From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35C4CC4321E for ; Fri, 29 Apr 2022 21:39:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237894AbiD2Vme (ORCPT ); Fri, 29 Apr 2022 17:42:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232254AbiD2Vmc (ORCPT ); Fri, 29 Apr 2022 17:42:32 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B4AFABF6F; Fri, 29 Apr 2022 14:39:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=zaZR6AionffdB1xNnJGX+2SLzxIRGHxmDTzkdAsF8Lw=; b=f2se15ohqCxFdZ9Cbwp90MFGzT jTOap9gxEPPT4aTyNt5E3ZHiiiT+V3lzyiVXivZvxSS+ElUToKTRjGns0j7W5gu+rUZwjHaY5hGeN otkXyAwqu6HD3avUoXVIxjGs+UlKUlBOe/StJroDKFugT/kZL7npThsCdsHpDWufEk+wh4fOOIDQw l7OyKb0Jm89RaQG7TSk5bTRs2tlRpACA1IvBqK2eiZLAu6g1+MyYc/cQwPm5SUuYLGV0bPXJdES3s lnyV4bPi3phdA0er49wiR1R3K1IMQcdtRi5k8Pou9s9nypOSId//IHiPuzLjmzkdZNlZyJjIhfVzV toxHByUQ==; Received: from [179.113.53.197] (helo=[192.168.1.60]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1nkYK9-0001bD-CM; Fri, 29 Apr 2022 23:38:49 +0200 Message-ID: <71d829c4-b280-7d6e-647d-79a1baf9408b@igalia.com> Date: Fri, 29 Apr 2022 18:38:19 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Content-Language: en-US To: Marc Zyngier , "Michael Kelley (LINUX)" Cc: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Russell King References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-3-gpiccoli@igalia.com> <87mtg392fm.wl-maz@kernel.org> From: "Guilherme G. Piccoli" In-Reply-To: <87mtg392fm.wl-maz@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org Thanks Marc and Michael for the review/discussion. On 29/04/2022 15:20, Marc Zyngier wrote: > [...] > My expectations would be that, since we're getting here using an IPI, > interrupts are already masked. So what reenabled them the first place? > > Thanks, > > M. > Marc, I did some investigation in the code (and tried/failed in the ARM documentation as well heh), but this is still not 100% clear for me. You're saying IPI calls disable IRQs/FIQs by default in the the target CPUs? Where does it happen? I'm a bit confused if this a processor mechanism, or it's in code. Looking the smp_send_stop() in arch/arm/, it does IPI the CPUs, with the flag IPI_CPU_STOP, eventually calling ipi_cpu_stop(), and the latter does disable IRQ/FIQ in code - that's where I stole my code from. But crash_smp_send_stop() is different, it seems to IPI the other CPUs with the flag IPI_CALL_FUNC, which leads to calling generic_smp_call_function_interrupt() - does it disable interrupts/FIQs as well? I couldn't find it. Appreciate your clarifications about that, thanks again. Cheers, Guilherme From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EC279C433EF for ; Fri, 29 Apr 2022 21:40:01 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Kqm9X1mrnz3bwb for ; Sat, 30 Apr 2022 07:40:00 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=f2se15oh; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=igalia.com (client-ip=178.60.130.6; helo=fanzine2.igalia.com; envelope-from=gpiccoli@igalia.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=f2se15oh; dkim-atps=neutral Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Kqm8m1X15z3bZs for ; Sat, 30 Apr 2022 07:39:17 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=zaZR6AionffdB1xNnJGX+2SLzxIRGHxmDTzkdAsF8Lw=; b=f2se15ohqCxFdZ9Cbwp90MFGzT jTOap9gxEPPT4aTyNt5E3ZHiiiT+V3lzyiVXivZvxSS+ElUToKTRjGns0j7W5gu+rUZwjHaY5hGeN otkXyAwqu6HD3avUoXVIxjGs+UlKUlBOe/StJroDKFugT/kZL7npThsCdsHpDWufEk+wh4fOOIDQw l7OyKb0Jm89RaQG7TSk5bTRs2tlRpACA1IvBqK2eiZLAu6g1+MyYc/cQwPm5SUuYLGV0bPXJdES3s lnyV4bPi3phdA0er49wiR1R3K1IMQcdtRi5k8Pou9s9nypOSId//IHiPuzLjmzkdZNlZyJjIhfVzV toxHByUQ==; Received: from [179.113.53.197] (helo=[192.168.1.60]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1nkYK9-0001bD-CM; Fri, 29 Apr 2022 23:38:49 +0200 Message-ID: <71d829c4-b280-7d6e-647d-79a1baf9408b@igalia.com> Date: Fri, 29 Apr 2022 18:38:19 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Content-Language: en-US To: Marc Zyngier , "Michael Kelley (LINUX)" References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-3-gpiccoli@igalia.com> <87mtg392fm.wl-maz@kernel.org> From: "Guilherme G. Piccoli" In-Reply-To: <87mtg392fm.wl-maz@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-hyperv@vger.kernel.org, halves@canonical.com, linux-xtensa@linux-xtensa.org, peterz@infradead.org, alejandro.j.jimenez@oracle.com, linux-remoteproc@vger.kernel.org, feng.tang@intel.com, linux-mips@vger.kernel.org, hidehiro.kawai.ez@hitachi.com, sparclinux@vger.kernel.org, will@kernel.org, tglx@linutronix.de, linux-leds@vger.kernel.org, linux-s390@vger.kernel.org, john.ogness@linutronix.de, bhe@redhat.com, corbet@lwn.net, paulmck@kernel.org, fabiomirmar@gmail.com, x86@kernel.org, Russell King , mingo@redhat.com, bcm-kernel-feedback-list@broadcom.com, xen-devel@lists.xenproject.org, dyoung@redhat.com, vgoyal@redhat.com, pmladek@suse.com, dave.hansen@linux.intel.com, keescook@chromium.org, arnd@arndb.de, linux-pm@vger.kernel.org, linux-um@lists.infradead.org, rostedt@goodmis.org, rcu@vger.kernel.org, gregkh@linuxfoundation.org, bp@alien8.de, luto@kernel.org, linux-tegra@vger.kernel.org, openipmi-developer@lists.sourceforge.net, andriy.shevchenko@linux.intel.com, vkuznets@redhat.com, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, jgross@suse.com, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, kernel@gpiccoli.net, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, stern@rowland.harvard.edu, senozhatsky@chromium.org, d.hatayama@jp.fujitsu.com, mhiramat@kernel.org, kernel-dev@igalia.com, linux-alpha@vger.kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Thanks Marc and Michael for the review/discussion. On 29/04/2022 15:20, Marc Zyngier wrote: > [...] > My expectations would be that, since we're getting here using an IPI, > interrupts are already masked. So what reenabled them the first place? > > Thanks, > > M. > Marc, I did some investigation in the code (and tried/failed in the ARM documentation as well heh), but this is still not 100% clear for me. You're saying IPI calls disable IRQs/FIQs by default in the the target CPUs? Where does it happen? I'm a bit confused if this a processor mechanism, or it's in code. Looking the smp_send_stop() in arch/arm/, it does IPI the CPUs, with the flag IPI_CPU_STOP, eventually calling ipi_cpu_stop(), and the latter does disable IRQ/FIQ in code - that's where I stole my code from. But crash_smp_send_stop() is different, it seems to IPI the other CPUs with the flag IPI_CALL_FUNC, which leads to calling generic_smp_call_function_interrupt() - does it disable interrupts/FIQs as well? I couldn't find it. Appreciate your clarifications about that, thanks again. Cheers, Guilherme From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guilherme G. Piccoli Date: Fri, 29 Apr 2022 18:38:19 -0300 Subject: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path In-Reply-To: <87mtg392fm.wl-maz@kernel.org> References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-3-gpiccoli@igalia.com> <87mtg392fm.wl-maz@kernel.org> Message-ID: <71d829c4-b280-7d6e-647d-79a1baf9408b@igalia.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org Thanks Marc and Michael for the review/discussion. On 29/04/2022 15:20, Marc Zyngier wrote: > [...] > My expectations would be that, since we're getting here using an IPI, > interrupts are already masked. So what reenabled them the first place? > > Thanks, > > M. > Marc, I did some investigation in the code (and tried/failed in the ARM documentation as well heh), but this is still not 100% clear for me. You're saying IPI calls disable IRQs/FIQs by default in the the target CPUs? Where does it happen? I'm a bit confused if this a processor mechanism, or it's in code. Looking the smp_send_stop() in arch/arm/, it does IPI the CPUs, with the flag IPI_CPU_STOP, eventually calling ipi_cpu_stop(), and the latter does disable IRQ/FIQ in code - that's where I stole my code from. But crash_smp_send_stop() is different, it seems to IPI the other CPUs with the flag IPI_CALL_FUNC, which leads to calling generic_smp_call_function_interrupt() - does it disable interrupts/FIQs as well? I couldn't find it. Appreciate your clarifications about that, thanks again. Cheers, Guilherme From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <71d829c4-b280-7d6e-647d-79a1baf9408b@igalia.com> Date: Fri, 29 Apr 2022 18:38:19 -0300 MIME-Version: 1.0 Subject: Re: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Content-Language: en-US References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-3-gpiccoli@igalia.com> <87mtg392fm.wl-maz@kernel.org> From: "Guilherme G. Piccoli" In-Reply-To: <87mtg392fm.wl-maz@kernel.