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

[Ard Biesheuvel]

On 4 July 2014 18:59, Catalin Marinas <catalin.marinas at arm.com> wrote:
> On Fri, Jul 04, 2014 at 04:51:31PM +0100, Ard Biesheuvel wrote:
>> 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?
>
> No, that's fine. You could just add the above explanation to the commit
> log. Otherwise:
>
> Acked-by: Catalin Marinas <catalin.marinas at arm.com>

OK, thanks. I will add your ack and ask Matt to take it.

-- 
Ard.