u-boot/arch/x86/lib/crt0_x86_64_efi.S
Ivan Gorinov 9f0b0113c9 x86: use EFI calling convention for efi_main on x86_64
UEFI specifies the calling convention used in Microsoft compilers;
first arguments of a function are passed in (%rcx, %rdx, %r8, %r9).

All other compilers use System V ABI by default, passing first integer
arguments of a function in (%rdi, %rsi, %rdx, %rcx, %r8, %r9).

These ABI also specify different sets of registers that must be preserved
across function calls (callee-saved).

GCC allows using the Microsoft calling convention by adding the ms_abi
attribute to a function declaration.

Current EFI implementation in U-Boot specifies EFIAPI for efi_main()
in the test apps but uses default calling convention in lib/efi.

Save efi_main() arguments in the startup code on x86_64;
use EFI calling convention for _relocate() on x86_64;
consistently use EFI calling convention for efi_main() everywhere.

Signed-off-by: Ivan Gorinov <ivan.gorinov@intel.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2018-06-17 21:16:04 +08:00

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ArmAsm

/* SPDX-License-Identifier: BSD-3-Clause */
/*
* crt0-efi-x86_64.S - x86_64 EFI startup code.
* Copyright (C) 1999 Hewlett-Packard Co.
* Contributed by David Mosberger <davidm@hpl.hp.com>.
* Copyright (C) 2005 Intel Corporation
* Contributed by Fenghua Yu <fenghua.yu@intel.com>.
*
* All rights reserved.
*/
.text
.align 4
.globl _start
_start:
subq $8, %rsp
pushq %rcx
pushq %rdx
mov %rcx, %r8
mov %rdx, %r9
lea image_base(%rip), %rcx
lea _DYNAMIC(%rip), %rdx
call _relocate
popq %rdx
popq %rcx
testq %rax, %rax
jnz .exit
call efi_main
.exit:
addq $8, %rsp
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, "a"
label1:
.long dummy-label1 /* Page RVA */
.long 10 /* Block Size (2*4+2) */
.word (IMAGE_REL_ABSOLUTE << 12) + 0 /* reloc for dummy */