1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
/*
* 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/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 int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
{
int cpu = smp_processor_id();
struct mce *m = &__get_cpu_var(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;
}
/* Inject mce on current CPU */
static int raise_local(void)
{
struct mce *m = &__get_cpu_var(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_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))
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 NMI %lx\n",
*cpumask_bits(mce_inject_cpumask));
break;
}
cpu_relax();
}
raise_local();
put_cpu();
put_online_cpus();
} else
#endif
raise_local();
}
/* 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);
raise_mce(&m);
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");
|
