u-boot/arch/x86/lib/efi/crt0-efi-ia32.S
Ben Stoltz 3dcdd17b43 x86: Add support for U-Boot as an EFI application
Add the required x86 glue code. This includes the initial start-up,
relocation and jumping to efi_main(). We also need to avoid fiddling with
interrupts.

Signed-off-by: Ben Stoltz <stoltz@google.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2015-08-05 08:44:06 -06:00

52 lines
1 KiB
ArmAsm

/*
* crt0-efi-ia32.S - x86 EFI startup code.
*
* Copyright (C) 1999 Hewlett-Packard Co.
* Contributed by David Mosberger <davidm@hpl.hp.com>.
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
.text
.align 4
.globl _start
_start:
pushl %ebp
movl %esp,%ebp
pushl 12(%ebp) # copy "image" argument
pushl 8(%ebp) # copy "systab" argument
call 0f
0: popl %eax
movl %eax,%ebx
addl $image_base-0b,%eax # %eax = ldbase
addl $_DYNAMIC-0b,%ebx # %ebx = _DYNAMIC
pushl %ebx # pass _DYNAMIC as second argument
pushl %eax # pass ldbase as first argument
call _relocate
popl %ebx
popl %ebx
testl %eax,%eax
jne .exit
call efi_main # call app with "image" and "systab" argument
.exit: leave
ret
/*
* hand-craft a dummy .reloc section so EFI knows it's a relocatable
* executable:
*/
.data
dummy: .long 0
#define IMAGE_REL_ABSOLUTE 0
.section .reloc
.long dummy /* Page RVA */
.long 10 /* Block Size (2*4+2) */
.word (IMAGE_REL_ABSOLUTE << 12) + 0 /* reloc for dummy */