217 lines
6.2 KiB
C
217 lines
6.2 KiB
C
/*
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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 "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 };
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enum ser { SER_REQUIRED = 1, NO_SER = 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 covered;
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char *msg;
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} severities[] = {
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#define KERNEL .context = IN_KERNEL
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#define USER .context = IN_USER
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#define SER .ser = SER_REQUIRED
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#define NOSER .ser = NO_SER
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#define SEV(s) .sev = MCE_ ## s ## _SEVERITY
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#define BITCLR(x, s, m, r...) { .mask = x, .result = 0, SEV(s), .msg = m, ## r }
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#define BITSET(x, s, m, r...) { .mask = x, .result = x, SEV(s), .msg = m, ## r }
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#define MCGMASK(x, res, s, m, r...) \
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{ .mcgmask = x, .mcgres = res, SEV(s), .msg = m, ## r }
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#define MASK(x, y, s, m, r...) \
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{ .mask = x, .result = y, SEV(s), .msg = m, ## r }
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#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
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#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
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#define MCACOD 0xffff
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BITCLR(MCI_STATUS_VAL, NO, "Invalid"),
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BITCLR(MCI_STATUS_EN, NO, "Not enabled"),
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BITSET(MCI_STATUS_PCC, PANIC, "Processor context corrupt"),
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/* When MCIP is not set something is very confused */
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MCGMASK(MCG_STATUS_MCIP, 0, PANIC, "MCIP not set in MCA handler"),
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/* Neither return not error IP -- no chance to recover -> PANIC */
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MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0, PANIC,
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"Neither restart nor error IP"),
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MCGMASK(MCG_STATUS_RIPV, 0, PANIC, "In kernel and no restart IP",
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KERNEL),
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BITCLR(MCI_STATUS_UC, KEEP, "Corrected error", NOSER),
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MASK(MCI_STATUS_OVER|MCI_STATUS_UC|MCI_STATUS_EN, MCI_STATUS_UC, SOME,
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"Spurious not enabled", SER),
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/* ignore OVER for UCNA */
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MASK(MCI_UC_SAR, MCI_STATUS_UC, KEEP,
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"Uncorrected no action required", SER),
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MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR, PANIC,
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"Illegal combination (UCNA with AR=1)", SER),
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MASK(MCI_STATUS_S, 0, KEEP, "Non signalled machine check", SER),
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/* AR add known MCACODs here */
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MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_SAR, PANIC,
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"Action required with lost events", SER),
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MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_SAR, PANIC,
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"Action required; unknown MCACOD", SER),
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/* known AO MCACODs: */
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MASK(MCI_UC_SAR|MCI_STATUS_OVER|0xfff0, MCI_UC_S|0xc0, AO,
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"Action optional: memory scrubbing error", SER),
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MASK(MCI_UC_SAR|MCI_STATUS_OVER|MCACOD, MCI_UC_S|0x17a, AO,
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"Action optional: last level cache writeback error", SER),
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MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S, SOME,
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"Action optional unknown MCACOD", SER),
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MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S|MCI_STATUS_OVER, SOME,
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"Action optional with lost events", SER),
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BITSET(MCI_STATUS_UC|MCI_STATUS_OVER, PANIC, "Overflowed uncorrected"),
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BITSET(MCI_STATUS_UC, UC, "Uncorrected"),
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BITSET(0, SOME, "No match") /* always matches. keep at end */
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};
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/*
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* If the EIPV bit is set, it means the saved IP is the
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* instruction which caused the MCE.
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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->mcgstatus & MCG_STATUS_EIPV)
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return (m->ip && (m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
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/* Unknown, assume kernel */
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return IN_KERNEL;
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}
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int mce_severity(struct mce *a, int tolerant, char **msg)
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{
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enum context ctx = error_context(a);
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struct severity *s;
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for (s = severities;; s++) {
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if ((a->status & s->mask) != s->result)
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continue;
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if ((a->mcgstatus & s->mcgmask) != s->mcgres)
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continue;
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if (s->ser == SER_REQUIRED && !mce_ser)
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continue;
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if (s->ser == NO_SER && mce_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 (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 (panic_on_oops || 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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#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;
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return &severities[*pos];
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}
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static void *s_next(struct seq_file *f, void *data, loff_t *pos)
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{
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if (++(*pos) >= ARRAY_SIZE(severities))
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return NULL;
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return &severities[*pos];
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}
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static void s_stop(struct seq_file *f, void *data)
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{
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}
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static int s_show(struct seq_file *f, void *data)
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{
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struct severity *ser = data;
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seq_printf(f, "%d\t%s\n", ser->covered, ser->msg);
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return 0;
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}
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static const struct seq_operations severities_seq_ops = {
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.start = s_start,
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.next = s_next,
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.stop = s_stop,
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.show = s_show,
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};
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static int severities_coverage_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &severities_seq_ops);
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}
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static ssize_t severities_coverage_write(struct file *file,
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const char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(severities); i++)
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severities[i].covered = 0;
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return count;
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}
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static const struct file_operations severities_coverage_fops = {
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.open = severities_coverage_open,
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.release = seq_release,
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.read = seq_read,
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.write = severities_coverage_write,
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};
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static int __init severities_debugfs_init(void)
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{
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struct dentry *dmce = NULL, *fseverities_coverage = NULL;
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dmce = mce_get_debugfs_dir();
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if (dmce == NULL)
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goto err_out;
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fseverities_coverage = debugfs_create_file("severities-coverage",
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0444, dmce, NULL,
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&severities_coverage_fops);
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if (fseverities_coverage == NULL)
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goto err_out;
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return 0;
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err_out:
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return -ENOMEM;
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}
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late_initcall(severities_debugfs_init);
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#endif
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