mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-26 05:34:13 +08:00
ee1d267423
pstore doesn't support unregistering yet. It was marked as TODO. This patch adds some code to fix it: 1) Add functions to unregister kmsg/console/ftrace/pmsg. 2) Add a function to free compression buffer. 3) Unmap the memory and free it. 4) Add a function to unregister pstore filesystem. Signed-off-by: Geliang Tang <geliangtang@163.com> Acked-by: Kees Cook <keescook@chromium.org> [Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann] Signed-off-by: Tony Luck <tony.luck@intel.com>
124 lines
2.7 KiB
C
124 lines
2.7 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);
|
|
#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\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);
|
|
}
|