424 lines
11 KiB
C
424 lines
11 KiB
C
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/*
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* MCE grading rules.
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* Copyright 2008, 2009 Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*
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* Author: Andi Kleen
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*/
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#include <linux/kernel.h>
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#include <linux/seq_file.h>
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#include <linux/init.h>
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#include <linux/debugfs.h>
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#include <asm/mce.h>
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#include <linux/uaccess.h>
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#include "mce-internal.h"
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/*
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* Grade an mce by severity. In general the most severe ones are processed
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* first. Since there are quite a lot of combinations test the bits in a
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* table-driven way. The rules are simply processed in order, first
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* match wins.
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*
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* Note this is only used for machine check exceptions, the corrected
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* errors use much simpler rules. The exceptions still check for the corrected
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* errors, but only to leave them alone for the CMCI handler (except for
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* panic situations)
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*/
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enum context { IN_KERNEL = 1, IN_USER = 2, IN_KERNEL_RECOV = 3 };
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enum ser { SER_REQUIRED = 1, NO_SER = 2 };
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enum exception { EXCP_CONTEXT = 1, NO_EXCP = 2 };
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static struct severity {
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u64 mask;
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u64 result;
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unsigned char sev;
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unsigned char mcgmask;
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unsigned char mcgres;
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unsigned char ser;
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unsigned char context;
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unsigned char excp;
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unsigned char covered;
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char *msg;
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} severities[] = {
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#define MCESEV(s, m, c...) { .sev = MCE_ ## s ## _SEVERITY, .msg = m, ## c }
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#define KERNEL .context = IN_KERNEL
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#define USER .context = IN_USER
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#define KERNEL_RECOV .context = IN_KERNEL_RECOV
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#define SER .ser = SER_REQUIRED
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#define NOSER .ser = NO_SER
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#define EXCP .excp = EXCP_CONTEXT
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#define NOEXCP .excp = NO_EXCP
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#define BITCLR(x) .mask = x, .result = 0
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#define BITSET(x) .mask = x, .result = x
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#define MCGMASK(x, y) .mcgmask = x, .mcgres = y
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#define MASK(x, y) .mask = x, .result = y
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#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
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#define MCI_UC_AR (MCI_STATUS_UC|MCI_STATUS_AR)
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#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
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#define MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
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MCESEV(
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NO, "Invalid",
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BITCLR(MCI_STATUS_VAL)
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),
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MCESEV(
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NO, "Not enabled",
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EXCP, BITCLR(MCI_STATUS_EN)
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),
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MCESEV(
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PANIC, "Processor context corrupt",
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BITSET(MCI_STATUS_PCC)
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),
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/* When MCIP is not set something is very confused */
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MCESEV(
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PANIC, "MCIP not set in MCA handler",
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EXCP, MCGMASK(MCG_STATUS_MCIP, 0)
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),
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/* Neither return not error IP -- no chance to recover -> PANIC */
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MCESEV(
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PANIC, "Neither restart nor error IP",
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EXCP, MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
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),
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MCESEV(
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PANIC, "In kernel and no restart IP",
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EXCP, KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
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),
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MCESEV(
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PANIC, "In kernel and no restart IP",
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EXCP, KERNEL_RECOV, MCGMASK(MCG_STATUS_RIPV, 0)
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),
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MCESEV(
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DEFERRED, "Deferred error",
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NOSER, MASK(MCI_STATUS_UC|MCI_STATUS_DEFERRED|MCI_STATUS_POISON, MCI_STATUS_DEFERRED)
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),
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MCESEV(
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KEEP, "Corrected error",
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NOSER, BITCLR(MCI_STATUS_UC)
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),
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/*
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* known AO MCACODs reported via MCE or CMC:
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*
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* SRAO could be signaled either via a machine check exception or
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* CMCI with the corresponding bit S 1 or 0. So we don't need to
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* check bit S for SRAO.
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*/
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MCESEV(
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AO, "Action optional: memory scrubbing error",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_AR|MCACOD_SCRUBMSK, MCI_STATUS_UC|MCACOD_SCRUB)
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),
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MCESEV(
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AO, "Action optional: last level cache writeback error",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_AR|MCACOD, MCI_STATUS_UC|MCACOD_L3WB)
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),
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/* ignore OVER for UCNA */
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MCESEV(
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UCNA, "Uncorrected no action required",
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SER, MASK(MCI_UC_SAR, MCI_STATUS_UC)
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),
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MCESEV(
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PANIC, "Illegal combination (UCNA with AR=1)",
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SER,
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MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR)
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),
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MCESEV(
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KEEP, "Non signalled machine check",
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SER, BITCLR(MCI_STATUS_S)
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),
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MCESEV(
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PANIC, "Action required with lost events",
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SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR)
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),
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/* known AR MCACODs: */
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#ifdef CONFIG_MEMORY_FAILURE
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MCESEV(
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KEEP, "Action required but unaffected thread is continuable",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR, MCI_UC_SAR|MCI_ADDR),
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MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, MCG_STATUS_RIPV)
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),
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MCESEV(
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AR, "Action required: data load in error recoverable area of kernel",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
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KERNEL_RECOV
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),
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MCESEV(
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AR, "Action required: data load error in a user process",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
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USER
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),
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MCESEV(
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AR, "Action required: instruction fetch error in a user process",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR),
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USER
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),
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MCESEV(
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PANIC, "Data load in unrecoverable area of kernel",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
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KERNEL
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),
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MCESEV(
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PANIC, "Instruction fetch error in kernel",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR),
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KERNEL
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),
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#endif
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MCESEV(
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PANIC, "Action required: unknown MCACOD",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)
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),
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MCESEV(
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SOME, "Action optional: unknown MCACOD",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S)
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),
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MCESEV(
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SOME, "Action optional with lost events",
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SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_S)
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),
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MCESEV(
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PANIC, "Overflowed uncorrected",
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BITSET(MCI_STATUS_OVER|MCI_STATUS_UC)
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),
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MCESEV(
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UC, "Uncorrected",
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BITSET(MCI_STATUS_UC)
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),
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MCESEV(
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SOME, "No match",
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BITSET(0)
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) /* always matches. keep at end */
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};
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#define mc_recoverable(mcg) (((mcg) & (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) == \
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(MCG_STATUS_RIPV|MCG_STATUS_EIPV))
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/*
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* If mcgstatus indicated that ip/cs on the stack were
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* no good, then "m->cs" will be zero and we will have
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* to assume the worst case (IN_KERNEL) as we actually
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* have no idea what we were executing when the machine
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* check hit.
