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/pstore_ram.h>
  22 #include <linux/of.h>
  23 #include <linux/of_address.h>
  24
  25 #define RAMOOPS_KERNMSG_HDR "===="
  26 #define MIN_MEM_SIZE 4096UL
  27
  28 static ulong record_size = MIN_MEM_SIZE;
  29 module_param(record_size, ulong, 0400);
  30 MODULE_PARM_DESC(record_size,
  31                 "size of each dump done on oops/panic");
  32
  33 static ulong ramoops_console_size = MIN_MEM_SIZE;
  34 module_param_named(console_size, ramoops_console_size, ulong, 0400);
  35 MODULE_PARM_DESC(console_size, "size of kernel console log");
  36
  37 static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  38 module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  39 MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  40
  41 static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
  42 module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
  43 MODULE_PARM_DESC(pmsg_size, "size of user space message log");
  44
  45 static unsigned long long mem_address;
  46 module_param_hw(mem_address, ullong, other, 0400);
  47 MODULE_PARM_DESC(mem_address,
  48                 "start of reserved RAM used to store oops/panic logs");
  49
  50 static ulong mem_size;
  51 module_param(mem_size, ulong, 0400);
  52 MODULE_PARM_DESC(mem_size,
  53                 "size of reserved RAM used to store oops/panic logs");
  54
  55 static unsigned int mem_type;
  56 module_param(mem_type, uint, 0600);
  57 MODULE_PARM_DESC(mem_type,
  58                 "set to 1 to try to use unbuffered memory (default 0)");
  59
  60 static int dump_oops = 1;
  61 module_param(dump_oops, int, 0600);
  62 MODULE_PARM_DESC(dump_oops,
  63                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  64
  65 static int ramoops_ecc;
  66 module_param_named(ecc, ramoops_ecc, int, 0600);
  67 MODULE_PARM_DESC(ramoops_ecc,
  68                 "if non-zero, the option enables ECC support and specifies "
  69                 "ECC buffer size in bytes (1 is a special value, means 16 "
  70                 "bytes ECC)");
  71
  72 struct ramoops_context {
  73         struct persistent_ram_zone **dprzs;     /* Oops dump zones */
  74         struct persistent_ram_zone *cprz;       /* Console zone */
  75         struct persistent_ram_zone **fprzs;     /* Ftrace zones */
  76         struct persistent_ram_zone *mprz;       /* PMSG zone */
  77         phys_addr_t phys_addr;
  78         unsigned long size;
  79         unsigned int memtype;
  80         size_t record_size;
  81         size_t console_size;
  82         size_t ftrace_size;
  83         size_t pmsg_size;
  84         int dump_oops;
  85         u32 flags;
  86         struct persistent_ram_ecc_info ecc_info;
  87         unsigned int max_dump_cnt;
  88         unsigned int dump_write_cnt;
  89         /* _read_cnt need clear on ramoops_pstore_open */
  90         unsigned int dump_read_cnt;
  91         unsigned int console_read_cnt;
  92         unsigned int max_ftrace_cnt;
  93         unsigned int ftrace_read_cnt;
  94         unsigned int pmsg_read_cnt;
  95         struct pstore_info pstore;
  96 };
  97
  98 static struct platform_device *dummy;
  99
 100 static int ramoops_pstore_open(struct pstore_info *psi)
 101 {
 102         struct ramoops_context *cxt = psi->data;
 103
 104         cxt->dump_read_cnt = 0;
 105         cxt->console_read_cnt = 0;
 106         cxt->ftrace_read_cnt = 0;
 107         cxt->pmsg_read_cnt = 0;
 108         return 0;
 109 }
 110
 111 static struct persistent_ram_zone *
 112 ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
 113                      struct pstore_record *record)
 114 {
 115         struct persistent_ram_zone *prz;
 116
 117         /* Give up if we never existed or have hit the end. */
 118         if (!przs)
 119                 return NULL;
 120
 121         prz = przs[id];
 122         if (!prz)
 123                 return NULL;
 124
 125         /* Update old/shadowed buffer. */
 126         if (prz->type == PSTORE_TYPE_DMESG)
 127                 persistent_ram_save_old(prz);
 128
