![Rafael J. Wysocki](/assets/img/avatar_default.png)
Since nonboot CPUs are now disabled after tasks and devices have been frozen and the CPU hotplug infrastructure is used for this purpose, we need special CPU hotplug notifications that will help the CPU-hotplug-aware subsystems distinguish normal CPU hotplug events from CPU hotplug events related to a system-wide suspend or resume operation in progress. This patch introduces such notifications and causes them to be used during suspend and resume transitions. It also changes all of the CPU-hotplug-aware subsystems to take these notifications into consideration (for now they are handled in the same way as the corresponding "normal" ones). [oleg@tv-sign.ru: cleanups] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
243 lines
5.2 KiB
C
243 lines
5.2 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/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/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 *cpuid_class;
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#ifdef CONFIG_SMP
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struct cpuid_command {
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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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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.reg = reg;
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cmd.data = data;
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smp_call_function_single(cpu, 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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u32 reg = *ppos;
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int cpu = iminor(file->f_path.dentry->d_inode);
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if (count % 16)
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return -EINVAL; /* Invalid chunk size */
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for (; 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_path.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 const 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_device_create(int i)
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{
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int err = 0;
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struct device *dev;
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dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, i), "cpu%d",i);
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if (IS_ERR(dev))
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err = PTR_ERR(dev);
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return err;
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}
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static int 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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case CPU_ONLINE_FROZEN:
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cpuid_device_create(cpu);
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break;
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case CPU_DEAD:
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case CPU_DEAD_FROZEN:
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device_destroy(cpuid_class, 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 __cpuinitdata 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_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_device_create(i);
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if (err != 0)
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goto out_class;
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}
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register_hotcpu_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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device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, i));
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}
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class_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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device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
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class_destroy(cpuid_class);
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unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
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unregister_hotcpu_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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