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Marc Zyngier , "Michael Kelley (LINUX)" Cc: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org, Russell King Thanks Marc and Michael for the review/discussion. On 29/04/2022 15:20, Marc Zyngier wrote: > [...] > My expectations would be that, since we're getting here using an IPI, > interrupts are already masked. So what reenabled them the first place? > > Thanks, > > M. > Marc, I did some investigation in the code (and tried/failed in the ARM documentation as well heh), but this is still not 100% clear for me. You're saying IPI calls disable IRQs/FIQs by default in the the target CPUs? Where does it happen? I'm a bit confused if this a processor mechanism, or it's in code. Looking the smp_send_stop() in arch/arm/, it does IPI the CPUs, with the flag IPI_CPU_STOP, eventually calling ipi_cpu_stop(), and the latter does disable IRQ/FIQ in code - that's where I stole my code from. But crash_smp_send_stop() is different, it seems to IPI the other CPUs with the flag IPI_CALL_FUNC, which leads to calling generic_smp_call_function_interrupt() - does it disable interrupts/FIQs as well? I couldn't find it. Appreciate your clarifications about that, thanks again. Cheers, Guilherme _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Guilherme G. Piccoli" Subject: Re: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Date: Fri, 29 Apr 2022 18:38:19 -0300 Message-ID: <71d829c4-b280-7d6e-647d-79a1baf9408b@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-3-gpiccoli@igalia.com> <87mtg392fm.wl-maz@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=zaZR6AionffdB1xNnJGX+2SLzxIRGHxmDTzkdAsF8Lw=; b=f2se15ohqCxFdZ9Cbwp90MFGzT jTOap9gxEPPT4aTyNt5E3ZHiiiT+V3lzyiVXivZvxSS+ElUToKTRjGns0j7W5gu+rUZwjHaY5hGeN otkXyAwqu6HD3avUoXVIxjGs+UlKUlBOe/StJroDKFugT/kZL7npThsCdsHpDWufEk+wh4fOOIDQw l7OyKb0Jm89RaQG7TSk5bTRs2tlRpACA1IvBqK2eiZLAu6g1+MyYc/cQwPm5SUuYLGV0bPXJdES3s lnyV4bPi3phdA0er49wiR1R3K1IMQcdtRi5k8Pou9s9nypOSId//IHiPuzLjmzkdZNlZyJjIhfVzV toxHByU Content-Language: en-US In-Reply-To: <87mtg392fm.wl-maz-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" To: Marc Zyngier , "Michael Kelley (LINUX)" Cc: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, pmladek-IBi9RG/b67k@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, bcm-kernel-feedback-list-dY08KVG/lbpWk0Htik3J/w@public.gmane.org, linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-alpha-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-edac-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-hyperv-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-leds-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mips-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-parisc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-remoteproc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-s390-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-um-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-xtensa-PjhNF2WwrV/0Sa2dR60CXw@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, openipmi-developer-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, rcu-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, xen-devel-GuqFBffKawtpuQazS67q72D2FQJk+8+b@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, kernel-dev-wEGTBA9jqPzQT0dZR+AlfA@public.gmane.org, kernel-WeLdAqEWwDvk1uMJSBkQmQ@public.gmane.org, halves@c Thanks Marc and Michael for the review/discussion. On 29/04/2022 15:20, Marc Zyngier wrote: > [...] > My expectations would be that, since we're getting here using an IPI, > interrupts are already masked. So what reenabled them the first place? > > Thanks, > > M. > Marc, I did some investigation in the code (and tried/failed in the ARM documentation as well heh), but this is still not 100% clear for me. You're saying IPI calls disable IRQs/FIQs by default in the the target CPUs? Where does it happen? I'm a bit confused if this a processor mechanism, or it's in code. Looking the smp_send_stop() in arch/arm/, it does IPI the CPUs, with the flag IPI_CPU_STOP, eventually calling ipi_cpu_stop(), and the latter does disable IRQ/FIQ in code - that's where I stole my code from. But crash_smp_send_stop() is different, it seems to IPI the other CPUs with the flag IPI_CALL_FUNC, which leads to calling generic_smp_call_function_interrupt() - does it disable interrupts/FIQs as well? I couldn't find it. Appreciate your clarifications about that, thanks again. Cheers, Guilherme