efi/arm64: Preserve FP/SIMD registers on UEFI runtime services calls
commite15dd4949a937d8e8482f37f8fe493357417f203
authorArd Biesheuvel <ard.biesheuvel@linaro.org>
Fri, 4 Jul 2014 17:41:53 +0000 (4 19:41 +0200)
committerMatt Fleming <matt.fleming@intel.com>
Mon, 7 Jul 2014 19:29:42 +0000 (7 20:29 +0100)
treed66dba79a540033a0072d7ebfcfa1667783227f2
parent022ee6c558fc933679e151f00f84332974147fa2
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>
arch/arm64/Kconfig
arch/arm64/include/asm/efi.h
arch/arm64/kernel/efi.c