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