Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755242AbbHNOFQ (ORCPT ); Fri, 14 Aug 2015 10:05:16 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:37043 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754567AbbHNOFO (ORCPT ); Fri, 14 Aug 2015 10:05:14 -0400 Message-ID: <55CDF579.4050408@ti.com> Date: Fri, 14 Aug 2015 10:04:41 -0400 From: Murali Karicheri Organization: Texas Instruments User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: , , , Subject: Re: [PATCH] ARM: keystone: add a work around to handle asynchronous external abort References: <1439320409-20084-1-git-send-email-m-karicheri2@ti.com> In-Reply-To: <1439320409-20084-1-git-send-email-m-karicheri2@ti.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2519 Lines: 76 On 08/11/2015 03:13 PM, Murali Karicheri wrote: > Currently on some devices, an asynchronous external abort exception > happens during boot up when exception handlers are enabled in kernel > before switching to user space. This patch adds a workaround to handle > this once during boot. Many customers are already using this > with out any issues and is required to workaround the above issue. > > Signed-off-by: Murali Karicheri > --- > arch/arm/mach-keystone/keystone.c | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+) > > diff --git a/arch/arm/mach-keystone/keystone.c b/arch/arm/mach-keystone/keystone.c > index e2880105..c1d0fe5 100644 > --- a/arch/arm/mach-keystone/keystone.c > +++ b/arch/arm/mach-keystone/keystone.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -52,6 +53,24 @@ static struct notifier_block platform_nb = { > .notifier_call = keystone_platform_notifier, > }; > > +static bool ignore_first = true; > +static int keystone_async_ext_abort_fault(unsigned long addr, unsigned int fsr, > + struct pt_regs *regs) > +{ > + /* > + * if first time, ignore this as this is a asynchronous external abort > + * happening only some devices that couldn't be root caused and we add > + * this work around to handle this first time. > + */ > + if (ignore_first) { > + ignore_first = false; > + return 0; > + } > + > + /* Subsequent ones should be handled as fault */ > + return 1; > +} > + > static void __init keystone_init(void) > { > if (PHYS_OFFSET >= KEYSTONE_HIGH_PHYS_START) { > @@ -61,6 +80,13 @@ static void __init keystone_init(void) > } > keystone_pm_runtime_init(); > of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL); > + > + /* > + * Add a one time exception handler to catch asynchronous external > + * abort > + */ > + hook_fault_code(17, keystone_async_ext_abort_fault, SIGBUS, 0, > + "async external abort handler"); > } > > static phys_addr_t keystone_virt_to_idmap(unsigned long x) > Can this be applied if it looks good? Murali -- Murali Karicheri Linux Kernel, Keystone -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/