 129         if (!persistent_ram_old_size(prz))
 130                 return NULL;
 131
 132         record->type = prz->type;
 133         record->id = id;
 134
 135         return prz;
 136 }
 137
 138 static int ramoops_read_kmsg_hdr(char *buffer, struct timespec64 *time,
 139                                   bool *compressed)
 140 {
 141         char data_type;
 142         int header_length = 0;
 143
 144         if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu-%c\n%n",
 145                    (time64_t *)&time->tv_sec, &time->tv_nsec, &data_type,
 146                    &header_length) == 3) {
 147                 time->tv_nsec *= 1000;
 148                 if (data_type == 'C')
 149                         *compressed = true;
 150                 else
 151                         *compressed = false;
 152         } else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lld.%lu\n%n",
 153                           (time64_t *)&time->tv_sec, &time->tv_nsec,
 154                           &header_length) == 2) {
 155                 time->tv_nsec *= 1000;
 156                 *compressed = false;
 157         } else {
 158                 time->tv_sec = 0;
 159                 time->tv_nsec = 0;
 160                 *compressed = false;
 161         }
 162         return header_length;
 163 }
 164
 165 static bool prz_ok(struct persistent_ram_zone *prz)
 166 {
 167         return !!prz && !!(persistent_ram_old_size(prz) +
 168                            persistent_ram_ecc_string(prz, NULL, 0));
 169 }
 170
 171 static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,
 172                                   struct persistent_ram_zone *src)
 173 {
 174         size_t dest_size, src_size, total, dest_off, src_off;
 175         size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
 176         void *merged_buf;
 177         struct pstore_ftrace_record *drec, *srec, *mrec;
 178         size_t record_size = sizeof(struct pstore_ftrace_record);
 179
 180         dest_off = dest->old_log_size % record_size;
 181         dest_size = dest->old_log_size - dest_off;
 182
 183         src_off = src->old_log_size % record_size;
 184         src_size = src->old_log_size - src_off;
 185
 186         total = dest_size + src_size;
 187         merged_buf = kmalloc(total, GFP_KERNEL);
 188         if (!merged_buf)
 189                 return -ENOMEM;
 190
 191         drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off);
 192         srec = (struct pstore_ftrace_record *)(src->old_log + src_off);
 193         mrec = (struct pstore_ftrace_record *)(merged_buf);
 194
 195         while (dest_size > 0 && src_size > 0) {
 196                 if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
 197                     pstore_ftrace_read_timestamp(&srec[src_idx])) {
 198                         mrec[merged_idx++] = drec[dest_idx++];
 199                         dest_size -= record_size;
 200                 } else {
 201                         mrec[merged_idx++] = srec[src_idx++];
 202                         src_size -= record_size;
 203                 }
 204         }
 205
 206         while (dest_size > 0) {
 207                 mrec[merged_idx++] = drec[dest_idx++];
 208                 dest_size -= record_size;
 209         }
 210
 211         while (src_size > 0) {
 212                 mrec[merged_idx++] = srec[src_idx++];
 213                 src_size -= record_size;
 214         }
 215
 216         kfree(dest->old_log);
 217         dest->old_log = merged_buf;
 218         dest->old_log_size = total;
 219
 220         return 0;
 221 }
 222
 223 static ssize_t ramoops_pstore_read(struct pstore_record *record)
 224 {
 225         ssize_t size = 0;
 226         struct ramoops_context *cxt = record->psi->data;
 227         struct persistent_ram_zone *prz = NULL;
 228         int header_length = 0;
 229         bool free_prz = false;
 230
 231         /*
 232          * Ramoops headers provide time stamps for PSTORE_TYPE_DMESG, but
 233          * PSTORE_TYPE_CONSOLE and PSTORE_TYPE_FTRACE don't currently have
 234          * valid time stamps, so it is initialized to zero.
