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/mtd/mtd.h> 20 #include <linux/kmsg_dump.h> 21 22 /* Maximum MTD partition size */ 23 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024) 24 25 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00 26 #define MTDOOPS_HEADER_SIZE 8 27 28 static unsigned long record_size = 4096; 29 module_param(record_size, ulong, 0400); 30 MODULE_PARM_DESC(record_size, 31 "record size for MTD OOPS pages in bytes (default 4096)"); 32 33 static char mtddev[80]; 34 module_param_string(mtddev, mtddev, 80, 0400); 35 MODULE_PARM_DESC(mtddev, 36 "name or index number of the MTD device to use"); 37 38 static int dump_oops = 1; 39 module_param(dump_oops, int, 0600); 40 MODULE_PARM_DESC(dump_oops, 41 "set to 1 to dump oopses, 0 to only dump panics (default 1)"); 42 43 static struct mtdoops_context { 44 struct kmsg_dumper dump; 45 46 int mtd_index; 47 struct work_struct work_erase; 48 struct work_struct work_write; 49 struct mtd_info *mtd; 50 int oops_pages; 51 int nextpage; 52 int nextcount; 53 unsigned long *oops_page_used; 54 55 void *oops_buf; 56 } oops_cxt; 57 58 static void mark_page_used(struct mtdoops_context *cxt, int page) 59 { 60 set_bit(page, cxt->oops_page_used); 61 } 62 63 static void mark_page_unused(struct mtdoops_context *cxt, int page) 64 { 65 clear_bit(page, cxt->oops_page_used); 66 } 67 68 static int page_is_used(struct mtdoops_context *cxt, int page) 69 { 70 return test_bit(page, cxt->oops_page_used); 71 } 72 73 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset) 74 { 75 struct mtd_info *mtd = cxt->mtd; 76 u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize; 77 u32 start_page = start_page_offset / record_size; 78 u32 erase_pages = mtd->erasesize / record_size; 79 struct erase_info erase; 80 int ret; 81 int page; 82 83 erase.addr = offset; 84 erase.len = mtd->erasesize; 85 86 ret = mtd_erase(mtd, &erase); 87 if (ret) { 88 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n", 89 (unsigned long long)erase.addr, 90 (unsigned long long)erase.len, mtddev); 91 return ret; 92 } 93 94 /* Mark pages as unused */ 95 for (page = start_page; page < start_page + erase_pages; page++) 96 mark_page_unused(cxt, page); 97 98 return 0; 99 } 100 101 static void mtdoops_inc_counter(struct mtdoops_context *cxt) 102 { 103 cxt->nextpage++; 104 if (cxt->nextpage >= cxt->oops_pages) 105 cxt->nextpage = 0; 106 cxt->nextcount++; 107 if (cxt->nextcount == 0xffffffff) 108 cxt->nextcount = 0; 109 110 if (page_is_used(cxt, cxt->nextpage)) { 111 schedule_work(&cxt->work_erase); 112 return; 113 } 114 115 printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n", 116 cxt->nextpage, cxt->nextcount); 117 } 118 119 /* Scheduled work - when we can't proceed without erasing a block */ 120 static void mtdoops_workfunc_erase(struct work_struct *work) 121 { 122 struct mtdoops_context *cxt = 123 container_of(work, struct mtdoops_context, work_erase); 124 struct mtd_info *mtd = cxt->mtd; 125 int i = 0, j, ret, mod; 126 127 /* We were unregistered */ 128 if (!mtd) 129 return; 130 131 mod = (cxt->nextpage * record_size) % mtd->erasesize; 132 if (mod != 0) { 133 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size); 134 if (cxt->nextpage >= cxt->oops_pages) 135 cxt->nextpage = 0; 136 } 137 138 while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) { 139 badblock: 140 printk(KERN_WARNING "mtdoops: bad block at %08lx\n", 141 cxt->nextpage * record_size); 142 i++; 143 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size); 144 if (cxt->nextpage >= cxt->oops_pages) 145 cxt->nextpage = 0; 146 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) { 147 printk(KERN_ERR "mtdoops: all blocks bad!