AARCH64:Use of EFI_MEMORY_XP

[Evan Lloyd <Evan.Lloyd@arm.com>]

Hi Ard.
We still have a minor problem in that the spec disqualifies EFI_MEMORY_XP for AARCH64.
Do you have any thoughts on this?
How should we proceed here?  I assume the specification statement was a considered decision.
Do we need to get it changed, or is EFI_MEMORY_XP unnecessary?

Regards,
Evan

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Evan Lloyd
> Sent: 08 January 2018 18:51
> To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: "Matteo.Carlini@arm.com"@arm.com;
> "leif.lindholm@linaro.org"@arm.com; "nd@arm.com"@arm.com; edk2-
> devel@lists.01.org; Arvind Chauhan <Arvind.Chauhan@arm.com>;
> "ard.biesheuvel@linaro.org"@arm.com; Thomas Abraham
> <thomas.abraham@arm.com>
> Subject: Re: [edk2] [PATCH edk2-platforms v2 15/18] ARM/VExpressPkg:
> New DP500/DP550/DP650 platform library.
>
>
>
> > -----Original Message-----
> > From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
> > Sent: 23 December 2017 16:07
> > To: Evan Lloyd <Evan.Lloyd@arm.com>
> > Cc: edk2-devel@lists.01.org; Arvind Chauhan
> <Arvind.Chauhan@arm.com>;
> > Daniil Egranov <Daniil.Egranov@arm.com>; Thomas Abraham
> > <thomas.abraham@arm.com>; "ard.biesheuvel@linaro.org"@arm.com;
> > "leif.lindholm@linaro.org"@arm.com;
> > "Matteo.Carlini@arm.com"@arm.com; "nd@arm.com"@arm.com
> > Subject: Re: [PATCH edk2-platforms v2 15/18] ARM/VExpressPkg: New
> > DP500/DP550/DP650 platform library.
> >
...
> > > +  // Mark the VRAM as write-combining. The VRAM is inside the DRAM,
> > > + which is  // cacheable, for ARM/AArch64 EFI_MEMORY_WC memory
> is
> > actually uncached.
> > > +  Status = gDS->SetMemorySpaceAttributes (
> > > +                  *VramBaseAddress,
> > > +                  *VramSize,
> > > +                  EFI_MEMORY_WC
> >
> > Please add EFI_MEMORY_XP here
> >
>
>  [[Evan Lloyd]] We can do that, happily.  However, in looking at this we
> found that the UEFI spec has in "2.3.6 AArch64 Platforms", section "2.3.6.1
> Memory types":
> EFI_MEMORY_XP, ...                                                                             Not used
> or defined
>
> Does that suggest we need a minor spec update?
>
> > > +                  );
...
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