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 unsigned int mem_type;
  65 module_param(mem_type, uint, 0600);
  66 MODULE_PARM_DESC(mem_type,
  67                 "set to 1 to try to use unbuffered memory (default 0)");
  68
  69 static int dump_oops = 1;
  70 module_param(dump_oops, int, 0600);
  71 MODULE_PARM_DESC(dump_oops,
  72                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  73
  74 static int ramoops_ecc;
  75 module_param_named(ecc, ramoops_ecc, int, 0600);
  76 MODULE_PARM_DESC(ramoops_ecc,
  77                 "if non-zero, the option enables ECC support and specifies "
  78                 "ECC buffer size in bytes (1 is a special value, means 16 "
  79                 "bytes ECC)");
  80
  81 struct ramoops_context {
  82         struct persistent_ram_zone **przs;
  83         struct persistent_ram_zone *cprz;
  84         struct persistent_ram_zone *fprz;
  85         phys_addr_t phys_addr;
  86         unsigned long size;
  87         unsigned int memtype;
  88         size_t record_size;
  89         size_t console_size;
  90         size_t ftrace_size;
  91         int dump_oops;
  92         struct persistent_ram_ecc_info ecc_info;
  93         unsigned int max_dump_cnt;
  94         unsigned int dump_write_cnt;
  95         unsigned int dump_read_cnt;
  96         unsigned int console_read_cnt;
  97         unsigned int ftrace_read_cnt;
  98         struct pstore_info pstore;
  99 };
 100
 101 static struct platform_device *dummy;
 102 static struct ramoops_platform_data *dummy_data;
 103
 104 static int ramoops_pstore_open(struct pstore_info *psi)
 105 {
 106         struct ramoops_context *cxt = psi->data;
 107
 108         cxt->dump_read_cnt = 0;
 109         cxt->console_read_cnt = 0;
 110         return 0;
 111 }
 112
 113 static struct persistent_ram_zone *
 114 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 115                      u64 *id,
 116                      enum pstore_type_id *typep, enum pstore_type_id type,
 117                      bool update)
 118 {
 119         struct persistent_ram_zone *prz;
 120         int i = (*c)++;
 121
 122         if (i >= max)
 123                 return NULL;
 124
 125         prz = przs[i];
 126
 127         if (update) {
 128                 /* Update old/shadowed buffer. */
 129                 persistent_ram_save_old(prz);
 130                 if (!persistent_ram_old_size(prz))
 131                         return NULL;
 132         }
 133
 134         *typep = type;
 135         *id = i;
 136
 137         return prz;
 138 }
 139
 140 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 141                                    int *count, struct timespec *time,
 142                                    char **buf, struct pstore_info *psi)
 143 {
 144         ssize_t size;
 145         ssize_t ecc_notice_size;
 146         struct ramoops_context *cxt = psi->data;
 147         struct persistent_ram_zone *prz;
 148
 149         prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
 150                                    cxt->max_dump_cnt, id, type,
 151                                    PSTORE_TYPE_DMESG, 1);
 152         if (!prz)
 153                 prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
 154                                            1, id, type, PSTORE_TYPE_CONSOLE, 0);
 155         if (!prz)
 156                 prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
 157                                            1, id, type, PSTORE_TYPE_FTRACE, 0);
 158         if (!prz)
 159                 return 0;
 160
 161         /* TODO(kees): Bogus time for the moment. */
 162         time->tv_sec = 0;
 163         time->tv_nsec = 0;
 164
 165         size = persistent_ram_old_size(prz);
 166
 167         /* ECC correction notice */
 168         ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 169
 170         *buf = kmalloc(size + ecc_notice_size + 1, GFP_KERNEL);
 171         if (*buf == NULL)
 172                 return -ENOMEM;
 173
 174         memcpy(*buf, persistent_ram_old(prz), size);
 175         persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);
 176
 177         return size + ecc_notice_size;
 178 }
 179
 180 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 181 {
 182         char *hdr;
 183         struct timespec timestamp;
 184         size_t len;
 185
 186         /* Report zeroed timestamp if called before timekeeping has resumed. */
 187         if (__getnstimeofday(&timestamp)) {
 188                 timestamp.tv_sec = 0;
 189                 timestamp.tv_nsec = 0;
 190         }
 191         hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
 192                 (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000));
 193         WARN_ON_ONCE(!hdr);
 194         len = hdr ? strlen(hdr) : 0;
 195         persistent_ram_write(prz, hdr, len);
 196         kfree(hdr);
 197
