linux/kernel/trace/trace_preemptirq.c

// SPDX-License-Identifier: GPL-2.0
/*
 * preemptoff and irqoff tracepoints
 *
 * Copyright (C) Joel Fernandes (Google) <[email protected]>
 */

#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/kprobes.h>
#include "trace.h"

#define CREATE_TRACE_POINTS
#include <trace/events/preemptirq.h>

/*
 * Use regular trace points on architectures that implement noinstr
 * tooling: these calls will only happen with RCU enabled, which can
 * use a regular tracepoint.
 *
 * On older architectures, use the rcuidle tracing methods (which
 * aren't NMI-safe - so exclude NMI contexts):
 */
#ifdef CONFIG_ARCH_WANTS_NO_INSTR
#define trace(point) …
#else
#define trace …
#endif

#ifdef CONFIG_TRACE_IRQFLAGS
/* Per-cpu variable to prevent redundant calls when IRQs already off */
static DEFINE_PER_CPU(int, tracing_irq_cpu);

/*
 * Like trace_hardirqs_on() but without the lockdep invocation. This is
 * used in the low level entry code where the ordering vs. RCU is important
 * and lockdep uses a staged approach which splits the lockdep hardirq
 * tracking into a RCU on and a RCU off section.
 */
void trace_hardirqs_on_prepare(void)
{ … }
EXPORT_SYMBOL(…);
NOKPROBE_SYMBOL(trace_hardirqs_on_prepare);

void trace_hardirqs_on(void)
{ … }
EXPORT_SYMBOL(…);
NOKPROBE_SYMBOL(trace_hardirqs_on);

/*
 * Like trace_hardirqs_off() but without the lockdep invocation. This is
 * used in the low level entry code where the ordering vs. RCU is important
 * and lockdep uses a staged approach which splits the lockdep hardirq
 * tracking into a RCU on and a RCU off section.
 */
void trace_hardirqs_off_finish(void)
{ … }
EXPORT_SYMBOL(…);
NOKPROBE_SYMBOL(trace_hardirqs_off_finish);

void trace_hardirqs_off(void)
{ … }
EXPORT_SYMBOL(…);
NOKPROBE_SYMBOL(trace_hardirqs_off);
#endif /* CONFIG_TRACE_IRQFLAGS */

#ifdef CONFIG_TRACE_PREEMPT_TOGGLE

void trace_preempt_on(unsigned long a0, unsigned long a1)
{ … }

void trace_preempt_off(unsigned long a0, unsigned long a1)
{ … }
#endif