[PATCH 2/2] arm64: Check if GMID_EL1.BS is the same on all CPUs

[Catalin Marinas]

On Wed, May 26, 2021 at 08:47:16PM +0100, Jon Hunter wrote:
> On 11/05/2021 19:23, Catalin Marinas wrote:
> > The GMID_EL1.BS field determines the number of tags accessed by the
> > LDGM/STGM instructions (EL1 and up), used by the kernel for copying or
> > zeroing page tags.
> > 
> > Taint the kernel if GMID_EL1.BS differs between CPUs.
> > 
> > Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> > Cc: Will Deacon <will at kernel.org>
> > Cc: Mark Rutland <mark.rutland at arm.com>
> > Cc: Suzuki K Poulose <Suzuki.Poulose at arm.com>
[...]
> I am seeing the following undefined instruction crash on all our 
> ARM64 Tegra devices on today's -next and bisect is pointing to
> this patch. Reverting this patch on top of -next does fix the 
> problem. Let me know if you have any thoughts.

Yeah, sorry about that. Posted a new version here, better tested:

https://lore.kernel.org/r/20210526193621.21559-1-catalin.marinas@arm.com

Will should have dropped the old one from linux-next but it takes a few
hours before Stephen re-creates the tree.

-- 
Catalin