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/pstore.h>
  29 #include <linux/time.h>
  30 #include <linux/io.h>
  31 #include <linux/ioport.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/slab.h>
  34 #include <linux/pstore_ram.h>
  35
  36 #define RAMOOPS_KERNMSG_HDR "===="
  37 #define MIN_MEM_SIZE 4096UL
  38
  39 static ulong record_size = MIN_MEM_SIZE;
  40 module_param(record_size, ulong, 0400);
  41 MODULE_PARM_DESC(record_size,
  42                 "size of each dump done on oops/panic");
  43
  44 static ulong ramoops_console_size = MIN_MEM_SIZE;
  45 module_param_named(console_size, ramoops_console_size, ulong, 0400);
  46 MODULE_PARM_DESC(console_size, "size of kernel console log");
  47
  48 static ulong mem_address;
  49 module_param(mem_address, ulong, 0400);
  50 MODULE_PARM_DESC(mem_address,
  51                 "start of reserved RAM used to store oops/panic logs");
  52
  53 static ulong mem_size;
  54 module_param(mem_size, ulong, 0400);
  55 MODULE_PARM_DESC(mem_size,
  56                 "size of reserved RAM used to store oops/panic logs");
  57
  58 static int dump_oops = 1;
  59 module_param(dump_oops, int, 0600);
  60 MODULE_PARM_DESC(dump_oops,
  61                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  62
  63 static int ramoops_ecc;
  64 module_param_named(ecc, ramoops_ecc, int, 0600);
  65 MODULE_PARM_DESC(ramoops_ecc,
  66                 "if non-zero, the option enables ECC support and specifies "
  67                 "ECC buffer size in bytes (1 is a special value, means 16 "
  68                 "bytes ECC)");
  69
  70 struct ramoops_context {
  71         struct persistent_ram_zone **przs;
  72         struct persistent_ram_zone *cprz;
  73         phys_addr_t phys_addr;
  74         unsigned long size;
  75         size_t record_size;
  76         size_t console_size;
  77         int dump_oops;
  78         int ecc_size;
  79         unsigned int max_dump_cnt;
  80         unsigned int dump_write_cnt;
  81         unsigned int dump_read_cnt;
  82         unsigned int console_read_cnt;
  83         struct pstore_info pstore;
  84 };
  85
  86 static struct platform_device *dummy;
  87 static struct ramoops_platform_data *dummy_data;
  88
  89 static int ramoops_pstore_open(struct pstore_info *psi)
  90 {
  91         struct ramoops_context *cxt = psi->data;
  92
  93         cxt->dump_read_cnt = 0;
  94         cxt->console_read_cnt = 0;
  95         return 0;
  96 }
  97
  98 static struct persistent_ram_zone *
  99 ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 100                      u64 *id,
 101                      enum pstore_type_id *typep, enum pstore_type_id type,
 102                      bool update)
 103 {
 104         struct persistent_ram_zone *prz;
 105         int i = (*c)++;
 106
 107         if (i >= max)
 108                 return NULL;
 109
 110         prz = przs[i];
 111
 112         if (update) {
 113                 /* Update old/shadowed buffer. */
 114                 persistent_ram_save_old(prz);
 115                 if (!persistent_ram_old_size(prz))
 116                         return NULL;
 117         }
 118
 119         *typep = type;
 120         *id = i;
 121
 122         return prz;
 123 }
 124
 125 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 126                                    struct timespec *time,
 127                                    char **buf,
 128                                    struct pstore_info *psi)
 129 {
 130         ssize_t size;
 131         struct ramoops_context *cxt = psi->data;
 132         struct persistent_ram_zone *prz;
 133
 134         prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
 135                                    cxt->max_dump_cnt, id, type,
 136                                    PSTORE_TYPE_DMESG, 1);
 137         if (!prz)
 138                 prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
 139                                            1, id, type, PSTORE_TYPE_CONSOLE, 0);
 140         if (!prz)
 141                 return 0;
 142
 143         /* TODO(kees): Bogus time for the moment. */
 144         time->tv_sec = 0;
 145         time->tv_nsec = 0;
 146
 147         size = persistent_ram_old_size(prz);
 148         *buf = kmalloc(size, GFP_KERNEL);
