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 unsigned int mem_type;
  65 module_param(mem_type, uint, 0600);
  66 MODULE_PARM_DESC(mem_type,
  67                 "set to 1 to try to use unbuffered memory (default 0)");
  68
  69 static int dump_oops = 1;
  70 module_param(dump_oops, int, 0600);
  71 MODULE_PARM_DESC(dump_oops,
  72                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  73
  74 static int ramoops_ecc;
  75 module_param_named(ecc, ramoops_ecc, int, 0600);
  76 MODULE_PARM_DESC(ramoops_ecc,
  77                 "if non-zero, the option enables ECC support and specifies "
  78                 "ECC buffer size in bytes (1 is a special value, means 16 "
  79                 "bytes ECC)");
  80
  81 struct ramoops_context {
  82         struct persistent_ram_zone **przs;
  83         struct persistent_ram_zone *cprz;
  84         struct persistent_ram_zone *fprz;
  85         phys_addr_t phys_addr;
  86         unsigned long size;
  87         unsigned int memtype;
  88         size_t record_size;
  89         size_t console_size;
  90         size_t ftrace_size;
  91         int dump_oops;
  92         struct persistent_ram_ecc_info ecc_info;
  93         unsigned int max_dump_cnt;
  94         unsigned int dump_write_cnt;
  95         /* _read_cnt need clear on ramoops_pstore_open */
  96         unsigned int dump_read_cnt;
  97         unsigned int console_read_cnt;
  98         unsigned int ftrace_read_cnt;
  99         struct pstore_info pstore;
 100 };
 101
 102 static struct platform_device *dummy;
 103 static struct ramoops_platform_data *dummy_data;
 104
 105 static int ramoops_pstore_open(struct pstore_info *psi)
 106 {
 107         struct ramoops_context *cxt = psi->data;
 108
 109         cxt->dump_read_cnt = 0;
 110         cxt->console_read_cnt = 0;
 111         cxt->ftrace_read_cnt = 0;
 112         return 0;
 113 }
 114
 115 static struct persistent_ram_zone *
 116 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 117                      u64 *id,
 118                      enum pstore_type_id *typep, enum pstore_type_id type,
 119                      bool update)
 120 {
 121         struct persistent_ram_zone *prz;
 122         int i = (*c)++;
 123
 124         if (i >= max)
 125                 return NULL;
 126
 127         prz = przs[i];
 128         if (!prz)
 129                 return NULL;
 130
 131         /* Update old/shadowed buffer. */
 132         if (update)
 133                 persistent_ram_save_old(prz);
 134
 135         if (!persistent_ram_old_size(prz))
 136                 return NULL;
 137
 138         *typep = type;
 139         *id = i;
 140
 141         return prz;
 142 }
 143
 144 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec *time,
 145                                   bool *compressed)
 146 {
 147         char data_type;
 148         int header_length = 0;
 149
 150         if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n%n", &time->tv_sec,
 151                         &time->tv_nsec, &data_type, &header_length) == 3) {
 152                 if (data_type == 'C')
 153                         *compressed = true;
 154                 else
 155                         *compressed = false;
 156         } else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu\n%n",
 157                         &time->tv_sec, &time->tv_nsec, &header_length) == 2) {
 158                         *compressed = false;
 159         } else {
 160                 time->tv_sec = 0;
 161                 time->tv_nsec = 0;
 162                 *compressed = false;
 163         }
 164         return header_length;
 165 }
 166
 167 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 168                                    int *count, struct timespec *time,
 169                                    char **buf, bool *compressed,
 170                                    struct pstore_info *psi)
 171 {
 172         ssize_t size;
 173         ssize_t ecc_notice_size;
 174         struct ramoops_context *cxt = psi->data;
 175         struct persistent_ram_zone *prz;
 176         int header_length;
 177
 178         prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
 179                                    cxt->max_dump_cnt, id, type,
 180                                    PSTORE_TYPE_DMESG, 1);
 181         if (!prz)
 182                 prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
 183                                            1, id, type, PSTORE_TYPE_CONSOLE, 0);
 184         if (!prz)
 185                 prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
 186                                            1, id, type, PSTORE_TYPE_FTRACE, 0);
 187         if (!prz)
 188                 return 0;
 189
 190         if (!persistent_ram_old(prz))
 191                 return 0;
 192
 193         size = persistent_ram_old_size(prz);
 194         header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz), time,
 195                         compressed);
 196         size -= header_length;
 197
 198         /* ECC correction notice */
 199         ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 200
 201         *buf = kmalloc(size + ecc_notice_size + 1, GFP_KERNEL);
 202         if (*buf == NULL)
 203                 return -ENOMEM;
 204
 205         memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
