![Alexey Dobriyan](/assets/img/avatar_default.png)
It will execure cpuid only on the cpu we need. Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Signed-off-by: Andi Kleen <ak@suse.de>
241 lines
5.1 KiB
C
241 lines
5.1 KiB
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:
|
|
cpuid_device_create(cpu);
|
|
break;
|
|
case CPU_DEAD:
|
|
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");
|