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/pstore_ram.h>
  36
  37 #define RAMOOPS_KERNMSG_HDR "===="
  38 #define MIN_MEM_SIZE 4096UL
  39
  40 static ulong record_size = MIN_MEM_SIZE;
  41 module_param(record_size, ulong, 0400);
  42 MODULE_PARM_DESC(record_size,
  43                 "size of each dump done on oops/panic");
  44
  45 static ulong ramoops_console_size = MIN_MEM_SIZE;
  46 module_param_named(console_size, ramoops_console_size, ulong, 0400);
  47 MODULE_PARM_DESC(console_size, "size of kernel console log");
  48
  49 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  50 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  51 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  52
  53 static ulong mem_address;
  54 module_param(mem_address, ulong, 0400);
  55 MODULE_PARM_DESC(mem_address,
  56                 "start of reserved RAM used to store oops/panic logs");
  57
  58 static ulong mem_size;
  59 module_param(mem_size, ulong, 0400);
  60 MODULE_PARM_DESC(mem_size,
  61                 "size of reserved RAM used to store oops/panic logs");
  62
  63 static int dump_oops = 1;
  64 module_param(dump_oops, int, 0600);
  65 MODULE_PARM_DESC(dump_oops,
  66                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  67
  68 static int ramoops_ecc;
  69 module_param_named(ecc, ramoops_ecc, int, 0600);
  70 MODULE_PARM_DESC(ramoops_ecc,
  71                 "if non-zero, the option enables ECC support and specifies "
  72                 "ECC buffer size in bytes (1 is a special value, means 16 "
  73                 "bytes ECC)");
  74
  75 struct ramoops_context {
  76         struct persistent_ram_zone **przs;
  77         struct persistent_ram_zone *cprz;
  78         struct persistent_ram_zone *fprz;
  79         phys_addr_t phys_addr;
  80         unsigned long size;
  81         size_t record_size;
  82         size_t console_size;
  83         size_t ftrace_size;
  84         int dump_oops;
  85         int ecc_size;
  86         unsigned int max_dump_cnt;
  87         unsigned int dump_write_cnt;
  88         unsigned int dump_read_cnt;
  89         unsigned int console_read_cnt;
  90         unsigned int ftrace_read_cnt;
  91         struct pstore_info pstore;
  92 };
  93
  94 static struct platform_device *dummy;
  95 static struct ramoops_platform_data *dummy_data;
  96
  97 static int ramoops_pstore_open(struct pstore_info *psi)
  98 {
  99         struct ramoops_context *cxt = psi->data;
 100
 101         cxt->dump_read_cnt = 0;
 102         cxt->console_read_cnt = 0;
 103         return 0;
 104 }
 105
 106 static struct persistent_ram_zone *
 107 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 108                      u64 *id,
 109                      enum pstore_type_id *typep, enum pstore_type_id type,
 110                      bool update)
 111 {
 112         struct persistent_ram_zone *prz;
 113         int i = (*c)++;
 114
 115         if (i >= max)
 116                 return NULL;
 117
 118         prz = przs[i];
 119
 120         if (update) {
 121                 /* Update old/shadowed buffer. */
 122                 persistent_ram_save_old(prz);
 123                 if (!persistent_ram_old_size(prz))
 124                         return NULL;
 125         }
 126
 127         *typep = type;
 128         *id = i;
 129
 130         return prz;
 131 }
 132
 133 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 134                                    struct timespec *time,
 135                                    char **buf,
 136                                    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 = kmalloc(size, GFP_KERNEL);
 160         if (*buf == NULL)
 161                 return -ENOMEM;
 162         memcpy(*buf, persistent_ram_old(prz), size);
 163
 164         return size;
 165 }
 166
 167 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 168 {
 169         char *hdr;
 170         struct timeval timestamp;
 171         size_t len;
 172
 173         do_gettimeofday(&timestamp);
 174         hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
 175                 (long)timestamp.tv_sec, (long)timestamp.tv_usec);
 176         WARN_ON_ONCE(!hdr);
 177         len = hdr ? strlen(hdr) : 0;
 178         persistent_ram_write(prz, hdr, len);
 179         kfree(hdr);
 180
 181         return len;
