fs/pstore/ram.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * RAM Oops/Panic logger
   4  *
   5  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
   6  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/kernel.h>
  12 #include <linux/err.h>
  13 #include <linux/module.h>
  14 #include <linux/version.h>
  15 #include <linux/pstore.h>
  16 #include <linux/io.h>
  17 #include <linux/ioport.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20 #include <linux/compiler.h>
  21 #include <linux/of.h>
  22 #include <linux/of_address.h>
  23
  24 #include "internal.h"
  25 #include "ram_internal.h"
  26
  27 #define RAMOOPS_KERNMSG_HDR "===="
  28 #define MIN_MEM_SIZE 4096UL
  29
  30 static ulong record_size = MIN_MEM_SIZE;
  31 module_param(record_size, ulong, 0400);
  32 MODULE_PARM_DESC(record_size,
  33                 "size of each dump done on oops/panic");
  34
  35 static ulong ramoops_console_size = MIN_MEM_SIZE;
  36 module_param_named(console_size, ramoops_console_size, ulong, 0400);
  37 MODULE_PARM_DESC(console_size, "size of kernel console log");
  38
  39 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  40 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  41 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  42
  43 static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
  44 module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
  45 MODULE_PARM_DESC(pmsg_size, "size of user space message log");
  46
  47 static unsigned long long mem_address;
  48 module_param_hw(mem_address, ullong, other, 0400);
  49 MODULE_PARM_DESC(mem_address,
  50                 "start of reserved RAM used to store oops/panic logs");
  51
  52 static ulong mem_size;
  53 module_param(mem_size, ulong, 0400);
  54 MODULE_PARM_DESC(mem_size,
  55                 "size of reserved RAM used to store oops/panic logs");
  56
  57 static unsigned int mem_type;
  58 module_param(mem_type, uint, 0400);
  59 MODULE_PARM_DESC(mem_type,
  60                 "memory type: 0=write-combined (default), 1=unbuffered, 2=cached");
  61
  62 static int ramoops_max_reason = -1;
  63 module_param_named(max_reason, ramoops_max_reason, int, 0400);
  64 MODULE_PARM_DESC(max_reason,
  65                  "maximum reason for kmsg dump (default 2: Oops and Panic) ");
  66
  67 static int ramoops_ecc;
  68 module_param_named(ecc, ramoops_ecc, int, 0400);
  69 MODULE_PARM_DESC(ramoops_ecc,
  70                 "if non-zero, the option enables ECC support and specifies "
  71                 "ECC buffer size in bytes (1 is a special value, means 16 "
  72                 "bytes ECC)");
  73
  74 static int ramoops_dump_oops = -1;
  75 module_param_named(dump_oops, ramoops_dump_oops, int, 0400);
  76 MODULE_PARM_DESC(dump_oops,
  77                  "(deprecated: use max_reason instead) set to 1 to dump oopses & panics, 0 to only dump panics");
  78
  79 struct ramoops_context {
  80         struct persistent_ram_zone **dprzs;     /* Oops dump zones */
  81         struct persistent_ram_zone *cprz;       /* Console zone */
  82         struct persistent_ram_zone **fprzs;     /* Ftrace zones */
  83         struct persistent_ram_zone *mprz;       /* PMSG zone */
  84         phys_addr_t phys_addr;
  85         unsigned long size;
  86         unsigned int memtype;
  87         size_t record_size;
  88         size_t console_size;
  89         size_t ftrace_size;
  90         size_t pmsg_size;
  91         u32 flags;
  92         struct persistent_ram_ecc_info ecc_info;
  93         unsigned int max_dump_cnt;
  94         unsigned int dump_write_cnt;
  95         /* _read_cnt need clear on ramoops_pstore_open */
  96         unsigned int dump_read_cnt;
  97         unsigned int console_read_cnt;
  98         unsigned int max_ftrace_cnt;
  99         unsigned int ftrace_read_cnt;
 100         unsigned int pmsg_read_cnt;
 101         struct pstore_info pstore;
 102 };
 103
 104 static struct platform_device *dummy;
 105
 106 static int ramoops_pstore_open(struct pstore_info *psi)
 107 {
 108         struct ramoops_context *cxt = psi->data;
 109
 110         cxt->dump_read_cnt = 0;
 111         cxt->console_read_cnt = 0;
 112         cxt->ftrace_read_cnt = 0;
 113         cxt->pmsg_read_cnt = 0;
 114         return 0;
 115 }
 116
 117 static struct persistent_ram_zone *
 118 ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
 119                      struct pstore_record *record)
