fs/pstore/ram.c

   1 /*
   2  * RAM Oops/Panic logger
   3  *
   4  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
   5  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * version 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  19  * 02110-1301 USA
  20  *
  21  */
  22
  23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/kernel.h>
  26 #include <linux/err.h>
  27 #include <linux/module.h>
  28 #include <linux/version.h>
  29 #include <linux/pstore.h>
  30 #include <linux/time.h>
  31 #include <linux/io.h>
  32 #include <linux/ioport.h>
  33 #include <linux/platform_device.h>
  34 #include <linux/slab.h>
  35 #include <linux/compiler.h>
  36 #include <linux/pstore_ram.h>
  37
  38 #define RAMOOPS_KERNMSG_HDR "===="
  39 #define MIN_MEM_SIZE 4096UL
  40
  41 static ulong record_size = MIN_MEM_SIZE;
  42 module_param(record_size, ulong, 0400);
  43 MODULE_PARM_DESC(record_size,
  44                 "size of each dump done on oops/panic");
  45
  46 static ulong ramoops_console_size = MIN_MEM_SIZE;
  47 module_param_named(console_size, ramoops_console_size, ulong, 0400);
  48 MODULE_PARM_DESC(console_size, "size of kernel console log");
  49
  50 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  51 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  52 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  53
  54 static ulong mem_address;
  55 module_param(mem_address, ulong, 0400);
  56 MODULE_PARM_DESC(mem_address,
  57                 "start of reserved RAM used to store oops/panic logs");
  58
  59 static ulong mem_size;
  60 module_param(mem_size, ulong, 0400);
  61 MODULE_PARM_DESC(mem_size,
  62                 "size of reserved RAM used to store oops/panic logs");
  63
  64 static int dump_oops = 1;
  65 module_param(dump_oops, int, 0600);
  66 MODULE_PARM_DESC(dump_oops,
  67                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  68
  69 static int ramoops_ecc;
  70 module_param_named(ecc, ramoops_ecc, int, 0600);
  71 MODULE_PARM_DESC(ramoops_ecc,
  72                 "if non-zero, the option enables ECC support and specifies "
  73                 "ECC buffer size in bytes (1 is a special value, means 16 "
  74                 "bytes ECC)");
  75
  76 struct ramoops_context {
  77         struct persistent_ram_zone **przs;
  78         struct persistent_ram_zone *cprz;
  79         struct persistent_ram_zone *fprz;
  80         phys_addr_t phys_addr;
  81         unsigned long size;
  82         size_t record_size;
  83         size_t console_size;
  84         size_t ftrace_size;
  85         int dump_oops;
  86         struct persistent_ram_ecc_info ecc_info;
  87         unsigned int max_dump_cnt;
  88         unsigned int dump_write_cnt;
  89         /* _read_cnt need clear on ramoops_pstore_open */
  90         unsigned int dump_read_cnt;
  91         unsigned int console_read_cnt;
  92         unsigned int ftrace_read_cnt;
  93         struct pstore_info pstore;
  94 };
  95
  96 static struct platform_device *dummy;
  97 static struct ramoops_platform_data *dummy_data;
  98
  99 static int ramoops_pstore_open(struct pstore_info *psi)
 100 {
 101         struct ramoops_context *cxt = psi->data;
 102
 103         cxt->dump_read_cnt = 0;
 104         cxt->console_read_cnt = 0;
 105         cxt->ftrace_read_cnt = 0;
 106         return 0;
 107 }
 108
 109 static struct persistent_ram_zone *
 110 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 111                      u64 *id,
 112                      enum pstore_type_id *typep, enum pstore_type_id type,
 113                      bool update)
 114 {
 115         struct persistent_ram_zone *prz;
 116         int i = (*c)++;
 117
 118         if (i >= max)
 119                 return NULL;
 120
 121         prz = przs[i];
 122         if (!prz)
 123                 return NULL;
 124
 125         /* Update old/shadowed buffer. */
 126         if (update)
 127                 persistent_ram_save_old(prz);
 128
 129         if (!persistent_ram_old_size(prz))
 130                 return NULL;
 131
 132         *typep = type;
 133         *id = i;
 134
 135         return prz;
 136 }
 137
 138 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec *time,
 139                                   bool *compressed)
 140 {
 141         char data_type;
 142         int header_length = 0;
 143
 144         if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n%n", &time->tv_sec,
 145                         &time->tv_nsec, &data_type, &header_length) == 3) {
 146                 if (data_type == 'C')
 147                         *compressed = true;
 148                 else
 149                         *compressed = false;
 150         } else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu\n%n",
 151                         &time->tv_sec, &time->tv_nsec, &header_length) == 2) {
