linux/arch/powerpc/kernel/fadump.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Firmware Assisted dump: A robust mechanism to get reliable kernel crash
   4 * dump with assistance from firmware. This approach does not use kexec,
   5 * instead firmware assists in booting the kdump kernel while preserving
   6 * memory contents. The most of the code implementation has been adapted
   7 * from phyp assisted dump implementation written by Linas Vepstas and
   8 * Manish Ahuja
   9 *
  10 * Copyright 2011 IBM Corporation
  11 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
  12 */
  13
  14#undef DEBUG
  15#define pr_fmt(fmt) "fadump: " fmt
  16
  17#include <linux/string.h>
  18#include <linux/memblock.h>
  19#include <linux/delay.h>
  20#include <linux/seq_file.h>
  21#include <linux/crash_dump.h>
  22#include <linux/kobject.h>
  23#include <linux/sysfs.h>
  24#include <linux/slab.h>
  25#include <linux/cma.h>
  26#include <linux/hugetlb.h>
  27
  28#include <asm/debugfs.h>
  29#include <asm/page.h>
  30#include <asm/prom.h>
  31#include <asm/fadump.h>
  32#include <asm/fadump-internal.h>
  33#include <asm/setup.h>
  34#include <asm/interrupt.h>
  35
  36/*
  37 * The CPU who acquired the lock to trigger the fadump crash should
  38 * wait for other CPUs to enter.
  39 *
  40 * The timeout is in milliseconds.
  41 */
  42#define CRASH_TIMEOUT           500
  43
  44static struct fw_dump fw_dump;
  45
  46static void __init fadump_reserve_crash_area(u64 base);
  47
  48#ifndef CONFIG_PRESERVE_FA_DUMP
  49
  50static struct kobject *fadump_kobj;
  51
  52static atomic_t cpus_in_fadump;
  53static DEFINE_MUTEX(fadump_mutex);
  54
  55static struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0, false };
  56
  57#define RESERVED_RNGS_SZ        16384 /* 16K - 128 entries */
  58#define RESERVED_RNGS_CNT       (RESERVED_RNGS_SZ / \
  59                                 sizeof(struct fadump_memory_range))
  60static struct fadump_memory_range rngs[RESERVED_RNGS_CNT];
  61static struct fadump_mrange_info
  62reserved_mrange_info = { "reserved", rngs, RESERVED_RNGS_SZ, 0, RESERVED_RNGS_CNT, true };
  63
  64static void __init early_init_dt_scan_reserved_ranges(unsigned long node);
  65
  66#ifdef CONFIG_CMA
  67static struct cma *fadump_cma;
  68
  69/*
  70 * fadump_cma_init() - Initialize CMA area from a fadump reserved memory
  71 *
  72 * This function initializes CMA area from fadump reserved memory.
  73 * The total size of fadump reserved memory covers for boot memory size
  74 * + cpu data size + hpte size and metadata.
  75 * Initialize only the area equivalent to boot memory size for CMA use.
  76 * The reamining portion of fadump reserved memory will be not given
  77 * to CMA and pages for thoes will stay reserved. boot memory size is
  78 * aligned per CMA requirement to satisy cma_init_reserved_mem() call.
  79 * But for some reason even if it fails we still have the memory reservation
  80 * with us and we can still continue doing fadump.
  81 */
  82static int __init fadump_cma_init(void)
  83{
  84        unsigned long long base, size;
  85        int rc;
  86
  87        if (!fw_dump.fadump_enabled)
  88                return 0;
  89
  90        /*
  91         * Do not use CMA if user has provided fadump=nocma kernel parameter.
  92         * Return 1 to continue with fadump old behaviour.
  93         */
  94        if (fw_dump.nocma)
  95                return 1;
  96
  97        base = fw_dump.reserve_dump_area_start;
  98        size = fw_dump.boot_memory_size;
  99
 100        if (!size)
 101                return 0;
 102
 103        rc = cma_init_reserved_mem(base, size, 0, "fadump_cma", &fadump_cma);
 104        if (rc) {
 105                pr_err("Failed to init cma area for firmware-assisted dump,%d\n", rc);
 106                /*
 107                 * Though the CMA init has failed we still have memory
 108                 * reservation with us. The reserved memory will be
 109                 * blocked from production system usage.  Hence return 1,
 110                 * so that we can continue with fadump.
 111                 */
 112                return 1;
 113        }
 114
 115        /*
 116         * So we now have successfully initialized cma area for fadump.
 117         */
 118        pr_info("Initialized 0x%lx bytes cma area at %ldMB from 0x%lx "
 119                "bytes of memory reserved for firmware-assisted dump\n",
 120                cma_get_size(fadump_cma),
 121                (unsigned long)cma_get_base(fadump_cma) >> 20,
 122                fw_dump.reserve_dump_area_size);
 123        return 1;
 124}
 125#else
 126static int __init fadump_cma_init(void) { return 1; }
 127#endif /* CONFIG_CMA */
 128
 129/* Scan the Firmware Assisted dump configuration details. */
 130int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
 131                                      int depth, void *data)
 132{
 133        if (depth == 0) {
 134                early_init_dt_scan_reserved_ranges(node);
 135                return 0;
 136        }
 137
 138        if (depth != 1)
 139                return 0;
 140
 141        if (strcmp(uname, "rtas") == 0) {
 142                rtas_fadump_dt_scan(&fw_dump, node);
 143                return 1;
 144        }
 145
 146        if (strcmp(uname, "ibm,opal") == 0) {
 147                opal_fadump_dt_scan(&fw_dump, node);
 148                return 1;
 149        }
 150
 151        return 0;
 152}
 153
 154/*
 155 * If fadump is registered, check if the memory provided
 156 * falls within boot memory area and reserved memory area.
 157 */
 158int is_fadump_memory_area(u64 addr, unsigned long size)
 159{
 160        u64 d_start, d_end;
 161
 162        if (!fw_dump.dump_registered)
 163                return 0;
 164
 165        if (!size)
 166                return 0;
 167
 168        d_start = fw_dump.reserve_dump_area_start;
 169        d_end = d_start + fw_dump.reserve_dump_area_size;
 170        if (((addr + size) > d_start) && (addr <= d_end))
 171                return 1;
 172
 173        return (addr <= fw_dump.boot_mem_top);
 174}
 175
 176int should_fadump_crash(void)
 177{
 178        if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
 179                return 0;
 180        return 1;
 181}
 182
 183int is_fadump_active(void)
 184{
 185        return fw_dump.dump_active;
 186}
 187
 188/*
 189 * Returns true, if there are no holes in memory area between d_start to d_end,
 190 * false otherwise.
 191 */
 192static bool is_fadump_mem_area_contiguous(u64 d_start, u64 d_end)
 193{
 194        phys_addr_t reg_start, reg_end;
 195        bool ret = false;
 196        u64 i, start, end;
 197
 198        for_each_mem_range(i, &reg_start, &reg_end) {
 199                start = max_t(u64, d_start, reg_start);
 200                end = min_t(u64, d_end, reg_end);
 201                if (d_start < end) {
 202                        /* Memory hole from d_start to start */
 203                        if (start > d_start)
 204                                break;
 205
 206                        if (end == d_end) {
 207                                ret = true;
 208                                break;
 209                        }
 210
 211                        d_start = end + 1;
 212                }
 213        }
 214
 215        return ret;
 216}
 217
 218/*
 219 * Returns true, if there are no holes in boot memory area,
 220 * false otherwise.
