From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guilherme G. Piccoli Date: Wed, 27 Apr 2022 19:48:56 -0300 Subject: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> Message-ID: <20220427224924.592546-3-gpiccoli@igalia.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org Currently the regular CPU shutdown path for ARM disables IRQs/FIQs in the secondary CPUs - smp_send_stop() calls ipi_cpu_stop(), which is responsible for that. This makes sense, since we're turning off such CPUs, putting them in an endless busy-wait loop. Problem is that there is an alternative path for disabling CPUs, in the form of function crash_smp_send_stop(), used for kexec/panic paths. This functions relies in a SMP call that also triggers a busy-wait loop [at machine_crash_nonpanic_core()], but *without* disabling interrupts. This might lead to odd scenarios, like early interrupts in the boot of kexec'd kernel or even interrupts in other CPUs while the main one still works in the panic path and assumes all secondary CPUs are (really!) off. This patch mimics the ipi_cpu_stop() interrupt disable mechanism in the crash CPU shutdown path, hence disabling IRQs/FIQs in all secondary CPUs in the kexec/panic path as well. Cc: Marc Zyngier Cc: Russell King Signed-off-by: Guilherme G. Piccoli --- arch/arm/kernel/machine_kexec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index f567032a09c0..ef788ee00519 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -86,6 +86,9 @@ void machine_crash_nonpanic_core(void *unused) set_cpu_online(smp_processor_id(), false); atomic_dec(&waiting_for_crash_ipi); + local_fiq_disable(); + local_irq_disable(); + while (1) { cpu_relax(); wfe(); -- 2.36.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Guilherme G. Piccoli" Subject: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Date: Wed, 27 Apr 2022 19:48:56 -0300 Message-ID: <20220427224924.592546-3-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3tSzLhxiCWvOXEBMYw5I07iytwEMkPfa6BAn8QO2Qvw=; b=s4B+SK+TdfUJ/x EFKYkA4yKJZIlZzFuSUreQIlpvHIDfbYylbYSLf0zidsXuhkcOnGApx2fdwnsIO+JIO/iYxXf4tCW 0hWoK4q8jlaJz46cgvzeavRHCzeYx0odW5kRGIGOHhADVFs7USp6j7L80P9wV/T+/gkhsP21s9JEi Is9E0QRDZ2IYumfD5kOYZp7a/bbjfLaUAv0NaExZj1jEIS5BJX6dlvTt5MeesE2b7+Cmu+aXqRpyu WPVFGpniv1qLtlAoOhYcGk2v8z/03oznzyte3LljpTIAApOj9IUoLbtDYIpXwfLDEb60GuEAxS8vZ cNcjyVW12H//aYXgXdwA==; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: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=9bJIN4/MOEhLx8CsVfKAquGTzb1mVDbHr+j6ymCNHAs=; b=S+EoVVMbG0R6l0pBfRnMsKZosp 2PXBHwhmghS5Lvs4v4GQMUSqpGyoQ5U6Zbnyj6sMhUP4BCGILxO7PkeMyVqV/H8eeh+l7ihT1MYQn 6lRWijWvq/MbBgY8W5xo5rf6VIJ8bQ3A6HUNn+RlRorsijlroe/vsascbDWK+dCTLeTv/edmbXzZt IkkQl7Ezob0EK5zEWLgIk+XPPHoVSiw2Ov7kaRBDa36NQrRgmO2O3HFxvBLZEYb5QzmHEcsWLMOdr YdjDzKF3as62X+/HBzxjW/bJqz3Ux15HOHGOCZtJDgeQcPUWNNi8PdpLZsxk0QJWHs39xjqIBwc58 XGSV7jaw==; In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+glud-user-mode-linux-devel=m.gmane-mx.org@lists.infradead.org To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, 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, gpiccoli@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. Currently the regular CPU shutdown path for ARM disables IRQs/FIQs in the secondary CPUs - smp_send_stop() calls ipi_cpu_stop(), which is responsible for that. This makes sense, since we're turning off such CPUs, putting them in an endless busy-wait loop. Problem is that there is an alternative path for disabling CPUs, in the form of function crash_smp_send_stop(), used for kexec/panic paths. This functions relies in a SMP call that also triggers a busy-wait loop [at machine_crash_nonpanic_core()], but *without* disabling interrupts. This might lead to odd scenarios, like early interrupts in the boot of kexec'd kernel or even interrupts in other CPUs while the main one still works in the panic path and assumes all secondary CPUs are (really!) off. This patch mimics the ipi_cpu_stop() interrupt disable mechanism in the crash CPU shutdown path, hence disabling IRQs/FIQs in all secondary CPUs in the kexec/panic path as well. Cc: Marc Zyngier Cc: Russell King Signed-off-by: Guilherme G. Piccoli --- arch/arm/kernel/machine_kexec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index f567032a09c0..ef788ee00519 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -86,6 +86,9 @@ void machine_crash_nonpanic_core(void *unused) set_cpu_online(smp_processor_id(), false); atomic_dec(&waiting_for_crash_ipi); + local_fiq_disable(); + local_irq_disable(); + while (1) { cpu_relax(); wfe(); -- 2.36.0 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 C3907C433F5 for ; Wed, 27 Apr 2022 22:52:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230508AbiD0Wzh (ORCPT ); Wed, 27 Apr 2022 18:55:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238241AbiD0Wxo (ORCPT ); Wed, 27 Apr 2022 18:53:44 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7757C8A305; Wed, 27 Apr 2022 15:50:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: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=9bJIN4/MOEhLx8CsVfKAquGTzb1mVDbHr+j6ymCNHAs=; b=S+EoVVMbG0R6l0pBfRnMsKZosp 2PXBHwhmghS5Lvs4v4GQMUSqpGyoQ5U6Zbnyj6sMhUP4BCGILxO7PkeMyVqV/H8eeh+l7ihT1MYQn 6lRWijWvq/MbBgY8W5xo5rf6VIJ8bQ3A6HUNn+RlRorsijlroe/vsascbDWK+dCTLeTv/edmbXzZt IkkQl7Ezob0EK5zEWLgIk+XPPHoVSiw2Ov7kaRBDa36NQrRgmO2O3HFxvBLZEYb5QzmHEcsWLMOdr YdjDzKF3as62X+/HBzxjW/bJqz3Ux15HOHGOCZtJDgeQcPUWNNi8PdpLZsxk0QJWHs39xjqIBwc58 XGSV7jaw==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqU9-0001ye-3z; Thu, 28 Apr 2022 00:50:14 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, 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, gpiccoli@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, mikelley@microsoft.com, 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, Marc Zyngier , Russell King Subject: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Date: Wed, 27 Apr 2022 19:48:56 -0300 Message-Id: <20220427224924.592546-3-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org Currently the regular CPU shutdown path for ARM disables IRQs/FIQs in the secondary CPUs - smp_send_stop() calls ipi_cpu_stop(), which is responsible for that. This makes sense, since we're turning off such CPUs, putting them in an endless busy-wait loop. Problem is that there is an alternative path for disabling CPUs, in the form of function crash_smp_send_stop(), used for kexec/panic paths. This functions relies in a SMP call that also triggers a busy-wait loop [at machine_crash_nonpanic_core()], but *without* disabling interrupts. This might lead to odd scenarios, like early interrupts in the boot of kexec'd kernel or even interrupts in other CPUs while the main one still works in the panic path and assumes all secondary CPUs are (really!) off. This patch mimics the ipi_cpu_stop() interrupt disable mechanism in the crash CPU shutdown path, hence disabling IRQs/FIQs in all secondary CPUs in the kexec/panic path as well. Cc: Marc Zyngier Cc: Russell King Signed-off-by: Guilherme G. Piccoli --- arch/arm/kernel/machine_kexec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index f567032a09c0..ef788ee00519 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -86,6 +86,9 @@ void machine_crash_nonpanic_core(void *unused) set_cpu_online(smp_processor_id(), false); atomic_dec(&waiting_for_crash_ipi); + local_fiq_disable(); + local_irq_disable(); + while (1) { cpu_relax(); wfe(); -- 2.36.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: "Guilherme G. Piccoli" Subject: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Date: Wed, 27 Apr 2022 19:48:56 -0300 Message-Id: <20220427224924.592546-3-gpiccoli@igalia.com> In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 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: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, 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, gpiccoli@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, mikelley@microsoft.com, 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, Marc Zyngier , Russell King Currently the regular CPU shutdown path for ARM disables IRQs/FIQs in the secondary CPUs - smp_send_stop() calls ipi_cpu_stop(), which is responsible for that. This makes sense, since we're turning off such CPUs, putting them in an endless busy-wait loop. Problem is that there is an alternative path for disabling CPUs, in the form of function crash_smp_send_stop(), used for kexec/panic paths. This functions relies in a SMP call that also triggers a busy-wait loop [at machine_crash_nonpanic_core()], but *without* disabling interrupts. This might lead to odd scenarios, like early interrupts in the boot of kexec'd kernel or even interrupts in other CPUs while the main one still works in the panic path and assumes all secondary CPUs are (really!) off. This patch mimics the ipi_cpu_stop() interrupt disable mechanism in the crash