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