 152                         *compressed = false;
 153         } else {
 154                 time->tv_sec = 0;
 155                 time->tv_nsec = 0;
 156                 *compressed = false;
 157         }
 158         return header_length;
 159 }
 160
 161 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 162                                    int *count, struct timespec *time,
 163                                    char **buf, bool *compressed,
 164                                    struct pstore_info *psi)
 165 {
 166         ssize_t size;
 167         ssize_t ecc_notice_size;
 168         struct ramoops_context *cxt = psi->data;
 169         struct persistent_ram_zone *prz;
 170         int header_length;
 171
 172         prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
 173                                    cxt->max_dump_cnt, id, type,
 174                                    PSTORE_TYPE_DMESG, 1);
 175         if (!prz)
 176                 prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
 177                                            1, id, type, PSTORE_TYPE_CONSOLE, 0);
 178         if (!prz)
 179                 prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
 180                                            1, id, type, PSTORE_TYPE_FTRACE, 0);
 181         if (!prz)
 182                 return 0;
 183
 184         if (!persistent_ram_old(prz))
 185                 return 0;
 186
 187         size = persistent_ram_old_size(prz);
 188         header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz), time,
 189                         compressed);
 190         size -= header_length;
 191
 192         /* ECC correction notice */
 193         ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 194
 195         *buf = kmalloc(size + ecc_notice_size + 1, GFP_KERNEL);
 196         if (*buf == NULL)
 197                 return -ENOMEM;
 198
 199         memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
 200         persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);
 201
 202         return size + ecc_notice_size;
 203 }
 204
 205 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 206                                      bool compressed)
 207 {
 208         char *hdr;
 209         struct timespec timestamp;
 210         size_t len;
 211
 212         /* Report zeroed timestamp if called before timekeeping has resumed. */
 213         if (__getnstimeofday(&timestamp)) {
 214                 timestamp.tv_sec = 0;
 215                 timestamp.tv_nsec = 0;
 216         }
 217         hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
 218                 (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000),
 219                 compressed ? 'C' : 'D');
 220         WARN_ON_ONCE(!hdr);
 221         len = hdr ? strlen(hdr) : 0;
 222         persistent_ram_write(prz, hdr, len);
 223         kfree(hdr);
 224
 225         return len;
 226 }
 227
 228 static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 229                                             enum kmsg_dump_reason reason,
 230                                             u64 *id, unsigned int part,
 231                                             const char *buf,
 232                                             bool compressed, size_t size,
 233                                             struct pstore_info *psi)
 234 {
 235         struct ramoops_context *cxt = psi->data;
 236         struct persistent_ram_zone *prz;
 237         size_t hlen;
 238
 239         if (type == PSTORE_TYPE_CONSOLE) {
 240                 if (!cxt->cprz)
 241                         return -ENOMEM;
 242                 persistent_ram_write(cxt->cprz, buf, size);
 243                 return 0;
 244         } else if (type == PSTORE_TYPE_FTRACE) {
 245                 if (!cxt->fprz)
 246                         return -ENOMEM;
 247                 persistent_ram_write(cxt->fprz, buf, size);
 248                 return 0;
 249         }
 250
 251         if (type != PSTORE_TYPE_DMESG)
 252                 return -EINVAL;
 253
 254         /* Out of the various dmesg dump types, ramoops is currently designed
 255          * to only store crash logs, rather than storing general kernel logs.
 256          */
 257         if (reason != KMSG_DUMP_OOPS &&
 258             reason != KMSG_DUMP_PANIC)
 259                 return -EINVAL;
 260
 261         /* Skip Oopes when configured to do so. */
 262         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 263                 return -EINVAL;
 264
 265         /* Explicitly only take the first part of any new crash.
 266          * If our buffer is larger than kmsg_bytes, this can never happen,
 267          * and if our buffer is smaller than kmsg_bytes, we don't want the
 268          * report split across multiple records.
