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

[Jon Hunter]

On 26/05/2021 22:48, Catalin Marinas wrote:
> 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.


No problem. Thanks for the quick fix!

Jon

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