From patchwork Mon Mar 25 18:19:40 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 2333131 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id EA9493FD8C for ; Mon, 25 Mar 2013 18:31:56 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UKC8e-0006wh-Mx; Mon, 25 Mar 2013 18:28:56 +0000 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UKBzu-0001Xh-NW for linux-arm-kernel@lists.infradead.org; Mon, 25 Mar 2013 18:19:59 +0000 Received: from mudshark.cambridge.arm.com (mudshark.cambridge.arm.com [10.1.79.58]) by cam-admin0.cambridge.arm.com (8.12.6/8.12.6) with ESMTP id r2PIJoki013065; Mon, 25 Mar 2013 18:19:50 GMT Received: by mudshark.cambridge.arm.com (Postfix, from userid 1000) id 82D59C2B17; Mon, 25 Mar 2013 18:19:42 +0000 (GMT) From: Will Deacon To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 3/4] ARM: mm: kill unused TLB_CAN_READ_FROM_L1_CACHE and use ALT_SMP instead Date: Mon, 25 Mar 2013 18:19:40 +0000 Message-Id: <1364235581-17900-4-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 1.8.0 In-Reply-To: <1364235581-17900-1-git-send-email-will.deacon@arm.com> References: <1364235581-17900-1-git-send-email-will.deacon@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130325_141955_262257_593EF4D1 X-CRM114-Status: GOOD ( 12.79 ) X-Spam-Score: -8.2 (--------) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-8.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [217.140.96.50 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.3 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Will Deacon X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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 Signed-off-by: Will Deacon Reviewed-by: Catalin Marinas --- arch/arm/include/asm/tlbflush.h | 2 +- arch/arm/mm/proc-v6.S | 2 -- arch/arm/mm/proc-v7-2level.S | 3 ++- arch/arm/mm/proc-v7-3level.S | 3 ++- arch/arm/mm/proc-v7.S | 4 ++-- 5 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h index c7cdb59..42d155e 100644 --- a/arch/arm/include/asm/tlbflush.h +++ b/arch/arm/include/asm/tlbflush.h @@ -169,7 +169,7 @@ # define v6wbi_always_flags (-1UL) #endif -#define v7wbi_tlb_flags_smp (TLB_WB | TLB_DCLEAN | TLB_BARRIER | \ +#define v7wbi_tlb_flags_smp (TLB_WB | TLB_BARRIER | \ TLB_V6_U_FULL | TLB_V6_U_PAGE | \ TLB_V6_U_ASID | TLB_V6_BP | \ TLB_V7_UIS_FULL | TLB_V7_UIS_PAGE | \ diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S index bcaaa8d..a286d47 100644 --- a/arch/arm/mm/proc-v6.S +++ b/arch/arm/mm/proc-v6.S @@ -80,12 +80,10 @@ ENTRY(cpu_v6_do_idle) mov pc, lr ENTRY(cpu_v6_dcache_clean_area) -#ifndef TLB_CAN_READ_FROM_L1_CACHE 1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry add r0, r0, #D_CACHE_LINE_SIZE subs r1, r1, #D_CACHE_LINE_SIZE bhi 1b -#endif mov pc, lr /* diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S index 78f520b..9704097 100644 --- a/arch/arm/mm/proc-v7-2level.S +++ b/arch/arm/mm/proc-v7-2level.S @@ -110,7 +110,8 @@ ENTRY(cpu_v7_set_pte_ext) ARM( str r3, [r0, #2048]! ) THUMB( add r0, r0, #2048 ) THUMB( str r3, [r0] ) - mcr p15, 0, r0, c7, c10, 1 @ flush_pte + ALT_SMP(mov pc,lr) + ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte #endif mov pc, lr ENDPROC(cpu_v7_set_pte_ext) diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S index 6ffd78c..363027e 100644 --- a/arch/arm/mm/proc-v7-3level.S +++ b/arch/arm/mm/proc-v7-3level.S @@ -73,7 +73,8 @@ ENTRY(cpu_v7_set_pte_ext) tst r3, #1 << (55 - 32) @ L_PTE_DIRTY orreq r2, #L_PTE_RDONLY 1: strd r2, r3, [r0] - mcr p15, 0, r0, c7, c10, 1 @ flush_pte + ALT_SMP(mov pc, lr) + ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte #endif mov pc, lr ENDPROC(cpu_v7_set_pte_ext) diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 3a3c015..37716b0 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)