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Date: Fri, 2 May 2014 11:20:34 -0400 From: Mark Salter <msalter@...hat.com> To: Catalin Marinas <catalin.marinas@....com>, Will Deacon <will.deacon@....com> Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, Mark Salter <msalter@...hat.com> Subject: [PATCH 1/2] arm64: fix unnecessary tlb flushes The __cpu_flush_user_tlb_range() and __cpu_flush_user_tlb_range() functions loop through an address range by page to flush tlb entries. However, these functions assume a 4K page size. If the kernel is configured for 64k page sizes, these functions would execute the tlbi instruction 16 times per page rather than once. This patch uses the PAGE_SHIFT definition to ensure one tlb flush for any given page in the range. Signed-off-by: Mark Salter <msalter@...hat.com> --- arch/arm64/mm/tlb.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/tlb.S b/arch/arm64/mm/tlb.S index 19da91e..b818073 100644 --- a/arch/arm64/mm/tlb.S +++ b/arch/arm64/mm/tlb.S @@ -42,7 +42,7 @@ ENTRY(__cpu_flush_user_tlb_range) bfi x0, x3, #48, #16 // start VA and ASID bfi x1, x3, #48, #16 // end VA and ASID 1: tlbi vae1is, x0 // TLB invalidate by address and ASID - add x0, x0, #1 + add x0, x0, #(1 << (PAGE_SHIFT - 12)) cmp x0, x1 b.lo 1b dsb sy @@ -62,7 +62,7 @@ ENTRY(__cpu_flush_kern_tlb_range) lsr x0, x0, #12 // align address lsr x1, x1, #12 1: tlbi vaae1is, x0 // TLB invalidate by address - add x0, x0, #1 + add x0, x0, #(1 << (PAGE_SHIFT - 12)) cmp x0, x1 b.lo 1b dsb sy -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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