[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / i386 / 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.
 *
 * ----------------------------------------------------------------------- */

/*
 * msr.c
 *
 * 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 msr_device_create(int i)
{
	int err = 0;
	struct device *dev;

	dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, i), "msr%d",i);
	if (IS_ERR(dev))
		err = PTR_ERR(dev);
	return err;
}

static int msr_class_cpu_callback(struct notifier_block *nfb,
				unsigned long action, void *hcpu)
{
	unsigned int cpu = (unsigned long)hcpu;

	switch (action) {
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		msr_device_create(cpu);
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
		break;
	}
	return 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)
		device_destroy(msr_class, MKDEV(MSR_MAJOR, 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)
		device_destroy(msr_class, MKDEV(MSR_MAJOR, 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	/*
	14	* msr.c
	15	*
	16	* x86 MSR access device
	17	*
	18	* This device is accessed by lseek() to the appropriate register number
	19	* and then read/write in chunks of 8 bytes. A larger size means multiple
	20	* reads or writes of the same register.
	21	*
	22	* This driver uses /dev/cpu/%d/msr where %d is the minor number, and on
	23	* an SMP box will direct the access to CPU %d.
	24	*/
	25
	26	#include <linux/module.h>
1da177e4 LT	27
	28	#include <linux/types.h>
	29	#include <linux/errno.h>
	30	#include <linux/fcntl.h>
	31	#include <linux/init.h>
	32	#include <linux/poll.h>
	33	#include <linux/smp.h>
	34	#include <linux/smp_lock.h>
	35	#include <linux/major.h>
	36	#include <linux/fs.h>
	37	#include <linux/device.h>
	38	#include <linux/cpu.h>
	39	#include <linux/notifier.h>
	40
	41	#include <asm/processor.h>
	42	#include <asm/msr.h>
	43	#include <asm/uaccess.h>
	44	#include <asm/system.h>
	45
8874b414	46	static struct class *msr_class;
1da177e4	47
1da177e4 LT	48	static loff_t msr_seek(struct file *file, loff_t offset, int orig)
	49	{
	50	loff_t ret = -EINVAL;
	51
	52	lock_kernel();
	53	switch (orig) {
	54	case 0:
	55	file->f_pos = offset;
	56	ret = file->f_pos;
	57	break;
	58	case 1:
	59	file->f_pos += offset;
	60	ret = file->f_pos;
	61	}
	62	unlock_kernel();
	63	return ret;
	64	}
	65
	66	static ssize_t msr_read(struct file file, char __user buf,
	67	size_t count, loff_t * ppos)
	68	{
	69	u32 __user tmp = (u32 __user ) buf;
	70	u32 data[2];
1da177e4	71	u32 reg = *ppos;
aab4c5a5	72	int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	73	int err;
	74
	75	if (count % 8)
	76	return -EINVAL; /* Invalid chunk size */
	77
6926d570	78	for (; count; count -= 8) {
78a62d2c	79	err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
1da177e4	80	if (err)
78a62d2c	81	return -EIO;
1da177e4 LT	82	if (copy_to_user(tmp, &data, 8))
	83	return -EFAULT;
	84	tmp += 2;
	85	}
	86
	87	return ((char __user *)tmp) - buf;
	88	}
	89
	90	static ssize_t msr_write(struct file file, const char __user buf,
	91	size_t count, loff_t *ppos)
	92	{
	93	const u32 __user tmp = (const u32 __user )buf;
	94	u32 data[2];
1da177e4	95	u32 reg = *ppos;
aab4c5a5	96	int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	97	int err;
	98
	99	if (count % 8)
	100	return -EINVAL; /* Invalid chunk size */
	101
f475ff35	102	for (; count; count -= 8) {
1da177e4 LT	103	if (copy_from_user(&data, tmp, 8))
