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/preempt.h>
  21 #include <linux/smp.h>
  22 #include <linux/notifier.h>
  23 #include <linux/kdebug.h>
  24 #include <linux/cpu.h>
  25 #include <linux/sched.h>
  26 #include <linux/gfp.h>
  27 #include <asm/mce.h>
  28 #include <asm/apic.h>
  29 #include <asm/nmi.h>
  30
  31 /* Update fake mce registers on current CPU. */
  32 static void inject_mce(struct mce *m)
  33 {
  34         struct mce *i = &per_cpu(injectm, m->extcpu);
  35
  36         /* Make sure no one reads partially written injectm */
  37         i->finished = 0;
  38         mb();
  39         m->finished = 0;
  40         /* First set the fields after finished */
  41         i->extcpu = m->extcpu;
  42         mb();
  43         /* Now write record in order, finished last (except above) */
  44         memcpy(i, m, sizeof(struct mce));
  45         /* Finally activate it */
  46         mb();
  47         i->finished = 1;
  48 }
  49
  50 static void raise_poll(struct mce *m)
  51 {
  52         unsigned long flags;
  53         mce_banks_t b;
  54
  55         memset(&b, 0xff, sizeof(mce_banks_t));
  56         local_irq_save(flags);
  57         machine_check_poll(0, &b);
  58         local_irq_restore(flags);
  59         m->finished = 0;
  60 }
  61
  62 static void raise_exception(struct mce *m, struct pt_regs *pregs)
  63 {
  64         struct pt_regs regs;
  65         unsigned long flags;
  66
  67         if (!pregs) {
  68                 memset(&regs, 0, sizeof(struct pt_regs));
  69                 regs.ip = m->ip;
  70                 regs.cs = m->cs;
  71                 pregs = &regs;
  72         }
  73         /* in mcheck exeception handler, irq will be disabled */
  74         local_irq_save(flags);
  75         do_machine_check(pregs, 0);
  76         local_irq_restore(flags);
  77         m->finished = 0;
  78 }
  79
  80 static cpumask_var_t mce_inject_cpumask;
  81
  82 static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
  83 {
  84         int cpu = smp_processor_id();
  85         struct mce *m = &__get_cpu_var(injectm);
  86         if (!cpumask_test_cpu(cpu, mce_inject_cpumask))
  87                 return NMI_DONE;
  88         cpumask_clear_cpu(cpu, mce_inject_cpumask);
  89         if (m->inject_flags & MCJ_EXCEPTION)
  90                 raise_exception(m, regs);
  91         else if (m->status)
  92                 raise_poll(m);
  93         return NMI_HANDLED;
  94 }
  95
  96 static void mce_irq_ipi(void *info)
  97 {
  98         int cpu = smp_processor_id();
  99         struct mce *m = &__get_cpu_var(injectm);
 100
 101         if (cpumask_test_cpu(cpu, mce_inject_cpumask) &&
 102                         m->inject_flags & MCJ_EXCEPTION) {
 103                 cpumask_clear_cpu(cpu, mce_inject_cpumask);
 104                 raise_exception(m, NULL);
 105         }
 106 }
 107
 108 /* Inject mce on current CPU */
 109 static int raise_local(void)
 110 {
 111         struct mce *m = &__get_cpu_var(injectm);
 112         int context = MCJ_CTX(m->inject_flags);
 113         int ret = 0;
 114         int cpu = m->extcpu;
 115
 116         if (m->inject_flags & MCJ_EXCEPTION) {
 117                 printk(KERN_INFO "Triggering MCE exception on CPU %d\n", cpu);
 118                 switch (context) {
 119                 case MCJ_CTX_IRQ:
 120                         /*
 121                          * Could do more to fake interrupts like
 122                          * calling irq_enter, but the necessary
 123                          * machinery isn't exported currently.