 198         return len;
 199 }
 200
 201 static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 202                                             enum kmsg_dump_reason reason,
 203                                             u64 *id, unsigned int part,
 204                                             const char *buf, size_t size,
 205                                             struct pstore_info *psi)
 206 {
 207         struct ramoops_context *cxt = psi->data;
 208         struct persistent_ram_zone *prz;
 209         size_t hlen;
 210
 211         if (type == PSTORE_TYPE_CONSOLE) {
 212                 if (!cxt->cprz)
 213                         return -ENOMEM;
 214                 persistent_ram_write(cxt->cprz, buf, size);
 215                 return 0;
 216         } else if (type == PSTORE_TYPE_FTRACE) {
 217                 if (!cxt->fprz)
 218                         return -ENOMEM;
 219                 persistent_ram_write(cxt->fprz, buf, size);
 220                 return 0;
 221         }
 222
 223         if (type != PSTORE_TYPE_DMESG)
 224                 return -EINVAL;
 225
 226         /* Out of the various dmesg dump types, ramoops is currently designed
 227          * to only store crash logs, rather than storing general kernel logs.
 228          */
 229         if (reason != KMSG_DUMP_OOPS &&
 230             reason != KMSG_DUMP_PANIC)
 231                 return -EINVAL;
 232
 233         /* Skip Oopes when configured to do so. */
 234         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 235                 return -EINVAL;
 236
 237         /* Explicitly only take the first part of any new crash.
 238          * If our buffer is larger than kmsg_bytes, this can never happen,
 239          * and if our buffer is smaller than kmsg_bytes, we don't want the
 240          * report split across multiple records.
 241          */
 242         if (part != 1)
 243                 return -ENOSPC;
 244
 245         if (!cxt->przs)
 246                 return -ENOSPC;
 247
 248         prz = cxt->przs[cxt->dump_write_cnt];
 249
 250         hlen = ramoops_write_kmsg_hdr(prz);
 251         if (size + hlen > prz->buffer_size)
 252                 size = prz->buffer_size - hlen;
 253         persistent_ram_write(prz, buf, size);
 254
 255         cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 256
 257         return 0;
 258 }
 259
 260 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
 261                                 struct timespec time, struct pstore_info *psi)
 262 {
 263         struct ramoops_context *cxt = psi->data;
 264         struct persistent_ram_zone *prz;
 265
 266         switch (type) {
 267         case PSTORE_TYPE_DMESG:
 268                 if (id >= cxt->max_dump_cnt)
 269                         return -EINVAL;
 270                 prz = cxt->przs[id];
 271                 break;
 272         case PSTORE_TYPE_CONSOLE:
 273                 prz = cxt->cprz;
 274                 break;
 275         case PSTORE_TYPE_FTRACE:
 276                 prz = cxt->fprz;
 277                 break;
 278         default:
 279                 return -EINVAL;
 280         }
 281
 282         persistent_ram_free_old(prz);
 283         persistent_ram_zap(prz);
 284
 285         return 0;
 286 }
 287
 288 static struct ramoops_context oops_cxt = {
 289         .pstore = {
 290                 .owner  = THIS_MODULE,
 291                 .name   = "ramoops",
 292                 .open   = ramoops_pstore_open,
 293                 .read   = ramoops_pstore_read,
 294                 .write_buf      = ramoops_pstore_write_buf,
 295                 .erase  = ramoops_pstore_erase,
 296         },
 297 };
 298
 299 static void ramoops_free_przs(struct ramoops_context *cxt)
 300 {
 301         int i;
 302
 303         if (!cxt->przs)
 304                 return;
 305
 306         for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
 307                 persistent_ram_free(cxt->przs[i]);
 308         kfree(cxt->przs);
 309 }
 310
 311 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 312                              phys_addr_t *paddr, size_t dump_mem_sz)
 313 {
 314         int err = -ENOMEM;
 315         int i;
 316
 317         if (!cxt->record_size)
 318                 return 0;
 319
 320         if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
 321                 dev_err(dev, "no room for dumps\n");
 322                 return -ENOMEM;
 323         }
 324
 325         cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
 326         if (!cxt->max_dump_cnt)
 327                 return -ENOMEM;
 328
 329         cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
 330                              GFP_KERNEL);
 331         if (!cxt->przs) {
 332                 dev_err(dev, "failed to initialize a prz array for dumps\n");
 333                 return -ENOMEM;
 334         }
 335
 336         for (i = 0; i < cxt->max_dump_cnt; i++) {