1da177e4 LT	104	return -EFAULT;
78a62d2c	105	err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
1da177e4	106	if (err)
78a62d2c	107	return -EIO;
1da177e4 LT	108	tmp += 2;
	109	}
	110
	111	return ((char __user *)tmp) - buf;
	112	}
	113
	114	static int msr_open(struct inode inode, struct file file)
	115	{
aab4c5a5	116	unsigned int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	117	struct cpuinfo_x86 *c = &(cpu_data)[cpu];
	118
	119	if (cpu >= NR_CPUS \|\| !cpu_online(cpu))
	120	return -ENXIO; /* No such CPU */
	121	if (!cpu_has(c, X86_FEATURE_MSR))
	122	return -EIO; /* MSR not supported */
	123
	124	return 0;
	125	}
	126
	127	/*
	128	* File operations we support
	129	*/
5dfe4c96	130	static const struct file_operations msr_fops = {
1da177e4 LT	131	.owner = THIS_MODULE,
	132	.llseek = msr_seek,
	133	.read = msr_read,
	134	.write = msr_write,
	135	.open = msr_open,
	136	};
	137
a271aaf1	138	static int msr_device_create(int i)
1da177e4 LT	139	{
1da177e4 LT	140	int err = 0;
a271aaf1	141	struct device *dev;
1da177e4	142
a271aaf1 GKH	143	dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, i), "msr%d",i);
	144	if (IS_ERR(dev))
	145	err = PTR_ERR(dev);
1da177e4 LT	146	return err;
	147	}
	148
e09793bb AM	149	static int msr_class_cpu_callback(struct notifier_block *nfb,
e09793bb AM	150	unsigned long action, void *hcpu)
1da177e4 LT	151	{
	152	unsigned int cpu = (unsigned long)hcpu;
	153
	154	switch (action) {
	155	case CPU_ONLINE:
8bb78442	156	case CPU_ONLINE_FROZEN:
a271aaf1	157	msr_device_create(cpu);
1da177e4 LT	158	break;
1da177e4 LT	159	case CPU_DEAD:
8bb78442	160	case CPU_DEAD_FROZEN:
a271aaf1	161	device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
1da177e4 LT	162	break;
	163	}
	164	return NOTIFY_OK;
	165	}
	166
74b85f37	167	static struct notifier_block __cpuinitdata msr_class_cpu_notifier =
1da177e4 LT	168	{
	169	.notifier_call = msr_class_cpu_callback,
	170	};
	171
	172	static int __init msr_init(void)
	173	{
	174	int i, err = 0;
	175	i = 0;
	176
	177	if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
	178	printk(KERN_ERR "msr: unable to get major %d for msr\n",
	179	MSR_MAJOR);
	180	err = -EBUSY;
	181	goto out;
	182	}
8874b414	183	msr_class = class_create(THIS_MODULE, "msr");
1da177e4 LT	184	if (IS_ERR(msr_class)) {
	185	err = PTR_ERR(msr_class);
	186	goto out_chrdev;
	187	}
	188	for_each_online_cpu(i) {
a271aaf1	189	err = msr_device_create(i);
1da177e4 LT	190	if (err != 0)
	191	goto out_class;
	192	}
e09793bb	193	register_hotcpu_notifier(&msr_class_cpu_notifier);
1da177e4 LT	194
	195	err = 0;
	196	goto out;
	197
	198	out_class:
	199	i = 0;
	200	for_each_online_cpu(i)
a271aaf1	201	device_destroy(msr_class, MKDEV(MSR_MAJOR, i));
8874b414	202	class_destroy(msr_class);
1da177e4 LT	203	out_chrdev:
	204	unregister_chrdev(MSR_MAJOR, "cpu/msr");
	205	out:
	206	return err;
	207	}
	208
	209	static void __exit msr_exit(void)
	210	{
	211	int cpu = 0;
	212	for_each_online_cpu(cpu)
a271aaf1	213	device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
8874b414	214	class_destroy(msr_class);
1da177e4	215	unregister_chrdev(MSR_MAJOR, "cpu/msr");
e09793bb	216	unregister_hotcpu_notifier(&msr_class_cpu_notifier);
1da177e4 LT	217	}
	218
	219	module_init(msr_init);
	220	module_exit(msr_exit)
	221
	222	MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
	223	MODULE_DESCRIPTION("x86 generic MSR driver");
	224	MODULE_LICENSE("GPL");