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 (mtd_can_have_bb(mtd)) { 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 (mtd_can_have_bb(mtd) && ret == -EIO) { 203 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size); 204 if (ret < 0) { 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_can_have_bb(mtd) && 261 mtd_block_isbad(mtd, page * record_size)) 262 continue; 263 /* Assume the page is used */ 264 mark_page_used(cxt, page); 265 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, 266 &retlen, (u_char *)&count[0]); 267 if (retlen != MTDOOPS_HEADER_SIZE || 268 (ret < 0 && !mtd_is_bitflip(ret))) { 269 printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", 270 page * record_size, retlen, 271 MTDOOPS_HEADER_SIZE, ret); 272 continue; 273 } 274 275 if (count[0] == 0xffffffff && count[1] == 0xffffffff) 276 mark_page_unused(cxt, page); 277 if (count[0] == 0xffffffff) 278 continue; 279 if (maxcount == 0xffffffff) { 280 maxcount = count[0]; 281 maxpos = page; 282 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) { 283 maxcount = count[0]; 284 maxpos = page; 285 } else if (count[0] > maxcount && count[0] < 0xc0000000) { 286 maxcount = count[0]; 287 maxpos = page; 288 } else if (count[0] > maxcount && count[0] > 0xc0000000 289 && maxcount > 0x80000000) { 290 maxcount = count[0]; 291 maxpos = page; 292 } 293 } 294 if (maxcount == 0xffffffff) { 295 cxt->nextpage = 0; 296 cxt->nextcount = 1; 297 schedule_work(&cxt->work_erase); 298 return; 299 } 300 301 cxt->nextpage = maxpos; 302 cxt->nextcount = maxcount; 303 304 mtdoops_inc_counter(cxt); 305 } 306 307 static void mtdoops_do_dump(struct kmsg_dumper *dumper, 308 enum kmsg_dump_reason reason, const char *s1, unsigned long l1, 309 const char *s2, unsigned long l2) 310 { 311 struct mtdoops_context *cxt = container_of(dumper, 312 struct mtdoops_context, dump); 313 unsigned long s1_start, s2_start; 314 unsigned long l1_cpy, l2_cpy; 315 char *dst; 316 317 if (reason != KMSG_DUMP_OOPS && 318 reason != KMSG_DUMP_PANIC) 319 return; 320 321 /* Only dump oopses if dump_oops is set */ 322 if (reason == KMSG_DUMP_OOPS && !dump_oops) 323 return; 324 325 dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */ 326 l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE); 327 l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy); 328 329 s2_start = l2 - l2_cpy; 330 s1_start = l1 - l1_cpy; 331 332 memcpy(dst, s1 + s1_start, l1_cpy); 333 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); 334 335 /* Panics must be written immediately */ 336 if (reason != KMSG_DUMP_OOPS) 337 mtdoops_write(cxt, 1); 338 339 /* For other cases, schedule work to write it "nicely" */ 340 schedule_work(&cxt->work_write); 341 } 342 343 static void mtdoops_notify_add(struct mtd_info *mtd) 344 { 345 struct mtdoops_context *cxt = &oops_cxt; 346 u64 mtdoops_pages = div_u64(mtd->size, record_size); 347 int err; 348 349 if (!strcmp(mtd->name, mtddev)) 350 cxt->mtd_index = mtd->index; 351 352 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 353 return; 354 355 if (mtd->size < mtd->erasesize * 2) { 356 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", 357 mtd->index); 358 return; 359 } 360 if (mtd->erasesize < record_size) { 361 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", 362 mtd->index); 363 return; 364 } 365 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { 366 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n", 367 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024); 368 return; 369 } 370 371 /* oops_page_used is a bit field */ 372 cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages, 373 BITS_PER_LONG) * sizeof(unsigned long)); 374 if (!cxt->oops_page_used) { 375 printk(KERN_ERR "mtdoops: could not allocate page array\n"); 376 return; 377 } 378 379 cxt->dump.dump = mtdoops_do_dump; 380 err = kmsg_dump_register(&cxt->dump); 381 if (err) { 382 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err); 383 vfree(cxt->oops_page_used); 384 cxt->oops_page_used = NULL; 385 return; 386 } 387 388 cxt->mtd = mtd; 389 cxt->oops_pages = (int)mtd->size / record_size; 390 find_next_position(cxt); 391 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 392 } 393 394 static void mtdoops_notify_remove(struct mtd_info *mtd) 395 { 396 struct mtdoops_context *cxt = &oops_cxt; 397 398 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 399 return; 400 401 if (kmsg_dump_unregister(&cxt->dump) < 0) 402 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n"); 403 404 cxt->mtd = NULL; 405 flush_work_sync(&cxt->work_erase); 406 flush_work_sync(&cxt->work_write); 407 } 408 409 410 static struct mtd_notifier mtdoops_notifier = { 411 .add = mtdoops_notify_add, 412 .remove = mtdoops_notify_remove, 413 }; 414 415 static int __init mtdoops_init(void) 416 { 417 struct mtdoops_context *cxt = &oops_cxt; 418 int mtd_index; 419 char *endp; 420 421 if (strlen(mtddev) == 0) { 422 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); 423 return -EINVAL; 424 } 425 if ((record_size & 4095) != 0) { 426 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); 427 return -EINVAL; 428 } 429 if (record_size < 4096) { 430 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); 431 return -EINVAL; 432 } 433 434 /* Setup the MTD device to use */ 435 cxt->mtd_index = -1; 436 mtd_index = simple_strtoul(mtddev, &endp, 0); 437 if (*endp == '\0') 438 cxt->mtd_index = mtd_index; 439 440 cxt->oops_buf = vmalloc(record_size); 441 if (!cxt->oops_buf) { 442 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); 443 return -ENOMEM; 444 } 445 memset(cxt->oops_buf, 0xff, record_size); 446 447 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 448 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 449 450 register_mtd_user(&mtdoops_notifier); 451 return 0; 452 } 453 454 static void __exit mtdoops_exit(void) 455 { 456 struct mtdoops_context *cxt = &oops_cxt; 457 458 unregister_mtd_user(&mtdoops_notifier); 459 vfree(cxt->oops_buf); 460 vfree(cxt->oops_page_used); 461 } 462 463 464 module_init(mtdoops_init); 465 module_exit(mtdoops_exit); 466 467 MODULE_LICENSE("GPL"); 468 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 469 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 470