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