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