Re: [RFC][PATCH 04/11] asm-generic/tlb: Provide generic VIPT cache flush

[Will Deacon]

On Thu, Sep 13, 2018 at 11:21:14AM +0200, Peter Zijlstra wrote:
> The one obvious thing SH and ARM want is a sensible default for
> tlb_start_vma(). (also: https://lkml.org/lkml/2004/1/15/6 )
> 
> Avoid all VIPT architectures providing their own tlb_start_vma()
> implementation and rely on architectures to provide a no-op
> flush_cache_range() when it is not relevant.
> 
> The below makes tlb_start_vma() default to flush_cache_range(), which
> should be right and sufficient. The only exceptions that I found where
> (oddly):
> 
>   - m68k-mmu
>   - sparc64
>   - unicore
> 
> Those architectures appear to have flush_cache_range(), but their
> current tlb_start_vma() does not call it.
> 
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Nick Piggin <npiggin@xxxxxxxxx>
> Cc: David Miller <davem@xxxxxxxxxxxxx>
> Cc: Guan Xuetao <gxt@xxxxxxxxxx>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> ---
>  arch/arc/include/asm/tlb.h      |    9 ---------
>  arch/mips/include/asm/tlb.h     |    9 ---------
>  arch/nds32/include/asm/tlb.h    |    6 ------
>  arch/nios2/include/asm/tlb.h    |   10 ----------
>  arch/parisc/include/asm/tlb.h   |    5 -----
>  arch/sparc/include/asm/tlb_32.h |    5 -----
>  arch/xtensa/include/asm/tlb.h   |    9 ---------
>  include/asm-generic/tlb.h       |   19 +++++++++++--------
>  8 files changed, 11 insertions(+), 61 deletions(-)

LGTM and makes no difference to arm/arm64:

Acked-by: Will Deacon <will.deacon@xxxxxxx>

Will