 149         if (*buf == NULL)
 150                 return -ENOMEM;
 151         memcpy(*buf, persistent_ram_old(prz), size);
 152
 153         return size;
 154 }
 155
 156 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 157 {
 158         char *hdr;
 159         struct timeval timestamp;
 160         size_t len;
 161
 162         do_gettimeofday(&timestamp);
 163         hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
 164                 (long)timestamp.tv_sec, (long)timestamp.tv_usec);
 165         WARN_ON_ONCE(!hdr);
 166         len = hdr ? strlen(hdr) : 0;
 167         persistent_ram_write(prz, hdr, len);
 168         kfree(hdr);
 169
 170         return len;
 171 }
 172
 173
 174 static int ramoops_pstore_write_buf(enum pstore_type_id type,
 175                                     enum kmsg_dump_reason reason,
 176                                     u64 *id, unsigned int part,
 177                                     const char *buf, size_t size,
 178                                     struct pstore_info *psi)
 179 {
 180         struct ramoops_context *cxt = psi->data;
 181         struct persistent_ram_zone *prz = cxt->przs[cxt->dump_write_cnt];
 182         size_t hlen;
 183
 184         if (type == PSTORE_TYPE_CONSOLE) {
 185                 if (!cxt->cprz)
 186                         return -ENOMEM;
 187                 persistent_ram_write(cxt->cprz, buf, size);
 188                 return 0;
 189         }
 190
 191         if (type != PSTORE_TYPE_DMESG)
 192                 return -EINVAL;
 193
 194         /* Out of the various dmesg dump types, ramoops is currently designed
 195          * to only store crash logs, rather than storing general kernel logs.
 196          */
 197         if (reason != KMSG_DUMP_OOPS &&
 198             reason != KMSG_DUMP_PANIC)
 199                 return -EINVAL;
 200
 201         /* Skip Oopes when configured to do so. */
 202         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 203                 return -EINVAL;
 204
 205         /* Explicitly only take the first part of any new crash.
 206          * If our buffer is larger than kmsg_bytes, this can never happen,
 207          * and if our buffer is smaller than kmsg_bytes, we don't want the
 208          * report split across multiple records.
 209          */
 210         if (part != 1)
 211                 return -ENOSPC;
 212
 213         hlen = ramoops_write_kmsg_hdr(prz);
 214         if (size + hlen > prz->buffer_size)
 215                 size = prz->buffer_size - hlen;
 216         persistent_ram_write(prz, buf, size);
 217
 218         cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 219
 220         return 0;
 221 }
 222
 223 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
 224                                 struct pstore_info *psi)
 225 {
 226         struct ramoops_context *cxt = psi->data;
 227         struct persistent_ram_zone *prz;
 228
 229         switch (type) {
 230         case PSTORE_TYPE_DMESG:
 231                 if (id >= cxt->max_dump_cnt)
 232                         return -EINVAL;
 233                 prz = cxt->przs[id];
 234                 break;
 235         case PSTORE_TYPE_CONSOLE:
 236                 prz = cxt->cprz;
 237                 break;
 238         default:
 239                 return -EINVAL;
 240         }
 241
 242         persistent_ram_free_old(prz);
 243         persistent_ram_zap(prz);
 244
 245         return 0;
 246 }
 247
 248 static struct ramoops_context oops_cxt = {
 249         .pstore = {
 250                 .owner  = THIS_MODULE,
 251                 .name   = "ramoops",
 252                 .open   = ramoops_pstore_open,
 253                 .read   = ramoops_pstore_read,
 254                 .write_buf      = ramoops_pstore_write_buf,
 255                 .erase  = ramoops_pstore_erase,
 256         },
 257 };
 258
 259 static void ramoops_free_przs(struct ramoops_context *cxt)
 260 {
 261         int i;
 262
 263         if (!cxt->przs)
 264                 return;
 265
 266         for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
 267                 persistent_ram_free(cxt->przs[i]);
 268         kfree(cxt->przs);
 269 }
 270