 235          */
 236         record->time.tv_sec = 0;
 237         record->time.tv_nsec = 0;
 238         record->compressed = false;
 239
 240         /* Find the next valid persistent_ram_zone for DMESG */
 241         while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
 242                 prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
 243                                            record);
 244                 if (!prz_ok(prz))
 245                         continue;
 246                 header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
 247                                                       &record->time,
 248                                                       &record->compressed);
 249                 /* Clear and skip this DMESG record if it has no valid header */
 250                 if (!header_length) {
 251                         persistent_ram_free_old(prz);
 252                         persistent_ram_zap(prz);
 253                         prz = NULL;
 254                 }
 255         }
 256
 257         if (!prz_ok(prz) && !cxt->console_read_cnt++)
 258                 prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
 259
 260         if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
 261                 prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
 262
 263         /* ftrace is last since it may want to dynamically allocate memory. */
 264         if (!prz_ok(prz)) {
 265                 if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
 266                     !cxt->ftrace_read_cnt++) {
 267                         prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
 268                                                    record);
 269                 } else {
 270                         /*
 271                          * Build a new dummy record which combines all the
 272                          * per-cpu records including metadata and ecc info.
 273                          */
 274                         struct persistent_ram_zone *tmp_prz, *prz_next;
 275
 276                         tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
 277                                           GFP_KERNEL);
 278                         if (!tmp_prz)
 279                                 return -ENOMEM;
 280                         prz = tmp_prz;
 281                         free_prz = true;
 282
 283                         while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
 284                                 prz_next = ramoops_get_next_prz(cxt->fprzs,
 285                                                 cxt->ftrace_read_cnt++, record);
 286
 287                                 if (!prz_ok(prz_next))
 288                                         continue;
 289
 290                                 tmp_prz->ecc_info = prz_next->ecc_info;
 291                                 tmp_prz->corrected_bytes +=
 292                                                 prz_next->corrected_bytes;
 293                                 tmp_prz->bad_blocks += prz_next->bad_blocks;
 294                                 size = ftrace_log_combine(tmp_prz, prz_next);
 295                                 if (size)
 296                                         goto out;
 297                         }
 298                         record->id = 0;
 299                 }
 300         }
 301
 302         if (!prz_ok(prz)) {
 303                 size = 0;
 304                 goto out;
 305         }
 306
 307         size = persistent_ram_old_size(prz) - header_length;
 308
 309         /* ECC correction notice */
 310         record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 311
 312         record->buf = kmalloc(size + record->ecc_notice_size + 1, GFP_KERNEL);
 313         if (record->buf == NULL) {
 314                 size = -ENOMEM;
 315                 goto out;
 316         }
 317
 318         memcpy(record->buf, (char *)persistent_ram_old(prz) + header_length,
 319                size);
 320
 321         persistent_ram_ecc_string(prz, record->buf + size,
 322                                   record->ecc_notice_size + 1);
 323
 324 out:
 325         if (free_prz) {
 326                 kfree(prz->old_log);
 327                 kfree(prz);
 328         }
 329
 330         return size;
 331 }
 332
 333 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 334                                      struct pstore_record *record)
 335 {
 336         char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
 337         size_t len;
 338
 339         len = scnprintf(hdr, sizeof(hdr),
 340                 RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
 341                 (time64_t)record->time.tv_sec,
 342                 record->time.tv_nsec / 1000,
 343                 record->compressed ? 'C' : 'D');
 344         persistent_ram_write(prz, hdr, len);
 345
 346         return len;
 347 }
 348
 349 static int notrace ramoops_pstore_write(struct pstore_record *record)
 350 {
 351         struct ramoops_context *cxt = record->psi->data;
 352         struct persistent_ram_zone *prz;
 353         size_t size, hlen;
 354
 355         if (record->type == PSTORE_TYPE_CONSOLE) {
 356                 if (!cxt->cprz)
 357                         return -ENOMEM;
 358                 persistent_ram_write(cxt->cprz, record->buf, record->size);
 359                 return 0;
 360         } else if (record->type == PSTORE_TYPE_FTRACE) {
 361                 int zonenum;
 362
 363                 if (!cxt->fprzs)
 364                         return -ENOMEM;
 365                 /*
 366                  * Choose zone by if we're using per-cpu buffers.
 367                  */
 368                 if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 369                         zonenum = smp_processor_id();
 370                 else
 371                         zonenum = 0;
 372
 373                 persistent_ram_write(cxt->fprzs[zonenum], record->buf,
 374                                      record->size);
 375                 return 0;
 376         } else if (record->type == PSTORE_TYPE_PMSG) {
 377                 pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__);
 378                 return -EINVAL;
 379         }
 380
 381         if (record->type != PSTORE_TYPE_DMESG)
 382                 return -EINVAL;
 383
 384         /*
 385          * Out of the various dmesg dump types, ramoops is currently designed
 386          * to only store crash logs, rather than storing general kernel logs.
