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 accessible 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 __field_packed
  49 #define __field_packed(type, container, item)           type item;
  50
  51 #undef __array
  52 #define __array(type, item, size)                       type item[size];
  53
  54 #undef __array_desc
  55 #define __array_desc(type, container, item, size)       type item[size];
  56
  57 #undef __dynamic_array
  58 #define __dynamic_array(type, item)                     type item[];
  59
  60 #undef F_STRUCT
  61 #define F_STRUCT(args...)                               args
  62
  63 #undef F_printk
  64 #define F_printk(fmt, args...) fmt, args
  65
  66 #undef FTRACE_ENTRY
  67 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)             \
  68 struct ____ftrace_##name {                                              \
  69         tstruct                                                         \
  70 };                                                                      \
  71 static void __always_unused ____ftrace_check_##name(void)               \
  72 {                                                                       \
  73         struct ____ftrace_##name *__entry = NULL;                       \
  74                                                                         \
  75         /* force compile-time check on F_printk() */                    \
  76         printk(print);                                                  \
  77 }
  78
  79 #undef FTRACE_ENTRY_DUP
  80 #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print)         \
  81         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
  82
  83 #include "trace_entries.h"
  84
  85 #undef __field_ext
  86 #define __field_ext(_type, _item, _filter_type) {                       \
  87         .type = #_type, .name = #_item,                                 \
  88         .size = sizeof(_type), .align = __alignof__(_type),             \
  89         is_signed_type(_type), .filter_type = _filter_type },
  90
  91
  92 #undef __field_ext_packed
  93 #define __field_ext_packed(_type, _item, _filter_type) {        \
  94         .type = #_type, .name = #_item,                         \
  95         .size = sizeof(_type), .align = 1,                      \
  96         is_signed_type(_type), .filter_type = _filter_type },
  97
  98 #undef __field
  99 #define __field(_type, _item) __field_ext(_type, _item, FILTER_OTHER)
 100
 101 #undef __field_fn
 102 #define __field_fn(_type, _item) __field_ext(_type, _item, FILTER_TRACE_FN)
 103
 104 #undef __field_desc
 105 #define __field_desc(_type, _container, _item) __field_ext(_type, _item, FILTER_OTHER)
 106
 107 #undef __field_packed
 108 #define __field_packed(_type, _container, _item) __field_ext_packed(_type, _item, FILTER_OTHER)
 109
 110 #undef __array
 111 #define __array(_type, _item, _len) {                                   \
 112         .type = #_type"["__stringify(_len)"]", .name = #_item,          \
 113         .size = sizeof(_type[_len]), .align = __alignof__(_type),       \
 114         is_signed_type(_type), .filter_type = FILTER_OTHER },
 115
 116 #undef __array_desc
 117 #define __array_desc(_type, _container, _item, _len) __array(_type, _item, _len)
 118
 119 #undef __dynamic_array
 120 #define __dynamic_array(_type, _item) {                                 \
 121         .type = #_type "[]", .name = #_item,                            \
 122         .size = 0, .align = __alignof__(_type),                         \
 123         is_signed_type(_type), .filter_type = FILTER_OTHER },
 124
 125 #undef FTRACE_ENTRY
 126 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)             \
 127 static struct trace_event_fields ftrace_event_fields_##name[] = {       \
 128         tstruct                                                         \
 129         {} };
 130
 131 #include "trace_entries.h"
 132
 133 #undef __entry
 134 #define __entry REC
 135
 136 #undef __field
 137 #define __field(type, item)
 138
 139 #undef __field_fn
 140 #define __field_fn(type, item)
 141
 142 #undef __field_desc
 143 #define __field_desc(type, container, item)
 144
 145 #undef __field_packed
 146 #define __field_packed(type, container, item)
 147
 148 #undef __array
 149 #define __array(type, item, len)
 150
 151 #undef __array_desc
 152 #define __array_desc(type, container, item, len)
 153
 154 #undef __dynamic_array
 155 #define __dynamic_array(type, item)
 156
 157 #undef F_printk
 158 #define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
 159
 160 #undef FTRACE_ENTRY_REG
 161 #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, regfn) \
 162 static struct trace_event_class __refdata event_class_ftrace_##call = { \
 163         .system                 = __stringify(TRACE_SYSTEM),            \
 164         .fields_array           = ftrace_event_fields_##call,           \
 165         .fields                 = LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
 166         .reg                    = regfn,                                \
 167 };                                                                      \
 168                                                                         \
 169 struct trace_event_call __used event_##call = {                         \
 170         .class                  = &event_class_ftrace_##call,           \
 171         {                                                               \
 172                 .name                   = #call,                        \
 173         },                                                              \
 174         .event.type             = etype,                                \
 175         .print_fmt              = print,                                \
 176         .flags                  = TRACE_EVENT_FL_IGNORE_ENABLE,         \
 177 };                                                                      \
 178 static struct trace_event_call __used                                           \
 179 __section("_ftrace_events") *__event_##call = &event_##call;
 180
 181 #undef FTRACE_ENTRY
 182 #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print)          \
 183         FTRACE_ENTRY_REG(call, struct_name, etype,                      \
 184                          PARAMS(tstruct), PARAMS(print), NULL)
 185
 186 bool ftrace_event_is_function(struct trace_event_call *call)
 187 {
 188         return call == &event_function;
 189 }
 190
 191 #include "trace_entries.h"