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 #undef TRACE_SYSTEM
  18 #define TRACE_SYSTEM    ftrace
  19
  20 /*
  21  * The FTRACE_ENTRY_REG macro allows ftrace entry to define register
  22  * function and thus become accesible via perf.
  23  */
  24 #undef FTRACE_ENTRY_REG
  25 #define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, \
  26                          filter, regfn) \
  27         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
  28                      filter)
  29
  30 /* not needed for this file */
  31 #undef __field_struct
  32 #define __field_struct(type, item)
  33
  34 #undef __field
  35 #define __field(type, item)                             type item;
  36
  37 #undef __field_desc
  38 #define __field_desc(type, container, item)             type item;
  39
  40 #undef __array
  41 #define __array(type, item, size)                       type item[size];
  42
  43 #undef __array_desc
  44 #define __array_desc(type, container, item, size)       type item[size];
  45
  46 #undef __dynamic_array
  47 #define __dynamic_array(type, item)                     type item[];
  48
  49 #undef F_STRUCT
  50 #define F_STRUCT(args...)                               args
  51
  52 #undef F_printk
  53 #define F_printk(fmt, args...) fmt, args
  54
  55 #undef FTRACE_ENTRY
  56 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)     \
  57 struct ____ftrace_##name {                                              \
  58         tstruct                                                         \
  59 };                                                                      \
  60 static void __always_unused ____ftrace_check_##name(void)               \
  61 {                                                                       \
  62         struct ____ftrace_##name *__entry = NULL;                       \
  63                                                                         \
  64         /* force compile-time check on F_printk() */                    \
  65         printk(print);                                                  \
  66 }
  67
  68 #undef FTRACE_ENTRY_DUP
  69 #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print, filter) \
  70         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
  71                      filter)
  72
  73 #include "trace_entries.h"
  74
  75 #undef __field
  76 #define __field(type, item)                                             \
  77         ret = trace_define_field(event_call, #type, #item,              \
  78                                  offsetof(typeof(field), item),         \
  79                                  sizeof(field.item),                    \
  80                                  is_signed_type(type), filter_type);    \
  81         if (ret)                                                        \
  82                 return ret;
  83
  84 #undef __field_desc
  85 #define __field_desc(type, container, item)     \
  86         ret = trace_define_field(event_call, #type, #item,              \
  87                                  offsetof(typeof(field),                \
  88                                           container.item),              \
  89                                  sizeof(field.container.item),          \
  90                                  is_signed_type(type), filter_type);    \
  91         if (ret)                                                        \
  92                 return ret;
  93
  94 #undef __array
  95 #define __array(type, item, len)                                        \
  96         do {                                                            \
  97                 char *type_str = #type"["__stringify(len)"]";           \
  98                 BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);                 \
  99                 ret = trace_define_field(event_call, type_str, #item,   \
 100                                  offsetof(typeof(field), item),         \
 101                                  sizeof(field.item),                    \
 102                                  is_signed_type(type), filter_type);    \
 103                 if (ret)                                                \
 104                         return ret;                                     \
 105         } while (0);
 106
 107 #undef __array_desc
 108 #define __array_desc(type, container, item, len)                        \
 109         BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);                         \
 110         ret = trace_define_field(event_call, #type "[" #len "]", #item, \
 111                                  offsetof(typeof(field),                \
 112                                           container.item),              \
 113                                  sizeof(field.container.item),          \
 114                                  is_signed_type(type), filter_type);    \
 115         if (ret)                                                        \
 116                 return ret;
 117
 118 #undef __dynamic_array
 119 #define __dynamic_array(type, item)                                     \
 120         ret = trace_define_field(event_call, #type, #item,              \
 121                                  offsetof(typeof(field), item),         \
 122                                  0, is_signed_type(type), filter_type);\
 123         if (ret)                                                        \
 124                 return ret;
 125
 126 #undef FTRACE_ENTRY
 127 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)     \
 128 static int __init                                                       \
 129 ftrace_define_fields_##name(struct trace_event_call *event_call)        \
 130 {                                                                       \
 131         struct struct_name field;                                       \
 132         int ret;                                                        \
 133         int filter_type = filter;                                       \
 134                                                                         \
 135         tstruct;                                                        \
 136                                                                         \
 137         return ret;                                                     \
 138 }
 139
 140 #include "trace_entries.h"
 141
 142 #undef __entry
 143 #define __entry REC
 144
 145 #undef __field
 146 #define __field(type, item)
 147
 148 #undef __field_desc
 149 #define __field_desc(type, container, item)
 150
 151 #undef __array
 152 #define __array(type, item, len)
 153
 154 #undef __array_desc
 155 #define __array_desc(type, container, item, len)
 156
 157 #undef __dynamic_array
 158 #define __dynamic_array(type, item)
 159
 160 #undef F_printk
 161 #define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
 162
 163 #undef FTRACE_ENTRY_REG
 164 #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, filter,\
 165                          regfn)                                         \
 166                                                                         \
 167 struct trace_event_class __refdata event_class_ftrace_##call = {        \
 168         .system                 = __stringify(TRACE_SYSTEM),            \
 169         .define_fields          = ftrace_define_fields_##call,          \
 170         .fields                 = LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
 171         .reg                    = regfn,                                \
 172 };                                                                      \
 173                                                                         \
 174 struct trace_event_call __used event_##call = {                         \
 175         .class                  = &event_class_ftrace_##call,           \
 176         {                                                               \
 177                 .name                   = #call,                        \
 178         },                                                              \
 179         .event.type             = etype,                                \
 180         .print_fmt              = print,                                \
 181         .flags                  = TRACE_EVENT_FL_IGNORE_ENABLE,         \
 182 };                                                                      \
 183 struct trace_event_call __used                                          \
 184 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
 185
 186 #undef FTRACE_ENTRY
 187 #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print, filter)  \
 188         FTRACE_ENTRY_REG(call, struct_name, etype,                      \
 189                          PARAMS(tstruct), PARAMS(print), filter, NULL)
 190
 191 bool ftrace_event_is_function(struct trace_event_call *call)
 192 {
 193         return call == &event_function;
 194 }
 195
 196 #include "trace_entries.h"