// SPDX-License-Identifier: GPL-2.0-only
/*
 * crash.c - kernel crash support code.
 * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
 */

#include <linux/buildid.h>
#include <linux/init.h>
#include <linux/utsname.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/kexec.h>
#include <linux/memory.h>
#include <linux/cpuhotplug.h>
#include <linux/memblock.h>
#include <linux/kexec.h>
#include <linux/kmemleak.h>

#include <asm/page.h>
#include <asm/sections.h>

#include <crypto/sha1.h>

#include "kallsyms_internal.h"
#include "kexec_internal.h"

/* Per cpu memory for storing cpu states in case of system crash. */
note_buf_t __percpu *crash_notes;

/* vmcoreinfo stuff */
unsigned char *vmcoreinfo_data;
size_t vmcoreinfo_size;
u32 *vmcoreinfo_note;

/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
static unsigned char *vmcoreinfo_data_safecopy;

/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
        .name  = "Crash kernel",
        .start = 0,
        .end   = 0,
        .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
        .desc  = IORES_DESC_CRASH_KERNEL
};
struct resource crashk_low_res = {
        .name  = "Crash kernel",
        .start = 0,
        .end   = 0,
        .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
        .desc  = IORES_DESC_CRASH_KERNEL
};

/*
 * parsing the "crashkernel" commandline
 *
 * this code is intended to be called from architecture specific code
 */


/*
 * This function parses command lines in the format
 *
 *   crashkernel=ramsize-range:size[,...][@offset]
 *
 * The function returns 0 on success and -EINVAL on failure.
 */
static int __init parse_crashkernel_mem(char *cmdline,
                                        unsigned long long system_ram,
                                        unsigned long long *crash_size,
                                        unsigned long long *crash_base)
{
        char *cur = cmdline, *tmp;
        unsigned long long total_mem = system_ram;

        /*
         * Firmware sometimes reserves some memory regions for its own use,
         * so the system memory size is less than the actual physical memory
         * size. Work around this by rounding up the total size to 128M,
         * which is enough for most test cases.
         */
        total_mem = roundup(total_mem, SZ_128M);

        /* for each entry of the comma-separated list */
        do {
                unsigned long long start, end = ULLONG_MAX, size;

                /* get the start of the range */
                start = memparse(cur, &tmp);
                if (cur == tmp) {
                        pr_warn("crashkernel: Memory value expected\n");
                        return -EINVAL;
                }
                cur = tmp;
                if (*cur != '-') {
                        pr_warn("crashkernel: '-' expected\n");
                        return -EINVAL;
                }
                cur++;

                /* if no ':' is here, than we read the end */
                if (*cur != ':') {
                        end = memparse(cur, &tmp);
                        if (cur == tmp) {
                                pr_warn("crashkernel: Memory value expected\n");
                                return -EINVAL;
                        }
                        cur = tmp;
                        if (end <= start) {
                                pr_warn("crashkernel: end <= start\n");
                                return -EINVAL;
                        }
                }

                if (*cur != ':') {
                        pr_warn("crashkernel: ':' expected\n");
                        return -EINVAL;
                }
                cur++;

                size = memparse(cur, &tmp);
                if (cur == tmp) {
                        pr_warn("Memory value expected\n");
                        return -EINVAL;
                }
                cur = tmp;
                if (size >= total_mem) {
                        pr_warn("crashkernel: invalid size\n");
                        return -EINVAL;
                }

                /* match ? */
                if (total_mem >= start && total_mem < end) {
                        *crash_size = size;
                        break;
                }
        } while (*cur++ == ',');

        if (*crash_size > 0) {
                while (*cur && *cur != ' ' && *cur != '@')
                        cur++;
                if (*cur == '@') {
                        cur++;
                        *crash_base = memparse(cur, &tmp);
                        if (cur == tmp) {
                                pr_warn("Memory value expected after '@'\n");
                                return -EINVAL;
                        }
                }
        } else
                pr_info("crashkernel size resulted in zero bytes\n");

        return 0;
}

/*
 * That function parses "simple" (old) crashkernel command lines like
 *
 *      crashkernel=size[@offset]
 *
 * It returns 0 on success and -EINVAL on failure.
 */
static int __init parse_crashkernel_simple(char *cmdline,
                                           unsigned long long *crash_size,
                                           unsigned long long *crash_base)
{
        char *cur = cmdline;