 206         persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);
 207
 208         return size + ecc_notice_size;
 209 }
 210
 211 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 212                                      bool compressed)
 213 {
 214         char *hdr;
 215         struct timespec timestamp;
 216         size_t len;
 217
 218         /* Report zeroed timestamp if called before timekeeping has resumed. */
 219         if (__getnstimeofday(&timestamp)) {
 220                 timestamp.tv_sec = 0;
 221                 timestamp.tv_nsec = 0;
 222         }
 223         hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
 224                 (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000),
 225                 compressed ? 'C' : 'D');
 226         WARN_ON_ONCE(!hdr);
 227         len = hdr ? strlen(hdr) : 0;
 228         persistent_ram_write(prz, hdr, len);
 229         kfree(hdr);
 230
 231         return len;
 232 }
 233
 234 static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 235                                             enum kmsg_dump_reason reason,
 236                                             u64 *id, unsigned int part,
 237                                             const char *buf,
 238                                             bool compressed, size_t size,
 239                                             struct pstore_info *psi)
 240 {
 241         struct ramoops_context *cxt = psi->data;
 242         struct persistent_ram_zone *prz;
 243         size_t hlen;
 244
 245         if (type == PSTORE_TYPE_CONSOLE) {
 246                 if (!cxt->cprz)
 247                         return -ENOMEM;
 248                 persistent_ram_write(cxt->cprz, buf, size);
 249                 return 0;
 250         } else if (type == PSTORE_TYPE_FTRACE) {
 251                 if (!cxt->fprz)
 252                         return -ENOMEM;
 253                 persistent_ram_write(cxt->fprz, buf, size);
 254                 return 0;
 255         }
 256
 257         if (type != PSTORE_TYPE_DMESG)
 258                 return -EINVAL;
 259
 260         /* Out of the various dmesg dump types, ramoops is currently designed
 261          * to only store crash logs, rather than storing general kernel logs.
 262          */
 263         if (reason != KMSG_DUMP_OOPS &&
 264             reason != KMSG_DUMP_PANIC)
 265                 return -EINVAL;
 266
 267         /* Skip Oopes when configured to do so. */
 268         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 269                 return -EINVAL;
 270
 271         /* Explicitly only take the first part of any new crash.
 272          * If our buffer is larger than kmsg_bytes, this can never happen,
 273          * and if our buffer is smaller than kmsg_bytes, we don't want the
 274          * report split across multiple records.
 275          */
 276         if (part != 1)
 277                 return -ENOSPC;
 278
 279         if (!cxt->przs)
 280                 return -ENOSPC;
 281
 282         prz = cxt->przs[cxt->dump_write_cnt];
 283
 284         hlen = ramoops_write_kmsg_hdr(prz, compressed);
 285         if (size + hlen > prz->buffer_size)
 286                 size = prz->buffer_size - hlen;
 287         persistent_ram_write(prz, buf, size);
 288
 289         cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 290
 291         return 0;
 292 }
 293
 294 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
 295                                 struct timespec time, struct pstore_info *psi)
 296 {
 297         struct ramoops_context *cxt = psi->data;
 298         struct persistent_ram_zone *prz;
 299
 300         switch (type) {
 301         case PSTORE_TYPE_DMESG:
 302                 if (id >= cxt->max_dump_cnt)
 303                         return -EINVAL;
 304                 prz = cxt->przs[id];
 305                 break;
 306         case PSTORE_TYPE_CONSOLE:
 307                 prz = cxt->cprz;
 308                 break;
 309         case PSTORE_TYPE_FTRACE:
 310                 prz = cxt->fprz;
 311                 break;
 312         default:
 313                 return -EINVAL;
 314         }
 315
 316         persistent_ram_free_old(prz);
 317         persistent_ram_zap(prz);
 318
 319         return 0;
 320 }
 321
 322 static struct ramoops_context oops_cxt = {
 323         .pstore = {
 324                 .owner  = THIS_MODULE,
 325                 .name   = "ramoops",
 326                 .open   = ramoops_pstore_open,
 327                 .read   = ramoops_pstore_read,
 328                 .write_buf      = ramoops_pstore_write_buf,
 329                 .erase  = ramoops_pstore_erase,
 330         },
 331 };
 332
 333 static void ramoops_free_przs(struct ramoops_context *cxt)
 334 {
 335         int i;
 336
 337         cxt->max_dump_cnt = 0;
 338         if (!cxt->przs)
 339                 return;
 340
 341         for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
 342                 persistent_ram_free(cxt->przs[i]);
 343         kfree(cxt->przs);
 344 }
 345
 346 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 347                              phys_addr_t *paddr, size_t dump_mem_sz)
 348 {
 349         int err = -ENOMEM;
 350         int i;
 351
 352         if (!cxt->record_size)
 353                 return 0;
 354
 355         if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
