/*      $NetBSD: bootxx.S,v 1.12 2022/03/06 18:35:43 mlelstv Exp $      */

/*-
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by David Laight.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <machine/asm.h>
#include <sys/bootblock.h>

/*
 * Code linked to 0xa00 and copied to sectors 2+ of the netbsd boot
 * partition by MI /usr/sbin/installboot.
 * Read into memory by code in pbr.S
 *
 * On entry:
 *      %dl                     BIOS drive number
 *      %edi:%esi               Sector number of NetBSD partition
 *      %cs, %ds, %es, %ss      All zero
 *      %sp                     near 0xfffc
 */
        .text
        .code16
ENTRY(bootxx)
        jmp     1f
        .balign 4
ENTRY(bootxx_magic)
        .long   X86_BOOT_MAGIC_1        /* checked by installboot & pbr code */
boot_params:                            /* space for patchable variables */
        .long   1f - boot_params        /* length of this data area */
#include <boot_params.S>
        . = bootxx + 0x80               /* Space for patching unknown params */

1:      call    gdt_fixup

        calll   real_to_prot
        .code32

        push    %edi
        movl    $_end, %ecx             /* zero bss */
        movl    $__bss_start, %edi
        subl    %edi, %ecx
        shr     $2, %ecx                /* _end and __bss_start are aligned */
        xor     %eax, %eax
        rep
        stosl
        pop     %edi

        movzbl  %dl, %edx
        push    %edi                    /* save args for secondary bootstrap */
        push    %esi
        movl    %esp, %esi              /* address of sector number */
        push    %edx
        push    %esi                    /* args for boot1 */
        push    %edx
        call    _C_LABEL(boot1)         /* C code to load /boot */
        add     $8, %esp
        movw    errno, %dx
        call    prot_to_real
        .code16

        test    %ax, %ax
        jnz     boot_fail

        pop     %edx                    /* bios disk number */
        pop     %ebx                    /* expected partition start sector */
        pop     %ecx
        movl    $boot_params, %esi
        orb     $X86_BP_FLAGS_LBA64VALID, 4(%esi)
        lcall   $SECONDARY_LOAD_ADDRESS/16, $0

boot_fail:
        push    %ax                     /* error string from boot1 */
        movw    %dx, %ax
        aam                             /* largest errno is < 100 */
        addw    $('0' << 8) | '0', %ax  /* to ascii */
        rorw    $8, %ax
        cmpb    $'0', %al               /* suppress leading zero */
        jne     10f
        movb    $' ', %al
10:     movw    %ax, 12f
        movw    $11f, %si
        call    message                 /* output boot failed message */
        pop     %si
        call    message                 /* and text from boot1 */
        jmp     loopstop
11:     .ascii  "Boot failed (errno "
12:     .asciz  "xx): "

ENTRY(_rtt)
        .code32
        call    prot_to_real
        .code16
loopstop:
        movb    0x86, %ah               /* delay for about a second */
        movw    $16, %cx
        int     $0x15
        int     $0x18                   /* might be a boot fail entry */
1:      sti                             /* if not loopstop */
        hlt
        jmp     1b

        /*
         * Vector the fs calls through here so we can support multiple
         * file system types with one copy of the library code and
         * multiple copies of this file.
         */
        .global xxfs_open, xxfs_close, xxfs_read, xxfs_stat
        .code32
xxfs_open:      jmp     XXfs_open
xxfs_close:     jmp     XXfs_close
xxfs_read:      jmp     XXfs_read
xxfs_stat:      jmp     XXfs_stat