[linux-2.6-block.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/config.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 inline int wrmsr_eio(u32 reg, u32 eax, u32 edx)
{
	int err;

	err = wrmsr_safe(reg, eax, edx);
	if (err)
		err = -EIO;
	return err;
}

static inline int rdmsr_eio(u32 reg, u32 *eax, u32 *edx)
{
	int err;

	err = rdmsr_safe(reg, eax, edx);
	if (err)
		err = -EIO;
	return err;
}

#ifdef CONFIG_SMP

struct msr_command {
	int cpu;
	int err;
	u32 reg;
	u32 data[2];
};

static void msr_smp_wrmsr(void *cmd_block)
{
	struct msr_command *cmd = (struct msr_command *)cmd_block;

	if (cmd->cpu == smp_processor_id())
		cmd->err = wrmsr_eio(cmd->reg, cmd->data[0], cmd->data[1]);
}

static void msr_smp_rdmsr(void *cmd_block)
{
	struct msr_command *cmd = (struct msr_command *)cmd_block;

	if (cmd->cpu == smp_processor_id())
		cmd->err = rdmsr_eio(cmd->reg, &cmd->data[0], &cmd->data[1]);
}

static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
{
	struct msr_command cmd;
	int ret;

	preempt_disable();
	if (cpu == smp_processor_id()) {
		ret = wrmsr_eio(reg, eax, edx);
	} else {
		cmd.cpu = cpu;
		cmd.reg = reg;
		cmd.data[0] = eax;
		cmd.data[1] = edx;

		smp_call_function(msr_smp_wrmsr, &cmd, 1, 1);
		ret = cmd.err;
	}
	preempt_enable();
	return ret;
}

static inline int do_rdmsr(int cpu, u32 reg, u32 * eax, u32 * edx)
{
	struct msr_command cmd;
	int ret;

	preempt_disable();
	if (cpu == smp_processor_id()) {
		ret = rdmsr_eio(reg, eax, edx);
	} else {
		cmd.cpu = cpu;
		cmd.reg = reg;

		smp_call_function(msr_smp_rdmsr, &cmd, 1, 1);

		*eax = cmd.data[0];
		*edx = cmd.data[1];

		ret = cmd.err;
	}
	preempt_enable();
	return ret;
}

#else				/* ! CONFIG_SMP */

static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
{
	return wrmsr_eio(reg, eax, edx);
}

static inline int do_rdmsr(int cpu, u32 reg, u32 *eax, u32 *edx)
{
	return rdmsr_eio(reg, eax, edx);
}

#endif				/* ! CONFIG_SMP */

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_dentry->d_inode);
	int err;

	if (count % 8)
		return -EINVAL;	/* Invalid chunk size */

	for (; count; count -= 8) {
		err = do_rdmsr(cpu, reg, &data[0], &data[1]);
		if (err)
			return err;
		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];
	size_t rv;
	u32 reg = *ppos;
	int cpu = iminor(file->f_dentry->d_inode);
	int err;

	if (count % 8)
		return -EINVAL;	/* Invalid chunk size */

	for (rv = 0; count; count -= 8) {
		if (copy_from_user(&data, tmp, 8))
			return -EFAULT;
		err = do_wrmsr(cpu, reg, data[0], data[1]);
		if (err)
			return err;
		tmp += 2;
	}

	return ((char __user *)tmp) - buf;
}

static int msr_open(struct inode *inode, struct file *file)
{
	unsigned int cpu = iminor(file->f_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 struct file_operations msr_fops = {
	.owner = THIS_MODULE,
	.llseek = msr_seek,
	.read = msr_read,
	.write = msr_write,
	.open = msr_open,
};

static int msr_class_device_create(int i)
{
	int err = 0;
	struct class_device *class_err;

	class_err = class_device_create(msr_class, NULL, MKDEV(MSR_MAJOR, i), NULL, "msr%d",i);
	if (IS_ERR(class_err)) 
		err = PTR_ERR(class_err);
	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:
		msr_class_device_create(cpu);
		break;
	case CPU_DEAD:
		class_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_class_device_create(i);
		if (err != 0)
			goto out_class;
	}
	register_cpu_notifier(&msr_class_cpu_notifier);

	err = 0;
	goto out;

