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 42static unsigned long record_size = 4096; 43module_param(record_size, ulong, 0400); 44MODULE_PARM_DESC(record_size, 45 "record size for MTD OOPS pages in bytes (default 4096)"); 46 47static char mtddev[80]; 48module_param_string(mtddev, mtddev, 80, 0400); 49MODULE_PARM_DESC(mtddev, 50 "name or index number of the MTD device to use"); 51 52static int dump_oops = 1; 53module_param(dump_oops, int, 0600); 54MODULE_PARM_DESC(dump_oops, 55 "set to 1 to dump oopses, 0 to only dump panics (default 1)"); 56 57static 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 72static void mark_page_used(struct mtdoops_context *cxt, int page) 73{ 74 set_bit(page, cxt->oops_page_used); 75} 76 77static void mark_page_unused(struct mtdoops_context *cxt, int page) 78{ 79 clear_bit(page, cxt->oops_page_used); 80} 81 82static int page_is_used(struct mtdoops_context *cxt, int page) 83{ 84 return test_bit(page, cxt->oops_page_used); 85} 86 87static 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 93static 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 135static 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 */ 154static 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 ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) { 173badblock: 174 printk(KERN_WARNING "mtdoops: bad block at %08lx\n", 175 cxt->nextpage * record_size); 176 i++; 177 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size); 178 if (cxt->nextpage >= cxt->oops_pages) 179 cxt->nextpage = 0; 180 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) { 181 printk(KERN_ERR "mtdoops: all blocks bad!\n"); 182 return; 183 } 184 } 185 186 if (ret < 0) { 187 printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n"); 188 return; 189 } 190 191 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) 192 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size); 193 194 if (ret >= 0) { 195 printk(KERN_DEBUG "mtdoops: ready %d, %d\n", 196 cxt->nextpage, cxt->nextcount); 197 return; 198 } 199 200 if (ret == -EIO) { 201 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size); 202 if (ret < 0 && ret != -EOPNOTSUPP) { 203 printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n"); 204 return; 205 } 206 } 207 goto badblock; 208} 209 210static void mtdoops_write(struct mtdoops_context *cxt, int panic) 211{ 212 struct mtd_info *mtd = cxt->mtd; 213 size_t retlen; 214 u32 *hdr; 215 int ret; 216 217 /* Add mtdoops header to the buffer */ 218 hdr = cxt->oops_buf; 219 hdr[0] = cxt->nextcount; 220 hdr[1] = MTDOOPS_KERNMSG_MAGIC; 221 222 if (panic) { 223 ret = mtd_panic_write(mtd, cxt->nextpage * record_size, 224 record_size, &retlen, cxt->oops_buf); 225 if (ret == -EOPNOTSUPP) { 226 printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); 227 return; 228 } 229 } else 230 ret = mtd_write(mtd, cxt->nextpage * record_size, 231 record_size, &retlen, cxt->oops_buf); 232 233 if (retlen != record_size || ret < 0) 234 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", 235 cxt->nextpage * record_size, retlen, record_size, ret); 236 mark_page_used(cxt, cxt->nextpage); 237 memset(cxt->oops_buf, 0xff, record_size); 238 239 mtdoops_inc_counter(cxt); 240} 241 242static void mtdoops_workfunc_write(struct work_struct *work) 243{ 244 struct mtdoops_context *cxt = 245 container_of(work, struct mtdoops_context, work_write); 246 247 mtdoops_write(cxt, 0); 248} 249 250static void find_next_position(struct mtdoops_context *cxt) 251{ 252 struct mtd_info *mtd = cxt->mtd; 253 int ret, page, maxpos = 0; 254 u32 count[2], maxcount = 0xffffffff; 255 size_t retlen; 256 257 for (page = 0; page < cxt->oops_pages; page++) { 258 if (mtd_block_isbad(mtd, page * record_size)) 259 continue; 260 /* Assume the page is used */ 261 mark_page_used(cxt, page); 262 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, 263 &retlen, (u_char *)&count[0]); 264 if (retlen != MTDOOPS_HEADER_SIZE || 265 (ret < 0 && !mtd_is_bitflip(ret))) { 266 printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", 267 page * record_size, retlen, 268 MTDOOPS_HEADER_SIZE, ret); 269 continue; 270 } 271 272 if (count[0] == 0xffffffff && count[1] == 0xffffffff) 273 mark_page_unused(cxt, page); 274 if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC) 275 continue; 276 if (maxcount == 0xffffffff) { 277 maxcount = count[0]; 278 maxpos = page; 279 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) { 280 maxcount = count[0]; 281 maxpos = page; 282 } else if (count[0] > maxcount && count[0] < 0xc0000000) { 283 maxcount = count[0]; 284 maxpos = page; 285 } else if (count[0] > maxcount && count[0] > 0xc0000000 286 && maxcount > 0x80000000) { 287 maxcount = count[0]; 288 maxpos = page; 289 } 290 } 291 if (maxcount == 0xffffffff) { 292 cxt->nextpage = cxt->oops_pages - 1; 293 cxt->nextcount = 0; 294 } 295 else { 296 cxt->nextpage = maxpos; 297 cxt->nextcount = maxcount; 298 } 299 300 mtdoops_inc_counter(cxt); 301} 302 303static void mtdoops_do_dump(struct kmsg_dumper *dumper, 304 enum kmsg_dump_reason reason) 305{ 306 struct mtdoops_context *cxt = container_of(dumper, 307 struct mtdoops_context, dump); 308 309 /* Only dump oopses if dump_oops is set */ 310 if (reason == KMSG_DUMP_OOPS && !dump_oops) 311 return; 312 313 kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, 314 record_size - MTDOOPS_HEADER_SIZE, NULL); 315 316 /* Panics must be written immediately */ 317 if (reason != KMSG_DUMP_OOPS) 318 mtdoops_write(cxt, 1); 319 320 /* For other cases, schedule work to write it "nicely" */ 321 schedule_work(&cxt->work_write); 322} 323 324static void mtdoops_notify_add(struct mtd_info *mtd) 325{ 326 struct mtdoops_context *cxt = &oops_cxt; 327 u64 mtdoops_pages = div_u64(mtd->size, record_size); 328 int err; 329 330 if (!strcmp(mtd->name, mtddev)) 331 cxt->mtd_index = mtd->index; 332 333 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 334 return; 335 336 if (mtd->size < mtd->erasesize * 2) { 337 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", 338 mtd->index); 339 return; 340 } 341 if (mtd->erasesize < record_size) { 342 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", 343 mtd->index); 344 return; 345 } 346 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { 347 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n", 348 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024); 349 return; 350 } 351 352 /* oops_page_used is a bit field */ 353 cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages, 354 BITS_PER_LONG) * sizeof(unsigned long)); 355 if (!cxt->oops_page_used) { 356 printk(KERN_ERR "mtdoops: could not allocate page array\n"); 357 return; 358 } 359 360 cxt->dump.max_reason = KMSG_DUMP_OOPS; 361 cxt->dump.dump = mtdoops_do_dump; 362 err = kmsg_dump_register(&cxt->dump); 363 if (err) { 364 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err); 365 vfree(cxt->oops_page_used); 366 cxt->oops_page_used = NULL; 367 return; 368 } 369 370 cxt->mtd = mtd; 371 cxt->oops_pages = (int)mtd->size / record_size; 372 find_next_position(cxt); 373 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 374} 375 376static void mtdoops_notify_remove(struct mtd_info *mtd) 377{ 378 struct mtdoops_context *cxt = &oops_cxt; 379 380 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 381 return; 382 383 if (kmsg_dump_unregister(&cxt->dump) < 0) 384 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n"); 385 386 cxt->mtd = NULL; 387 flush_work(&cxt->work_erase); 388 flush_work(&cxt->work_write); 389} 390 391 392static struct mtd_notifier mtdoops_notifier = { 393 .add = mtdoops_notify_add, 394 .remove = mtdoops_notify_remove, 395}; 396 397static int __init mtdoops_init(void) 398{ 399 struct mtdoops_context *cxt = &oops_cxt; 400 int mtd_index; 401 char *endp; 402 403 if (strlen(mtddev) == 0) { 404 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); 405 return -EINVAL; 406 } 407 if ((record_size & 4095) != 0) { 408 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); 409 return -EINVAL; 410 } 411 if (record_size < 4096) { 412 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); 413 return -EINVAL; 414 } 415 416 /* Setup the MTD device to use */ 417 cxt->mtd_index = -1; 418 mtd_index = simple_strtoul(mtddev, &endp, 0); 419 if (*endp == '\0') 420 cxt->mtd_index = mtd_index; 421 422 cxt->oops_buf = vmalloc(record_size); 423 if (!cxt->oops_buf) { 424 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); 425 return -ENOMEM; 426 } 427 memset(cxt->oops_buf, 0xff, record_size); 428 429 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 430 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 431 432 register_mtd_user(&mtdoops_notifier); 433 return 0; 434} 435 436static void __exit mtdoops_exit(void) 437{ 438 struct mtdoops_context *cxt = &oops_cxt; 439 440 unregister_mtd_user(&mtdoops_notifier); 441 vfree(cxt->oops_buf); 442 vfree(cxt->oops_page_used); 443} 444 445 446module_init(mtdoops_init); 447module_exit(mtdoops_exit); 448 449MODULE_LICENSE("GPL"); 450MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 451MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 452