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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8E43C43332 for ; Mon, 15 Mar 2021 11:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AAB1D64EF3 for ; Mon, 15 Mar 2021 11:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230394AbhCOL4w (ORCPT ); Mon, 15 Mar 2021 07:56:52 -0400 Received: from foss.arm.com ([217.140.110.172]:35068 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229921AbhCOL4o (ORCPT ); Mon, 15 Mar 2021 07:56:44 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0156611D4; Mon, 15 Mar 2021 04:56:44 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BEEC33F792; Mon, 15 Mar 2021 04:56:42 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com Cc: james.morse@arm.com, marcan@marcan.st, mark.rutland@arm.com, maz@kernel.org, tglx@linutronix.de Subject: [PATCHv3 3/6] arm64: irq: rework root IRQ handler registration Date: Mon, 15 Mar 2021 11:56:26 +0000 Message-Id: <20210315115629.57191-4-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20210315115629.57191-1-mark.rutland@arm.com> References: <20210315115629.57191-1-mark.rutland@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we accidentally unmask IRQs before we've registered a root IRQ handler, handle_arch_irq will be NULL, and the IRQ exception handler will branch to a bogus address. To make this easier to debug, this patch initialises handle_arch_irq to a default handler which will panic(), making such problems easier to debug. When we add support for FIQ handlers, we can follow the same approach. When we add support for a root FIQ handler, it's possible to have root IRQ handler without an root FIQ handler, and in theory the inverse is also possible. To permit this, and to keep the IRQ/FIQ registration logic similar, this patch removes the panic in the absence of a root IRQ controller. Instead, set_handle_irq() logs when a handler is registered, which is sufficient for debug purposes. Signed-off-by: Mark Rutland Tested-by: Hector Martin Cc: Catalin Marinas Cc: James Morse Cc: Marc Zyngier Cc: Thomas Gleixner Cc: Will Deacon --- arch/arm64/kernel/irq.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c index ad63bd50fa7b..2fe0b535de30 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -71,14 +71,20 @@ static void init_irq_stacks(void) } #endif -void (*handle_arch_irq)(struct pt_regs *) __ro_after_init; +static void default_handle_irq(struct pt_regs *regs) +{ + panic("IRQ taken without a root IRQ handler\n"); +} + +void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq; int __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) { - if (handle_arch_irq) + if (handle_arch_irq != default_handle_irq) return -EBUSY; handle_arch_irq = handle_irq; + pr_info("Root IRQ handler: %ps\n", handle_irq); return 0; } @@ -87,8 +93,6 @@ void __init init_IRQ(void) init_irq_stacks(); init_irq_scs(); irqchip_init(); - if (!handle_arch_irq) - panic("No interrupt controller found."); if (system_uses_irq_prio_masking()) { /* -- 2.11.0