        *crash_size = memparse(cmdline, &cur);
        if (cmdline == cur) {
                pr_warn("crashkernel: memory value expected\n");
                return -EINVAL;
        }

        if (*cur == '@')
                *crash_base = memparse(cur+1, &cur);
        else if (*cur != ' ' && *cur != '\0') {
                pr_warn("crashkernel: unrecognized char: %c\n", *cur);
                return -EINVAL;
        }

        return 0;
}

#define SUFFIX_HIGH 0
#define SUFFIX_LOW  1
#define SUFFIX_NULL 2
static __initdata char *suffix_tbl[] = {
        [SUFFIX_HIGH] = ",high",
        [SUFFIX_LOW]  = ",low",
        [SUFFIX_NULL] = NULL,
};

/*
 * That function parses "suffix"  crashkernel command lines like
 *
 *      crashkernel=size,[high|low]
 *
 * It returns 0 on success and -EINVAL on failure.
 */
static int __init parse_crashkernel_suffix(char *cmdline,
                                           unsigned long long *crash_size,
                                           const char *suffix)
{
        char *cur = cmdline;

        *crash_size = memparse(cmdline, &cur);
        if (cmdline == cur) {
                pr_warn("crashkernel: memory value expected\n");
                return -EINVAL;
        }

        /* check with suffix */
        if (strncmp(cur, suffix, strlen(suffix))) {
                pr_warn("crashkernel: unrecognized char: %c\n", *cur);
                return -EINVAL;
        }
        cur += strlen(suffix);
        if (*cur != ' ' && *cur != '\0') {
                pr_warn("crashkernel: unrecognized char: %c\n", *cur);
                return -EINVAL;
        }

        return 0;
}

static __init char *get_last_crashkernel(char *cmdline,
                             const char *name,
                             const char *suffix)
{
        char *p = cmdline, *ck_cmdline = NULL;

        /* find crashkernel and use the last one if there are more */
        p = strstr(p, name);
        while (p) {
                char *end_p = strchr(p, ' ');
                char *q;

                if (!end_p)
                        end_p = p + strlen(p);

                if (!suffix) {
                        int i;

                        /* skip the one with any known suffix */
                        for (i = 0; suffix_tbl[i]; i++) {
                                q = end_p - strlen(suffix_tbl[i]);
                                if (!strncmp(q, suffix_tbl[i],
                                             strlen(suffix_tbl[i])))
                                        goto next;
                        }
                        ck_cmdline = p;
                } else {
                        q = end_p - strlen(suffix);
                        if (!strncmp(q, suffix, strlen(suffix)))
                                ck_cmdline = p;
                }
next:
                p = strstr(p+1, name);
        }

        return ck_cmdline;
}

static int __init __parse_crashkernel(char *cmdline,
                             unsigned long long system_ram,
                             unsigned long long *crash_size,
                             unsigned long long *crash_base,
                             const char *suffix)
{
        char *first_colon, *first_space;
        char *ck_cmdline;
        char *name = "crashkernel=";

        BUG_ON(!crash_size || !crash_base);
        *crash_size = 0;
        *crash_base = 0;

        ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
        if (!ck_cmdline)
                return -ENOENT;

        ck_cmdline += strlen(name);

        if (suffix)
                return parse_crashkernel_suffix(ck_cmdline, crash_size,
                                suffix);
        /*
         * if the commandline contains a ':', then that's the extended
         * syntax -- if not, it must be the classic syntax
         */
        first_colon = strchr(ck_cmdline, ':');
        first_space = strchr(ck_cmdline, ' ');
        if (first_colon && (!first_space || first_colon < first_space))
                return parse_crashkernel_mem(ck_cmdline, system_ram,
                                crash_size, crash_base);

        return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
}

/*
 * That function is the entry point for command line parsing and should be
 * called from the arch-specific code.
 *
 * If crashkernel=,high|low is supported on architecture, non-NULL values
 * should be passed to parameters 'low_size' and 'high'.
 */
int __init parse_crashkernel(char *cmdline,
                             unsigned long long system_ram,
                             unsigned long long *crash_size,
                             unsigned long long *crash_base,
                             unsigned long long *low_size,
                             bool *high)
{
        int ret;

        /* crashkernel=X[@offset] */
        ret = __parse_crashkernel(cmdline, system_ram, crash_size,
                                crash_base, NULL);
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
        /*
         * If non-NULL 'high' passed in and no normal crashkernel
         * setting detected, try parsing crashkernel=,high|low.
         */
        if (high && ret == -ENOENT) {
                ret = __parse_crashkernel(cmdline, 0, crash_size,
                                crash_base, suffix_tbl[SUFFIX_HIGH]);
                if (ret || !*crash_size)
                        return -EINVAL;

                /*
                 * crashkernel=Y,low can be specified or not, but invalid value
                 * is not allowed.
                 */
                ret = __parse_crashkernel(cmdline, 0, low_size,
                                crash_base, suffix_tbl[SUFFIX_LOW]);
                if (ret == -ENOENT) {
                        *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
                        ret = 0;
                } else if (ret) {
                        return ret;
                }

                *high = true;
        }
#endif
        if (!*crash_size)
                ret = -EINVAL;

        return ret;
}

/*
 * Add a dummy early_param handler to mark crashkernel= as a known command line
 * parameter and suppress incorrect warnings in init/main.c.
 */
static int __init parse_crashkernel_dummy(char *arg)
{
        return 0;
}
early_param("crashkernel", parse_crashkernel_dummy);

#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
static int __init reserve_crashkernel_low(unsigned long long low_size)
{
#ifdef CONFIG_64BIT
        unsigned long long low_base;

        low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
        if (!low_base) {
                pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
                return -ENOMEM;
        }

        pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
                low_base, low_base + low_size, low_size >> 20);

        crashk_low_res.start = low_base;
        crashk_low_res.end   = low_base + low_size - 1;
        insert_resource(&iomem_resource, &crashk_low_res);
#endif
        return 0;
}

void __init reserve_crashkernel_generic(char *cmdline,
                             unsigned long long crash_size,
                             unsigned long long crash_base,
                             unsigned long long crash_low_size,
                             bool high)
{
        unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
        bool fixed_base = false;

        /* User specifies base address explicitly. */
        if (crash_base) {
                fixed_base = true;
                search_base = crash_base;
                search_end = crash_base + crash_size;
        } else if (high) {
                search_base = CRASH_ADDR_LOW_MAX;
                search_end = CRASH_ADDR_HIGH_MAX;
        }

retry:
        crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
                                               search_base, search_end);
        if (!crash_base) {
                /*
                 * For crashkernel=size[KMG]@offset[KMG], print out failure
                 * message if can't reserve the specified region.
                 */
                if (fixed_base) {
                        pr_warn("crashkernel reservation failed - memory is in use.\n");
                        return;
                }

                /*
                 * For crashkernel=size[KMG], if the first attempt was for
                 * low memory, fall back to high memory, the minimum required
                 * low memory will be reserved later.
                 */
                if (!high && search_end == CRASH_ADDR_LOW_MAX) {
                        search_end = CRASH_ADDR_HIGH_MAX;
                        search_base = CRASH_ADDR_LOW_MAX;
                        crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
                        goto retry;
                }