 337                 size_t sz = cxt->record_size;
 338
 339                 cxt->przs[i] = persistent_ram_new(*paddr, sz, 0,
 340                                                   &cxt->ecc_info,
 341                                                   cxt->memtype);
 342                 if (IS_ERR(cxt->przs[i])) {
 343                         err = PTR_ERR(cxt->przs[i]);
 344                         dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 345                                 sz, (unsigned long long)*paddr, err);
 346                         goto fail_prz;
 347                 }
 348                 *paddr += sz;
 349         }
 350
 351         return 0;
 352 fail_prz:
 353         ramoops_free_przs(cxt);
 354         return err;
 355 }
 356
 357 static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 358                             struct persistent_ram_zone **prz,
 359                             phys_addr_t *paddr, size_t sz, u32 sig)
 360 {
 361         if (!sz)
 362                 return 0;
 363
 364         if (*paddr + sz - cxt->phys_addr > cxt->size) {
 365                 dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 366                         sz, (unsigned long long)*paddr,
 367                         cxt->size, (unsigned long long)cxt->phys_addr);
 368                 return -ENOMEM;
 369         }
 370
 371         *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, cxt->memtype);
 372         if (IS_ERR(*prz)) {
 373                 int err = PTR_ERR(*prz);
 374
 375                 dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 376                         sz, (unsigned long long)*paddr, err);
 377                 return err;
 378         }
 379
 380         persistent_ram_zap(*prz);
 381
 382         *paddr += sz;
 383
 384         return 0;
 385 }
 386
 387 static int ramoops_probe(struct platform_device *pdev)
 388 {
 389         struct device *dev = &pdev->dev;
 390         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 391         struct ramoops_context *cxt = &oops_cxt;
 392         size_t dump_mem_sz;
 393         phys_addr_t paddr;
 394         int err = -EINVAL;
 395
 396         /* Only a single ramoops area allowed at a time, so fail extra
 397          * probes.
 398          */
 399         if (cxt->max_dump_cnt)
 400                 goto fail_out;
 401
 402         if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 403                         !pdata->ftrace_size)) {
 404                 pr_err("The memory size and the record/console size must be "
 405                         "non-zero\n");
 406                 goto fail_out;
 407         }
 408
 409         if (!is_power_of_2(pdata->mem_size))
 410                 pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 411         if (!is_power_of_2(pdata->record_size))
 412                 pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 413         if (!is_power_of_2(pdata->console_size))
 414                 pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 415         if (!is_power_of_2(pdata->ftrace_size))
 416                 pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 417
 418         cxt->dump_read_cnt = 0;
 419         cxt->size = pdata->mem_size;
 420         cxt->phys_addr = pdata->mem_address;
 421         cxt->memtype = pdata->mem_type;
 422         cxt->record_size = pdata->record_size;
 423         cxt->console_size = pdata->console_size;
 424         cxt->ftrace_size = pdata->ftrace_size;
 425         cxt->dump_oops = pdata->dump_oops;
 426         cxt->ecc_info = pdata->ecc_info;
 427
 428         paddr = cxt->phys_addr;
 429
 430         dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
 431         err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 432         if (err)
 433                 goto fail_out;
 434
 435         err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
 436                                cxt->console_size, 0);
 437         if (err)
 438                 goto fail_init_cprz;
 439
 440         err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
 441                                LINUX_VERSION_CODE);
 442         if (err)
 443                 goto fail_init_fprz;
 444
 445         if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
 446                 pr_err("memory size too small, minimum is %zu\n",
 447                         cxt->console_size + cxt->record_size +
 448                         cxt->ftrace_size);
 449                 err = -EINVAL;
 450                 goto fail_cnt;
 451         }
 452
 453         cxt->pstore.data = cxt;
 454         /*
 455          * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
 456          * have to handle dumps, we must have at least record_size buffer. And
 457          * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
 458          * ZERO_SIZE_PTR).
