From patchwork Wed Oct 16 03:34:46 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Pitre X-Patchwork-Id: 3050031 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 2D2ACBF924 for ; Wed, 16 Oct 2013 03:35:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 22E6A203E9 for ; Wed, 16 Oct 2013 03:35:27 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CD10620259 for ; Wed, 16 Oct 2013 03:35:25 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VWHtK-0004hU-K8; Wed, 16 Oct 2013 03:35:22 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VWHtI-0005Iq-8v; Wed, 16 Oct 2013 03:35:20 +0000 Received: from mail-qe0-f43.google.com ([209.85.128.43]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VWHtE-0005IL-SP for linux-arm-kernel@lists.infradead.org; Wed, 16 Oct 2013 03:35:17 +0000 Received: by mail-qe0-f43.google.com with SMTP id nc12so150891qeb.2 for ; Tue, 15 Oct 2013 20:34:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:user-agent :mime-version:content-type; bh=h+cjTNq5iUQG23CVxeuSeKii2sEQ+r4OCGE89hIY9jw=; b=hps632bu+vJgGRMvWWIP/lyBSAFJSEd7QiraNEOXtG4QQbGoSPABprjtQuyzIg+qEy MBIvU6qPjb6jq6/Gepk9zRbJi7dSj9P8tjNS1D/X/OAhM7HFXXUGr+Rkz+s4KjvrhQoi r8kazULYe4gi2/cg4gVwDKj0sVECb28vwQJjcC/8p5AbEfR0u7Ig45wxaqYl1gMUQr6d dWxCvKaayfPgr5bXK046soEyJIyg7i/WrixFMrMkYjEtjKB+YjmUYP0zcWqHye4lE2xK D4V/nOTtWnE1tKY25wAQkCqvRYEOn6pcrh8OpFiI1VjXJKyON6+V06Y0/DDCrE46+o27 vLMg== X-Gm-Message-State: ALoCoQmSq8b70ckn3TPm7vBRQM/hvsC7b29vxJ9h+9fNaIwdg+xrc9MvruDVHRGWgcvBs516LltY X-Received: by 10.49.3.199 with SMTP id e7mr891079qee.10.1381894493193; Tue, 15 Oct 2013 20:34:53 -0700 (PDT) Received: from xanadu.home (modemcable177.143-130-66.mc.videotron.ca. [66.130.143.177]) by mx.google.com with ESMTPSA id g2sm163196075qaf.12.1969.12.31.16.00.00 (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 15 Oct 2013 20:34:52 -0700 (PDT) Date: Tue, 15 Oct 2013 23:34:46 -0400 (EDT) From: Nicolas Pitre To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] ARM: cacheflush: consolidate single-CPU ARMv7 cache disabling code Message-ID: User-Agent: Alpine 2.03 (LFD 1266 2009-07-14) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131015_233517_000480_F6A57996 X-CRM114-Status: GOOD ( 17.53 ) X-Spam-Score: -2.6 (--) Cc: Lorenzo Pieralisi , Dave Martin , patches@linaro.org 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This code is becoming duplicated in many places. So let's consolidate it into a handy macro that is known to be right and available for reuse. Signed-off-by: Nicolas Pitre --- I forgot which version this one is. As far as I know, I've incorporated most review comments, and ignored conflicting ones which tended to look like bikeshedding and attempted to compensate for them with additional code comments. ACK? arch/arm/include/asm/cacheflush.h | 45 +++++++++++++++++++++++++++++++ arch/arm/mach-vexpress/dcscb.c | 56 +++------------------------------------ arch/arm/mach-vexpress/tc2_pm.c | 48 ++------------------------------- 3 files changed, 51 insertions(+), 98 deletions(-) diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h index 15f2d5bf88..60a0a79b1a 100644 --- a/arch/arm/include/asm/cacheflush.h +++ b/arch/arm/include/asm/cacheflush.h @@ -435,4 +435,49 @@ static inline void __sync_cache_range_r(volatile void *p, size_t size) #define sync_cache_w(ptr) __sync_cache_range_w(ptr, sizeof *(ptr)) #define sync_cache_r(ptr) __sync_cache_range_r(ptr, sizeof *(ptr)) +/* + * Disabling cache access for one CPU in an ARMv7 SMP system is tricky. + * To do so we must: + * + * - Clear the SCTLR.C bit to prevent further cache allocations + * - Flush the desired level of cache + * - Clear the ACTLR "SMP" bit to disable local coherency + * + * ... and so without any intervening memory access in between those steps, + * not even to the stack. + * + * WARNING -- After this has been called: + * + * - No ldrex/strex (and similar) instructions must be used. + * - The CPU is obviously no longer coherent with the other CPUs. + * - This is unlikely to work as expected if Linux is running non-secure. + * + * Note: + * + * - This is known to apply to several ARMv7 processor implementations, + * however some exceptions may exist. Caveat emptor. + * + * - The clobber list is dictated by the call to v7_flush_dcache_*. + * fp is preserved to the stack explicitly prior disabling the cache + * since adding it to the clobber list is incompatible with having + * CONFIG_FRAME_POINTER=y. + */ +#define v7_exit_coherency_flush(level) \ + asm volatile( \ + "str fp, [sp, #-4]! \n\t" \ + "mrc p15, 0, r0, c1, c0, 0 @ get SCTLR \n\t" \ + "bic r0, r0, #"__stringify(CR_C)" \n\t" \ + "mcr p15, 0, r0, c1, c0, 0 @ set SCTLR \n\t" \ + "isb \n\t" \ + "bl v7_flush_dcache_"__stringify(level)" \n\t" \ + "clrex \n\t" \ + "mrc p15, 0, r0, c1, c0, 1 @ get ACTLR \n\t" \ + "bic r0, r0, #(1 << 6) @ disable local coherency \n\t" \ + "mcr p15, 0, r0, c1, c0, 1 @ set ACTLR \n\t" \ + "isb \n\t" \ + "dsb \n\t" \ + "ldr fp, [sp], #4" \ + : : : "r0","r1","r2","r3","r4","r5","r6","r7", \ + "r9","r10","lr","memory" ) + #endif diff --git a/arch/arm/mach-vexpress/dcscb.c b/arch/arm/mach-vexpress/dcscb.c index 3a6384c6c4..14d4996887 100644 --- a/arch/arm/mach-vexpress/dcscb.c +++ b/arch/arm/mach-vexpress/dcscb.c @@ -133,38 +133,8 @@ static void dcscb_power_down(void) if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) { arch_spin_unlock(&dcscb_lock); - /* - * Flush all cache levels for this cluster. - * - * To do so we do: - * - Clear the SCTLR.C bit to prevent further cache allocations - * - Flush the whole cache - * - Clear the ACTLR "SMP" bit to disable local coherency - * - * Let's do it in the safest possible way i.e. with - * no memory access within the following sequence - * including to the stack. - * - * Note: fp is preserved to the stack explicitly prior doing - * this since adding it to the clobber list is incompatible - * with having CONFIG_FRAME_POINTER=y. - */ - asm volatile( - "str fp, [sp, #-4]! \n\t" - "mrc p15, 0, r0, c1, c0, 0 @ get CR \n\t" - "bic r0, r0, #"__stringify(CR_C)" \n\t" - "mcr p15, 0, r0, c1, c0, 0 @ set CR \n\t" - "isb \n\t" - "bl v7_flush_dcache_all \n\t" - "clrex \n\t" - "mrc p15, 0, r0, c1, c0, 1 @ get AUXCR \n\t" - "bic r0, r0, #(1 << 6) @ disable local