1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * MTD Oops/Panic logger 4 * 5 * Copyright © 2007 Nokia Corporation. All rights reserved. 6 * 7 * Author: Richard Purdie <rpurdie@openedhand.com> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/console.h> 13 #include <linux/vmalloc.h> 14 #include <linux/workqueue.h> 15 #include <linux/sched.h> 16 #include <linux/wait.h> 17 #include <linux/delay.h> 18 #include <linux/interrupt.h> 19 #include <linux/timekeeping.h> 20 #include <linux/mtd/mtd.h> 21 #include <linux/kmsg_dump.h> 22 23 /* Maximum MTD partition size */ 24 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024) 25 26 static unsigned long record_size = 4096; 27 module_param(record_size, ulong, 0400); 28 MODULE_PARM_DESC(record_size, 29 "record size for MTD OOPS pages in bytes (default 4096)"); 30 31 static char mtddev[80]; 32 module_param_string(mtddev, mtddev, 80, 0400); 33 MODULE_PARM_DESC(mtddev, 34 "name or index number of the MTD device to use"); 35 36 static int dump_oops = 1; 37 module_param(dump_oops, int, 0600); 38 MODULE_PARM_DESC(dump_oops, 39 "set to 1 to dump oopses, 0 to only dump panics (default 1)"); 40 41 #define MTDOOPS_KERNMSG_MAGIC_v1 0x5d005d00 /* Original */ 42 #define MTDOOPS_KERNMSG_MAGIC_v2 0x5d005e00 /* Adds the timestamp */ 43 44 struct mtdoops_hdr { 45 u32 seq; 46 u32 magic; 47 ktime_t timestamp; 48 } __packed; 49 50 static struct mtdoops_context { 51 struct kmsg_dumper dump; 52 53 int mtd_index; 54 struct work_struct work_erase; 55 struct work_struct work_write; 56 struct mtd_info *mtd; 57 int oops_pages; 58 int nextpage; 59 int nextcount; 60 unsigned long *oops_page_used; 61 62 unsigned long oops_buf_busy; 63 void *oops_buf; 64 } oops_cxt; 65 66 static void mark_page_used(struct mtdoops_context *cxt, int page) 67 { 68 set_bit(page, cxt->oops_page_used); 69 } 70 71 static void mark_page_unused(struct mtdoops_context *cxt, int page) 72 { 73 clear_bit(page, cxt->oops_page_used); 74 } 75 76 static int page_is_used(struct mtdoops_context *cxt, int page) 77 { 78 return test_bit(page, cxt->oops_page_used); 79 } 80 81 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset) 82 { 83 struct mtd_info *mtd = cxt->mtd; 84 u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize; 85 u32 start_page = start_page_offset / record_size; 86 u32 erase_pages = mtd->erasesize / record_size; 87 struct erase_info erase; 88 int ret; 89 int page; 90 91 erase.addr = offset; 92 erase.len = mtd->erasesize; 93 94 ret = mtd_erase(mtd, &erase); 95 if (ret) { 96 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", 97 (unsigned long long)erase.addr, 98 (unsigned long long)erase.len, mtddev); 99 return ret; 100 } 101 102 /* Mark pages as unused */ 103 for (page = start_page; page < start_page + erase_pages; page++) 104 mark_page_unused(cxt, page); 105 106 return 0; 107 } 108 109 static void mtdoops_inc_counter(struct mtdoops_context *cxt) 110 { 111 cxt->nextpage++; 112 if (cxt->nextpage >= cxt->oops_pages) 113 cxt->nextpage = 0; 114 cxt->nextcount++; 115 if (cxt->nextcount == 0xffffffff) 116 cxt->nextcount = 0; 117 118 if (page_is_used(cxt, cxt->nextpage)) { 119 schedule_work(&cxt->work_erase); 120 return; 121 } 122 123 printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", 124 cxt->nextpage, cxt->nextcount); 125 } 126 127 /* Scheduled work - when we can't proceed without erasing a block */ 128 static void mtdoops_workfunc_erase(struct work_struct *work) 129 { 130 struct mtdoops_context *cxt = 131 container_of(work, struct mtdoops_context, work_erase); 132 struct mtd_info *mtd = cxt->mtd; 133 int i = 0, j, ret, mod; 134 135 /* We were unregistered */ 136 if (!mtd) 137 return; 138 139 mod = (cxt->nextpage * record_size) % mtd->erasesize; 140 if (mod != 0) { 141 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size); 142 if (cxt->nextpage >= cxt->oops_pages) 143 cxt->nextpage = 0; 144 } 145 146 while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) { 147 badblock: 148 printk(KERN_WARNING "mtdoops: bad block at %08lx\n", 149 cxt->nextpage * record_size); 150 i++; 151 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size); 152 if (cxt->nextpage >= cxt->oops_pages) 153 cxt->nextpage = 0; 154 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) { 155 printk(KERN_ERR "mtdoops: all blocks bad!