5113f6f70
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kernel add
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/*
* 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);
#define PMSG_MAX_BOUNCE_BUFFER_SIZE (2*PAGE_SIZE)
static ssize_t write_pmsg(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
size_t i, buffer_size;
char *buffer;
if (!count)
return 0;
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
buffer_size = count;
if (buffer_size > PMSG_MAX_BOUNCE_BUFFER_SIZE)
buffer_size = PMSG_MAX_BOUNCE_BUFFER_SIZE;
buffer = vmalloc(buffer_size);
if (!buffer)
return -ENOMEM;
mutex_lock(&pmsg_lock);
for (i = 0; i < count; ) {
size_t c = min(count - i, buffer_size);
u64 id;
long ret;
ret = __copy_from_user(buffer, buf + i, c);
if (unlikely(ret != 0)) {
mutex_unlock(&pmsg_lock);
vfree(buffer);
return -EFAULT;
}
psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, 0, buffer, 0, c,
psinfo);
i += c;
}
mutex_unlock(&pmsg_lock);
vfree(buffer);
return 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
");
goto err;
}
pmsg_class = class_create(THIS_MODULE, PMSG_NAME);
if (IS_ERR(pmsg_class)) {
pr_err("device class file already in use
");
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
");
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);
}
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