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* If we do have a good "m->cs" (or a faked one in the
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* case we were executing in VM86 mode) we can use it to
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* distinguish an exception taken in user from from one
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* taken in the kernel.
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*/
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static int error_context(struct mce *m)
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{
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if ((m->cs & 3) == 3)
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return IN_USER;
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if (mc_recoverable(m->mcgstatus) && ex_has_fault_handler(m->ip))
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return IN_KERNEL_RECOV;
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return IN_KERNEL;
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}
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static int mce_severity_amd_smca(struct mce *m, enum context err_ctx)
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{
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u32 addr = MSR_AMD64_SMCA_MCx_CONFIG(m->bank);
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u32 low, high;
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/*
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* We need to look at the following bits:
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* - "succor" bit (data poisoning support), and
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* - TCC bit (Task Context Corrupt)
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* in MCi_STATUS to determine error severity.
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*/
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if (!mce_flags.succor)
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return MCE_PANIC_SEVERITY;
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if (rdmsr_safe(addr, &low, &high))
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return MCE_PANIC_SEVERITY;
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/* TCC (Task context corrupt). If set and if IN_KERNEL, panic. */
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if ((low & MCI_CONFIG_MCAX) &&
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(m->status & MCI_STATUS_TCC) &&
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(err_ctx == IN_KERNEL))
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return MCE_PANIC_SEVERITY;
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/* ...otherwise invoke hwpoison handler. */
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return MCE_AR_SEVERITY;
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}
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/*
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* See AMD Error Scope Hierarchy table in a newer BKDG. For example
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* 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features"
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*/
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static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_excp)
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{
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enum context ctx = error_context(m);
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/* Processor Context Corrupt, no need to fumble too much, die! */
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if (m->status & MCI_STATUS_PCC)
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return MCE_PANIC_SEVERITY;
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if (m->status & MCI_STATUS_UC) {
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if (ctx == IN_KERNEL)
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return MCE_PANIC_SEVERITY;
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/*
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* On older systems where overflow_recov flag is not present, we
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* should simply panic if an error overflow occurs. If
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* overflow_recov flag is present and set, then software can try
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* to at least kill process to prolong system operation.
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*/
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if (mce_flags.overflow_recov) {
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if (mce_flags.smca)
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return mce_severity_amd_smca(m, ctx);
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/* kill current process */
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return MCE_AR_SEVERITY;
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} else {
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/* at least one error was not logged */
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if (m->status & MCI_STATUS_OVER)
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return MCE_PANIC_SEVERITY;
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}
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/*
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* For any other case, return MCE_UC_SEVERITY so that we log the
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* error and exit #MC handler.
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*/
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return MCE_UC_SEVERITY;
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}
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/*
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* deferred error: poll handler catches these and adds to mce_ring so
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* memory-failure can take recovery actions.
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*/
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if (m->status & MCI_STATUS_DEFERRED)
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return MCE_DEFERRED_SEVERITY;
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/*
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* corrected error: poll handler catches these and passes responsibility
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* of decoding the error to EDAC
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*/
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return MCE_KEEP_SEVERITY;
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}
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static int mce_severity_intel(struct mce *m, int tolerant, char **msg, bool is_excp)
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{
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enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP);
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enum context ctx = error_context(m);
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struct severity *s;
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for (s = severities;; s++) {
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if ((m->status & s->mask) != s->result)
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continue;
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if ((m->mcgstatus & s->mcgmask) != s->mcgres)
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continue;
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if (s->ser == SER_REQUIRED && !mca_cfg.ser)
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continue;
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if (s->ser == NO_SER && mca_cfg.ser)
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continue;
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if (s->context && ctx != s->context)
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continue;
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if (s->excp && excp != s->excp)
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continue;
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if (msg)
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*msg = s->msg;
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s->covered = 1;
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if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) {
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if (tolerant < 1)
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return MCE_PANIC_SEVERITY;
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}
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return s->sev;
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}
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}
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/* Default to mce_severity_intel */
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int (*mce_severity)(struct mce *m, int tolerant, char **msg, bool is_excp) =
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mce_severity_intel;
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void __init mcheck_vendor_init_severity(void)
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{
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if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
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mce_severity = mce_severity_amd;
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}
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#ifdef CONFIG_DEBUG_FS
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static void *s_start(struct seq_file *f, loff_t *pos)
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{
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if (*pos >= ARRAY_SIZE(severities))
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||
|
|
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 */
|