 221 */
 222bool is_fadump_boot_mem_contiguous(void)
 223{
 224        unsigned long d_start, d_end;
 225        bool ret = false;
 226        int i;
 227
 228        for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
 229                d_start = fw_dump.boot_mem_addr[i];
 230                d_end   = d_start + fw_dump.boot_mem_sz[i];
 231
 232                ret = is_fadump_mem_area_contiguous(d_start, d_end);
 233                if (!ret)
 234                        break;
 235        }
 236
 237        return ret;
 238}
 239
 240/*
 241 * Returns true, if there are no holes in reserved memory area,
 242 * false otherwise.
 243 */
 244bool is_fadump_reserved_mem_contiguous(void)
 245{
 246        u64 d_start, d_end;
 247
 248        d_start = fw_dump.reserve_dump_area_start;
 249        d_end   = d_start + fw_dump.reserve_dump_area_size;
 250        return is_fadump_mem_area_contiguous(d_start, d_end);
 251}
 252
 253/* Print firmware assisted dump configurations for debugging purpose. */
 254static void fadump_show_config(void)
 255{
 256        int i;
 257
 258        pr_debug("Support for firmware-assisted dump (fadump): %s\n",
 259                        (fw_dump.fadump_supported ? "present" : "no support"));
 260
 261        if (!fw_dump.fadump_supported)
 262                return;
 263
 264        pr_debug("Fadump enabled    : %s\n",
 265                                (fw_dump.fadump_enabled ? "yes" : "no"));
 266        pr_debug("Dump Active       : %s\n",
 267                                (fw_dump.dump_active ? "yes" : "no"));
 268        pr_debug("Dump section sizes:\n");
 269        pr_debug("    CPU state data size: %lx\n", fw_dump.cpu_state_data_size);
 270        pr_debug("    HPTE region size   : %lx\n", fw_dump.hpte_region_size);
 271        pr_debug("    Boot memory size   : %lx\n", fw_dump.boot_memory_size);
 272        pr_debug("    Boot memory top    : %llx\n", fw_dump.boot_mem_top);
 273        pr_debug("Boot memory regions cnt: %llx\n", fw_dump.boot_mem_regs_cnt);
 274        for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
 275                pr_debug("[%03d] base = %llx, size = %llx\n", i,
 276                         fw_dump.boot_mem_addr[i], fw_dump.boot_mem_sz[i]);
 277        }
 278}
 279
 280/**
 281 * fadump_calculate_reserve_size(): reserve variable boot area 5% of System RAM
 282 *
 283 * Function to find the largest memory size we need to reserve during early
 284 * boot process. This will be the size of the memory that is required for a
 285 * kernel to boot successfully.
 286 *
 287 * This function has been taken from phyp-assisted dump feature implementation.
 288 *
 289 * returns larger of 256MB or 5% rounded down to multiples of 256MB.
 290 *
 291 * TODO: Come up with better approach to find out more accurate memory size
 292 * that is required for a kernel to boot successfully.
 293 *
 294 */
 295static __init u64 fadump_calculate_reserve_size(void)
 296{
 297        u64 base, size, bootmem_min;
 298        int ret;
 299
 300        if (fw_dump.reserve_bootvar)
 301                pr_warn("'fadump_reserve_mem=' parameter is deprecated in favor of 'crashkernel=' parameter.\n");
 302
 303        /*
 304         * Check if the size is specified through crashkernel= cmdline
 305         * option. If yes, then use that but ignore base as fadump reserves
 306         * memory at a predefined offset.
 307         */
 308        ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
 309                                &size, &base);
 310        if (ret == 0 && size > 0) {
 311                unsigned long max_size;
 312
 313                if (fw_dump.reserve_bootvar)
 314                        pr_info("Using 'crashkernel=' parameter for memory reservation.\n");
 315
 316                fw_dump.reserve_bootvar = (unsigned long)size;
 317
 318                /*
 319                 * Adjust if the boot memory size specified is above
 320                 * the upper limit.
 321                 */
 322                max_size = memblock_phys_mem_size() / MAX_BOOT_MEM_RATIO;
 323                if (fw_dump.reserve_bootvar > max_size) {
 324                        fw_dump.reserve_bootvar = max_size;
 325                        pr_info("Adjusted boot memory size to %luMB\n",
 326                                (fw_dump.reserve_bootvar >> 20));
 327                }
 328
 329                return fw_dump.reserve_bootvar;
 330        } else if (fw_dump.reserve_bootvar) {
 331                /*
 332                 * 'fadump_reserve_mem=' is being used to reserve memory
 333                 * for firmware-assisted dump.
 334                 */
 335                return fw_dump.reserve_bootvar;
 336        }
 337
 338        /* divide by 20 to get 5% of value */
 339        size = memblock_phys_mem_size() / 20;
 340
 341        /* round it down in multiples of 256 */
 342        size = size & ~0x0FFFFFFFUL;
 343
 344        /* Truncate to memory_limit. We don't want to over reserve the memory.*/
 345        if (memory_limit && size > memory_limit)
 346                size = memory_limit;
 347
 348        bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
 349        return (size > bootmem_min ? size : bootmem_min);
 350}
 351
 352/*
 353 * Calculate the total memory size required to be reserved for
 354 * firmware-assisted dump registration.
 355 */
 356static unsigned long get_fadump_area_size(void)
 357{
 358        unsigned long size = 0;
 359
 360        size += fw_dump.cpu_state_data_size;
 361        size += fw_dump.hpte_region_size;
 362        size += fw_dump.boot_memory_size;
 363        size += sizeof(struct fadump_crash_info_header);
 364        size += sizeof(struct elfhdr); /* ELF core header.*/
 365        size += sizeof(struct elf_phdr); /* place holder for cpu notes */
 366        /* Program headers for crash memory regions. */
 367        size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
 368
 369        size = PAGE_ALIGN(size);
 370
 371        /* This is to hold kernel metadata on platforms that support it */
 372        size += (fw_dump.ops->fadump_get_metadata_size ?
 373                 fw_dump.ops->fadump_get_metadata_size() : 0);
 374        return size;
 375}
 376
 377static int __init add_boot_mem_region(unsigned long rstart,
 378                                      unsigned long rsize)
 379{
 380        int i = fw_dump.boot_mem_regs_cnt++;
 381
 382        if (fw_dump.boot_mem_regs_cnt > FADUMP_MAX_MEM_REGS) {
 383                fw_dump.boot_mem_regs_cnt = FADUMP_MAX_MEM_REGS;
 384                return 0;
 385        }
 386
 387        pr_debug("Added boot memory range[%d] [%#016lx-%#016lx)\n",
 388                 i, rstart, (rstart + rsize));
 389        fw_dump.boot_mem_addr[i] = rstart;
 390        fw_dump.boot_mem_sz[i] = rsize;
 391        return 1;
 392}
 393
 394/*
 395 * Firmware usually has a hard limit on the data it can copy per region.
 396 * Honour that by splitting a memory range into multiple regions.
