arch/x86/kernel/cpu/mcheck/mce-severity.c

   1 /*
   2  * MCE grading rules.
   3  * Copyright 2008, 2009 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  * Author: Andi Kleen
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/init.h>
  15 #include <linux/debugfs.h>
  16 #include <asm/mce.h>
  17
  18 #include "mce-internal.h"
  19
  20 /*
  21  * Grade an mce by severity. In general the most severe ones are processed
  22  * first. Since there are quite a lot of combinations test the bits in a
  23  * table-driven way. The rules are simply processed in order, first
  24  * match wins.
  25  *
  26  * Note this is only used for machine check exceptions, the corrected
  27  * errors use much simpler rules. The exceptions still check for the corrected
  28  * errors, but only to leave them alone for the CMCI handler (except for
  29  * panic situations)
  30  */
  31
  32 enum context { IN_KERNEL = 1, IN_USER = 2 };
  33 enum ser { SER_REQUIRED = 1, NO_SER = 2 };
  34
  35 static struct severity {
  36         u64 mask;
  37         u64 result;
  38         unsigned char sev;
  39         unsigned char mcgmask;
  40         unsigned char mcgres;
  41         unsigned char ser;
  42         unsigned char context;
  43         unsigned char covered;
  44         char *msg;
  45 } severities[] = {
  46 #define MCESEV(s, m, c...) { .sev = MCE_ ## s ## _SEVERITY, .msg = m, ## c }
  47 #define  KERNEL         .context = IN_KERNEL
  48 #define  USER           .context = IN_USER
  49 #define  SER            .ser = SER_REQUIRED
  50 #define  NOSER          .ser = NO_SER
  51 #define  BITCLR(x)      .mask = x, .result = 0
  52 #define  BITSET(x)      .mask = x, .result = x
  53 #define  MCGMASK(x, y)  .mcgmask = x, .mcgres = y
  54 #define  MASK(x, y)     .mask = x, .result = y
  55 #define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
  56 #define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
  57 #define MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
  58 #define MCACOD 0xffff
  59 /* Architecturally defined codes from SDM Vol. 3B Chapter 15 */
  60 #define MCACOD_SCRUB    0x00C0  /* 0xC0-0xCF Memory Scrubbing */
  61 #define MCACOD_SCRUBMSK 0xfff0
  62 #define MCACOD_L3WB     0x017A  /* L3 Explicit Writeback */
  63 #define MCACOD_DATA     0x0134  /* Data Load */
  64 #define MCACOD_INSTR    0x0150  /* Instruction Fetch */
  65
  66         MCESEV(
  67                 NO, "Invalid",
  68                 BITCLR(MCI_STATUS_VAL)
  69                 ),
  70         MCESEV(
  71                 NO, "Not enabled",
  72                 BITCLR(MCI_STATUS_EN)
  73                 ),
  74         MCESEV(
  75                 PANIC, "Processor context corrupt",
  76                 BITSET(MCI_STATUS_PCC)
  77                 ),
  78         /* When MCIP is not set something is very confused */
  79         MCESEV(
  80                 PANIC, "MCIP not set in MCA handler",
  81                 MCGMASK(MCG_STATUS_MCIP, 0)
  82                 ),
  83         /* Neither return not error IP -- no chance to recover -> PANIC */
  84         MCESEV(
  85                 PANIC, "Neither restart nor error IP",
  86                 MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
  87                 ),
  88         MCESEV(
  89                 PANIC, "In kernel and no restart IP",
  90                 KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
  91                 ),
  92         MCESEV(
  93                 KEEP, "Corrected error",
  94                 NOSER, BITCLR(MCI_STATUS_UC)
  95                 ),
  96
  97         /* ignore OVER for UCNA */
  98         MCESEV(
  99                 KEEP, "Uncorrected no action required",
 100                 SER, MASK(MCI_UC_SAR, MCI_STATUS_UC)
 101                 ),
 102         MCESEV(
 103                 PANIC, "Illegal combination (UCNA with AR=1)",
 104                 SER,
 105                 MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR)
 106                 ),
 107         MCESEV(
 108                 KEEP, "Non signalled machine check",
 109                 SER, BITCLR(MCI_STATUS_S)
 110                 ),
 111
 112         MCESEV(
 113                 PANIC, "Action required with lost events",
 114                 SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR)
 115                 ),
 116
 117         /* known AR MCACODs: */
 118 #ifdef  CONFIG_MEMORY_FAILURE
 119         MCESEV(
 120                 KEEP, "HT thread notices Action required: data load error",
 121                 SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
 122                 MCGMASK(MCG_STATUS_EIPV, 0)
 123                 ),
 124         MCESEV(
 125                 AR, "Action required: data load error",
 126                 SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
 127                 USER
 128                 ),
 129 #endif
 130         MCESEV(
 131                 PANIC, "Action required: unknown MCACOD",
 132                 SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)
 133                 ),
 134
 135         /* known AO MCACODs: */
 136         MCESEV(
 137                 AO, "Action optional: memory scrubbing error",
 138                 SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD_SCRUBMSK, MCI_UC_S|MCACOD_SCRUB)
 139                 ),
 140         MCESEV(
 141                 AO, "Action optional: last level cache writeback error",
 142                 SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_S|MCACOD_L3WB)
 143                 ),
 144         MCESEV(
 145                 SOME, "Action optional: unknown MCACOD",
 146                 SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S)
 147                 ),
 148         MCESEV(
 149                 SOME, "Action optional with lost events",
 150                 SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_S)
 151                 ),
 152
 153         MCESEV(
 154                 PANIC, "Overflowed uncorrected",
 155                 BITSET(MCI_STATUS_OVER|MCI_STATUS_UC)
 156                 ),
 157         MCESEV(
 158                 UC, "Uncorrected",
 159                 BITSET(MCI_STATUS_UC)
 160                 ),
 161         MCESEV(
 162                 SOME, "No match",
 163                 BITSET(0)
 164                 )       /* always matches. keep at end */
 165 };
 166
 167 /*
 168  * If the EIPV bit is set, it means the saved IP is the
 169  * instruction which caused the MCE.
