[SRU][Bionic][PATCH 0/2] Fix ThunderX boot issues

[Juerg Haefliger]

On Wed, 15 Jan 2020 18:36:36 +0100
Juerg Haefliger <juerg.haefliger at canonical.com> wrote:

> Two trivial KPTI patches to fix a nasty ThunderX boot issues.
> 
> The 'arm64: add sentinel to kpti_safe_list' patch might not be a
> contributor here but it certainly fixes a real issue since on ThunderX the
> list is traversed all the way to the end and not stopped due to the
> missing sentinel.
> 
> The real problem is fixed by 'arm64: Check for errata before evaluating
> cpu features'. The kernel has a check in place for a certain Cavium errata.
> If that errata is enabled, KPTI is turned off (the code comment mentions
> I-cache clobbering if both are enabled at the same time). Some earlier KPTI
> commit changed the order in which features and erratas are evaluated and
> enabled resulting in a short period of time where both KPTI and that errata
> are enabled. The fix reverses that order.

Correction, KPTI and the erratum are enabled persistently and not just for a
brief period of time.

...Juerg

> Dirk Mueller (1):
>   arm64: Check for errata before evaluating cpu features
> 
> Mark Rutland (1):
>   arm64: add sentinel to kpti_safe_list
> 
>  arch/arm64/kernel/cpufeature.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 

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