177 lines
3.5 KiB
C
177 lines
3.5 KiB
C
/**
|
|
* @file nmi_timer_int.c
|
|
*
|
|
* @remark Copyright 2011 Advanced Micro Devices, Inc.
|
|
*
|
|
* @author Robert Richter <robert.richter@amd.com>
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/oprofile.h>
|
|
#include <linux/perf_event.h>
|
|
|
|
#ifdef CONFIG_OPROFILE_NMI_TIMER
|
|
|
|
static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events);
|
|
static int ctr_running;
|
|
|
|
static struct perf_event_attr nmi_timer_attr = {
|
|
.type = PERF_TYPE_HARDWARE,
|
|
.config = PERF_COUNT_HW_CPU_CYCLES,
|
|
.size = sizeof(struct perf_event_attr),
|
|
.pinned = 1,
|
|
.disabled = 1,
|
|
};
|
|
|
|
static void nmi_timer_callback(struct perf_event *event,
|
|
struct perf_sample_data *data,
|
|
struct pt_regs *regs)
|
|
{
|
|
event->hw.interrupts = 0; /* don't throttle interrupts */
|
|
oprofile_add_sample(regs, 0);
|
|
}
|
|
|
|
static int nmi_timer_start_cpu(int cpu)
|
|
{
|
|
struct perf_event *event = per_cpu(nmi_timer_events, cpu);
|
|
|
|
if (!event) {
|
|
event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL,
|
|
nmi_timer_callback, NULL);
|
|
if (IS_ERR(event))
|
|
return PTR_ERR(event);
|
|
per_cpu(nmi_timer_events, cpu) = event;
|
|
}
|
|
|
|
if (event && ctr_running)
|
|
perf_event_enable(event);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void nmi_timer_stop_cpu(int cpu)
|
|
{
|
|
struct perf_event *event = per_cpu(nmi_timer_events, cpu);
|
|
|
|
if (event && ctr_running)
|
|
perf_event_disable(event);
|
|
}
|
|
|
|
static int nmi_timer_cpu_notifier(struct notifier_block *b, unsigned long action,
|
|
void *data)
|
|
{
|
|
int cpu = (unsigned long)data;
|
|
switch (action) {
|
|
case CPU_DOWN_FAILED:
|
|
case CPU_ONLINE:
|
|
nmi_timer_start_cpu(cpu);
|
|
break;
|
|
case CPU_DOWN_PREPARE:
|
|
nmi_timer_stop_cpu(cpu);
|
|
break;
|
|
}
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block nmi_timer_cpu_nb = {
|
|
.notifier_call = nmi_timer_cpu_notifier
|
|
};
|
|
|
|
static int nmi_timer_start(void)
|
|
{
|
|
int cpu;
|
|
|
|
get_online_cpus();
|
|
ctr_running = 1;
|
|
for_each_online_cpu(cpu)
|
|
nmi_timer_start_cpu(cpu);
|
|
put_online_cpus();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void nmi_timer_stop(void)
|
|
{
|
|
int cpu;
|
|
|
|
get_online_cpus();
|
|
for_each_online_cpu(cpu)
|
|
nmi_timer_stop_cpu(cpu);
|
|
ctr_running = 0;
|
|
put_online_cpus();
|
|
}
|
|
|
|
static void nmi_timer_shutdown(void)
|
|
{
|
|
struct perf_event *event;
|
|
int cpu;
|
|
|
|
cpu_notifier_register_begin();
|
|
__unregister_cpu_notifier(&nmi_timer_cpu_nb);
|
|
for_each_possible_cpu(cpu) {
|
|
event = per_cpu(nmi_timer_events, cpu);
|
|
if (!event)
|
|
continue;
|
|
perf_event_disable(event);
|
|
per_cpu(nmi_timer_events, cpu) = NULL;
|
|
perf_event_release_kernel(event);
|
|
}
|
|
|
|
cpu_notifier_register_done();
|
|
}
|
|
|
|
static int nmi_timer_setup(void)
|
|
{
|
|
int cpu, err;
|
|
u64 period;
|
|
|
|
/* clock cycles per tick: */
|
|
period = (u64)cpu_khz * 1000;
|
|
do_div(period, HZ);
|
|
nmi_timer_attr.sample_period = period;
|
|
|
|
cpu_notifier_register_begin();
|
|
err = __register_cpu_notifier(&nmi_timer_cpu_nb);
|
|
if (err)
|
|
goto out;
|
|
|
|
/* can't attach events to offline cpus: */
|
|
for_each_online_cpu(cpu) {
|
|
err = nmi_timer_start_cpu(cpu);
|
|
if (err) {
|
|
cpu_notifier_register_done();
|
|
nmi_timer_shutdown();
|
|
return err;
|
|
}
|
|
}
|
|
|
|
out:
|
|
cpu_notifier_register_done();
|
|
return err;
|
|
}
|
|
|
|
int __init op_nmi_timer_init(struct oprofile_operations *ops)
|
|
{
|
|
int err = 0;
|
|
|
|
err = nmi_timer_setup();
|
|
if (err)
|
|
return err;
|
|
nmi_timer_shutdown(); /* only check, don't alloc */
|
|
|
|
ops->create_files = NULL;
|
|
ops->setup = nmi_timer_setup;
|
|
ops->shutdown = nmi_timer_shutdown;
|
|
ops->start = nmi_timer_start;
|
|
ops->stop = nmi_timer_stop;
|
|
ops->cpu_type = "timer";
|
|
|
|
printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif
|