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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * MTD Oops/Panic logger4 *5 * Copyright © 2007 Nokia Corporation. All rights reserved.6 *7 * Author: Richard Purdie <rpurdie@openedhand.com>8 */9 10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt11 12#include <linux/kernel.h>13#include <linux/module.h>14#include <linux/console.h>15#include <linux/vmalloc.h>16#include <linux/workqueue.h>17#include <linux/sched.h>18#include <linux/wait.h>19#include <linux/delay.h>20#include <linux/interrupt.h>21#include <linux/timekeeping.h>22#include <linux/mtd/mtd.h>23#include <linux/kmsg_dump.h>24 25/* Maximum MTD partition size */26#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)27 28static unsigned long record_size = 4096;29module_param(record_size, ulong, 0400);30MODULE_PARM_DESC(record_size,31 "record size for MTD OOPS pages in bytes (default 4096)");32 33static char mtddev[80];34module_param_string(mtddev, mtddev, 80, 0400);35MODULE_PARM_DESC(mtddev,36 "name or index number of the MTD device to use");37 38static int dump_oops = 1;39module_param(dump_oops, int, 0600);40MODULE_PARM_DESC(dump_oops,41 "set to 1 to dump oopses, 0 to only dump panics (default 1)");42 43#define MTDOOPS_KERNMSG_MAGIC_v1 0x5d005d00 /* Original */44#define MTDOOPS_KERNMSG_MAGIC_v2 0x5d005e00 /* Adds the timestamp */45 46struct mtdoops_hdr {47 u32 seq;48 u32 magic;49 ktime_t timestamp;50} __packed;51 52static struct mtdoops_context {53 struct kmsg_dumper dump;54 55 int mtd_index;56 struct work_struct work_erase;57 struct work_struct work_write;58 struct mtd_info *mtd;59 int oops_pages;60 int nextpage;61 int nextcount;62 unsigned long *oops_page_used;63 64 unsigned long oops_buf_busy;65 void *oops_buf;66} oops_cxt;67 68static void mark_page_used(struct mtdoops_context *cxt, int page)69{70 set_bit(page, cxt->oops_page_used);71}72 73static void mark_page_unused(struct mtdoops_context *cxt, int page)74{75 clear_bit(page, cxt->oops_page_used);76}77 78static int page_is_used(struct mtdoops_context *cxt, int page)79{80 return test_bit(page, cxt->oops_page_used);81}82 83static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)84{85 struct mtd_info *mtd = cxt->mtd;86 u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;87 u32 start_page = start_page_offset / record_size;88 u32 erase_pages = mtd->erasesize / record_size;89 struct erase_info erase;90 int ret;91 int page;92 93 erase.addr = offset;94 erase.len = mtd->erasesize;95 96 ret = mtd_erase(mtd, &erase);97 if (ret) {98 pr_warn("erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",99 (unsigned long long)erase.addr,100 (unsigned long long)erase.len, mtddev);101 return ret;102 }103 104 /* Mark pages as unused */105 for (page = start_page; page < start_page + erase_pages; page++)106 mark_page_unused(cxt, page);107 108 return 0;109}110 111static void mtdoops_erase(struct mtdoops_context *cxt)112{113 struct mtd_info *mtd = cxt->mtd;114 int i = 0, j, ret, mod;115 116 /* We were unregistered */117 if (!mtd)118 return;119 120 mod = (cxt->nextpage * record_size) % mtd->erasesize;121 if (mod != 0) {122 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);123 if (cxt->nextpage >= cxt->oops_pages)124 cxt->nextpage = 0;125 }126 127 while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {128badblock:129 pr_warn("bad block at %08lx\n",130 cxt->nextpage * record_size);131 i++;132 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);133 if (cxt->nextpage >= cxt->oops_pages)134 cxt->nextpage = 0;135 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {136 pr_err("all blocks bad!