {} };
 117
 118 #include "trace_entries.h"
 119
 120 #undef __entry
 121 #define __entry REC
 122
 123 #undef __field
 124 #define __field(type, item)
 125
 126 #undef __field_fn
 127 #define __field_fn(type, item)
 128
 129 #undef __field_desc
 130 #define __field_desc(type, container, item)
 131
 132 #undef __array
 133 #define __array(type, item, len)
 134
 135 #undef __array_desc
 136 #define __array_desc(type, container, item, len)
 137
 138 #undef __dynamic_array
 139 #define __dynamic_array(type, item)
 140
 141 #undef F_printk
 142 #define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
 143
 144 #undef FTRACE_ENTRY_REG
 145 #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, regfn) \
 146 static struct trace_event_class __refdata event_class_ftrace_##call = { \
 147         .system                 = __stringify(TRACE_SYSTEM),            \
 148         .fields_array           = ftrace_event_fields_##call,           \
 149         .fields                 = LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
 150         .reg                    = regfn,                                \
 151 };                                                                      \
 152                                                                         \
 153 struct trace_event_call __used event_##call = {                         \
 154         .class                  = &event_class_ftrace_##call,           \
 155         {                                                               \
 156                 .name                   = #call,                        \
 157         },                                                              \
 158         .event.type             = etype,                                \
 159         .print_fmt              = print,                                \
 160         .flags                  = TRACE_EVENT_FL_IGNORE_ENABLE,         \
 161 };                                                                      \
 162 static struct trace_event_call __used                                           \
 163 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
 164
 165 #undef FTRACE_ENTRY
 166 #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print)          \
 167         FTRACE_ENTRY_REG(call, struct_name, etype,                      \
 168                          PARAMS(tstruct), PARAMS(print), NULL)
 169
 170 bool ftrace_event_is_function(struct trace_event_call *call)
 171 {
 172         return call == &event_function;
 173 }
 174
 175 #include "trace_entries.h"