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 <asm/mce.h>
22
23 /* Update fake mce registers on current CPU. */
24 static void inject_mce(struct mce *m)
25 {
26 struct mce *i = &per_cpu(injectm, m->extcpu);
27
28 /* Make sure noone reads partially written injectm */
29 i->finished = 0;
30 mb();
31 m->finished = 0;
32 /* First set the fields after finished */
33 i->extcpu = m->extcpu;
34 mb();
35 /* Now write record in order, finished last (except above) */
36 memcpy(i, m, sizeof(struct mce));
37 /* Finally activate it */
38 mb();
39 i->finished = 1;
40 }
41
42 struct delayed_mce {
43 struct timer_list timer;
44 struct mce m;
45 };
46
47 /* Inject mce on current CPU */
48 static void raise_mce(unsigned long data)
49 {
50 struct delayed_mce *dm = (struct delayed_mce *)data;
51 struct mce *m = &dm->m;
52 int cpu = m->extcpu;
53
54 inject_mce(m);
55 if (m->status & MCI_STATUS_UC) {
56 struct pt_regs regs;
57 memset(®s, 0, sizeof(struct pt_regs));
58 regs.ip = m->ip;
59 regs.cs = m->cs;
60 printk(KERN_INFO "Triggering MCE exception on CPU %d\n", cpu);
61 do_machine_check(®s, 0);
62 printk(KERN_INFO "MCE exception done on CPU %d\n", cpu);
63 } else {
64 mce_banks_t b;
65 memset(&b, 0xff, sizeof(mce_banks_t));
66 printk(KERN_INFO "Starting machine check poll CPU %d\n", cpu);
67 machine_check_poll(0, &b);
68 mce_notify_irq();
69 printk(KERN_INFO "Finished machine check poll on CPU %d\n",
70 cpu);
71 }
72 kfree(dm);
73 }
74
75 /* Error injection interface */
76 static ssize_t mce_write(struct file *filp, const char __user *ubuf,
77 size_t usize, loff_t *off)
78 {
79 struct delayed_mce *dm;
80 struct mce m;
81
82 if (!capable(CAP_SYS_ADMIN))
83 return -EPERM;
84 /*
85 * There are some cases where real MSR reads could slip
86 * through.
87 */
88 if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
89 return -EIO;
90
91 if ((unsigned long)usize > sizeof(struct mce))
92 usize = sizeof(struct mce);
93 if (copy_from_user(&m, ubuf, usize))
94 return -EFAULT;
95
96 if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
97 return -EINVAL;
98
99 dm = kmalloc(sizeof(struct delayed_mce), GFP_KERNEL);
100 if (!dm)
101 return -ENOMEM;
102
103 /*
104 * Need to give user space some time to set everything up,
105 * so do it a jiffie or two later everywhere.
106 * Should we use a hrtimer here for better synchronization?
107 */
108 memcpy(&dm->m, &m, sizeof(struct mce));
109 setup_timer(&dm->timer, raise_mce, (unsigned long)dm);
110 dm->timer.expires = jiffies + 2;
111 add_timer_on(&dm->timer, m.extcpu);
112 return usize;
113 }
114
115 static int inject_init(void)
116 {
117 printk(KERN_INFO "Machine check injector initialized\n");
118 mce_chrdev_ops.write = mce_write;
119 return 0;
120 }
121
122 module_init(inject_init);
123 /*
124 * Cannot tolerate unloading currently because we cannot
125 * guarantee all openers of mce_chrdev will get a reference to us.
126 */
127 MODULE_LICENSE("GPL");
128
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