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