 120 {
 121         struct persistent_ram_zone *prz;
 122
 123         /* Give up if we never existed or have hit the end. */
 124         if (!przs)
 125                 return NULL;
 126
 127         prz = przs[id];
 128         if (!prz)
 129                 return NULL;
 130
 131         /* Update old/shadowed buffer. */
 132         if (prz->type == PSTORE_TYPE_DMESG)
 133                 persistent_ram_save_old(prz);
 134
 135         if (!persistent_ram_old_size(prz))
 136                 return NULL;
 137
 138         record->type = prz->type;
 139         record->id = id;
 140
 141         return prz;
 142 }
 143
 144 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
 145                                   bool *compressed)
 146 {
 147         char data_type;
 148         int header_length = 0;
 149
 150         if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
 151                    (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
 152                    &header_length) == 3) {
 153                 time->tv_nsec *= 1000;
 154                 if (data_type == 'C')
 155                         *compressed = true;
 156                 else
 157                         *compressed = false;
 158         } else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
 159                           (time64_t *)&time->tv_sec, &time->tv_nsec,
 160                           &header_length) == 2) {
 161                 time->tv_nsec *= 1000;
 162                 *compressed = false;
 163         } else {
 164                 time->tv_sec = 0;
 165                 time->tv_nsec = 0;
 166                 *compressed = false;
 167         }
 168         return header_length;
 169 }
 170
 171 static bool prz_ok(struct persistent_ram_zone *prz)
 172 {
 173         return !!prz && !!(persistent_ram_old_size(prz) +
 174                            persistent_ram_ecc_string(prz, NULL, 0));
 175 }
 176
 177 static ssize_t ramoops_pstore_read(struct pstore_record *record)
 178 {
 179         ssize_t size = 0;
 180         struct ramoops_context *cxt = record->psi->data;
 181         struct persistent_ram_zone *prz = NULL;
 182         int header_length = 0;
 183         bool free_prz = false;
 184
 185         /*
 186          * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
 187          * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
 188          * valid time stamps, so it is initialized to zero.
 189          */
 190         record->time.tv_sec = 0;
 191         record->time.tv_nsec = 0;
 192         record->compressed = false;
 193
 194         /* Find the next valid persistent_ram_zone for DMESG */
 195         while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
 196                 prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
 197                                            record);
 198                 if (!prz_ok(prz))
 199                         continue;
 200                 header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
 201                                                       &record->time,
 202                                                       &record->compressed);
 203                 /* Clear and skip this DMESG record if it has no valid header */
 204                 if (!header_length) {
 205                         persistent_ram_free_old(prz);
 206                         persistent_ram_zap(prz);
 207                         prz = NULL;
 208                 }
 209         }
 210
 211         if (!prz_ok(prz) && !cxt->console_read_cnt++)
 212                 prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
 213
 214         if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
 215                 prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
 216
 217         /* ftrace is last since it may want to dynamically allocate memory. */
 218         if (!prz_ok(prz)) {
 219                 if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
 220                     !cxt->ftrace_read_cnt++) {
 221                         prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
 222                                                    record);
 223                 } else {
 224                         /*
 225                          * Build a new dummy record which combines all the
 226                          * per-cpu records including metadata and ecc info.
