// 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/kmemleak.h>
#include <linux/cma.h>
#include <linux/crash_reserve.h>

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

#include <crypto/sha1.h>

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

/* 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("crashkernel: 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("crashkernel: 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_CMA  2
#define SUFFIX_NULL 3
static __initdata char *suffix_tbl[] = {
        [SUFFIX_HIGH] = ",high",
        [SUFFIX_LOW]  = ",low",
        [SUFFIX_CMA]  = ",cma",
        [SUFFIX_NULL] = NULL,
};

/*
 * That function parses "suffix"  crashkernel command lines like
 *
 *      crashkernel=size,[high|low|cma]
 *
 * 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,
                             unsigned long long *cma_size,
                             bool *high)
{
        int ret;
        unsigned long long __always_unused cma_base;

        /* 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;
        }

        /*
         * optional CMA reservation
         * cma_base is ignored
         */
        if (cma_size)
                __parse_crashkernel(cmdline, 0, cma_size,
                        &cma_base, suffix_tbl[SUFFIX_CMA]);
#endif
        if (!*crash_size)
                ret = -EINVAL;

        if (*crash_size >= system_ram)
                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;
#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
        insert_resource(&iomem_resource, &crashk_low_res);
#endif
#endif
        return 0;
}

void __init reserve_crashkernel_generic(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;
                        if (search_end != CRASH_ADDR_HIGH_MAX)
                                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;
#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
        insert_resource(&iomem_resource, &crashk_res);
#endif
}

struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX];
#ifdef CRASHKERNEL_CMA
int crashk_cma_cnt;
void __init reserve_crashkernel_cma(unsigned long long cma_size)
{
        unsigned long long request_size = roundup(cma_size, PAGE_SIZE);
        unsigned long long reserved_size = 0;

        if (!cma_size)
                return;

        while (cma_size > reserved_size &&
               crashk_cma_cnt < CRASHKERNEL_CMA_RANGES_MAX) {

                struct cma *res;

                if (cma_declare_contiguous(0, request_size, 0, 0, 0, false,
                                       "crashkernel", &res)) {
                        /* reservation failed, try half-sized blocks */
                        if (request_size <= PAGE_SIZE)
                                break;

                        request_size = roundup(request_size / 2, PAGE_SIZE);
                        continue;
                }

                crashk_cma_ranges[crashk_cma_cnt].start = cma_get_base(res);
                crashk_cma_ranges[crashk_cma_cnt].end =
                        crashk_cma_ranges[crashk_cma_cnt].start +
                        cma_get_size(res) - 1;
                ++crashk_cma_cnt;
                reserved_size += request_size;
        }

        if (cma_size > reserved_size)
                pr_warn("crashkernel CMA reservation failed: %lld MB requested, %lld MB reserved in %d ranges\n",
                        cma_size >> 20, reserved_size >> 20, crashk_cma_cnt);
        else
                pr_info("crashkernel CMA reserved: %lld MB in %d ranges\n",
                        reserved_size >> 20, crashk_cma_cnt);
}

#else /* CRASHKERNEL_CMA */
void __init reserve_crashkernel_cma(unsigned long long cma_size)
{
        if (cma_size)
                pr_warn("crashkernel CMA reservation not supported\n");
}
#endif

#ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
static __init int insert_crashkernel_resources(void)
{
        if (!arch_add_crash_res_to_iomem())
                return 0;

        if (crashk_res.start < crashk_res.end)
                insert_resource(&iomem_resource, &crashk_res);

        if (crashk_low_res.start < crashk_low_res.end)
                insert_resource(&iomem_resource, &crashk_low_res);

        return 0;
}
early_initcall(insert_crashkernel_resources);
#endif
#endif