// SPDX-License-Identifier: GPL-2.0-only/* * Copyright 2014  Google, Inc. */ #include <linux/cdev.h>#include <linux/device.h>#include <linux/fs.h>#include <linux/uaccess.h>#include "internal.h" static DEFINE_MUTEX(pmsg_lock); static ssize_t write_pmsg(struct file *file, const char __user *buf,			  size_t count, loff_t *ppos){	struct pstore_record record;	int ret; 	if (!count)		return 0; 	pstore_record_init(&record, psinfo);	record.type = PSTORE_TYPE_PMSG;	record.size = count; 	/* check outside lock, page in any data. write_user also checks */	if (!access_ok(buf, count))		return -EFAULT; 	mutex_lock(&pmsg_lock);	ret = psinfo->write_user(&record, buf);	mutex_unlock(&pmsg_lock);	return ret ? ret : count;} static const struct file_operations pmsg_fops = {	.owner		= THIS_MODULE,	.llseek		= noop_llseek,	.write		= write_pmsg,}; static struct class *pmsg_class;static int pmsg_major;#define PMSG_NAME "pmsg"#undef pr_fmt#define pr_fmt(fmt) PMSG_NAME ": " fmt static char *pmsg_devnode(const struct device *dev, umode_t *mode){	if (mode)		*mode = 0220;	return NULL;} void pstore_register_pmsg(void){	struct device *pmsg_device; 	pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops);	if (pmsg_major < 0) {		pr_err("register_chrdev failed\n");		goto err;	} 	pmsg_class = class_create(PMSG_NAME);	if (IS_ERR(pmsg_class)) {		pr_err("device class file already in use\n");		goto err_class;	}	pmsg_class->devnode = pmsg_devnode; 	pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0),					NULL, "%s%d", PMSG_NAME, 0);	if (IS_ERR(pmsg_device)) {		pr_err("failed to create device\n");		goto err_device;	}	return; err_device:	class_destroy(pmsg_class);err_class:	unregister_chrdev(pmsg_major, PMSG_NAME);err:	return;} void pstore_unregister_pmsg(void){	device_destroy(pmsg_class, MKDEV(pmsg_major, 0));	class_destroy(pmsg_class);	unregister_chrdev(pmsg_major, PMSG_NAME);}