Commit 89ed4865 authored Jan 03, 2020 by Ard Biesheuvel Committed by Ingo Molnar Jan 10, 2020

efi/x86: Avoid redundant cast of EFI firmware service pointer



All EFI firmware call prototypes have been annotated as __efiapi,
permitting us to attach attributes regarding the calling convention
by overriding __efiapi to an architecture specific value.

On 32-bit x86, EFI firmware calls use the plain calling convention
where all arguments are passed via the stack, and cleaned up by the
caller. Let's add this to the __efiapi definition so we no longer
need to cast the function pointers before invoking them.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Matthew Garrett <mjg59@google.com>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20200103113953.9571-6-ardb@kernel.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent ffc2760b

arch/x86/include/asm/efi.h

+1 −7

Original line number	Diff line number	Diff line
		@@ -51,13 +51,7 @@ extern asmlinkage unsigned long efi_call_phys(void *, ...);
		})


		/*
		* Wrap all the virtual calls in a way that forces the parameters on the stack.
		*/
		#define arch_efi_call_virt(p, f, args...) \
		({ \
		((efi_##f##_t __attribute__((regparm(0)))*) p->f)(args); \
		})
		#define arch_efi_call_virt(p, f, args...) p->f(args)

		#define efi_ioremap(addr, size, type, attr) ioremap_cache(addr, size)

include/linux/efi.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -48,8 +48,10 @@ typedef u16 efi_char16_t; /* UNICODE character */
		typedef u64 efi_physical_addr_t;
		typedef void *efi_handle_t;

		#ifdef CONFIG_X86_64
		#if defined(CONFIG_X86_64)
		#define __efiapi __attribute__((ms_abi))
		#elif defined(CONFIG_X86_32)
		#define __efiapi __attribute__((regparm(0)))
		#else
		#define __efiapi
		#endif

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