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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 <linux/notifier.h>
#include <linux/kdebug.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/gfp.h>
#include <asm/mce.h>
#include <asm/apic.h>
#include <asm/nmi.h>
/* Update fake mce registers on current CPU. */
static void inject_mce(struct mce *m)
{
struct mce *i = &per_cpu(injectm, m->extcpu);
/* Make sure no one reads partially written injectm */
i->finished = 0;
mb();
m->finished = 0;
/* First set the fields after finished */
i->extcpu = m->extcpu;
mb();
/* Now write record in order, finished last (except above) */
memcpy(i, m, sizeof(struct mce));
/* Finally activate it */
mb();
i->finished = 1;
}
static void raise_poll(struct mce *m)
{
unsigned long flags;
mce_banks_t b;
memset(&b, 0xff, sizeof(mce_banks_t));
local_irq_save(flags);
machine_check_poll(0, &b);
local_irq_restore(flags);
m->finished = 0;
}
static void raise_exception(struct mce *m, struct pt_regs *pregs)
{
struct pt_regs regs;
unsigned long flags;
if (!pregs) {
memset(®s, 0, sizeof(struct pt_regs));
regs.ip = m->ip;
regs.cs = m->cs;
pregs = ®s;
}
/* in mcheck exeception handler, irq will be disabled */
local_irq_save(flags);
do_machine_check(pregs, 0);
local_irq_restore(flags);
m->finished = 0;
}
static cpumask_var_t mce_inject_cpumask;
static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
{
int cpu = smp_processor_id();
struct mce *m = &__get_cpu_var(injectm);
if (!cpumask_test_cpu(cpu, mce_inject_cpumask))
return NMI_DONE;
cpumask_clear_cpu(cpu, mce_inject_cpumask);
if (m->inject_flags & MCJ_EXCEPTION)
raise_exception(m, regs);
else if (m->status)
raise_poll(m);
return NMI_HANDLED;
}
/* Inject mce on current CPU */
static int raise_local(void)
{
struct mce *m = &__get_cpu_var(injectm);
int context = MCJ_CTX(m->inject_flags);
int ret = 0;
int cpu = m->extcpu;
if (m->inject_flags & MCJ_EXCEPTION) {
printk(KERN_INFO "Triggering MCE exception on CPU %d\n", cpu);
switch (context) {
case MCJ_CTX_IRQ:
/*
* Could do more to fake interrupts like
* calling irq_enter, but the necessary
* machinery isn't exported currently.
*/
/*FALL THROUGH*/
case MCJ_CTX_PROCESS:
raise_exception(m, NULL);
break;
default:
printk(KERN_INFO "Invalid MCE context\n");
ret = -EINVAL;
}
printk(KERN_INFO "MCE exception done on CPU %d\n", cpu);
} else if (m->status) {
printk(KERN_INFO "Starting machine check poll CPU %d\n", cpu);
raise_poll(m);
mce_notify_irq();
printk(KERN_INFO "Machine check poll done on CPU %d\n", cpu);
} else
m->finished = 0;
return ret;
}
static void raise_mce(struct mce *m)
{
int context = MCJ_CTX(m->inject_flags);
inject_mce(m);
if (context == MCJ_CTX_RANDOM)
return;
#ifdef CONFIG_X86_LOCAL_APIC
if (m->inject_flags & MCJ_NMI_BROADCAST) {
unsigned long start;
int cpu;
get_online_cpus();
cpumask_copy(mce_inject_cpumask, cpu_online_mask);
cpumask_clear_cpu(get_cpu(), mce_inject_cpumask);
for_each_online_cpu(cpu) {
struct mce *mcpu = &per_cpu(injectm, cpu);
if (!mcpu->finished ||
MCJ_CTX(mcpu->inject_flags) != MCJ_CTX_RANDOM)
cpumask_clear_cpu(cpu, mce_inject_cpumask);
}
if (!cpumask_empty(mce_inject_cpumask))
apic->send_IPI_mask(mce_inject_cpumask, NMI_VECTOR);
start = jiffies;
while (!cpumask_empty(mce_inject_cpumask)) {
if (!time_before(jiffies, start + 2*HZ)) {
printk(KERN_ERR
"Timeout waiting for mce inject NMI %lx\n",
*cpumask_bits(mce_inject_cpumask));
break;
}
cpu_relax();
}
raise_local();
put_cpu();
put_online_cpus();
} else
#endif
raise_local();
}
/* Error injection interface */
static ssize_t mce_write(struct file *filp, const char __user *ubuf,
size_t usize, loff_t *off)
{
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.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
return -EINVAL;
/*
* Need to give user space some time to set everything up,
* so do it a jiffie or two later everywhere.
*/
schedule_timeout(2);
raise_mce(&m);
return usize;
}
static int inject_init(void)
{
if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
return -ENOMEM;
printk(KERN_INFO "Machine check injector initialized\n");
mce_chrdev_ops.write = mce_write;
register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0,
"mce_notify");
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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