CPU shutdown path, hence disabling IRQs/FIQs in all secondary CPUs in the kexec/panic path as well. Cc: Marc Zyngier Cc: Russell King Signed-off-by: Guilherme G. Piccoli --- arch/arm/kernel/machine_kexec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index f567032a09c0..ef788ee00519 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -86,6 +86,9 @@ void machine_crash_nonpanic_core(void *unused) set_cpu_online(smp_processor_id(), false); atomic_dec(&waiting_for_crash_ipi); + local_fiq_disable(); + local_irq_disable(); + while (1) { cpu_relax(); wfe(); -- 2.36.0 _______________________________________________ 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 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 E2FF9C433EF for ; Thu, 28 Apr 2022 01:50:02 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Kpdpx4FWJz3fmq for ; Thu, 28 Apr 2022 11:50:01 +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=S+EoVVMb; 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=S+EoVVMb; 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 4KpZZX5tj5z3bbV for ; Thu, 28 Apr 2022 09:24:04 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: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=9bJIN4/MOEhLx8CsVfKAquGTzb1mVDbHr+j6ymCNHAs=; b=S+EoVVMbG0R6l0pBfRnMsKZosp 2PXBHwhmghS5Lvs4v4GQMUSqpGyoQ5U6Zbnyj6sMhUP4BCGILxO7PkeMyVqV/H8eeh+l7ihT1MYQn 6lRWijWvq/MbBgY8W5xo5rf6VIJ8bQ3A6HUNn+RlRorsijlroe/vsascbDWK+dCTLeTv/edmbXzZt IkkQl7Ezob0EK5zEWLgIk+XPPHoVSiw2Ov7kaRBDa36NQrRgmO2O3HFxvBLZEYb5QzmHEcsWLMOdr YdjDzKF3as62X+/HBzxjW/bJqz3Ux15HOHGOCZtJDgeQcPUWNNi8PdpLZsxk0QJWHs39xjqIBwc58 XGSV7jaw==; Received: from [179.113.53.197] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1njqU9-0001ye-3z; Thu, 28 Apr 2022 00:50:14 +0200 From: "Guilherme G. Piccoli" To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Subject: [PATCH 02/30] ARM: kexec: Disable IRQs/FIQs also on crash CPUs shutdown path Date: Wed, 27 Apr 2022 19:48:56 -0300 Message-Id: <20220427224924.592546-3-gpiccoli@igalia.com> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Thu, 28 Apr 2022 11:34:03 +1000 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, gregkh@linuxfoundation.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, mikelley@microsoft.com, john.ogness@linutronix.de, 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, linux-xtensa@linux-xtensa.org, dave.hansen@linux.intel.com, keescook@chromium.org, arnd@arndb.de, linux-pm@vger.kernel.org, coresight@lists.linaro.org, linux-um@lists.infradead.org, rostedt@goodmis.org, rcu@vger.kernel.org, bp@alien8.de, luto@kernel.org, linux-tegra@vger.kernel.org, Marc Zyngier , openipmi-developer@lists.sourceforge.net, andriy.shevchenko@linux.intel.com, senozhatsky@chromium.org, 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, linux-kernel@vger.kernel.org, stern@rowland.harvard.edu, gpiccoli@igalia.com, d.hatayama@jp.fujitsu.com, mhiramat@kernel.org, kernel-dev@igalia.com, linux-alpha@vger.kernel.org, vkuznets@redhat.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Currently the regular CPU shutdown path for ARM disables IRQs/FIQs in the secondary CPUs - smp_send_stop() calls ipi_cpu_stop(), which is responsible for that. This makes sense, since we're turning off such CPUs, putting them in an endless busy-wait loop. Problem is that there is an alternative path for disabling CPUs, in the form of function crash_smp_send_stop(), used for kexec/panic paths. This functions relies in a SMP call that also triggers a busy-wait loop [at machine_crash_nonpanic_core()], but *without* disabling interrupts. This might lead to odd scenarios, like early interrupts in the boot of kexec'd kernel or even interrupts in other CPUs while the main one still works in the panic path and assumes all secondary CPUs are (really!) off. This patch mimics the ipi_cpu_stop() interrupt disable mechanism in the crash CPU shutdown path, hence disabling IRQs/FIQs in all secondary CPUs in the kexec/panic path as well. Cc: Marc Zyngier Cc: Russell King Signed-off-by: Guilherme G. Piccoli --- arch/arm/kernel/machine_kexec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index f567032a09c0..ef788ee00519 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -86,6 +86,9 @@ void machine_crash_nonpanic_core(void *unused) set_cpu_online(smp_processor_id(), false); atomic_dec(&waiting_for_crash_ipi); + local_fiq_disable(); + local_irq_disable(); + while (1) { cpu_relax(); wfe(); -- 2.36.0