1 /* 2 * MTD Oops/Panic logger 3 * 4 * Copyright © 2007 Nokia Corporation. All rights reserved. 5 * 6 * Author: Richard Purdie <rpurdie@openedhand.com> 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License 10 * version 2 as published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope that it will be useful, but 13 * WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 20 * 02110-1301 USA 21 * 22 */ 23 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/console.h> 27 #include <linux/vmalloc.h> 28 #include <linux/workqueue.h> 29 #include <linux/sched.h> 30 #include <linux/wait.h> 31 #include <linux/delay.h> 32 #include <linux/interrupt.h> 33 #include <linux/mtd/mtd.h> 34 #include <linux/kmsg_dump.h> 35 36 /* Maximum MTD partition size */ 37 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024) 38 39 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00 40 #define MTDOOPS_HEADER_SIZE 8 41 42 static unsigned long record_size = 4096; 43 module_param(record_size, ulong, 0400); 44 MODULE_PARM_DESC(record_size, 45 "record size for MTD OOPS pages in bytes (default 4096)"); 46 47 static char mtddev[80]; 48 module_param_string(mtddev, mtddev, 80, 0400); 49 MODULE_PARM_DESC(mtddev, 50 "name or index number of the MTD device to use"); 51 52 static int dump_oops = 1; 53 module_param(dump_oops, int, 0600); 54 MODULE_PARM_DESC(dump_oops, 55 "set to 1 to dump oopses, 0 to only dump panics (default 1)"); 56 57 static struct mtdoops_context { 58 struct kmsg_dumper dump; 59 60 int mtd_index; 61 struct work_struct work_erase; 62 struct work_struct work_write; 63 struct mtd_info *mtd; 64 int oops_pages; 65 int nextpage; 66 int nextcount; 67 unsigned long *oops_page_used; 68 69 void *oops_buf; 70 } oops_cxt; 71 72 static void mark_page_used(struct mtdoops_context *cxt, int page) 73 { 74 set_bit(page, cxt->oops_page_used); 75 } 76 77 static void mark_page_unused(struct mtdoops_context *cxt, int page) 78 { 79 clear_bit(page, cxt->oops_page_used); 80 } 81 82 static int page_is_used(struct mtdoops_context *cxt, int page) 83 { 84 return test_bit(page, cxt->oops_page_used); 85 } 86 87 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset) 88 { 89 struct mtd_info *mtd = cxt->mtd; 90 u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize; 91 u32 start_page = start_page_offset / record_size; 92 u32 erase_pages = mtd->erasesize / record_size; 93 struct erase_info erase; 94 int ret; 95 int page; 96 97 erase.addr = offset; 98 erase.len = mtd->erasesize; 99 100 ret = mtd_erase(mtd, &erase); 101 if (ret) { 102 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", 103 (unsigned long long)erase.addr, 104 (unsigned long long)erase.len, mtddev); 105 return ret; 106 } 107 108 /* Mark pages as unused */ 109 for (page = start_page; page < start_page + erase_pages; page++) 110 mark_page_unused(cxt, page); 111 112 return 0; 113 } 114 115 static void mtdoops_inc_counter(struct mtdoops_context *cxt) 116 { 117 cxt->nextpage++; 118 if (cxt->nextpage >= cxt->oops_pages) 119 cxt->nextpage = 0; 120 cxt->nextcount++; 121 if (cxt->nextcount == 0xffffffff) 122 cxt->nextcount = 0; 123 124 if (page_is_used(cxt, cxt->nextpage)) { 125 schedule_work(&cxt->work_erase); 126 return; 127 } 128 129 printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", 130 cxt->nextpage, cxt->nextcount); 131 } 132 133 /* Scheduled work - when we can't proceed without erasing a block */ 134 static void mtdoops_workfunc_erase(struct work_struct *work) 135 { 136 struct mtdoops_context *cxt = 137 container_of(work, struct mtdoops_context, work_erase); 138 struct mtd_info *mtd = cxt->mtd; 139 int i = 0, j, ret, mod; 140 141 /* We were unregistered */ 142 if (!mtd) 143 return; 144 145 mod = (cxt->nextpage * record_size) % mtd->erasesize; 146 if (mod != 0) { 147 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size); 148 if (cxt->nextpage >= cxt->oops_pages) 149 cxt->nextpage = 0; 150 } 151 152 while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) { 153 badblock: 154 printk(KERN_WARNING "mtdoops: bad block at %08lx\n", 155 cxt->nextpage * record_size); 156 i++; 157 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size); 158 if (cxt->nextpage >= cxt->oops_pages) 159 cxt->nextpage = 0; 160 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) { 161 printk(KERN_ERR "mtdoops: all blocks bad!