 397 */
 398static int __init add_boot_mem_regions(unsigned long mstart,
 399                                       unsigned long msize)
 400{
 401        unsigned long rstart, rsize, max_size;
 402        int ret = 1;
 403
 404        rstart = mstart;
 405        max_size = fw_dump.max_copy_size ? fw_dump.max_copy_size : msize;
 406        while (msize) {
 407                if (msize > max_size)
 408                        rsize = max_size;
 409                else
 410                        rsize = msize;
 411
 412                ret = add_boot_mem_region(rstart, rsize);
 413                if (!ret)
 414                        break;
 415
 416                msize -= rsize;
 417                rstart += rsize;
 418        }
 419
 420        return ret;
 421}
 422
 423static int __init fadump_get_boot_mem_regions(void)
 424{
 425        unsigned long size, cur_size, hole_size, last_end;
 426        unsigned long mem_size = fw_dump.boot_memory_size;
 427        phys_addr_t reg_start, reg_end;
 428        int ret = 1;
 429        u64 i;
 430
 431        fw_dump.boot_mem_regs_cnt = 0;
 432
 433        last_end = 0;
 434        hole_size = 0;
 435        cur_size = 0;
 436        for_each_mem_range(i, &reg_start, &reg_end) {
 437                size = reg_end - reg_start;
 438                hole_size += (reg_start - last_end);
 439
 440                if ((cur_size + size) >= mem_size) {
 441                        size = (mem_size - cur_size);
 442                        ret = add_boot_mem_regions(reg_start, size);
 443                        break;
 444                }
 445
 446                mem_size -= size;
 447                cur_size += size;
 448                ret = add_boot_mem_regions(reg_start, size);
 449                if (!ret)
 450                        break;
 451
 452                last_end = reg_end;
 453        }
 454        fw_dump.boot_mem_top = PAGE_ALIGN(fw_dump.boot_memory_size + hole_size);
 455
 456        return ret;
 457}
 458
 459/*
 460 * Returns true, if the given range overlaps with reserved memory ranges
 461 * starting at idx. Also, updates idx to index of overlapping memory range
 462 * with the given memory range.
 463 * False, otherwise.
 464 */
 465static bool overlaps_reserved_ranges(u64 base, u64 end, int *idx)
 466{
 467        bool ret = false;
 468        int i;
 469
 470        for (i = *idx; i < reserved_mrange_info.mem_range_cnt; i++) {
 471                u64 rbase = reserved_mrange_info.mem_ranges[i].base;
 472                u64 rend = rbase + reserved_mrange_info.mem_ranges[i].size;
 473
 474                if (end <= rbase)
 475                        break;
 476
 477                if ((end > rbase) &&  (base < rend)) {
 478                        *idx = i;
 479                        ret = true;
 480                        break;
 481                }
 482        }
 483
 484        return ret;
 485}
 486
 487/*
 488 * Locate a suitable memory area to reserve memory for FADump. While at it,
 489 * lookup reserved-ranges & avoid overlap with them, as they are used by F/W.
 490 */
 491static u64 __init fadump_locate_reserve_mem(u64 base, u64 size)
 492{
 493        struct fadump_memory_range *mrngs;
 494        phys_addr_t mstart, mend;
 495        int idx = 0;
 496        u64 i, ret = 0;
 497
 498        mrngs = reserved_mrange_info.mem_ranges;
 499        for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 500                                &mstart, &mend, NULL) {
 501                pr_debug("%llu) mstart: %llx, mend: %llx, base: %llx\n",
 502                         i, mstart, mend, base);
 503
 504                if (mstart > base)
 505                        base = PAGE_ALIGN(mstart);
 506
 507                while ((mend > base) && ((mend - base) >= size)) {
 508                        if (!overlaps_reserved_ranges(base, base+size, &idx)) {
 509                                ret = base;
 510                                goto out;
 511                        }
 512
 513                        base = mrngs[idx].base + mrngs[idx].size;
 514                        base = PAGE_ALIGN(base);
 515                }
 516        }
 517
 518out:
 519        return ret;
 520}
 521
 522int __init fadump_reserve_mem(void)
 523{
 524        u64 base, size, mem_boundary, bootmem_min;
 525        int ret = 1;
 526
 527        if (!fw_dump.fadump_enabled)
 528                return 0;
 529
 530        if (!fw_dump.fadump_supported) {
 531                pr_info("Firmware-Assisted Dump is not supported on this hardware\n");
 532                goto error_out;
 533        }
 534
 535        /*
 536         * Initialize boot memory size
 537         * If dump is active then we have already calculated the size during
 538         * first kernel.
 539         */
 540        if (!fw_dump.dump_active) {
 541                fw_dump.boot_memory_size =
 542                        PAGE_ALIGN(fadump_calculate_reserve_size());
 543#ifdef CONFIG_CMA
 544                if (!fw_dump.nocma) {
 545                        fw_dump.boot_memory_size =
 546                                ALIGN(fw_dump.boot_memory_size,
 547                                      FADUMP_CMA_ALIGNMENT);
 548                }
 549#endif
 550
 551                bootmem_min = fw_dump.ops->fadump_get_bootmem_min();
 552                if (fw_dump.boot_memory_size < bootmem_min) {
 553                        pr_err("Can't enable fadump with boot memory size (0x%lx) less than 0x%llx\n",
 554                               fw_dump.boot_memory_size, bootmem_min);
 555                        goto error_out;
 556                }
 557
 558                if (!fadump_get_boot_mem_regions()) {
 559                        pr_err("Too many holes in boot memory area to enable fadump\n");
 560                        goto error_out;
 561                }
 562        }
 563
 564        /*
 565         * Calculate the memory boundary.
 566         * If memory_limit is less than actual memory boundary then reserve
 567         * the memory for fadump beyond the memory_limit and adjust the
 568         * memory_limit accordingly, so that the running kernel can run with
 569         * specified memory_limit.
 570         */
 571        if (memory_limit && memory_limit < memblock_end_of_DRAM()) {
 572                size = get_fadump_area_size();
 573                if ((memory_limit + size) < memblock_end_of_DRAM())
 574                        memory_limit += size;
 575                else
 576                        memory_limit = memblock_end_of_DRAM();
 577                printk(KERN_INFO "Adjusted memory_limit for firmware-assisted"
 578                                " dump, now %#016llx\n", memory_limit);
 579        }
 580        if (memory_limit)
 581                mem_boundary = memory_limit;
 582        else
 583                mem_boundary = memblock_end_of_DRAM();
 584
 585        base = fw_dump.boot_mem_top;
 586        size = get_fadump_area_size();
 587        fw_dump.reserve_dump_area_size = size;
 588        if (fw_dump.dump_active) {
 589                pr_info("Firmware-assisted dump is active.\n");
 590
 591#ifdef CONFIG_HUGETLB_PAGE
 592                /*
 593                 * FADump capture kernel doesn't care much about hugepages.
 594                 * In fact, handling hugepages in capture kernel is asking for
 595                 * trouble. So, disable HugeTLB support when fadump is active.
 596                 */
 597                hugetlb_disabled = true;
 598#endif
 599                /*
 600                 * If last boot has crashed then reserve all the memory
 601                 * above boot memory size so that we don't touch it until
 602                 * dump is written to disk by userspace tool. This memory
 603                 * can be released for general use by invalidating fadump.
 604                 */
 605                fadump_reserve_crash_area(base);
 606
 607                pr_debug("fadumphdr_addr = %#016lx\n", fw_dump.fadumphdr_addr);
 608                pr_debug("Reserve dump area start address: 0x%lx\n",
 609                         fw_dump.reserve_dump_area_start);
 610        } else {
 611                /*
 612                 * Reserve memory at an offset closer to bottom of the RAM to
 613                 * minimize the impact of memory hot-remove operation.
 614                 */
 615                base = fadump_locate_reserve_mem(base, size);
 616
 617                if (!base || (base + size > mem_boundary)) {
 618                        pr_err("Failed to find memory chunk for reservation!\n");
 619                        goto error_out;
 620                }
 621                fw_dump.reserve_dump_area_start = base;
 622
 623                /*
 624                 * Calculate the kernel metadata address and register it with
 625                 * f/w if the platform supports.
