[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 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_path.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];
	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 = 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_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 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:
		msr_device_create(cpu);
		break;
	case CPU_DEAD:
		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 inline int wrmsr_eio(u32 reg, u32 eax, u32 edx)
	49	{
	50	int err;
	51
f2ab4461 ZA	52	err = wrmsr_safe(reg, eax, edx);
	53	if (err)
	54	err = -EIO;
1da177e4 LT	55	return err;
	56	}
	57
	58	static inline int rdmsr_eio(u32 reg, u32 eax, u32 edx)
	59	{
	60	int err;
	61
f2ab4461 ZA	62	err = rdmsr_safe(reg, eax, edx);
	63	if (err)
	64	err = -EIO;
1da177e4 LT	65	return err;
	66	}
	67
	68	#ifdef CONFIG_SMP
	69
	70	struct msr_command {
	71	int cpu;
	72	int err;
	73	u32 reg;
	74	u32 data[2];
	75	};
	76
	77	static void msr_smp_wrmsr(void *cmd_block)
	78	{
	79	struct msr_command cmd = (struct msr_command )cmd_block;
	80
	81	if (cmd->cpu == smp_processor_id())
	82	cmd->err = wrmsr_eio(cmd->reg, cmd->data[0], cmd->data[1]);
	83	}
	84
	85	static void msr_smp_rdmsr(void *cmd_block)
	86	{
	87	struct msr_command cmd = (struct msr_command )cmd_block;
	88
	89	if (cmd->cpu == smp_processor_id())
	90	cmd->err = rdmsr_eio(cmd->reg, &cmd->data[0], &cmd->data[1]);
	91	}
	92
	93	static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
	94	{
	95	struct msr_command cmd;
	96	int ret;
	97
	98	preempt_disable();
	99	if (cpu == smp_processor_id()) {
	100	ret = wrmsr_eio(reg, eax, edx);
	101	} else {
	102	cmd.cpu = cpu;
	103	cmd.reg = reg;
	104	cmd.data[0] = eax;
	105	cmd.data[1] = edx;
	106
	107	smp_call_function(msr_smp_wrmsr, &cmd, 1, 1);
	108	ret = cmd.err;
	109	}
	110	preempt_enable();
	111	return ret;
	112	}
	113
	114	static inline int do_rdmsr(int cpu, u32 reg, u32 * eax, u32 * edx)
	115	{
	116	struct msr_command cmd;
	117	int ret;
	118
	119	preempt_disable();
	120	if (cpu == smp_processor_id()) {
	121	ret = rdmsr_eio(reg, eax, edx);
	122	} else {
	123	cmd.cpu = cpu;
	124	cmd.reg = reg;
	125
	126	smp_call_function(msr_smp_rdmsr, &cmd, 1, 1);
	127
	128	*eax = cmd.data[0];
129	*edx = cmd.data[1];
130
131	ret = cmd.err;
132	}
133	preempt_enable();
134	return ret;
135	}
136
137	#else /* ! CONFIG_SMP */
138
139	static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx)
140	{
141	return wrmsr_eio(reg, eax, edx);
142	}
143
144	static inline int do_rdmsr(int cpu, u32 reg, u32 eax, u32 edx)
145	{
146	return rdmsr_eio(reg, eax, edx);
147	}
148
149	#endif /* ! CONFIG_SMP */
150
151	static loff_t msr_seek(struct file *file, loff_t offset, int orig)
152	{
153	loff_t ret = -EINVAL;
154
155	lock_kernel();
156	switch (orig) {
157	case 0:
158	file->f_pos = offset;
159	ret = file->f_pos;
160	break;
161	case 1:
162	file->f_pos += offset;
163	ret = file->f_pos;
164	}
165	unlock_kernel();
166	return ret;
167	}
168
169	static ssize_t msr_read(struct file file, char __user buf,
170	size_t count, loff_t * ppos)
171	{
172	u32 __user tmp = (u32 __user ) buf;
173	u32 data[2];
1da177e4	174	u32 reg = *ppos;
aab4c5a5	175	int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	176	int err;
	177
	178	if (count % 8)
	179	return -EINVAL; /* Invalid chunk size */
	180
6926d570	181	for (; count; count -= 8) {
1da177e4 LT	182	err = do_rdmsr(cpu, reg, &data[0], &data[1]);
	183	if (err)
	184	return err;
	185	if (copy_to_user(tmp, &data, 8))
	186	return -EFAULT;
	187	tmp += 2;
	188	}
	189
	190	return ((char __user *)tmp) - buf;
	191	}
	192