                /*
                 * For crashkernel=size[KMG],high, if the first attempt was
                 * for high memory, fall back to low memory.
                 */
                if (high && search_end == CRASH_ADDR_HIGH_MAX) {
                        search_end = CRASH_ADDR_LOW_MAX;
                        search_base = 0;
                        goto retry;
                }
                pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
                        crash_size);
                return;
        }

        if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
             crash_low_size && reserve_crashkernel_low(crash_low_size)) {
                memblock_phys_free(crash_base, crash_size);
                return;
        }

        pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
                crash_base, crash_base + crash_size, crash_size >> 20);

        /*
         * The crashkernel memory will be removed from the kernel linear
         * map. Inform kmemleak so that it won't try to access it.
         */
        kmemleak_ignore_phys(crash_base);
        if (crashk_low_res.end)
                kmemleak_ignore_phys(crashk_low_res.start);

        crashk_res.start = crash_base;
        crashk_res.end = crash_base + crash_size - 1;
        insert_resource(&iomem_resource, &crashk_res);
}
#endif

int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
                          void **addr, unsigned long *sz)
{
        Elf64_Ehdr *ehdr;
        Elf64_Phdr *phdr;
        unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
        unsigned char *buf;
        unsigned int cpu, i;
        unsigned long long notes_addr;
        unsigned long mstart, mend;

        /* extra phdr for vmcoreinfo ELF note */
        nr_phdr = nr_cpus + 1;
        nr_phdr += mem->nr_ranges;

        /*
         * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
         * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
         * I think this is required by tools like gdb. So same physical
         * memory will be mapped in two ELF headers. One will contain kernel
         * text virtual addresses and other will have __va(physical) addresses.
         */

        nr_phdr++;
        elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
        elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);

        buf = vzalloc(elf_sz);
        if (!buf)
                return -ENOMEM;

        ehdr = (Elf64_Ehdr *)buf;
        phdr = (Elf64_Phdr *)(ehdr + 1);
        memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
        ehdr->e_ident[EI_CLASS] = ELFCLASS64;
        ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
        ehdr->e_ident[EI_VERSION] = EV_CURRENT;
        ehdr->e_ident[EI_OSABI] = ELF_OSABI;
        memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
        ehdr->e_type = ET_CORE;
        ehdr->e_machine = ELF_ARCH;
        ehdr->e_version = EV_CURRENT;
        ehdr->e_phoff = sizeof(Elf64_Ehdr);
        ehdr->e_ehsize = sizeof(Elf64_Ehdr);
        ehdr->e_phentsize = sizeof(Elf64_Phdr);

        /* Prepare one phdr of type PT_NOTE for each possible CPU */
        for_each_possible_cpu(cpu) {
                phdr->p_type = PT_NOTE;
                notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
                phdr->p_offset = phdr->p_paddr = notes_addr;
                phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
                (ehdr->e_phnum)++;
                phdr++;
        }

        /* Prepare one PT_NOTE header for vmcoreinfo */
        phdr->p_type = PT_NOTE;
        phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
        phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
        (ehdr->e_phnum)++;
        phdr++;

        /* Prepare PT_LOAD type program header for kernel text region */
        if (need_kernel_map) {
                phdr->p_type = PT_LOAD;
                phdr->p_flags = PF_R|PF_W|PF_X;
                phdr->p_vaddr = (unsigned long) _text;
                phdr->p_filesz = phdr->p_memsz = _end - _text;
                phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
                ehdr->e_phnum++;
                phdr++;
        }

        /* Go through all the ranges in mem->ranges[] and prepare phdr */
        for (i = 0; i < mem->nr_ranges; i++) {
                mstart = mem->ranges[i].start;
                mend = mem->ranges[i].end;

                phdr->p_type = PT_LOAD;
                phdr->p_flags = PF_R|PF_W|PF_X;
                phdr->p_offset  = mstart;

                phdr->p_paddr = mstart;
                phdr->p_vaddr = (unsigned long) __va(mstart);
                phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
                phdr->p_align = 0;
                ehdr->e_phnum++;
                pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
                        phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
                        ehdr->e_phnum, phdr->p_offset);
                phdr++;
        }

