linux/arch/x86/kernel/cpu/mce/dev-mcelog.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * /dev/mcelog driver
 *
 * K8 parts Copyright 2002,2003 Andi Kleen, SuSE Labs.
 * Rest from unknown author(s).
 * 2004 Andi Kleen. Rewrote most of it.
 * Copyright 2008 Intel Corporation
 * Author: Andi Kleen
 */

#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/poll.h>

#include "internal.h"

static BLOCKING_NOTIFIER_HEAD(mce_injector_chain);

static DEFINE_MUTEX(mce_chrdev_read_mutex);

static char mce_helper[128];
static char *mce_helper_argv[2] = …;

/*
 * Lockless MCE logging infrastructure.
 * This avoids deadlocks on printk locks without having to break locks. Also
 * separate MCEs from kernel messages to avoid bogus bug reports.
 */

static struct mce_log_buffer *mcelog;

static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait);

static int dev_mce_log(struct notifier_block *nb, unsigned long val,
				void *data)
{ … }

static struct notifier_block dev_mcelog_nb = …;

static void mce_do_trigger(struct work_struct *work)
{ … }

static DECLARE_WORK(mce_trigger_work, mce_do_trigger);


void mce_work_trigger(void)
{ … }

static ssize_t
show_trigger(struct device *s, struct device_attribute *attr, char *buf)
{ … }

static ssize_t set_trigger(struct device *s, struct device_attribute *attr,
				const char *buf, size_t siz)
{ … }

DEVICE_ATTR(…);

/*
 * mce_chrdev: Character device /dev/mcelog to read and clear the MCE log.
 */

static DEFINE_SPINLOCK(mce_chrdev_state_lock);
static int mce_chrdev_open_count;	/* #times opened */
static int mce_chrdev_open_exclu;	/* already open exclusive? */

static int mce_chrdev_open(struct inode *inode, struct file *file)
{ … }

static int mce_chrdev_release(struct inode *inode, struct file *file)
{ … }

static int mce_apei_read_done;

/* Collect MCE record of previous boot in persistent storage via APEI ERST. */
static int __mce_read_apei(char __user **ubuf, size_t usize)
{ … }

static ssize_t mce_chrdev_read(struct file *filp, char __user *ubuf,
				size_t usize, loff_t *off)
{ … }

static __poll_t mce_chrdev_poll(struct file *file, poll_table *wait)
{ … }

static long mce_chrdev_ioctl(struct file *f, unsigned int cmd,
				unsigned long arg)
{ … }

void mce_register_injector_chain(struct notifier_block *nb)
{ … }
EXPORT_SYMBOL_GPL(…);

void mce_unregister_injector_chain(struct notifier_block *nb)
{ … }
EXPORT_SYMBOL_GPL(…);

static ssize_t mce_chrdev_write(struct file *filp, const char __user *ubuf,
				size_t usize, loff_t *off)
{ … }

static const struct file_operations mce_chrdev_ops = …;

static struct miscdevice mce_chrdev_device = …;

static __init int dev_mcelog_init_device(void)
{ … }
device_initcall_sync(dev_mcelog_init_device);