[linux-2.6-block.git] / fs / pstore / pmsg.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);
}
Commit	Line	Data
9d5438f4 MS	1	/*
	2	* Copyright 2014 Google, Inc.
	3	*
	4	* This software is licensed under the terms of the GNU General Public
	5	* License version 2, as published by the Free Software Foundation, and
	6	* may be copied, distributed, and modified under those terms.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
	12	*/
	13
	14	#include <linux/cdev.h>
	15	#include <linux/device.h>
	16	#include <linux/fs.h>
	17	#include <linux/uaccess.h>
	18	#include <linux/vmalloc.h>
	19	#include "internal.h"
	20
	21	static DEFINE_MUTEX(pmsg_lock);
	22	#define PMSG_MAX_BOUNCE_BUFFER_SIZE (2*PAGE_SIZE)
	23
	24	static ssize_t write_pmsg(struct file file, const char __user buf,
	25	size_t count, loff_t *ppos)
	26	{
	27	size_t i, buffer_size;
	28	char *buffer;
	29
	30	if (!count)
	31	return 0;
	32
	33	if (!access_ok(VERIFY_READ, buf, count))
	34	return -EFAULT;
	35
	36	buffer_size = count;
	37	if (buffer_size > PMSG_MAX_BOUNCE_BUFFER_SIZE)
	38	buffer_size = PMSG_MAX_BOUNCE_BUFFER_SIZE;
	39	buffer = vmalloc(buffer_size);
549b39a9 GT	40	if (!buffer)
549b39a9 GT	41	return -ENOMEM;
9d5438f4 MS	42
	43	mutex_lock(&pmsg_lock);
	44	for (i = 0; i < count; ) {
	45	size_t c = min(count - i, buffer_size);
	46	u64 id;
	47	long ret;
	48
	49	ret = __copy_from_user(buffer, buf + i, c);
	50	if (unlikely(ret != 0)) {
	51	mutex_unlock(&pmsg_lock);
	52	vfree(buffer);
	53	return -EFAULT;
	54	}
	55	psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, 0, buffer, 0, c,
	56	psinfo);
	57
	58	i += c;
	59	}
	60
	61	mutex_unlock(&pmsg_lock);
	62	vfree(buffer);
	63	return count;
	64	}
	65
	66	static const struct file_operations pmsg_fops = {
	67	.owner = THIS_MODULE,
	68	.llseek = noop_llseek,
	69	.write = write_pmsg,
	70	};
	71
	72	static struct class *pmsg_class;
	73	static int pmsg_major;
	74	#define PMSG_NAME "pmsg"
	75	#undef pr_fmt
	76	#define pr_fmt(fmt) PMSG_NAME ": " fmt
	77
	78	static char pmsg_devnode(struct device dev, umode_t *mode)
	79	{
	80	if (mode)
	81	*mode = 0220;
	82	return NULL;
	83	}
	84
	85	void pstore_register_pmsg(void)
	86	{
	87	struct device *pmsg_device;
	88
	89	pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops);
	90	if (pmsg_major < 0) {
	91	pr_err("register_chrdev failed\n");
	92	goto err;
	93	}
	94
	95	pmsg_class = class_create(THIS_MODULE, PMSG_NAME);
	96	if (IS_ERR(pmsg_class)) {
	97	pr_err("device class file already in use\n");
	98	goto err_class;
	99	}
	100	pmsg_class->devnode = pmsg_devnode;
	101
	102	pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0),
	103	NULL, "%s%d", PMSG_NAME, 0);
	104	if (IS_ERR(pmsg_device)) {
	105	pr_err("failed to create device\n");
106	goto err_device;
107	}
108	return;
109
110	err_device:
111	class_destroy(pmsg_class);
112	err_class:
113	unregister_chrdev(pmsg_major, PMSG_NAME);
114	err:
115	return;
116	}
ee1d2674 GT	117
	118	void pstore_unregister_pmsg(void)
	119	{
	120	device_destroy(pmsg_class, MKDEV(pmsg_major, 0));
	121	class_destroy(pmsg_class);
	122	unregister_chrdev(pmsg_major, PMSG_NAME);
	123	}