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/* $OpenBSD: pxe_call.S,v 1.2 2005/03/12 21:52:02 tom Exp $ */
/* $NetBSD: pxe_call.S,v 1.2 2002/03/27 17:24:22 kanaoka Exp $ */
/*
* Copyright 2001 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Jason R. Thorpe for Wasabi Systems, Inc.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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.
*/
/*
* Low level PXE BIOS call glue.
*/
#include <machine/asm.h>
#include <assym.h>
#include "gidt.h"
ENTRY(pxecall_bangpxe)
.code32
pushl %ebp
movl %esp, %ebp
pushl %ebx
pushl %ecx
pushl %edx
/* For simplicity, just move all 32 bits. */
movl 8(%ebp), %ebx
pushw _C_LABEL(pxe_command_buf_seg)
pushw _C_LABEL(pxe_command_buf_off)
pushw %bx
call prot_to_real /* Enter real mode */
.code16
sti
/* The encoding is: 0x9a offlo offhi seglo seghi */
lcall $0, $0xffff
.globl _C_LABEL(bangpxe_off)
_C_LABEL(bangpxe_off) = . - 4
.globl _C_LABEL(bangpxe_seg)
_C_LABEL(bangpxe_seg) = . - 2
cli
call real_to_prot /* Leave real mode */
.code32
add $6, %esp
popl %edx
popl %ecx
popl %ebx
popl %ebp
ret
ENTRY(pxecall_pxenv)
.code32
pushl %ebp
movl %esp, %ebp
pushl %ebx
pushl %ecx
pushl %edx
pushl %edi
/* For simplicity, just move all 32 bits. */
movl 8(%ebp), %ebx
call prot_to_real /* Enter real mode */
.code16
/* prot_to_real() has already set %es to BOOTSEG */
lea _C_LABEL(pxe_command_buf), %di
/* The encoding is: 0x9a offlo offhi seglo seghi */
lcall $0, $0xffff
.globl _C_LABEL(pxenv_off)
_C_LABEL(pxenv_off) = . - 4
.globl _C_LABEL(pxenv_seg)
_C_LABEL(pxenv_seg) = . - 2
call real_to_prot /* Leave real mode */
.code32
popl %edi
popl %edx
popl %ecx
popl %ebx
popl %ebp
ret
/*
* prot_to_real()
*
* Switch the processor back into real mode.
*/
.globl prot_to_real
prot_to_real:
.code32
ljmp $S16TEXT, $p2r16 - LINKADDR
p2r16:
.code16
movw $S16DATA, %ax
movw %ax, %ds
movw %ax, %es
movl %cr0, %eax /* Disable protected mode */
andl $~CR0_PE, %eax
movl %eax, %cr0
/* reload real cs:ip */
data32 ljmp $(LINKADDR >> 4), $p2r16real - LINKADDR
p2r16real:
xorw %ax, %ax /* Reset segment registers: */
movw %ax, %ds /* %ds: so we can get at Idtr_real */
movw %ax, %ss /* %ss: for our stack */
.extern Idtr_real
data32 addr32 lidt Idtr_real; /* Set up IDT for real mode */
movw %cs, %ax
movw %ax, %ds
movw %ax, %es /* Set %ds = %es = %cs */
/*
* We were called from 32-bit mode, so there's a 32-bit
* return address on the stack. No segment. This is within
* the flat memory model, so we need to adjust it back so
* that it's relative to our 16-bit %cs.
*/
popl %eax
subl $LINKADDR, %eax
pushw %ax
ret
/*
* real_to_prot()
*
* Switch the processor back into protected mode.
*/
.globl real_to_prot
real_to_prot:
.code16
movw $LINKADDR >> 4, %ax /* We're linked to LINKADDR/16:0000 */
movw %ax, %ds
addr32 lgdt (Gdtr - LINKADDR) /* Reload the GDT */
movl %cr0, %eax /* Enable protected mode */
orl $CR0_PE, %eax
movl %eax, %cr0
data32 ljmp $S32TEXT, $r2p32 /* Reload %cs, flush pipeline */
r2p32:
.code32
/* Reload 32-bit %ds, %ss, %es */
movl $S32DATA, %eax
mov %ax, %ds
mov %ax, %ss
mov %ax, %es
/* Load IDT for debugger and DOS/BIOS interface */
.extern Idtr
lidt Idtr
xorl %eax, %eax
popw %ax /* 16-bit return addr on stack */
addl $LINKADDR, %eax
pushl %eax /* Now have correct 32-bit ret addr */
ret
.end
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