[PATCH v2 0/2] efi: preserve NEON registers on UEFI services calls

[olivier.martin@arm.com (Olivier Martin)]

It is correct the UEFI 2.4 spec says 'Floating point and SIMD instructions may be used'. And it is also correct these registers are not preserved in the current UEFI EDK2 implementation.
I will keep track in ARM UEFI todo list.

Acked-by: Olivier Martin <olivier.martin@arm.com>

Thanks Ard for your patch,
Olivier

> -----Original Message-----
> From: Ard Biesheuvel [mailto:ard.biesheuvel at linaro.org]
> Sent: 01 July 2014 14:46
> To: Matt Fleming
> Cc: Matt Fleming; x86 at kernel.org; Catalin Marinas; linux-
> efi at vger.kernel.org; linux-arm-kernel at lists.infradead.org;
> hpa at zytor.com; Leif Lindholm; Roy Franz; msalter at redhat.com; Olivier
> Martin
> Subject: Re: [PATCH v2 0/2] efi: preserve NEON registers on UEFI
> services calls
> 
> On 1 July 2014 15:26, Matt Fleming <matt@console-pimps.org> wrote:
> > On Thu, 26 Jun, at 12:09:04PM, Ard Biesheuvel wrote:
> >> The current UEFI implementation for arm64 fails to preserve/restore
> the contents
> >> of the NEON register file, which may result in data corruption,
> especially now
> >> that those contents are lazily restored for user processes.
> >>
> >> This series proposes to fix this by wrapping all runtime services
> calls, and
> >> adding kernel_neon_begin()/kernel_neon_end() pairs to the wrappers.
> >>
> >> The first patch moves the existing x86 versions of those wrappers to
> generic
> >> code, so that the second patch can easily enable them by supplying a
> definition
> >> for efi_call_virt and adding a call to efi_native_runtime_setup().
> >>
> >> Changes since v1:
> >> - rename runtime.c -> runtime-wrappers.c
> >> - make build depend on new Kconfig symbol EFI_RUNTIME_WRAPPERS to
> fix ia64
> >>   breakage
> >> - remove default #defines for efi_call_virt()/__efi_call_virt(),
> they are not
> >>   needed anymore now that it is built conditionally
> >> - add references to applicable UEFI/AAPCS spec sections
> >>
> >> Ard Biesheuvel (2):
> >>   efi/x86: move UEFI Runtime Services wrappers to generic code
> >>   efi/arm64: preserve FP/SIMD registers on UEFI runtime services
> calls
> >
> > Thanks Ard. These patches look OK to me, and I've now pulled them
> into
> > my 'next' branch.
> >
> > It'd be nice if we could get some ACKs from other people since this
> is
> > an ABI issue.
> 
> Yes, they have been awfully quiet, haven't they?
> 
> At least Roy has volunteered to get involved in the USWG to get the
> spec clarified.
> 
> @Leif, Catalin, Olivier: care to chime in?
> 
> --
> Ard.