 227                          */
 228                         struct persistent_ram_zone *tmp_prz, *prz_next;
 229
 230                         tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
 231                                           GFP_KERNEL);
 232                         if (!tmp_prz)
 233                                 return -ENOMEM;
 234                         prz = tmp_prz;
 235                         free_prz = true;
 236
 237                         while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
 238                                 prz_next = ramoops_get_next_prz(cxt->fprzs,
 239                                                 cxt->ftrace_read_cnt++, record);
 240
 241                                 if (!prz_ok(prz_next))
 242                                         continue;
 243
 244                                 tmp_prz->ecc_info = prz_next->ecc_info;
 245                                 tmp_prz->corrected_bytes +=
 246                                                 prz_next->corrected_bytes;
 247                                 tmp_prz->bad_blocks += prz_next->bad_blocks;
 248
 249                                 size = pstore_ftrace_combine_log(
 250                                                 &tmp_prz->old_log,
 251                                                 &tmp_prz->old_log_size,
 252                                                 prz_next->old_log,
 253                                                 prz_next->old_log_size);
 254                                 if (size)
 255                                         goto out;
 256                         }
 257                         record->id = 0;
 258                 }
 259         }
 260
 261         if (!prz_ok(prz)) {
 262                 size = 0;
 263                 goto out;
 264         }
 265
 266         size = persistent_ram_old_size(prz) - header_length;
 267
 268         /* ECC correction notice */
 269         record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 270
 271         record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
 272         if (record->buf == NULL) {
 273                 size = -ENOMEM;
 274                 goto out;
 275         }
 276
 277         memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
 278                size);
 279
 280         persistent_ram_ecc_string(prz, record->buf + size,
 281                                   record->ecc_notice_size + 1);
 282
 283 out:
 284         if (free_prz) {
 285                 kfree(prz->old_log);
 286                 kfree(prz);
 287         }
 288
 289         return size;
 290 }
 291
 292 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 293                                      struct pstore_record *record)
 294 {
 295         char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
 296         size_t len;
 297
 298         len = scnprintf(hdr, sizeof(hdr),
 299                 RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
 300                 (time64_t)record->time.tv_sec,
 301                 record->time.tv_nsec / 1000,
 302                 record->compressed ? 'C' : 'D');
 303         persistent_ram_write(prz, hdr, len);
 304
 305         return len;
 306 }
 307
 308 static int notrace ramoops_pstore_write(struct pstore_record *record)
 309 {
 310         struct ramoops_context *cxt = record->psi->data;
 311         struct persistent_ram_zone *prz;
 312         size_t size, hlen;
 313
 314         if (record->type == PSTORE_TYPE_CONSOLE) {
 315                 if (!cxt->cprz)
 316                         return -ENOMEM;
 317                 persistent_ram_write(cxt->cprz, record->buf, record->size);
 318                 return 0;
 319         } else if (record->type == PSTORE_TYPE_FTRACE) {
 320                 int zonenum;
 321
 322                 if (!cxt->fprzs)
 323                         return -ENOMEM;
 324                 /*
 325                  * Choose zone by if we're using per-cpu buffers.
 326                  */
 327                 if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 328                         zonenum = smp_processor_id();
 329                 else
 330                         zonenum = 0;
 331
 332                 persistent_ram_write(cxt->fprzs[zonenum], record->buf,
 333                                      record->size);
 334                 return 0;
 335         } else if (record->type == PSTORE_TYPE_PMSG) {
 336                 pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
 337                 return -EINVAL;
 338         }
 339
 340         if (record->type != PSTORE_TYPE_DMESG)
 341                 return -EINVAL;
 342
 343         /*
 344          * We could filter on record->reason here if we wanted to (which
 345          * would duplicate what happened before the "max_reason" setting
 346          * was added), but that would defeat the purpose of a system
 347          * changing printk.always_kmsg_dump, so instead log everything that
 348          * the kmsg dumper sends us, since it should be doing the filtering
 349          * based on the combination of printk.always_kmsg_dump and our
 350          * requested "max_reason".
 351          */
 352
 353         /*
 354          * Explicitly only take the first part of any new crash.
 355          * If our buffer is larger than kmsg_bytes, this can never happen,
 356          * and if our buffer is smaller than kmsg_bytes, we don't want the
 357          * report split across multiple records.
 358          */
 359         if (record->part != 1)
 360                 return -ENOSPC;
 361
 362         if (!cxt->dprzs)
 363                 return -ENOSPC;
 364
 365         prz = cxt->dprzs[cxt->dump_write_cnt];
 366
 367         /*
 368          * Since this is a new crash dump, we need to reset the buffer in
 369          * case it still has an old dump present. Without this, the new dump
 370          * will get appended, which would seriously confuse anything trying
 371          * to check dump file contents. Specifically, ramoops_read_kmsg_hdr()
 372          * expects to find a dump header in the beginning of buffer data, so
 373          * we must to reset the buffer values, in order to ensure that the
 374          * header will be written to the beginning of the buffer.