 182 }
 183
 184
 185 static int ramoops_pstore_write_buf(enum pstore_type_id type,
 186                                     enum kmsg_dump_reason reason,
 187                                     u64 *id, unsigned int part,
 188                                     const char *buf, size_t size,
 189                                     struct pstore_info *psi)
 190 {
 191         struct ramoops_context *cxt = psi->data;
 192         struct persistent_ram_zone *prz = cxt->przs[cxt->dump_write_cnt];
 193         size_t hlen;
 194
 195         if (type == PSTORE_TYPE_CONSOLE) {
 196                 if (!cxt->cprz)
 197                         return -ENOMEM;
 198                 persistent_ram_write(cxt->cprz, buf, size);
 199                 return 0;
 200         } else if (type == PSTORE_TYPE_FTRACE) {
 201                 if (!cxt->fprz)
 202                         return -ENOMEM;
 203                 persistent_ram_write(cxt->fprz, buf, size);
 204                 return 0;
 205         }
 206
 207         if (type != PSTORE_TYPE_DMESG)
 208                 return -EINVAL;
 209
 210         /* Out of the various dmesg dump types, ramoops is currently designed
 211          * to only store crash logs, rather than storing general kernel logs.
 212          */
 213         if (reason != KMSG_DUMP_OOPS &&
 214             reason != KMSG_DUMP_PANIC)
 215                 return -EINVAL;
 216
 217         /* Skip Oopes when configured to do so. */
 218         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 219                 return -EINVAL;
 220
 221         /* Explicitly only take the first part of any new crash.
 222          * If our buffer is larger than kmsg_bytes, this can never happen,
 223          * and if our buffer is smaller than kmsg_bytes, we don't want the
 224          * report split across multiple records.
 225          */
 226         if (part != 1)
 227                 return -ENOSPC;
 228
 229         hlen = ramoops_write_kmsg_hdr(prz);
 230         if (size + hlen > prz->buffer_size)
 231                 size = prz->buffer_size - hlen;
 232         persistent_ram_write(prz, buf, size);
 233
 234         cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 235
 236         return 0;
 237 }
 238
 239 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
 240                                 struct pstore_info *psi)
 241 {
 242         struct ramoops_context *cxt = psi->data;
 243         struct persistent_ram_zone *prz;
 244
 245         switch (type) {
 246         case PSTORE_TYPE_DMESG:
 247                 if (id >= cxt->max_dump_cnt)
 248                         return -EINVAL;
 249                 prz = cxt->przs[id];
 250                 break;
 251         case PSTORE_TYPE_CONSOLE:
 252                 prz = cxt->cprz;
 253                 break;
 254         case PSTORE_TYPE_FTRACE:
 255                 prz = cxt->fprz;
 256                 break;
 257         default:
 258                 return -EINVAL;
 259         }
 260
 261         persistent_ram_free_old(prz);
 262         persistent_ram_zap(prz);
 263
 264         return 0;
 265 }
 266
 267 static struct ramoops_context oops_cxt = {
 268         .pstore = {
 269                 .owner  = THIS_MODULE,
 270                 .name   = "ramoops",
 271                 .open   = ramoops_pstore_open,
 272                 .read   = ramoops_pstore_read,
 273                 .write_buf      = ramoops_pstore_write_buf,
 274                 .erase  = ramoops_pstore_erase,
 275         },
 276 };
 277
 278 static void ramoops_free_przs(struct ramoops_context *cxt)
 279 {
 280         int i;
 281
 282         if (!cxt->przs)
 283                 return;
 284
 285         for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
 286                 persistent_ram_free(cxt->przs[i]);
 287         kfree(cxt->przs);
 288 }
 289
 290 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 291                               phys_addr_t *paddr, size_t dump_mem_sz)
 292 {
 293         int err = -ENOMEM;
 294         int i;
 295
 296         if (!cxt->record_size)
 297                 return 0;
 298
 299         cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
 300         if (!cxt->max_dump_cnt)
 301                 return -ENOMEM;
 302
 303         cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
