summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/cpu/mcheck/mce-severity.c
blob: e2703520d1208539d21447d6f570a767b7e51f48 (plain)
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
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
/*
 * MCE grading rules.
 * Copyright 2008, 2009 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.
 *
 * Author: Andi Kleen
 */
#include <linux/kernel.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <asm/mce.h>

#include "mce-internal.h"

/*
 * Grade an mce by severity. In general the most severe ones are processed
 * first. Since there are quite a lot of combinations test the bits in a
 * table-driven way. The rules are simply processed in order, first
 * match wins.
 *
 * Note this is only used for machine check exceptions, the corrected
 * errors use much simpler rules. The exceptions still check for the corrected
 * errors, but only to leave them alone for the CMCI handler (except for
 * panic situations)
 */

enum context { IN_KERNEL = 1, IN_USER = 2 };
enum ser { SER_REQUIRED = 1, NO_SER = 2 };

static struct severity {
	u64 mask;
	u64 result;
	unsigned char sev;
	unsigned char mcgmask;
	unsigned char mcgres;
	unsigned char ser;
	unsigned char context;
	unsigned char covered;
	char *msg;
} severities[] = {
#define MCESEV(s, m, c...) { .sev = MCE_ ## s ## _SEVERITY, .msg = m, ## c }
#define  KERNEL		.context = IN_KERNEL
#define  USER		.context = IN_USER
#define  SER		.ser = SER_REQUIRED
#define  NOSER		.ser = NO_SER
#define  BITCLR(x)	.mask = x, .result = 0
#define  BITSET(x)	.mask = x, .result = x
#define  MCGMASK(x, y)	.mcgmask = x, .mcgres = y
#define  MASK(x, y)	.mask = x, .result = y
#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
#define	MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)

	MCESEV(
		NO, "Invalid",
		BITCLR(MCI_STATUS_VAL)
		),
	MCESEV(
		NO, "Not enabled",
		BITCLR(MCI_STATUS_EN)
		),
	MCESEV(
		PANIC, "Processor context corrupt",
		BITSET(MCI_STATUS_PCC)
		),
	/* When MCIP is not set something is very confused */
	MCESEV(
		PANIC, "MCIP not set in MCA handler",
		MCGMASK(MCG_STATUS_MCIP, 0)
		),
	/* Neither return not error IP -- no chance to recover -> PANIC */
	MCESEV(
		PANIC, "Neither restart nor error IP",
		MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
		),
	MCESEV(
		PANIC, "In kernel and no restart IP",
		KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
		),
	MCESEV(
		KEEP, "Corrected error",
		NOSER, BITCLR(MCI_STATUS_UC)
		),

	/* ignore OVER for UCNA */
	MCESEV(
		KEEP, "Uncorrected no action required",
		SER, MASK(MCI_UC_SAR, MCI_STATUS_UC)
		),
	MCESEV(
		PANIC, "Illegal combination (UCNA with AR=1)",
		SER,
		MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR)
		),
	MCESEV(
		KEEP, "Non signalled machine check",
		SER, BITCLR(MCI_STATUS_S)
		),

	MCESEV(
		PANIC, "Action required with lost events",
		SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR)
		),

	/* known AR MCACODs: */
#ifdef	CONFIG_MEMORY_FAILURE
	MCESEV(
		KEEP, "Action required but unaffected thread is continuable",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR),
		MCGMASK(MCG_STATUS_RIPV, MCG_STATUS_RIPV)
		),
	MCESEV(
		AR, "Action required: data load error in a user process",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
		USER
		),
	MCESEV(
		AR, "Action required: instruction fetch error in a user process",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR),
		USER
		),
#endif
	MCESEV(
		PANIC, "Action required: unknown MCACOD",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)
		),

	/* known AO MCACODs: */
	MCESEV(
		AO, "Action optional: memory scrubbing error",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD_SCRUBMSK, MCI_UC_S|MCACOD_SCRUB)
		),
	MCESEV(
		AO, "Action optional: last level cache writeback error",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_S|MCACOD_L3WB)
		),
	MCESEV(
		SOME, "Action optional: unknown MCACOD",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S)
		),
	MCESEV(
		SOME, "Action optional with lost events",
		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_S)
		),

	MCESEV(
		PANIC, "Overflowed uncorrected",
		BITSET(MCI_STATUS_OVER|MCI_STATUS_UC)
		),
	MCESEV(
		UC, "Uncorrected",
		BITSET(MCI_STATUS_UC)
		),
	MCESEV(
		SOME, "No match",
		BITSET(0)
		)	/* always matches. keep at end */
};

/*
 * If mcgstatus indicated that ip/cs on the stack were
 * no good, then "m->cs" will be zero and we will have
 * to assume the worst case (IN_KERNEL) as we actually
 * have no idea what we were executing when the machine
 * check hit.
 * If we do have a good "m->cs" (or a faked one in the
 * case we were executing in VM86 mode) we can use it to
 * distinguish an exception taken in user from from one
 * taken in the kernel.
 */
static int error_context(struct mce *m)
{
	return ((m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
}

int mce_severity(struct mce *m, int tolerant, char **msg)
{
	enum context ctx = error_context(m);
	struct severity *s;

	for (s = severities;; s++) {
		if ((m->status & s->mask) != s->result)
			continue;
		if ((m->mcgstatus & s->mcgmask) != s->mcgres)
			continue;
		if (s->ser == SER_REQUIRED && !mca_cfg.ser)
			continue;
		if (s->ser == NO_SER && mca_cfg.ser)
			continue;
		if (s->context && ctx != s->context)
			continue;
		if (msg)
			*msg = s->msg;
		s->covered = 1;
		if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) {
			if (panic_on_oops || tolerant < 1)
				return MCE_PANIC_SEVERITY;
		}
		return s->sev;
	}
}

#ifdef CONFIG_DEBUG_FS
static void *s_start(struct seq_file *f, loff_t *pos)
{
	if (*pos >= ARRAY_SIZE(severities))
		return NULL;
	return &severities[*pos];
}

static void *s_next(struct seq_file *f, void *data, loff_t *pos)
{
	if (++(*pos) >= ARRAY_SIZE(severities))
		return NULL;
	return &severities[*pos];
}

static void s_stop(struct seq_file *f, void *data)
{
}

static int s_show(struct seq_file *f, void *data)
{
	struct severity *ser = data;
	seq_printf(f, "%d\t%s\n", ser->covered, ser->msg);
	return 0;
}

static const struct seq_operations severities_seq_ops = {
	.start	= s_start,
	.next	= s_next,
	.stop	= s_stop,
	.show	= s_show,
};

static int severities_coverage_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &severities_seq_ops);
}

static ssize_t severities_coverage_write(struct file *file,
					 const char __user *ubuf,
					 size_t count, loff_t *ppos)
{
	int i;
	for (i = 0; i < ARRAY_SIZE(severities); i++)
		severities[i].covered = 0;
	return count;
}

static const struct file_operations severities_coverage_fops = {
	.open		= severities_coverage_open,
	.release	= seq_release,
	.read		= seq_read,
	.write		= severities_coverage_write,
	.llseek		= seq_lseek,
};

static int __init severities_debugfs_init(void)
{
	struct dentry *dmce, *fsev;

	dmce = mce_get_debugfs_dir();
	if (!dmce)
		goto err_out;

	fsev = debugfs_create_file("severities-coverage", 0444, dmce, NULL,
				   &severities_coverage_fops);
	if (!fsev)
		goto err_out;

	return 0;

err_out:
	return -ENOMEM;
}
late_initcall(severities_debugfs_init);
#endif /* CONFIG_DEBUG_FS */