From patchwork Mon Jan 6 21:35:33 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hauke Mehrtens X-Patchwork-Id: 3440791 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 7C1D29F1C4 for ; Mon, 6 Jan 2014 21:38:33 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A668820179 for ; Mon, 6 Jan 2014 21:38:32 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A466B2016D for ; Mon, 6 Jan 2014 21:38:31 +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 1W0Hqu-0005Gz-Fr; Mon, 06 Jan 2014 21:36:53 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1W0Hqb-0005mn-Dm; Mon, 06 Jan 2014 21:36:33 +0000 Received: from hauke-2-pt.tunnel.tserv6.fra1.ipv6.he.net ([2001:470:1f0a:465::2] helo=hauke-m.de) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1W0HqN-0005k0-RZ for linux-arm-kernel@lists.infradead.org; Mon, 06 Jan 2014 21:36:21 +0000 Received: from localhost (localhost [127.0.0.1]) by hauke-m.de (Postfix) with ESMTP id 1BBB58F62; Mon, 6 Jan 2014 22:36:01 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at hauke-m.de Received: from hauke-m.de ([127.0.0.1]) by localhost (hauke-m.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EZ+6lIlnbALq; Mon, 6 Jan 2014 22:35:55 +0100 (CET) Received: from hauke-desktop.lan (spit-414.wohnheim.uni-bremen.de [134.102.133.158]) by hauke-m.de (Postfix) with ESMTPSA id B48328F65; Mon, 6 Jan 2014 22:35:37 +0100 (CET) From: Hauke Mehrtens To: arnd@arndb.de Subject: [PATCH v6 4/4] ARM: BCM5301X: workaround suppress fault Date: Mon, 6 Jan 2014 22:35:33 +0100 Message-Id: <1389044133-27394-5-git-send-email-hauke@hauke-m.de> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1389044133-27394-1-git-send-email-hauke@hauke-m.de> References: <1389044133-27394-1-git-send-email-hauke@hauke-m.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140106_163620_211638_7D8A250D X-CRM114-Status: GOOD ( 17.35 ) X-Spam-Score: -1.9 (-) Cc: thomas.petazzoni@free-electrons.com, f.fainelli@gmail.com, Hauke Mehrtens , bcm@fixthebug.org, will.deacon@arm.com, cavokz@gmail.com, matt.porter@linaro.org, linux-arm-kernel@lists.infradead.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: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.5 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 Without this patch I am getting a unhandled fault exception like this one after "Freeing unused kernel memory": Freeing unused kernel memory: 1260K (c02c1000 - c03fc000) Unhandled fault: imprecise external abort (0x1c06) at 0xb6f89005 Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000007 The address which is here 0xb6f89005 changes from boot to boot, with a new build the changes are bigger. With kernel 3.10 I have also seen this fault at different places in the boot process, but starting with 3.11 they are always occurring after the "Freeing unused kernel memory" message. I never was able to completely boot to userspace without this handler. The abort code is constant 0x1c06. This fault just happens once in the boot process I have never seen it happing twice or more. I also tried changing the CPSR.A bit to 0 in init_early, with this code like Afzal suggested, but that did not change anything: asm volatile("mrs r12, cpsr\n" "bic r12, r12, #0x00000100\n" "msr cpsr_c, r12" ::: "r12", "cc", "memory"); Disabling the L2 cache by building with CONFIG_CACHE_L2X0 unset did not help. This workaround was copied from the vendor code including most of the comments. It says it they think this is caused by the CFE boot loader used on this device. I do not have any access to any datasheet or errata document to check this. Signed-off-by: Hauke Mehrtens Acked-by: Arnd Bergmann --- arch/arm/mach-bcm/bcm_5301x.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/arch/arm/mach-bcm/bcm_5301x.c b/arch/arm/mach-bcm/bcm_5301x.c index ef9740a..edff6976 100644 --- a/arch/arm/mach-bcm/bcm_5301x.c +++ b/arch/arm/mach-bcm/bcm_5301x.c @@ -9,8 +9,40 @@ #include #include +#include +#include +static bool first_fault = true; + +static int bcm5301x_abort_handler(unsigned long addr, unsigned int fsr, + struct pt_regs *regs) +{ + if (fsr == 0x1c06 && first_fault) { + first_fault = false; + + /* + * These faults with code 0x1c06 happens for no good reason, + * possibly left over from the CFE boot loader. + */ + pr_warn("External imprecise Data abort at addr=%#lx, fsr=%#x ignored.\n", + addr, fsr); + + /* Returning non-zero causes fault display and panic */ + return 0; + } + + /* Others should cause a fault */ + return 1; +} + +static void __init bcm5301x_init_early(void) +{ + /* Install our hook */ + hook_fault_code(16 + 6, bcm5301x_abort_handler, SIGBUS, BUS_OBJERR, + "imprecise external abort"); +} + static void __init bcm5301x_dt_init(void) { l2x0_of_init(0, ~0UL); @@ -23,6 +55,7 @@ static const char __initconst *bcm5301x_dt_compat[] = { }; DT_MACHINE_START(BCM5301X, "BCM5301X") + .init_early = bcm5301x_init_early, .init_machine = bcm5301x_dt_init, .dt_compat = bcm5301x_dt_compat, MACHINE_END