 375          */
 376         persistent_ram_zap(prz);
 377
 378         /* Build header and append record contents. */
 379         hlen = ramoops_write_kmsg_hdr(prz, record);
 380         if (!hlen)
 381                 return -ENOMEM;
 382
 383         size = record->size;
 384         if (size + hlen > prz->buffer_size)
 385                 size = prz->buffer_size - hlen;
 386         persistent_ram_write(prz, record->buf, size);
 387
 388         cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 389
 390         return 0;
 391 }
 392
 393 static int notrace ramoops_pstore_write_user(struct pstore_record *record,
 394                                              const char __user *buf)
 395 {
 396         if (record->type == PSTORE_TYPE_PMSG) {
 397                 struct ramoops_context *cxt = record->psi->data;
 398
 399                 if (!cxt->mprz)
 400                         return -ENOMEM;
 401                 return persistent_ram_write_user(cxt->mprz, buf, record->size);
 402         }
 403
 404         return -EINVAL;
 405 }
 406
 407 static int ramoops_pstore_erase(struct pstore_record *record)
 408 {
 409         struct ramoops_context *cxt = record->psi->data;
 410         struct persistent_ram_zone *prz;
 411
 412         switch (record->type) {
 413         case PSTORE_TYPE_DMESG:
 414                 if (record->id >= cxt->max_dump_cnt)
 415                         return -EINVAL;
 416                 prz = cxt->dprzs[record->id];
 417                 break;
 418         case PSTORE_TYPE_CONSOLE:
 419                 prz = cxt->cprz;
 420                 break;
 421         case PSTORE_TYPE_FTRACE:
 422                 if (record->id >= cxt->max_ftrace_cnt)
 423                         return -EINVAL;
 424                 prz = cxt->fprzs[record->id];
 425                 break;
 426         case PSTORE_TYPE_PMSG:
 427                 prz = cxt->mprz;
 428                 break;
 429         default:
 430                 return -EINVAL;
 431         }
 432
 433         persistent_ram_free_old(prz);
 434         persistent_ram_zap(prz);
 435
 436         return 0;
 437 }
 438
 439 static struct ramoops_context oops_cxt = {
 440         .pstore = {
 441                 .owner  = THIS_MODULE,
 442                 .name   = "ramoops",
 443                 .open   = ramoops_pstore_open,
 444                 .read   = ramoops_pstore_read,
 445                 .write  = ramoops_pstore_write,
 446                 .write_user     = ramoops_pstore_write_user,
 447                 .erase  = ramoops_pstore_erase,
 448         },
 449 };
 450
 451 static void ramoops_free_przs(struct ramoops_context *cxt)
 452 {
 453         int i;
 454
 455         /* Free pmsg PRZ */
 456         persistent_ram_free(cxt->mprz);
 457
 458         /* Free console PRZ */
 459         persistent_ram_free(cxt->cprz);
 460
 461         /* Free dump PRZs */
 462         if (cxt->dprzs) {
 463                 for (i = 0; i < cxt->max_dump_cnt; i++)
 464                         persistent_ram_free(cxt->dprzs[i]);
 465
 466                 kfree(cxt->dprzs);
 467                 cxt->max_dump_cnt = 0;
 468         }
 469
 470         /* Free ftrace PRZs */
 471         if (cxt->fprzs) {
 472                 for (i = 0; i < cxt->max_ftrace_cnt; i++)
 473                         persistent_ram_free(cxt->fprzs[i]);
 474                 kfree(cxt->fprzs);
 475                 cxt->max_ftrace_cnt = 0;
 476         }
 477 }
 478
 479 static int ramoops_init_przs(const char *name,
 480                              struct device *dev, struct ramoops_context *cxt,
 481                              struct persistent_ram_zone ***przs,
 482                              phys_addr_t *paddr, size_t mem_sz,
 483                              ssize_t record_size,
 484                              unsigned int *cnt, u32 sig, u32 flags)
 485 {
 486         int err = -ENOMEM;
 487         int i;
 488         size_t zone_sz;
 489         struct persistent_ram_zone **prz_ar;
 490
 491         /* Allocate nothing for 0 mem_sz or 0 record_size. */
 492         if (mem_sz == 0 || record_size == 0) {
 493                 *cnt = 0;
 494                 return 0;
 495         }
 496
 497         /*
 498          * If we have a negative record size, calculate it based on
 499          * mem_sz / *cnt. If we have a positive record size, calculate
 500          * cnt from mem_sz / record_size.
