[deliverable/linux.git] / arch / x86 / kernel / msr.c

/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 2000 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 = -EINVAL;

	lock_kernel();
	switch (orig) {
	case 0:
		file->f_pos = offset;
		ret = file->f_pos;
		break;
	case 1:
		file->f_pos += offset;
		ret = file->f_pos;
	}
	unlock_kernel();
	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_DEAD:
		msr_device_destroy(cpu);
		break;
	case CPU_UP_CANCELED_FROZEN:
		destroy_suspended_device(msr_class, MKDEV(MSR_MAJOR, cpu));
		break;
	}
	return err ? NOTIFY_BAD : NOTIFY_OK;
}

static struct notifier_block __cpuinitdata 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");
Commit	Line	Data
1da177e4 LT	1	/* ----------------------------------------------------------------------- *
	2	*
	3	* Copyright 2000 H. Peter Anvin - All Rights Reserved
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
	8	* USA; either version 2 of the License, or (at your option) any later
	9	* version; incorporated herein by reference.
	10	*
	11	* ----------------------------------------------------------------------- */
	12
	13	/*
1da177e4 LT	14	* x86 MSR access device
	15	*
	16	* This device is accessed by lseek() to the appropriate register number
	17	* and then read/write in chunks of 8 bytes. A larger size means multiple
	18	* reads or writes of the same register.
	19	*
	20	* This driver uses /dev/cpu/%d/msr where %d is the minor number, and on
	21	* an SMP box will direct the access to CPU %d.
	22	*/
	23
	24	#include <linux/module.h>
1da177e4 LT	25
	26	#include <linux/types.h>
	27	#include <linux/errno.h>
	28	#include <linux/fcntl.h>
	29	#include <linux/init.h>
	30	#include <linux/poll.h>
	31	#include <linux/smp.h>
	32	#include <linux/smp_lock.h>
	33	#include <linux/major.h>
	34	#include <linux/fs.h>
	35	#include <linux/device.h>
	36	#include <linux/cpu.h>
	37	#include <linux/notifier.h>
	38
	39	#include <asm/processor.h>
	40	#include <asm/msr.h>
	41	#include <asm/uaccess.h>
	42	#include <asm/system.h>
	43
8874b414	44	static struct class *msr_class;
1da177e4	45
1da177e4 LT	46	static loff_t msr_seek(struct file *file, loff_t offset, int orig)
	47	{
	48	loff_t ret = -EINVAL;
	49
	50	lock_kernel();
	51	switch (orig) {
	52	case 0:
	53	file->f_pos = offset;
	54	ret = file->f_pos;
	55	break;
	56	case 1:
	57	file->f_pos += offset;
	58	ret = file->f_pos;
	59	}
	60	unlock_kernel();
	61	return ret;
	62	}
	63
	64	static ssize_t msr_read(struct file file, char __user buf,
	65	size_t count, loff_t * ppos)
	66	{
	67	u32 __user tmp = (u32 __user ) buf;
	68	u32 data[2];
1da177e4	69	u32 reg = *ppos;
aab4c5a5	70	int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	71	int err;
	72
	73	if (count % 8)
	74	return -EINVAL; /* Invalid chunk size */
	75
6926d570	76	for (; count; count -= 8) {
78a62d2c	77	err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
1da177e4	78	if (err)
78a62d2c	79	return -EIO;
1da177e4 LT	80	if (copy_to_user(tmp, &data, 8))
	81	return -EFAULT;
	82	tmp += 2;
	83	}
	84
	85	return ((char __user *)tmp) - buf;
	86	}
	87
	88	static ssize_t msr_write(struct file file, const char __user buf,
	89	size_t count, loff_t *ppos)
	90	{
	91	const u32 __user tmp = (const u32 __user )buf;
	92	u32 data[2];
1da177e4	93	u32 reg = *ppos;
aab4c5a5	94	int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	95	int err;
	96
	97	if (count % 8)
	98	return -EINVAL; /* Invalid chunk size */
	99
f475ff35	100	for (; count; count -= 8) {
1da177e4 LT	101	if (copy_from_user(&data, tmp, 8))
1da177e4 LT	102	return -EFAULT;