 387          */
 388         if (record->reason != KMSG_DUMP_OOPS &&
 389             record->reason != KMSG_DUMP_PANIC)
 390                 return -EINVAL;
 391
 392         /* Skip Oopes when configured to do so. */
 393         if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 394                 return -EINVAL;
 395
 396         /*
 397          * Explicitly only take the first part of any new crash.
 398          * If our buffer is larger than kmsg_bytes, this can never happen,
 399          * and if our buffer is smaller than kmsg_bytes, we don't want the
 400          * report split across multiple records.
 401          */
 402         if (record->part != 1)
 403                 return -ENOSPC;
 404
 405         if (!cxt->dprzs)
 406                 return -ENOSPC;
 407
 408         prz = cxt->dprzs[cxt->dump_write_cnt];
 409
 410         /*
 411          * Since this is a new crash dump, we need to reset the buffer in
 412          * case it still has an old dump present. Without this, the new dump
 413          * will get appended, which would seriously confuse anything trying
 414          * to check dump file contents. Specifically, ramoops_read_kmsg_hdr()
 415          * expects to find a dump header in the beginning of buffer data, so
 416          * we must to reset the buffer values, in order to ensure that the
 417          * header will be written to the beginning of the buffer.
 418          */
 419         persistent_ram_zap(prz);
 420
 421         /* Build header and append record contents. */
 422         hlen = ramoops_write_kmsg_hdr(prz, record);
 423         if (!hlen)
 424                 return -ENOMEM;
 425
 426         size = record->size;
 427         if (size + hlen > prz->buffer_size)
 428                 size = prz->buffer_size - hlen;
 429         persistent_ram_write(prz, record->buf, size);
 430
 431         cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 432
 433         return 0;
 434 }
 435
 436 static int notrace ramoops_pstore_write_user(struct pstore_record *record,
 437                                              const char __user *buf)
 438 {
 439         if (record->type == PSTORE_TYPE_PMSG) {
 440                 struct ramoops_context *cxt = record->psi->data;
 441
 442                 if (!cxt->mprz)
 443                         return -ENOMEM;
 444                 return persistent_ram_write_user(cxt->mprz, buf, record->size);
 445         }
 446
 447         return -EINVAL;
 448 }
 449
 450 static int ramoops_pstore_erase(struct pstore_record *record)
 451 {
 452         struct ramoops_context *cxt = record->psi->data;
 453         struct persistent_ram_zone *prz;
 454
 455         switch (record->type) {
 456         case PSTORE_TYPE_DMESG:
 457                 if (record->id >= cxt->max_dump_cnt)
 458                         return -EINVAL;
 459                 prz = cxt->dprzs[record->id];
 460                 break;
 461         case PSTORE_TYPE_CONSOLE:
 462                 prz = cxt->cprz;
 463                 break;
 464         case PSTORE_TYPE_FTRACE:
 465                 if (record->id >= cxt->max_ftrace_cnt)
 466                         return -EINVAL;
 467                 prz = cxt->fprzs[record->id];
 468                 break;
 469         case PSTORE_TYPE_PMSG:
 470                 prz = cxt->mprz;
 471                 break;
 472         default:
 473                 return -EINVAL;
 474         }
 475
 476         persistent_ram_free_old(prz);
 477         persistent_ram_zap(prz);
 478
 479         return 0;
 480 }
 481
 482 static struct ramoops_context oops_cxt = {
 483         .pstore = {
 484                 .owner  = THIS_MODULE,
 485                 .name   = "ramoops",
 486                 .open   = ramoops_pstore_open,
 487                 .read   = ramoops_pstore_read,
 488                 .write  = ramoops_pstore_write,
 489                 .write_user     = ramoops_pstore_write_user,
 490                 .erase  = ramoops_pstore_erase,
 491         },
 492 };
 493
 494 static void ramoops_free_przs(struct ramoops_context *cxt)
 495 {
 496         int i;
 497
 498         /* Free dump PRZs */
 499         if (cxt->dprzs) {
 500                 for (i = 0; i < cxt->max_dump_cnt; i++)
 501                         persistent_ram_free(cxt->dprzs[i]);
 502
 503                 kfree(cxt->dprzs);
 504                 cxt->max_dump_cnt = 0;
 505         }
 506
 507         /* Free ftrace PRZs */
 508         if (cxt->fprzs) {
 509                 for (i = 0; i < cxt->max_ftrace_cnt; i++)
 510                         persistent_ram_free(cxt->fprzs[i]);
 511                 kfree(cxt->fprzs);
 512                 cxt->max_ftrace_cnt = 0;