 501          */
 502         if (record_size < 0) {
 503                 if (*cnt == 0)
 504                         return 0;
 505                 record_size = mem_sz / *cnt;
 506                 if (record_size == 0) {
 507                         dev_err(dev, "%s record size == 0 (%zu / %u)\n",
 508                                 name, mem_sz, *cnt);
 509                         goto fail;
 510                 }
 511         } else {
 512                 *cnt = mem_sz / record_size;
 513                 if (*cnt == 0) {
 514                         dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
 515                                 name, mem_sz, record_size);
 516                         goto fail;
 517                 }
 518         }
 519
 520         if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
 521                 dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 522                         name,
 523                         mem_sz, (unsigned long long)*paddr,
 524                         cxt->size, (unsigned long long)cxt->phys_addr);
 525                 goto fail;
 526         }
 527
 528         zone_sz = mem_sz / *cnt;
 529         if (!zone_sz) {
 530                 dev_err(dev, "%s zone size == 0\n", name);
 531                 goto fail;
 532         }
 533
 534         prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
 535         if (!prz_ar)
 536                 goto fail;
 537
 538         for (i = 0; i < *cnt; i++) {
 539                 char *label;
 540
 541                 if (*cnt == 1)
 542                         label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 543                 else
 544                         label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
 545                                           name, i, *cnt - 1);
 546                 prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
 547                                                &cxt->ecc_info,
 548                                                cxt->memtype, flags, label);
 549                 kfree(label);
 550                 if (IS_ERR(prz_ar[i])) {
 551                         err = PTR_ERR(prz_ar[i]);
 552                         dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
 553                                 name, record_size,
 554                                 (unsigned long long)*paddr, err);
 555
 556                         while (i > 0) {
 557                                 i--;
 558                                 persistent_ram_free(prz_ar[i]);
 559                         }
 560                         kfree(prz_ar);
 561                         goto fail;
 562                 }
 563                 *paddr += zone_sz;
 564                 prz_ar[i]->type = pstore_name_to_type(name);
 565         }
 566
 567         *przs = prz_ar;
 568         return 0;
 569
 570 fail:
 571         *cnt = 0;
 572         return err;
 573 }
 574
 575 static int ramoops_init_prz(const char *name,
 576                             struct device *dev, struct ramoops_context *cxt,
 577                             struct persistent_ram_zone **prz,
 578                             phys_addr_t *paddr, size_t sz, u32 sig)
 579 {
 580         char *label;
 581
 582         if (!sz)
 583                 return 0;
 584
 585         if (*paddr + sz - cxt->phys_addr > cxt->size) {
 586                 dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 587                         name, sz, (unsigned long long)*paddr,
 588                         cxt->size, (unsigned long long)cxt->phys_addr);
 589                 return -ENOMEM;
 590         }
 591
 592         label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 593         *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
 594                                   cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
 595         kfree(label);
 596         if (IS_ERR(*prz)) {
 597                 int err = PTR_ERR(*prz);
 598
 599                 dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
 600                         name, sz, (unsigned long long)*paddr, err);
 601                 return err;
 602         }
 603
 604         *paddr += sz;
 605         (*prz)->type = pstore_name_to_type(name);
 606
 607         return 0;
 608 }
 609
 610 /* Read a u32 from a dt property and make sure it's safe for an int. */
 611 static int ramoops_parse_dt_u32(struct platform_device *pdev,
 612                                 const char *propname,
 613                                 u32 default_value, u32 *value)
 614 {
 615         u32 val32 = 0;
 616         int ret;
 617
 618         ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
 619         if (ret == -EINVAL) {
 620                 /* field is missing, use default value. */
 621                 val32 = default_value;
 622         } else if (ret < 0) {
 623                 dev_err(&pdev->dev, "failed to parse property %s: %d\n",
 624                         propname, ret);
 625                 return ret;
 626         }
 627
 628         /* Sanity check our results. */
 629         if (val32 > INT_MAX) {
 630                 dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
 631                 return -EOVERFLOW;
 632         }
 633
 634         *value = val32;
 635         return 0;
 636 }
 637
 638 static int ramoops_parse_dt(struct platform_device *pdev,
 639                             struct ramoops_platform_data *pdata)
 640 {
 641         struct device_node *of_node = pdev->dev.of_node;
 642         struct device_node *parent_node;
 643         struct resource *res;
 644         u32 value;
 645         int ret;
 646
 647         dev_dbg(&pdev->dev, "using Device Tree\n");
 648
 649         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 650         if (!res) {
 651                 dev_err(&pdev->dev,
 652                         "failed to locate DT /reserved-memory resource\n");
 653                 return -EINVAL;
 654         }
 655
 656         pdata->mem_size = resource_size(res);
 657         pdata->mem_address = res->start;
 658         /*
 659          * Setting "unbuffered" is deprecated and will be ignored if
 660          * "mem_type" is also specified.