 271 static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 272                               phys_addr_t *paddr, size_t dump_mem_sz)
 273 {
 274         int err = -ENOMEM;
 275         int i;
 276
 277         if (!cxt->record_size)
 278                 return 0;
 279
 280         cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
 281         if (!cxt->max_dump_cnt)
 282                 return -ENOMEM;
 283
 284         cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
 285                              GFP_KERNEL);
 286         if (!cxt->przs) {
 287                 dev_err(dev, "failed to initialize a prz array for dumps\n");
 288                 return -ENOMEM;
 289         }
 290
 291         for (i = 0; i < cxt->max_dump_cnt; i++) {
 292                 size_t sz = cxt->record_size;
 293
 294                 cxt->przs[i] = persistent_ram_new(*paddr, sz, cxt->ecc_size);
 295                 if (IS_ERR(cxt->przs[i])) {
 296                         err = PTR_ERR(cxt->przs[i]);
 297                         dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 298                                 sz, (unsigned long long)*paddr, err);
 299                         goto fail_prz;
 300                 }
 301                 *paddr += sz;
 302         }
 303
 304         return 0;
 305 fail_prz:
 306         ramoops_free_przs(cxt);
 307         return err;
 308 }
 309
 310 static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 311                             struct persistent_ram_zone **prz,
 312                             phys_addr_t *paddr, size_t sz)
 313 {
 314         if (!sz)
 315                 return 0;
 316
 317         if (*paddr + sz > *paddr + cxt->size)
 318                 return -ENOMEM;
 319
 320         *prz = persistent_ram_new(*paddr, sz, cxt->ecc_size);
 321         if (IS_ERR(*prz)) {
 322                 int err = PTR_ERR(*prz);
 323
 324                 dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 325                         sz, (unsigned long long)*paddr, err);
 326                 return err;
 327         }
 328
 329         persistent_ram_zap(*prz);
 330
 331         *paddr += sz;
 332
 333         return 0;
 334 }
 335
 336 static int __devinit ramoops_probe(struct platform_device *pdev)
 337 {
 338         struct device *dev = &pdev->dev;
 339         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 340         struct ramoops_context *cxt = &oops_cxt;
 341         size_t dump_mem_sz;
 342         phys_addr_t paddr;
 343         int err = -EINVAL;
 344
 345         /* Only a single ramoops area allowed at a time, so fail extra
 346          * probes.
 347          */
 348         if (cxt->max_dump_cnt)
 349                 goto fail_out;
 350
 351         if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size)) {
 352                 pr_err("The memory size and the record/console size must be "
 353                         "non-zero\n");
 354                 goto fail_out;
 355         }
 356
 357         pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 358         pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 359         pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 360
 361         cxt->dump_read_cnt = 0;
 362         cxt->size = pdata->mem_size;
 363         cxt->phys_addr = pdata->mem_address;
 364         cxt->record_size = pdata->record_size;
 365         cxt->console_size = pdata->console_size;
 366         cxt->dump_oops = pdata->dump_oops;
 367         cxt->ecc_size = pdata->ecc_size;
 368
 369         paddr = cxt->phys_addr;
 370
 371         dump_mem_sz = cxt->size - cxt->console_size;
 372         err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 373         if (err)
 374                 goto fail_out;
 375
 376         err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr, cxt->console_size);
 377         if (err)
 378                 goto fail_init_cprz;
 379
 380         if (!cxt->przs && !cxt->cprz) {
 381                 pr_err("memory size too small, minimum is %lu\n",
 382                         cxt->console_size + cxt->record_size);
 383                 goto fail_cnt;
 384         }
 385
 386         cxt->pstore.data = cxt;
 387         /*
 388          * Console can handle any buffer size, so prefer dumps buffer
 389          * size since usually it is smaller.
