From patchwork Mon Sep 1 14:21:37 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sudeep Holla X-Patchwork-Id: 4820041 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id AD21BC0338 for ; Mon, 1 Sep 2014 14:27:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EA444200E5 for ; Mon, 1 Sep 2014 14:26:55 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1A1F5200D6 for ; Mon, 1 Sep 2014 14:26:51 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XOSUT-0005Jt-79; Mon, 01 Sep 2014 14:21:53 +0000 Received: from fw-tnat.cambridge.arm.com ([217.140.96.21] helo=cam-smtp0.cambridge.arm.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XOSUM-0005DW-NF for linux-arm-kernel@lists.infradead.org; Mon, 01 Sep 2014 14:21:51 +0000 Received: from e103737-lin.cambridge.arm.com (e103737-lin.cambridge.arm.com [10.1.207.61]) by cam-smtp0.cambridge.arm.com (8.13.8/8.13.8) with ESMTP id s81EL2VI016654; Mon, 1 Sep 2014 15:21:02 +0100 From: Sudeep Holla To: ALKML Subject: [PATCH v2] arm: use irq_set_affinity with force=false when migrating irqs Date: Mon, 1 Sep 2014 15:21:37 +0100 Message-Id: <1409581297-29216-1-git-send-email-sudeep.holla@arm.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1409571966-18343-1-git-send-email-sudeep.holla@arm.com> References: <1409571966-18343-1-git-send-email-sudeep.holla@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140901_072147_117229_023D44F0 X-CRM114-Status: GOOD ( 13.09 ) X-Spam-Score: -4.0 (----) Cc: Mark Rutland , Thomas Gleixner , Russell King , stable@vger.kernel.org, Sudeep Holla X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-3.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Sudeep Holla Since commit 1dbfa187dad ("ARM: irq migration: force migration off CPU going down") the ARM interrupt migration code on cpu offline calls irqchip.irq_set_affinity() with the argument force=true. At the point of this change the argument had no effect because it was not used by any interrupt chip driver and there was no semantics defined. This changed with commit 01f8fa4f01d8 ("genirq: Allow forcing cpu affinity of interrupts") which made the force argument useful to route interrupts to not yet online cpus without checking the target cpu against the cpu online mask. The following commit ffde1de64012 ("irqchip: gic: Support forced affinity setting") implemented this for the GIC interrupt controller. As a consequence the ARM cpu offline irq migration fails if CPU0 is offlined, because CPU0 is still set in the affinity mask and the validataion against cpu online mask is skipped to the force argument being true. The following first_cpu(mask) selection always selects CPU0 as the target. Solve the issue by calling irq_set_affinity() with force=false from the CPU offline irq migration code so the GIC driver validates the affinity mask against CPU online mask and therefore removes CPU0 from the possible target candidates. Tested on TC2 hotpluging CPU0 in and out. Without this patch the system locks up as the IRQs are not migrated away from CPU0. Signed-off-by: Sudeep Holla Acked-by: Thomas Gleixner Cc: Russell King Cc: Mark Rutland Cc: # 3.10.x Acked-by: Mark Rutland --- arch/arm/kernel/irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Change v1->v2: - Updated the changelog to reflect the actual history behind this change as suggested by tglx and added his ack diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c index 2c4257604513..5c4d38e32a51 100644 --- a/arch/arm/kernel/irq.c +++ b/arch/arm/kernel/irq.c @@ -175,7 +175,7 @@ static bool migrate_one_irq(struct irq_desc *desc) c = irq_data_get_irq_chip(d); if (!c->irq_set_affinity) pr_debug("IRQ%u: unable to set affinity\n", d->irq); - else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret) + else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret) cpumask_copy(d->affinity, affinity); return ret;