130 lines
3.5 KiB
C
130 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* preemptoff and irqoff tracepoints
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*
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* Copyright (C) Joel Fernandes (Google) <joel@joelfernandes.org>
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*/
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#include <linux/kallsyms.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/ftrace.h>
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#include <linux/kprobes.h>
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#include <linux/hardirq.h>
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#include "trace.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/preemptirq.h>
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/*
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* Use regular trace points on architectures that implement noinstr
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* tooling: these calls will only happen with RCU enabled, which can
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* use a regular tracepoint.
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*
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* On older architectures, RCU may not be watching in idle. In that
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* case, wake up RCU to watch while calling the tracepoint. These
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* aren't NMI-safe - so exclude NMI contexts:
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*/
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#ifdef CONFIG_ARCH_WANTS_NO_INSTR
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#define trace(point, args) trace_##point(args)
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#else
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#define trace(point, args) \
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do { \
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if (trace_##point##_enabled()) { \
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bool exit_rcu = false; \
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if (in_nmi()) \
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break; \
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if (!IS_ENABLED(CONFIG_TINY_RCU) && \
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is_idle_task(current)) { \
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ct_irq_enter(); \
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exit_rcu = true; \
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} \
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trace_##point(args); \
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if (exit_rcu) \
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ct_irq_exit(); \
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} \
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} while (0)
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#endif
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#ifdef CONFIG_TRACE_IRQFLAGS
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/* Per-cpu variable to prevent redundant calls when IRQs already off */
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static DEFINE_PER_CPU(int, tracing_irq_cpu);
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/*
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* Like trace_hardirqs_on() but without the lockdep invocation. This is
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* used in the low level entry code where the ordering vs. RCU is important
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* and lockdep uses a staged approach which splits the lockdep hardirq
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* tracking into a RCU on and a RCU off section.
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*/
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void trace_hardirqs_on_prepare(void)
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{
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if (this_cpu_read(tracing_irq_cpu)) {
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trace(irq_enable, TP_ARGS(CALLER_ADDR0, CALLER_ADDR1));
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tracer_hardirqs_on(CALLER_ADDR0, CALLER_ADDR1);
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this_cpu_write(tracing_irq_cpu, 0);
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}
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}
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EXPORT_SYMBOL(trace_hardirqs_on_prepare);
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NOKPROBE_SYMBOL(trace_hardirqs_on_prepare);
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void trace_hardirqs_on(void)
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{
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if (this_cpu_read(tracing_irq_cpu)) {
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trace(irq_enable, TP_ARGS(CALLER_ADDR0, CALLER_ADDR1));
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tracer_hardirqs_on(CALLER_ADDR0, CALLER_ADDR1);
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this_cpu_write(tracing_irq_cpu, 0);
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}
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lockdep_hardirqs_on_prepare();
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lockdep_hardirqs_on(CALLER_ADDR0);
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}
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EXPORT_SYMBOL(trace_hardirqs_on);
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NOKPROBE_SYMBOL(trace_hardirqs_on);
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/*
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* Like trace_hardirqs_off() but without the lockdep invocation. This is
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* used in the low level entry code where the ordering vs. RCU is important
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* and lockdep uses a staged approach which splits the lockdep hardirq
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* tracking into a RCU on and a RCU off section.
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*/
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void trace_hardirqs_off_finish(void)
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{
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if (!this_cpu_read(tracing_irq_cpu)) {
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this_cpu_write(tracing_irq_cpu, 1);
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tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1);
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trace(irq_disable, TP_ARGS(CALLER_ADDR0, CALLER_ADDR1));
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}
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}
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EXPORT_SYMBOL(trace_hardirqs_off_finish);
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NOKPROBE_SYMBOL(trace_hardirqs_off_finish);
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void trace_hardirqs_off(void)
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{
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lockdep_hardirqs_off(CALLER_ADDR0);
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if (!this_cpu_read(tracing_irq_cpu)) {
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this_cpu_write(tracing_irq_cpu, 1);
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tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1);
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trace(irq_disable, TP_ARGS(CALLER_ADDR0, CALLER_ADDR1));
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}
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}
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EXPORT_SYMBOL(trace_hardirqs_off);
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NOKPROBE_SYMBOL(trace_hardirqs_off);
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#endif /* CONFIG_TRACE_IRQFLAGS */
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#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
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void trace_preempt_on(unsigned long a0, unsigned long a1)
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{
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trace(preempt_enable, TP_ARGS(a0, a1));
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tracer_preempt_on(a0, a1);
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}
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void trace_preempt_off(unsigned long a0, unsigned long a1)
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{
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trace(preempt_disable, TP_ARGS(a0, a1));
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tracer_preempt_off(a0, a1);
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}
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#endif
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