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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009,2011 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Note: These functions defined in this file may be called from C.
* Be careful of that you must not modify some registers. Quote
* from gcc-2.95.2/gcc/config/i386/i386.h:
1 for registers not available across function calls.
These must include the FIXED_REGISTERS and also any
registers that can be used without being saved.
The latter must include the registers where values are returned
and the register where structure-value addresses are passed.
Aside from that, you can include as many other registers as you like.
ax,dx,cx,bx,si,di,bp,sp,st,st1,st2,st3,st4,st5,st6,st7,arg
{ 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
*/
/*
* Note: GRUB is compiled with the options -mrtd and -mregparm=3.
* So the first three arguments are passed in %eax, %edx, and %ecx,
* respectively, and if a function has a fixed number of arguments
* and the number is greater than three, the function must return
* with "ret $N" where N is ((the number of arguments) - 3) * 4.
*/
#include <config.h>
#include <grub/symbol.h>
#include <multiboot.h>
#ifdef __APPLE__
#include <grub/i386/pc/memory.h>
#endif
.file "startup.S"
.text
.globl start, _start, __start
start:
_start:
__start:
#ifdef __APPLE__
LOCAL(start):
#endif
.code32
movl %ecx, (LOCAL(real_to_prot_addr) - _start) (%esi)
movl %edi, (LOCAL(prot_to_real_addr) - _start) (%esi)
movl %eax, (EXT_C(grub_realidt) - _start) (%esi)
/* copy back the decompressed part (except the modules) */
#ifdef __APPLE__
movl $EXT_C(_edata), %ecx
subl $LOCAL(start), %ecx
#else
movl $(_edata - _start), %ecx
#endif
movl $(_start), %edi
rep
movsb
movl $LOCAL (cont), %esi
jmp *%esi
LOCAL(cont):
#if 0
/* copy modules before cleaning out the bss */
movl EXT_C(grub_total_module_size), %ecx
movl EXT_C(grub_kernel_image_size), %esi
addl %ecx, %esi
addl $_start, %esi
decl %esi
movl $END_SYMBOL, %edi
addl %ecx, %edi
decl %edi
std
rep
movsb
#endif
#ifdef __APPLE__
/* clean out the bss */
movl $EXT_C(_edata), %edi
/* compute the bss length */
movl $GRUB_MEMORY_MACHINE_SCRATCH_ADDR, %ecx
#else
/* clean out the bss */
movl $BSS_START_SYMBOL, %edi
/* compute the bss length */
movl $END_SYMBOL, %ecx
#endif
subl %edi, %ecx
/* clean out */
xorl %eax, %eax
cld
rep
stosb
movl %edx, EXT_C(grub_boot_device)
/*
* Call the start of main body of C code.
*/
call EXT_C(grub_main)
LOCAL(real_to_prot_addr):
.long 0
LOCAL(prot_to_real_addr):
.long 0
.macro PROT_TO_REAL
movl LOCAL(prot_to_real_addr), %eax
call *%eax
.endm
.macro REAL_TO_PROT
movl LOCAL(real_to_prot_addr), %eax
calll *%eax
.endm
/*
* grub_exit()
*
* Exit the system.
*/
FUNCTION(grub_exit)
PROT_TO_REAL
.code16
/* Tell the BIOS a boot failure. If this does not work, reboot. */
int $0x18
/* set 0x472 to 0x0000 for cold boot (0x1234 for warm boot) */
xorw %ax, %ax
movw $0x0472, %di
movw %ax, (%di)
ljmp $0xf000, $0xfff0
.code32
/*
* int grub_pxe_call (int func, void* data, grub_uint32_t pxe_rm_entry);
*/
FUNCTION(grub_pxe_call)
pushl %ebp
movl %esp, %ebp
pushl %esi
pushl %edi
pushl %ebx
movl %ecx, %ebx
movl %eax, %ecx
movl %edx, %eax
andl $0xF, %eax
shrl $4, %edx
shll $16, %edx
addl %eax, %edx
PROT_TO_REAL
.code16
pushl %ebx
pushl %edx
pushw %cx
movw %sp, %bx
lcall *%ss:6(%bx)
cld
addw $10, %sp
movw %ax, %cx
REAL_TO_PROT
.code32
movzwl %cx, %eax
popl %ebx
popl %edi
popl %esi
popl %ebp
ret
#include "../int.S"
VARIABLE(grub_realidt)
.long 0
#ifdef __APPLE__
/* Older versions of objconv assume that there is the same number
of text and data sections. Hence this dummy. */
.section __TEXT, __zz_dummy
.byte 0
.globl EXT_C(_edata)
.globl EXT_C(grub_boot_device)
.zerofill __DATA, __aa_before_bss, EXT_C(_edata), 1, 0
.zerofill __DATA, __bss, EXT_C(grub_boot_device), 4, 2
#else
.bss
VARIABLE(grub_boot_device)
.long 0
#endif
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