 626                 */
 627                if (fw_dump.ops->fadump_setup_metadata &&
 628                    (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
 629                        goto error_out;
 630
 631                if (memblock_reserve(base, size)) {
 632                        pr_err("Failed to reserve memory!\n");
 633                        goto error_out;
 634                }
 635
 636                pr_info("Reserved %lldMB of memory at %#016llx (System RAM: %lldMB)\n",
 637                        (size >> 20), base, (memblock_phys_mem_size() >> 20));
 638
 639                ret = fadump_cma_init();
 640        }
 641
 642        return ret;
 643error_out:
 644        fw_dump.fadump_enabled = 0;
 645        return 0;
 646}
 647
 648/* Look for fadump= cmdline option. */
 649static int __init early_fadump_param(char *p)
 650{
 651        if (!p)
 652                return 1;
 653
 654        if (strncmp(p, "on", 2) == 0)
 655                fw_dump.fadump_enabled = 1;
 656        else if (strncmp(p, "off", 3) == 0)
 657                fw_dump.fadump_enabled = 0;
 658        else if (strncmp(p, "nocma", 5) == 0) {
 659                fw_dump.fadump_enabled = 1;
 660                fw_dump.nocma = 1;
 661        }
 662
 663        return 0;
 664}
 665early_param("fadump", early_fadump_param);
 666
 667/*
 668 * Look for fadump_reserve_mem= cmdline option
 669 * TODO: Remove references to 'fadump_reserve_mem=' parameter,
 670 *       the sooner 'crashkernel=' parameter is accustomed to.
 671 */
 672static int __init early_fadump_reserve_mem(char *p)
 673{
 674        if (p)
 675                fw_dump.reserve_bootvar = memparse(p, &p);
 676        return 0;
 677}
 678early_param("fadump_reserve_mem", early_fadump_reserve_mem);
 679
 680void crash_fadump(struct pt_regs *regs, const char *str)
 681{
 682        unsigned int msecs;
 683        struct fadump_crash_info_header *fdh = NULL;
 684        int old_cpu, this_cpu;
 685        /* Do not include first CPU */
 686        unsigned int ncpus = num_online_cpus() - 1;
 687
 688        if (!should_fadump_crash())
 689                return;
 690
 691        /*
 692         * old_cpu == -1 means this is the first CPU which has come here,
 693         * go ahead and trigger fadump.
 694         *
 695         * old_cpu != -1 means some other CPU has already on it's way
 696         * to trigger fadump, just keep looping here.
 697         */
 698        this_cpu = smp_processor_id();
 699        old_cpu = cmpxchg(&crashing_cpu, -1, this_cpu);
 700
 701        if (old_cpu != -1) {
 702                atomic_inc(&cpus_in_fadump);
 703
 704                /*
 705                 * We can't loop here indefinitely. Wait as long as fadump
 706                 * is in force. If we race with fadump un-registration this
 707                 * loop will break and then we go down to normal panic path
 708                 * and reboot. If fadump is in force the first crashing
 709                 * cpu will definitely trigger fadump.
 710                 */
 711                while (fw_dump.dump_registered)
 712                        cpu_relax();
 713                return;
 714        }
 715
 716        fdh = __va(fw_dump.fadumphdr_addr);
 717        fdh->crashing_cpu = crashing_cpu;
 718        crash_save_vmcoreinfo();
 719
 720        if (regs)
 721                fdh->regs = *regs;
 722        else
 723                ppc_save_regs(&fdh->regs);
 724
 725        fdh->online_mask = *cpu_online_mask;
 726
 727        /*
 728         * If we came in via system reset, wait a while for the secondary
 729         * CPUs to enter.
 730         */
 731        if (TRAP(&(fdh->regs)) == INTERRUPT_SYSTEM_RESET) {
 732                msecs = CRASH_TIMEOUT;
 733                while ((atomic_read(&cpus_in_fadump) < ncpus) && (--msecs > 0))
 734                        mdelay(1);
 735        }
 736
 737        fw_dump.ops->fadump_trigger(fdh, str);
 738}
 739
 740u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
 741{
 742        struct elf_prstatus prstatus;
 743
 744        memset(&prstatus, 0, sizeof(prstatus));
 745        /*
 746         * FIXME: How do i get PID? Do I really need it?
 747         * prstatus.pr_pid = ????
 748         */
 749        elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
 750        buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
 751                              &prstatus, sizeof(prstatus));
 752        return buf;
 753}
 754
 755void fadump_update_elfcore_header(char *bufp)
 756{
 757        struct elf_phdr *phdr;
 758
 759        bufp += sizeof(struct elfhdr);
 760
 761        /* First note is a place holder for cpu notes info. */
 762        phdr = (struct elf_phdr *)bufp;
 763
 764        if (phdr->p_type == PT_NOTE) {
 765                phdr->p_paddr   = __pa(fw_dump.cpu_notes_buf_vaddr);
 766                phdr->p_offset  = phdr->p_paddr;
 767                phdr->p_filesz  = fw_dump.cpu_notes_buf_size;
 768                phdr->p_memsz = fw_dump.cpu_notes_buf_size;
 769        }
 770        return;
 771}
 772
 773static void *fadump_alloc_buffer(unsigned long size)
 774{
 775        unsigned long count, i;
 776        struct page *page;
 777        void *vaddr;
 778
 779        vaddr = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
 780        if (!vaddr)
 781                return NULL;
 782
 783        count = PAGE_ALIGN(size) / PAGE_SIZE;
 784        page = virt_to_page(vaddr);
 785        for (i = 0; i < count; i++)
 786                mark_page_reserved(page + i);
 787        return vaddr;
 788}
 789
 790static void fadump_free_buffer(unsigned long vaddr, unsigned long size)
 791{
 792        free_reserved_area((void *)vaddr, (void *)(vaddr + size), -1, NULL);
 793}
 794
 795s32 fadump_setup_cpu_notes_buf(u32 num_cpus)
 796{
 797        /* Allocate buffer to hold cpu crash notes. */
 798        fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
 799        fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
 800        fw_dump.cpu_notes_buf_vaddr =
 801                (unsigned long)fadump_alloc_buffer(fw_dump.cpu_notes_buf_size);
 802        if (!fw_dump.cpu_notes_buf_vaddr) {
 803                pr_err("Failed to allocate %ld bytes for CPU notes buffer\n",
 804                       fw_dump.cpu_notes_buf_size);
 805                return -ENOMEM;
 806        }
 807
 808        pr_debug("Allocated buffer for cpu notes of size %ld at 0x%lx\n",
 809                 fw_dump.cpu_notes_buf_size,
 810                 fw_dump.cpu_notes_buf_vaddr);
 811        return 0;
 812}
 813
 814void fadump_free_cpu_notes_buf(void)
 815{
 816        if (!fw_dump.cpu_notes_buf_vaddr)
 817                return;
 818
 819        fadump_free_buffer(fw_dump.cpu_notes_buf_vaddr,
 820                           fw_dump.cpu_notes_buf_size);
 821        fw_dump.cpu_notes_buf_vaddr = 0;
 822        fw_dump.cpu_notes_buf_size = 0;
 823}
 824
 825static void fadump_free_mem_ranges(struct fadump_mrange_info *mrange_info)
 826{
 827        if (mrange_info->is_static) {
 828                mrange_info->mem_range_cnt = 0;
 829                return;
 830        }
 831
 832        kfree(mrange_info->mem_ranges);
 833        memset((void *)((u64)mrange_info + RNG_NAME_SZ), 0,
 834               (sizeof(struct fadump_mrange_info) - RNG_NAME_SZ));
 835}
 836
 837/*
 838 * Allocate or reallocate mem_ranges array in incremental units
 839 * of PAGE_SIZE.
