[U-Boot] [PATCH v5] x86: use EFI calling convention for efi_main on x86_64

[Ivan Gorinov]

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.

v5:
  Keeping unused _relocate() arguments, to be submitted as another patch.

v4:
  Keeping .exit label in x86_64 startup code;
  Also removed the unused _relocate() arguments for arm, x86, riscv.

v3:
  Updated patch description.

v2:
  Added EFIABI to _relocate() declaration.

Ivan Gorinov (1):
  x86: use EFI calling convention for efi_main on x86_64

 arch/x86/lib/crt0_x86_64_efi.S | 24 +++++++++++++-----------
 lib/efi/efi_app.c              |  3 ++-
 lib/efi/efi_stub.c             |  3 ++-
 3 files changed, 17 insertions(+), 13 deletions(-)

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2.7.4