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