[mirror_ubuntu-artful-kernel.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/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 *cpuid_class;

#ifdef CONFIG_SMP

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

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

	if (cmd->cpu == smp_processor_id())
		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.cpu = cpu;
		cmd.reg = reg;
		cmd.data = data;

		smp_call_function(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_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_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 struct file_operations cpuid_fops = {
	.owner = THIS_MODULE,
	.llseek = cpuid_seek,
	.read = cpuid_read,
	.open = cpuid_open,
};

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

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

#ifdef CONFIG_HOTPLUG_CPU
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:
		cpuid_class_device_create(cpu);
		break;
	case CPU_DEAD:
		class_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,
};
#endif /* !CONFIG_HOTPLUG_CPU */

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_class_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) {
		class_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)
		class_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>
	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 *cpuid_class;
1da177e4 LT	48
	49	#ifdef CONFIG_SMP
	50
	51	struct cpuid_command {
	52	int cpu;
	53	u32 reg;
	54	u32 *data;
	55	};
	56
	57	static void cpuid_smp_cpuid(void *cmd_block)
	58	{
	59	struct cpuid_command cmd = (struct cpuid_command )cmd_block;
	60
	61	if (cmd->cpu == smp_processor_id())
	62	cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2],
	63	&cmd->data[3]);
	64	}
	65
	66	static inline void do_cpuid(int cpu, u32 reg, u32 * data)
	67	{
	68	struct cpuid_command cmd;
	69
	70	preempt_disable();
	71	if (cpu == smp_processor_id()) {
	72	cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
	73	} else {
	74	cmd.cpu = cpu;
	75	cmd.reg = reg;
	76	cmd.data = data;
	77
	78	smp_call_function(cpuid_smp_cpuid, &cmd, 1, 1);
	79	}
	80	preempt_enable();
	81	}
	82	#else /* ! CONFIG_SMP */
	83
	84	static inline void do_cpuid(int cpu, u32 reg, u32 * data)
	85	{
	86	cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
	87	}
	88
	89	#endif /* ! CONFIG_SMP */
	90
	91	static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
	92	{
	93	loff_t ret;
	94
	95	lock_kernel();
	96
	97	switch (orig) {
	98	case 0:
	99	file->f_pos = offset;
	100	ret = file->f_pos;
	101	break;
	102	case 1:
	103	file->f_pos += offset;
	104	ret = file->f_pos;
	105	break;
	106	default:
	107	ret = -EINVAL;
	108	}
	109
	110	unlock_kernel();
	111	return ret;
112	}
113
114	static ssize_t cpuid_read(struct file file, char __user buf,
115	size_t count, loff_t * ppos)
116	{
117	char __user *tmp = buf;
118	u32 data[4];
1da177e4 LT	119	u32 reg = *ppos;
	120	int cpu = iminor(file->f_dentry->d_inode);
	121
	122	if (count % 16)
	123	return -EINVAL; /* Invalid chunk size */
	124
6b7f430e	125	for (; count; count -= 16) {
1da177e4 LT	126	do_cpuid(cpu, reg, data);
	127	if (copy_to_user(tmp, &data, 16))
	128	return -EFAULT;
	129	tmp += 16;
	130	*ppos = reg++;
	131	}
	132
	133	return tmp - buf;
	134	}
	135
	136	static int cpuid_open(struct inode inode, struct file file)
	137	{
	138	unsigned int cpu = iminor(file->f_dentry->d_inode);
	139	struct cpuinfo_x86 *c = &(cpu_data)[cpu];
	140
	141	if (cpu >= NR_CPUS \|\| !cpu_online(cpu))
	142	return -ENXIO; /* No such CPU */
	143	if (c->cpuid_level < 0)
	144	return -EIO; /* CPUID not supported */
	145
	146	return 0;
	147	}
	148
	149	/*
	150	* File operations we support
	151	*/
	152	static struct file_operations cpuid_fops = {
	153	.owner = THIS_MODULE,
	154	.llseek = cpuid_seek,
	155	.read = cpuid_read,
	156	.open = cpuid_open,
	157	};
	158
8874b414	159	static int cpuid_class_device_create(int i)
1da177e4 LT	160	{
	161	int err = 0;
	162	struct class_device *class_err;
	163
53f46542	164	class_err = class_device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, i), NULL, "cpu%d",i);
1da177e4 LT	165	if (IS_ERR(class_err))
	166	err = PTR_ERR(class_err);
	167	return err;
	168	}
	169
b6a7c79a	170	#ifdef CONFIG_HOTPLUG_CPU
efe87d2b	171	static int cpuid_class_cpu_callback(struct notifier_block nfb, unsigned long action, void hcpu)
1da177e4 LT	172	{
	173	unsigned int cpu = (unsigned long)hcpu;
	174
	175	switch (action) {
	176	case CPU_ONLINE:
8874b414	177	cpuid_class_device_create(cpu);
1da177e4 LT	178	break;
1da177e4 LT	179	case CPU_DEAD:
8874b414	180	class_device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
1da177e4 LT	181	break;
	182	}
	183	return NOTIFY_OK;
	184	}
	185
74b85f37	186	static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier =
1da177e4 LT	187	{
	188	.notifier_call = cpuid_class_cpu_callback,
	189	};
b6a7c79a	190	#endif /* !CONFIG_HOTPLUG_CPU */
1da177e4 LT	191
	192	static int __init cpuid_init(void)
	193	{
	194	int i, err = 0;
	195	i = 0;
	196
	197	if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
	198	printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
	199	CPUID_MAJOR);
	200	err = -EBUSY;
	201	goto out;
	202	}
8874b414	203	cpuid_class = class_create(THIS_MODULE, "cpuid");
1da177e4 LT	204	if (IS_ERR(cpuid_class)) {
	205	err = PTR_ERR(cpuid_class);
	206	goto out_chrdev;
	207	}
	208	for_each_online_cpu(i) {
8874b414	209	err = cpuid_class_device_create(i);
1da177e4 LT	210	if (err != 0)
	211	goto out_class;
	212	}
b6a7c79a	213	register_hotcpu_notifier(&cpuid_class_cpu_notifier);
1da177e4 LT	214
	215	err = 0;
	216	goto out;
	217
	218	out_class:
	219	i = 0;
	220	for_each_online_cpu(i) {
8874b414	221	class_device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, i));
1da177e4	222	}
8874b414	223	class_destroy(cpuid_class);
1da177e4 LT	224	out_chrdev:
	225	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
	226	out:
	227	return err;
	228	}
	229
	230	static void __exit cpuid_exit(void)
	231	{
	232	int cpu = 0;
	233
	234	for_each_online_cpu(cpu)
8874b414 GKH	235	class_device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
8874b414 GKH	236	class_destroy(cpuid_class);
1da177e4	237	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
b6a7c79a	238	unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
1da177e4 LT	239	}
	240
	241	module_init(cpuid_init);
	242	module_exit(cpuid_exit);
	243
	244	MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
	245	MODULE_DESCRIPTION("x86 generic CPUID driver");
	246	MODULE_LICENSE("GPL");