[PATCH 3/4] ARM: mm: kill unused TLB_CAN_READ_FROM_L1_CACHE and use ALT_SMP instead

[catalin.marinas@arm.com (Catalin Marinas)]

On Mon, Mar 25, 2013 at 06:19:40PM +0000, Will Deacon wrote:
> Many ARMv7 cores have hardware page table walkers that can read the L1
> cache. This is discoverable from the ID_MMFR3 register, although this
> can be expensive to access from the low-level set_pte functions and is a
> pain to cache, particularly with multi-cluster systems.
> 
> A useful observation is that the multi-processing extensions for ARMv7
> require coherent table walks, meaning that we can make use of ALT_SMP
> patching in proc-v7-* to patch away the cache flush safely for these
> cores.
> 
> Reported-by: Albin Tonnerre <Albin.Tonnerre@arm.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

There are some pmd flushing functions we should target as well
(flush_pmd_entry, clean_pmd_entry) in this patch or a new one.

-- 
Catalin