[deliverable/linux.git] / arch / i386 / kernel / cpuid.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.
 *
 * ----------------------------------------------------------------------- */

/*
 * cpuid.c
 *
 * x86 CPUID access device
 *
 * This device is accessed by lseek() to the appropriate CPUID level
 * and then read in chunks of 16 bytes.  A larger size means multiple
 * reads of consecutive levels.
 *
 * This driver uses /dev/cpu/%d/cpuid 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/major.h>
#include <linux/fs.h>
#include <linux/smp_lock.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 *cpuid_class;

#ifdef CONFIG_SMP

struct cpuid_command {
	u32 reg;
	u32 *data;
};

static void cpuid_smp_cpuid(void *cmd_block)
{
	struct cpuid_command *cmd = (struct cpuid_command *)cmd_block;

	cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2],
		      &cmd->data[3]);
}

static inline void do_cpuid(int cpu, u32 reg, u32 * data)
{
	struct cpuid_command cmd;

	preempt_disable();
	if (cpu == smp_processor_id()) {
		cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
	} else {
		cmd.reg = reg;
		cmd.data = data;

		smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1);
	}
	preempt_enable();
}
#else				/* ! CONFIG_SMP */

static inline void do_cpuid(int cpu, u32 reg, u32 * data)
{
	cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
}

#endif				/* ! CONFIG_SMP */

static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
{
	loff_t ret;

	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;
		break;
	default:
		ret = -EINVAL;
	}

	unlock_kernel();
	return ret;
}

static ssize_t cpuid_read(struct file *file, char __user *buf,
			  size_t count, loff_t * ppos)
{
	char __user *tmp = buf;
	u32 data[4];
	u32 reg = *ppos;
	int cpu = iminor(file->f_path.dentry->d_inode);

	if (count % 16)
		return -EINVAL;	/* Invalid chunk size */

	for (; count; count -= 16) {
		do_cpuid(cpu, reg, data);
		if (copy_to_user(tmp, &data, 16))
			return -EFAULT;
		tmp += 16;
		*ppos = reg++;
	}

	return tmp - buf;
}

static int cpuid_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 (c->cpuid_level < 0)
		return -EIO;	/* CPUID not supported */

	return 0;
}

/*
 * File operations we support
 */
static const struct file_operations cpuid_fops = {
	.owner = THIS_MODULE,
	.llseek = cpuid_seek,
	.read = cpuid_read,
	.open = cpuid_open,
};

static int cpuid_device_create(int i)
{
	int err = 0;
	struct device *dev;

	dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, i), "cpu%d",i);
	if (IS_ERR(dev))
		err = PTR_ERR(dev);
	return err;
}

static int cpuid_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:
		cpuid_device_create(cpu);
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier =
{
	.notifier_call = cpuid_class_cpu_callback,
};

static int __init cpuid_init(void)
{
	int i, err = 0;
	i = 0;

	if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
		printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
		       CPUID_MAJOR);
		err = -EBUSY;
		goto out;
	}
	cpuid_class = class_create(THIS_MODULE, "cpuid");
	if (IS_ERR(cpuid_class)) {
		err = PTR_ERR(cpuid_class);
		goto out_chrdev;
	}
	for_each_online_cpu(i) {
		err = cpuid_device_create(i);
		if (err != 0) 
			goto out_class;
	}
	register_hotcpu_notifier(&cpuid_class_cpu_notifier);

	err = 0;
	goto out;

out_class:
	i = 0;
	for_each_online_cpu(i) {
		device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, i));
	}
	class_destroy(cpuid_class);
out_chrdev:
	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");	
out:
	return err;
}

static void __exit cpuid_exit(void)
{
	int cpu = 0;

	for_each_online_cpu(cpu)
		device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
	class_destroy(cpuid_class);
	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
	unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
}

module_init(cpuid_init);
module_exit(cpuid_exit);

MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
MODULE_DESCRIPTION("x86 generic CPUID 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	* cpuid.c
	15	*
	16	* x86 CPUID access device
	17	*
	18	* This device is accessed by lseek() to the appropriate CPUID level
	19	* and then read in chunks of 16 bytes. A larger size means multiple
	20	* reads of consecutive levels.
	21	*
	22	* This driver uses /dev/cpu/%d/cpuid 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/major.h>
	35	#include <linux/fs.h>
	36	#include <linux/smp_lock.h>
1da177e4 LT	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 *cpuid_class;
1da177e4 LT	47
	48	#ifdef CONFIG_SMP
	49
	50	struct cpuid_command {
1da177e4 LT	51	u32 reg;
	52	u32 *data;
	53	};
	54
	55	static void cpuid_smp_cpuid(void *cmd_block)
	56	{
	57	struct cpuid_command cmd = (struct cpuid_command )cmd_block;
	58
ad4e680f	59	cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2],
1da177e4 LT	60	&cmd->data[3]);
	61	}
	62
	63	static inline void do_cpuid(int cpu, u32 reg, u32 * data)
	64	{
	65	struct cpuid_command cmd;
	66
	67	preempt_disable();
	68	if (cpu == smp_processor_id()) {
	69	cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
	70	} else {
1da177e4 LT	71	cmd.reg = reg;
	72	cmd.data = data;
	73
ad4e680f	74	smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1);
1da177e4 LT	75	}
	76	preempt_enable();
	77	}
	78	#else /* ! CONFIG_SMP */
	79
	80	static inline void do_cpuid(int cpu, u32 reg, u32 * data)
	81	{
	82	cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
	83	}
	84
	85	#endif /* ! CONFIG_SMP */
	86
	87	static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
	88	{
	89	loff_t ret;
	90
	91	lock_kernel();
	92
	93	switch (orig) {
	94	case 0:
	95	file->f_pos = offset;
	96	ret = file->f_pos;
	97	break;
	98	case 1:
	99	file->f_pos += offset;
	100	ret = file->f_pos;
	101	break;
	102	default:
	103	ret = -EINVAL;
	104	}
	105
	106	unlock_kernel();
	107	return ret;
	108	}
	109
	110	static ssize_t cpuid_read(struct file file, char __user buf,
	111	size_t count, loff_t * ppos)
	112	{
	113	char __user *tmp = buf;
	114	u32 data[4];
1da177e4	115	u32 reg = *ppos;
aab4c5a5	116	int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	117
	118	if (count % 16)
	119	return -EINVAL; /* Invalid chunk size */
	120
6b7f430e	121	for (; count; count -= 16) {
1da177e4 LT	122	do_cpuid(cpu, reg, data);
	123	if (copy_to_user(tmp, &data, 16))
	124	return -EFAULT;
	125	tmp += 16;
	126	*ppos = reg++;
	127	}
	128
	129	return tmp - buf;
	130	}
	131
	132	static int cpuid_open(struct inode inode, struct file file)
	133	{
aab4c5a5	134	unsigned int cpu = iminor(file->f_path.dentry->d_inode);
1da177e4 LT	135	struct cpuinfo_x86 *c = &(cpu_data)[cpu];
	136
	137	if (cpu >= NR_CPUS \|\| !cpu_online(cpu))
	138	return -ENXIO; /* No such CPU */
	139	if (c->cpuid_level < 0)
	140	return -EIO; /* CPUID not supported */
	141
	142	return 0;
	143	}
	144
	145	/*
	146	* File operations we support
	147	*/
5dfe4c96	148	static const struct file_operations cpuid_fops = {
1da177e4 LT	149	.owner = THIS_MODULE,
	150	.llseek = cpuid_seek,
	151	.read = cpuid_read,
	152	.open = cpuid_open,
	153	};
	154
07accdc1	155	static int cpuid_device_create(int i)
1da177e4 LT	156	{
1da177e4 LT	157	int err = 0;
07accdc1	158	struct device *dev;
1da177e4	159
07accdc1 GKH	160	dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, i), "cpu%d",i);
	161	if (IS_ERR(dev))
	162	err = PTR_ERR(dev);
1da177e4 LT	163	return err;
	164	}
	165
efe87d2b	166	static int cpuid_class_cpu_callback(struct notifier_block nfb, unsigned long action, void hcpu)
1da177e4 LT	167	{
	168	unsigned int cpu = (unsigned long)hcpu;
	169
	170	switch (action) {
	171	case CPU_ONLINE:
8bb78442	172	case CPU_ONLINE_FROZEN:
07accdc1	173	cpuid_device_create(cpu);
1da177e4 LT	174	break;
1da177e4 LT	175	case CPU_DEAD:
8bb78442	176	case CPU_DEAD_FROZEN:
07accdc1	177	device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
1da177e4 LT	178	break;
	179	}
	180	return NOTIFY_OK;
	181	}
	182
74b85f37	183	static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier =
1da177e4 LT	184	{
	185	.notifier_call = cpuid_class_cpu_callback,
	186	};
	187
	188	static int __init cpuid_init(void)
	189	{
	190	int i, err = 0;
	191	i = 0;
	192
	193	if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
	194	printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
	195	CPUID_MAJOR);
	196	err = -EBUSY;
	197	goto out;
	198	}
8874b414	199	cpuid_class = class_create(THIS_MODULE, "cpuid");
1da177e4 LT	200	if (IS_ERR(cpuid_class)) {
	201	err = PTR_ERR(cpuid_class);
	202	goto out_chrdev;
	203	}
	204	for_each_online_cpu(i) {
07accdc1	205	err = cpuid_device_create(i);
1da177e4 LT	206	if (err != 0)
	207	goto out_class;
	208	}
b6a7c79a	209	register_hotcpu_notifier(&cpuid_class_cpu_notifier);
1da177e4 LT	210
	211	err = 0;
	212	goto out;
	213
	214	out_class:
	215	i = 0;
	216	for_each_online_cpu(i) {
07accdc1	217	device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, i));
1da177e4	218	}
8874b414	219	class_destroy(cpuid_class);
1da177e4 LT	220	out_chrdev:
	221	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
	222	out:
	223	return err;
	224	}
	225
	226	static void __exit cpuid_exit(void)
	227	{
	228	int cpu = 0;
	229
	230	for_each_online_cpu(cpu)
07accdc1	231	device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
8874b414	232	class_destroy(cpuid_class);
1da177e4	233	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
b6a7c79a	234	unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
1da177e4 LT	235	}
	236
	237	module_init(cpuid_init);
	238	module_exit(cpuid_exit);
	239
	240	MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
	241	MODULE_DESCRIPTION("x86 generic CPUID driver");
	242	MODULE_LICENSE("GPL");