\n"); 156 return; 157 } 158 } 159 160 if (ret < 0) { 161 printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n"); 162 return; 163 } 164 165 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) 166 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size); 167 168 if (ret >= 0) { 169 printk(KERN_DEBUG "mtdoops: ready %d, %d\n", 170 cxt->nextpage, cxt->nextcount); 171 return; 172 } 173 174 if (ret == -EIO) { 175 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size); 176 if (ret < 0 && ret != -EOPNOTSUPP) { 177 printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n"); 178 return; 179 } 180 } 181 goto badblock; 182 } 183 184 static void mtdoops_write(struct mtdoops_context *cxt, int panic) 185 { 186 struct mtd_info *mtd = cxt->mtd; 187 size_t retlen; 188 struct mtdoops_hdr *hdr; 189 int ret; 190 191 if (test_and_set_bit(0, &cxt->oops_buf_busy)) 192 return; 193 194 /* Add mtdoops header to the buffer */ 195 hdr = (struct mtdoops_hdr *)cxt->oops_buf; 196 hdr->seq = cxt->nextcount; 197 hdr->magic = MTDOOPS_KERNMSG_MAGIC_v2; 198 hdr->timestamp = ktime_get_real(); 199 200 if (panic) { 201 ret = mtd_panic_write(mtd, cxt->nextpage * record_size, 202 record_size, &retlen, cxt->oops_buf); 203 if (ret == -EOPNOTSUPP) { 204 printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); 205 goto out; 206 } 207 } else 208 ret = mtd_write(mtd, cxt->nextpage * record_size, 209 record_size, &retlen, cxt->oops_buf); 210 211 if (retlen != record_size || ret < 0) 212 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", 213 cxt->nextpage * record_size, retlen, record_size, ret); 214 mark_page_used(cxt, cxt->nextpage); 215 memset(cxt->oops_buf, 0xff, record_size); 216 217 mtdoops_inc_counter(cxt); 218 out: 219 clear_bit(0, &cxt->oops_buf_busy); 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 struct mtdoops_hdr hdr; 234 int ret, page, maxpos = 0; 235 u32 maxcount = 0xffffffff; 236 size_t retlen; 237 238 for (page = 0; page < cxt->oops_pages; page++) { 239 if (mtd_block_isbad(mtd, page * record_size)) 240 continue; 241 /* Assume the page is used */ 242 mark_page_used(cxt, page); 243 ret = mtd_read(mtd, page * record_size, sizeof(hdr), 244 &retlen, (u_char *)&hdr); 245 if (retlen != sizeof(hdr) || 246 (ret < 0 && !mtd_is_bitflip(ret))) { 247 printk(KERN_ERR "mtdoops: read failure at %ld (%zu of %zu read), err %d\n", 248 page * record_size, retlen, sizeof(hdr), ret); 249 continue; 250 } 251 252 if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff) 253 mark_page_unused(cxt, page); 254 if (hdr.seq == 0xffffffff || 255 (hdr.magic != MTDOOPS_KERNMSG_MAGIC_v1 && 256 hdr.magic != MTDOOPS_KERNMSG_MAGIC_v2)) 257 continue; 258 if (maxcount == 0xffffffff) { 259 maxcount = hdr.seq; 260 maxpos = page; 261 } else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) { 262 maxcount = hdr.seq; 263 maxpos = page; 264 } else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) { 265 maxcount = hdr.seq; 266 maxpos = page; 267 } else if (hdr.seq > maxcount && hdr.seq > 0xc0000000 268 && maxcount > 0x80000000) { 269 maxcount = hdr.seq; 270 maxpos = page; 271 } 272 } 273 if (maxcount == 0xffffffff) { 274 cxt->nextpage = cxt->oops_pages - 1; 275 cxt->nextcount = 0; 276 } 277 else { 278 cxt->nextpage = maxpos; 279 cxt->nextcount = maxcount; 280 } 281 282 mtdoops_inc_counter(cxt); 283 } 284 285 static void mtdoops_do_dump(struct kmsg_dumper *dumper, 286 enum kmsg_dump_reason reason) 287 { 288 struct mtdoops_context *cxt = container_of(dumper, 289 struct mtdoops_context, dump); 290 struct kmsg_dump_iter iter; 291 292 /* Only dump oopses if dump_oops is set */ 293 if (reason == KMSG_DUMP_OOPS && !dump_oops) 294 return; 295 296 kmsg_dump_rewind(&iter); 297 