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/**
* @file common.c
*
* @remark Copyright 2004 Oprofile Authors
* @remark Copyright 2010 ARM Ltd.
* @remark Read the file COPYING
*
* @author Zwane Mwaikambo
* @author Will Deacon [move to perf]
*/
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/oprofile.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <asm/stacktrace.h>
#include <linux/uaccess.h>
#include <asm/perf_event.h>
#include <asm/ptrace.h>
#ifdef CONFIG_HW_PERF_EVENTS
/*
* Per performance monitor configuration as set via oprofilefs.
*/
struct op_counter_config {
unsigned long count;
unsigned long enabled;
unsigned long event;
unsigned long unit_mask;
unsigned long kernel;
unsigned long user;
struct perf_event_attr attr;
};
static int op_arm_enabled;
static DEFINE_MUTEX(op_arm_mutex);
static struct op_counter_config *counter_config;
static struct perf_event **perf_events[nr_cpumask_bits];
static int perf_num_counters;
/*
* Overflow callback for oprofile.
*/
static void op_overflow_handler(struct perf_event *event, int unused,
struct perf_sample_data *data, struct pt_regs *regs)
{
int id;
u32 cpu = smp_processor_id();
for (id = 0; id < perf_num_counters; ++id)
if (perf_events[cpu][id] == event)
break;
if (id != perf_num_counters)
oprofile_add_sample(regs, id);
else
pr_warning("oprofile: ignoring spurious overflow "
"on cpu %u\n", cpu);
}
/*
* Called by op_arm_setup to create perf attributes to mirror the oprofile
* settings in counter_config. Attributes are created as `pinned' events and
* so are permanently scheduled on the PMU.
*/
static void op_perf_setup(void)
{
int i;
u32 size = sizeof(struct perf_event_attr);
struct perf_event_attr *attr;
for (i = 0; i < perf_num_counters; ++i) {
attr = &counter_config[i].attr;
memset(attr, 0, size);
attr->type = PERF_TYPE_RAW;
attr->size = size;
attr->config = counter_config[i].event;
attr->sample_period = counter_config[i].count;
attr->pinned = 1;
}
}
static int op_create_counter(int cpu, int event)
{
int ret = 0;
struct perf_event *pevent;
if (!counter_config[event].enabled || (perf_events[cpu][event] != NULL))
return ret;
pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
cpu, -1,
op_overflow_handler);
if (IS_ERR(pevent)) {
ret = PTR_ERR(pevent);
} else if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
pr_warning("oprofile: failed to enable event %d "
"on CPU %d\n", event, cpu);
ret = -EBUSY;
} else {
perf_events[cpu][event] = pevent;
}
return ret;
}
static void op_destroy_counter(int cpu, int event)
{
struct perf_event *pevent = perf_events[cpu][event];
if (pevent) {
perf_event_release_kernel(pevent);
perf_events[cpu][event] = NULL;
}
}
/*
* Called by op_arm_start to create active perf events based on the
* perviously configured attributes.
*/
static int op_perf_start(void)
{
int cpu, event, ret = 0;
for_each_online_cpu(cpu) {
for (event = 0; event < perf_num_counters; ++event) {
ret = op_create_counter(cpu, event);
if (ret)
goto out;
}
}
out:
return ret;
}
/*
* Called by op_arm_stop at the end of a profiling run.
*/
static void op_perf_stop(void)
{
int cpu, event;
for_each_online_cpu(cpu)
for (event = 0; event < perf_num_counters; ++event)
op_destroy_counter(cpu, event);
}
static char *op_name_from_perf_id(enum arm_perf_pmu_ids id)
{
switch (id) {
case ARM_PERF_PMU_ID_XSCALE1:
return "arm/xscale1";
case ARM_PERF_PMU_ID_XSCALE2:
return "arm/xscale2";
case ARM_PERF_PMU_ID_V6:
return "arm/armv6";
case ARM_PERF_PMU_ID_V6MP:
return "arm/mpcore";
case ARM_PERF_PMU_ID_CA8:
return "arm/armv7";
case ARM_PERF_PMU_ID_CA9:
return "arm/armv7-ca9";
default:
return NULL;
}
}
static int op_arm_create_files(struct super_block *sb, struct dentry *root)
{
unsigned int i;
for (i = 0; i < perf_num_counters; i++) {
struct dentry *dir;
char buf[4];
snprintf(buf, sizeof buf, "%d", i);
dir = oprofilefs_mkdir(sb, root, buf);
oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
}
return 0;
}
static int op_arm_setup(void)
{
spin_lock(&oprofilefs_lock);
op_perf_setup();
spin_unlock(&oprofilefs_lock);
return 0;
}
static int op_arm_start(void)
{
int ret = -EBUSY;
mutex_lock(&op_arm_mutex);
if (!op_arm_enabled) {
ret = 0;
op_perf_start();
op_arm_enabled = 1;
}
mutex_unlock(&op_arm_mutex);
return ret;
}
static void op_arm_stop(void)
{
mutex_lock(&op_arm_mutex);
if (op_arm_enabled)
