101 lines
2.3 KiB
C
101 lines
2.3 KiB
C
|
/*
|
||
|
|
* Copyright 2014 Google, Inc.
|
||
|
|
*
|
||
|
|
* This software is licensed under the terms of the GNU General Public
|
||
|
|
* License version 2, as published by the Free Software Foundation, and
|
||
|
|
* may be copied, distributed, and modified under those terms.
|
||
|
|
*
|
||
|
|
* This program is distributed in the hope that it will be useful,
|
||
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
|
* GNU General Public License for more details.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/cdev.h>
|
||
|
|
#include <linux/device.h>
|
||
|
|
#include <linux/fs.h>
|
||
|
|
#include <linux/uaccess.h>
|
||
|
|
#include <linux/vmalloc.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)
|
||
|
|
{
|
||
|
|
u64 id;
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
if (!count)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
/* check outside lock, page in any data. write_buf_user also checks */
|
||
|
|
if (!access_ok(VERIFY_READ, buf, count))
|
||
|
|
return -EFAULT;
|
||
|
|
|
||
|
|
mutex_lock(&pmsg_lock);
|
||
|
|
ret = psinfo->write_buf_user(PSTORE_TYPE_PMSG, 0, &id, 0, buf, 0, count,
|
||
|
|
psinfo);
|
||
|
|
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(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(THIS_MODULE, 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);
|
||
|
|
}
|