[PATCH v2 2/2] efi/arm64: preserve FP/SIMD registers on UEFI runtime services calls

[Ard Biesheuvel]

On 4 July 2014 17:45, Catalin Marinas <catalin.marinas at arm.com> wrote:
> On Thu, Jun 26, 2014 at 11:09:06AM +0100, Ard Biesheuvel wrote:
>> 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.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>
> While the code looks fine, I think there is a mismatch between what the
> subject says and what the patch does (enabling EFI_RUNTIME_WRAPPERS).
>

Not entirely. In order to be able to insert calls to
kernel_neon_begin()/end() into the runtime services calls, we need
a) to supply definitions for efi_call_virt() and __efi_call_virt()
that contain those calls to kernel_neon_begin()/end()
b) to enable runtime wrappers (which is what uses those definitions)

Would you prefer those to be split in 2 patches?

--
Ard.