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