Re: [meta-arm] fvp-base doesn't support armv8.2

On Tue, Jun 10, 2025 at 7:49 AM Marek Bykowski via
lists.yoctoproject.org
<[email protected]> wrote:
>
> I forked off the scarthgap branch some time ago (SHA1 commit and date
> below), parked and recently resumed my work on it.
>
> $ git branch -r --contains a8fe9d22eaefc294f91096c6a32663e2f4ab3b10
>   origin/scarthgap
> $ git log --format=format:%cd -1 a8fe9d22eaefc294f91096c6a32663e2f4ab3b10
> Mon Jan 6 06:00:11 2025 -0500
>
> My goal is to have a Cortex-A55 simulated which is armv8.2.
>
> I followed Ross's suggestion
>
> meta-arm-bsp/recipes-bsp/u-boot/u-boot-fvp-base.inc
>
> -EXTRA_OEMAKE += "ARM_ARCH_MAJOR=8 ARM_ARCH_MINOR=4"
> +EXTRA_OEMAKE += "ARM_ARCH_MAJOR=8 ARM_ARCH_MINOR=2"
>
> and it worked. Seeing the model booted up to Linux prompt.
>
> Connected with arm ds and the midr_el1 shows me this MIDR_EL1 0x410FD0F0 32 RO.
> Implementer Arm Limited. 8 RO
> Variant 0x0 4 RO
> Architecture Architectural features are individually identified in the
> ID_* registers. 4 RO
> PartNum 0xD0F 12 RO
> Revision 0x0 4 RO

It's much easier to look at lscpu output or /proc/cpuinfo on a running fvp
For example,
# cat /proc/cpuinfo
processor : 0
BogoMIPS : 200.00
Features : fp asimd evtstrm crc32 atomics fphp asimdhp cpuid asimdrdm
jscvt fcma lrcpc dcpop asimddp asimdfhm dit uscat ilrcpc flagm sb paca
pacg dcpodp flagm2 frint bti
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd0f
CPU revision : 0

> I guess for the ARM AEM models there is really no way to read it back
> if the model implements version 8.2, isn' it?

I'm sure there is a way, but I don't know off the top of my head.



>
> On Tue, 10 Jun 2025 at 12:42, Marek <[email protected]> wrote:
> >
> > Thanks Jon and Ross!
> >
> > On Mon, 9 Jun 2025 at 15:54, Ross Burton <[email protected]> wrote:
> > >
> > > On 8 Jun 2025, at 21:14, Marek Bykowski via lists.yoctoproject.org <[email protected]> wrote:
> > > >
> > > > When I simply change to "require conf/machine/include/arm/arch-armv8-2a.inc" and "FVP_CONFIG[cluster0.has_arm_v8-2] = "1"" and "FVP_CONFIG[cluster1.has_arm_v8-2] = "1" " the FVP_Base_RevC-2xAEMvA doesn't boot at all. I do not see even a single line of log even from bl1. Would that mean the SW stack/Yocto doesn't support armv8.2 for fvp-base model platform?
> > >
> > > If you’re using a recent meta-arm which sets the base-fvp to v8.4 cores, then you didn’t also tell TF-A to use 8.2 and it might have been trying to use 8.4 instructions.  See this in the TF-A recipe:
> > >
> > > EXTRA_OEMAKE += "ARM_ARCH_MAJOR=8 ARM_ARCH_MINOR=4”
> > >
> > > Ross
> >
> >
> >
> > --
> > Slán,
> > Marek
>
>
>
> --
> Slán,
> Marek
>
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