 269          */
 270         if (part != 1)
 271                 return -ENOSPC;
 272
 273         if (!cxt->przs)
 274                 return -ENOSPC;
 275
 276         prz = cxt->przs[cxt->dump_write_cnt];
 277
 278         hlen = ramoops_write_kmsg_hdr(prz, compressed);
 279         if (size + hlen > prz->buffer_size)
 280                 size = prz->buffer_size - hlen;
 281         persistent_ram_write(prz, buf, size);
 282
 283         cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 284
 285         return 0;
 286 }
 287
 288 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
 289                                 struct timespec time, struct pstore_info *psi)
 290 {
 291         struct ramoops_context *cxt = psi->data;
 292         struct persistent_ram_zone *prz;
 293
 294         switch (type) {
 295         case PSTORE_TYPE_DMESG:
 296                 if (id >= cxt->max_dump_cnt)
 297                         return -EINVAL;
 298                 prz = cxt->przs[id];
 299                 break;
 300         case PSTORE_TYPE_CONSOLE:
 301                 prz = cxt->cprz;
 302                 break;
 303         case PSTORE_TYPE_FTRACE:
 304                 prz = cxt->fprz;
 305                 break;
 306         default:
 307                 return -EINVAL;
 308         }
 309
 310         persistent_ram_free_old(prz);
 311         persistent_ram_zap(prz);
 312
 313         return 0;
 314 }
 315
 316 static struct ramoops_context oops_cxt = {
 317         .pstore = {
 318                 .owner  = THIS_MODULE,
 319                 .name   = "ramoops",
 320                 .open   = ramoops_pstore_open,
 321                 .read   = ramoops_pstore_read,
 322                 .write_buf      = ramoops_pstore_write_buf,
 323                 .erase  = ramoops_pstore_erase,
 324         },
 325 };
 326
 327 static void ramoops_free_przs(struct ramoops_context *cxt)
 328 {
 329         int i;
 330
 331         cxt->max_dump_cnt = 0;
 332         if (!cxt->przs)
 333                 return;
 334
 335         for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
 336                 persistent_ram_free(cxt->przs[i]);
 337         kfree(cxt->przs);
 338 }
 339
 340 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 341                              phys_addr_t *paddr, size_t dump_mem_sz)
 342 {
 343         int err = -ENOMEM;
 344         int i;
 345
 346         if (!cxt->record_size)
 347                 return 0;
 348
 349         if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
 350                 dev_err(dev, "no room for dumps\n");
 351                 return -ENOMEM;
 352         }
 353
 354         cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
 355         if (!cxt->max_dump_cnt)
 356                 return -ENOMEM;
 357
 358         cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
 359                              GFP_KERNEL);
 360         if (!cxt->przs) {
 361                 dev_err(dev, "failed to initialize a prz array for dumps\n");
 362                 goto fail_prz;
 363         }
 364
 365         for (i = 0; i < cxt->max_dump_cnt; i++) {
 366                 size_t sz = cxt->record_size;
 367
 368                 cxt->przs[i] = persistent_ram_new(*paddr, sz, 0,
 369                                                   &cxt->ecc_info);
 370                 if (IS_ERR(cxt->przs[i])) {
 371                         err = PTR_ERR(cxt->przs[i]);
 372                         dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 373                                 sz, (unsigned long long)*paddr, err);
 374                         goto fail_prz;
 375                 }
 376                 *paddr += sz;
 377         }
 378
 379         return 0;
 380 fail_prz:
 381         ramoops_free_przs(cxt);
 382         return err;
 383 }
 384
 385 static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 386                             struct persistent_ram_zone **prz,
 387                             phys_addr_t *paddr, size_t sz, u32 sig)
 388 {
 389         if (!sz)
 390                 return 0;
 391
 392         if (*paddr + sz - cxt->phys_addr > cxt->size) {
 393                 dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 394                         sz, (unsigned long long)*paddr,
 395                         cxt->size, (unsigned long long)cxt->phys_addr);
 396                 return -ENOMEM;
 397         }
 398
 399         *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info);
 400         if (IS_ERR(*prz)) {
 401                 int err = PTR_ERR(*prz);
 402
 403                 dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 404                         sz, (unsigned long long)*paddr, err);
 405                 return err;
 406         }
 407
 408         persistent_ram_zap(*prz);
 409
 410         *paddr += sz;
 411
 412         return 0;
 413 }
 414
 415 static int ramoops_probe(struct platform_device *pdev)
 416 {
 417         struct device *dev = &pdev->dev;
 418         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 419         struct ramoops_context *cxt = &oops_cxt;
 420         size_t dump_mem_sz;
 421         phys_addr_t paddr;
 422         int err = -EINVAL;
 423
 424         /* Only a single ramoops area allowed at a time, so fail extra
 425          * probes.
 426          */
 427         if (cxt->max_dump_cnt)
 428                 goto fail_out;
 429
 430         if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 431                         !pdata->ftrace_size)) {
 432                 pr_err("The memory size and the record/console size must be "
 433                         "non-zero\n");
 434                 goto fail_out;
 435         }
 436
 437         if (pdata->record_size && !is_power_of_2(pdata->record_size))
 438                 pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 439         if (pdata->console_size && !is_power_of_2(pdata->console_size))
 440                 pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 441         if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
 442                 pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 443
 444         cxt->size = pdata->mem_size;
 445         cxt->phys_addr = pdata->mem_address;
 446         cxt->record_size = pdata->record_size;
 447         cxt->console_size = pdata->console_size;
 448         cxt->ftrace_size = pdata->ftrace_size;
 449         cxt->dump_oops = pdata->dump_oops;
 450         cxt->ecc_info = pdata->ecc_info;
 451
 452         paddr = cxt->phys_addr;
 453
 454         dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
 455         err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 456         if (err)
 457                 goto fail_out;
 458
 459         err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
 460                                cxt->console_size, 0);
 461         if (err)
 462                 goto fail_init_cprz;
 463
 464         err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
 465                                LINUX_VERSION_CODE);
 466         if (err)
 467                 goto fail_init_fprz;
 468
 469         if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
 470                 pr_err("memory size too small, minimum is %zu\n",
 471                         cxt->console_size + cxt->record_size +
 472                         cxt->ftrace_size);
 473                 err = -EINVAL;
 474                 goto fail_cnt;
 475         }
 476
 477         cxt->pstore.data = cxt;
 478         /*
 479          * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
 480          * have to handle dumps, we must have at least record_size buffer. And
 481          * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
 482          * ZERO_SIZE_PTR).
