// SPDX-License-Identifier: GPL-2.0
/*
 * Load ELF vmlinux file for the kexec_file_load syscall.
 *
 * Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
 *
 */
#include <linux/elf.h>
#include <linux/kexec.h>
#include <linux/libfdt.h>
#include <linux/module.h>
#include <linux/of_fdt.h>
#include <linux/slab.h>
#include <linux/types.h>

static void *elf_load(struct kimage *image, char *kernel_buf,
                        unsigned long kernel_len, char *initrd,
                        unsigned long initrd_len, char *cmdline,
                        unsigned long cmdline_len)
{
        int ret, i;
        unsigned long kernel_load_addr;
        struct elfhdr ehdr;
        struct kexec_elf_info elf_info;
        struct kexec_buf kbuf = { .image = image, .buf_min = 0,
                                  .buf_max = -1UL, };

        ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
        if (ret)
                goto out;

        ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr);
        if (ret)
                goto out;

        image->start = __pa(elf_info.ehdr->e_entry);

        for (i = 0; i < image->nr_segments; i++)
                image->segment[i].mem = __pa(image->segment[i].mem);

        kexec_dprintk("Loaded the kernel at 0x%lx, entry at 0x%lx\n",
                      kernel_load_addr, image->start);

        if (initrd != NULL) {
                kbuf.buffer = initrd;
                kbuf.bufsz = kbuf.memsz = initrd_len;
                kbuf.buf_align = PAGE_SIZE;
                kbuf.top_down = false;
                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                ret = kexec_add_buffer(&kbuf);
                if (ret)
                        goto out;

                kexec_dprintk("Loaded initrd at 0x%lx\n", kbuf.mem);
                image->arch.initrd_start = kbuf.mem;
                image->arch.initrd_end = kbuf.mem + initrd_len;
        }

        if (cmdline != NULL) {
                kbuf.buffer = cmdline;
                kbuf.bufsz = kbuf.memsz = ALIGN(cmdline_len, 8);
                kbuf.buf_align = PAGE_SIZE;
                kbuf.top_down = false;
                kbuf.buf_min = PAGE0->mem_free + PAGE_SIZE;
                kbuf.buf_max = kernel_load_addr;
                kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
                ret = kexec_add_buffer(&kbuf);
                if (ret)
                        goto out;

                kexec_dprintk("Loaded cmdline at 0x%lx\n", kbuf.mem);
                image->arch.cmdline = kbuf.mem;
        }
out:
        return NULL;
}

const struct kexec_file_ops kexec_elf_ops = {
        .probe = kexec_elf_probe,
        .load = elf_load,
};

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