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

   1 /*
   2  * Machine check injection support.
   3  * Copyright 2008 Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; version 2
   8  * of the License.
   9  *
  10  * Authors:
  11  * Andi Kleen
  12  * Ying Huang
  13  */
  14 #include <linux/uaccess.h>
  15 #include <linux/module.h>
  16 #include <linux/timer.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/fs.h>
  20 #include <linux/smp.h>
  21 #include <linux/notifier.h>
  22 #include <linux/kdebug.h>
  23 #include <linux/cpu.h>
  24 #include <linux/sched.h>
  25 #include <linux/gfp.h>
  26 #include <asm/mce.h>
  27 #include <asm/apic.h>
  28 #include <asm/nmi.h>
  29
  30 /* Update fake mce registers on current CPU. */
  31 static void inject_mce(struct mce *m)
  32 {
  33         struct mce *i = &per_cpu(injectm, m->extcpu);
  34
  35         /* Make sure no one reads partially written injectm */
  36         i->finished = 0;
  37         mb();
  38         m->finished = 0;
  39         /* First set the fields after finished */
  40         i->extcpu = m->extcpu;
  41         mb();
  42         /* Now write record in order, finished last (except above) */
  43         memcpy(i, m, sizeof(struct mce));
  44         /* Finally activate it */
  45         mb();
  46         i->finished = 1;
  47 }
  48
  49 static void raise_poll(struct mce *m)
  50 {
  51         unsigned long flags;
  52         mce_banks_t b;
  53
  54         memset(&b, 0xff, sizeof(mce_banks_t));
  55         local_irq_save(flags);
  56         machine_check_poll(0, &b);
  57         local_irq_restore(flags);
  58         m->finished = 0;
  59 }
  60
  61 static void raise_exception(struct mce *m, struct pt_regs *pregs)
  62 {
  63         struct pt_regs regs;
  64         unsigned long flags;
  65
  66         if (!pregs) {
  67                 memset(&regs, 0, sizeof(struct pt_regs));
  68                 regs.ip = m->ip;
  69                 regs.cs = m->cs;
  70                 pregs = &regs;
  71         }
  72         /* in mcheck exeception handler, irq will be disabled */
  73         local_irq_save(flags);
  74         do_machine_check(pregs, 0);
  75         local_irq_restore(flags);
  76         m->finished = 0;
  77 }
  78
  79 static cpumask_var_t mce_inject_cpumask;
  80
  81 static int mce_raise_notify(struct notifier_block *self,
  82                             unsigned long val, void *data)
  83 {
  84         struct die_args *args = (struct die_args *)data;
  85         int cpu = smp_processor_id();
  86         struct mce *m = &__get_cpu_var(injectm);
  87         if (val != DIE_NMI || !cpumask_test_cpu(cpu, mce_inject_cpumask))
  88                 return NOTIFY_DONE;
  89         cpumask_clear_cpu(cpu, mce_inject_cpumask);
  90         if (m->inject_flags & MCJ_EXCEPTION)
  91                 raise_exception(m, args->regs);
  92         else if (m->status)
  93                 raise_poll(m);
  94         return NOTIFY_STOP;
  95 }
  96
  97 static struct notifier_block mce_raise_nb = {
  98         .notifier_call = mce_raise_notify,
  99         .priority = NMI_LOCAL_NORMAL_PRIOR,
 100 };
 101
 102 /* Inject mce on current CPU */
 103 static int raise_local(void)
 104 {
 105         struct mce *m = &__get_cpu_var(injectm);
 106         int context = MCJ_CTX(m->inject_flags);
 107         int ret = 0;
 108         int cpu = m->extcpu;
 109
 110         if (m->inject_flags & MCJ_EXCEPTION) {
 111                 printk(KERN_INFO "Triggering MCE exception on CPU %d\n", cpu);
 112                 switch (context) {
 113                 case MCJ_CTX_IRQ:
 114                         /*
 115                          * Could do more to fake interrupts like
 116                          * calling irq_enter, but the necessary
 117                          * machinery isn't exported currently.
