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, \
  33                          filter, regfn) \
  34         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
  35                      filter)
  36
  37 /* not needed for this file */
  38 #undef __field_struct
  39 #define __field_struct(type, item)
  40
  41 #undef __field
  42 #define __field(type, item)                             type item;
  43
  44 #undef __field_desc
  45 #define __field_desc(type, container, item)             type item;
  46
  47 #undef __array
  48 #define __array(type, item, size)                       type item[size];
  49
  50 #undef __array_desc
  51 #define __array_desc(type, container, item, size)       type item[size];
  52
  53 #undef __dynamic_array
  54 #define __dynamic_array(type, item)                     type item[];
  55
  56 #undef F_STRUCT
  57 #define F_STRUCT(args...)                               args
  58
  59 #undef F_printk
  60 #define F_printk(fmt, args...) fmt, args
  61
  62 #undef FTRACE_ENTRY
  63 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)     \
  64 struct ____ftrace_##name {                                              \
  65         tstruct                                                         \
  66 };                                                                      \
  67 static void __always_unused ____ftrace_check_##name(void)               \
  68 {                                                                       \
  69         struct ____ftrace_##name *__entry = NULL;                       \
  70                                                                         \
  71         /* force compile-time check on F_printk() */                    \
  72         printk(print);                                                  \
  73 }
  74
  75 #undef FTRACE_ENTRY_DUP
  76 #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print, filter) \
  77         FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
  78                      filter)
  79
  80 #include "trace_entries.h"
  81
  82 #undef __field
  83 #define __field(type, item)                                             \
  84         ret = trace_define_field(event_call, #type, #item,              \
  85                                  offsetof(typeof(field), item),         \
  86                                  sizeof(field.item),                    \
  87                                  is_signed_type(type), filter_type);    \
  88         if (ret)                                                        \
  89                 return ret;
  90
  91 #undef __field_desc
  92 #define __field_desc(type, container, item)     \
  93         ret = trace_define_field(event_call, #type, #item,              \
  94                                  offsetof(typeof(field),                \
  95                                           container.item),              \
  96                                  sizeof(field.container.item),          \
  97                                  is_signed_type(type), filter_type);    \
  98         if (ret)                                                        \
  99                 return ret;
 100
 101 #undef __array
 102 #define __array(type, item, len)                                        \
 103         do {                                                            \
 104                 char *type_str = #type"["__stringify(len)"]";           \
 105                 BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);                 \
 106                 ret = trace_define_field(event_call, type_str, #item,   \
 107                                  offsetof(typeof(field), item),         \
 108                                  sizeof(field.item),                    \
 109                                  is_signed_type(type), filter_type);    \
 110                 if (ret)                                                \
 111                         return ret;                                     \
 112         } while (0);
 113
 114 #undef __array_desc
 115 #define __array_desc(type, container, item, len)                        \
 116         BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);                         \
 117         ret = trace_define_field(event_call, #type "[" #len "]", #item, \
 118                                  offsetof(typeof(field),                \
 119                                           container.item),              \
 120                                  sizeof(field.container.item),          \
 121                                  is_signed_type(type), filter_type);    \
 122         if (ret)                                                        \
 123                 return ret;
 124
 125 #undef __dynamic_array
 126 #define __dynamic_array(type, item)                                     \
 127         ret = trace_define_field(event_call, #type "[]", #item,  \
 128                                  offsetof(typeof(field), item),         \
 129                                  0, is_signed_type(type), filter_type);\
 130         if (ret)                                                        \
 131                 return ret;
 132
 133 #undef FTRACE_ENTRY
 134 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)     \
 135 static int __init                                                       \
 136 ftrace_define_fields_##name(struct trace_event_call *event_call)        \
 137 {                                                                       \
 138         struct struct_name field;                                       \
 139         int ret;                                                        \
 140         int filter_type = filter;                                       \
 141                                                                         \
 142         tstruct;                                                        \
 143                                                                         \
 144         return ret;                                                     \
 145 }
 146
 147 #include "trace_entries.h"
 148
 149 #undef __entry
 150 #define __entry REC
 151
 152 #undef __field
 153 #define __field(type, item)
 154
 155 #undef __field_desc
 156 #define __field_desc(type, container, item)
 157
 158 #undef __array
 159 #define __array(type, item, len)
 160
 161 #undef __array_desc
 162 #define __array_desc(type, container, item, len)
 163
 164 #undef __dynamic_array
 165 #define __dynamic_array(type, item)
 166
 167 #undef F_printk
 168 #define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
 169
 170 #undef FTRACE_ENTRY_REG
 171 #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, filter,\
 172                          regfn)                                         \
 173                                                                         \
 174 struct trace_event_class __refdata event_class_ftrace_##call = {        \
 175         .system                 = __stringify(TRACE_SYSTEM),            \
 176         .define_fields          = ftrace_define_fields_##call,          \
 177         .fields                 = LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
 178         .reg                    = regfn,                                \
 179 };                                                                      \
 180                                                                         \
 181 struct trace_event_call __used event_##call = {                         \
 182         .class                  = &event_class_ftrace_##call,           \
 183         {                                                               \
 184                 .name                   = #call,                        \
 185         },                                                              \
 186         .event.type             = etype,                                \
 187         .print_fmt              = print,                                \
 188         .flags                  = TRACE_EVENT_FL_IGNORE_ENABLE,         \
 189 };                                                                      \
 190 struct trace_event_call __used                                          \
 191 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
 192
 193 #undef FTRACE_ENTRY
 194 #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print, filter)  \
 195         FTRACE_ENTRY_REG(call, struct_name, etype,                      \
 196                          PARAMS(tstruct), PARAMS(print), filter, NULL)
 197
 198 bool ftrace_event_is_function(struct trace_event_call *call)
 199 {
 200         return call == &event_function;
 201 }
 202
 203 #include "trace_entries.h"