\n"); 148 return; 149 } 150 } 151 152 if (ret < 0) { 153 printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n"); 154 return; 155 } 156 157 for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) 158 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size); 159 160 if (ret >= 0) { 161 printk(KERN_DEBUG "mtdoops: ready %d, %d\n", 162 cxt->nextpage, cxt->nextcount); 163 return; 164 } 165 166 if (ret == -EIO) { 167 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size); 168 if (ret < 0 && ret != -EOPNOTSUPP) { 169 printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n"); 170 return; 171 } 172 } 173 goto badblock; 174 } 175 176 static void mtdoops_write(struct mtdoops_context *cxt, int panic) 177 { 178 struct mtd_info *mtd = cxt->mtd; 179 size_t retlen; 180 u32 *hdr; 181 int ret; 182 183 /* Add mtdoops header to the buffer */ 184 hdr = cxt->oops_buf; 185 hdr[0] = cxt->nextcount; 186 hdr[1] = MTDOOPS_KERNMSG_MAGIC; 187 188 if (panic) { 189 ret = mtd_panic_write(mtd, cxt->nextpage * record_size, 190 record_size, &retlen, cxt->oops_buf); 191 if (ret == -EOPNOTSUPP) { 192 printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n"); 193 return; 194 } 195 } else 196 ret = mtd_write(mtd, cxt->nextpage * record_size, 197 record_size, &retlen, cxt->oops_buf); 198 199 if (retlen != record_size || ret < 0) 200 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n", 201 cxt->nextpage * record_size, retlen, record_size, ret); 202 mark_page_used(cxt, cxt->nextpage); 203 memset(cxt->oops_buf, 0xff, record_size); 204 205 mtdoops_inc_counter(cxt); 206 } 207 208 static void mtdoops_workfunc_write(struct work_struct *work) 209 { 210 struct mtdoops_context *cxt = 211 container_of(work, struct mtdoops_context, work_write); 212 213 mtdoops_write(cxt, 0); 214 } 215 216 static void find_next_position(struct mtdoops_context *cxt) 217 { 218 struct mtd_info *mtd = cxt->mtd; 219 int ret, page, maxpos = 0; 220 u32 count[2], maxcount = 0xffffffff; 221 size_t retlen; 222 223 for (page = 0; page < cxt->oops_pages; page++) { 224 if (mtd_block_isbad(mtd, page * record_size)) 225 continue; 226 /* Assume the page is used */ 227 mark_page_used(cxt, page); 228 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE, 229 &retlen, (u_char *)&count[0]); 230 if (retlen != MTDOOPS_HEADER_SIZE || 231 (ret < 0 && !mtd_is_bitflip(ret))) { 232 printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n", 233 page * record_size, retlen, 234 MTDOOPS_HEADER_SIZE, ret); 235 continue; 236 } 237 238 if (count[0] == 0xffffffff && count[1] == 0xffffffff) 239 mark_page_unused(cxt, page); 240 if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC) 241 continue; 242 if (maxcount == 0xffffffff) { 243 maxcount = count[0]; 244 maxpos = page; 245 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) { 246 maxcount = count[0]; 247 maxpos = page; 248 } else if (count[0] > maxcount && count[0] < 0xc0000000) { 249 maxcount = count[0]; 250 maxpos = page; 251 } else if (count[0] > maxcount && count[0] > 0xc0000000 252 && maxcount > 0x80000000) { 253 maxcount = count[0]; 254 maxpos = page; 255 } 256 } 257 if (maxcount == 0xffffffff) { 258 cxt->nextpage = cxt->oops_pages - 1; 259 cxt->nextcount = 0; 260 } 261 else { 262 cxt->nextpage = maxpos; 263 cxt->nextcount = maxcount; 264 } 265 266 mtdoops_inc_counter(cxt); 267 } 268 269 static void mtdoops_do_dump(struct kmsg_dumper *dumper, 270 enum kmsg_dump_reason reason) 271 { 272 struct mtdoops_context *cxt = container_of(dumper, 273 struct mtdoops_context, dump); 274 275 /* Only dump oopses if dump_oops is set */ 276 if (reason == KMSG_DUMP_OOPS && !dump_oops) 277 return; 278 279 kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, 280 record_size - MTDOOPS_HEADER_SIZE, NULL); 281 282 /* Panics must be written immediately */ 283 if (reason != KMSG_DUMP_OOPS) 284 mtdoops_write(cxt, 1); 285 286 /* For other cases, schedule work to write it "nicely" */ 287 schedule_work(&cxt->work_write); 288 } 289 290 static void mtdoops_notify_add(struct mtd_info *mtd) 291 { 292 struct mtdoops_context *cxt = &oops_cxt; 293 u64 mtdoops_pages = div_u64(mtd->size, record_size); 294 int err; 295 296 if (!strcmp(mtd->name, mtddev)) 297 cxt->mtd_index = mtd->index; 298 299 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 300 return; 301 302 if (mtd->size < mtd->erasesize * 2) { 303 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n", 304 mtd->index); 305 return; 306 } 307 if (mtd->erasesize < record_size) { 308 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n", 309 mtd->index); 310 return; 311 } 312 if (mtd->size > MTDOOPS_MAX_MTD_SIZE) { 313 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n", 314 mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024); 315 return; 316 } 317 318 /* oops_page_used is a bit field */ 319 cxt->oops_page_used = 320 vmalloc(array_size(sizeof(unsigned long), 321 DIV_ROUND_UP(mtdoops_pages, 322 BITS_PER_LONG))); 323 if (!cxt->oops_page_used) { 324 printk(KERN_ERR "mtdoops: could not allocate page array\n"); 325 return; 326 } 327 328 cxt->dump.max_reason = KMSG_DUMP_OOPS; 329 cxt->dump.dump = mtdoops_do_dump; 330 err = kmsg_dump_register(&cxt->dump); 331 if (err) { 332 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err); 333 vfree(cxt->oops_page_used); 334 cxt->oops_page_used = NULL; 335 return; 336 } 337 338 cxt->mtd = mtd; 339 cxt->oops_pages = (int)mtd->size / record_size; 340 find_next_position(cxt); 341 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index); 342 } 343 344 static void mtdoops_notify_remove(struct mtd_info *mtd) 345 { 346 struct mtdoops_context *cxt = &oops_cxt; 347 348 if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0) 349 return; 350 351 if (kmsg_dump_unregister(&cxt->dump) < 0) 352 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n"); 353 354 cxt->mtd = NULL; 355 flush_work(&cxt->work_erase); 356 flush_work(&cxt->work_write); 357 } 358 359 360 static struct mtd_notifier mtdoops_notifier = { 361 .add = mtdoops_notify_add, 362 .remove = mtdoops_notify_remove, 363 }; 364 365 static int __init mtdoops_init(void) 366 { 367 struct mtdoops_context *cxt = &oops_cxt; 368 int mtd_index; 369 char *endp; 370 371 if (strlen(mtddev) == 0) { 372 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n"); 373 return -EINVAL; 374 } 375 if ((record_size & 4095) != 0) { 376 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n"); 377 return -EINVAL; 378 } 379 if (record_size < 4096) { 380 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n"); 381 return -EINVAL; 382 } 383 384 /* Setup the MTD device to use */ 385 cxt->mtd_index = -1; 386 mtd_index = simple_strtoul(mtddev, &endp, 0); 387 if (*endp == '\0') 388 cxt->mtd_index = mtd_index; 389 390 cxt->oops_buf = vmalloc(record_size); 391 if (!cxt->oops_buf) { 392 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n"); 393 return -ENOMEM; 394 } 395 memset(cxt->oops_buf, 0xff, record_size); 396 397 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase); 398 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write); 399 400 register_mtd_user(&mtdoops_notifier); 401 return 0; 402 } 403 404 static void __exit mtdoops_exit(void) 405 { 406 struct mtdoops_context *cxt = &oops_cxt; 407 408 unregister_mtd_user(&mtdoops_notifier); 409 vfree(cxt->oops_buf); 410 vfree(cxt->oops_page_used); 411 } 412 413 414 module_init(mtdoops_init); 415 module_exit(mtdoops_exit); 416 417 MODULE_LICENSE("GPL"); 418 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>"); 419 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver"); 420