![Jarkko Nikula](/assets/img/avatar_default.png)
There is no need to carry potentially outdated Free Software Foundation mailing address in file headers since the COPYING file includes it. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
240 lines
5.2 KiB
C
240 lines
5.2 KiB
C
/*
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* APEI Error Record Serialization Table debug support
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*
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* ERST is a way provided by APEI to save and retrieve hardware error
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* information to and from a persistent store. This file provide the
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* debugging/testing support for ERST kernel support and firmware
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* implementation.
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*
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* Copyright 2010 Intel Corp.
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* Author: Huang Ying <ying.huang@intel.com>
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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 version
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* 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/uaccess.h>
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#include <acpi/apei.h>
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#include <linux/miscdevice.h>
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#include "apei-internal.h"
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#define ERST_DBG_PFX "ERST DBG: "
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#define ERST_DBG_RECORD_LEN_MAX 0x4000
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static void *erst_dbg_buf;
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static unsigned int erst_dbg_buf_len;
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/* Prevent erst_dbg_read/write from being invoked concurrently */
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static DEFINE_MUTEX(erst_dbg_mutex);
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static int erst_dbg_open(struct inode *inode, struct file *file)
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{
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int rc, *pos;
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if (erst_disable)
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return -ENODEV;
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pos = (int *)&file->private_data;
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rc = erst_get_record_id_begin(pos);
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if (rc)
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return rc;
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return nonseekable_open(inode, file);
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}
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static int erst_dbg_release(struct inode *inode, struct file *file)
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{
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erst_get_record_id_end();
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return 0;
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}
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static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
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{
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int rc;
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u64 record_id;
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u32 record_count;
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switch (cmd) {
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case APEI_ERST_CLEAR_RECORD:
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rc = copy_from_user(&record_id, (void __user *)arg,
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sizeof(record_id));
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if (rc)
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return -EFAULT;
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return erst_clear(record_id);
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case APEI_ERST_GET_RECORD_COUNT:
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rc = erst_get_record_count();
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if (rc < 0)
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return rc;
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record_count = rc;
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rc = put_user(record_count, (u32 __user *)arg);
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if (rc)
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return rc;
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return 0;
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default:
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return -ENOTTY;
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}
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}
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static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
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size_t usize, loff_t *off)
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{
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int rc, *pos;
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ssize_t len = 0;
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u64 id;
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if (*off)
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return -EINVAL;
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if (mutex_lock_interruptible(&erst_dbg_mutex) != 0)
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return -EINTR;
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pos = (int *)&filp->private_data;
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retry_next:
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rc = erst_get_record_id_next(pos, &id);
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if (rc)
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goto out;
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/* no more record */
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if (id == APEI_ERST_INVALID_RECORD_ID) {
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/*
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* If the persistent store is empty initially, the function
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* 'erst_read' below will return "-ENOENT" value. This causes
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* 'retry_next' label is entered again. The returned value
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* should be zero indicating the read operation is EOF.
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*/
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len = 0;
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goto out;
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}
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retry:
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rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
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/* The record may be cleared by others, try read next record */
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if (rc == -ENOENT)
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goto retry_next;
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if (rc < 0)
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goto out;
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if (len > ERST_DBG_RECORD_LEN_MAX) {
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pr_warning(ERST_DBG_PFX
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"Record (ID: 0x%llx) length is too long: %zd\n",
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id, len);
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rc = -EIO;
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goto out;
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}
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if (len > erst_dbg_buf_len) {
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void *p;
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rc = -ENOMEM;
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p = kmalloc(len, GFP_KERNEL);
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if (!p)
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goto out;
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kfree(erst_dbg_buf);
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erst_dbg_buf = p;
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erst_dbg_buf_len = len;
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goto retry;
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}
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rc = -EINVAL;
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if (len > usize)
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goto out;
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rc = -EFAULT;
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if (copy_to_user(ubuf, erst_dbg_buf, len))
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goto out;
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rc = 0;
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out:
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mutex_unlock(&erst_dbg_mutex);
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return rc ? rc : len;
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}
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static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf,
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size_t usize, loff_t *off)
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{
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int rc;
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struct cper_record_header *rcd;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if (usize > ERST_DBG_RECORD_LEN_MAX) {
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pr_err(ERST_DBG_PFX "Too long record to be written\n");
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return -EINVAL;
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}
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if (mutex_lock_interruptible(&erst_dbg_mutex))
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return -EINTR;
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if (usize > erst_dbg_buf_len) {
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void *p;
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rc = -ENOMEM;
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p = kmalloc(usize, GFP_KERNEL);
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if (!p)
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goto out;
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kfree(erst_dbg_buf);
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erst_dbg_buf = p;
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erst_dbg_buf_len = usize;
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}
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rc = copy_from_user(erst_dbg_buf, ubuf, usize);
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if (rc) {
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rc = -EFAULT;
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goto out;
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}
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rcd = erst_dbg_buf;
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rc = -EINVAL;
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if (rcd->record_length != usize)
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goto out;
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rc = erst_write(erst_dbg_buf);
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out:
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mutex_unlock(&erst_dbg_mutex);
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return rc < 0 ? rc : usize;
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}
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static const struct file_operations erst_dbg_ops = {
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.owner = THIS_MODULE,
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.open = erst_dbg_open,
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.release = erst_dbg_release,
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.read = erst_dbg_read,
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.write = erst_dbg_write,
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.unlocked_ioctl = erst_dbg_ioctl,
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.llseek = no_llseek,
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};
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static struct miscdevice erst_dbg_dev = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "erst_dbg",
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.fops = &erst_dbg_ops,
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};
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static __init int erst_dbg_init(void)
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{
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if (erst_disable) {
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pr_info(ERST_DBG_PFX "ERST support is disabled.\n");
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return -ENODEV;
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}
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return misc_register(&erst_dbg_dev);
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}
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static __exit void erst_dbg_exit(void)
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{
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misc_deregister(&erst_dbg_dev);
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kfree(erst_dbg_buf);
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}
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module_init(erst_dbg_init);
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module_exit(erst_dbg_exit);
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MODULE_AUTHOR("Huang Ying");
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MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support");
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MODULE_LICENSE("GPL");
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