        *addr = buf;
        *sz = elf_sz;
        return 0;
}

int crash_exclude_mem_range(struct crash_mem *mem,
                            unsigned long long mstart, unsigned long long mend)
{
        int i, j;
        unsigned long long start, end, p_start, p_end;
        struct range temp_range = {0, 0};

        for (i = 0; i < mem->nr_ranges; i++) {
                start = mem->ranges[i].start;
                end = mem->ranges[i].end;
                p_start = mstart;
                p_end = mend;

                if (mstart > end || mend < start)
                        continue;

                /* Truncate any area outside of range */
                if (mstart < start)
                        p_start = start;
                if (mend > end)
                        p_end = end;

                /* Found completely overlapping range */
                if (p_start == start && p_end == end) {
                        mem->ranges[i].start = 0;
                        mem->ranges[i].end = 0;
                        if (i < mem->nr_ranges - 1) {
                                /* Shift rest of the ranges to left */
                                for (j = i; j < mem->nr_ranges - 1; j++) {
                                        mem->ranges[j].start =
                                                mem->ranges[j+1].start;
                                        mem->ranges[j].end =
                                                        mem->ranges[j+1].end;
                                }

                                /*
                                 * Continue to check if there are another overlapping ranges
                                 * from the current position because of shifting the above
                                 * mem ranges.
                                 */
                                i--;
                                mem->nr_ranges--;
                                continue;
                        }
                        mem->nr_ranges--;
                        return 0;
                }

                if (p_start > start && p_end < end) {
                        /* Split original range */
                        mem->ranges[i].end = p_start - 1;
                        temp_range.start = p_end + 1;
                        temp_range.end = end;
                } else if (p_start != start)
                        mem->ranges[i].end = p_start - 1;
                else
                        mem->ranges[i].start = p_end + 1;
                break;
        }

        /* If a split happened, add the split to array */
        if (!temp_range.end)
                return 0;

        /* Split happened */
        if (i == mem->max_nr_ranges - 1)
                return -ENOMEM;

        /* Location where new range should go */
        j = i + 1;
        if (j < mem->nr_ranges) {
                /* Move over all ranges one slot towards the end */
                for (i = mem->nr_ranges - 1; i >= j; i--)
                        mem->ranges[i + 1] = mem->ranges[i];
        }

        mem->ranges[j].start = temp_range.start;
        mem->ranges[j].end = temp_range.end;
        mem->nr_ranges++;
        return 0;
}

Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
                          void *data, size_t data_len)
{
        struct elf_note *note = (struct elf_note *)buf;

        note->n_namesz = strlen(name) + 1;
        note->n_descsz = data_len;
        note->n_type   = type;
        buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
        memcpy(buf, name, note->n_namesz);
        buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
        memcpy(buf, data, data_len);
        buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));

        return buf;
}

void final_note(Elf_Word *buf)
{
        memset(buf, 0, sizeof(struct elf_note));
}

static void update_vmcoreinfo_note(void)
{
        u32 *buf = vmcoreinfo_note;

        if (!vmcoreinfo_size)
                return;
        buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
                              vmcoreinfo_size);
        final_note(buf);
}

void crash_update_vmcoreinfo_safecopy(void *ptr)
{
        if (ptr)
                memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);

        vmcoreinfo_data_safecopy = ptr;
}

void crash_save_vmcoreinfo(void)
{
        if (!vmcoreinfo_note)
                return;

        /* Use the safe copy to generate vmcoreinfo note if have */
        if (vmcoreinfo_data_safecopy)
                vmcoreinfo_data = vmcoreinfo_data_safecopy;

        vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
        update_vmcoreinfo_note();
}

void vmcoreinfo_append_str(const char *fmt, ...)
{
        va_list args;
        char buf[0x50];
        size_t r;

        va_start(args, fmt);
        r = vscnprintf(buf, sizeof(buf), fmt, args);
        va_end(args);

        r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);

        memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);

        vmcoreinfo_size += r;

        WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
                  "vmcoreinfo data exceeds allocated size, truncating");
}

/*
 * provide an empty default implementation here -- architecture
 * code may override this
 */
void __weak arch_crash_save_vmcoreinfo(void)
{}

phys_addr_t __weak paddr_vmcoreinfo_note(void)
{
        return __pa(vmcoreinfo_note);
}
EXPORT_SYMBOL(paddr_vmcoreinfo_note);

static int __init crash_save_vmcoreinfo_init(void)
{
        vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
        if (!vmcoreinfo_data) {
                pr_warn("Memory allocation for vmcoreinfo_data failed\n");
                return -ENOMEM;
        }

        vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
                                                GFP_KERNEL | __GFP_ZERO);
        if (!vmcoreinfo_note) {
                free_page((unsigned long)vmcoreinfo_data);
                vmcoreinfo_data = NULL;
                pr_warn("Memory allocation for vmcoreinfo_note failed\n");
                return -ENOMEM;
        }

        VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
        VMCOREINFO_BUILD_ID();
        VMCOREINFO_PAGESIZE(PAGE_SIZE);

        VMCOREINFO_SYMBOL(init_uts_ns);
        VMCOREINFO_OFFSET(uts_namespace, name);
        VMCOREINFO_SYMBOL(node_online_map);
#ifdef CONFIG_MMU
        VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
#endif
        VMCOREINFO_SYMBOL(_stext);
        VMCOREINFO_SYMBOL(vmap_area_list);

#ifndef CONFIG_NUMA
        VMCOREINFO_SYMBOL(mem_map);
        VMCOREINFO_SYMBOL(contig_page_data);
#endif
#ifdef CONFIG_SPARSEMEM
        VMCOREINFO_SYMBOL_ARRAY(mem_section);
        VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
        VMCOREINFO_STRUCT_SIZE(mem_section);
        VMCOREINFO_OFFSET(mem_section, section_mem_map);
        VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
        VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
#endif
        VMCOREINFO_STRUCT_SIZE(page);
        VMCOREINFO_STRUCT_SIZE(pglist_data);
        VMCOREINFO_STRUCT_SIZE(zone);
        VMCOREINFO_STRUCT_SIZE(free_area);
        VMCOREINFO_STRUCT_SIZE(list_head);
        VMCOREINFO_SIZE(nodemask_t);
        VMCOREINFO_OFFSET(page, flags);
        VMCOREINFO_OFFSET(page, _refcount);
        VMCOREINFO_OFFSET(page, mapping);
        VMCOREINFO_OFFSET(page, lru);
        VMCOREINFO_OFFSET(page, _mapcount);
        VMCOREINFO_OFFSET(page, private);
        VMCOREINFO_OFFSET(page, compound_head);
        VMCOREINFO_OFFSET(pglist_data, node_zones);
        VMCOREINFO_OFFSET(pglist_data, nr_zones);
#ifdef CONFIG_FLATMEM
        VMCOREINFO_OFFSET(pglist_data, node_mem_map);
#endif
        VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
        VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
        VMCOREINFO_OFFSET(pglist_data, node_id);
        VMCOREINFO_OFFSET(zone, free_area);
        VMCOREINFO_OFFSET(zone, vm_stat);
        VMCOREINFO_OFFSET(zone, spanned_pages);
        VMCOREINFO_OFFSET(free_area, free_list);
        VMCOREINFO_OFFSET(list_head, next);
        VMCOREINFO_OFFSET(list_head, prev);
        VMCOREINFO_OFFSET(vmap_area, va_start);
        VMCOREINFO_OFFSET(vmap_area, list);
        VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1);
        log_buf_vmcoreinfo_setup();
        VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
        VMCOREINFO_NUMBER(NR_FREE_PAGES);
        VMCOREINFO_NUMBER(PG_lru);
        VMCOREINFO_NUMBER(PG_private);
        VMCOREINFO_NUMBER(PG_swapcache);
        VMCOREINFO_NUMBER(PG_swapbacked);
        VMCOREINFO_NUMBER(PG_slab);
#ifdef CONFIG_MEMORY_FAILURE
        VMCOREINFO_NUMBER(PG_hwpoison);
#endif
        VMCOREINFO_NUMBER(PG_head_mask);
#define PAGE_BUDDY_MAPCOUNT_VALUE       (~PG_buddy)
        VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
#ifdef CONFIG_HUGETLB_PAGE
        VMCOREINFO_NUMBER(PG_hugetlb);
#define PAGE_OFFLINE_MAPCOUNT_VALUE     (~PG_offline)
        VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
#endif

