247 lines
5.3 KiB
C
247 lines
5.3 KiB
C
![]() |
/* ----------------------------------------------------------------------- *
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*
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* Copyright 2000 H. Peter Anvin - All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
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* USA; either version 2 of the License, or (at your option) any later
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* version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* cpuid.c
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*
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* x86 CPUID access device
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*
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* This device is accessed by lseek() to the appropriate CPUID level
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* and then read in chunks of 16 bytes. A larger size means multiple
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* reads of consecutive levels.
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*
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* This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on
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* an SMP box will direct the access to CPU %d.
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*/
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#include <linux/module.h>
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#include <linux/config.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/fcntl.h>
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#include <linux/init.h>
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#include <linux/poll.h>
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#include <linux/smp.h>
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#include <linux/major.h>
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#include <linux/fs.h>
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#include <linux/smp_lock.h>
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#include <linux/fs.h>
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#include <linux/device.h>
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#include <linux/cpu.h>
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#include <linux/notifier.h>
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#include <asm/processor.h>
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#include <asm/msr.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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static struct class_simple *cpuid_class;
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#ifdef CONFIG_SMP
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struct cpuid_command {
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int cpu;
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u32 reg;
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u32 *data;
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};
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static void cpuid_smp_cpuid(void *cmd_block)
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{
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struct cpuid_command *cmd = (struct cpuid_command *)cmd_block;
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if (cmd->cpu == smp_processor_id())
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cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2],
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&cmd->data[3]);
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}
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static inline void do_cpuid(int cpu, u32 reg, u32 * data)
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{
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struct cpuid_command cmd;
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preempt_disable();
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if (cpu == smp_processor_id()) {
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cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
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} else {
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cmd.cpu = cpu;
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cmd.reg = reg;
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cmd.data = data;
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smp_call_function(cpuid_smp_cpuid, &cmd, 1, 1);
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}
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preempt_enable();
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}
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#else /* ! CONFIG_SMP */
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static inline void do_cpuid(int cpu, u32 reg, u32 * data)
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{
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cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
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}
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#endif /* ! CONFIG_SMP */
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static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
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{
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loff_t ret;
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lock_kernel();
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switch (orig) {
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case 0:
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file->f_pos = offset;
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ret = file->f_pos;
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break;
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case 1:
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file->f_pos += offset;
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ret = file->f_pos;
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break;
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default:
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ret = -EINVAL;
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}
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unlock_kernel();
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return ret;
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}
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static ssize_t cpuid_read(struct file *file, char __user *buf,
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size_t count, loff_t * ppos)
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{
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char __user *tmp = buf;
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u32 data[4];
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size_t rv;
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u32 reg = *ppos;
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int cpu = iminor(file->f_dentry->d_inode);
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if (count % 16)
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return -EINVAL; /* Invalid chunk size */
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for (rv = 0; count; count -= 16) {
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do_cpuid(cpu, reg, data);
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if (copy_to_user(tmp, &data, 16))
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return -EFAULT;
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tmp += 16;
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*ppos = reg++;
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}
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return tmp - buf;
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}
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static int cpuid_open(struct inode *inode, struct file *file)
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{
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unsigned int cpu = iminor(file->f_dentry->d_inode);
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struct cpuinfo_x86 *c = &(cpu_data)[cpu];
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if (cpu >= NR_CPUS || !cpu_online(cpu))
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return -ENXIO; /* No such CPU */
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if (c->cpuid_level < 0)
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return -EIO; /* CPUID not supported */
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return 0;
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}
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/*
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* File operations we support
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*/
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static struct file_operations cpuid_fops = {
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.owner = THIS_MODULE,
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.llseek = cpuid_seek,
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.read = cpuid_read,
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.open = cpuid_open,
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};
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static int cpuid_class_simple_device_add(int i)
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{
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int err = 0;
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struct class_device *class_err;
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class_err = class_simple_device_add(cpuid_class, MKDEV(CPUID_MAJOR, i), NULL, "cpu%d",i);
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if (IS_ERR(class_err))
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err = PTR_ERR(class_err);
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return err;
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}
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static int __devinit cpuid_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
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{
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unsigned int cpu = (unsigned long)hcpu;
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switch (action) {
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case CPU_ONLINE:
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cpuid_class_simple_device_add(cpu);
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break;
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case CPU_DEAD:
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class_simple_device_remove(MKDEV(CPUID_MAJOR, cpu));
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block cpuid_class_cpu_notifier =
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{
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.notifier_call = cpuid_class_cpu_callback,
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};
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static int __init cpuid_init(void)
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{
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int i, err = 0;
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i = 0;
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if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
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printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
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CPUID_MAJOR);
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err = -EBUSY;
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goto out;
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}
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cpuid_class = class_simple_create(THIS_MODULE, "cpuid");
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if (IS_ERR(cpuid_class)) {
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err = PTR_ERR(cpuid_class);
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goto out_chrdev;
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}
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for_each_online_cpu(i) {
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err = cpuid_class_simple_device_add(i);
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if (err != 0)
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goto out_class;
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}
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register_cpu_notifier(&cpuid_class_cpu_notifier);
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err = 0;
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goto out;
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out_class:
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i = 0;
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for_each_online_cpu(i) {
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class_simple_device_remove(MKDEV(CPUID_MAJOR, i));
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}
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class_simple_destroy(cpuid_class);
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out_chrdev:
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unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
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out:
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return err;
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}
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static void __exit cpuid_exit(void)
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{
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int cpu = 0;
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for_each_online_cpu(cpu)
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class_simple_device_remove(MKDEV(CPUID_MAJOR, cpu));
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class_simple_destroy(cpuid_class);
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unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
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unregister_cpu_notifier(&cpuid_class_cpu_notifier);
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}
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module_init(cpuid_init);
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module_exit(cpuid_exit);
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MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
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MODULE_DESCRIPTION("x86 generic CPUID driver");
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MODULE_LICENSE("GPL");
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