 661          */
 662         pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
 663         /*
 664          * Setting "no-dump-oops" is deprecated and will be ignored if
 665          * "max_reason" is also specified.
 666          */
 667         if (of_property_read_bool(of_node, "no-dump-oops"))
 668                 pdata->max_reason = KMSG_DUMP_PANIC;
 669         else
 670                 pdata->max_reason = KMSG_DUMP_OOPS;
 671
 672 #define parse_u32(name, field, default_value) {                         \
 673                 ret = ramoops_parse_dt_u32(pdev, name, default_value,   \
 674                                             &value);                    \
 675                 if (ret < 0)                                            \
 676                         return ret;                                     \
 677                 field = value;                                          \
 678         }
 679
 680         parse_u32("mem-type", pdata->record_size, pdata->mem_type);
 681         parse_u32("record-size", pdata->record_size, 0);
 682         parse_u32("console-size", pdata->console_size, 0);
 683         parse_u32("ftrace-size", pdata->ftrace_size, 0);
 684         parse_u32("pmsg-size", pdata->pmsg_size, 0);
 685         parse_u32("ecc-size", pdata->ecc_info.ecc_size, 0);
 686         parse_u32("flags", pdata->flags, 0);
 687         parse_u32("max-reason", pdata->max_reason, pdata->max_reason);
 688
 689 #undef parse_u32
 690
 691         /*
 692          * Some old Chromebooks relied on the kernel setting the
 693          * console_size and pmsg_size to the record size since that's
 694          * what the downstream kernel did.  These same Chromebooks had
 695          * "ramoops" straight under the root node which isn't
 696          * according to the current upstream bindings (though it was
 697          * arguably acceptable under a prior version of the bindings).
 698          * Let's make those old Chromebooks work by detecting that
 699          * we're not a child of "reserved-memory" and mimicking the
 700          * expected behavior.
 701          */
 702         parent_node = of_get_parent(of_node);
 703         if (!of_node_name_eq(parent_node, "reserved-memory") &&
 704             !pdata->console_size && !pdata->ftrace_size &&
 705             !pdata->pmsg_size && !pdata->ecc_info.ecc_size) {
 706                 pdata->console_size = pdata->record_size;
 707                 pdata->pmsg_size = pdata->record_size;
 708         }
 709         of_node_put(parent_node);
 710
 711         return 0;
 712 }
 713
 714 static int ramoops_probe(struct platform_device *pdev)
 715 {
 716         struct device *dev = &pdev->dev;
 717         struct ramoops_platform_data *pdata = dev->platform_data;
 718         struct ramoops_platform_data pdata_local;
 719         struct ramoops_context *cxt = &oops_cxt;
 720         size_t dump_mem_sz;
 721         phys_addr_t paddr;
 722         int err = -EINVAL;
 723
 724         /*
 725          * Only a single ramoops area allowed at a time, so fail extra
 726          * probes.