 840 */
 841static int fadump_alloc_mem_ranges(struct fadump_mrange_info *mrange_info)
 842{
 843        struct fadump_memory_range *new_array;
 844        u64 new_size;
 845
 846        new_size = mrange_info->mem_ranges_sz + PAGE_SIZE;
 847        pr_debug("Allocating %llu bytes of memory for %s memory ranges\n",
 848                 new_size, mrange_info->name);
 849
 850        new_array = krealloc(mrange_info->mem_ranges, new_size, GFP_KERNEL);
 851        if (new_array == NULL) {
 852                pr_err("Insufficient memory for setting up %s memory ranges\n",
 853                       mrange_info->name);
 854                fadump_free_mem_ranges(mrange_info);
 855                return -ENOMEM;
 856        }
 857
 858        mrange_info->mem_ranges = new_array;
 859        mrange_info->mem_ranges_sz = new_size;
 860        mrange_info->max_mem_ranges = (new_size /
 861                                       sizeof(struct fadump_memory_range));
 862        return 0;
 863}
 864
 865static inline int fadump_add_mem_range(struct fadump_mrange_info *mrange_info,
 866                                       u64 base, u64 end)
 867{
 868        struct fadump_memory_range *mem_ranges = mrange_info->mem_ranges;
 869        bool is_adjacent = false;
 870        u64 start, size;
 871
 872        if (base == end)
 873                return 0;
 874
 875        /*
 876         * Fold adjacent memory ranges to bring down the memory ranges/
 877         * PT_LOAD segments count.
 878         */
 879        if (mrange_info->mem_range_cnt) {
 880                start = mem_ranges[mrange_info->mem_range_cnt - 1].base;
 881                size  = mem_ranges[mrange_info->mem_range_cnt - 1].size;
 882
 883                if ((start + size) == base)
 884                        is_adjacent = true;
 885        }
 886        if (!is_adjacent) {
 887                /* resize the array on reaching the limit */
 888                if (mrange_info->mem_range_cnt == mrange_info->max_mem_ranges) {
 889                        int ret;
 890
 891                        if (mrange_info->is_static) {
 892                                pr_err("Reached array size limit for %s memory ranges\n",
 893                                       mrange_info->name);
 894                                return -ENOSPC;
 895                        }
 896
 897                        ret = fadump_alloc_mem_ranges(mrange_info);
 898                        if (ret)
 899                                return ret;
 900
 901                        /* Update to the new resized array */
 902                        mem_ranges = mrange_info->mem_ranges;
 903                }
 904
 905                start = base;
 906                mem_ranges[mrange_info->mem_range_cnt].base = start;
 907                mrange_info->mem_range_cnt++;
 908        }
 909
 910        mem_ranges[mrange_info->mem_range_cnt - 1].size = (end - start);
 911        pr_debug("%s_memory_range[%d] [%#016llx-%#016llx], %#llx bytes\n",
 912                 mrange_info->name, (mrange_info->mem_range_cnt - 1),
 913                 start, end - 1, (end - start));
 914        return 0;
 915}
 916
 917static int fadump_exclude_reserved_area(u64 start, u64 end)
 918{
 919        u64 ra_start, ra_end;
 920        int ret = 0;
 921
 922        ra_start = fw_dump.reserve_dump_area_start;
 923        ra_end = ra_start + fw_dump.reserve_dump_area_size;
 924
 925        if ((ra_start < end) && (ra_end > start)) {
 926                if ((start < ra_start) && (end > ra_end)) {
 927                        ret = fadump_add_mem_range(&crash_mrange_info,
 928                                                   start, ra_start);
 929                        if (ret)
 930                                return ret;
 931
 932                        ret = fadump_add_mem_range(&crash_mrange_info,
 933                                                   ra_end, end);
 934                } else if (start < ra_start) {
 935                        ret = fadump_add_mem_range(&crash_mrange_info,
 936                                                   start, ra_start);
 937                } else if (ra_end < end) {
 938                        ret = fadump_add_mem_range(&crash_mrange_info,
 939                                                   ra_end, end);
 940                }
 941        } else
 942                ret = fadump_add_mem_range(&crash_mrange_info, start, end);
 943
 944        return ret;
 945}
 946
 947static int fadump_init_elfcore_header(char *bufp)
 948{
 949        struct elfhdr *elf;
 950
 951        elf = (struct elfhdr *) bufp;
 952        bufp += sizeof(struct elfhdr);
 953        memcpy(elf->e_ident, ELFMAG, SELFMAG);
 954        elf->e_ident[EI_CLASS] = ELF_CLASS;
 955        elf->e_ident[EI_DATA] = ELF_DATA;
 956        elf->e_ident[EI_VERSION] = EV_CURRENT;
 957        elf->e_ident[EI_OSABI] = ELF_OSABI;
 958        memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
 959        elf->e_type = ET_CORE;
 960        elf->e_machine = ELF_ARCH;
 961        elf->e_version = EV_CURRENT;
 962        elf->e_entry = 0;
 963        elf->e_phoff = sizeof(struct elfhdr);
 964        elf->e_shoff = 0;
 965#if defined(_CALL_ELF)
 966        elf->e_flags = _CALL_ELF;
 967#else
 968        elf->e_flags = 0;
 969#endif
 970        elf->e_ehsize = sizeof(struct elfhdr);
 971        elf->e_phentsize = sizeof(struct elf_phdr);
 972        elf->e_phnum = 0;
 973        elf->e_shentsize = 0;
 974        elf->e_shnum = 0;
 975        elf->e_shstrndx = 0;
 976
 977        return 0;
 978}
 979
 980/*
 981 * Traverse through memblock structure and setup crash memory ranges. These
 982 * ranges will be used create PT_LOAD program headers in elfcore header.
 983 */
 984static int fadump_setup_crash_memory_ranges(void)
 985{
 986        u64 i, start, end;
 987        int ret;
 988
 989        pr_debug("Setup crash memory ranges.\n");
 990        crash_mrange_info.mem_range_cnt = 0;
 991
 992        /*
 993         * Boot memory region(s) registered with firmware are moved to
 994         * different location at the time of crash. Create separate program
 995         * header(s) for this memory chunk(s) with the correct offset.
 996         */
 997        for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
 998                start = fw_dump.boot_mem_addr[i];
 999                end = start + fw_dump.boot_mem_sz[i];
1000                ret = fadump_add_mem_range(&crash_mrange_info, start, end);
1001                if (ret)
1002                        return ret;
1003        }
1004
1005        for_each_mem_range(i, &start, &end) {
1006                /*
1007                 * skip the memory chunk that is already added
1008                 * (0 through boot_memory_top).
1009                 */
1010                if (start < fw_dump.boot_mem_top) {
1011                        if (end > fw_dump.boot_mem_top)
1012                                start = fw_dump.boot_mem_top;
1013                        else
1014                                continue;
1015                }
1016
1017                /* add this range excluding the reserved dump area. */
1018                ret = fadump_exclude_reserved_area(start, end);
1019                if (ret)
1020                        return ret;
1021        }
1022
1023        return 0;
1024}
1025
1026/*
1027 * If the given physical address falls within the boot memory region then
1028 * return the relocated address that points to the dump region reserved
1029 * for saving initial boot memory contents.
