[PATCH v4 16/20] arm64: enable Permission Indirection Extension (PIE)

[Oliver Upton]

On Tue, Jun 20, 2023 at 09:27:18PM +0100, Mark Brown wrote:
> On Tue, Jun 20, 2023 at 09:16:05PM +0200, Neil Armstrong wrote:
> 
> > This patch on linux-next causes a great amount of:
> 
> > X     xxx.xxxxxx Emulated RAZ for ID register: ISS 0x36002f
> 
> > messages printed by the system firmware on the Qualcomm SM8550 SoC,
> > and the platform is barely usable.
> 
> Regardless of what the kernel is doing it looks like there's a firmware
> issue here, all otherwise undefined registers in the ID space should be
> RAZ so spamming the logs like this isn't great.

Agreed. This isn't a kernel issue... We already do 2 ID register reads
in __cpu_setup(), so can't really blame this change for adding a third.

This stinks of Gunyah:

https://github.com/quic/gunyah-hypervisor/blob/3d4014404993939f898018cfb1935c2d9bfc2830/hyp/vm/vcpu/aarch64/src/sysreg_traps.c#L1177

-- 
Thanks,
Oliver