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 32enum context { IN_KERNEL = 1, IN_USER = 2 }; 33enum ser { SER_REQUIRED = 1, NO_SER = 2 }; 34 35static 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 KERNEL .context = IN_KERNEL 47#define USER .context = IN_USER 48#define SER .ser = SER_REQUIRED 49#define NOSER .ser = NO_SER 50#define SEV(s) .sev = MCE_ ## s ## _SEVERITY 51#define BITCLR(x, s, m, r...) { .mask = x, .result = 0, SEV(s), .msg = m, ## r } 52#define BITSET(x, s, m, r...) { .mask = x, .result = x, SEV(s), .msg = m, ## r } 53#define MCGMASK(x, res, s, m, r...) \ 54 { .mcgmask = x, .mcgres = res, SEV(s), .msg = m, ## r } 55#define MASK(x, y, s, m, r...) \ 56 { .mask = x, .result = y, SEV(s), .msg = m, ## r } 57#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S) 58#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR) 59#define MCACOD 0xffff 60 61 BITCLR(MCI_STATUS_VAL, NO, "Invalid"), 62 BITCLR(MCI_STATUS_EN, NO, "Not enabled"), 63 BITSET(MCI_STATUS_PCC, PANIC, "Processor context corrupt"), 64 /* When MCIP is not set something is very confused */ 65 MCGMASK(MCG_STATUS_MCIP, 0, PANIC, "MCIP not set in MCA handler"), 66 /* Neither return not error IP -- no chance to recover -> PANIC */ 67 MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0, PANIC, 68 "Neither restart nor error IP"), 69 MCGMASK(MCG_STATUS_RIPV, 0, PANIC, "In kernel and no restart IP", 70 KERNEL), 71 BITCLR(MCI_STATUS_UC, KEEP, "Corrected error", NOSER), 72 MASK(MCI_STATUS_OVER|MCI_STATUS_UC|MCI_STATUS_EN, MCI_STATUS_UC, SOME, 73 "Spurious not enabled", SER), 74 75 /* ignore OVER for UCNA */ 76 MASK(MCI_UC_SAR, MCI_STATUS_UC, KEEP, 77 "Uncorrected no action required", SER), 78 MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR, PANIC, 79 "Illegal combination (UCNA with AR=1)", SER), 80 MASK(MCI_STATUS_S, 0, KEEP, "Non signalled machine check", SER), 81 82 /* AR add known MCACODs here */ 83 MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_SAR, PANIC, 84 "Action required with lost events", SER), 85 MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_SAR, PANIC, 86 "Action required; unknown MCACOD", SER), 87 88 /* known AO MCACODs: */ 89 MASK(MCI_UC_SAR|MCI_STATUS_OVER|0xfff0, MCI_UC_S|0xc0, AO, 90 "Action optional: memory scrubbing error", SER), 91 MASK(MCI_UC_SAR|MCI_STATUS_OVER|MCACOD, MCI_UC_S|0x17a, AO, 92 "Action optional: last level cache writeback error", SER), 93 94 MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S, SOME, 95 "Action optional unknown MCACOD", SER), 96 MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S|MCI_STATUS_OVER, SOME, 97 "Action optional with lost events", SER), 98 BITSET(MCI_STATUS_UC|MCI_STATUS_OVER, PANIC, "Overflowed uncorrected"), 99 BITSET(MCI_STATUS_UC, UC, "Uncorrected"), 100 BITSET(0, SOME, "No match") /* always matches. keep at end */ 101}; 102 103/* 104 * If the EIPV bit is set, it means the saved IP is the 105 * instruction which caused the MCE. 106 */ 107static int error_context(struct mce *m) 108{ 109 if (m->mcgstatus & MCG_STATUS_EIPV) 110 return (m->ip && (m->cs & 3) == 3) ? IN_USER : IN_KERNEL; 111 /* Unknown, assume kernel */ 112 return IN_KERNEL; 113} 114 115int mce_severity(struct mce *a, int tolerant, char **msg) 116{ 117 enum context ctx = error_context(a); 118 struct severity *s; 119 120 for (s = severities;; s++) { 121 if ((a->status & s->mask) != s->result) 122 continue; 123 if ((a->mcgstatus & s->mcgmask) != s->mcgres) 124 continue; 125 if (s->ser == SER_REQUIRED && !mce_ser) 126 continue; 127 if (s->ser == NO_SER && mce_ser) 128 continue; 129 if (s->context && ctx != s->context) 130 continue; 131 if (msg) 132 *msg = s->msg; 133 s->covered = 1; 134 if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) { 135 if (panic_on_oops || tolerant < 1) 136 return MCE_PANIC_SEVERITY; 137 } 138 return s->sev; 139 } 140} 141 142#ifdef CONFIG_DEBUG_FS 143static void *s_start(struct seq_file *f, loff_t *pos) 144{ 145 if (*pos >= ARRAY_SIZE(severities)) 146 return NULL; 147 return &severities[*pos]; 148} 149 150static void *s_next(struct seq_file *f, void *data, loff_t *pos) 151{ 152 if (++(*pos) >= ARRAY_SIZE(severities)) 153 return NULL; 154 return &severities[*pos]; 155} 156 157static void s_stop(struct seq_file *f, void *data) 158{ 159} 160 161static int s_show(struct seq_file *f, void *data) 162{ 163 struct severity *ser = data; 164 seq_printf(f, "%d\t%s\n", ser->covered, ser->msg); 165 return 0; 166} 167 168static const struct seq_operations severities_seq_ops = { 169 .start = s_start, 170 .next = s_next, 171 .stop = s_stop, 172 .show = s_show, 173}; 174 175static int severities_coverage_open(struct inode *inode, struct file *file) 176{ 177 return seq_open(file, &severities_seq_ops); 178} 179 180static ssize_t severities_coverage_write(struct file *file, 181 const char __user *ubuf, 182 size_t count, loff_t *ppos) 183{ 184 int i; 185 for (i = 0; i < ARRAY_SIZE(severities); i++) 186 severities[i].covered = 0; 187 return count; 188} 189 190static const struct file_operations severities_coverage_fops = { 191 .open = severities_coverage_open, 192 .release = seq_release, 193 .read = seq_read, 194 .write = severities_coverage_write, 195}; 196 197static int __init severities_debugfs_init(void) 198{ 199 struct dentry *dmce = NULL, *fseverities_coverage = NULL; 200 201 dmce = mce_get_debugfs_dir(); 202 if (dmce == NULL) 203 goto err_out; 204 fseverities_coverage = debugfs_create_file("severities-coverage", 205 0444, dmce, NULL, 206 &severities_coverage_fops); 207 if (fseverities_coverage == NULL) 208 goto err_out; 209 210 return 0; 211 212err_out: 213 return -ENOMEM; 214} 215late_initcall(severities_debugfs_init); 216#endif 217