From patchwork Wed Jun 15 17:23:12 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 882852 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p5FHPUmr017631 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 15 Jun 2011 17:25:51 GMT Received: from canuck.infradead.org ([2001:4978:20e::1]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QWtqF-0006n1-2n; Wed, 15 Jun 2011 17:25:23 +0000 Received: from localhost ([127.0.0.1] helo=canuck.infradead.org) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QWtqE-0003qW-HQ; Wed, 15 Jun 2011 17:25:22 +0000 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QWtpq-0003ki-IZ for linux-arm-kernel@lists.infradead.org; Wed, 15 Jun 2011 17:25:00 +0000 Received: from localhost.localdomain (e102144-lin.cambridge.arm.com [10.1.69.60]) by cam-admin0.cambridge.arm.com (8.12.6/8.12.6) with ESMTP id p5FHLwFA026709; Wed, 15 Jun 2011 18:22:23 +0100 (BST) From: Will Deacon To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 1/9] ARM: l2x0: fix disabling function to avoid deadlock Date: Wed, 15 Jun 2011 18:23:12 +0100 Message-Id: <1308158600-7169-2-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 1.7.0.4 MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1308158600-7169-1-git-send-email-will.deacon@arm.com> References: <1308158600-7169-1-git-send-email-will.deacon@arm.com> X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20110615_132458_965344_8FAD9D0B X-CRM114-Status: GOOD ( 12.64 ) X-Spam-Score: -0.0 (/) X-Spam-Report: SpamAssassin version 3.3.1 on canuck.infradead.org summary: Content analysis details: (-0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain Cc: frank.hofmann@tomtom.com, dave.martin@linaro.org, Will Deacon , ccross@android.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Wed, 15 Jun 2011 17:25:52 +0000 (UTC) The l2x0_disable function attempts to writel with the l2x0_lock held. This results in deadlock when the writel contains an outer_sync call for the platform since the l2x0_lock is already held by the disable function. A further problem is that disabling the L2 without flushing it first can lead to the spin_lock operation becoming visible after the spin_unlock, causing any subsequent L2 maintenance to deadlock. This patch replaces the writel with a call to writel_relaxed in the disabling code and adds a flush before disabling in the control register, preventing livelock from occurring. Signed-off-by: Will Deacon Acked-by: Catalin Marinas --- arch/arm/mm/cache-l2x0.c | 19 +++++++++++++------ 1 files changed, 13 insertions(+), 6 deletions(-) diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c index ef59099..44c0867 100644 --- a/arch/arm/mm/cache-l2x0.c +++ b/arch/arm/mm/cache-l2x0.c @@ -120,17 +120,22 @@ static void l2x0_cache_sync(void) spin_unlock_irqrestore(&l2x0_lock, flags); } -static void l2x0_flush_all(void) +static void __l2x0_flush_all(void) { - unsigned long flags; - - /* clean all ways */ - spin_lock_irqsave(&l2x0_lock, flags); debug_writel(0x03); writel_relaxed(l2x0_way_mask, l2x0_base + L2X0_CLEAN_INV_WAY); cache_wait_way(l2x0_base + L2X0_CLEAN_INV_WAY, l2x0_way_mask); cache_sync(); debug_writel(0x00); +} + +static void l2x0_flush_all(void) +{ + unsigned long flags; + + /* clean all ways */ + spin_lock_irqsave(&l2x0_lock, flags); + __l2x0_flush_all(); spin_unlock_irqrestore(&l2x0_lock, flags); } @@ -266,7 +271,9 @@ static void l2x0_disable(void) unsigned long flags; spin_lock_irqsave(&l2x0_lock, flags); - writel(0, l2x0_base + L2X0_CTRL); + __l2x0_flush_all(); + writel_relaxed(0, l2x0_base + L2X0_CTRL); + dsb(); spin_unlock_irqrestore(&l2x0_lock, flags); }