78a62d2c	103	err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
1da177e4	104	if (err)
78a62d2c	105	return -EIO;
1da177e4 LT	106	tmp += 2;
	107	}
	108
	109	return ((char __user *)tmp) - buf;
	110	}
	111
	112	static int msr_open(struct inode inode, struct file file)
	113	{
aab4c5a5	114	unsigned int cpu = iminor(file->f_path.dentry->d_inode);
92cb7612	115	struct cpuinfo_x86 *c = &cpu_data(cpu);
1da177e4 LT	116
	117	if (cpu >= NR_CPUS \|\| !cpu_online(cpu))
	118	return -ENXIO; /* No such CPU */
	119	if (!cpu_has(c, X86_FEATURE_MSR))
	120	return -EIO; /* MSR not supported */
	121
	122	return 0;
	123	}
	124
	125	/*
	126	* File operations we support
	127	*/
5dfe4c96	128	static const struct file_operations msr_fops = {
1da177e4 LT	129	.owner = THIS_MODULE,
	130	.llseek = msr_seek,
	131	.read = msr_read,
	132	.write = msr_write,
	133	.open = msr_open,
	134	};
	135
38048983	136	static int __cpuinit msr_device_create(int cpu)
1da177e4	137	{
a271aaf1	138	struct device *dev;
1da177e4	139
881a841f AM	140	dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu),
	141	"msr%d", cpu);
	142	return IS_ERR(dev) ? PTR_ERR(dev) : 0;
	143	}
	144
	145	static void msr_device_destroy(int cpu)
	146	{
	147	device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
1da177e4 LT	148	}
1da177e4 LT	149
761c4bf8	150	static int __cpuinit msr_class_cpu_callback(struct notifier_block *nfb,
e09793bb	151	unsigned long action, void *hcpu)
1da177e4 LT	152	{
1da177e4 LT	153	unsigned int cpu = (unsigned long)hcpu;
881a841f	154	int err = 0;
1da177e4 LT	155
1da177e4 LT	156	switch (action) {
881a841f	157	case CPU_UP_PREPARE:
881a841f	158	err = msr_device_create(cpu);
1da177e4	159	break;
881a841f	160	case CPU_UP_CANCELED:
1da177e4	161	case CPU_DEAD:
881a841f	162	msr_device_destroy(cpu);
1da177e4	163	break;
775b64d2 RW	164	case CPU_UP_CANCELED_FROZEN:
	165	destroy_suspended_device(msr_class, MKDEV(MSR_MAJOR, cpu));
	166	break;
1da177e4	167	}
881a841f	168	return err ? NOTIFY_BAD : NOTIFY_OK;
1da177e4 LT	169	}
1da177e4 LT	170
881a841f	171	static struct notifier_block __cpuinitdata msr_class_cpu_notifier = {
1da177e4 LT	172	.notifier_call = msr_class_cpu_callback,
	173	};
	174
	175	static int __init msr_init(void)
	176	{
	177	int i, err = 0;
	178	i = 0;
	179
	180	if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
	181	printk(KERN_ERR "msr: unable to get major %d for msr\n",
	182	MSR_MAJOR);
	183	err = -EBUSY;
	184	goto out;
	185	}
8874b414	186	msr_class = class_create(THIS_MODULE, "msr");
1da177e4 LT	187	if (IS_ERR(msr_class)) {
	188	err = PTR_ERR(msr_class);
	189	goto out_chrdev;
	190	}
	191	for_each_online_cpu(i) {
a271aaf1	192	err = msr_device_create(i);
1da177e4 LT	193	if (err != 0)
	194	goto out_class;
	195	}
e09793bb	196	register_hotcpu_notifier(&msr_class_cpu_notifier);
1da177e4 LT	197
	198	err = 0;
	199	goto out;
	200
	201	out_class:
	202	i = 0;
	203	for_each_online_cpu(i)
881a841f	204	msr_device_destroy(i);
8874b414	205	class_destroy(msr_class);
1da177e4 LT	206	out_chrdev:
	207	unregister_chrdev(MSR_MAJOR, "cpu/msr");
	208	out:
	209	return err;
	210	}
	211
	212	static void __exit msr_exit(void)
	213	{
	214	int cpu = 0;
	215	for_each_online_cpu(cpu)
881a841f	216	msr_device_destroy(cpu);
8874b414	217	class_destroy(msr_class);
1da177e4	218	unregister_chrdev(MSR_MAJOR, "cpu/msr");
e09793bb	219	unregister_hotcpu_notifier(&msr_class_cpu_notifier);
1da177e4 LT	220	}
	221
	222	module_init(msr_init);
	223	module_exit(msr_exit)
	224
	225	MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
	226	MODULE_DESCRIPTION("x86 generic MSR driver");
	227	MODULE_LICENSE("GPL");