3dd8095368
Allow writing to the trace_markers file initiate triggers defined in
tracefs/ftrace/print/trigger file. This will allow of user space to trigger
the same type of triggers (including histograms) that the trace events use.
Had to create a ftrace_event_register() function that will become the
trace_marker print event's reg() function. This is required because of how
triggers are enabled:
event_trigger_write() {
event_trigger_regex_write() {
trigger_process_regex() {
for p in trigger_commands {
p->func(); /* trigger_snapshot_cmd->func */
event_trigger_callback() {
cmd_ops->reg() /* register_trigger() */ {
trace_event_trigger_enable_disable() {
trace_event_enable_disable() {
call->class->reg();
Without the reg() function, the trigger code will call a NULL pointer and
crash the system.
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Karim Yaghmour <karim.yaghmour@opersys.com>
Cc: Brendan Gregg <bgregg@netflix.com>
Suggested-by: Joel Fernandes <joelaf@google.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
203 lines
5.3 KiB
C
203 lines
5.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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/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 "trace_output.h"
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/* Stub function for events with triggers */
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static int ftrace_event_register(struct trace_event_call *call,
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enum trace_reg type, void *data)
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{
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return 0;
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}
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#undef TRACE_SYSTEM
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#define TRACE_SYSTEM ftrace
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/*
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* The FTRACE_ENTRY_REG macro allows ftrace entry to define register
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* function and thus become accesible via perf.
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*/
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#undef FTRACE_ENTRY_REG
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#define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, \
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filter, regfn) \
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FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
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filter)
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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, filter) \
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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, filter) \
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FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
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filter)
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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_type); \
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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_type); \
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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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char *type_str = #type"["__stringify(len)"]"; \
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BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
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ret = trace_define_field(event_call, type_str, #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_type); \
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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_type); \
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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_type);\
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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, filter) \
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static int __init \
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ftrace_define_fields_##name(struct trace_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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int filter_type = filter; \
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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...) __stringify(fmt) ", " __stringify(args)
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#undef FTRACE_ENTRY_REG
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#define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, filter,\
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regfn) \
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\
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struct trace_event_class __refdata 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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.reg = regfn, \
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}; \
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\
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struct trace_event_call __used event_##call = { \
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.class = &event_class_ftrace_##call, \
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{ \
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.name = #call, \
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}, \
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.event.type = etype, \
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.print_fmt = print, \
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.flags = TRACE_EVENT_FL_IGNORE_ENABLE, \
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}; \
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struct trace_event_call __used \
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__attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
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#undef FTRACE_ENTRY
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#define FTRACE_ENTRY(call, struct_name, etype, tstruct, print, filter) \
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FTRACE_ENTRY_REG(call, struct_name, etype, \
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PARAMS(tstruct), PARAMS(print), filter, NULL)
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bool ftrace_event_is_function(struct trace_event_call *call)
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{
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return call == &event_function;
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}
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#include "trace_entries.h"
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