 304                              GFP_KERNEL);
 305         if (!cxt->przs) {
 306                 dev_err(dev, "failed to initialize a prz array for dumps\n");
 307                 return -ENOMEM;
 308         }
 309
 310         for (i = 0; i < cxt->max_dump_cnt; i++) {
 311                 size_t sz = cxt->record_size;
 312
 313                 cxt->przs[i] = persistent_ram_new(*paddr, sz, 0, cxt->ecc_size);
 314                 if (IS_ERR(cxt->przs[i])) {
 315                         err = PTR_ERR(cxt->przs[i]);
 316                         dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 317                                 sz, (unsigned long long)*paddr, err);
 318                         goto fail_prz;
 319                 }
 320                 *paddr += sz;
 321         }
 322
 323         return 0;
 324 fail_prz:
 325         ramoops_free_przs(cxt);
 326         return err;
 327 }
 328
 329 static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 330                             struct persistent_ram_zone **prz,
 331                             phys_addr_t *paddr, size_t sz, u32 sig)
 332 {
 333         if (!sz)
 334                 return 0;
 335
 336         if (*paddr + sz > *paddr + cxt->size)
 337                 return -ENOMEM;
 338
 339         *prz = persistent_ram_new(*paddr, sz, sig, cxt->ecc_size);
 340         if (IS_ERR(*prz)) {
 341                 int err = PTR_ERR(*prz);
 342
 343                 dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 344                         sz, (unsigned long long)*paddr, err);
 345                 return err;
 346         }
 347
 348         persistent_ram_zap(*prz);
 349
 350         *paddr += sz;
 351
 352         return 0;
 353 }
 354
 355 static int __devinit ramoops_probe(struct platform_device *pdev)
 356 {
 357         struct device *dev = &pdev->dev;
 358         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 359         struct ramoops_context *cxt = &oops_cxt;
 360         size_t dump_mem_sz;
 361         phys_addr_t paddr;
 362         int err = -EINVAL;
 363
 364         /* Only a single ramoops area allowed at a time, so fail extra
 365          * probes.
 366          */
 367         if (cxt->max_dump_cnt)
 368                 goto fail_out;
 369
 370         if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 371                         !pdata->ftrace_size)) {
 372                 pr_err("The memory size and the record/console size must be "
 373                         "non-zero\n");
 374                 goto fail_out;
 375         }
 376
 377         pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 378         pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 379         pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 380         pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 381
 382         cxt->dump_read_cnt = 0;
 383         cxt->size = pdata->mem_size;
 384         cxt->phys_addr = pdata->mem_address;
 385         cxt->record_size = pdata->record_size;
 386         cxt->console_size = pdata->console_size;
 387         cxt->ftrace_size = pdata->ftrace_size;
 388         cxt->dump_oops = pdata->dump_oops;
 389         cxt->ecc_size = pdata->ecc_size;
 390
 391         paddr = cxt->phys_addr;
 392
 393         dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
 394         err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 395         if (err)
 396                 goto fail_out;
 397
 398         err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
 399                                cxt->console_size, 0);
 400         if (err)
 401                 goto fail_init_cprz;
 402
 403         err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
 404                                LINUX_VERSION_CODE);
 405         if (err)
 406                 goto fail_init_fprz;
 407
 408         if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
 409                 pr_err("memory size too small, minimum is %lu\n",
 410                         cxt->console_size + cxt->record_size +
 411                         cxt->ftrace_size);
 412                 goto fail_cnt;
 413         }
 414
 415         cxt->pstore.data = cxt;
 416         /*
 417          * Console can handle any buffer size, so prefer dumps buffer
 418          * size since usually it is smaller.