 513         }
 514 }
 515
 516 static int ramoops_init_przs(const char *name,
 517                              struct device *dev, struct ramoops_context *cxt,
 518                              struct persistent_ram_zone ***przs,
 519                              phys_addr_t *paddr, size_t mem_sz,
 520                              ssize_t record_size,
 521                              unsigned int *cnt, u32 sig, u32 flags)
 522 {
 523         int err = -ENOMEM;
 524         int i;
 525         size_t zone_sz;
 526         struct persistent_ram_zone **prz_ar;
 527
 528         /* Allocate nothing for 0 mem_sz or 0 record_size. */
 529         if (mem_sz == 0 || record_size == 0) {
 530                 *cnt = 0;
 531                 return 0;
 532         }
 533
 534         /*
 535          * If we have a negative record size, calculate it based on
 536          * mem_sz / *cnt. If we have a positive record size, calculate
 537          * cnt from mem_sz / record_size.
 538          */
 539         if (record_size < 0) {
 540                 if (*cnt == 0)
 541                         return 0;
 542                 record_size = mem_sz / *cnt;
 543                 if (record_size == 0) {
 544                         dev_err(dev, "%s record size == 0 (%zu / %u)\n",
 545                                 name, mem_sz, *cnt);
 546                         goto fail;
 547                 }
 548         } else {
 549                 *cnt = mem_sz / record_size;
 550                 if (*cnt == 0) {
 551                         dev_err(dev, "%s record count == 0 (%zu / %zu)\n",
 552                                 name, mem_sz, record_size);
 553                         goto fail;
 554                 }
 555         }
 556
 557         if (*paddr + mem_sz - cxt->phys_addr > cxt->size) {
 558                 dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 559                         name,
 560                         mem_sz, (unsigned long long)*paddr,
 561                         cxt->size, (unsigned long long)cxt->phys_addr);
 562                 goto fail;
 563         }
 564
 565         zone_sz = mem_sz / *cnt;
 566         if (!zone_sz) {
 567                 dev_err(dev, "%s zone size == 0\n", name);
 568                 goto fail;
 569         }
 570
 571         prz_ar = kcalloc(*cnt, sizeof(**przs), GFP_KERNEL);
 572         if (!prz_ar)
 573                 goto fail;
 574
 575         for (i = 0; i < *cnt; i++) {
 576                 char *label;
 577
 578                 if (*cnt == 1)
 579                         label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 580                 else
 581                         label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
 582                                           name, i, *cnt - 1);
 583                 prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
 584                                                &cxt->ecc_info,
 585                                                cxt->memtype, flags, label);
 586                 kfree(label);
 587                 if (IS_ERR(prz_ar[i])) {
 588                         err = PTR_ERR(prz_ar[i]);
 589                         dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
 590                                 name, record_size,
 591                                 (unsigned long long)*paddr, err);
 592
 593                         while (i > 0) {
 594                                 i--;
 595                                 persistent_ram_free(prz_ar[i]);
 596                         }
 597                         kfree(prz_ar);
 598                         goto fail;
 599                 }
 600                 *paddr += zone_sz;
 601                 prz_ar[i]->type = pstore_name_to_type(name);
 602         }
 603
 604         *przs = prz_ar;
 605         return 0;
 606
 607 fail:
 608         *cnt = 0;
 609         return err;
 610 }
 611
 612 static int ramoops_init_prz(const char *name,
 613                             struct device *dev, struct ramoops_context *cxt,
 614                             struct persistent_ram_zone **prz,
 615                             phys_addr_t *paddr, size_t sz, u32 sig)
 616 {
 617         char *label;
 618
 619         if (!sz)
 620                 return 0;
 621
 622         if (*paddr + sz - cxt->phys_addr > cxt->size) {
 623                 dev_err(dev, "no room for %s mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 624                         name, sz, (unsigned long long)*paddr,
 625                         cxt->size, (unsigned long long)cxt->phys_addr);
 626                 return -ENOMEM;
 627         }
 628
