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: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 5a46c4e..375ba34 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -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 @@
#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 */
