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/**
* arch/s390/oprofile/hwsampler_files.c
*
* Copyright IBM Corp. 2010
* Author: Mahesh Salgaonkar (mahesh@linux.vnet.ibm.com)
*/
#include <linux/oprofile.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include "../../../drivers/oprofile/oprof.h"
#include "hwsampler.h"
#define DEFAULT_INTERVAL 4096
#define DEFAULT_SDBT_BLOCKS 1
#define DEFAULT_SDB_BLOCKS 511
static unsigned long oprofile_hw_interval = DEFAULT_INTERVAL;
static unsigned long oprofile_min_interval;
static unsigned long oprofile_max_interval;
static unsigned long oprofile_sdbt_blocks = DEFAULT_SDBT_BLOCKS;
static unsigned long oprofile_sdb_blocks = DEFAULT_SDB_BLOCKS;
static int hwsampler_file;
static int hwsampler_running; /* start_mutex must be held to change */
static struct oprofile_operations timer_ops;
static int oprofile_hwsampler_start(void)
{
int retval;
hwsampler_running = hwsampler_file;
if (!hwsampler_running)
return timer_ops.start();
retval = hwsampler_allocate(oprofile_sdbt_blocks, oprofile_sdb_blocks);
if (retval)
return retval;
retval = hwsampler_start_all(oprofile_hw_interval);
if (retval)
hwsampler_deallocate();
return retval;
}
static void oprofile_hwsampler_stop(void)
{
if (!hwsampler_running) {
timer_ops.stop();
return;
}
hwsampler_stop_all();
hwsampler_deallocate();
return;
}
static ssize_t hwsampler_read(struct file *file, char __user *buf,
size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(hwsampler_file, buf, count, offset);
}
static ssize_t hwsampler_write(struct file *file, char const __user *buf,
size_t count, loff_t *offset)
{
unsigned long val;
int retval;
if (*offset)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
return retval;
if (oprofile_started)
/*
* save to do without locking as we set
* hwsampler_running in start() when start_mutex is
* held
*/
return -EBUSY;
hwsampler_file = val;
return count;
}
static const struct file_operations hwsampler_fops = {
.read = hwsampler_read,
.write = hwsampler_write,
};
static int oprofile_create_hwsampling_files(struct super_block *sb,
struct dentry *root)
{
struct dentry *hw_dir;
/* reinitialize default values */
hwsampler_file = 1;
hw_dir = oprofilefs_mkdir(sb, root, "hwsampling");
if (!hw_dir)
return -EINVAL;
oprofilefs_create_file(sb, hw_dir, "hwsampler", &hwsampler_fops);
oprofilefs_create_ulong(sb, hw_dir, "hw_interval",
&oprofile_hw_interval);
oprofilefs_create_ro_ulong(sb, hw_dir, "hw_min_interval",
&oprofile_min_interval);
oprofilefs_create_ro_ulong(sb, hw_dir, "hw_max_interval",
&oprofile_max_interval);
oprofilefs_create_ulong(sb, hw_dir, "hw_sdbt_blocks",
&oprofile_sdbt_blocks);
return 0;
}
int oprofile_hwsampler_init(struct oprofile_operations* ops)
{
if (hwsampler_setup())
return -ENODEV;
/*
* create hwsampler files only if hwsampler_setup() succeeds.
*/
oprofile_min_interval = hwsampler_query_min_interval();
if (oprofile_min_interval < 0) {
oprofile_min_interval = 0;
return -ENODEV;
}
oprofile_max_interval = hwsampler_query_max_interval();
if (oprofile_max_interval < 0) {
oprofile_max_interval = 0;
return -ENODEV;
}
if (oprofile_timer_init(ops))
return -ENODEV;
printk(KERN_INFO "oprofile: using hardware sampling\n");
memcpy(&timer_ops, ops, sizeof(timer_ops));
ops->start = oprofile_hwsampler_start;
ops->stop = oprofile_hwsampler_stop;
ops->create_files = oprofile_create_hwsampling_files;
return 0;
}
void oprofile_hwsampler_exit(void)
{
oprofile_timer_exit();
hwsampler_shutdown();
}
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