 629         label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 630         *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
 631                                   cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
 632         kfree(label);
 633         if (IS_ERR(*prz)) {
 634                 int err = PTR_ERR(*prz);
 635
 636                 dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
 637                         name, sz, (unsigned long long)*paddr, err);
 638                 return err;
 639         }
 640
 641         *paddr += sz;
 642         (*prz)->type = pstore_name_to_type(name);
 643
 644         return 0;
 645 }
 646
 647 static int ramoops_parse_dt_size(struct platform_device *pdev,
 648                                  const char *propname, u32 *value)
 649 {
 650         u32 val32 = 0;
 651         int ret;
 652
 653         ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
 654         if (ret < 0 && ret != -EINVAL) {
 655                 dev_err(&pdev->dev, "failed to parse property %s: %d\n",
 656                         propname, ret);
 657                 return ret;
 658         }
 659
 660         if (val32 > INT_MAX) {
 661                 dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
 662                 return -EOVERFLOW;
 663         }
 664
 665         *value = val32;
 666         return 0;
 667 }
 668
 669 static int ramoops_parse_dt(struct platform_device *pdev,
 670                             struct ramoops_platform_data *pdata)
 671 {
 672         struct device_node *of_node = pdev->dev.of_node;
 673         struct device_node *parent_node;
 674         struct resource *res;
 675         u32 value;
 676         int ret;
 677
 678         dev_dbg(&pdev->dev, "using Device Tree\n");
 679
 680         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 681         if (!res) {
 682                 dev_err(&pdev->dev,
 683                         "failed to locate DT /reserved-memory resource\n");
 684                 return -EINVAL;
 685         }
 686
 687         pdata->mem_size = resource_size(res);
 688         pdata->mem_address = res->start;
 689         pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
 690         pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
 691
 692 #define parse_size(name, field) {                                       \
 693                 ret = ramoops_parse_dt_size(pdev, name, &value);        \
 694                 if (ret < 0)                                            \
 695                         return ret;                                     \
 696                 field = value;                                          \
 697         }
 698
 699         parse_size("record-size", pdata->record_size);
 700         parse_size("console-size", pdata->console_size);
 701         parse_size("ftrace-size", pdata->ftrace_size);
 702         parse_size("pmsg-size", pdata->pmsg_size);
 703         parse_size("ecc-size", pdata->ecc_info.ecc_size);
 704         parse_size("flags", pdata->flags);
 705
 706 #undef parse_size
 707
 708         /*
 709          * Some old Chromebooks relied on the kernel setting the
 710          * console_size and pmsg_size to the record size since that's
 711          * what the downstream kernel did.  These same Chromebooks had
 712          * "ramoops" straight under the root node which isn't
 713          * according to the current upstream bindings (though it was
 714          * arguably acceptable under a prior version of the bindings).
 715          * Let's make those old Chromebooks work by detecting that
 716          * we're not a child of "reserved-memory" and mimicking the
 717          * expected behavior.
 718          */
 719         parent_node = of_get_parent(of_node);
 720         if (!of_node_name_eq(parent_node, "reserved-memory") &&
 721             !pdata->console_size && !pdata->ftrace_size &&
 722             !pdata->pmsg_size && !pdata->ecc_info.ecc_size) {
 723                 pdata->console_size = pdata->record_size;
 724                 pdata->pmsg_size = pdata->record_size;
 725         }
 726         of_node_put(parent_node);
 727
 728         return 0;
 729 }
 730
 731 static int ramoops_probe(struct platform_device *pdev)
 732 {
 733         struct device *dev = &pdev->dev;
 734         struct ramoops_platform_data *pdata = dev->platform_data;
 735         struct ramoops_platform_data pdata_local;
 736         struct ramoops_context *cxt = &oops_cxt;
 737         size_t dump_mem_sz;
 738         phys_addr_t paddr;
 739         int err = -EINVAL;
 740
 741         /*
 742          * Only a single ramoops area allowed at a time, so fail extra
 743          * probes.
