// SPDX-License-Identifier: GPL-2.0-only
/*
 * Load ELF vmlinux file for the kexec_file_load syscall.
 *
 * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
 * Copyright (C) 2004  IBM Corp.
 * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
 * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
 * Copyright (C) 2016  IBM Corporation
 *
 * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
 * Heavily modified for the kernel by
 * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
 */

#define pr_fmt(fmt)     "kexec_elf: " fmt

#include <linux/elf.h>
#include <linux/kexec.h>
#include <linux/libfdt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <asm/kexec_ranges.h>

static void *elf64_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;
        unsigned long kernel_load_addr;
        unsigned long initrd_load_addr = 0, fdt_load_addr;
        void *fdt;
        const void *slave_code;
        struct elfhdr ehdr;
        char *modified_cmdline = NULL;
        struct crash_mem *rmem = NULL;
        struct kexec_elf_info elf_info;
        struct kexec_buf kbuf = { .image = image, .buf_min = 0,
                                  .buf_max = ppc64_rma_size };
        struct kexec_buf pbuf = { .image = image, .buf_min = 0,
                                  .buf_max = ppc64_rma_size, .top_down = true,
                                  .mem = KEXEC_BUF_MEM_UNKNOWN };

        ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
        if (ret)
                return ERR_PTR(ret);

        if (IS_ENABLED(CONFIG_CRASH_DUMP) && image->type == KEXEC_TYPE_CRASH) {
                /* min & max buffer values for kdump case */
                kbuf.buf_min = pbuf.buf_min = crashk_res.start;
                kbuf.buf_max = pbuf.buf_max =
                                ((crashk_res.end < ppc64_rma_size) ?
                                 crashk_res.end : (ppc64_rma_size - 1));
        }

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

        kexec_dprintk("Loaded the kernel at 0x%lx\n", kernel_load_addr);

        ret = kexec_load_purgatory(image, &pbuf);
        if (ret) {
                pr_err("Loading purgatory failed.\n");
                goto out;
        }

        kexec_dprintk("Loaded purgatory at 0x%lx\n", pbuf.mem);

        /* Load additional segments needed for panic kernel */
        if (IS_ENABLED(CONFIG_CRASH_DUMP) && image->type == KEXEC_TYPE_CRASH) {
                ret = load_crashdump_segments_ppc64(image, &kbuf);
                if (ret) {
                        pr_err("Failed to load kdump kernel segments\n");
                        goto out;
                }

                /* Setup cmdline for kdump kernel case */
                modified_cmdline = setup_kdump_cmdline(image, cmdline,
                                                       cmdline_len);
                if (!modified_cmdline) {
                        pr_err("Setting up cmdline for kdump kernel failed\n");
                        ret = -EINVAL;
                        goto out;
                }
                cmdline = modified_cmdline;
        }

        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;
                initrd_load_addr = kbuf.mem;

                kexec_dprintk("Loaded initrd at 0x%lx\n", initrd_load_addr);
        }

        ret = get_reserved_memory_ranges(&rmem);
        if (ret)
                goto out;

        fdt = of_kexec_alloc_and_setup_fdt(image, initrd_load_addr,
                                           initrd_len, cmdline,
                                           kexec_extra_fdt_size_ppc64(image, rmem));
        if (!fdt) {
                pr_err("Error setting up the new device tree.\n");
                ret = -EINVAL;
                goto out;
        }

        ret = setup_new_fdt_ppc64(image, fdt, rmem);
        if (ret)
                goto out_free_fdt;

        if (!IS_ENABLED(CONFIG_CRASH_HOTPLUG) || image->type != KEXEC_TYPE_CRASH)
                fdt_pack(fdt);

        kbuf.buffer = fdt;
        kbuf.bufsz = kbuf.memsz = fdt_totalsize(fdt);
        kbuf.buf_align = PAGE_SIZE;
        kbuf.top_down = true;
        kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
        ret = kexec_add_buffer(&kbuf);
        if (ret)
                goto out_free_fdt;

        /* FDT will be freed in arch_kimage_file_post_load_cleanup */
        image->arch.fdt = fdt;

        fdt_load_addr = kbuf.mem;

        kexec_dprintk("Loaded device tree at 0x%lx\n", fdt_load_addr);

        slave_code = elf_info.buffer + elf_info.proghdrs[0].p_offset;
        ret = setup_purgatory_ppc64(image, slave_code, fdt, kernel_load_addr,
                                    fdt_load_addr);
        if (ret)
                pr_err("Error setting up the purgatory.\n");

        goto out;

out_free_fdt:
        kvfree(fdt);
out:
        kfree(rmem);
        kfree(modified_cmdline);
        kexec_free_elf_info(&elf_info);

        return ret ? ERR_PTR(ret) : NULL;
}

const struct kexec_file_ops kexec_elf64_ops = {
        .probe = kexec_elf_probe,
        .load = elf64_load,
};