[PATCH V2] arm64: mm: Optimise tlb flush logic where we have >4K granule

[Will Deacon]

On Fri, May 02, 2014 at 11:37:14AM +0100, Steve Capper wrote:
> The tlb maintainence functions: __cpu_flush_user_tlb_range and
> __cpu_flush_kern_tlb_range do not take into consideration the page
> granule when looping through the address range, and repeatedly flush
> tlb entries for the same page when operating with 64K pages.
> 
> This patch re-works the logic s.t. we instead advance the loop by
>  1 << (PAGE_SHIFT - 12), so avoid repeating ourselves.
> 
> Also the routines have been converted from assembler to static inline
> functions to aid with legibility and potential compiler optimisations.
> 
> Signed-off-by: Steve Capper <steve.capper at linaro.org>
> Acked-by: Will Deacon <will.deacon at arm.com>
> ---
> Changed in V2: added the missing isb(.) to the kernel tlb flush.

Hold your horses ;)

You mentioned remapping kernel text rw/ro, but if you think about it, it's
still executable for both of these, so the isb() isn't needed. Do we have a
case for changing whether or not something is executable?

Will