 744          */
 745         if (cxt->max_dump_cnt) {
 746                 pr_err("already initialized\n");
 747                 goto fail_out;
 748         }
 749
 750         if (dev_of_node(dev) && !pdata) {
 751                 pdata = &pdata_local;
 752                 memset(pdata, 0, sizeof(*pdata));
 753
 754                 err = ramoops_parse_dt(pdev, pdata);
 755                 if (err < 0)
 756                         goto fail_out;
 757         }
 758
 759         /* Make sure we didn't get bogus platform data pointer. */
 760         if (!pdata) {
 761                 pr_err("NULL platform data\n");
 762                 goto fail_out;
 763         }
 764
 765         if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 766                         !pdata->ftrace_size && !pdata->pmsg_size)) {
 767                 pr_err("The memory size and the record/console size must be "
 768                         "non-zero\n");
 769                 goto fail_out;
 770         }
 771
 772         if (pdata->record_size && !is_power_of_2(pdata->record_size))
 773                 pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 774         if (pdata->console_size && !is_power_of_2(pdata->console_size))
 775                 pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 776         if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
 777                 pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 778         if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
 779                 pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
 780
 781         cxt->size = pdata->mem_size;
 782         cxt->phys_addr = pdata->mem_address;
 783         cxt->memtype = pdata->mem_type;
 784         cxt->record_size = pdata->record_size;
 785         cxt->console_size = pdata->console_size;
 786         cxt->ftrace_size = pdata->ftrace_size;
 787         cxt->pmsg_size = pdata->pmsg_size;
 788         cxt->dump_oops = pdata->dump_oops;
 789         cxt->flags = pdata->flags;
 790         cxt->ecc_info = pdata->ecc_info;
 791
 792         paddr = cxt->phys_addr;
 793
 794         dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
 795                         - cxt->pmsg_size;
 796         err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
 797                                 dump_mem_sz, cxt->record_size,
 798                                 &cxt->max_dump_cnt, 0, 0);
 799         if (err)
 800                 goto fail_out;
 801
 802         err = ramoops_init_prz("console", dev, cxt, &cxt->cprz, &paddr,
 803                                cxt->console_size, 0);
 804         if (err)
 805                 goto fail_init_cprz;
 806
 807         cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 808                                 ? nr_cpu_ids
 809                                 : 1;
 810         err = ramoops_init_przs("ftrace", dev, cxt, &cxt->fprzs, &paddr,
 811                                 cxt->ftrace_size, -1,
 812                                 &cxt->max_ftrace_cnt, LINUX_VERSION_CODE,
 813                                 (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
 814                                         ? PRZ_FLAG_NO_LOCK : 0);
 815         if (err)
 816                 goto fail_init_fprz;
 817
 818         err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
 819                                 cxt->pmsg_size, 0);
 820         if (err)
 821                 goto fail_init_mprz;
 822
 823         cxt->pstore.data = cxt;
 824         /*
 825          * Prepare frontend flags based on which areas are initialized.
 826          * For ramoops_init_przs() cases, the "max count" variable tells
 827          * if there are regions present. For ramoops_init_prz() cases,
 828          * the single region size is how to check.
 829          */
 830         cxt->pstore.flags = 0;
 831         if (cxt->max_dump_cnt)
 832                 cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
 833         if (cxt->console_size)
 834                 cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
 835         if (cxt->max_ftrace_cnt)
 836                 cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
 837         if (cxt->pmsg_size)
 838                 cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
 839
 840         /*
 841          * Since bufsize is only used for dmesg crash dumps, it
 842          * must match the size of the dprz record (after PRZ header
 843          * and ECC bytes have been accounted for).