 483          */
 484         if (cxt->console_size)
 485                 cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
 486         cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
 487         cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 488         spin_lock_init(&cxt->pstore.buf_lock);
 489         if (!cxt->pstore.buf) {
 490                 pr_err("cannot allocate pstore buffer\n");
 491                 err = -ENOMEM;
 492                 goto fail_clear;
 493         }
 494
 495         err = pstore_register(&cxt->pstore);
 496         if (err) {
 497                 pr_err("registering with pstore failed\n");
 498                 goto fail_buf;
 499         }
 500
 501         /*
 502          * Update the module parameter variables as well so they are visible
 503          * through /sys/module/ramoops/parameters/
 504          */
 505         mem_size = pdata->mem_size;
 506         mem_address = pdata->mem_address;
 507         record_size = pdata->record_size;
 508         dump_oops = pdata->dump_oops;
 509
 510         pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
 511                 cxt->size, (unsigned long long)cxt->phys_addr,
 512                 cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
 513
 514         return 0;
 515
 516 fail_buf:
 517         kfree(cxt->pstore.buf);
 518 fail_clear:
 519         cxt->pstore.bufsize = 0;
 520 fail_cnt:
 521         kfree(cxt->fprz);
 522 fail_init_fprz:
 523         kfree(cxt->cprz);
 524 fail_init_cprz:
 525         ramoops_free_przs(cxt);
 526 fail_out:
 527         return err;
 528 }
 529
 530 static int __exit ramoops_remove(struct platform_device *pdev)
 531 {
 532 #if 0
 533         /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 534          * unregistering yet.
 535          */
 536         struct ramoops_context *cxt = &oops_cxt;
 537
 538         iounmap(cxt->virt_addr);
 539         release_mem_region(cxt->phys_addr, cxt->size);
 540         cxt->max_dump_cnt = 0;
 541
 542         /* TODO(kees): When pstore supports unregistering, call it here. */
 543         kfree(cxt->pstore.buf);
 544         cxt->pstore.bufsize = 0;
 545
 546         return 0;
 547 #endif
 548         return -EBUSY;
 549 }
 550
 551 static struct platform_driver ramoops_driver = {
 552         .probe          = ramoops_probe,
 553         .remove         = __exit_p(ramoops_remove),
 554         .driver         = {
 555                 .name   = "ramoops",
 556                 .owner  = THIS_MODULE,
 557         },
 558 };
 559
 560 static void ramoops_register_dummy(void)
 561 {
 562         if (!mem_size)
 563                 return;
 564
 565         pr_info("using module parameters\n");
 566
 567         dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 568         if (!dummy_data) {
 569                 pr_info("could not allocate pdata\n");
 570                 return;
 571         }
 572
 573         dummy_data->mem_size = mem_size;
 574         dummy_data->mem_address = mem_address;
 575         dummy_data->record_size = record_size;
 576         dummy_data->console_size = ramoops_console_size;
 577         dummy_data->ftrace_size = ramoops_ftrace_size;
 578         dummy_data->dump_oops = dump_oops;
 579         /*
 580          * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 581          * (using 1 byte for ECC isn't much of use anyway).
 582          */
 583         dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 584
 585         dummy = platform_device_register_data(NULL, "ramoops", -1,
 586                         dummy_data, sizeof(struct ramoops_platform_data));
 587         if (IS_ERR(dummy)) {
 588                 pr_info("could not create platform device: %ld\n",
 589                         PTR_ERR(dummy));
 590         }
 591 }
 592
 593 static int __init ramoops_init(void)
 594 {
 595         ramoops_register_dummy();
 596         return platform_driver_register(&ramoops_driver);
 597 }
 598 postcore_initcall(ramoops_init);
 599
 600 static void __exit ramoops_exit(void)
 601 {
 602         platform_driver_unregister(&ramoops_driver);
 603         platform_device_unregister(dummy);
 604         kfree(dummy_data);
 605 }
 606 module_exit(ramoops_exit);
 607
 608 MODULE_LICENSE("GPL");
 609 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 610 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");