 390          */
 391         if (cxt->przs)
 392                 cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
 393         else
 394                 cxt->pstore.bufsize = cxt->cprz->buffer_size;
 395         cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 396         spin_lock_init(&cxt->pstore.buf_lock);
 397         if (!cxt->pstore.buf) {
 398                 pr_err("cannot allocate pstore buffer\n");
 399                 goto fail_clear;
 400         }
 401
 402         err = pstore_register(&cxt->pstore);
 403         if (err) {
 404                 pr_err("registering with pstore failed\n");
 405                 goto fail_buf;
 406         }
 407
 408         /*
 409          * Update the module parameter variables as well so they are visible
 410          * through /sys/module/ramoops/parameters/
 411          */
 412         mem_size = pdata->mem_size;
 413         mem_address = pdata->mem_address;
 414         record_size = pdata->record_size;
 415         dump_oops = pdata->dump_oops;
 416
 417         pr_info("attached 0x%lx@0x%llx, ecc: %d\n",
 418                 cxt->size, (unsigned long long)cxt->phys_addr,
 419                 cxt->ecc_size);
 420
 421         return 0;
 422
 423 fail_buf:
 424         kfree(cxt->pstore.buf);
 425 fail_clear:
 426         cxt->pstore.bufsize = 0;
 427         cxt->max_dump_cnt = 0;
 428 fail_cnt:
 429         kfree(cxt->cprz);
 430 fail_init_cprz:
 431         ramoops_free_przs(cxt);
 432 fail_out:
 433         return err;
 434 }
 435
 436 static int __exit ramoops_remove(struct platform_device *pdev)
 437 {
 438 #if 0
 439         /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 440          * unregistering yet.
 441          */
 442         struct ramoops_context *cxt = &oops_cxt;
 443
 444         iounmap(cxt->virt_addr);
 445         release_mem_region(cxt->phys_addr, cxt->size);
 446         cxt->max_dump_cnt = 0;
 447
 448         /* TODO(kees): When pstore supports unregistering, call it here. */
 449         kfree(cxt->pstore.buf);
 450         cxt->pstore.bufsize = 0;
 451
 452         return 0;
 453 #endif
 454         return -EBUSY;
 455 }
 456
 457 static struct platform_driver ramoops_driver = {
 458         .probe          = ramoops_probe,
 459         .remove         = __exit_p(ramoops_remove),
 460         .driver         = {
 461                 .name   = "ramoops",
 462                 .owner  = THIS_MODULE,
 463         },
 464 };
 465
 466 static void ramoops_register_dummy(void)
 467 {
 468         if (!mem_size)
 469                 return;
 470
 471         pr_info("using module parameters\n");
 472
 473         dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 474         if (!dummy_data) {
 475                 pr_info("could not allocate pdata\n");
 476                 return;
 477         }
 478
 479         dummy_data->mem_size = mem_size;
 480         dummy_data->mem_address = mem_address;
 481         dummy_data->record_size = record_size;
 482         dummy_data->console_size = ramoops_console_size;
 483         dummy_data->dump_oops = dump_oops;
 484         /*
 485          * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 486          * (using 1 byte for ECC isn't much of use anyway).
 487          */
 488         dummy_data->ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 489
 490         dummy = platform_device_register_data(NULL, "ramoops", -1,
 491                         dummy_data, sizeof(struct ramoops_platform_data));
 492         if (IS_ERR(dummy)) {
 493                 pr_info("could not create platform device: %ld\n",
 494                         PTR_ERR(dummy));
 495         }
 496 }
 497
 498 static int __init ramoops_init(void)
 499 {
 500         ramoops_register_dummy();
 501         return platform_driver_register(&ramoops_driver);
 502 }
 503 postcore_initcall(ramoops_init);
 504
 505 static void __exit ramoops_exit(void)
 506 {
 507         platform_driver_unregister(&ramoops_driver);
 508         kfree(dummy_data);
 509 }
 510 module_exit(ramoops_exit);
 511
 512 MODULE_LICENSE("GPL");
 513 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 514 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");