	193	static ssize_t msr_write(struct file file, const char __user buf,
	194	size_t count, loff_t *ppos)
	195	{
	196	const u32 __user tmp = (const u32 __user )buf;
	197	u32 data[2];
1da177e4	198	u32 reg = *ppos;
aab4c5a5	199	int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	200	int err;
	201
	202	if (count % 8)
	203	return -EINVAL; /* Invalid chunk size */
	204
f475ff35	205	for (; count; count -= 8) {
1da177e4 LT	206	if (copy_from_user(&data, tmp, 8))
	207	return -EFAULT;
	208	err = do_wrmsr(cpu, reg, data[0], data[1]);
	209	if (err)
	210	return err;
	211	tmp += 2;
	212	}
	213
	214	return ((char __user *)tmp) - buf;
	215	}
	216
	217	static int msr_open(struct inode inode, struct file file)
	218	{
aab4c5a5	219	unsigned int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	220	struct cpuinfo_x86 *c = &(cpu_data)[cpu];
	221
	222	if (cpu >= NR_CPUS \|\| !cpu_online(cpu))
	223	return -ENXIO; /* No such CPU */
	224	if (!cpu_has(c, X86_FEATURE_MSR))
	225	return -EIO; /* MSR not supported */
	226
	227	return 0;
	228	}
	229
	230	/*
	231	* File operations we support
	232	*/
	233	static struct file_operations msr_fops = {
	234	.owner = THIS_MODULE,
	235	.llseek = msr_seek,
	236	.read = msr_read,
	237	.write = msr_write,
	238	.open = msr_open,
	239	};
	240
a271aaf1	241	static int msr_device_create(int i)
1da177e4 LT	242	{
1da177e4 LT	243	int err = 0;
a271aaf1	244	struct device *dev;
1da177e4	245
a271aaf1 GKH	246	dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, i), "msr%d",i);
	247	if (IS_ERR(dev))
	248	err = PTR_ERR(dev);
1da177e4 LT	249	return err;
	250	}
	251
e09793bb AM	252	static int msr_class_cpu_callback(struct notifier_block *nfb,
e09793bb AM	253	unsigned long action, void *hcpu)
1da177e4 LT	254	{
	255	unsigned int cpu = (unsigned long)hcpu;
	256
	257	switch (action) {
	258	case CPU_ONLINE:
a271aaf1	259	msr_device_create(cpu);
1da177e4 LT	260	break;
1da177e4 LT	261	case CPU_DEAD:
a271aaf1	262	device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
1da177e4 LT	263	break;
	264	}
	265	return NOTIFY_OK;
	266	}
	267
74b85f37	268	static struct notifier_block __cpuinitdata msr_class_cpu_notifier =
1da177e4 LT	269	{
	270	.notifier_call = msr_class_cpu_callback,
	271	};
	272
	273	static int __init msr_init(void)
	274	{
	275	int i, err = 0;
	276	i = 0;
	277
	278	if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
	279	printk(KERN_ERR "msr: unable to get major %d for msr\n",
	280	MSR_MAJOR);
	281	err = -EBUSY;
	282	goto out;
	283	}
8874b414	284	msr_class = class_create(THIS_MODULE, "msr");
1da177e4 LT	285	if (IS_ERR(msr_class)) {
	286	err = PTR_ERR(msr_class);
	287	goto out_chrdev;
	288	}
	289	for_each_online_cpu(i) {
a271aaf1	290	err = msr_device_create(i);
1da177e4 LT	291	if (err != 0)
	292	goto out_class;
	293	}
e09793bb	294	register_hotcpu_notifier(&msr_class_cpu_notifier);
1da177e4 LT	295
	296	err = 0;
	297	goto out;
	298
	299	out_class:
	300	i = 0;
	301	for_each_online_cpu(i)
a271aaf1	302	device_destroy(msr_class, MKDEV(MSR_MAJOR, i));
8874b414	303	class_destroy(msr_class);
1da177e4 LT	304	out_chrdev:
	305	unregister_chrdev(MSR_MAJOR, "cpu/msr");
	306	out:
	307	return err;
	308	}
	309
	310	static void __exit msr_exit(void)
	311	{
	312	int cpu = 0;
	313	for_each_online_cpu(cpu)
a271aaf1	314	device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
8874b414	315	class_destroy(msr_class);
1da177e4	316	unregister_chrdev(MSR_MAJOR, "cpu/msr");
e09793bb	317	unregister_hotcpu_notifier(&msr_class_cpu_notifier);
1da177e4 LT	318	}
	319
	320	module_init(msr_init);
	321	module_exit(msr_exit)
	322
	323	MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
	324	MODULE_DESCRIPTION("x86 generic MSR driver");
	325	MODULE_LICENSE("GPL");