out_class:
	i = 0;
	for_each_online_cpu(i)
		class_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)
		class_device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
	class_destroy(msr_class);
	unregister_chrdev(MSR_MAJOR, "cpu/msr");
	unregister_cpu_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>
	27	#include <linux/config.h>
	28
	29	#include <linux/types.h>
	30	#include <linux/errno.h>
	31	#include <linux/fcntl.h>
	32	#include <linux/init.h>
	33	#include <linux/poll.h>
	34	#include <linux/smp.h>
	35	#include <linux/smp_lock.h>
	36	#include <linux/major.h>
	37	#include <linux/fs.h>
	38	#include <linux/device.h>
	39	#include <linux/cpu.h>
	40	#include <linux/notifier.h>
	41
	42	#include <asm/processor.h>
	43	#include <asm/msr.h>
	44	#include <asm/uaccess.h>
	45	#include <asm/system.h>
	46
8874b414	47	static struct class *msr_class;
1da177e4	48
1da177e4 LT	49	static inline int wrmsr_eio(u32 reg, u32 eax, u32 edx)
	50	{
	51	int err;
	52
f2ab4461 ZA	53	err = wrmsr_safe(reg, eax, edx);
	54	if (err)
	55	err = -EIO;
1da177e4 LT	56	return err;
	57	}
	58
	59	static inline int rdmsr_eio(u32 reg, u32 eax, u32 edx)
	60	{
	61	int err;
	62
f2ab4461 ZA	63	err = rdmsr_safe(reg, eax, edx);
	64	if (err)
	65	err = -EIO;
1da177e4 LT	66	return err;
	67	}
	68
	69	#ifdef CONFIG_SMP
	70
	71	struct msr_command {
	72	int cpu;
	73	int err;
	74	u32 reg;
	75	u32 data[2];
	76	};
	77
	78	static void msr_smp_wrmsr(void *cmd_block)
	79	{
	80	struct msr_command cmd = (struct msr_command )cmd_block;
	81
	82	if (cmd->cpu == smp_processor_id())
	83	cmd->err = wrmsr_eio(cmd->reg, cmd->data[0], cmd->data[1]);
	84	}
	85
	86	static void msr_smp_rdmsr(void *cmd_block)
	87	{
	88	struct msr_command cmd = (struct msr_command )cmd_block;
	89
	90	if (cmd->cpu == smp_processor_id())
	91	cmd->err = rdmsr_eio(cmd->reg, &cmd->data[0], &cmd->data[1]);
	92	}
	93
	94	static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
	95	{
	96	struct msr_command cmd;
	97	int ret;
	98
	99	preempt_disable();
	100	if (cpu == smp_processor_id()) {
	101	ret = wrmsr_eio(reg, eax, edx);
	102	} else {
	103	cmd.cpu = cpu;
	104	cmd.reg = reg;
	105	cmd.data[0] = eax;
	106	cmd.data[1] = edx;
	107
	108	smp_call_function(msr_smp_wrmsr, &cmd, 1, 1);
	109	ret = cmd.err;
	110	}
	111	preempt_enable();
	112	return ret;
	113	}
	114
	115	static inline int do_rdmsr(int cpu, u32 reg, u32 * eax, u32 * edx)
	116	{
	117	struct msr_command cmd;
	118	int ret;
	119
	120	preempt_disable();
	121	if (cpu == smp_processor_id()) {
	122	ret = rdmsr_eio(reg, eax, edx);
	123	} else {
	124	cmd.cpu = cpu;
	125	cmd.reg = reg;
	126
	127	smp_call_function(msr_smp_rdmsr, &cmd, 1, 1);
	128
	129	*eax = cmd.data[0];
130	*edx = cmd.data[1];
131
132	ret = cmd.err;
133	}
134	preempt_enable();
135	return ret;
136	}
137
138	#else /* ! CONFIG_SMP */
139
140	static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
141	{
142	return wrmsr_eio(reg, eax, edx);
143	}
144
145	static inline int do_rdmsr(int cpu, u32 reg, u32 eax, u32 edx)
146	{
147	return rdmsr_eio(reg, eax, edx);
148	}
149
150	#endif /* ! CONFIG_SMP */
151
152	static loff_t msr_seek(struct file *file, loff_t offset, int orig)
153	{
154	loff_t ret = -EINVAL;
155
156	lock_kernel();
157	switch (orig) {
158	case 0:
159	file->f_pos = offset;
160	ret = file->f_pos;
161	break;
162	case 1:
163	file->f_pos += offset;
164	ret = file->f_pos;
165	}
166	unlock_kernel();
167	return ret;
168	}
169
170	static ssize_t msr_read(struct file file, char __user buf,
171	size_t count, loff_t * ppos)
172	{
173	u32 __user tmp = (u32 __user ) buf;
174	u32 data[2];
1da177e4 LT	175	u32 reg = *ppos;
	176	int cpu = iminor(file->f_dentry->d_inode);
	177	int err;
	178
	179	if (count % 8)
	180	return -EINVAL; /* Invalid chunk size */
	181
6926d570	182	for (; count; count -= 8) {
1da177e4 LT	183	err = do_rdmsr(cpu, reg, &data[0], &data[1]);