\n");137 return;138 }139 }140 141 if (ret < 0) {142 pr_err("mtd_block_isbad failed, aborting\n");143 return;144 }145 146 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)147 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);148 149 if (ret >= 0) {150 pr_debug("ready %d, %d\n",151 cxt->nextpage, cxt->nextcount);152 return;153 }154 155 if (ret == -EIO) {156 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);157 if (ret < 0 && ret != -EOPNOTSUPP) {158 pr_err("block_markbad failed, aborting\n");159 return;160 }161 }162 goto badblock;163}164 165/* Scheduled work - when we can't proceed without erasing a block */166static void mtdoops_workfunc_erase(struct work_struct *work)167{168 struct mtdoops_context *cxt =169 container_of(work, struct mtdoops_context, work_erase);170 mtdoops_erase(cxt);171}172 173static void mtdoops_inc_counter(struct mtdoops_context *cxt, int panic)174{175 cxt->nextpage++;176 if (cxt->nextpage >= cxt->oops_pages)177 cxt->nextpage = 0;178 cxt->nextcount++;179 if (cxt->nextcount == 0xffffffff)180 cxt->nextcount = 0;181 182 if (page_is_used(cxt, cxt->nextpage)) {183 pr_debug("not ready %d, %d (erase %s)\n",184 cxt->nextpage, cxt->nextcount,185 panic ? "immediately" : "scheduled");186 if (panic) {187 /* In case of panic, erase immediately */188 mtdoops_erase(cxt);189 } else {190 /* Otherwise, schedule work to erase it "nicely" */191 schedule_work(&cxt->work_erase);192 }193 } else {194 pr_debug("ready %d, %d (no erase)\n",195 cxt->nextpage, cxt->nextcount);196 }197}198 199static void mtdoops_write(struct mtdoops_context *cxt, int panic)200{201 struct mtd_info *mtd = cxt->mtd;202 size_t retlen;203 struct mtdoops_hdr *hdr;204 int ret;205 206 if (test_and_set_bit(0, &cxt->oops_buf_busy))207 return;208 209 /* Add mtdoops header to the buffer */210 hdr = (struct mtdoops_hdr *)cxt->oops_buf;211 hdr->seq = cxt->nextcount;212 hdr->magic = MTDOOPS_KERNMSG_MAGIC_v2;213 hdr->timestamp = ktime_get_real();214 215 if (panic) {216 ret = mtd_panic_write(mtd, cxt->nextpage * record_size,217 record_size, &retlen, cxt->oops_buf);218 if (ret == -EOPNOTSUPP) {219 pr_err("Cannot write from panic without panic_write\n");220 goto out;221 }222 } else223 ret = mtd_write(mtd, cxt->nextpage * record_size,224 record_size, &retlen, cxt->oops_buf);225 226 if (retlen != record_size || ret < 0)227 pr_err("write failure at %ld (%td of %ld written), error %d\n",228 cxt->nextpage * record_size, retlen, record_size, ret);229 mark_page_used(cxt, cxt->nextpage);230 memset(cxt->oops_buf, 0xff, record_size);231 232 mtdoops_inc_counter(cxt, panic);233out:234 clear_bit(0, &cxt->oops_buf_busy);235}236 237static void mtdoops_workfunc_write(struct work_struct *work)238{239 struct mtdoops_context *cxt =240 container_of(work, struct mtdoops_context, work_write);241 242 mtdoops_write(cxt, 0);243}244 245static void find_next_position(struct mtdoops_context *cxt)246{247 struct mtd_info *mtd = cxt->mtd;248 struct mtdoops_hdr hdr;249 int ret, page, maxpos = 0;250 u32 maxcount = 0xffffffff;251 size_t retlen;252 253 for (page = 0; page < cxt->oops_pages; page++) {254 if (mtd_block_isbad(mtd, page * record_size))255 continue;256 /* Assume the page is used */257 mark_page_used(cxt, page);258 ret = mtd_read(mtd, page * record_size, sizeof(hdr),259 &retlen, (u_char *)&hdr);260 if (retlen != sizeof(hdr) ||261 (ret < 0 && !mtd_is_bitflip(ret))) {262 pr_err("read failure at %ld (%zu of %zu read), err %d\n",263 page * record_size, retlen, sizeof(hdr), ret);264 continue;265 }266 267 if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)268 mark_page_unused(cxt, page);269 if (hdr.seq == 0xffffffff ||270 (hdr.magic != MTDOOPS_KERNMSG_MAGIC_v1 &&271 hdr.magic != MTDOOPS_KERNMSG_MAGIC_v2))272 continue;273 if (maxcount == 0xffffffff) {274 maxcount = hdr.seq;275 maxpos = page;276 } else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {277 maxcount = hdr.seq;278 maxpos = page;279 } else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {280 maxcount = hdr.seq;281 maxpos = page;282 } else if (hdr.seq > maxcount && hdr.seq > 0xc0000000283 && maxcount > 0x80000000) {284 maxcount = hdr.seq;285 maxpos = page;286 }287 }288 if (maxcount == 0xffffffff) {289 cxt->nextpage = cxt->oops_pages - 1;290 cxt->nextcount = 0;291 }292 else {293 cxt->nextpage = maxpos;294 cxt->nextcount = maxcount;295 }296 297 mtdoops_inc_counter(cxt, 0);298}299 300static void mtdoops_do_dump(struct kmsg_dumper *dumper,301 struct kmsg_dump_detail *detail)302{303 struct mtdoops_context *cxt = container_of(dumper,304 struct mtdoops_context, dump);305 struct kmsg_dump_iter iter;306 307 /* Only dump oopses if dump_oops is set */308 if (detail->reason == KMSG_DUMP_OOPS && !dump_oops)309 return;310 311 kmsg_dump_rewind(&iter);312 313 if (test_and_set_bit(0, &cxt->oops_buf_busy))314 return;315 kmsg_dump_get_buffer(&iter, true,316 cxt->oops_buf + sizeof(struct mtdoops_hdr),317 record_size - sizeof(struct mtdoops_hdr), NULL);318 clear_bit(0, &cxt->oops_buf_busy);319 320 if (detail->reason != KMSG_DUMP_OOPS) {321 /* Panics must be written immediately */322 mtdoops_write(cxt, 1);323 } else {324 /* For other cases, schedule work to write it "nicely" */325 schedule_work(&cxt->work_write);326 }327}328 329static void mtdoops_notify_add(struct mtd_info *mtd)330{331 struct mtdoops_context *cxt = &oops_cxt;332 u64 mtdoops_pages = div_u64(mtd->size, record_size);333 int err;334 335 if (!strcmp(mtd->name, mtddev))336 cxt->mtd_index = mtd->index;337 338 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)339 return;340 341 if (mtd->size < mtd->erasesize * 2) {342 pr_err("MTD partition %d not big enough for mtdoops\n",343 mtd->index);344 return;345 }346 if (mtd->erasesize < record_size) {347 pr_err("eraseblock size of MTD partition %d too small\n",348 mtd->index);349 return;350 }351 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {352 pr_err("mtd%d is too large (limit is %d MiB)\n",353 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);354 return;355 }356 357 /* oops_page_used is a bit field */358 cxt->oops_page_used =359 vmalloc(array_size(sizeof(unsigned long),360 DIV_ROUND_UP(mtdoops_pages,361 BITS_PER_LONG)));362 if (!cxt->oops_page_used) {363 pr_err("could not allocate page array\n");364 return;365 }366 367 cxt->dump.max_reason = KMSG_DUMP_OOPS;368 cxt->dump.dump = mtdoops_do_dump;369 err = kmsg_dump_register(&cxt->dump);370 if (err) {371 pr_err("registering kmsg dumper failed, error %d\n", err);372 vfree(cxt->oops_page_used);373 cxt->oops_page_used = NULL;374 return;375 }376 377 cxt->mtd = mtd;378 cxt->oops_pages = (int)mtd->size / record_size;379 find_next_position(cxt);380 pr_info("Attached to MTD device %d\n", mtd->index);381}382 383static void mtdoops_notify_remove(struct mtd_info *mtd)384{385 struct mtdoops_context *cxt = &oops_cxt;386 387 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)388 return;389 390 if (kmsg_dump_unregister(&cxt->dump) < 0)391 pr_warn("could not unregister kmsg_dumper\n");392 393 cxt->mtd = NULL;394 flush_work(&cxt->work_erase);395 flush_work(&cxt->work_write);396}397 398 399static struct mtd_notifier mtdoops_notifier = {400 .add = mtdoops_notify_add,401 .remove = mtdoops_notify_remove,402};403 404static int __init mtdoops_init(void)405{406 struct mtdoops_context *cxt = &oops_cxt;407 int mtd_index;408 char *endp;409 410 if (strlen(mtddev) == 0) {411 pr_err("mtd device (mtddev=name/number) must be supplied\n");412 return -EINVAL;413 }414 if ((record_size & 4095) != 0) {415 pr_err("record_size must be a multiple of 4096\n");416 return -EINVAL;417 }418 if (record_size < 4096) {419 pr_err("record_size must be over 4096 bytes\n");420 return -EINVAL;421 }422 423 /* Setup the MTD device to use */424 cxt->mtd_index = -1;425 mtd_index = simple_strtoul(mtddev, &endp, 0);426 if (*endp == '\0')427 cxt->mtd_index = mtd_index;428 429 cxt->oops_buf = vmalloc(record_size);430 if (!cxt->oops_buf)431 return -ENOMEM;432 memset(cxt->oops_buf, 0xff, record_size);433 cxt->oops_buf_busy = 0;434 435 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);436 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);437 438 register_mtd_user(&mtdoops_notifier);439 return 0;440}441 442static void __exit mtdoops_exit(void)443{444 struct mtdoops_context *cxt = &oops_cxt;445 446 unregister_mtd_user(&mtdoops_notifier);447 vfree(cxt->oops_buf);448 vfree(cxt->oops_page_used);449}450 451 452module_init(mtdoops_init);453module_exit(mtdoops_exit);454 455MODULE_LICENSE("GPL");456MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");457MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");458