tmp_suning_uos_patched/drivers/oprofile/oprofile_files.c
Robert Richter 7df01d96b2 oprofile: disable write access to oprofilefs while profiler is running
Oprofile counters are setup when profiling is disabled. Thus, writing
to oprofilefs has no immediate effect. Changes are updated only after
oprofile is reenabled.

To keep userland and kernel states synchronized, we now allow
configuration of oprofile only if profiling is disabled.  In this case
it checks if the profiler is running and then disables write access to
oprofilefs by returning -EBUSY. The change should be backward
compatible with current oprofile userland daemon.

Acked-by: Maynard Johnson <maynardj@us.ibm.com>
Cc: William Cohen <wcohen@redhat.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-10-12 17:25:06 +02:00

195 lines
4.5 KiB
C

/**
* @file oprofile_files.c
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon <levon@movementarian.org>
*/
#include <linux/fs.h>
#include <linux/oprofile.h>
#include <linux/jiffies.h>
#include "event_buffer.h"
#include "oprofile_stats.h"
#include "oprof.h"
#define BUFFER_SIZE_DEFAULT 131072
#define CPU_BUFFER_SIZE_DEFAULT 8192
#define BUFFER_WATERSHED_DEFAULT 32768 /* FIXME: tune */
#define TIME_SLICE_DEFAULT 1
unsigned long oprofile_buffer_size;
unsigned long oprofile_cpu_buffer_size;
unsigned long oprofile_buffer_watershed;
unsigned long oprofile_time_slice;
#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
static ssize_t timeout_read(struct file *file, char __user *buf,
size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(jiffies_to_msecs(oprofile_time_slice),
buf, count, offset);
}
static ssize_t timeout_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;
retval = oprofile_set_timeout(val);
if (retval)
return retval;
return count;
}
static const struct file_operations timeout_fops = {
.read = timeout_read,
.write = timeout_write,
};
#endif
static ssize_t depth_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(oprofile_backtrace_depth, buf, count,
offset);
}
static ssize_t depth_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
unsigned long val;
int retval;
if (*offset)
return -EINVAL;
if (!oprofile_ops.backtrace)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
return retval;
retval = oprofile_set_ulong(&oprofile_backtrace_depth, val);
if (retval)
return retval;
return count;
}
static const struct file_operations depth_fops = {
.read = depth_read,
.write = depth_write
};
static ssize_t pointer_size_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(sizeof(void *), buf, count, offset);
}
static const struct file_operations pointer_size_fops = {
.read = pointer_size_read,
};
static ssize_t cpu_type_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_str_to_user(oprofile_ops.cpu_type, buf, count, offset);
}
static const struct file_operations cpu_type_fops = {
.read = cpu_type_read,
};
static ssize_t enable_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(oprofile_started, buf, count, offset);
}
static ssize_t enable_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 (val)
retval = oprofile_start();
else
oprofile_stop();
if (retval)
return retval;
return count;
}
static const struct file_operations enable_fops = {
.read = enable_read,
.write = enable_write,
};
static ssize_t dump_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
wake_up_buffer_waiter();
return count;
}
static const struct file_operations dump_fops = {
.write = dump_write,
};
void oprofile_create_files(struct super_block *sb, struct dentry *root)
{
/* reinitialize default values */
oprofile_buffer_size = BUFFER_SIZE_DEFAULT;
oprofile_cpu_buffer_size = CPU_BUFFER_SIZE_DEFAULT;
oprofile_buffer_watershed = BUFFER_WATERSHED_DEFAULT;
oprofile_time_slice = msecs_to_jiffies(TIME_SLICE_DEFAULT);
oprofilefs_create_file(sb, root, "enable", &enable_fops);
oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
oprofilefs_create_ulong(sb, root, "buffer_size", &oprofile_buffer_size);
oprofilefs_create_ulong(sb, root, "buffer_watershed", &oprofile_buffer_watershed);
oprofilefs_create_ulong(sb, root, "cpu_buffer_size", &oprofile_cpu_buffer_size);
oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
oprofilefs_create_file(sb, root, "time_slice", &timeout_fops);
#endif
oprofile_create_stats_files(sb, root);
if (oprofile_ops.create_files)
oprofile_ops.create_files(sb, root);
}