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 void mtdoops_erase_callback(struct erase_info *done) 88 { 89 wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv; 90 wake_up(wait_q); 91 } 92 93 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset) 94 { 95 struct mtd_info *mtd = cxt->mtd; 96 u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize; 97 u32 start_page = start_page_offset / record_size; 98 u32 erase_pages = mtd->erasesize / record_size; 99 struct erase_info erase; 100 DECLARE_WAITQUEUE(wait, current); 101 wait_queue_head_t wait_q; 102 int ret; 103 int page; 104 105 init_waitqueue_head(&wait_q); 106 erase.mtd = mtd; 107 erase.callback = mtdoops_erase_callback; 108 erase.addr = offset; 109 erase.len = mtd->erasesize; 110 erase.priv = (u_long)&wait_q; 111 112 set_current_state(TASK_INTERRUPTIBLE); 113 add_wait_queue(&wait_q, &wait); 114 115 ret = mtd_erase(mtd, &erase); 116 if (ret) { 117 set_current_state(TASK_RUNNING); 118 remove_wait_queue(&wait_q, &wait); 119 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", 120 (unsigned long long)erase.addr, 121 (unsigned long long)erase.len, mtddev); 122 return ret; 123 } 124 125 schedule(); /* Wait for erase to finish. */ 126 remove_wait_queue(&wait_q, &wait); 127 128 /* Mark pages as unused */ 129 for (page = start_page; page < start_page + erase_pages; page++) 130 mark_page_unused(cxt, page); 131 132 return 0; 133 } 134 135 static void mtdoops_inc_counter(struct mtdoops_context *cxt) 136 { 137 cxt->nextpage++; 138 if (cxt->nextpage >= cxt->oops_pages) 139 cxt->nextpage = 0; 140 cxt->nextcount++; 141 if (cxt->nextcount == 0xffffffff) 142 cxt->nextcount = 0; 143 144 if (page_is_used(cxt, cxt->nextpage)) { 145 schedule_work(&cxt->work_erase); 146 return; 147 } 148 149 printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", 150 cxt->nextpage, cxt->nextcount); 151 } 152 153 /* Scheduled work - when we can't proceed without erasing a block */ 154 static void mtdoops_workfunc_erase(struct work_struct *work) 155 { 156 struct mtdoops_context *cxt = 157 container_of(work, struct mtdoops_context, work_erase); 158 struct mtd_info *mtd = cxt->mtd; 159 int i = 0, j, ret, mod; 160 161 /* We were unregistered */ 162 if (!mtd) 163 return; 164 165 mod = (cxt->nextpage * record_size) % mtd->erasesize; 166 if (mod != 0) { 167 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size); 168 if (cxt->nextpage >= cxt->oops_pages) 169 cxt->nextpage = 0; 170 } 171 172 while (1) { 173 ret = mtd_block_isbad(mtd, cxt->nextpage * record_size); 174 if (!ret) 175 break; 176 if (ret < 0) { 177 printk(KERN_ERR "mtdoops: block_isbad failed, aborting\n"); 178 return; 179 } 180 badblock: 181 printk(KERN_WARNING "mtdoops: bad block at %08lx\n", 182 cxt->nextpage * record_size); 183 i++; 184 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size); 185 if (cxt->nextpage >= cxt->oops_pages) 186 cxt->nextpage = 0; 187 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) { 188 printk(KERN_ERR "mtdoops: all blocks bad!\n"); 189 return; 190 } 191 } 192 193 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) 194 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size); 195 196 if (ret >= 0) { 197 printk(KERN_DEBUG "mtdoops: ready %d, %d\n", 198 cxt->nextpage, cxt->nextcount); 199 return; 200 } 201 202 if (ret == -EIO) { 203 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size); 204 if (ret < 0 && ret != -EOPNOTSUPP) { 205 printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n"); 206 return; 207 } 208 } 209 goto badblock; 210 } 211 212 static void mtdoops_write(struct mtdoops_context *cxt, int panic) 