 727          */
 728         if (cxt->max_dump_cnt) {
 729                 pr_err("already initialized\n");
 730                 goto fail_out;
 731         }
 732
 733         if (dev_of_node(dev) && !pdata) {
 734                 pdata = &pdata_local;
 735                 memset(pdata, 0, sizeof(*pdata));
 736
 737                 err = ramoops_parse_dt(pdev, pdata);
 738                 if (err < 0)
 739                         goto fail_out;
 740         }
 741
 742         /* Make sure we didn't get bogus platform data pointer. */
 743         if (!pdata) {
 744                 pr_err("NULL platform data\n");
 745                 goto fail_out;
 746         }
 747
 748         if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 749                         !pdata->ftrace_size && !pdata->pmsg_size)) {
 750                 pr_err("The memory size and the record/console size must be "
 751                         "non-zero\n");
 752                 goto fail_out;
 753         }
 754
 755         if (pdata->record_size && !is_power_of_2(pdata->record_size))
 756                 pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 757         if (pdata->console_size && !is_power_of_2(pdata->console_size))
 758                 pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 759         if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
 760                 pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 761         if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
 762                 pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
 763
 764         cxt->size = pdata->mem_size;
 765         cxt->phys_addr = pdata->mem_address;
 766         cxt->memtype = pdata->mem_type;
 767         cxt->record_size = pdata->record_size;
 768         cxt->console_size = pdata->console_size;
 769         cxt->ftrace_size = pdata->ftrace_size;
 770         cxt->pmsg_size = pdata->pmsg_size;
 771         cxt->flags = pdata->flags;
 772         cxt->ecc_info = pdata->ecc_info;
 773
 774         paddr = cxt->phys_addr;
 775
 776         dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
 777                         - cxt->pmsg_size;
 778         err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
 779                                 dump_mem_sz, cxt->record_size,
 780                                 &cxt->max_dump_cnt, 0, 0);
 781         if (err)
 782                 goto fail_init;
 783
 784         err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
 785                                cxt->console_size, 0);
 786         if (err)
 787                 goto fail_init;
 788
 789         err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
 790                                 cxt->pmsg_size, 0);
 791         if (err)
 792                 goto fail_init;
 793
 794         cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 795                                 ? nr_cpu_ids
 796                                 : 1;
 797         err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
 798                                 cxt->ftrace_size, -1,
 799                                 &cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
 800                                 (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 801                                         ? PRZ_FLAG_NO_LOCK : 0);
 802         if (err)
 803                 goto fail_init;
 804
 805         cxt->pstore.data = cxt;
 806         /*
 807          * Prepare frontend flags based on which areas are initialized.
 808          * For ramoops_init_przs() cases, the "max count" variable tells
 809          * if there are regions present. For ramoops_init_prz() cases,
 810          * the single region size is how to check.
 811          */
 812         cxt->pstore.flags = 0;
 813         if (cxt->max_dump_cnt) {
 814                 cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
 815                 cxt->pstore.max_reason = pdata->max_reason;
 816         }
 817         if (cxt->console_size)
 818                 cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
 819         if (cxt->max_ftrace_cnt)
 820                 cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
 821         if (cxt->pmsg_size)
 822                 cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
 823
 824         /*
 825          * Since bufsize is only used for dmesg crash dumps, it
 826          * must match the size of the dprz record (after PRZ header
 827          * and ECC bytes have been accounted for).
