linux/arch/x86/kernel/msr.c
Rafael J. Wysocki b844eba292 PM: Remove destroy_suspended_device()
After 2.6.24 there was a plan to make the PM core acquire all device
semaphores during a suspend/hibernation to protect itself from
concurrent operations involving device objects.  That proved to be
too heavy-handed and we found a better way to achieve the goal, but
before it happened, we had introduced the functions
device_pm_schedule_removal() and destroy_suspended_device() to allow
drivers to "safely" destroy a suspended device and we had adapted some
drivers to use them.  Now that these functions are no longer necessary,
it seems reasonable to remove them and modify their users to use the
normal device unregistration instead.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-19 19:10:28 -07:00

230 lines
5.1 KiB
C

/* ----------------------------------------------------------------------- *
*
* Copyright 2000-2008 H. Peter Anvin - 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 as published by
* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
* USA; either version 2 of the License, or (at your option) any later
* version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* x86 MSR access device
*
* This device is accessed by lseek() to the appropriate register number
* and then read/write in chunks of 8 bytes. A larger size means multiple
* reads or writes of the same register.
*
* This driver uses /dev/cpu/%d/msr where %d is the minor number, and on
* an SMP box will direct the access to CPU %d.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/uaccess.h>
#include <asm/system.h>
static struct class *msr_class;
static loff_t msr_seek(struct file *file, loff_t offset, int orig)
{
loff_t ret;
struct inode *inode = file->f_mapping->host;
mutex_lock(&inode->i_mutex);
switch (orig) {
case 0:
file->f_pos = offset;
ret = file->f_pos;
break;
case 1:
file->f_pos += offset;
ret = file->f_pos;
break;
default:
ret = -EINVAL;
}
mutex_unlock(&inode->i_mutex);
return ret;
}
static ssize_t msr_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
u32 __user *tmp = (u32 __user *) buf;
u32 data[2];
u32 reg = *ppos;
int cpu = iminor(file->f_path.dentry->d_inode);
int err;
if (count % 8)
return -EINVAL; /* Invalid chunk size */
for (; count; count -= 8) {
err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
if (err)
return -EIO;
if (copy_to_user(tmp, &data, 8))
return -EFAULT;
tmp += 2;
}
return ((char __user *)tmp) - buf;
}
static ssize_t msr_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
const u32 __user *tmp = (const u32 __user *)buf;
u32 data[2];
u32 reg = *ppos;
int cpu = iminor(file->f_path.dentry->d_inode);
int err;
if (count % 8)
return -EINVAL; /* Invalid chunk size */
for (; count; count -= 8) {
if (copy_from_user(&data, tmp, 8))
return -EFAULT;
err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
if (err)
return -EIO;
tmp += 2;
}
return ((char __user *)tmp) - buf;
}
static int msr_open(struct inode *inode, struct file *file)
{
unsigned int cpu = iminor(file->f_path.dentry->d_inode);
struct cpuinfo_x86 *c = &cpu_data(cpu);
if (cpu >= NR_CPUS || !cpu_online(cpu))
return -ENXIO; /* No such CPU */
if (!cpu_has(c, X86_FEATURE_MSR))
return -EIO; /* MSR not supported */
return 0;
}
/*
* File operations we support
*/
static const struct file_operations msr_fops = {
.owner = THIS_MODULE,
.llseek = msr_seek,
.read = msr_read,
.write = msr_write,
.open = msr_open,
};
static int __cpuinit msr_device_create(int cpu)
{
struct device *dev;
dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu),
"msr%d", cpu);
return IS_ERR(dev) ? PTR_ERR(dev) : 0;
}
static void msr_device_destroy(int cpu)
{
device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
}
static int __cpuinit msr_class_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
int err = 0;
switch (action) {
case CPU_UP_PREPARE:
err = msr_device_create(cpu);
break;
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
msr_device_destroy(cpu);
break;
}
return err ? NOTIFY_BAD : NOTIFY_OK;
}
static struct notifier_block __refdata msr_class_cpu_notifier = {
.notifier_call = msr_class_cpu_callback,
};
static int __init msr_init(void)
{
int i, err = 0;
i = 0;
if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
printk(KERN_ERR "msr: unable to get major %d for msr\n",
MSR_MAJOR);
err = -EBUSY;
goto out;
}
msr_class = class_create(THIS_MODULE, "msr");
if (IS_ERR(msr_class)) {
err = PTR_ERR(msr_class);
goto out_chrdev;
}
for_each_online_cpu(i) {
err = msr_device_create(i);
if (err != 0)
goto out_class;
}
register_hotcpu_notifier(&msr_class_cpu_notifier);
err = 0;
goto out;
out_class:
i = 0;
for_each_online_cpu(i)
msr_device_destroy(i);
class_destroy(msr_class);
out_chrdev:
unregister_chrdev(MSR_MAJOR, "cpu/msr");
out:
return err;
}
static void __exit msr_exit(void)
{
int cpu = 0;
for_each_online_cpu(cpu)
msr_device_destroy(cpu);
class_destroy(msr_class);
unregister_chrdev(MSR_MAJOR, "cpu/msr");
unregister_hotcpu_notifier(&msr_class_cpu_notifier);
}
module_init(msr_init);
module_exit(msr_exit)
MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
MODULE_DESCRIPTION("x86 generic MSR driver");
MODULE_LICENSE("GPL");