213 { 214 struct mtd_info *mtd = cxt->mtd; 215 size_t retlen; 216 u32 *hdr; 217 int ret; 218 219 /* Add mtdoops header to the buffer */ 220 hdr = cxt->oops_buf; 221 hdr[0] = cxt->nextcount; 222 hdr[1] = MTDOOPS_KERNMSG_MAGIC; 223 224 if (panic) { 225 ret = mtd_panic_write(mtd, cxt->nextpage * record_size, 226 record_size, &retlen, cxt->oops_buf); 227 if (ret == -EOPNOTSUPP) { 228 printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); 229 return; 230 } 231 } else 232 ret = mtd_write(mtd, cxt->nextpage * record_size, 233 record_size, &retlen, cxt->oops_buf); 234 235 if (retlen != record_size || ret < 0) 236 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", 237 cxt->nextpage * record_size, retlen, record_size, ret); 238 mark_page_used(cxt, cxt->nextpage); 239 memset(cxt->oops_buf, 0xff, record_size); 240 241 mtdoops_inc_counter(cxt); 242 } 243 244 static void mtdoops_workfunc_write(struct work_struct *work) 245 { 246 struct mtdoops_context *cxt = 247 container_of(work, struct mtdoops_context, work_write); 248 249 mtdoops_write(cxt, 0); 250 } 251 252 static void find_next_position(struct mtdoops_context *cxt) 253 { 254 struct mtd_info *mtd = cxt->mtd; 255 int ret, page, maxpos = 0; 256 u32 count[2], maxcount = 0xffffffff; 257 size_t retlen; 258 259 for (page = 0; page < cxt->oops_pages; page++) { 260 if (mtd_block_isbad(mtd, page * record_size)) 261 continue; 262 /* Assume the page is used */ 263 mark_page_used(cxt, page); 264 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, 265 &retlen, (u_char *)&count[0]); 266 if (retlen != MTDOOPS_HEADER_SIZE || 267 (ret < 0 && !mtd_is_bitflip(ret))) { 268 printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", 269 page * record_size, retlen, 270 MTDOOPS_HEADER_SIZE, ret); 271 continue; 272 } 273 274 if (count[0] == 0xffffffff && count[1] == 0xffffffff) 275 mark_page_unused(cxt, page); 276 if (count[0] == 0xffffffff) 277 continue; 278 if (maxcount == 0xffffffff) { 279 maxcount = count[0]; 280 maxpos = page; 281 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) { 282 maxcount = count[0]; 283 maxpos = page; 284 } else if (count[0] > maxcount && count[0] < 0xc0000000) { 285 maxcount = count[0]; 286 maxpos = page; 287 } else if (count[0] > maxcount && count[0] > 0xc0000000 288 && maxcount > 0x80000000) { 289 maxcount = count[0]; 290 maxpos = page; 291 } 292 } 293 if (maxcount == 0xffffffff) { 294 cxt->nextpage = 0; 295 cxt->nextcount = 1; 296 schedule_work(&cxt->work_erase); 297 return; 298 } 299 300 cxt->nextpage = maxpos; 301 cxt->nextcount = maxcount; 302 303 mtdoops_inc_counter(cxt); 304 } 305 306 static void mtdoops_do_dump(struct kmsg_dumper *dumper, 307 enum kmsg_dump_reason reason, const char *s1, unsigned long l1, 308 const char *s2, unsigned long l2) 309 { 310 struct mtdoops_context *cxt = container_of(dumper, 311 struct mtdoops_context, dump); 312 unsigned long s1_start, s2_start; 313 unsigned long l1_cpy, l2_cpy; 314 char *dst; 315 316 if (reason != KMSG_DUMP_OOPS && 317 reason != KMSG_DUMP_PANIC) 318 return; 319 320 /* Only dump oopses if dump_oops is set */ 321 if (reason == KMSG_DUMP_OOPS && !dump_oops) 322 return; 323 324 dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */ 325 l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE); 326 l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy); 327 328 s2_start = l2 - l2_cpy; 329 s1_start = l1 - l1_cpy; 330 331 memcpy(dst, s1 + s1_start, l1_cpy); 332 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); 333 334 /* Panics must be written immediately */ 335 if (reason != KMSG_DUMP_OOPS) 336 mtdoops_write(cxt, 1); 337 338 /* For other cases, schedule work to write it "nicely" */ 339 schedule_work(&cxt->work_write); 340 } 341 342 static void mtdoops_notify_add(struct mtd_info *mtd) 343 { 344 struct mtdoops_context *cxt = &oops_cxt; 345 u64 mtdoops_pages = div_u64(mtd->size, record_size); 346 int err; 347 348 if (!strcmp(mtd->name, mtddev)) 349 cxt->mtd_index = mtd->index; 350 351 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 352 return; 353 354 if (mtd->size < mtd->erasesize * 2) { 355 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", 356 mtd->index); 357 return; 358 } 359 if (mtd->erasesize < record_size) { 360 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", 361 mtd->index); 362 return; 363 } 364 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { 365 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n", 366 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024); 367 return; 368 } 369 370 /* oops_page_used is a bit field */ 371 cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages, 372 BITS_PER_LONG) * sizeof(unsigned long)); 373 if (!cxt->oops_page_used) { 374 printk(KERN_ERR "mtdoops: could not allocate page array\n"); 375 return; 376 } 377 378 cxt->dump.dump = mtdoops_do_dump; 379 err = kmsg_dump_register(&cxt->dump); 380 if (err) { 381 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err); 382 vfree(cxt->oops_page_used); 383 cxt->oops_page_used = NULL; 384 return; 385 } 386 387 cxt->mtd = mtd; 388 cxt->oops_pages = (int)mtd->size / record_size; 389 find_next_position(cxt); 390 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 391 } 392 393 static void mtdoops_notify_remove(struct mtd_info *mtd) 394 { 395 struct mtdoops_context *cxt = &oops_cxt; 396 397 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 398 return; 399 400 if (kmsg_dump_unregister(&cxt->dump) < 0) 401 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n"); 402 403 cxt->mtd = NULL; 404 flush_work_sync(&cxt->work_erase); 405 flush_work_sync(&cxt->work_write); 406 } 407 408 409 static struct mtd_notifier mtdoops_notifier = { 410 .add = mtdoops_notify_add, 411 .remove = mtdoops_notify_remove, 412 }; 413 414 static int __init mtdoops_init(void) 415 { 416 struct mtdoops_context *cxt = &oops_cxt; 417 int mtd_index; 418 char *endp; 419 420 if (strlen(mtddev) == 0) { 421 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); 422 return -EINVAL; 423 } 424 if ((record_size & 4095) != 0) { 425 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); 426 return -EINVAL; 427 } 428 if (record_size < 4096) { 429 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); 430 return -EINVAL; 431 } 432 433 /* Setup the MTD device to use */ 434 cxt->mtd_index = -1; 435 mtd_index = simple_strtoul(mtddev, &endp, 0); 436 if (*endp == '\0') 437 cxt->mtd_index = mtd_index; 438 439 cxt->oops_buf = vmalloc(record_size); 440 if (!cxt->oops_buf) { 441 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); 442 return -ENOMEM; 443 } 444 memset(cxt->oops_buf, 0xff, record_size); 445 446 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 447 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 448 449 register_mtd_user(&mtdoops_notifier); 450 return 0; 451 } 452 453 static void __exit mtdoops_exit(void) 454 { 455 struct mtdoops_context *cxt = &oops_cxt; 456 457 unregister_mtd_user(&mtdoops_notifier); 458 vfree(cxt->oops_buf); 459 vfree(cxt->oops_page_used); 460 } 461 462 463 module_init(mtdoops_init); 464 module_exit(mtdoops_exit); 465 466 MODULE_LICENSE("GPL"); 467 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 468 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 469