linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * trace irqs off critical timings

 *

 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>

 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>

 *

 * From code in the latency_tracer, that is:

 *

 *  Copyright (C) 2004-2006 Ingo Molnar

 *  Copyright (C) 2004 Nadia Yvette Chambers

 */

#include <linux/kallsyms.h>

#include <linux/uaccess.h>

#include <linux/module.h>

#include <linux/ftrace.h>

#include <linux/kprobes.h>

​

#include "trace.h"

​

#include <trace/events/preemptirq.h>

​

#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)

static struct trace_array       *irqsoff_trace __read_mostly;

static int              tracer_enabled __read_mostly;

​

static DEFINE_PER_CPU(int, tracing_cpu);

​

static DEFINE_RAW_SPINLOCK(max_trace_lock);

​

enum {

    TRACER_IRQS_OFF     = (1 << 1),

    TRACER_PREEMPT_OFF  = (1 << 2),

};

​

static int trace_type __read_mostly;

​

static int save_flags;

​

static void stop_irqsoff_tracer(struct trace_array *tr, int graph);

static int start_irqsoff_tracer(struct trace_array *tr, int graph);

​

#ifdef CONFIG_PREEMPT_TRACER

static inline int

preempt_trace(int pc)

{

    return ((trace_type & TRACER_PREEMPT_OFF) && pc);

}

#else

# define preempt_trace(pc) (0)

#endif

​

#ifdef CONFIG_IRQSOFF_TRACER

static inline int

irq_trace(void)

{

    return ((trace_type & TRACER_IRQS_OFF) &&

        irqs_disabled());

}

#else

# define irq_trace() (0)

#endif

​

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

static int irqsoff_display_graph(struct trace_array *tr, int set);

# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)

#else

static inline int irqsoff_display_graph(struct trace_array *tr, int set)

{

    return -EINVAL;

}

# define is_graph(tr) false

#endif

​

/*

 * Sequence count - we record it when starting a measurement and

 * skip the latency if the sequence has changed - some other section

 * did a maximum and could disturb our measurement with serial console

 * printouts, etc. Truly coinciding maximum latencies should be rare

 * and what happens together happens separately as well, so this doesn't

 * decrease the validity of the maximum found:

 */

static __cacheline_aligned_in_smp   unsigned long max_sequence;

​

#ifdef CONFIG_FUNCTION_TRACER

/*

 * Prologue for the preempt and irqs off function tracers.

 *

 * Returns 1 if it is OK to continue, and data->disabled is

 *            incremented.

 *         0 if the trace is to be ignored, and data->disabled

 *            is kept the same.