From patchwork Tue Aug 26 10:03:16 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 4779361 Return-Path: X-Original-To: patchwork-linux-omap@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 D1555C0338 for ; Tue, 26 Aug 2014 10:04:10 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8A9E4201DE for ; Tue, 26 Aug 2014 10:04:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D83CD201DC for ; Tue, 26 Aug 2014 10:04:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934399AbaHZKDw (ORCPT ); Tue, 26 Aug 2014 06:03:52 -0400 Received: from fw-tnat.austin.arm.com ([217.140.110.23]:20515 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934266AbaHZKDt (ORCPT ); Tue, 26 Aug 2014 06:03:49 -0400 Received: from e102391-lin.cambridge.arm.com (e102391-lin.cambridge.arm.com [10.1.209.143]) by collaborate-mta1.arm.com (Postfix) with ESMTP id D04F113FA3E; Tue, 26 Aug 2014 05:03:45 -0500 (CDT) From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux@lists.openrisc.net Cc: linux@arm.linux.org.uk, shawn.guo@freescale.com, kernel@pengutronix.de, tony@atomide.com, catalin.marinas@arm.com, will.deacon@arm.com, jonas@southpole.se, tglx@linutronix.de, jason@lakedaemon.net, shc_work@mail.ru, baohua@kernel.org, maxime.ripard@free-electrons.com, marc.zyngier@arm.com, khilman@linaro.org, sboyd@codeaurora.org, lorenzo.pieralisi@arm.com, larry.bassel@linaro.org, mark.rutland@arm.com, sudeep.holla@arm.com, stefan.kristiansson@saunalahti.fi, vkale@apm.com, schwidefsky@de.ibm.com, Vladimir Murzin Subject: [PATCH v2 01/26] genirq: add irq_domain-aware core IRQ handler Date: Tue, 26 Aug 2014 11:03:16 +0100 Message-Id: <1409047421-27649-2-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 2.0.4 In-Reply-To: <1409047421-27649-1-git-send-email-marc.zyngier@arm.com> References: <1409047421-27649-1-git-send-email-marc.zyngier@arm.com> Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, 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 Calling irq_find_mapping from outside a irq_{enter,exit} section is unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled: If coming from the idle state, the rcu_read_lock call in irq_find_mapping will generate an unpleasant warning: =============================== [ INFO: suspicious RCU usage. ] 3.16.0-rc1+ #135 Not tainted ------------------------------- include/linux/rcupdate.h:871 rcu_read_lock() used illegally while idle! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0 RCU used illegally from extended quiescent state! 1 lock held by swapper/0/0: #0: (rcu_read_lock){......}, at: [] irq_find_mapping+0x4c/0x198 As this issue is fairly widespread and involves at least three different architectures, a possible solution is to add a new handle_domain_irq entry point into the generic IRQ code that the interrupt controller code can call. This new function takes an irq_domain, and calls into irq_find_domain inside the irq_{enter,exit} block. An additional "lookup" parameter is used to allow non-domain architecture code to be replaced by this as well. Interrupt controllers can then be updated to use the new mechanism. This code is sitting behind a new CONFIG_HANDLE_DOMAIN_IRQ, as not all architectures implement set_irq_regs (yes, mn10300, I'm looking at you...). Reported-by: Vladimir Murzin Signed-off-by: Marc Zyngier --- include/linux/irqdesc.h | 19 +++++++++++++++++++ kernel/irq/Kconfig | 3 +++ kernel/irq/irqdesc.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 64 insertions(+) diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index 472c021..ff24667 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -12,6 +12,8 @@ struct irq_affinity_notify; struct proc_dir_entry; struct module; struct irq_desc; +struct irq_domain; +struct pt_regs; /** * struct irq_desc - interrupt descriptor @@ -118,6 +120,23 @@ static inline void generic_handle_irq_desc(unsigned int irq, struct irq_desc *de int generic_handle_irq(unsigned int irq); +#ifdef CONFIG_HANDLE_DOMAIN_IRQ +/* + * Convert a HW interrupt number to a logical one using a IRQ domain, + * and handle the result interrupt number. Return -EINVAL if + * conversion failed. Providing a NULL domain indicates that the + * conversion has already been done. + */ +int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, + bool lookup, struct pt_regs *regs); + +static inline int handle_domain_irq(struct irq_domain *domain, + unsigned int hwirq, struct pt_regs *regs) +{ + return __handle_domain_irq(domain, hwirq, true, regs); +} +#endif + /* Test to see if a driver has successfully requested an irq */ static inline int irq_has_action(unsigned int irq) { diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index d269cec..225086b 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -55,6 +55,9 @@ config GENERIC_IRQ_CHIP config IRQ_DOMAIN bool +config HANDLE_DOMAIN_IRQ + bool + config IRQ_DOMAIN_DEBUG bool "Expose hardware/virtual IRQ mapping via debugfs" depends on IRQ_DOMAIN && DEBUG_FS diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 1487a12..a1782f8 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "internals.h" @@ -336,6 +337,47 @@ int generic_handle_irq(unsigned int irq) } EXPORT_SYMBOL_GPL(generic_handle_irq); +#ifdef CONFIG_HANDLE_DOMAIN_IRQ +/** + * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain + * @domain: The domain where to perform the lookup + * @hwirq: The HW irq number to convert to a logical one + * @lookup: Whether to perform the domain lookup or not + * @regs: Register file coming from the low-level handling code + * + * Returns: 0 on success, or -EINVAL if conversion has failed + */ +int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, + bool lookup, struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + unsigned int irq = hwirq; + int ret = 0; + + irq_enter(); + +#ifdef CONFIG_IRQ_DOMAIN + if (lookup) + irq = irq_find_mapping(domain, hwirq); +#endif + + /* + * Some hardware gives randomly wrong interrupts. Rather + * than crashing, do something sensible. + */ + if (unlikely(!irq || irq >= nr_irqs)) { + ack_bad_irq(irq); + ret = -EINVAL; + } else { + generic_handle_irq(irq); + } + + irq_exit(); + set_irq_regs(old_regs); + return ret; +} +#endif + /* Dynamic interrupt handling */ /**