[mirror_ubuntu-artful-kernel.git] / drivers / acpi / apei / erst-dbg.c

/*
 * APEI Error Record Serialization Table debug support
 *
 * ERST is a way provided by APEI to save and retrieve hardware error
 * infomation to and from a persistent store. This file provide the
 * debugging/testing support for ERST kernel support and firmware
 * implementation.
 *
 * Copyright 2010 Intel Corp.
 *   Author: Huang Ying <ying.huang@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <acpi/apei.h>
#include <linux/miscdevice.h>

#include "apei-internal.h"

#define ERST_DBG_PFX			"ERST DBG: "

#define ERST_DBG_RECORD_LEN_MAX		4096

static void *erst_dbg_buf;
static unsigned int erst_dbg_buf_len;

/* Prevent erst_dbg_read/write from being invoked concurrently */
static DEFINE_MUTEX(erst_dbg_mutex);

static int erst_dbg_open(struct inode *inode, struct file *file)
{
	if (erst_disable)
		return -ENODEV;

	return nonseekable_open(inode, file);
}

static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
{
	int rc;
	u64 record_id;
	u32 record_count;

	switch (cmd) {
	case APEI_ERST_CLEAR_RECORD:
		rc = copy_from_user(&record_id, (void __user *)arg,
				    sizeof(record_id));
		if (rc)
			return -EFAULT;
		return erst_clear(record_id);
	case APEI_ERST_GET_RECORD_COUNT:
		rc = erst_get_record_count();
		if (rc < 0)
			return rc;
		record_count = rc;
		rc = put_user(record_count, (u32 __user *)arg);
		if (rc)
			return rc;
		return 0;
	default:
		return -ENOTTY;
	}
}

static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
			     size_t usize, loff_t *off)
{
	int rc;
	ssize_t len = 0;
	u64 id;

	if (*off != 0)
		return -EINVAL;

	if (mutex_lock_interruptible(&erst_dbg_mutex) != 0)
		return -EINTR;

retry_next:
	rc = erst_get_next_record_id(&id);
	if (rc)
		goto out;
	/* no more record */
	if (id == APEI_ERST_INVALID_RECORD_ID)
		goto out;
retry:
	rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
	/* The record may be cleared by others, try read next record */
	if (rc == -ENOENT)
		goto retry_next;
	if (rc < 0)
		goto out;
	if (len > ERST_DBG_RECORD_LEN_MAX) {
		pr_warning(ERST_DBG_PFX
			   "Record (ID: 0x%llx) length is too long: %zd\n",
			   id, len);
		rc = -EIO;
		goto out;
	}
	if (len > erst_dbg_buf_len) {
		kfree(erst_dbg_buf);
		rc = -ENOMEM;
		erst_dbg_buf = kmalloc(len, GFP_KERNEL);
		if (!erst_dbg_buf)
			goto out;
		erst_dbg_buf_len = len;
		goto retry;
	}

	rc = -EINVAL;
	if (len > usize)
		goto out;

	rc = -EFAULT;
	if (copy_to_user(ubuf, erst_dbg_buf, len))
		goto out;
	rc = 0;
out:
	mutex_unlock(&erst_dbg_mutex);
	return rc ? rc : len;
}

static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf,
			      size_t usize, loff_t *off)
{
	int rc;
	struct cper_record_header *rcd;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	if (usize > ERST_DBG_RECORD_LEN_MAX) {
		pr_err(ERST_DBG_PFX "Too long record to be written\n");
		return -EINVAL;
	}

	if (mutex_lock_interruptible(&erst_dbg_mutex))
		return -EINTR;
	if (usize > erst_dbg_buf_len) {
		kfree(erst_dbg_buf);
		rc = -ENOMEM;
		erst_dbg_buf = kmalloc(usize, GFP_KERNEL);
		if (!erst_dbg_buf)
			goto out;
		erst_dbg_buf_len = usize;
	}
	rc = copy_from_user(erst_dbg_buf, ubuf, usize);
	if (rc) {
		rc = -EFAULT;
		goto out;
	}
	rcd = erst_dbg_buf;
	rc = -EINVAL;
	if (rcd->record_length != usize)
		goto out;

