Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754795AbbHQOJ7 (ORCPT ); Mon, 17 Aug 2015 10:09:59 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:35762 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750975AbbHQOJ6 (ORCPT ); Mon, 17 Aug 2015 10:09:58 -0400 Message-ID: <55D1EB0B.8020607@ti.com> Date: Mon, 17 Aug 2015 10:09:15 -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: Russell King - ARM Linux CC: Lucas Stach , , , 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> <55CE63BD.2060107@ti.com> <20150814215658.GB7557@n2100.arm.linux.org.uk> In-Reply-To: <20150814215658.GB7557@n2100.arm.linux.org.uk> 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: 4668 Lines: 143 On 08/14/2015 05:56 PM, Russell King - ARM Linux wrote: > On Fri, Aug 14, 2015 at 05:55:09PM -0400, Murali Karicheri wrote: >> 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. > > If you look below, Lucas provided the patch. Oops! Thanks Murali > >> >> 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 > -- 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/