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0429578016
Currently we have in something like the sched_switch event: field:char prev_comm[TASK_COMM_LEN]; offset:12; size:16; signed:1; When a userspace tool such as perf tries to parse this, the TASK_COMM_LEN is meaningless. This is done because the TRACE_EVENT() macro simply uses a #len to show the string of the length. When the length is an enum, we get a string that means nothing for tools. By adding a static buffer and a mutex to protect it, we can store the string into that buffer with snprintf and show the actual number. Now we get: field:char prev_comm[16]; offset:12; size:16; signed:1; Something much more useful. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
174 lines
4.5 KiB
C
174 lines
4.5 KiB
C
/*
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* trace_export.c - export basic ftrace utilities to user space
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*
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* Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
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*/
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#include <linux/stringify.h>
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#include <linux/kallsyms.h>
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#include <linux/seq_file.h>
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#include <linux/debugfs.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include "trace_output.h"
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#undef TRACE_SYSTEM
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#define TRACE_SYSTEM ftrace
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/* not needed for this file */
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#undef __field_struct
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#define __field_struct(type, item)
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#undef __field
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#define __field(type, item) type item;
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#undef __field_desc
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#define __field_desc(type, container, item) type item;
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#undef __array
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#define __array(type, item, size) type item[size];
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#undef __array_desc
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#define __array_desc(type, container, item, size) type item[size];
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#undef __dynamic_array
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#define __dynamic_array(type, item) type item[];
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#undef F_STRUCT
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#define F_STRUCT(args...) args
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#undef F_printk
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#define F_printk(fmt, args...) fmt, args
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#undef FTRACE_ENTRY
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#define FTRACE_ENTRY(name, struct_name, id, tstruct, print) \
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struct ____ftrace_##name { \
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tstruct \
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}; \
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static void __always_unused ____ftrace_check_##name(void) \
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{ \
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struct ____ftrace_##name *__entry = NULL; \
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\
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/* force compile-time check on F_printk() */ \
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printk(print); \
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}
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#undef FTRACE_ENTRY_DUP
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#define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print) \
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FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
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#include "trace_entries.h"
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#undef __field
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#define __field(type, item) \
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ret = trace_define_field(event_call, #type, #item, \
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offsetof(typeof(field), item), \
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sizeof(field.item), \
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is_signed_type(type), FILTER_OTHER); \
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if (ret) \
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return ret;
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#undef __field_desc
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#define __field_desc(type, container, item) \
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ret = trace_define_field(event_call, #type, #item, \
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offsetof(typeof(field), \
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container.item), \
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sizeof(field.container.item), \
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is_signed_type(type), FILTER_OTHER); \
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if (ret) \
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return ret;
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#undef __array
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#define __array(type, item, len) \
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do { \
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BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
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mutex_lock(&event_storage_mutex); \
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snprintf(event_storage, sizeof(event_storage), \
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"%s[%d]", #type, len); \
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ret = trace_define_field(event_call, event_storage, #item, \
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offsetof(typeof(field), item), \
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sizeof(field.item), \
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is_signed_type(type), FILTER_OTHER); \
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mutex_unlock(&event_storage_mutex); \
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if (ret) \
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return ret; \
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} while (0);
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#undef __array_desc
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#define __array_desc(type, container, item, len) \
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BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
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ret = trace_define_field(event_call, #type "[" #len "]", #item, \
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offsetof(typeof(field), \
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container.item), \
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sizeof(field.container.item), \
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is_signed_type(type), FILTER_OTHER); \
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if (ret) \
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return ret;
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#undef __dynamic_array
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#define __dynamic_array(type, item) \
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ret = trace_define_field(event_call, #type, #item, \
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offsetof(typeof(field), item), \
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0, is_signed_type(type), FILTER_OTHER);\
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if (ret) \
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return ret;
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#undef FTRACE_ENTRY
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#define FTRACE_ENTRY(name, struct_name, id, tstruct, print) \
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int \
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ftrace_define_fields_##name(struct ftrace_event_call *event_call) \
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{ \
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struct struct_name field; \
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int ret; \
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\
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tstruct; \
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\
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return ret; \
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}
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#include "trace_entries.h"
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#undef __entry
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#define __entry REC
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#undef __field
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#define __field(type, item)
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#undef __field_desc
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#define __field_desc(type, container, item)
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#undef __array
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#define __array(type, item, len)
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#undef __array_desc
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#define __array_desc(type, container, item, len)
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#undef __dynamic_array
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#define __dynamic_array(type, item)
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#undef F_printk
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#define F_printk(fmt, args...) #fmt ", " __stringify(args)
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#undef FTRACE_ENTRY
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#define FTRACE_ENTRY(call, struct_name, etype, tstruct, print) \
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\
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struct ftrace_event_class event_class_ftrace_##call = { \
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.system = __stringify(TRACE_SYSTEM), \
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.define_fields = ftrace_define_fields_##call, \
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.fields = LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
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}; \
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\
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struct ftrace_event_call __used \
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__attribute__((__aligned__(4))) \
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__attribute__((section("_ftrace_events"))) event_##call = { \
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.name = #call, \
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.event.type = etype, \
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.class = &event_class_ftrace_##call, \
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.print_fmt = print, \
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}; \
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#include "trace_entries.h"
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