298 if (test_and_set_bit(0, &cxt->oops_buf_busy)) 299 return; 300 kmsg_dump_get_buffer(&iter, true, 301 cxt->oops_buf + sizeof(struct mtdoops_hdr), 302 record_size - sizeof(struct mtdoops_hdr), NULL); 303 clear_bit(0, &cxt->oops_buf_busy); 304 305 if (reason != KMSG_DUMP_OOPS) { 306 /* Panics must be written immediately */ 307 mtdoops_write(cxt, 1); 308 } else { 309 /* For other cases, schedule work to write it "nicely" */ 310 schedule_work(&cxt->work_write); 311 } 312 } 313 314 static void mtdoops_notify_add(struct mtd_info *mtd) 315 { 316 struct mtdoops_context *cxt = &oops_cxt; 317 u64 mtdoops_pages = div_u64(mtd->size, record_size); 318 int err; 319 320 if (!strcmp(mtd->name, mtddev)) 321 cxt->mtd_index = mtd->index; 322 323 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 324 return; 325 326 if (mtd->size < mtd->erasesize * 2) { 327 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", 328 mtd->index); 329 return; 330 } 331 if (mtd->erasesize < record_size) { 332 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", 333 mtd->index); 334 return; 335 } 336 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { 337 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n", 338 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024); 339 return; 340 } 341 342 /* oops_page_used is a bit field */ 343 cxt->oops_page_used = 344 vmalloc(array_size(sizeof(unsigned long), 345 DIV_ROUND_UP(mtdoops_pages, 346 BITS_PER_LONG))); 347 if (!cxt->oops_page_used) { 348 printk(KERN_ERR "mtdoops: could not allocate page array\n"); 349 return; 350 } 351 352 cxt->dump.max_reason = KMSG_DUMP_OOPS; 353 cxt->dump.dump = mtdoops_do_dump; 354 err = kmsg_dump_register(&cxt->dump); 355 if (err) { 356 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err); 357 vfree(cxt->oops_page_used); 358 cxt->oops_page_used = NULL; 359 return; 360 } 361 362 cxt->mtd = mtd; 363 cxt->oops_pages = (int)mtd->size / record_size; 364 find_next_position(cxt); 365 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 366 } 367 368 static void mtdoops_notify_remove(struct mtd_info *mtd) 369 { 370 struct mtdoops_context *cxt = &oops_cxt; 371 372 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 373 return; 374 375 if (kmsg_dump_unregister(&cxt->dump) < 0) 376 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n"); 377 378 cxt->mtd = NULL; 379 flush_work(&cxt->work_erase); 380 flush_work(&cxt->work_write); 381 } 382 383 384 static struct mtd_notifier mtdoops_notifier = { 385 .add = mtdoops_notify_add, 386 .remove = mtdoops_notify_remove, 387 }; 388 389 static int __init mtdoops_init(void) 390 { 391 struct mtdoops_context *cxt = &oops_cxt; 392 int mtd_index; 393 char *endp; 394 395 if (strlen(mtddev) == 0) { 396 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); 397 return -EINVAL; 398 } 399 if ((record_size & 4095) != 0) { 400 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); 401 return -EINVAL; 402 } 403 if (record_size < 4096) { 404 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); 405 return -EINVAL; 406 } 407 408 /* Setup the MTD device to use */ 409 cxt->mtd_index = -1; 410 mtd_index = simple_strtoul(mtddev, &endp, 0); 411 if (*endp == '\0') 412 cxt->mtd_index = mtd_index; 413 414 cxt->oops_buf = vmalloc(record_size); 415 if (!cxt->oops_buf) 416 return -ENOMEM; 417 memset(cxt->oops_buf, 0xff, record_size); 418 cxt->oops_buf_busy = 0; 419 420 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 421 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 422 423 register_mtd_user(&mtdoops_notifier); 424 return 0; 425 } 426 427 static void __exit mtdoops_exit(void) 428 { 429 struct mtdoops_context *cxt = &oops_cxt; 430 431 unregister_mtd_user(&mtdoops_notifier); 432 vfree(cxt->oops_buf); 433 vfree(cxt->oops_page_used); 434 } 435 436 437 module_init(mtdoops_init); 438 module_exit(mtdoops_exit); 439 440 MODULE_LICENSE("GPL"); 441 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 442 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 443