#ifdef CONFIG_KALLSYMS
        VMCOREINFO_SYMBOL(kallsyms_names);
        VMCOREINFO_SYMBOL(kallsyms_num_syms);
        VMCOREINFO_SYMBOL(kallsyms_token_table);
        VMCOREINFO_SYMBOL(kallsyms_token_index);
#ifdef CONFIG_KALLSYMS_BASE_RELATIVE
        VMCOREINFO_SYMBOL(kallsyms_offsets);
        VMCOREINFO_SYMBOL(kallsyms_relative_base);
#else
        VMCOREINFO_SYMBOL(kallsyms_addresses);
#endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
#endif /* CONFIG_KALLSYMS */

        arch_crash_save_vmcoreinfo();
        update_vmcoreinfo_note();

        return 0;
}

subsys_initcall(crash_save_vmcoreinfo_init);

static int __init crash_notes_memory_init(void)
{
        /* Allocate memory for saving cpu registers. */
        size_t size, align;

        /*
         * crash_notes could be allocated across 2 vmalloc pages when percpu
         * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
         * pages are also on 2 continuous physical pages. In this case the
         * 2nd part of crash_notes in 2nd page could be lost since only the
         * starting address and size of crash_notes are exported through sysfs.
         * Here round up the size of crash_notes to the nearest power of two
         * and pass it to __alloc_percpu as align value. This can make sure
         * crash_notes is allocated inside one physical page.
         */
        size = sizeof(note_buf_t);
        align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);

        /*
         * Break compile if size is bigger than PAGE_SIZE since crash_notes
         * definitely will be in 2 pages with that.
         */
        BUILD_BUG_ON(size > PAGE_SIZE);

        crash_notes = __alloc_percpu(size, align);
        if (!crash_notes) {
                pr_warn("Memory allocation for saving cpu register states failed\n");
                return -ENOMEM;
        }
        return 0;
}
subsys_initcall(crash_notes_memory_init);

#ifdef CONFIG_CRASH_HOTPLUG
#undef pr_fmt
#define pr_fmt(fmt) "crash hp: " fmt

/*
 * Different than kexec/kdump loading/unloading/jumping/shrinking which
 * usually rarely happen, there will be many crash hotplug events notified
 * during one short period, e.g one memory board is hot added and memory
 * regions are online. So mutex lock  __crash_hotplug_lock is used to
 * serialize the crash hotplug handling specifically.
 */
DEFINE_MUTEX(__crash_hotplug_lock);
#define crash_hotplug_lock() mutex_lock(&__crash_hotplug_lock)
#define crash_hotplug_unlock() mutex_unlock(&__crash_hotplug_lock)

