249 lines
5.9 KiB
C
249 lines
5.9 KiB
C
/*
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* Machine check injection support.
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* Copyright 2008 Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*
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* Authors:
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* Andi Kleen
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* Ying Huang
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*/
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/timer.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/fs.h>
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#include <linux/preempt.h>
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#include <linux/smp.h>
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#include <linux/notifier.h>
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#include <linux/kdebug.h>
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#include <linux/cpu.h>
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#include <linux/sched.h>
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#include <linux/gfp.h>
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#include <asm/mce.h>
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#include <asm/apic.h>
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#include <asm/nmi.h>
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/* Update fake mce registers on current CPU. */
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static void inject_mce(struct mce *m)
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{
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struct mce *i = &per_cpu(injectm, m->extcpu);
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/* Make sure no one reads partially written injectm */
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i->finished = 0;
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mb();
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m->finished = 0;
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/* First set the fields after finished */
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i->extcpu = m->extcpu;
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mb();
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/* Now write record in order, finished last (except above) */
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memcpy(i, m, sizeof(struct mce));
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/* Finally activate it */
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mb();
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i->finished = 1;
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}
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static void raise_poll(struct mce *m)
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{
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unsigned long flags;
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mce_banks_t b;
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memset(&b, 0xff, sizeof(mce_banks_t));
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local_irq_save(flags);
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machine_check_poll(0, &b);
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local_irq_restore(flags);
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m->finished = 0;
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}
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static void raise_exception(struct mce *m, struct pt_regs *pregs)
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{
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struct pt_regs regs;
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unsigned long flags;
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if (!pregs) {
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memset(®s, 0, sizeof(struct pt_regs));
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regs.ip = m->ip;
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regs.cs = m->cs;
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pregs = ®s;
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}
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/* in mcheck exeception handler, irq will be disabled */
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local_irq_save(flags);
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do_machine_check(pregs, 0);
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local_irq_restore(flags);
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m->finished = 0;
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}
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static cpumask_var_t mce_inject_cpumask;
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static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
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{
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int cpu = smp_processor_id();
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struct mce *m = &__get_cpu_var(injectm);
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if (!cpumask_test_cpu(cpu, mce_inject_cpumask))
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return NMI_DONE;
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cpumask_clear_cpu(cpu, mce_inject_cpumask);
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if (m->inject_flags & MCJ_EXCEPTION)
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raise_exception(m, regs);
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else if (m->status)
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raise_poll(m);
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return NMI_HANDLED;
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}
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static void mce_irq_ipi(void *info)
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{
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int cpu = smp_processor_id();
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struct mce *m = &__get_cpu_var(injectm);
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if (cpumask_test_cpu(cpu, mce_inject_cpumask) &&
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m->inject_flags & MCJ_EXCEPTION) {
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cpumask_clear_cpu(cpu, mce_inject_cpumask);
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raise_exception(m, NULL);
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}
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}
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/* Inject mce on current CPU */
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static int raise_local(void)
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{
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struct mce *m = &__get_cpu_var(injectm);
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int context = MCJ_CTX(m->inject_flags);
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int ret = 0;
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int cpu = m->extcpu;
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if (m->inject_flags & MCJ_EXCEPTION) {
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printk(KERN_INFO "Triggering MCE exception on CPU %d\n", cpu);
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switch (context) {
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case MCJ_CTX_IRQ:
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/*
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* Could do more to fake interrupts like
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* calling irq_enter, but the necessary
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* machinery isn't exported currently.
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*/
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/*FALL THROUGH*/
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case MCJ_CTX_PROCESS:
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raise_exception(m, NULL);
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break;
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default:
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printk(KERN_INFO "Invalid MCE context\n");
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ret = -EINVAL;
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}
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printk(KERN_INFO "MCE exception done on CPU %d\n", cpu);
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} else if (m->status) {
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printk(KERN_INFO "Starting machine check poll CPU %d\n", cpu);
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raise_poll(m);
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mce_notify_irq();
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printk(KERN_INFO "Machine check poll done on CPU %d\n", cpu);
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} else
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m->finished = 0;
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return ret;
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}
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static void raise_mce(struct mce *m)
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{
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int context = MCJ_CTX(m->inject_flags);
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inject_mce(m);
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if (context == MCJ_CTX_RANDOM)
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return;
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#ifdef CONFIG_X86_LOCAL_APIC
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if (m->inject_flags & (MCJ_IRQ_BRAODCAST | MCJ_NMI_BROADCAST)) {
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unsigned long start;
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int cpu;
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get_online_cpus();
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cpumask_copy(mce_inject_cpumask, cpu_online_mask);
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cpumask_clear_cpu(get_cpu(), mce_inject_cpumask);
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for_each_online_cpu(cpu) {
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struct mce *mcpu = &per_cpu(injectm, cpu);
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if (!mcpu->finished ||
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MCJ_CTX(mcpu->inject_flags) != MCJ_CTX_RANDOM)
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cpumask_clear_cpu(cpu, mce_inject_cpumask);
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}
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if (!cpumask_empty(mce_inject_cpumask)) {
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if (m->inject_flags & MCJ_IRQ_BRAODCAST) {
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/*
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* don't wait because mce_irq_ipi is necessary
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* to be sync with following raise_local
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*/
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preempt_disable();
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smp_call_function_many(mce_inject_cpumask,
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mce_irq_ipi, NULL, 0);
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preempt_enable();
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} else if (m->inject_flags & MCJ_NMI_BROADCAST)
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apic->send_IPI_mask(mce_inject_cpumask,
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NMI_VECTOR);
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}
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start = jiffies;
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while (!cpumask_empty(mce_inject_cpumask)) {
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if (!time_before(jiffies, start + 2*HZ)) {
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printk(KERN_ERR
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"Timeout waiting for mce inject %lx\n",
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*cpumask_bits(mce_inject_cpumask));
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break;
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}
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cpu_relax();
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}
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raise_local();
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put_cpu();
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put_online_cpus();
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} else
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#endif
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raise_local();
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}
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/* Error injection interface */
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static ssize_t mce_write(struct file *filp, const char __user *ubuf,
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size_t usize, loff_t *off)
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{
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struct mce m;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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/*
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* There are some cases where real MSR reads could slip
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* through.
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*/
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if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
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return -EIO;
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if ((unsigned long)usize > sizeof(struct mce))
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usize = sizeof(struct mce);
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if (copy_from_user(&m, ubuf, usize))
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return -EFAULT;
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if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
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return -EINVAL;
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/*
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* Need to give user space some time to set everything up,
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* so do it a jiffie or two later everywhere.
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*/
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schedule_timeout(2);
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raise_mce(&m);
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return usize;
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}
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static int inject_init(void)
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{
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if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
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return -ENOMEM;
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printk(KERN_INFO "Machine check injector initialized\n");
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register_mce_write_callback(mce_write);
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register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0,
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"mce_notify");
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return 0;
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}
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module_init(inject_init);
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/*
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* Cannot tolerate unloading currently because we cannot
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* guarantee all openers of mce_chrdev will get a reference to us.
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*/
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MODULE_LICENSE("GPL");
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