	rc = erst_write(erst_dbg_buf);

out:
	mutex_unlock(&erst_dbg_mutex);
	return rc < 0 ? rc : usize;
}

static const struct file_operations erst_dbg_ops = {
	.owner		= THIS_MODULE,
	.open		= erst_dbg_open,
	.read		= erst_dbg_read,
	.write		= erst_dbg_write,
	.unlocked_ioctl	= erst_dbg_ioctl,
	.llseek		= no_llseek,
};

static struct miscdevice erst_dbg_dev = {
	.minor	= MISC_DYNAMIC_MINOR,
	.name	= "erst_dbg",
	.fops	= &erst_dbg_ops,
};

static __init int erst_dbg_init(void)
{
	return misc_register(&erst_dbg_dev);
}

static __exit void erst_dbg_exit(void)
{
	misc_deregister(&erst_dbg_dev);
	kfree(erst_dbg_buf);
}

module_init(erst_dbg_init);
module_exit(erst_dbg_exit);

MODULE_AUTHOR("Huang Ying");
MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support");
MODULE_LICENSE("GPL");
Commit	Line	Data
2ff729d5 HY	1	/*
	2	* APEI Error Record Serialization Table debug support
	3	*
	4	* ERST is a way provided by APEI to save and retrieve hardware error
	5	* infomation to and from a persistent store. This file provide the
	6	* debugging/testing support for ERST kernel support and firmware
	7	* implementation.
	8	*
	9	* Copyright 2010 Intel Corp.
	10	* Author: Huang Ying <ying.huang@intel.com>
	11	*
	12	* This program is free software; you can redistribute it and/or
	13	* modify it under the terms of the GNU General Public License version
	14	* 2 as published by the Free Software Foundation.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public License
	22	* along with this program; if not, write to the Free Software
	23	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	24	*/
	25
	26	#include <linux/kernel.h>
	27	#include <linux/module.h>
	28	#include <linux/uaccess.h>
	29	#include <acpi/apei.h>
	30	#include <linux/miscdevice.h>
	31
	32	#include "apei-internal.h"
	33
	34	#define ERST_DBG_PFX "ERST DBG: "
	35
	36	#define ERST_DBG_RECORD_LEN_MAX 4096
	37
	38	static void *erst_dbg_buf;
	39	static unsigned int erst_dbg_buf_len;
	40
	41	/* Prevent erst_dbg_read/write from being invoked concurrently */
	42	static DEFINE_MUTEX(erst_dbg_mutex);
	43
	44	static int erst_dbg_open(struct inode inode, struct file file)
	45	{
	46	if (erst_disable)
	47	return -ENODEV;
	48
	49	return nonseekable_open(inode, file);
	50	}
	51
	52	static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
	53	{
	54	int rc;
	55	u64 record_id;
	56	u32 record_count;
	57
	58	switch (cmd) {
	59	case APEI_ERST_CLEAR_RECORD:
	60	rc = copy_from_user(&record_id, (void __user *)arg,
	61	sizeof(record_id));
	62	if (rc)
	63	return -EFAULT;
	64	return erst_clear(record_id);
65	case APEI_ERST_GET_RECORD_COUNT:
66	rc = erst_get_record_count();
67	if (rc < 0)
68	return rc;
69	record_count = rc;
70	rc = put_user(record_count, (u32 __user *)arg);
71	if (rc)
72	return rc;
73	return 0;
74	default:
75	return -ENOTTY;
76	}
77	}
78
79	static ssize_t erst_dbg_read(struct file filp, char __user ubuf,
80	size_t usize, loff_t *off)
81	{