 356                 dev_err(dev, "no room for dumps\n");
 357                 return -ENOMEM;
 358         }
 359
 360         cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
 361         if (!cxt->max_dump_cnt)
 362                 return -ENOMEM;
 363
 364         cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
 365                              GFP_KERNEL);
 366         if (!cxt->przs) {
 367                 dev_err(dev, "failed to initialize a prz array for dumps\n");
 368                 goto fail_prz;
 369         }
 370
 371         for (i = 0; i < cxt->max_dump_cnt; i++) {
 372                 size_t sz = cxt->record_size;
 373
 374                 cxt->przs[i] = persistent_ram_new(*paddr, sz, 0,
 375                                                   &cxt->ecc_info,
 376                                                   cxt->memtype);
 377                 if (IS_ERR(cxt->przs[i])) {
 378                         err = PTR_ERR(cxt->przs[i]);
 379                         dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 380                                 sz, (unsigned long long)*paddr, err);
 381                         goto fail_prz;
 382                 }
 383                 *paddr += sz;
 384         }
 385
 386         return 0;
 387 fail_prz:
 388         ramoops_free_przs(cxt);
 389         return err;
 390 }
 391
 392 static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 393                             struct persistent_ram_zone **prz,
 394                             phys_addr_t *paddr, size_t sz, u32 sig)
 395 {
 396         if (!sz)
 397                 return 0;
 398
 399         if (*paddr + sz - cxt->phys_addr > cxt->size) {
 400                 dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 401                         sz, (unsigned long long)*paddr,
 402                         cxt->size, (unsigned long long)cxt->phys_addr);
 403                 return -ENOMEM;
 404         }
 405
 406         *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, cxt->memtype);
 407         if (IS_ERR(*prz)) {
 408                 int err = PTR_ERR(*prz);
 409
 410                 dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 411                         sz, (unsigned long long)*paddr, err);
 412                 return err;
 413         }
 414
 415         persistent_ram_zap(*prz);
 416
 417         *paddr += sz;
 418
 419         return 0;
 420 }
 421
 422 static int ramoops_probe(struct platform_device *pdev)
 423 {
 424         struct device *dev = &pdev->dev;
 425         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 426         struct ramoops_context *cxt = &oops_cxt;
 427         size_t dump_mem_sz;
 428         phys_addr_t paddr;
 429         int err = -EINVAL;
 430
 431         /* Only a single ramoops area allowed at a time, so fail extra
 432          * probes.
 433          */
 434         if (cxt->max_dump_cnt)
 435                 goto fail_out;
 436
 437         if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 438                         !pdata->ftrace_size)) {
 439                 pr_err("The memory size and the record/console size must be "
 440                         "non-zero\n");
 441                 goto fail_out;
 442         }
 443
 444         if (pdata->record_size && !is_power_of_2(pdata->record_size))
 445                 pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 446         if (pdata->console_size && !is_power_of_2(pdata->console_size))
 447                 pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 448         if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
 449                 pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 450
 451         cxt->size = pdata->mem_size;
 452         cxt->phys_addr = pdata->mem_address;
 453         cxt->memtype = pdata->mem_type;
 454         cxt->record_size = pdata->record_size;
 455         cxt->console_size = pdata->console_size;
 456         cxt->ftrace_size = pdata->ftrace_size;
 457         cxt->dump_oops = pdata->dump_oops;
 458         cxt->ecc_info = pdata->ecc_info;
 459
 460         paddr = cxt->phys_addr;
 461
 462         dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
 463         err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 464         if (err)
 465                 goto fail_out;
 466
 467         err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
 468                                cxt->console_size, 0);
 469         if (err)
 470                 goto fail_init_cprz;
 471
 472         err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
 473                                LINUX_VERSION_CODE);
 474         if (err)
 475                 goto fail_init_fprz;
 476
 477         if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
 478                 pr_err("memory size too small, minimum is %zu\n",
 479                         cxt->console_size + cxt->record_size +
 480                         cxt->ftrace_size);
 481                 err = -EINVAL;
 482                 goto fail_cnt;
 483         }
 484
 485         cxt->pstore.data = cxt;
 486         /*
 487          * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
 488          * have to handle dumps, we must have at least record_size buffer. And
 489          * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
 490          * ZERO_SIZE_PTR).