 459          */
 460         if (cxt->console_size)
 461                 cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
 462         cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
 463         cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 464         spin_lock_init(&cxt->pstore.buf_lock);
 465         if (!cxt->pstore.buf) {
 466                 pr_err("cannot allocate pstore buffer\n");
 467                 err = -ENOMEM;
 468                 goto fail_clear;
 469         }
 470
 471         err = pstore_register(&cxt->pstore);
 472         if (err) {
 473                 pr_err("registering with pstore failed\n");
 474                 goto fail_buf;
 475         }
 476
 477         /*
 478          * Update the module parameter variables as well so they are visible
 479          * through /sys/module/ramoops/parameters/
 480          */
 481         mem_size = pdata->mem_size;
 482         mem_address = pdata->mem_address;
 483         record_size = pdata->record_size;
 484         dump_oops = pdata->dump_oops;
 485
 486         pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
 487                 cxt->size, (unsigned long long)cxt->phys_addr,
 488                 cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
 489
 490         return 0;
 491
 492 fail_buf:
 493         kfree(cxt->pstore.buf);
 494 fail_clear:
 495         cxt->pstore.bufsize = 0;
 496         cxt->max_dump_cnt = 0;
 497 fail_cnt:
 498         kfree(cxt->fprz);
 499 fail_init_fprz:
 500         kfree(cxt->cprz);
 501 fail_init_cprz:
 502         ramoops_free_przs(cxt);
 503 fail_out:
 504         return err;
 505 }
 506
 507 static int __exit ramoops_remove(struct platform_device *pdev)
 508 {
 509 #if 0
 510         /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 511          * unregistering yet.
 512          */
 513         struct ramoops_context *cxt = &oops_cxt;
 514
 515         iounmap(cxt->virt_addr);
 516         release_mem_region(cxt->phys_addr, cxt->size);
 517         cxt->max_dump_cnt = 0;
 518
 519         /* TODO(kees): When pstore supports unregistering, call it here. */
 520         kfree(cxt->pstore.buf);
 521         cxt->pstore.bufsize = 0;
 522
 523         return 0;
 524 #endif
 525         return -EBUSY;
 526 }
 527
 528 static struct platform_driver ramoops_driver = {
 529         .probe          = ramoops_probe,
 530         .remove         = __exit_p(ramoops_remove),
 531         .driver         = {
 532                 .name   = "ramoops",
 533                 .owner  = THIS_MODULE,
 534         },
 535 };
 536
 537 static void ramoops_register_dummy(void)
 538 {
 539         if (!mem_size)
 540                 return;
 541
 542         pr_info("using module parameters\n");
 543
 544         dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 545         if (!dummy_data) {
 546                 pr_info("could not allocate pdata\n");
 547                 return;
 548         }
 549
 550         dummy_data->mem_size = mem_size;
 551         dummy_data->mem_address = mem_address;
 552         dummy_data->mem_type = 0;
 553         dummy_data->record_size = record_size;
 554         dummy_data->console_size = ramoops_console_size;
 555         dummy_data->ftrace_size = ramoops_ftrace_size;
 556         dummy_data->dump_oops = dump_oops;
 557         /*
 558          * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 559          * (using 1 byte for ECC isn't much of use anyway).
 560          */
 561         dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 562
 563         dummy = platform_device_register_data(NULL, "ramoops", -1,
 564                         dummy_data, sizeof(struct ramoops_platform_data));
 565         if (IS_ERR(dummy)) {
 566                 pr_info("could not create platform device: %ld\n",
 567                         PTR_ERR(dummy));
 568         }
 569 }
 570
 571 static int __init ramoops_init(void)
 572 {
 573         ramoops_register_dummy();
 574         return platform_driver_register(&ramoops_driver);
 575 }
 576 postcore_initcall(ramoops_init);
 577
 578 static void __exit ramoops_exit(void)
 579 {
 580         platform_driver_unregister(&ramoops_driver);
 581         platform_device_unregister(dummy);
 582         kfree(dummy_data);
 583 }
 584 module_exit(ramoops_exit);
 585
 586 MODULE_LICENSE("GPL");
 587 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 588 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");