Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 1 | /* |
| 2 | * APEI Error Record Serialization Table debug support |
| 3 | * |
| 4 | * ERST is a way provided by APEI to save and retrieve hardware error |
Lucas De Marchi | 58f87ed | 2010-09-07 12:49:45 -0400 | [diff] [blame] | 5 | * information to and from a persistent store. This file provide the |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 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) { |
Huang Ying | 23f124c | 2010-09-29 19:53:54 +0800 | [diff] [blame] | 114 | void *p; |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 115 | rc = -ENOMEM; |
Huang Ying | 23f124c | 2010-09-29 19:53:54 +0800 | [diff] [blame] | 116 | p = kmalloc(len, GFP_KERNEL); |
| 117 | if (!p) |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 118 | goto out; |
Huang Ying | 23f124c | 2010-09-29 19:53:54 +0800 | [diff] [blame] | 119 | kfree(erst_dbg_buf); |
| 120 | erst_dbg_buf = p; |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 121 | erst_dbg_buf_len = len; |
| 122 | goto retry; |
| 123 | } |
| 124 | |
| 125 | rc = -EINVAL; |
| 126 | if (len > usize) |
| 127 | goto out; |
| 128 | |
| 129 | rc = -EFAULT; |
| 130 | if (copy_to_user(ubuf, erst_dbg_buf, len)) |
| 131 | goto out; |
| 132 | rc = 0; |
| 133 | out: |
| 134 | mutex_unlock(&erst_dbg_mutex); |
| 135 | return rc ? rc : len; |
| 136 | } |
| 137 | |
| 138 | static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf, |
| 139 | size_t usize, loff_t *off) |
| 140 | { |
| 141 | int rc; |
| 142 | struct cper_record_header *rcd; |
| 143 | |
| 144 | if (!capable(CAP_SYS_ADMIN)) |
| 145 | return -EPERM; |
| 146 | |
| 147 | if (usize > ERST_DBG_RECORD_LEN_MAX) { |
| 148 | pr_err(ERST_DBG_PFX "Too long record to be written\n"); |
| 149 | return -EINVAL; |
| 150 | } |
| 151 | |
| 152 | if (mutex_lock_interruptible(&erst_dbg_mutex)) |
| 153 | return -EINTR; |
| 154 | if (usize > erst_dbg_buf_len) { |
Huang Ying | 23f124c | 2010-09-29 19:53:54 +0800 | [diff] [blame] | 155 | void *p; |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 156 | rc = -ENOMEM; |
Huang Ying | 23f124c | 2010-09-29 19:53:54 +0800 | [diff] [blame] | 157 | p = kmalloc(usize, GFP_KERNEL); |
| 158 | if (!p) |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 159 | goto out; |
Huang Ying | 23f124c | 2010-09-29 19:53:54 +0800 | [diff] [blame] | 160 | kfree(erst_dbg_buf); |
| 161 | erst_dbg_buf = p; |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 162 | erst_dbg_buf_len = usize; |
| 163 | } |
| 164 | rc = copy_from_user(erst_dbg_buf, ubuf, usize); |
| 165 | if (rc) { |
| 166 | rc = -EFAULT; |
| 167 | goto out; |
| 168 | } |
| 169 | rcd = erst_dbg_buf; |
| 170 | rc = -EINVAL; |
| 171 | if (rcd->record_length != usize) |
| 172 | goto out; |
| 173 | |
| 174 | rc = erst_write(erst_dbg_buf); |
| 175 | |
| 176 | out: |
| 177 | mutex_unlock(&erst_dbg_mutex); |
| 178 | return rc < 0 ? rc : usize; |
| 179 | } |
| 180 | |
| 181 | static const struct file_operations erst_dbg_ops = { |
| 182 | .owner = THIS_MODULE, |
| 183 | .open = erst_dbg_open, |
| 184 | .read = erst_dbg_read, |
| 185 | .write = erst_dbg_write, |
| 186 | .unlocked_ioctl = erst_dbg_ioctl, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 187 | .llseek = no_llseek, |
Huang Ying | 2ff729d | 2010-08-12 11:55:17 +0800 | [diff] [blame] | 188 | }; |
| 189 | |
| 190 | static struct miscdevice erst_dbg_dev = { |
| 191 | .minor = MISC_DYNAMIC_MINOR, |
| 192 | .name = "erst_dbg", |
| 193 | .fops = &erst_dbg_ops, |
| 194 | }; |
| 195 | |
| 196 | static __init int erst_dbg_init(void) |
| 197 | { |
| 198 | return misc_register(&erst_dbg_dev); |
| 199 | } |
| 200 | |
| 201 | static __exit void erst_dbg_exit(void) |
| 202 | { |
| 203 | misc_deregister(&erst_dbg_dev); |
| 204 | kfree(erst_dbg_buf); |
| 205 | } |
| 206 | |
| 207 | module_init(erst_dbg_init); |
| 208 | module_exit(erst_dbg_exit); |
| 209 | |
| 210 | MODULE_AUTHOR("Huang Ying"); |
| 211 | MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support"); |
| 212 | MODULE_LICENSE("GPL"); |