 124                          */
 125                         /*FALL THROUGH*/
 126                 case MCJ_CTX_PROCESS:
 127                         raise_exception(m, NULL);
 128                         break;
 129                 default:
 130                         printk(KERN_INFO "Invalid MCE context\n");
 131                         ret = -EINVAL;
 132                 }
 133                 printk(KERN_INFO "MCE exception done on CPU %d\n", cpu);
 134         } else if (m->status) {
 135                 printk(KERN_INFO "Starting machine check poll CPU %d\n", cpu);
 136                 raise_poll(m);
 137                 mce_notify_irq();
 138                 printk(KERN_INFO "Machine check poll done on CPU %d\n", cpu);
 139         } else
 140                 m->finished = 0;
 141
 142         return ret;
 143 }
 144
 145 static void raise_mce(struct mce *m)
 146 {
 147         int context = MCJ_CTX(m->inject_flags);
 148
 149         inject_mce(m);
 150
 151         if (context == MCJ_CTX_RANDOM)
 152                 return;
 153
 154 #ifdef CONFIG_X86_LOCAL_APIC
 155         if (m->inject_flags & (MCJ_IRQ_BRAODCAST | MCJ_NMI_BROADCAST)) {
 156                 unsigned long start;
 157                 int cpu;
 158
 159                 get_online_cpus();
 160                 cpumask_copy(mce_inject_cpumask, cpu_online_mask);
 161                 cpumask_clear_cpu(get_cpu(), mce_inject_cpumask);
 162                 for_each_online_cpu(cpu) {
 163                         struct mce *mcpu = &per_cpu(injectm, cpu);
 164                         if (!mcpu->finished ||
 165                             MCJ_CTX(mcpu->inject_flags) != MCJ_CTX_RANDOM)
 166                                 cpumask_clear_cpu(cpu, mce_inject_cpumask);
 167                 }
 168                 if (!cpumask_empty(mce_inject_cpumask)) {
 169                         if (m->inject_flags & MCJ_IRQ_BRAODCAST) {
 170                                 /*
 171                                  * don't wait because mce_irq_ipi is necessary
 172                                  * to be sync with following raise_local
 173                                  */
 174                                 preempt_disable();
 175                                 smp_call_function_many(mce_inject_cpumask,
 176                                         mce_irq_ipi, NULL, 0);
 177                                 preempt_enable();
 178                         } else if (m->inject_flags & MCJ_NMI_BROADCAST)
 179                                 apic->send_IPI_mask(mce_inject_cpumask,
 180                                                 NMI_VECTOR);
 181                 }
 182                 start = jiffies;
 183                 while (!cpumask_empty(mce_inject_cpumask)) {
 184                         if (!time_before(jiffies, start + 2*HZ)) {
 185                                 printk(KERN_ERR
 186                                 "Timeout waiting for mce inject %lx\n",
 187                                         *cpumask_bits(mce_inject_cpumask));
 188                                 break;
 189                         }
 190                         cpu_relax();
 191                 }
 192                 raise_local();
 193                 put_cpu();
 194                 put_online_cpus();
 195         } else
 196 #endif
 197                 raise_local();
 198 }
 199
 200 /* Error injection interface */
 201 static ssize_t mce_write(struct file *filp, const char __user *ubuf,
 202                          size_t usize, loff_t *off)
 203 {
 204         struct mce m;
 205
 206         if (!capable(CAP_SYS_ADMIN))
 207                 return -EPERM;
 208         /*
 209          * There are some cases where real MSR reads could slip
 210          * through.
 211          */
 212         if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
 213                 return -EIO;
 214
 215         if ((unsigned long)usize > sizeof(struct mce))
 216                 usize = sizeof(struct mce);
 217         if (copy_from_user(&m, ubuf, usize))
 218                 return -EFAULT;
 219
 220         if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
 221                 return -EINVAL;
 222
 223         /*
 224          * Need to give user space some time to set everything up,
 225          * so do it a jiffie or two later everywhere.
 226          */
 227         schedule_timeout(2);
 228         raise_mce(&m);
 229         return usize;
 230 }
 231
 232 static int inject_init(void)
 233 {
 234         if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
 235                 return -ENOMEM;
 236         printk(KERN_INFO "Machine check injector initialized\n");
 237         register_mce_write_callback(mce_write);
 238         register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0,
 239                                 "mce_notify");
 240         return 0;
 241 }
 242
 243 module_init(inject_init);
 244 /*
 245  * Cannot tolerate unloading currently because we cannot
 246  * guarantee all openers of mce_chrdev will get a reference to us.
 247  */
 248 MODULE_LICENSE("GPL");