\n"); 162 return; 163 } 164 } 165 166 if (ret < 0) { 167 printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n"); 168 return; 169 } 170 171 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) 172 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size); 173 174 if (ret >= 0) { 175 printk(KERN_DEBUG "mtdoops: ready %d, %d\n", 176 cxt->nextpage, cxt->nextcount); 177 return; 178 } 179 180 if (ret == -EIO) { 181 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size); 182 if (ret < 0 && ret != -EOPNOTSUPP) { 183 printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n"); 184 return; 185 } 186 } 187 goto badblock; 188 } 189 190 static void mtdoops_write(struct mtdoops_context *cxt, int panic) 191 { 192 struct mtd_info *mtd = cxt->mtd; 193 size_t retlen; 194 u32 *hdr; 195 int ret; 196 197 /* Add mtdoops header to the buffer */ 198 hdr = cxt->oops_buf; 199 hdr[0] = cxt->nextcount; 200 hdr[1] = MTDOOPS_KERNMSG_MAGIC; 201 202 if (panic) { 203 ret = mtd_panic_write(mtd, cxt->nextpage * record_size, 204 record_size, &retlen, cxt->oops_buf); 205 if (ret == -EOPNOTSUPP) { 206 printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); 207 return; 208 } 209 } else 210 ret = mtd_write(mtd, cxt->nextpage * record_size, 211 record_size, &retlen, cxt->oops_buf); 212 213 if (retlen != record_size || ret < 0) 214 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", 215 cxt->nextpage * record_size, retlen, record_size, ret); 216 mark_page_used(cxt, cxt->nextpage); 217 memset(cxt->oops_buf, 0xff, record_size); 218 219 mtdoops_inc_counter(cxt); 220 } 221 222 static void mtdoops_workfunc_write(struct work_struct *work) 223 { 224 struct mtdoops_context *cxt = 225 container_of(work, struct mtdoops_context, work_write); 226 227 mtdoops_write(cxt, 0); 228 } 229 230 static void find_next_position(struct mtdoops_context *cxt) 231 { 232 struct mtd_info *mtd = cxt->mtd; 233 int ret, page, maxpos = 0; 234 u32 count[2], maxcount = 0xffffffff; 235 size_t retlen; 236 237 for (page = 0; page < cxt->oops_pages; page++) { 238 if (mtd_block_isbad(mtd, page * record_size)) 239 continue; 240 /* Assume the page is used */ 241 mark_page_used(cxt, page); 242 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, 243 &retlen, (u_char *)&count[0]); 244 if (retlen != MTDOOPS_HEADER_SIZE || 245 (ret < 0 && !mtd_is_bitflip(ret))) { 246 printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", 247 page * record_size, retlen, 248 MTDOOPS_HEADER_SIZE, ret); 249 continue; 250 } 251 252 if (count[0] == 0xffffffff && count[1] == 0xffffffff) 253 mark_page_unused(cxt, page); 254 if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC) 255 continue; 256 if (maxcount == 0xffffffff) { 257 maxcount = count[0]; 258 maxpos = page; 259 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) { 260 maxcount = count[0]; 261 maxpos = page; 262 } else if (count[0] > maxcount && count[0] < 0xc0000000) { 263 maxcount = count[0]; 264 maxpos = page; 265 } else if (count[0] > maxcount && count[0] > 0xc0000000 266 && maxcount > 0x80000000) { 267 maxcount = count[0]; 268 maxpos = page; 269 } 270 } 271 if (maxcount == 0xffffffff) { 272 cxt->nextpage = cxt->oops_pages - 1; 273 cxt->nextcount = 0; 274 } 275 else { 276 cxt->nextpage = maxpos; 277 cxt->nextcount = maxcount; 278 } 279 280 mtdoops_inc_counter(cxt); 281 } 282 283 static void mtdoops_do_dump(struct kmsg_dumper *dumper, 284 enum kmsg_dump_reason reason) 285 { 286 struct mtdoops_context *cxt = container_of(dumper, 287 struct mtdoops_context, dump); 288 289 /* Only dump oopses if dump_oops is set */ 290 