| /* |
| * 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; |
| } |
| |
| 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 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; |
| } |
| |
| 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); |
| } |
| } |
| |
| /* 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) { |
| 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_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)) { |
| printk(KERN_ERR |
| "Timeout waiting for mce inject %lx\n", |
| *cpumask_bits(mce_inject_cpumask)); |
| break; |
| } |
| cpu_relax(); |
| } |
| raise_local(); |
| put_cpu(); |
| put_online_cpus(); |
| } else |
| #endif |
| { |
| preempt_disable(); |
| raise_local(); |
| preempt_enable(); |
| } |
| } |
| |
| /* 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; |
| } |
| |
| static int inject_init(void) |
| { |
| if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL)) |
| return -ENOMEM; |
| printk(KERN_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; |
| } |
| |
| 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"); |