/*-
 * Copyright (c) 2001 Benno Rice <benno@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#define __ELF_WORD_SIZE 64

#include <sys/param.h>
#include <sys/endian.h>
#include <sys/linker.h>

#include <machine/metadata.h>
#include <machine/elf.h>

#include <stand.h>

#include "bootstrap.h"
#include "syscall_nr.h"
#include "host_syscall.h"
#include "modinfo.h"
#include "kboot.h"

extern char             end[];
extern void             *kerneltramp;
extern size_t           szkerneltramp;

struct trampoline_data {
        uint32_t        kernel_entry;
        uint32_t        dtb;
        uint32_t        phys_mem_offset;
        uint32_t        of_entry;
        uint32_t        mdp;
        uint32_t        mdp_size;
};

int
ppc64_elf_loadfile(char *filename, uint64_t dest,
    struct preloaded_file **result)
{
        int     r;

        r = __elfN(loadfile)(filename, dest, result);
        if (r != 0)
                return (r);

        return (0);
}

int
ppc64_elf_exec(struct preloaded_file *fp)
{
        struct file_metadata    *fmp;
        vm_offset_t             mdp, dtb;
        Elf_Ehdr                *e;
        int                     error;
        uint32_t                *trampoline;
        uint64_t                entry;
        uint64_t                trampolinebase;
        struct trampoline_data  *trampoline_data;
        int                     nseg;
        void                    *kseg;

        if ((fmp = file_findmetadata(fp, MODINFOMD_ELFHDR)) == NULL) {
                return(EFTYPE);
        }
        e = (Elf_Ehdr *)&fmp->md_data;

        /*
         * Figure out where to put it.
         *
         * Linux does not allow us to do kexec_load into any part of memory. Ask
         * kboot_get_phys_load_segment to resolve the first available chunk of
         * physical memory where loading is possible (load_addr).
         *
         * Memory organization is shown below.  It is assumed, that text segment
         * offset of kernel ELF (KERNPHYSADDR) is non-zero, which is true for
         * PPC/PPC64 architectures, where default is 0x100000.
         *
         * load_addr:                 trampoline code
         * load_addr + KERNPHYSADDR:  kernel text segment
         */
        trampolinebase = kboot_get_phys_load_segment();
        printf("Load address at %#jx\n", (uintmax_t)trampolinebase);
        printf("Relocation offset is %#jx\n", (uintmax_t)elf64_relocation_offset);

        /* Set up loader trampoline */
        trampoline = malloc(szkerneltramp);
        memcpy(trampoline, &kerneltramp, szkerneltramp);

        /* Parse function descriptor for ELFv1 kernels */
        if ((e->e_flags & 3) == 2)
                entry = e->e_entry;
        else {
                archsw.arch_copyout(e->e_entry + elf64_relocation_offset,
                    &entry, 8);
                entry = be64toh(entry);
        }

        /*
         * Placeholder for trampoline data is at trampolinebase + 0x08
         * CAUTION: all data must be Big Endian
         */
        trampoline_data = (void*)&trampoline[2];
        trampoline_data->kernel_entry = htobe32(entry + elf64_relocation_offset);
        trampoline_data->phys_mem_offset = htobe32(0);
        trampoline_data->of_entry = htobe32(0);

        if ((error = md_load64(fp->f_args, &mdp, &dtb)) != 0)
                return (error);

        trampoline_data->dtb = htobe32(dtb);
        trampoline_data->mdp = htobe32(mdp);
        trampoline_data->mdp_size = htobe32(0xfb5d104d);

        printf("Kernel entry at %#jx (%#x) ...\n",
            entry, be32toh(trampoline_data->kernel_entry));
        printf("DTB at %#x, mdp at %#x\n",
            be32toh(trampoline_data->dtb), be32toh(trampoline_data->mdp));

        dev_cleanup();

        archsw.arch_copyin(trampoline, trampolinebase, szkerneltramp);
        free(trampoline);

        kboot_kseg_get(&nseg, &kseg);

        error = host_kexec_load(trampolinebase, nseg, kseg, HOST_KEXEC_ARCH_PPC64);
        if (error != 0)
                panic("kexec_load returned error: %d", error);

        error = host_reboot(HOST_REBOOT_MAGIC1, HOST_REBOOT_MAGIC2, HOST_REBOOT_CMD_KEXEC,
            (uintptr_t)NULL);
        if (error != 0)
                panic("reboot returned error: %d", error);

        while (1) {}
}

struct file_format      ppc_elf64 = {
        .l_load = ppc64_elf_loadfile,
        .l_exec = ppc64_elf_exec
};

/*
 * Sort formats so that those that can detect based on arguments rather than
 * reading the file first.
 */

struct file_format *file_formats[] = {
    &ppc_elf64,
    NULL
};