// SPDX-License-Identifier: GPL-2.0
/*
 * kexec_file for LoongArch
 *
 * Author: Youling Tang <tangyouling@kylinos.cn>
 * Copyright (C) 2025 KylinSoft Corporation.
 *
 * Most code is derived from LoongArch port of kexec-tools
 */

#define pr_fmt(fmt) "kexec_file: " fmt

#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <asm/bootinfo.h>

const struct kexec_file_ops * const kexec_file_loaders[] = {
        &kexec_efi_ops,
        &kexec_elf_ops,
        NULL
};

int arch_kimage_file_post_load_cleanup(struct kimage *image)
{
        vfree(image->elf_headers);
        image->elf_headers = NULL;
        image->elf_headers_sz = 0;

        return kexec_image_post_load_cleanup_default(image);
}

/* Add the "kexec_file" command line parameter to command line. */
static void cmdline_add_loader(unsigned long *cmdline_tmplen, char *modified_cmdline)
{
        int loader_strlen;

        loader_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "kexec_file ");
        *cmdline_tmplen += loader_strlen;
}

/* Add the "initrd=start,size" command line parameter to command line. */
static void cmdline_add_initrd(struct kimage *image, unsigned long *cmdline_tmplen,
                                char *modified_cmdline, unsigned long initrd)
{
        int initrd_strlen;

        initrd_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "initrd=0x%lx,0x%lx ",
                initrd, image->initrd_buf_len);
        *cmdline_tmplen += initrd_strlen;
}

#ifdef CONFIG_CRASH_DUMP

static int prepare_elf_headers(void **addr, unsigned long *sz)
{
        int ret, nr_ranges;
        uint64_t i;
        phys_addr_t start, end;
        struct crash_mem *cmem;

        nr_ranges = 2; /* for exclusion of crashkernel region */
        for_each_mem_range(i, &start, &end)
                nr_ranges++;

        cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
        if (!cmem)
                return -ENOMEM;

        cmem->max_nr_ranges = nr_ranges;
        cmem->nr_ranges = 0;
        for_each_mem_range(i, &start, &end) {
                cmem->ranges[cmem->nr_ranges].start = start;
                cmem->ranges[cmem->nr_ranges].end = end - 1;
                cmem->nr_ranges++;
        }

        /* Exclude crashkernel region */
        ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
        if (ret < 0)
                goto out;

        if (crashk_low_res.end) {
                ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
                if (ret < 0)
                        goto out;
        }

        ret = crash_prepare_elf64_headers(cmem, true, addr, sz);

out:
        kfree(cmem);
        return ret;
}

/*
 * Add the "mem=size@start" command line parameter to command line, indicating the
 * memory region the new kernel can use to boot into.
 */
static void cmdline_add_mem(unsigned long *cmdline_tmplen, char *modified_cmdline)
{
        int mem_strlen = 0;

        mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
                crashk_res.end - crashk_res.start + 1, crashk_res.start);
        *cmdline_tmplen += mem_strlen;

        if (crashk_low_res.end) {
                mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
                        crashk_low_res.end - crashk_low_res.start + 1, crashk_low_res.start);
                *cmdline_tmplen += mem_strlen;
        }
}

/* Add the "elfcorehdr=size@start" command line parameter to command line. */
static void cmdline_add_elfcorehdr(struct kimage *image, unsigned long *cmdline_tmplen,
                                   char *modified_cmdline, unsigned long elfcorehdr_sz)
{
        int elfcorehdr_strlen = 0;

        elfcorehdr_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "elfcorehdr=0x%lx@0x%lx ",
                elfcorehdr_sz, image->elf_load_addr);
        *cmdline_tmplen += elfcorehdr_strlen;
}

#endif

/*
 * Try to add the initrd to the image. If it is not possible to find valid
 * locations, this function will undo changes to the image and return non zero.
 */
int load_other_segments(struct kimage *image,
                        unsigned long kernel_load_addr, unsigned long kernel_size,
                        char *initrd, unsigned long initrd_len, char *cmdline, unsigned long cmdline_len)
{
        int ret = 0;
        unsigned long cmdline_tmplen = 0;
        unsigned long initrd_load_addr = 0;
        unsigned long orig_segments = image->nr_segments;
        char *modified_cmdline = NULL;
        struct kexec_buf kbuf = {};

        kbuf.image = image;
        /* Don't allocate anything below the kernel */
        kbuf.buf_min = kernel_load_addr + kernel_size;

        modified_cmdline = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
        if (!modified_cmdline)
                return -EINVAL;

        cmdline_add_loader(&cmdline_tmplen, modified_cmdline);
        /* Ensure it's null terminated */
        modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';

#ifdef CONFIG_CRASH_DUMP
        /* Load elf core header */
        if (image->type == KEXEC_TYPE_CRASH) {
                void *headers;
                unsigned long headers_sz;

                ret = prepare_elf_headers(&headers, &headers_sz);
                if (ret < 0) {
                        pr_err("Preparing elf core header failed\n");
                        goto out_err;
                }

                kbuf.buffer = headers;
                kbuf.bufsz = headers_sz;
                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                kbuf.memsz = headers_sz;
                kbuf.buf_align = SZ_64K; /* largest supported page size */
                kbuf.buf_max = ULONG_MAX;
                kbuf.top_down = true;

                ret = kexec_add_buffer(&kbuf);
                if (ret < 0) {
                        vfree(headers);
                        goto out_err;
                }
                image->elf_headers = headers;
                image->elf_load_addr = kbuf.mem;
                image->elf_headers_sz = headers_sz;

                kexec_dprintk("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
                              image->elf_load_addr, kbuf.bufsz, kbuf.memsz);

                /* Add the mem=size@start parameter to the command line */
                cmdline_add_mem(&cmdline_tmplen, modified_cmdline);

                /* Add the elfcorehdr=size@start parameter to the command line */
                cmdline_add_elfcorehdr(image, &cmdline_tmplen, modified_cmdline, headers_sz);
        }
#endif

        /* Load initrd */
        if (initrd) {
                kbuf.buffer = initrd;
                kbuf.bufsz = initrd_len;
                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                kbuf.memsz = initrd_len;
                kbuf.buf_align = 0;
                /* within 1GB-aligned window of up to 32GB in size */
                kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) + (unsigned long)SZ_1G * 32;
                kbuf.top_down = false;

                ret = kexec_add_buffer(&kbuf);
                if (ret < 0)
                        goto out_err;
                initrd_load_addr = kbuf.mem;

                kexec_dprintk("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
                              initrd_load_addr, kbuf.bufsz, kbuf.memsz);

                /* Add the initrd=start,size parameter to the command line */
                cmdline_add_initrd(image, &cmdline_tmplen, modified_cmdline, initrd_load_addr);
        }

        if (cmdline_len + cmdline_tmplen > COMMAND_LINE_SIZE) {
                pr_err("Appending command line exceeds COMMAND_LINE_SIZE\n");
                ret = -EINVAL;
                goto out_err;
        }

        memcpy(modified_cmdline + cmdline_tmplen, cmdline, cmdline_len);
        cmdline = modified_cmdline;
        image->arch.cmdline_ptr = (unsigned long)cmdline;

        return 0;

out_err:
        image->nr_segments = orig_segments;
        kfree(modified_cmdline);
        return ret;
}