 118                          */
 119                         /*FALL THROUGH*/
 120                 case MCJ_CTX_PROCESS:
 121                         raise_exception(m, NULL);
 122                         break;
 123                 default:
 124                         printk(KERN_INFO "Invalid MCE context\n");
 125                         ret = -EINVAL;
 126                 }
 127                 printk(KERN_INFO "MCE exception done on CPU %d\n", cpu);
 128         } else if (m->status) {
 129                 printk(KERN_INFO "Starting machine check poll CPU %d\n", cpu);
 130                 raise_poll(m);
 131                 mce_notify_irq();
 132                 printk(KERN_INFO "Machine check poll done on CPU %d\n", cpu);
 133         } else
 134                 m->finished = 0;
 135
 136         return ret;
 137 }
 138
 139 static void raise_mce(struct mce *m)
 140 {
 141         int context = MCJ_CTX(m->inject_flags);
 142
 143         inject_mce(m);
 144
 145         if (context == MCJ_CTX_RANDOM)
 146                 return;
 147
 148 #ifdef CONFIG_X86_LOCAL_APIC
 149         if (m->inject_flags & MCJ_NMI_BROADCAST) {
 150                 unsigned long start;
 151                 int cpu;
 152                 get_online_cpus();
 153                 cpumask_copy(mce_inject_cpumask, cpu_online_mask);
 154                 cpumask_clear_cpu(get_cpu(), mce_inject_cpumask);
 155                 for_each_online_cpu(cpu) {
 156                         struct mce *mcpu = &per_cpu(injectm, cpu);
 157                         if (!mcpu->finished ||
 158                             MCJ_CTX(mcpu->inject_flags) != MCJ_CTX_RANDOM)
 159                                 cpumask_clear_cpu(cpu, mce_inject_cpumask);
 160                 }
 161                 if (!cpumask_empty(mce_inject_cpumask))
 162                         apic->send_IPI_mask(mce_inject_cpumask, NMI_VECTOR);
 163                 start = jiffies;
 164                 while (!cpumask_empty(mce_inject_cpumask)) {
 165                         if (!time_before(jiffies, start + 2*HZ)) {
 166                                 printk(KERN_ERR
 167                                 "Timeout waiting for mce inject NMI %lx\n",
 168                                         *cpumask_bits(mce_inject_cpumask));
 169                                 break;
 170                         }
 171                         cpu_relax();
 172                 }
 173                 raise_local();
 174                 put_cpu();
 175                 put_online_cpus();
 176         } else
 177 #endif
 178                 raise_local();
 179 }
 180
 181 /* Error injection interface */
 182 static ssize_t mce_write(struct file *filp, const char __user *ubuf,
 183                          size_t usize, loff_t *off)
 184 {
 185         struct mce m;
 186
 187         if (!capable(CAP_SYS_ADMIN))
 188                 return -EPERM;
 189         /*
 190          * There are some cases where real MSR reads could slip
 191          * through.
 192          */
 193         if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
 194                 return -EIO;
 195
 196         if ((unsigned long)usize > sizeof(struct mce))
 197                 usize = sizeof(struct mce);
 198         if (copy_from_user(&m, ubuf, usize))
 199                 return -EFAULT;
 200
 201         if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
 202                 return -EINVAL;
 203
 204         /*
 205          * Need to give user space some time to set everything up,
 206          * so do it a jiffie or two later everywhere.
 207          */
 208         schedule_timeout(2);
 209         raise_mce(&m);
 210         return usize;
 211 }
 212
 213 static int inject_init(void)
 214 {
 215         if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
 216                 return -ENOMEM;
 217         printk(KERN_INFO "Machine check injector initialized\n");
 218         mce_chrdev_ops.write = mce_write;
 219         register_die_notifier(&mce_raise_nb);
 220         return 0;
 221 }
 222
 223 module_init(inject_init);
 224 /*
 225  * Cannot tolerate unloading currently because we cannot
 226  * guarantee all openers of mce_chrdev will get a reference to us.
 227  */
 228 MODULE_LICENSE("GPL");