 828          */
 829         if (cxt->pstore.flags & PSTORE_FLAGS_DMESG) {
 830                 cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
 831                 cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
 832                 if (!cxt->pstore.buf) {
 833                         pr_err("cannot allocate pstore crash dump buffer\n");
 834                         err = -ENOMEM;
 835                         goto fail_clear;
 836                 }
 837         }
 838
 839         err = pstore_register(&cxt->pstore);
 840         if (err) {
 841                 pr_err("registering with pstore failed\n");
 842                 goto fail_buf;
 843         }
 844
 845         /*
 846          * Update the module parameter variables as well so they are visible
 847          * through /sys/module/ramoops/parameters/
 848          */
 849         mem_size = pdata->mem_size;
 850         mem_address = pdata->mem_address;
 851         record_size = pdata->record_size;
 852         ramoops_max_reason = pdata->max_reason;
 853         ramoops_console_size = pdata->console_size;
 854         ramoops_pmsg_size = pdata->pmsg_size;
 855         ramoops_ftrace_size = pdata->ftrace_size;
 856
 857         pr_info("using 0x%lx@0x%llx, ecc: %d\n",
 858                 cxt->size, (unsigned long long)cxt->phys_addr,
 859                 cxt->ecc_info.ecc_size);
 860
 861         return 0;
 862
 863 fail_buf:
 864         kfree(cxt->pstore.buf);
 865 fail_clear:
 866         cxt->pstore.bufsize = 0;
 867 fail_init:
 868         ramoops_free_przs(cxt);
 869 fail_out:
 870         return err;
 871 }
 872
 873 static int ramoops_remove(struct platform_device *pdev)
 874 {
 875         struct ramoops_context *cxt = &oops_cxt;
 876
 877         pstore_unregister(&cxt->pstore);
 878
 879         kfree(cxt->pstore.buf);
 880         cxt->pstore.bufsize = 0;
 881
 882         ramoops_free_przs(cxt);
 883
 884         return 0;
 885 }
 886
 887 static const struct of_device_id dt_match[] = {
 888         { .compatible = "ramoops" },
 889         {}
 890 };
 891
 892 static struct platform_driver ramoops_driver = {
 893         .probe          = ramoops_probe,
 894         .remove         = ramoops_remove,
 895         .driver         = {
 896                 .name           = "ramoops",
 897                 .of_match_table = dt_match,
 898         },
 899 };
 900
 901 static inline void ramoops_unregister_dummy(void)
 902 {
 903         platform_device_unregister(dummy);
 904         dummy = NULL;
 905 }
 906
 907 static void __init ramoops_register_dummy(void)
 908 {
 909         struct ramoops_platform_data pdata;
 910
 911         /*
 912          * Prepare a dummy platform data structure to carry the module
 913          * parameters. If mem_size isn't set, then there are no module
 914          * parameters, and we can skip this.
 915          */
 916         if (!mem_size)
 917                 return;
 918
 919         pr_info("using module parameters\n");
 920
 921         memset(&pdata, 0, sizeof(pdata));
 922         pdata.mem_size = mem_size;
 923         pdata.mem_address = mem_address;
 924         pdata.mem_type = mem_type;
 925         pdata.record_size = record_size;
 926         pdata.console_size = ramoops_console_size;
 927         pdata.ftrace_size = ramoops_ftrace_size;
 928         pdata.pmsg_size = ramoops_pmsg_size;
 929         /* If "max_reason" is set, its value has priority over "dump_oops". */
 930         if (ramoops_max_reason >= 0)
 931                 pdata.max_reason = ramoops_max_reason;
 932         /* Otherwise, if "dump_oops" is set, parse it into "max_reason". */
 933         else if (ramoops_dump_oops != -1)
 934                 pdata.max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS
 935                                                      : KMSG_DUMP_PANIC;
 936         /* And if neither are explicitly set, use the default. */
 937         else
 938                 pdata.max_reason = KMSG_DUMP_OOPS;
 939         pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
 940
 941         /*
 942          * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 943          * (using 1 byte for ECC isn't much of use anyway).
 944          */
 945         pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 946
 947         dummy = platform_device_register_data(NULL, "ramoops", -1,
 948                         &pdata, sizeof(pdata));
 949         if (IS_ERR(dummy)) {
 950                 pr_info("could not create platform device: %ld\n",
 951                         PTR_ERR(dummy));
 952                 dummy = NULL;
 953         }
 954 }
 955
 956 static int __init ramoops_init(void)
 957 {
 958         int ret;
 959
 960         ramoops_register_dummy();
 961         ret = platform_driver_register(&ramoops_driver);
 962         if (ret != 0)
 963                 ramoops_unregister_dummy();
 964
 965         return ret;
 966 }
 967 postcore_initcall(ramoops_init);
 968
 969 static void __exit ramoops_exit(void)
 970 {
 971         platform_driver_unregister(&ramoops_driver);
 972         ramoops_unregister_dummy();
 973 }
 974 module_exit(ramoops_exit);
 975
 976 MODULE_LICENSE("GPL");
 977 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 978 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");