From ae8a8b9553bd3906af74ff4e8d763904d20ab4e5 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 3 Apr 2013 17:16:57 +0100 Subject: ARM: 7691/1: mm: kill unused TLB_CAN_READ_FROM_L1_CACHE and use ALT_SMP instead 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 Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/mm/proc-v7.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm/mm/proc-v7.S') diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 3a3c015f8d5..37716b0508e 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -75,14 +75,14 @@ ENTRY(cpu_v7_do_idle) ENDPROC(cpu_v7_do_idle) ENTRY(cpu_v7_dcache_clean_area) -#ifndef TLB_CAN_READ_FROM_L1_CACHE + ALT_SMP(mov pc, lr) @ MP extensions imply L1 PTW + ALT_UP(W(nop)) dcache_line_size r2, r3 1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry add r0, r0, r2 subs r1, r1, r2 bhi 1b dsb -#endif mov pc, lr ENDPROC(cpu_v7_dcache_clean_area) -- cgit v1.2.3-18-g5258