Re: [PATCH] [arm64/tlb] Fix mmu notifiers for range-based invalidates

[Ivan T. Ivanov]

Hi,

On 03-04 00:51, Piotr Jaroszynski wrote:
> 
> Update the __flush_tlb_range_op macro not to modify its parameters as
> these are unexepcted semantics. In practice, this fixes the call to
> mmu_notifier_arch_invalidate_secondary_tlbs() in
> __flush_tlb_range_nosync() to use the correct range instead of an empty
> range with start=end. The empty range was (un)lucky as it results in
> taking the invalidate-all path that doesn't cause correctness issues,
> but can certainly result in suboptimal perf.
> 
> This has been broken since commit 6bbd42e2df8f ("mmu_notifiers: call
> invalidate_range() when invalidating TLBs") when the call to the
> notifiers was added to __flush_tlb_range(). It predates the addition of
> the __flush_tlb_range_op() macro from commit 360839027a6e ("arm64: tlb:
> Refactor the core flush algorithm of __flush_tlb_range") that made the
> bug hard to spot.
> 
> Fixes: 6bbd42e2df8f ("mmu_notifiers: call invalidate_range() when invalidating TLBs")

I think that strictly speaking this should be:

Fixes: 360839027a6e ("arm64: tlb: Refactor the core flush algorithm of __flush_tlb_range")

Regards,
Ivan