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/*
* Machine check injection support.
* Copyright 2008 Intel Corporation.
*
* 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; version 2
* of the License.
*
* Authors:
* Andi Kleen
* Ying Huang
*/
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <asm/mce.h>
/* Update fake mce registers on current CPU. */
static void inject_mce(struct mce *m)
{
struct mce *i = &per_cpu(injectm, m->cpu);
/* Make sure noone reads partially written injectm */
i->finished = 0;
mb();
m->finished = 0;
/* First set the fields after finished */
i->cpu = m->cpu;
mb();
/* Now write record in order, finished last (except above) */
memcpy(i, m, sizeof(struct mce));
/* Finally activate it */
mb();
i->finished = 1;
}
struct delayed_mce {
struct timer_list timer;
struct mce m;
};
/* Inject mce on current CPU */
static void raise_mce(unsigned long data)
{
struct delayed_mce *dm = (struct delayed_mce *)data;
struct mce *m = &dm->m;
int cpu = m->cpu;
inject_mce(m);
if (m->status & MCI_STATUS_UC) {
struct pt_regs regs;
memset(®s, 0, sizeof(struct pt_regs));
regs.ip = m->ip;
regs.cs = m->cs;
printk(KERN_INFO "Triggering MCE exception on CPU %d\n", cpu);
do_machine_check(®s, 0);
printk(KERN_INFO "MCE exception done on CPU %d\n", cpu);
} else {
mce_banks_t b;
memset(&b, 0xff, sizeof(mce_banks_t));
printk(KERN_INFO "Starting machine check poll CPU %d\n", cpu);
machine_check_poll(0, &b);
mce_notify_user();
printk(KERN_INFO "Finished machine check poll on CPU %d\n",
cpu);
}
kfree(dm);
}
/* Error injection interface */
static ssize_t mce_write(struct file *filp, const char __user *ubuf,
size_t usize, loff_t *off)
{
struct delayed_mce *dm;
struct mce m;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/*
* There are some cases where real MSR reads could slip
* through.
*/
if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
return -EIO;
if ((unsigned long)usize > sizeof(struct mce))
usize = sizeof(struct mce);
if (copy_from_user(&m, ubuf, usize))
return -EFAULT;
if (m.cpu >= num_possible_cpus() || !cpu_online(m.cpu))
return -EINVAL;
dm = kmalloc(sizeof(struct delayed_mce), GFP_KERNEL);
if (!dm)
return -ENOMEM;
/*
* Need to give user space some time to set everything up,
* so do it a jiffie or two later everywhere.
* Should we use a hrtimer here for better synchronization?
*/
memcpy(&dm->m, &m, sizeof(struct mce));
setup_timer(&dm->timer, raise_mce, (unsigned long)dm);
dm->timer.expires = jiffies + 2;
add_timer_on(&dm->timer, m.cpu);
return usize;
}
static int inject_init(void)
{
printk(KERN_INFO "Machine check injector initialized\n");
mce_chrdev_ops.write = mce_write;
return 0;
}
module_init(inject_init);
/*
* Cannot tolerate unloading currently because we cannot
* guarantee all openers of mce_chrdev will get a reference to us.
*/
MODULE_LICENSE("GPL");
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