op_perf_stop();
op_arm_enabled = 0;
mutex_unlock(&op_arm_mutex);
}
#ifdef CONFIG_PM
static int op_arm_suspend(struct platform_device *dev, pm_message_t state)
{
mutex_lock(&op_arm_mutex);
if (op_arm_enabled)
op_perf_stop();
mutex_unlock(&op_arm_mutex);
return 0;
}
static int op_arm_resume(struct platform_device *dev)
{
mutex_lock(&op_arm_mutex);
if (op_arm_enabled && op_perf_start())
op_arm_enabled = 0;
mutex_unlock(&op_arm_mutex);
return 0;
}
static struct platform_driver oprofile_driver = {
.driver = {
.name = "arm-oprofile",
},
.resume = op_arm_resume,
.suspend = op_arm_suspend,
};
static struct platform_device *oprofile_pdev;
static int __init init_driverfs(void)
{
int ret;
ret = platform_driver_register(&oprofile_driver);
if (ret)
goto out;
oprofile_pdev = platform_device_register_simple(
oprofile_driver.driver.name, 0, NULL, 0);
if (IS_ERR(oprofile_pdev)) {
ret = PTR_ERR(oprofile_pdev);
platform_driver_unregister(&oprofile_driver);
}
out:
return ret;
}
static void __exit exit_driverfs(void)
{
platform_device_unregister(oprofile_pdev);
platform_driver_unregister(&oprofile_driver);
}
#else
static int __init init_driverfs(void) { return 0; }
#define exit_driverfs() do { } while (0)
#endif /* CONFIG_PM */
static int report_trace(struct stackframe *frame, void *d)
{
unsigned int *depth = d;
if (*depth) {
oprofile_add_trace(frame->pc);
(*depth)--;
}
return *depth == 0;
}
/*
* The registers we're interested in are at the end of the variable
* length saved register structure. The fp points at the end of this
* structure so the address of this struct is:
* (struct frame_tail *)(xxx->fp)-1
*/
struct frame_tail {
struct frame_tail *fp;
unsigned long sp;
unsigned long lr;
} __attribute__((packed));
static struct frame_tail* user_backtrace(struct frame_tail *tail)
{
struct frame_tail buftail[2];
/* Also check accessibility of one struct frame_tail beyond */
if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
return NULL;
if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
return NULL;
oprofile_add_trace(buftail[0].lr);
/* frame pointers should strictly progress back up the stack
* (towards higher addresses) */
if (tail >= buftail[0].fp)
return NULL;
return buftail[0].fp-1;
}
static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
{
struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
if (!user_mode(regs)) {
struct stackframe frame;
frame.fp = regs->ARM_fp;
frame.sp = regs->ARM_sp;
frame.lr = regs->ARM_lr;
frame.pc = regs->ARM_pc;
walk_stackframe(&frame, report_trace, &depth);
return;
}
while (depth-- && tail && !((unsigned long) tail & 3))
tail = user_backtrace(tail);
}
int __init oprofile_arch_init(struct oprofile_operations *ops)
{
int cpu, ret = 0;
perf_num_counters = armpmu_get_max_events();
counter_config = kcalloc(perf_num_counters,
sizeof(struct op_counter_config), GFP_KERNEL);
if (!counter_config) {
pr_info("oprofile: failed to allocate %d "
"counters\n", perf_num_counters);
ret = -ENOMEM;
goto out;
}
ret = init_driverfs();
if (ret)
goto out;
for_each_possible_cpu(cpu) {
perf_events[cpu] = kcalloc(perf_num_counters,
sizeof(struct perf_event *), GFP_KERNEL);
if (!perf_events[cpu]) {
pr_info("oprofile: failed to allocate %d perf events "
"for cpu %d\n", perf_num_counters, cpu);
ret = -ENOMEM;
goto out;
}
}
ops->backtrace = arm_backtrace;
ops->create_files = op_arm_create_files;
ops->setup = op_arm_setup;
ops->start = op_arm_start;
ops->stop = op_arm_stop;
ops->shutdown = op_arm_stop;
ops->cpu_type = op_name_from_perf_id(armpmu_get_pmu_id());
if (!ops->cpu_type)
ret = -ENODEV;
else
pr_info("oprofile: using %s\n", ops->cpu_type);
out:
if (ret) {
for_each_possible_cpu(cpu)
kfree(perf_events[cpu]);
kfree(counter_config);
}
return ret;
}
void __exit oprofile_arch_exit(void)
{
int cpu, id;
struct perf_event *event;
for_each_possible_cpu(cpu) {
for (id = 0; id < perf_num_counters; ++id) {
event = perf_events[cpu][id];
if (event)
perf_event_release_kernel(event);
}
kfree(perf_events[cpu]);
}
kfree(counter_config);
exit_driverfs();
}
#else
int __init oprofile_arch_init(struct oprofile_operations *ops)
{
pr_info("oprofile: hardware counters not available\n");
return -ENODEV;
}
void __exit oprofile_arch_exit(void) {}
#endif /* CONFIG_HW_PERF_EVENTS */
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