linux/kernel/trace/trace_export.c
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   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)     \
  57struct ____ftrace_##name {                                              \
  58        tstruct                                                         \
  59};                                                                      \
  60static 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)     \
 128static int __init                                                       \
 129ftrace_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                                                                        \
 167struct 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                                                                        \
 174struct 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};                                                                      \
 183struct 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
 191bool ftrace_event_is_function(struct trace_event_call *call)
 192{
 193        return call == &event_function;
 194}
 195
 196#include "trace_entries.h"
 197