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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 1EF67C4332B for ; Tue, 2 Mar 2021 10:39:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF24264F0A for ; Tue, 2 Mar 2021 10:39:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1578057AbhCBKfT (ORCPT ); Tue, 2 Mar 2021 05:35:19 -0500 Received: from foss.arm.com ([217.140.110.172]:48358 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1382775AbhCBKP3 (ORCPT ); Tue, 2 Mar 2021 05:15:29 -0500 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 D338513A1; Tue, 2 Mar 2021 02:12:31 -0800 (PST) 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 9BDA33F70D; Tue, 2 Mar 2021 02:12:30 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: catalin.marinas@arm.com, james.morse@arm.com, marcan@marcan.st, mark.rutland@arm.com, maz@kernel.org, tglx@linutronix.de, will@kernel.org Subject: [PATCHv2 5/8] arm64: irq: rework root IRQ handler registration Date: Tue, 2 Mar 2021 10:12:08 +0000 Message-Id: <20210302101211.2328-6-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20210302101211.2328-1-mark.rutland@arm.com> References: <20210302101211.2328-1-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 Cc: Catalin Marinas Cc: Hector Martin 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