Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754701AbbGPJNa (ORCPT ); Thu, 16 Jul 2015 05:13:30 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:37004 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753892AbbGPJN2 (ORCPT ); Thu, 16 Jul 2015 05:13:28 -0400 Subject: Re: [PATCH 3/3] ARM: add basic support for on-demand backtrace of other CPUs To: Russell King , linux-arm-kernel@lists.infradead.org, x86@kernel.org References: <20150715203911.GF7557@n2100.arm.linux.org.uk> Cc: linux-kernel@vger.kernel.org From: Daniel Thompson Message-ID: <55A775B6.8080505@linaro.org> Date: Thu, 16 Jul 2015 10:13:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 MIME-Version: 1.0 In-Reply-To: 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: 1517 Lines: 38 On 15/07/15 21:39, Russell King wrote: > As we now have generic infrastructure to support backtracing of other > CPUs in the system on lockups, we can start to implement this for ARM. > Initially, we add an IPI based implementation, as the GIC code needs > modification to support the generation of FIQ IPIs, and not all ARM > platforms have the ability to raise a FIQ in the non-secure world. > > This provides us with a "best efforts" implementation in the absence > of FIQs. > > Signed-off-by: Russell King > --- > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > index 90dfbedfbfb8..3a20c386fd33 100644 > --- a/arch/arm/kernel/smp.c > +++ b/arch/arm/kernel/smp.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -72,6 +73,7 @@ enum ipi_msg_type { > IPI_CPU_STOP, > IPI_IRQ_WORK, > IPI_COMPLETION, > + IPI_CPU_BACKTRACE = 15, Even with the potential for (eventually) being signalled by FIQ, is this IPI really so special it needs to be placed outside the scope of NR_IPI and the accounting and tracing support it brings with it? -- 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/