 844          */
 845         if (cxt->pstore.flags & PSTORE_FLAGS_DMESG) {
 846                 cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
 847                 cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
 848                 if (!cxt->pstore.buf) {
 849                         pr_err("cannot allocate pstore crash dump buffer\n");
 850                         err = -ENOMEM;
 851                         goto fail_clear;
 852                 }
 853         }
 854
 855         err = pstore_register(&cxt->pstore);
 856         if (err) {
 857                 pr_err("registering with pstore failed\n");
 858                 goto fail_buf;
 859         }
 860
 861         /*
 862          * Update the module parameter variables as well so they are visible
 863          * through /sys/module/ramoops/parameters/
 864          */
 865         mem_size = pdata->mem_size;
 866         mem_address = pdata->mem_address;
 867         record_size = pdata->record_size;
 868         dump_oops = pdata->dump_oops;
 869         ramoops_console_size = pdata->console_size;
 870         ramoops_pmsg_size = pdata->pmsg_size;
 871         ramoops_ftrace_size = pdata->ftrace_size;
 872
 873         pr_info("using 0x%lx@0x%llx, ecc: %d\n",
 874                 cxt->size, (unsigned long long)cxt->phys_addr,
 875                 cxt->ecc_info.ecc_size);
 876
 877         return 0;
 878
 879 fail_buf:
 880         kfree(cxt->pstore.buf);
 881 fail_clear:
 882         cxt->pstore.bufsize = 0;
 883         persistent_ram_free(cxt->mprz);
 884 fail_init_mprz:
 885 fail_init_fprz:
 886         persistent_ram_free(cxt->cprz);
 887 fail_init_cprz:
 888         ramoops_free_przs(cxt);
 889 fail_out:
 890         return err;
 891 }
 892
 893 static int ramoops_remove(struct platform_device *pdev)
 894 {
 895         struct ramoops_context *cxt = &oops_cxt;
 896
 897         pstore_unregister(&cxt->pstore);
 898
 899         kfree(cxt->pstore.buf);
 900         cxt->pstore.bufsize = 0;
 901
 902         persistent_ram_free(cxt->mprz);
 903         persistent_ram_free(cxt->cprz);
 904         ramoops_free_przs(cxt);
 905
 906         return 0;
 907 }
 908
 909 static const struct of_device_id dt_match[] = {
 910         { .compatible = "ramoops" },
 911         {}
 912 };
 913
 914 static struct platform_driver ramoops_driver = {
 915         .probe          = ramoops_probe,
 916         .remove         = ramoops_remove,
 917         .driver         = {
 918                 .name           = "ramoops",
 919                 .of_match_table = dt_match,
 920         },
 921 };
 922
 923 static inline void ramoops_unregister_dummy(void)
 924 {
 925         platform_device_unregister(dummy);
 926         dummy = NULL;
 927 }
 928
 929 static void __init ramoops_register_dummy(void)
 930 {
 931         struct ramoops_platform_data pdata;
 932
 933         /*
 934          * Prepare a dummy platform data structure to carry the module
 935          * parameters. If mem_size isn't set, then there are no module
 936          * parameters, and we can skip this.
 937          */
 938         if (!mem_size)
 939                 return;
 940
 941         pr_info("using module parameters\n");
 942
 943         memset(&pdata, 0, sizeof(pdata));
 944         pdata.mem_size = mem_size;
 945         pdata.mem_address = mem_address;
 946         pdata.mem_type = mem_type;
 947         pdata.record_size = record_size;
 948         pdata.console_size = ramoops_console_size;
 949         pdata.ftrace_size = ramoops_ftrace_size;
 950         pdata.pmsg_size = ramoops_pmsg_size;
 951         pdata.dump_oops = dump_oops;
 952         pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
 953
 954         /*
 955          * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 956          * (using 1 byte for ECC isn't much of use anyway).
 957          */
 958         pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 959
 960         dummy = platform_device_register_data(NULL, "ramoops", -1,
 961                         &pdata, sizeof(pdata));
 962         if (IS_ERR(dummy)) {
 963                 pr_info("could not create platform device: %ld\n",
 964                         PTR_ERR(dummy));
 965                 dummy = NULL;
 966                 ramoops_unregister_dummy();
 967         }
 968 }
 969
 970 static int __init ramoops_init(void)
 971 {
 972         int ret;
 973
 974         ramoops_register_dummy();
 975         ret = platform_driver_register(&ramoops_driver);
 976         if (ret != 0)
 977                 ramoops_unregister_dummy();
 978
 979         return ret;
 980 }
 981 postcore_initcall(ramoops_init);
 982
 983 static void __exit ramoops_exit(void)
 984 {
 985         platform_driver_unregister(&ramoops_driver);
 986         ramoops_unregister_dummy();
 987 }
 988 module_exit(ramoops_exit);
 989
 990 MODULE_LICENSE("GPL");
 991 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 992 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");