if (reason == KMSG_DUMP_OOPS && !dump_oops) 291 return; 292 293 kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, 294 record_size - MTDOOPS_HEADER_SIZE, NULL); 295 296 /* Panics must be written immediately */ 297 if (reason != KMSG_DUMP_OOPS) 298 mtdoops_write(cxt, 1); 299 300 /* For other cases, schedule work to write it "nicely" */ 301 schedule_work(&cxt->work_write); 302 } 303 304 static void mtdoops_notify_add(struct mtd_info *mtd) 305 { 306 struct mtdoops_context *cxt = &oops_cxt; 307 u64 mtdoops_pages = div_u64(mtd->size, record_size); 308 int err; 309 310 if (!strcmp(mtd->name, mtddev)) 311 cxt->mtd_index = mtd->index; 312 313 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 314 return; 315 316 if (mtd->size < mtd->erasesize * 2) { 317 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", 318 mtd->index); 319 return; 320 } 321 if (mtd->erasesize < record_size) { 322 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", 323 mtd->index); 324 return; 325 } 326 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { 327 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n", 328 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024); 329 return; 330 } 331 332 /* oops_page_used is a bit field */ 333 cxt->oops_page_used = 334 vmalloc(array_size(sizeof(unsigned long), 335 DIV_ROUND_UP(mtdoops_pages, 336 BITS_PER_LONG))); 337 if (!cxt->oops_page_used) { 338 printk(KERN_ERR "mtdoops: could not allocate page array\n"); 339 return; 340 } 341 342 cxt->dump.max_reason = KMSG_DUMP_OOPS; 343 cxt->dump.dump = mtdoops_do_dump; 344 err = kmsg_dump_register(&cxt->dump); 345 if (err) { 346 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err); 347 vfree(cxt->oops_page_used); 348 cxt->oops_page_used = NULL; 349 return; 350 } 351 352 cxt->mtd = mtd; 353 cxt->oops_pages = (int)mtd->size / record_size; 354 find_next_position(cxt); 355 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 356 } 357 358 static void mtdoops_notify_remove(struct mtd_info *mtd) 359 { 360 struct mtdoops_context *cxt = &oops_cxt; 361 362 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 363 return; 364 365 if (kmsg_dump_unregister(&cxt->dump) < 0) 366 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n"); 367 368 cxt->mtd = NULL; 369 flush_work(&cxt->work_erase); 370 flush_work(&cxt->work_write); 371 } 372 373 374 static struct mtd_notifier mtdoops_notifier = { 375 .add = mtdoops_notify_add, 376 .remove = mtdoops_notify_remove, 377 }; 378 379 static int __init mtdoops_init(void) 380 { 381 struct mtdoops_context *cxt = &oops_cxt; 382 int mtd_index; 383 char *endp; 384 385 if (strlen(mtddev) == 0) { 386 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); 387 return -EINVAL; 388 } 389 if ((record_size & 4095) != 0) { 390 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); 391 return -EINVAL; 392 } 393 if (record_size < 4096) { 394 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); 395 return -EINVAL; 396 } 397 398 /* Setup the MTD device to use */ 399 cxt->mtd_index = -1; 400 mtd_index = simple_strtoul(mtddev, &endp, 0); 401 if (*endp == '\0') 402 cxt->mtd_index = mtd_index; 403 404 cxt->oops_buf = vmalloc(record_size); 405 if (!cxt->oops_buf) { 406 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); 407 return -ENOMEM; 408 } 409 memset(cxt->oops_buf, 0xff, record_size); 410 411 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 412 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 413 414 register_mtd_user(&mtdoops_notifier); 415 return 0; 416 } 417 418 static void __exit mtdoops_exit(void) 419 { 420 struct mtdoops_context *cxt = &oops_cxt; 421 422 unregister_mtd_user(&mtdoops_notifier); 423 vfree(cxt->oops_buf); 424 vfree(cxt->oops_page_used); 425 } 426 427 428 module_init(mtdoops_init); 429 module_exit(mtdoops_exit); 430 431 MODULE_LICENSE("GPL"); 432 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 433 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 434