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