1030 */
1031static inline unsigned long fadump_relocate(unsigned long paddr)
1032{
1033        unsigned long raddr, rstart, rend, rlast, hole_size;
1034        int i;
1035
1036        hole_size = 0;
1037        rlast = 0;
1038        raddr = paddr;
1039        for (i = 0; i < fw_dump.boot_mem_regs_cnt; i++) {
1040                rstart = fw_dump.boot_mem_addr[i];
1041                rend = rstart + fw_dump.boot_mem_sz[i];
1042                hole_size += (rstart - rlast);
1043
1044                if (paddr >= rstart && paddr < rend) {
1045                        raddr += fw_dump.boot_mem_dest_addr - hole_size;
1046                        break;
1047                }
1048
1049                rlast = rend;
1050        }
1051
1052        pr_debug("vmcoreinfo: paddr = 0x%lx, raddr = 0x%lx\n", paddr, raddr);
1053        return raddr;
1054}
1055
1056static int fadump_create_elfcore_headers(char *bufp)
1057{
1058        unsigned long long raddr, offset;
1059        struct elf_phdr *phdr;
1060        struct elfhdr *elf;
1061        int i, j;
1062
1063        fadump_init_elfcore_header(bufp);
1064        elf = (struct elfhdr *)bufp;
1065        bufp += sizeof(struct elfhdr);
1066
1067        /*
1068         * setup ELF PT_NOTE, place holder for cpu notes info. The notes info
1069         * will be populated during second kernel boot after crash. Hence
1070         * this PT_NOTE will always be the first elf note.
1071         *
1072         * NOTE: Any new ELF note addition should be placed after this note.
1073         */
1074        phdr = (struct elf_phdr *)bufp;
1075        bufp += sizeof(struct elf_phdr);
1076        phdr->p_type = PT_NOTE;
1077        phdr->p_flags = 0;
1078        phdr->p_vaddr = 0;
1079        phdr->p_align = 0;
1080
1081        phdr->p_offset = 0;
1082        phdr->p_paddr = 0;
1083        phdr->p_filesz = 0;
1084        phdr->p_memsz = 0;
1085
1086        (elf->e_phnum)++;
1087
1088        /* setup ELF PT_NOTE for vmcoreinfo */
1089        phdr = (struct elf_phdr *)bufp;
1090        bufp += sizeof(struct elf_phdr);
1091        phdr->p_type    = PT_NOTE;
1092        phdr->p_flags   = 0;
1093        phdr->p_vaddr   = 0;
1094        phdr->p_align   = 0;
1095
1096        phdr->p_paddr   = fadump_relocate(paddr_vmcoreinfo_note());
1097        phdr->p_offset  = phdr->p_paddr;
1098        phdr->p_memsz   = phdr->p_filesz = VMCOREINFO_NOTE_SIZE;
1099
1100        /* Increment number of program headers. */
1101        (elf->e_phnum)++;
1102
1103        /* setup PT_LOAD sections. */
1104        j = 0;
1105        offset = 0;
1106        raddr = fw_dump.boot_mem_addr[0];
1107        for (i = 0; i < crash_mrange_info.mem_range_cnt; i++) {
1108                u64 mbase, msize;
1109
1110                mbase = crash_mrange_info.mem_ranges[i].base;
1111                msize = crash_mrange_info.mem_ranges[i].size;
1112                if (!msize)
1113                        continue;
1114
1115                phdr = (struct elf_phdr *)bufp;
1116                bufp += sizeof(struct elf_phdr);
1117                phdr->p_type    = PT_LOAD;
1118                phdr->p_flags   = PF_R|PF_W|PF_X;
1119                phdr->p_offset  = mbase;
1120
1121                if (mbase == raddr) {
1122                        /*
1123                         * The entire real memory region will be moved by
1124                         * firmware to the specified destination_address.
1125                         * Hence set the correct offset.
1126                         */
1127                        phdr->p_offset = fw_dump.boot_mem_dest_addr + offset;
1128                        if (j < (fw_dump.boot_mem_regs_cnt - 1)) {
1129                                offset += fw_dump.boot_mem_sz[j];
1130                                raddr = fw_dump.boot_mem_addr[++j];
1131                        }
1132                }
1133
1134                phdr->p_paddr = mbase;
1135                phdr->p_vaddr = (unsigned long)__va(mbase);
1136                phdr->p_filesz = msize;
1137                phdr->p_memsz = msize;
1138                phdr->p_align = 0;
1139
1140                /* Increment number of program headers. */
1141                (elf->e_phnum)++;
1142        }
1143        return 0;
1144}
1145
1146static unsigned long init_fadump_header(unsigned long addr)
1147{
1148        struct fadump_crash_info_header *fdh;
1149
1150        if (!addr)
1151                return 0;
1152
1153        fdh = __va(addr);
1154        addr += sizeof(struct fadump_crash_info_header);
1155
1156        memset(fdh, 0, sizeof(struct fadump_crash_info_header));
1157        fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
1158        fdh->elfcorehdr_addr = addr;
1159        /* We will set the crashing cpu id in crash_fadump() during crash. */
1160        fdh->crashing_cpu = FADUMP_CPU_UNKNOWN;
1161
1162        return addr;
1163}
1164
1165static int register_fadump(void)
1166{
1167        unsigned long addr;
1168        void *vaddr;
1169        int ret;
1170
1171        /*
1172         * If no memory is reserved then we can not register for firmware-
1173         * assisted dump.
1174         */
1175        if (!fw_dump.reserve_dump_area_size)
1176                return -ENODEV;
1177
1178        ret = fadump_setup_crash_memory_ranges();
1179        if (ret)
1180                return ret;
1181
1182        addr = fw_dump.fadumphdr_addr;
1183
1184        /* Initialize fadump crash info header. */
1185        addr = init_fadump_header(addr);
1186        vaddr = __va(addr);
1187
1188        pr_debug("Creating ELF core headers at %#016lx\n", addr);
1189        fadump_create_elfcore_headers(vaddr);
1190
1191        /* register the future kernel dump with firmware. */
1192        pr_debug("Registering for firmware-assisted kernel dump...\n");
1193        return fw_dump.ops->fadump_register(&fw_dump);
1194}
1195
1196void fadump_cleanup(void)
1197{
1198        if (!fw_dump.fadump_supported)
1199                return;
1200
1201        /* Invalidate the registration only if dump is active. */
1202        if (fw_dump.dump_active) {
1203                pr_debug("Invalidating firmware-assisted dump registration\n");
1204                fw_dump.ops->fadump_invalidate(&fw_dump);
1205        } else if (fw_dump.dump_registered) {
1206                /* Un-register Firmware-assisted dump if it was registered. */
1207                fw_dump.ops->fadump_unregister(&fw_dump);
1208                fadump_free_mem_ranges(&crash_mrange_info);
1209        }
1210
1211        if (fw_dump.ops->fadump_cleanup)
1212                fw_dump.ops->fadump_cleanup(&fw_dump);
1213}
1214
1215static void fadump_free_reserved_memory(unsigned long start_pfn,
1216                                        unsigned long end_pfn)
1217{
1218        unsigned long pfn;
1219        unsigned long time_limit = jiffies + HZ;
1220
1221        pr_info("freeing reserved memory (0x%llx - 0x%llx)\n",
1222                PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
1223
1224        for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1225                free_reserved_page(pfn_to_page(pfn));
1226
1227                if (time_after(jiffies, time_limit)) {
1228                        cond_resched();
1229                        time_limit = jiffies + HZ;
1230                }
1231        }
1232}
1233
1234/*
1235 * Skip memory holes and free memory that was actually reserved.
1236 */
1237static void fadump_release_reserved_area(u64 start, u64 end)
1238{
1239        unsigned long reg_spfn, reg_epfn;
1240        u64 tstart, tend, spfn, epfn;
1241        int i;
1242
1243        spfn = PHYS_PFN(start);
1244        epfn = PHYS_PFN(end);
1245
1246        for_each_mem_pfn_range(i, MAX_NUMNODES, &reg_spfn, &reg_epfn, NULL) {
1247                tstart = max_t(u64, spfn, reg_spfn);
1248                tend   = min_t(u64, epfn, reg_epfn);
1249
1250                if (tstart < tend) {
1251                        fadump_free_reserved_memory(tstart, tend);
1252
1253                        if (tend == epfn)
1254                                break;
1255
1256                        spfn = tend;
1257                }
1258        }
1259}
1260
1261/*
1262 * Sort the mem ranges in-place and merge adjacent ranges
1263 * to minimize the memory ranges count.