 170  */
 171 static int error_context(struct mce *m)
 172 {
 173         if (m->mcgstatus & MCG_STATUS_EIPV)
 174                 return (m->ip && (m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
 175         /* Unknown, assume kernel */
 176         return IN_KERNEL;
 177 }
 178
 179 int mce_severity(struct mce *m, int tolerant, char **msg)
 180 {
 181         enum context ctx = error_context(m);
 182         struct severity *s;
 183
 184         for (s = severities;; s++) {
 185                 if ((m->status & s->mask) != s->result)
 186                         continue;
 187                 if ((m->mcgstatus & s->mcgmask) != s->mcgres)
 188                         continue;
 189                 if (s->ser == SER_REQUIRED && !mce_ser)
 190                         continue;
 191                 if (s->ser == NO_SER && mce_ser)
 192                         continue;
 193                 if (s->context && ctx != s->context)
 194                         continue;
 195                 if (msg)
 196                         *msg = s->msg;
 197                 s->covered = 1;
 198                 if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) {
 199                         if (panic_on_oops || tolerant < 1)
 200                                 return MCE_PANIC_SEVERITY;
 201                 }
 202                 return s->sev;
 203         }
 204 }
 205
 206 #ifdef CONFIG_DEBUG_FS
 207 static void *s_start(struct seq_file *f, loff_t *pos)
 208 {
 209         if (*pos >= ARRAY_SIZE(severities))
 210                 return NULL;
 211         return &severities[*pos];
 212 }
 213
 214 static void *s_next(struct seq_file *f, void *data, loff_t *pos)
 215 {
 216         if (++(*pos) >= ARRAY_SIZE(severities))
 217                 return NULL;
 218         return &severities[*pos];
 219 }
 220
 221 static void s_stop(struct seq_file *f, void *data)
 222 {
 223 }
 224
 225 static int s_show(struct seq_file *f, void *data)
 226 {
 227         struct severity *ser = data;
 228         seq_printf(f, "%d\t%s\n", ser->covered, ser->msg);
 229         return 0;
 230 }
 231
 232 static const struct seq_operations severities_seq_ops = {
 233         .start  = s_start,
 234         .next   = s_next,
 235         .stop   = s_stop,
 236         .show   = s_show,
 237 };
 238
 239 static int severities_coverage_open(struct inode *inode, struct file *file)
 240 {
 241         return seq_open(file, &severities_seq_ops);
 242 }
 243
 244 static ssize_t severities_coverage_write(struct file *file,
 245                                          const char __user *ubuf,
 246                                          size_t count, loff_t *ppos)
 247 {
 248         int i;
 249         for (i = 0; i < ARRAY_SIZE(severities); i++)
 250                 severities[i].covered = 0;
 251         return count;
 252 }
 253
 254 static const struct file_operations severities_coverage_fops = {
 255         .open           = severities_coverage_open,
 256         .release        = seq_release,
 257         .read           = seq_read,
 258         .write          = severities_coverage_write,
 259         .llseek         = seq_lseek,
 260 };
 261
 262 static int __init severities_debugfs_init(void)
 263 {
 264         struct dentry *dmce, *fsev;
 265
 266         dmce = mce_get_debugfs_dir();
 267         if (!dmce)
 268                 goto err_out;
 269
 270         fsev = debugfs_create_file("severities-coverage", 0444, dmce, NULL,
 271                                    &severities_coverage_fops);
 272         if (!fsev)
 273                 goto err_out;
 274
 275         return 0;
 276
 277 err_out:
 278         return -ENOMEM;
 279 }
 280 late_initcall(severities_debugfs_init);
 281 #endif /* CONFIG_DEBUG_FS */