Re: [U-Boot] [PATCH v3] x86: use EFI calling convention for efi_main on x86_64

On Thu, May 31, 2018 at 9:46 PM, Ivan Gorinov ivan.gorinov@intel.com wrote:

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. The arguments of efi_main() are also passed as unused arguments to the _relocate() function.

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

Thanks, FWIW,

Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com

Signed-off-by: Ivan Gorinov ivan.gorinov@intel.com

arch/x86/lib/crt0_x86_64_efi.S | 21 ++++++++++----------- arch/x86/lib/reloc_x86_64_efi.c | 3 +-- lib/efi/efi_app.c | 3 ++- lib/efi/efi_stub.c | 3 ++- 4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/x86/lib/crt0_x86_64_efi.S b/arch/x86/lib/crt0_x86_64_efi.S index 989799f..3abb5e3 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 +14,25 @@ .globl _start _start: subq $8, %rsp

•   pushq %rcx
    pushq %rdx
  
  

-0:

•   lea image_base(%rip), %rdi
  

•   lea _DYNAMIC(%rip), %rsi
  

•   lea image_base(%rip), %rcx
  

•   lea _DYNAMIC(%rip), %rdx
  
  

•   popq %rcx
  

•   popq %rdx
  

•   pushq %rcx
  

•   pushq %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

    /*

diff --git a/arch/x86/lib/reloc_x86_64_efi.c b/arch/x86/lib/reloc_x86_64_efi.c index 34c5b2e..59d6f8d 100644 --- a/arch/x86/lib/reloc_x86_64_efi.c +++ b/arch/x86/lib/reloc_x86_64_efi.c @@ -14,8 +14,7 @@ #include <elf.h> #include <asm/elf.h>

-efi_status_t _relocate(long ldbase, Elf64_Dyn *dyn, efi_handle_t image,

•                  struct efi_system_table *systab)
  

+efi_status_t EFIAPI _relocate(long ldbase, Elf64_Dyn *dyn) { long relsz = 0, relent = 0; Elf64_Rel *rel = 0; diff --git a/lib/efi/efi_app.c b/lib/efi/efi_app.c index c828093..3eb8eeb 100644 --- a/lib/efi/efi_app.c +++ b/lib/efi/efi_app.c @@ -96,7 +96,8 @@ static void free_memory(struct efi_priv *priv)

• U-Boot. If it returns, EFI will continue. Another way to get back to EFI
• is via reset_cpu().

*/ -efi_status_t efi_main(efi_handle_t image, struct efi_system_table *sys_table) +efi_status_t EFIAPI efi_main(efi_handle_t image,

•                        struct efi_system_table *sys_table)
  

{ struct efi_priv local_priv, *priv = &local_priv; efi_status_t ret; diff --git a/lib/efi/efi_stub.c b/lib/efi/efi_stub.c index 3138739..399d16b 100644 --- a/lib/efi/efi_stub.c +++ b/lib/efi/efi_stub.c @@ -268,7 +268,8 @@ static void add_entry_addr(struct efi_priv *priv, enum efi_entry_t type,

• This function is called by our EFI start-up code. It handles running
• U-Boot. If it returns, EFI will continue.

*/ -efi_status_t efi_main(efi_handle_t image, struct efi_system_table *sys_table) +efi_status_t EFIAPI efi_main(efi_handle_t image,

•                        struct efi_system_table *sys_table)
  

{ struct efi_priv local_priv, *priv = &local_priv; struct efi_boot_services *boot = sys_table->boottime; -- 2.7.4

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