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>
diff --git a/arch/x86/lib/crt0_x86_64_efi.S b/arch/x86/lib/crt0_x86_64_efi.S
index 989799f..bb8d3cf 100644
--- a/arch/x86/lib/crt0_x86_64_efi.S
+++ b/arch/x86/lib/crt0_x86_64_efi.S
@@ -3,7 +3,7 @@
* 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 Co.
+ * Copyright (C) 2005 Intel Corporation
* Contributed by Fenghua Yu <fenghua.yu@intel.com>.
*
* All rights reserved.
@@ -14,26 +14,28 @@
.globl _start
_start:
subq $8, %rsp
+
pushq %rcx
pushq %rdx
-0:
- lea image_base(%rip), %rdi
- lea _DYNAMIC(%rip), %rsi
+ mov %rcx, %r8
+ mov %rdx, %r9
- popq %rcx
- popq %rdx
- pushq %rcx
- pushq %rdx
+ lea image_base(%rip), %rcx
+ lea _DYNAMIC(%rip), %rdx
+
call _relocate
- popq %rdi
- popq %rsi
+ popq %rdx
+ popq %rcx
+
+ testq %rax, %rax
+ jnz .exit
call efi_main
+.exit:
addq $8, %rsp
-.exit:
ret
/*