	184	if (err)
	185	return err;
	186	if (copy_to_user(tmp, &data, 8))
	187	return -EFAULT;
	188	tmp += 2;
	189	}
	190
	191	return ((char __user *)tmp) - buf;
	192	}
	193
	194	static ssize_t msr_write(struct file file, const char __user buf,
	195	size_t count, loff_t *ppos)
	196	{
	197	const u32 __user tmp = (const u32 __user )buf;
	198	u32 data[2];
	199	size_t rv;
	200	u32 reg = *ppos;
	201	int cpu = iminor(file->f_dentry->d_inode);
	202	int err;
	203
	204	if (count % 8)
	205	return -EINVAL; /* Invalid chunk size */
	206
	207	for (rv = 0; count; count -= 8) {
	208	if (copy_from_user(&data, tmp, 8))
	209	return -EFAULT;
	210	err = do_wrmsr(cpu, reg, data[0], data[1]);
	211	if (err)
	212	return err;
	213	tmp += 2;
	214	}
	215
	216	return ((char __user *)tmp) - buf;
	217	}
	218
	219	static int msr_open(struct inode inode, struct file file)
	220	{
	221	unsigned int cpu = iminor(file->f_dentry->d_inode);
	222	struct cpuinfo_x86 *c = &(cpu_data)[cpu];
	223
	224	if (cpu >= NR_CPUS \|\| !cpu_online(cpu))
	225	return -ENXIO; /* No such CPU */
	226	if (!cpu_has(c, X86_FEATURE_MSR))
	227	return -EIO; /* MSR not supported */
	228
	229	return 0;
	230	}
	231
	232	/*
	233	* File operations we support
	234	*/
	235	static struct file_operations msr_fops = {
	236	.owner = THIS_MODULE,
	237	.llseek = msr_seek,
	238	.read = msr_read,
	239	.write = msr_write,
	240	.open = msr_open,
	241	};
	242
8874b414	243	static int msr_class_device_create(int i)
1da177e4 LT	244	{
	245	int err = 0;
	246	struct class_device *class_err;
	247
53f46542	248	class_err = class_device_create(msr_class, NULL, MKDEV(MSR_MAJOR, i), NULL, "msr%d",i);
1da177e4 LT	249	if (IS_ERR(class_err))
	250	err = PTR_ERR(class_err);
	251	return err;
	252	}
	253
efe87d2b	254	static int msr_class_cpu_callback(struct notifier_block nfb, unsigned long action, void hcpu)
1da177e4 LT	255	{
	256	unsigned int cpu = (unsigned long)hcpu;
	257
	258	switch (action) {
	259	case CPU_ONLINE:
8874b414	260	msr_class_device_create(cpu);
1da177e4 LT	261	break;
1da177e4 LT	262	case CPU_DEAD:
8874b414	263	class_device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
1da177e4 LT	264	break;
	265	}
	266	return NOTIFY_OK;
	267	}
	268
74b85f37	269	static struct notifier_block __cpuinitdata msr_class_cpu_notifier =
1da177e4 LT	270	{
	271	.notifier_call = msr_class_cpu_callback,
	272	};
	273
	274	static int __init msr_init(void)
	275	{
	276	int i, err = 0;
	277	i = 0;
	278
	279	if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
	280	printk(KERN_ERR "msr: unable to get major %d for msr\n",
	281	MSR_MAJOR);
	282	err = -EBUSY;
	283	goto out;
	284	}
8874b414	285	msr_class = class_create(THIS_MODULE, "msr");
1da177e4 LT	286	if (IS_ERR(msr_class)) {
	287	err = PTR_ERR(msr_class);
	288	goto out_chrdev;
	289	}
	290	for_each_online_cpu(i) {
8874b414	291	err = msr_class_device_create(i);
1da177e4 LT	292	if (err != 0)
	293	goto out_class;
	294	}
	295	register_cpu_notifier(&msr_class_cpu_notifier);
	296
	297	err = 0;
	298	goto out;
	299
	300	out_class:
	301	i = 0;
	302	for_each_online_cpu(i)
8874b414	303	class_device_destroy(msr_class, MKDEV(MSR_MAJOR, i));
8874b414	304	class_destroy(msr_class);
1da177e4 LT	305	out_chrdev:
	306	unregister_chrdev(MSR_MAJOR, "cpu/msr");
	307	out:
	308	return err;
	309	}
	310
	311	static void __exit msr_exit(void)
	312	{
	313	int cpu = 0;
	314	for_each_online_cpu(cpu)
8874b414	315	class_device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
8874b414	316	class_destroy(msr_class);
1da177e4 LT	317	unregister_chrdev(MSR_MAJOR, "cpu/msr");
	318	unregister_cpu_notifier(&msr_class_cpu_notifier);
	319	}
	320
	321	module_init(msr_init);
	322	module_exit(msr_exit)
	323
	324	MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
	325	MODULE_DESCRIPTION("x86 generic MSR driver");
	326	MODULE_LICENSE("GPL");