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/**
* Copyright (C) ARM Limited 2010-2012. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include "gator.h"
#include <trace/events/irq.h>
#define HARDIRQ 0
#define SOFTIRQ 1
#define TOTALIRQ (SOFTIRQ+1)
static ulong hardirq_enabled;
static ulong softirq_enabled;
static ulong hardirq_key;
static ulong softirq_key;
static DEFINE_PER_CPU(int[TOTALIRQ], irqCnt);
static DEFINE_PER_CPU(int[TOTALIRQ * 2], irqGet);
GATOR_DEFINE_PROBE(irq_handler_exit, TP_PROTO(int irq,
struct irqaction *action, int ret))
{
unsigned long flags;
// disable interrupts to synchronize with gator_events_irq_read()
// spinlocks not needed since percpu buffers are used
local_irq_save(flags);
per_cpu(irqCnt, smp_processor_id())[HARDIRQ]++;
local_irq_restore(flags);
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 37)
GATOR_DEFINE_PROBE(softirq_exit, TP_PROTO(struct softirq_action *h, struct softirq_action *vec))
#else
GATOR_DEFINE_PROBE(softirq_exit, TP_PROTO(unsigned int vec_nr))
#endif
{
unsigned long flags;
// disable interrupts to synchronize with gator_events_irq_read()
// spinlocks not needed since percpu buffers are used
local_irq_save(flags);
per_cpu(irqCnt, smp_processor_id())[SOFTIRQ]++;
local_irq_restore(flags);
}
static int gator_events_irq_create_files(struct super_block *sb, struct dentry *root)
{
struct dentry *dir;
/* irq */
dir = gatorfs_mkdir(sb, root, "Linux_irq_irq");
if (!dir) {
return -1;
}
gatorfs_create_ulong(sb, dir, "enabled", &hardirq_enabled);
gatorfs_create_ro_ulong(sb, dir, "key", &hardirq_key);
/* soft irq */
dir = gatorfs_mkdir(sb, root, "Linux_irq_softirq");
if (!dir) {
return -1;
}
gatorfs_create_ulong(sb, dir, "enabled", &softirq_enabled);
gatorfs_create_ro_ulong(sb, dir, "key", &softirq_key);
return 0;
}
static int gator_events_irq_online(int** buffer)
{
int len = 0, cpu = smp_processor_id();
unsigned long flags; // not necessary as we are in interrupt context anyway, but doesn't hurt
// synchronization with the irq_exit functions is not necessary as the values are being reset
if (hardirq_enabled) {
local_irq_save(flags);
per_cpu(irqCnt, cpu)[HARDIRQ] = 0;
local_irq_restore(flags);
per_cpu(irqGet, cpu)[len++] = hardirq_key;
per_cpu(irqGet, cpu)[len++] = 0;
}
if (softirq_enabled) {
local_irq_save(flags);
per_cpu(irqCnt, cpu)[SOFTIRQ] = 0;
local_irq_restore(flags);
per_cpu(irqGet, cpu)[len++] = softirq_key;
per_cpu(irqGet, cpu)[len++] = 0;
}
if (buffer)
*buffer = per_cpu(irqGet, cpu);
return len;
}
static int gator_events_irq_start(void)
{
// register tracepoints
if (hardirq_enabled)
if (GATOR_REGISTER_TRACE(irq_handler_exit))
goto fail_hardirq_exit;
if (softirq_enabled)
if (GATOR_REGISTER_TRACE(softirq_exit))
goto fail_softirq_exit;
pr_debug("gator: registered irq tracepoints\n");
return 0;
// unregister tracepoints on error
fail_softirq_exit:
if (hardirq_enabled)
GATOR_UNREGISTER_TRACE(irq_handler_exit);
fail_hardirq_exit:
pr_err("gator: irq tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
return -1;
}
static void gator_events_irq_stop(void)
{
if (hardirq_enabled)
GATOR_UNREGISTER_TRACE(irq_handler_exit);
if (softirq_enabled)
GATOR_UNREGISTER_TRACE(softirq_exit);
pr_debug("gator: unregistered irq tracepoints\n");
hardirq_enabled = 0;
softirq_enabled = 0;
}
static int gator_events_irq_read(int **buffer)
{
unsigned long flags; // not necessary as we are in interrupt context anyway, but doesn't hurt
int len, value;
int cpu = smp_processor_id();
len = 0;
if (hardirq_enabled) {
local_irq_save(flags);
value = per_cpu(irqCnt, cpu)[HARDIRQ];
per_cpu(irqCnt, cpu)[HARDIRQ] = 0;
local_irq_restore(flags);
per_cpu(irqGet, cpu)[len++] = hardirq_key;
per_cpu(irqGet, cpu)[len++] = value;
}
if (softirq_enabled) {
local_irq_save(flags);
value = per_cpu(irqCnt, cpu)[SOFTIRQ];
per_cpu(irqCnt, cpu)[SOFTIRQ] = 0;
local_irq_restore(flags);
per_cpu(irqGet, cpu)[len++] = softirq_key;
per_cpu(irqGet, cpu)[len++] = value;
}
if (buffer)
*buffer = per_cpu(irqGet, cpu);
return len;
}
static struct gator_interface gator_events_irq_interface = {
.create_files = gator_events_irq_create_files,
.online = gator_events_irq_online,
.start = gator_events_irq_start,
.stop = gator_events_irq_stop,
.read = gator_events_irq_read,
};
int gator_events_irq_init(void)
{
hardirq_key = gator_events_get_key();
softirq_key = gator_events_get_key();
hardirq_enabled = 0;
softirq_enabled = 0;
return gator_events_install(&gator_events_irq_interface);
}
gator_events_init(gator_events_irq_init);
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