 419          */
 420         if (cxt->przs)
 421                 cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
 422         else
 423                 cxt->pstore.bufsize = cxt->cprz->buffer_size;
 424         cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 425         spin_lock_init(&cxt->pstore.buf_lock);
 426         if (!cxt->pstore.buf) {
 427                 pr_err("cannot allocate pstore buffer\n");
 428                 goto fail_clear;
 429         }
 430
 431         err = pstore_register(&cxt->pstore);
 432         if (err) {
 433                 pr_err("registering with pstore failed\n");
 434                 goto fail_buf;
 435         }
 436
 437         /*
 438          * Update the module parameter variables as well so they are visible
 439          * through /sys/module/ramoops/parameters/
 440          */
 441         mem_size = pdata->mem_size;
 442         mem_address = pdata->mem_address;
 443         record_size = pdata->record_size;
 444         dump_oops = pdata->dump_oops;
 445
 446         pr_info("attached 0x%lx@0x%llx, ecc: %d\n",
 447                 cxt->size, (unsigned long long)cxt->phys_addr,
 448                 cxt->ecc_size);
 449
 450         return 0;
 451
 452 fail_buf:
 453         kfree(cxt->pstore.buf);
 454 fail_clear:
 455         cxt->pstore.bufsize = 0;
 456         cxt->max_dump_cnt = 0;
 457 fail_cnt:
 458         kfree(cxt->fprz);
 459 fail_init_fprz:
 460         kfree(cxt->cprz);
 461 fail_init_cprz:
 462         ramoops_free_przs(cxt);
 463 fail_out:
 464         return err;
 465 }
 466
 467 static int __exit ramoops_remove(struct platform_device *pdev)
 468 {
 469 #if 0
 470         /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 471          * unregistering yet.
 472          */
 473         struct ramoops_context *cxt = &oops_cxt;
 474
 475         iounmap(cxt->virt_addr);
 476         release_mem_region(cxt->phys_addr, cxt->size);
 477         cxt->max_dump_cnt = 0;
 478
 479         /* TODO(kees): When pstore supports unregistering, call it here. */
 480         kfree(cxt->pstore.buf);
 481         cxt->pstore.bufsize = 0;
 482
 483         return 0;
 484 #endif
 485         return -EBUSY;
 486 }
 487
 488 static struct platform_driver ramoops_driver = {
 489         .probe          = ramoops_probe,
 490         .remove         = __exit_p(ramoops_remove),
 491         .driver         = {
 492                 .name   = "ramoops",
 493                 .owner  = THIS_MODULE,
 494         },
 495 };
 496
 497 static void ramoops_register_dummy(void)
 498 {
 499         if (!mem_size)
 500                 return;
 501
 502         pr_info("using module parameters\n");
 503
 504         dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 505         if (!dummy_data) {
 506                 pr_info("could not allocate pdata\n");
 507                 return;
 508         }
 509
 510         dummy_data->mem_size = mem_size;
 511         dummy_data->mem_address = mem_address;
 512         dummy_data->record_size = record_size;
 513         dummy_data->console_size = ramoops_console_size;
 514         dummy_data->ftrace_size = ramoops_ftrace_size;
 515         dummy_data->dump_oops = dump_oops;
 516         /*
 517          * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 518          * (using 1 byte for ECC isn't much of use anyway).
 519          */
 520         dummy_data->ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 521
 522         dummy = platform_device_register_data(NULL, "ramoops", -1,
 523                         dummy_data, sizeof(struct ramoops_platform_data));
 524         if (IS_ERR(dummy)) {
 525                 pr_info("could not create platform device: %ld\n",
 526                         PTR_ERR(dummy));
 527         }
 528 }
 529
 530 static int __init ramoops_init(void)
 531 {
 532         ramoops_register_dummy();
 533         return platform_driver_register(&ramoops_driver);
 534 }
 535 postcore_initcall(ramoops_init);
 536
 537 static void __exit ramoops_exit(void)
 538 {
 539         platform_driver_unregister(&ramoops_driver);
 540         kfree(dummy_data);
 541 }
 542 module_exit(ramoops_exit);
 543
 544 MODULE_LICENSE("GPL");
 545 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 546 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");