 491          */
 492         if (cxt->console_size)
 493                 cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
 494         cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
 495         cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 496         spin_lock_init(&cxt->pstore.buf_lock);
 497         if (!cxt->pstore.buf) {
 498                 pr_err("cannot allocate pstore buffer\n");
 499                 err = -ENOMEM;
 500                 goto fail_clear;
 501         }
 502
 503         err = pstore_register(&cxt->pstore);
 504         if (err) {
 505                 pr_err("registering with pstore failed\n");
 506                 goto fail_buf;
 507         }
 508
 509         /*
 510          * Update the module parameter variables as well so they are visible
 511          * through /sys/module/ramoops/parameters/
 512          */
 513         mem_size = pdata->mem_size;
 514         mem_address = pdata->mem_address;
 515         record_size = pdata->record_size;
 516         dump_oops = pdata->dump_oops;
 517
 518         pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
 519                 cxt->size, (unsigned long long)cxt->phys_addr,
 520                 cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
 521
 522         return 0;
 523
 524 fail_buf:
 525         kfree(cxt->pstore.buf);
 526 fail_clear:
 527         cxt->pstore.bufsize = 0;
 528 fail_cnt:
 529         kfree(cxt->fprz);
 530 fail_init_fprz:
 531         kfree(cxt->cprz);
 532 fail_init_cprz:
 533         ramoops_free_przs(cxt);
 534 fail_out:
 535         return err;
 536 }
 537
 538 static int __exit ramoops_remove(struct platform_device *pdev)
 539 {
 540 #if 0
 541         /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 542          * unregistering yet.
 543          */
 544         struct ramoops_context *cxt = &oops_cxt;
 545
 546         iounmap(cxt->virt_addr);
 547         release_mem_region(cxt->phys_addr, cxt->size);
 548         cxt->max_dump_cnt = 0;
 549
 550         /* TODO(kees): When pstore supports unregistering, call it here. */
 551         kfree(cxt->pstore.buf);
 552         cxt->pstore.bufsize = 0;
 553
 554         return 0;
 555 #endif
 556         return -EBUSY;
 557 }
 558
 559 static struct platform_driver ramoops_driver = {
 560         .probe          = ramoops_probe,
 561         .remove         = __exit_p(ramoops_remove),
 562         .driver         = {
 563                 .name   = "ramoops",
 564                 .owner  = THIS_MODULE,
 565         },
 566 };
 567
 568 static void ramoops_register_dummy(void)
 569 {
 570         if (!mem_size)
 571                 return;
 572
 573         pr_info("using module parameters\n");
 574
 575         dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 576         if (!dummy_data) {
 577                 pr_info("could not allocate pdata\n");
 578                 return;
 579         }
 580
 581         dummy_data->mem_size = mem_size;
 582         dummy_data->mem_address = mem_address;
 583         dummy_data->mem_type = 0;
 584         dummy_data->record_size = record_size;
 585         dummy_data->console_size = ramoops_console_size;
 586         dummy_data->ftrace_size = ramoops_ftrace_size;
 587         dummy_data->dump_oops = dump_oops;
 588         /*
 589          * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 590          * (using 1 byte for ECC isn't much of use anyway).
 591          */
 592         dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 593
 594         dummy = platform_device_register_data(NULL, "ramoops", -1,
 595                         dummy_data, sizeof(struct ramoops_platform_data));
 596         if (IS_ERR(dummy)) {
 597                 pr_info("could not create platform device: %ld\n",
 598                         PTR_ERR(dummy));
 599         }
 600 }
 601
 602 static int __init ramoops_init(void)
 603 {
 604         ramoops_register_dummy();
 605         return platform_driver_register(&ramoops_driver);
 606 }
 607 postcore_initcall(ramoops_init);
 608
 609 static void __exit ramoops_exit(void)
 610 {
 611         platform_driver_unregister(&ramoops_driver);
 612         platform_device_unregister(dummy);
 613         kfree(dummy_data);
 614 }
 615 module_exit(ramoops_exit);
 616
 617 MODULE_LICENSE("GPL");
 618 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 619 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");