Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753152AbbHNVzo (ORCPT ); Fri, 14 Aug 2015 17:55:44 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:33698 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751987AbbHNVzm (ORCPT ); Fri, 14 Aug 2015 17:55:42 -0400 Message-ID: <55CE63BD.2060107@ti.com> Date: Fri, 14 Aug 2015 17:55:09 -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: Lucas Stach , Russell King - ARM Linux CC: , , 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> <55CDF579.4050408@ti.com> <20150814140934.GX7557@n2100.arm.linux.org.uk> <1439562059.13210.61.camel@pengutronix.de> In-Reply-To: <1439562059.13210.61.camel@pengutronix.de> Content-Type: text/plain; charset="utf-8"; 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: 4170 Lines: 128 On 08/14/2015 10:20 AM, Lucas Stach wrote: > Hi Russell, > > Am Freitag, den 14.08.2015, 15:09 +0100 schrieb Russell King - ARM > Linux: > > [...] > >> >> What causes the abort? We shouldn't be adding hacks like this to the >> kernel without having the full picture... >> > > some of the issues with tracking down such imprecise external aborts are > due to the fact that we only enable the signaling of those aborts on > entering the user-space. So the first schedule() crashes on the previous > dangling abort. > > I'm carrying this patch locally to enable imprecise aborts much earlier > in the boot process. I think it has already been on the list some times, > but apparently it has fallen through the cracks. If you agree that this > is the right thing to do I can do a proper repost. Lucas, Would you mind sharing the code? Does that help in root causing where it actually happens? I have spend considerable time debugging this, but so far not successful. Murali > > Regards, > Lucas > > ---------------------->8--------------------------------------------- >>From bb9117d94cc2f1061dc364f42c446ccd9191e869 Mon Sep 17 00:00:00 2001 > From: Lucas Stach > Date: Thu, 19 Feb 2015 18:12:50 +0100 > Subject: [PATCH] ARM: Add imprecise abort enable/disable macro > > This patch adds imprecise abort enable/disable macros. > It also enables imprecise aborts when starting kernel. > > Changes in v2: > Only ARMv6 and later have CPSR.A bit. On earlier CPUs, > and ARMv7M this should be a no-op. > > Signed-off-by: Fabrice Gasnier > Signed-off-by: Lucas Stach > --- > lst: rebased on v3.19 > --- > arch/arm/include/asm/irqflags.h | 10 ++++++++++ > arch/arm/kernel/smp.c | 1 + > arch/arm/kernel/traps.c | 4 ++++ > 3 files changed, 15 insertions(+) > > diff --git a/arch/arm/include/asm/irqflags.h > b/arch/arm/include/asm/irqflags.h > index 3b763d6652a0..8301f875564e 100644 > --- a/arch/arm/include/asm/irqflags.h > +++ b/arch/arm/include/asm/irqflags.h > @@ -51,6 +51,14 @@ static inline void arch_local_irq_disable(void) > > #define local_fiq_enable() __asm__("cpsie f @ __stf" : : : "memory", > "cc") > #define local_fiq_disable() __asm__("cpsid f @ __clf" : : : "memory", > "cc") > + > +#ifndef CONFIG_CPU_V7M > +#define local_abt_enable() __asm__("cpsie a @ __sta" : : : "memory", > "cc") > +#define local_abt_disable() __asm__("cpsid a @ __cla" : : : "memory", > "cc") > +#else > +#define local_abt_enable() do { } while (0) > +#define local_abt_disable() do { } while (0) > +#endif > #else > > /* > @@ -130,6 +138,8 @@ static inline void arch_local_irq_disable(void) > : "memory", "cc"); \ > }) > > +#define local_abt_enable() do { } while (0) > +#define local_abt_disable() do { } while (0) > #endif > > /* > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > index 86ef244c5a24..7b6b93cabef4 100644 > --- a/arch/arm/kernel/smp.c > +++ b/arch/arm/kernel/smp.c > @@ -378,6 +378,7 @@ asmlinkage void secondary_start_kernel(void) > > local_irq_enable(); > local_fiq_enable(); > + local_abt_enable(); > > /* > * OK, it's off to the idle thread for us > diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c > index 788e23fe64d8..466726ba9bdb 100644 > --- a/arch/arm/kernel/traps.c > +++ b/arch/arm/kernel/traps.c > @@ -881,6 +881,10 @@ void __init early_trap_init(void *vectors_base) > > flush_icache_range(vectors, vectors + PAGE_SIZE * 2); > modify_domain(DOMAIN_USER, DOMAIN_CLIENT); > + > + /* Enable imprecise aborts */ > + local_abt_enable(); > + > #else /* ifndef CONFIG_CPU_V7M */ > /* > * on V7-M there is no need to copy the vector table to a > dedicated > -- 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/