Release 4.11 arch/x86/kernel/cpu/mcheck/mce-inject.c

/*
 * 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/preempt.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;
}

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84.62%
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Huang Ying
11
14.10%
1
25.00%
Lucas De Marchi
1
1.28%
1
25.00%
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78
100.00%
4
100.00%



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;
}

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static void raise_exception(struct mce *m, struct pt_regs *pregs)
{
	struct pt_regs regs;
	unsigned long flags;

	if (!pregs) {
		memset(&regs, 0, sizeof(struct pt_regs));
		regs.ip = m->ip;
		regs.cs = m->cs;
		pregs = &regs;
	}
	/* in mcheck exeception handler, irq will be disabled */
	local_irq_save(flags);
	do_machine_check(pregs, 0);
	local_irq_restore(flags);
	m->finished = 0;
}

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static cpumask_var_t mce_inject_cpumask;
static DEFINE_MUTEX(mce_inject_mutex);



static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
{
	int cpu = smp_processor_id();
	struct mce *m = this_cpu_ptr(&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;
}

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71
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Don Zickus
7
8.54%
1
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Rusty Russell
2
2.44%
1
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Christoph Lameter
2
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static void mce_irq_ipi(void *info)
{
	int cpu = smp_processor_id();
	struct mce *m = this_cpu_ptr(&injectm);

	if (cpumask_test_cpu(cpu, mce_inject_cpumask) &&
			m->inject_flags & MCJ_EXCEPTION) {
		cpumask_clear_cpu(cpu, mce_inject_cpumask);
		raise_exception(m, NULL);
	}
}

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/* Inject mce on current CPU */


static int raise_local(void)
{
	struct mce *m = this_cpu_ptr(&injectm);
	int context = MCJ_CTX(m->inject_flags);
	int ret = 0;
	int cpu = m->extcpu;

	if (m->inject_flags & MCJ_EXCEPTION) {
		pr_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:
			pr_info("Invalid MCE context\n");
			ret = -EINVAL;
		}
		pr_info("MCE exception done on CPU %d\n", cpu);
	} else if (m->status) {
		pr_info("Starting machine check poll CPU %d\n", cpu);
		raise_poll(m);
		mce_notify_irq();
		pr_info("Machine check poll done on CPU %d\n", cpu);
	} else
		m->finished = 0;

	return ret;
}

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125
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3
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Andi Kleen
7
5.04%
1
16.67%
Chen Yucong
5
3.60%
1
16.67%
Christoph Lameter
2
1.44%
1
16.67%
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139
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6
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static void raise_mce(struct mce *m)
{
	int context = MCJ_CTX(m->inject_flags);

	inject_mce(m);

	if (context == MCJ_CTX_RANDOM)
		return;

	if (m->inject_flags & (MCJ_IRQ_BROADCAST | 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)) {
			if (m->inject_flags & MCJ_IRQ_BROADCAST) {
				/*
                                 * don't wait because mce_irq_ipi is necessary
                                 * to be sync with following raise_local
                                 */
				preempt_disable();
				smp_call_function_many(mce_inject_cpumask,
					mce_irq_ipi, NULL, 0);
				preempt_enable();
			} else if (m->inject_flags & MCJ_NMI_BROADCAST)
				apic->send_IPI_mask(mce_inject_cpumask,
						NMI_VECTOR);
		}
		start = jiffies;
		while (!cpumask_empty(mce_inject_cpumask)) {
			if (!time_before(jiffies, start + 2*HZ)) {
				pr_err("Timeout waiting for mce inject %lx\n",
					*cpumask_bits(mce_inject_cpumask));
				break;
			}
			cpu_relax();
		}
		raise_local();
		put_cpu();
		put_online_cpus();
	} else {
		preempt_disable();
		raise_local();
		preempt_enable();
	}
}

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58
24.58%
1
12.50%
Chen Gong
42
17.80%
1
12.50%
Rusty Russell
10
4.24%
1
12.50%
Thomas Gleixner
8
3.39%
1
12.50%
Mathias Krause
2
0.85%
1
12.50%
Chen Yucong
1
0.42%
1
12.50%
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/* 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);

	mutex_lock(&mce_inject_mutex);
	raise_mce(&m);
	mutex_unlock(&mce_inject_mutex);
	return usize;
}

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12
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1
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Huang Ying
3
2.07%
1
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Hidetoshi Seto
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static int inject_init(void)
{
	if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
		return -ENOMEM;
	pr_info("Machine check injector initialized\n");
	register_mce_write_callback(mce_write);
	register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0,
				"mce_notify");
	return 0;
}

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1
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Don Zickus
8
17.02%
1
16.67%
Tony Luck
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Huang Ying
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1
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Chen Yucong
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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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310
30.91%
2
10.53%
Chen Gong
101
10.07%
1
5.26%
Rusty Russell
28
2.79%
1
5.26%
Thomas Gleixner
26
2.59%
2
10.53%
Don Zickus
18
1.79%
2
10.53%
Chen Yucong
7
0.70%
1
5.26%
Christoph Lameter
6
0.60%
1
5.26%
Hidetoshi Seto
5
0.50%
1
5.26%
Tejun Heo
3
0.30%
1
5.26%
Tony Luck
3
0.30%
1
5.26%
Mathias Krause
2
0.20%
1
5.26%
Lucas De Marchi
1
0.10%
1
5.26%
H. Peter Anvin
1
0.10%
1
5.26%
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Directory: arch/x86/kernel/cpu/mcheck

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