82	int rc;
83	ssize_t len = 0;
84	u64 id;
85
86	if (*off != 0)
87	return -EINVAL;
88
89	if (mutex_lock_interruptible(&erst_dbg_mutex) != 0)
90	return -EINTR;
91
92	retry_next:
93	rc = erst_get_next_record_id(&id);
94	if (rc)
95	goto out;
96	/* no more record */
97	if (id == APEI_ERST_INVALID_RECORD_ID)
98	goto out;
99	retry:
100	rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
101	/* The record may be cleared by others, try read next record */
102	if (rc == -ENOENT)
103	goto retry_next;
104	if (rc < 0)
105	goto out;
106	if (len > ERST_DBG_RECORD_LEN_MAX) {
107	pr_warning(ERST_DBG_PFX
108	"Record (ID: 0x%llx) length is too long: %zd\n",
109	id, len);
110	rc = -EIO;
111	goto out;
112	}
113	if (len > erst_dbg_buf_len) {
114	kfree(erst_dbg_buf);
115	rc = -ENOMEM;
116	erst_dbg_buf = kmalloc(len, GFP_KERNEL);
117	if (!erst_dbg_buf)
118	goto out;
119	erst_dbg_buf_len = len;
120	goto retry;
121	}
122
123	rc = -EINVAL;
124	if (len > usize)
125	goto out;
126
127	rc = -EFAULT;
128	if (copy_to_user(ubuf, erst_dbg_buf, len))
129	goto out;
130	rc = 0;
131	out:
132	mutex_unlock(&erst_dbg_mutex);
133	return rc ? rc : len;
134	}
135
136	static ssize_t erst_dbg_write(struct file filp, const char __user ubuf,
137	size_t usize, loff_t *off)
138	{
139	int rc;
140	struct cper_record_header *rcd;
141
142	if (!capable(CAP_SYS_ADMIN))
143	return -EPERM;
144
145	if (usize > ERST_DBG_RECORD_LEN_MAX) {
146	pr_err(ERST_DBG_PFX "Too long record to be written\n");
147	return -EINVAL;
148	}
149
150	if (mutex_lock_interruptible(&erst_dbg_mutex))
151	return -EINTR;
152	if (usize > erst_dbg_buf_len) {
153	kfree(erst_dbg_buf);
154	rc = -ENOMEM;
155	erst_dbg_buf = kmalloc(usize, GFP_KERNEL);
156	if (!erst_dbg_buf)
157	goto out;
158	erst_dbg_buf_len = usize;
159	}
160	rc = copy_from_user(erst_dbg_buf, ubuf, usize);
161	if (rc) {
162	rc = -EFAULT;
163	goto out;
164	}
165	rcd = erst_dbg_buf;
166	rc = -EINVAL;
167	if (rcd->record_length != usize)
168	goto out;
169
170	rc = erst_write(erst_dbg_buf);
171
172	out:
173	mutex_unlock(&erst_dbg_mutex);
174	return rc < 0 ? rc : usize;
175	}
176
177	static const struct file_operations erst_dbg_ops = {
178	.owner = THIS_MODULE,
179	.open = erst_dbg_open,
180	.read = erst_dbg_read,
181	.write = erst_dbg_write,
182	.unlocked_ioctl = erst_dbg_ioctl,
6038f373	183	.llseek = no_llseek,
2ff729d5 HY	184	};
	185
	186	static struct miscdevice erst_dbg_dev = {
	187	.minor = MISC_DYNAMIC_MINOR,
	188	.name = "erst_dbg",
	189	.fops = &erst_dbg_ops,
	190	};
	191
	192	static __init int erst_dbg_init(void)
	193	{
	194	return misc_register(&erst_dbg_dev);
	195	}
	196
	197	static __exit void erst_dbg_exit(void)
	198	{
	199	misc_deregister(&erst_dbg_dev);
	200	kfree(erst_dbg_buf);
	201	}
	202
	203	module_init(erst_dbg_init);
	204	module_exit(erst_dbg_exit);
	205
	206	MODULE_AUTHOR("Huang Ying");
	207	MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support");
	208	MODULE_LICENSE("GPL");