coherency \n\t" - "mcr p15, 0, r0, c1, c0, 1 @ set AUXCR \n\t" - "isb \n\t" - "dsb \n\t" - "ldr fp, [sp], #4" - : : : "r0","r1","r2","r3","r4","r5","r6","r7", - "r9","r10","lr","memory"); + /* Flush all cache levels for this cluster. */ + v7_exit_coherency_flush(all); /* * This is a harmless no-op. On platforms with a real @@ -183,26 +153,8 @@ static void dcscb_power_down(void) } else { arch_spin_unlock(&dcscb_lock); - /* - * Flush the local CPU cache. - * Let's do it in the safest possible way as above. - */ - asm volatile( - "str fp, [sp, #-4]! \n\t" - "mrc p15, 0, r0, c1, c0, 0 @ get CR \n\t" - "bic r0, r0, #"__stringify(CR_C)" \n\t" - "mcr p15, 0, r0, c1, c0, 0 @ set CR \n\t" - "isb \n\t" - "bl v7_flush_dcache_louis \n\t" - "clrex \n\t" - "mrc p15, 0, r0, c1, c0, 1 @ get AUXCR \n\t" - "bic r0, r0, #(1 << 6) @ disable local coherency \n\t" - "mcr p15, 0, r0, c1, c0, 1 @ set AUXCR \n\t" - "isb \n\t" - "dsb \n\t" - "ldr fp, [sp], #4" - : : : "r0","r1","r2","r3","r4","r5","r6","r7", - "r9","r10","lr","memory"); + /* Disable and flush the local CPU cache. */ + v7_exit_coherency_flush(louis); } __mcpm_cpu_down(cpu, cluster); diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c index e6eb481929..4eb92ebfd9 100644 --- a/arch/arm/mach-vexpress/tc2_pm.c +++ b/arch/arm/mach-vexpress/tc2_pm.c @@ -156,32 +156,7 @@ static void tc2_pm_down(u64 residency) : : "r" (0x400) ); } - /* - * We need to disable and flush the whole (L1 and L2) cache. - * Let's do it in the safest possible way i.e. with - * no memory access within the following sequence - * including the stack. - * - * Note: fp is preserved to the stack explicitly prior doing - * this since adding it to the clobber list is incompatible - * with having CONFIG_FRAME_POINTER=y. - */ - asm volatile( - "str fp, [sp, #-4]! \n\t" - "mrc p15, 0, r0, c1, c0, 0 @ get CR \n\t" - "bic r0, r0, #"__stringify(CR_C)" \n\t" - "mcr p15, 0, r0, c1, c0, 0 @ set CR \n\t" - "isb \n\t" - "bl v7_flush_dcache_all \n\t" - "clrex \n\t" - "mrc p15, 0, r0, c1, c0, 1 @ get AUXCR \n\t" - "bic r0, r0, #(1 << 6) @ disable local coherency \n\t" - "mcr p15, 0, r0, c1, c0, 1 @ set AUXCR \n\t" - "isb \n\t" - "dsb \n\t" - "ldr fp, [sp], #4" - : : : "r0","r1","r2","r3","r4","r5","r6","r7", - "r9","r10","lr","memory"); + v7_exit_coherency_flush(all); cci_disable_port_by_cpu(mpidr); @@ -197,26 +172,7 @@ static void tc2_pm_down(u64 residency) arch_spin_unlock(&tc2_pm_lock); - /* - * We need to disable and flush only the L1 cache. - * Let's do it in the safest possible way as above. - */ - asm volatile( - "str fp, [sp, #-4]! \n\t" - "mrc p15, 0, r0, c1, c0, 0 @ get CR \n\t" - "bic r0, r0, #"__stringify(CR_C)" \n\t" - "mcr p15, 0, r0, c1, c0, 0 @ set CR \n\t" - "isb \n\t" - "bl v7_flush_dcache_louis \n\t" - "clrex \n\t" - "mrc p15, 0, r0, c1, c0, 1 @ get AUXCR \n\t" - "bic r0, r0, #(1 << 6) @ disable local coherency \n\t" - "mcr p15, 0, r0, c1, c0, 1 @ set AUXCR \n\t" - "isb \n\t" - "dsb \n\t" - "ldr fp, [sp], #4" - : : : "r0","r1","r2","r3","r4","r5","r6","r7", - "r9","r10","lr","memory"); + v7_exit_coherency_flush(louis); } __mcpm_cpu_down(cpu, cluster);