Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753457AbbHNV5I (ORCPT ); Fri, 14 Aug 2015 17:57:08 -0400 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:60229 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752549AbbHNV5G (ORCPT ); Fri, 14 Aug 2015 17:57:06 -0400 Date: Fri, 14 Aug 2015 22:56:58 +0100 From: Russell King - ARM Linux To: Murali Karicheri Cc: Lucas Stach , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ssantosh@kernel.org Subject: Re: [PATCH] ARM: keystone: add a work around to handle asynchronous external abort Message-ID: <20150814215658.GB7557@n2100.arm.linux.org.uk> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55CE63BD.2060107@ti.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4543 Lines: 136 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. > > 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 -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- 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/