1264 */
1265static void sort_and_merge_mem_ranges(struct fadump_mrange_info *mrange_info)
1266{
1267        struct fadump_memory_range *mem_ranges;
1268        struct fadump_memory_range tmp_range;
1269        u64 base, size;
1270        int i, j, idx;
1271
1272        if (!reserved_mrange_info.mem_range_cnt)
1273                return;
1274
1275        /* Sort the memory ranges */
1276        mem_ranges = mrange_info->mem_ranges;
1277        for (i = 0; i < mrange_info->mem_range_cnt; i++) {
1278                idx = i;
1279                for (j = (i + 1); j < mrange_info->mem_range_cnt; j++) {
1280                        if (mem_ranges[idx].base > mem_ranges[j].base)
1281                                idx = j;
1282                }
1283                if (idx != i) {
1284                        tmp_range = mem_ranges[idx];
1285                        mem_ranges[idx] = mem_ranges[i];
1286                        mem_ranges[i] = tmp_range;
1287                }
1288        }
1289
1290        /* Merge adjacent reserved ranges */
1291        idx = 0;
1292        for (i = 1; i < mrange_info->mem_range_cnt; i++) {
1293                base = mem_ranges[i-1].base;
1294                size = mem_ranges[i-1].size;
1295                if (mem_ranges[i].base == (base + size))
1296                        mem_ranges[idx].size += mem_ranges[i].size;
1297                else {
1298                        idx++;
1299                        if (i == idx)
1300                                continue;
1301
1302                        mem_ranges[idx] = mem_ranges[i];
1303                }
1304        }
1305        mrange_info->mem_range_cnt = idx + 1;
1306}
1307
1308/*
1309 * Scan reserved-ranges to consider them while reserving/releasing
1310 * memory for FADump.
1311 */
1312static void __init early_init_dt_scan_reserved_ranges(unsigned long node)
1313{
1314        const __be32 *prop;
1315        int len, ret = -1;
1316        unsigned long i;
1317
1318        /* reserved-ranges already scanned */
1319        if (reserved_mrange_info.mem_range_cnt != 0)
1320                return;
1321
1322        prop = of_get_flat_dt_prop(node, "reserved-ranges", &len);
1323        if (!prop)
1324                return;
1325
1326        /*
1327         * Each reserved range is an (address,size) pair, 2 cells each,
1328         * totalling 4 cells per range.
1329         */
1330        for (i = 0; i < len / (sizeof(*prop) * 4); i++) {
1331                u64 base, size;
1332
1333                base = of_read_number(prop + (i * 4) + 0, 2);
1334                size = of_read_number(prop + (i * 4) + 2, 2);
1335
1336                if (size) {
1337                        ret = fadump_add_mem_range(&reserved_mrange_info,
1338                                                   base, base + size);
1339                        if (ret < 0) {
1340                                pr_warn("some reserved ranges are ignored!\n");
1341                                break;
1342                        }
1343                }
1344        }
1345
1346        /* Compact reserved ranges */
1347        sort_and_merge_mem_ranges(&reserved_mrange_info);
1348}
1349
1350/*
1351 * Release the memory that was reserved during early boot to preserve the
1352 * crash'ed kernel's memory contents except reserved dump area (permanent
1353 * reservation) and reserved ranges used by F/W. The released memory will
1354 * be available for general use.
1355 */
1356static void fadump_release_memory(u64 begin, u64 end)
1357{
1358        u64 ra_start, ra_end, tstart;
1359        int i, ret;
1360
1361        ra_start = fw_dump.reserve_dump_area_start;
1362        ra_end = ra_start + fw_dump.reserve_dump_area_size;
1363
1364        /*
1365         * If reserved ranges array limit is hit, overwrite the last reserved
1366         * memory range with reserved dump area to ensure it is excluded from
1367         * the memory being released (reused for next FADump registration).
1368         */
1369        if (reserved_mrange_info.mem_range_cnt ==
1370            reserved_mrange_info.max_mem_ranges)
1371                reserved_mrange_info.mem_range_cnt--;
1372
1373        ret = fadump_add_mem_range(&reserved_mrange_info, ra_start, ra_end);
1374        if (ret != 0)
1375                return;
1376
1377        /* Get the reserved ranges list in order first. */
1378        sort_and_merge_mem_ranges(&reserved_mrange_info);
1379
1380        /* Exclude reserved ranges and release remaining memory */
1381        tstart = begin;
1382        for (i = 0; i < reserved_mrange_info.mem_range_cnt; i++) {
1383                ra_start = reserved_mrange_info.mem_ranges[i].base;
1384                ra_end = ra_start + reserved_mrange_info.mem_ranges[i].size;
1385
1386                if (tstart >= ra_end)
1387                        continue;
1388
1389                if (tstart < ra_start)
1390                        fadump_release_reserved_area(tstart, ra_start);
1391                tstart = ra_end;
1392        }
1393
1394        if (tstart < end)
1395                fadump_release_reserved_area(tstart, end);
1396}
1397
1398static void fadump_invalidate_release_mem(void)
1399{
1400        mutex_lock(&fadump_mutex);
1401        if (!fw_dump.dump_active) {
1402                mutex_unlock(&fadump_mutex);
1403                return;
1404        }
1405
1406        fadump_cleanup();
1407        mutex_unlock(&fadump_mutex);
1408
1409        fadump_release_memory(fw_dump.boot_mem_top, memblock_end_of_DRAM());
1410        fadump_free_cpu_notes_buf();
1411
1412        /*
1413         * Setup kernel metadata and initialize the kernel dump
1414         * memory structure for FADump re-registration.
1415         */
1416        if (fw_dump.ops->fadump_setup_metadata &&
1417            (fw_dump.ops->fadump_setup_metadata(&fw_dump) < 0))
1418                pr_warn("Failed to setup kernel metadata!\n");
1419        fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1420}
1421
1422static ssize_t release_mem_store(struct kobject *kobj,
1423                                 struct kobj_attribute *attr,
1424                                 const char *buf, size_t count)
1425{
1426        int input = -1;
1427
1428        if (!fw_dump.dump_active)
1429                return -EPERM;
1430
1431        if (kstrtoint(buf, 0, &input))
1432                return -EINVAL;
1433
1434        if (input == 1) {
1435                /*
1436                 * Take away the '/proc/vmcore'. We are releasing the dump
1437                 * memory, hence it will not be valid anymore.
