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Commit e15dd494 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Matt Fleming
Browse files

efi/arm64: Preserve FP/SIMD registers on UEFI runtime services calls 



According to the UEFI spec section 2.3.6.4, the use of FP/SIMD
instructions is allowed, and should adhere to the AAPCS64 calling
convention, which states that 'only the bottom 64 bits of each value
stored in registers v8-v15 need to be preserved' (section 5.1.2).

This applies equally to UEFI Runtime Services called by the kernel, so
make sure the FP/SIMD register file is preserved in this case. We do this
by enabling the wrappers for UEFI Runtime Services (CONFIG_EFI_RUNTIME_WRAPPERS)
and inserting calls to kernel_neon_begin()and kernel_neon_end() into
these wrappers.

Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 022ee6c5

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -298,6 +298,7 @@ config EFI 
	select LIBFDT

	select UCS2_STRING

	select EFI_PARAMS_FROM_FDT

	select EFI_RUNTIME_WRAPPERS

	default y

	help

	  This option provides support for runtime services provided

arch/arm64/include/asm/efi.h

+21 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
#define _ASM_EFI_H



#include <asm/io.h>

#include <asm/neon.h>



#ifdef CONFIG_EFI

extern void efi_init(void);
@@ -11,4 +12,24 @@ extern void efi_idmap_init(void); 
#define efi_idmap_init()

#endif



#define efi_call_virt(f, ...)						\

({									\

	efi_##f##_t *__f = efi.systab->runtime->f;			\

	efi_status_t __s;						\

									\

	kernel_neon_begin();						\

	__s = __f(__VA_ARGS__);						\

	kernel_neon_end();						\

	__s;								\

})



#define __efi_call_virt(f, ...)						\

({									\

	efi_##f##_t *__f = efi.systab->runtime->f;			\

									\

	kernel_neon_begin();						\

	__f(__VA_ARGS__);						\

	kernel_neon_end();						\

})



#endif /* _ASM_EFI_H */

arch/arm64/kernel/efi.c

+1 −13
Original line number Diff line number Diff line
@@ -449,19 +449,7 @@ static int __init arm64_enter_virtual_mode(void) 


	/* Set up runtime services function pointers */

	runtime = efi.systab->runtime;

	efi.get_time = runtime->get_time;

	efi.set_time = runtime->set_time;

	efi.get_wakeup_time = runtime->get_wakeup_time;

	efi.set_wakeup_time = runtime->set_wakeup_time;

	efi.get_variable = runtime->get_variable;

	efi.get_next_variable = runtime->get_next_variable;

	efi.set_variable = runtime->set_variable;

	efi.query_variable_info = runtime->query_variable_info;

	efi.update_capsule = runtime->update_capsule;

	efi.query_capsule_caps = runtime->query_capsule_caps;

	efi.get_next_high_mono_count = runtime->get_next_high_mono_count;

	efi.reset_system = runtime->reset_system;



	efi_native_runtime_setup();

	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);



	return 0;