2 * Machine check injection support.
3 * Copyright 2008 Intel Corporation.
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
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>
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>
31 /* Update fake mce registers on current CPU. */
32 static void inject_mce(struct mce *m)
34 struct mce *i = &per_cpu(injectm, m->extcpu);
36 /* Make sure no one reads partially written injectm */
40 /* First set the fields after finished */
41 i->extcpu = m->extcpu;
43 /* Now write record in order, finished last (except above) */
44 memcpy(i, m, sizeof(struct mce));
45 /* Finally activate it */
50 static void raise_poll(struct mce *m)
55 memset(&b, 0xff, sizeof(mce_banks_t));
56 local_irq_save(flags);
57 machine_check_poll(0, &b);
58 local_irq_restore(flags);
62 static void raise_exception(struct mce *m, struct pt_regs *pregs)
68 memset(®s, 0, sizeof(struct pt_regs));
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);
80 static cpumask_var_t mce_inject_cpumask;
81 static DEFINE_MUTEX(mce_inject_mutex);
83 static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
85 int cpu = smp_processor_id();
86 struct mce *m = this_cpu_ptr(&injectm);
87 if (!cpumask_test_cpu(cpu, mce_inject_cpumask))
89 cpumask_clear_cpu(cpu, mce_inject_cpumask);
90 if (m->inject_flags & MCJ_EXCEPTION)
91 raise_exception(m, regs);
97 static void mce_irq_ipi(void *info)
99 int cpu = smp_processor_id();
100 struct mce *m = this_cpu_ptr(&injectm);
102 if (cpumask_test_cpu(cpu, mce_inject_cpumask) &&
103 m->inject_flags & MCJ_EXCEPTION) {
104 cpumask_clear_cpu(cpu, mce_inject_cpumask);
105 raise_exception(m, NULL);
109 /* Inject mce on current CPU */
110 static int raise_local(void)
112 struct mce *m = this_cpu_ptr(&injectm);
113 int context = MCJ_CTX(m->inject_flags);
117 if (m->inject_flags & MCJ_EXCEPTION) {
118 pr_info("Triggering MCE exception on CPU %d\n", cpu);
122 * Could do more to fake interrupts like
123 * calling irq_enter, but the necessary
124 * machinery isn't exported currently.
127 case MCJ_CTX_PROCESS:
128 raise_exception(m, NULL);
131 pr_info("Invalid MCE context\n");
134 pr_info("MCE exception done on CPU %d\n", cpu);
135 } else if (m->status) {
136 pr_info("Starting machine check poll CPU %d\n", cpu);
139 pr_info("Machine check poll done on CPU %d\n", cpu);
146 static void raise_mce(struct mce *m)
148 int context = MCJ_CTX(m->inject_flags);
152 if (context == MCJ_CTX_RANDOM)
155 if (m->inject_flags & (MCJ_IRQ_BROADCAST | MCJ_NMI_BROADCAST)) {
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);
168 if (!cpumask_empty(mce_inject_cpumask)) {
169 if (m->inject_flags & MCJ_IRQ_BROADCAST) {
171 * don't wait because mce_irq_ipi is necessary
172 * to be sync with following raise_local
175 smp_call_function_many(mce_inject_cpumask,
176 mce_irq_ipi, NULL, 0);
178 } else if (m->inject_flags & MCJ_NMI_BROADCAST)
179 apic->send_IPI_mask(mce_inject_cpumask,
183 while (!cpumask_empty(mce_inject_cpumask)) {
184 if (!time_before(jiffies, start + 2*HZ)) {
185 pr_err("Timeout waiting for mce inject %lx\n",
186 *cpumask_bits(mce_inject_cpumask));
201 /* Error injection interface */
202 static ssize_t mce_write(struct file *filp, const char __user *ubuf,
203 size_t usize, loff_t *off)
207 if (!capable(CAP_SYS_ADMIN))
210 * There are some cases where real MSR reads could slip
213 if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
216 if ((unsigned long)usize > sizeof(struct mce))
217 usize = sizeof(struct mce);
218 if (copy_from_user(&m, ubuf, usize))
221 if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
225 * Need to give user space some time to set everything up,
226 * so do it a jiffie or two later everywhere.
230 mutex_lock(&mce_inject_mutex);
232 mutex_unlock(&mce_inject_mutex);
236 static int inject_init(void)
238 if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
240 pr_info("Machine check injector initialized\n");
241 register_mce_write_callback(mce_write);
242 register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0,
247 module_init(inject_init);
249 * Cannot tolerate unloading currently because we cannot
250 * guarantee all openers of mce_chrdev will get a reference to us.
252 MODULE_LICENSE("GPL");