/*
 * This routine utilized when the crash_hotplug sysfs node is read.
 * It reflects the kernel's ability/permission to update the crash
 * elfcorehdr directly.
 */
int crash_check_update_elfcorehdr(void)
{
        int rc = 0;

        crash_hotplug_lock();
        /* Obtain lock while reading crash information */
        if (!kexec_trylock()) {
                pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
                crash_hotplug_unlock();
                return 0;
        }
        if (kexec_crash_image) {
                if (kexec_crash_image->file_mode)
                        rc = 1;
                else
                        rc = kexec_crash_image->update_elfcorehdr;
        }
        /* Release lock now that update complete */
        kexec_unlock();
        crash_hotplug_unlock();

        return rc;
}

/*
 * To accurately reflect hot un/plug changes of cpu and memory resources
 * (including onling and offlining of those resources), the elfcorehdr
 * (which is passed to the crash kernel via the elfcorehdr= parameter)
 * must be updated with the new list of CPUs and memories.
 *
 * In order to make changes to elfcorehdr, two conditions are needed:
 * First, the segment containing the elfcorehdr must be large enough
 * to permit a growing number of resources; the elfcorehdr memory size
 * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES.
 * Second, purgatory must explicitly exclude the elfcorehdr from the
 * list of segments it checks (since the elfcorehdr changes and thus
 * would require an update to purgatory itself to update the digest).
 */
static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
{
        struct kimage *image;

        crash_hotplug_lock();
        /* Obtain lock while changing crash information */
        if (!kexec_trylock()) {
                pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
                crash_hotplug_unlock();
                return;
        }

        /* Check kdump is not loaded */
        if (!kexec_crash_image)
                goto out;

        image = kexec_crash_image;

        /* Check that updating elfcorehdr is permitted */
        if (!(image->file_mode || image->update_elfcorehdr))
                goto out;

        if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
                hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
                pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
        else
                pr_debug("hp_action %u\n", hp_action);

        /*
         * The elfcorehdr_index is set to -1 when the struct kimage
         * is allocated. Find the segment containing the elfcorehdr,
         * if not already found.
         */
        if (image->elfcorehdr_index < 0) {
                unsigned long mem;
                unsigned char *ptr;
                unsigned int n;

                for (n = 0; n < image->nr_segments; n++) {
                        mem = image->segment[n].mem;
                        ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
                        if (ptr) {
                                /* The segment containing elfcorehdr */
                                if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
                                        image->elfcorehdr_index = (int)n;
                                kunmap_local(ptr);
                        }
                }
        }

        if (image->elfcorehdr_index < 0) {
                pr_err("unable to locate elfcorehdr segment");
                goto out;
        }

        /* Needed in order for the segments to be updated */
        arch_kexec_unprotect_crashkres();

        /* Differentiate between normal load and hotplug update */
        image->hp_action = hp_action;

        /* Now invoke arch-specific update handler */
        arch_crash_handle_hotplug_event(image);

        /* No longer handling a hotplug event */
        image->hp_action = KEXEC_CRASH_HP_NONE;
        image->elfcorehdr_updated = true;

        /* Change back to read-only */
        arch_kexec_protect_crashkres();

        /* Errors in the callback is not a reason to rollback state */
out:
        /* Release lock now that update complete */
        kexec_unlock();
        crash_hotplug_unlock();
}

static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
{
        switch (val) {
        case MEM_ONLINE:
                crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
                        KEXEC_CRASH_HP_INVALID_CPU);
                break;

        case MEM_OFFLINE:
                crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
                        KEXEC_CRASH_HP_INVALID_CPU);
                break;
        }
        return NOTIFY_OK;
}

static struct notifier_block crash_memhp_nb = {
        .notifier_call = crash_memhp_notifier,
        .priority = 0
};

static int crash_cpuhp_online(unsigned int cpu)
{
        crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
        return 0;
}

static int crash_cpuhp_offline(unsigned int cpu)
{
        crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
        return 0;
}

static int __init crash_hotplug_init(void)
{
        int result = 0;

        if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
                register_memory_notifier(&crash_memhp_nb);

        if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
                result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
                        "crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
        }

        return result;
}

subsys_initcall(crash_hotplug_init);
#endif