/*-
 * Copyright (c) 1998 Michael Smith <msmith@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.
 */

#include <sys/param.h>
#include <sys/exec.h>
#include <sys/linker.h>
#include <string.h>
#define _MACHINE_ELF_WANT_32BIT
#include <i386/include/bootinfo.h>
#include <i386/include/elf.h>
#include <stand.h>

#include "bootstrap.h"
#include "libuserboot.h"

static int      elf32_exec(struct preloaded_file *amp);
static int      elf32_obj_exec(struct preloaded_file *amp);

struct file_format i386_elf = {
        .l_load = elf32_loadfile,
        .l_exec = elf32_exec
};
struct file_format i386_elf_obj = {
        .l_load = elf32_obj_loadfile,
        .l_exec = elf32_obj_exec
};

#define GUEST_STACK     0x1000          /* Initial stack base */
#define GUEST_GDT       0x3000          /* Address of initial GDT */

/*
 * There is an ELF kernel and one or more ELF modules loaded.  
 * We wish to start executing the kernel image, so make such 
 * preparations as are required, and do so.
 */
static int
elf32_exec(struct preloaded_file *fp)
{
        struct file_metadata    *md;
        Elf_Ehdr                *ehdr;
        vm_offset_t             entry, bootinfop, modulep, kernend;
        int                     boothowto, err, bootdev;
        uint32_t                stack[1024], *sp;


        if ((md = file_findmetadata(fp, MODINFOMD_ELFHDR)) == NULL)
                return(EFTYPE);
        ehdr = (Elf_Ehdr *)&(md->md_data);

        err = bi_load32(fp->f_args, &boothowto, &bootdev, &bootinfop, &modulep, &kernend);
        if (err != 0)
                return(err);
        entry = ehdr->e_entry & 0xffffff;

#ifdef DEBUG
        printf("Start @ 0x%lx ...\n", entry);
#endif

        dev_cleanup();

        /*
         * Build a scratch stack at physical 0x1000
         */
        memset(stack, 0, sizeof(stack));
        sp = (uint32_t *)((char *)stack + sizeof(stack));
        *--sp = kernend;
        *--sp = modulep;
        *--sp = bootinfop;
        *--sp = 0;
        *--sp = 0;
        *--sp = 0;
        *--sp = bootdev;
        *--sp = boothowto;

        /*
         * Fake return address to mimic "new" boot blocks.  For more
         * details see recover_bootinfo in locore.S.
         */
        *--sp = 0xbeefface;
        CALLBACK(copyin, stack, GUEST_STACK, sizeof(stack));
        CALLBACK(setreg, 4, (char *)sp - (char *)stack + GUEST_STACK);

        CALLBACK(setgdt, GUEST_GDT, 8 * 4 - 1);

        CALLBACK(exec, entry);

        panic("exec returned");
}

static int
elf32_obj_exec(struct preloaded_file *fp)
{
        return (EFTYPE);
}