1438                 */
1439#ifdef CONFIG_PROC_VMCORE
1440                vmcore_cleanup();
1441#endif
1442                fadump_invalidate_release_mem();
1443
1444        } else
1445                return -EINVAL;
1446        return count;
1447}
1448
1449/* Release the reserved memory and disable the FADump */
1450static void unregister_fadump(void)
1451{
1452        fadump_cleanup();
1453        fadump_release_memory(fw_dump.reserve_dump_area_start,
1454                              fw_dump.reserve_dump_area_size);
1455        fw_dump.fadump_enabled = 0;
1456        kobject_put(fadump_kobj);
1457}
1458
1459static ssize_t enabled_show(struct kobject *kobj,
1460                            struct kobj_attribute *attr,
1461                            char *buf)
1462{
1463        return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
1464}
1465
1466static ssize_t mem_reserved_show(struct kobject *kobj,
1467                                 struct kobj_attribute *attr,
1468                                 char *buf)
1469{
1470        return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
1471}
1472
1473static ssize_t registered_show(struct kobject *kobj,
1474                               struct kobj_attribute *attr,
1475                               char *buf)
1476{
1477        return sprintf(buf, "%d\n", fw_dump.dump_registered);
1478}
1479
1480static ssize_t registered_store(struct kobject *kobj,
1481                                struct kobj_attribute *attr,
1482                                const char *buf, size_t count)
1483{
1484        int ret = 0;
1485        int input = -1;
1486
1487        if (!fw_dump.fadump_enabled || fw_dump.dump_active)
1488                return -EPERM;
1489
1490        if (kstrtoint(buf, 0, &input))
1491                return -EINVAL;
1492
1493        mutex_lock(&fadump_mutex);
1494
1495        switch (input) {
1496        case 0:
1497                if (fw_dump.dump_registered == 0) {
1498                        goto unlock_out;
1499                }
1500
1501                /* Un-register Firmware-assisted dump */
1502                pr_debug("Un-register firmware-assisted dump\n");
1503                fw_dump.ops->fadump_unregister(&fw_dump);
1504                break;
1505        case 1:
1506                if (fw_dump.dump_registered == 1) {
1507                        /* Un-register Firmware-assisted dump */
1508                        fw_dump.ops->fadump_unregister(&fw_dump);
1509                }
1510                /* Register Firmware-assisted dump */
1511                ret = register_fadump();
1512                break;
1513        default:
1514                ret = -EINVAL;
1515                break;
1516        }
1517
1518unlock_out:
1519        mutex_unlock(&fadump_mutex);
1520        return ret < 0 ? ret : count;
1521}
1522
1523static int fadump_region_show(struct seq_file *m, void *private)
1524{
1525        if (!fw_dump.fadump_enabled)
1526                return 0;
1527
1528        mutex_lock(&fadump_mutex);
1529        fw_dump.ops->fadump_region_show(&fw_dump, m);
1530        mutex_unlock(&fadump_mutex);
1531        return 0;
1532}
1533
1534static struct kobj_attribute release_attr = __ATTR_WO(release_mem);
1535static struct kobj_attribute enable_attr = __ATTR_RO(enabled);
1536static struct kobj_attribute register_attr = __ATTR_RW(registered);
1537static struct kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved);
1538
1539static struct attribute *fadump_attrs[] = {
1540        &enable_attr.attr,
1541        &register_attr.attr,
1542        &mem_reserved_attr.attr,
1543        NULL,
1544};
1545
1546ATTRIBUTE_GROUPS(fadump);
1547
1548DEFINE_SHOW_ATTRIBUTE(fadump_region);
1549
1550static void fadump_init_files(void)
1551{
1552        int rc = 0;
1553
1554        fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
1555        if (!fadump_kobj) {
1556                pr_err("failed to create fadump kobject\n");
1557                return;
1558        }
1559
1560        debugfs_create_file("fadump_region", 0444, powerpc_debugfs_root, NULL,
1561                            &fadump_region_fops);
1562
1563        if (fw_dump.dump_active) {
1564                rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
1565                if (rc)
1566                        pr_err("unable to create release_mem sysfs file (%d)\n",
1567                               rc);
1568        }
1569
1570        rc = sysfs_create_groups(fadump_kobj, fadump_groups);
1571        if (rc) {
1572                pr_err("sysfs group creation failed (%d), unregistering FADump",
1573                       rc);
1574                unregister_fadump();
1575                return;
1576        }
1577
1578        /*
1579         * The FADump sysfs are moved from kernel_kobj to fadump_kobj need to
1580         * create symlink at old location to maintain backward compatibility.
1581         *
1582         *      - fadump_enabled -> fadump/enabled
1583         *      - fadump_registered -> fadump/registered
1584         *      - fadump_release_mem -> fadump/release_mem
1585         */
1586        rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
1587                                                  "enabled", "fadump_enabled");
1588        if (rc) {
1589                pr_err("unable to create fadump_enabled symlink (%d)", rc);
1590                return;
1591        }
1592
1593        rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
1594                                                  "registered",
1595                                                  "fadump_registered");
1596        if (rc) {
1597                pr_err("unable to create fadump_registered symlink (%d)", rc);
1598                sysfs_remove_link(kernel_kobj, "fadump_enabled");
1599                return;
1600        }
1601
1602        if (fw_dump.dump_active) {
1603                rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj,
1604                                                          fadump_kobj,
1605                                                          "release_mem",
1606                                                          "fadump_release_mem");
1607                if (rc)
1608                        pr_err("unable to create fadump_release_mem symlink (%d)",
1609                               rc);
1610        }
1611        return;
1612}
1613
1614/*
1615 * Prepare for firmware-assisted dump.
1616 */
1617int __init setup_fadump(void)
1618{
1619        if (!fw_dump.fadump_supported)
1620                return 0;
1621
1622        fadump_init_files();
1623        fadump_show_config();
1624
1625        if (!fw_dump.fadump_enabled)
1626                return 1;
1627
1628        /*
1629         * If dump data is available then see if it is valid and prepare for
1630         * saving it to the disk.
1631         */
1632        if (fw_dump.dump_active) {
1633                /*
1634                 * if dump process fails then invalidate the registration
1635                 * and release memory before proceeding for re-registration.
1636                 */
1637                if (fw_dump.ops->fadump_process(&fw_dump) < 0)
1638                        fadump_invalidate_release_mem();
1639        }
1640        /* Initialize the kernel dump memory structure for FAD registration. */
1641        else if (fw_dump.reserve_dump_area_size)
1642                fw_dump.ops->fadump_init_mem_struct(&fw_dump);
1643
1644        return 1;
1645}
1646subsys_initcall(setup_fadump);
1647#else /* !CONFIG_PRESERVE_FA_DUMP */
1648
1649/* Scan the Firmware Assisted dump configuration details. */
1650int __init early_init_dt_scan_fw_dump(unsigned long node, const char *uname,
1651                                      int depth, void *data)
1652{
1653        if ((depth != 1) || (strcmp(uname, "ibm,opal") != 0))
1654                return 0;
1655
1656        opal_fadump_dt_scan(&fw_dump, node);
1657        return 1;
1658}
1659
1660/*
1661 * When dump is active but PRESERVE_FA_DUMP is enabled on the kernel,
1662 * preserve crash data. The subsequent memory preserving kernel boot
1663 * is likely to process this crash data.
1664 */
1665int __init fadump_reserve_mem(void)
1666{
1667        if (fw_dump.dump_active) {
1668                /*
1669                 * If last boot has crashed then reserve all the memory
1670                 * above boot memory to preserve crash data.
1671                 */
1672                pr_info("Preserving crash data for processing in next boot.\n");
1673                fadump_reserve_crash_area(fw_dump.boot_mem_top);
1674        } else
1675                pr_debug("FADump-aware kernel..\n");
1676
1677        return 1;
1678}
1679#endif /* CONFIG_PRESERVE_FA_DUMP */
1680
1681/* Preserve everything above the base address */
1682static void __init fadump_reserve_crash_area(u64 base)
1683{
1684        u64 i, mstart, mend, msize;
1685
1686        for_each_mem_range(i, &mstart, &mend) {
1687                msize  = mend - mstart;
1688
1689                if ((mstart + msize) < base)
1690                        continue;
1691
1692                if (mstart < base) {
1693                        msize -= (base - mstart);
1694                        mstart = base;
1695                }
1696
1697                pr_info("Reserving %lluMB of memory at %#016llx for preserving crash data",
1698                        (msize >> 20), mstart);
1699                memblock_reserve(mstart, msize);
1700        }
1701}
1702
1703unsigned long __init arch_reserved_kernel_pages(void)
1704{
1705        return memblock_reserved_size() / PAGE_SIZE;
1706}
1707
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