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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604236480; bh=0Q0TyWyxmTzOkgODkUAvpvR4auOZp81vUdIbLC17N/Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ofP7EqQnjQbpnpvjaL47h852YemIWNClTuCh67g1BlfRqaiq+GRqOzo9xBXAxRs5J A0Ty3JMFDk5Qnj8NrFAKcXsLz/aqHm7rCLyUXCfiuj/cfZbCwQkLI+nJuk3HZXyEk4 Tmw/i1gonbWtGqjktdanhMLHb7vfMhLTc6WcL0OQ= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1kZDBu-006QYT-QK; Sun, 01 Nov 2020 13:14:38 +0000 From: Marc Zyngier To: LAK , linux-kernel Subject: [PATCH 1/2] genirq: Allow an interrupt to be marked as 'naked' Date: Sun, 1 Nov 2020 13:14:29 +0000 Message-Id: <20201101131430.257038-2-maz@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201101131430.257038-1-maz@kernel.org> References: <20201101131430.257038-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, tglx@linutronix.de, Valentin.Schneider@arm.com, peterz@infradead.org, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201101_081441_448342_8638923F X-CRM114-Status: GOOD ( 20.98 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Will Deacon , Peter Zijlstra , Catalin Marinas , Thomas Gleixner , Android Kernel Team , Valentin Schneider Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Some interrupts (such as the rescheduling IPI) rely on not going through the irq_enter()/irq_exit() calls. To distinguish such interrupts, add a new IRQ flag that allows the low-level handling code to sidestep the enter()/exit() calls. Only the architecture code is expected to use this. It will do the wrong thing on normal interrupts. Signed-off-by: Marc Zyngier --- include/linux/irq.h | 4 +++- kernel/irq/debugfs.c | 1 + kernel/irq/irqdesc.c | 17 ++++++++++++----- kernel/irq/settings.h | 7 +++++++ 4 files changed, 23 insertions(+), 6 deletions(-) diff --git a/include/linux/irq.h b/include/linux/irq.h index c54365309e97..af5ba7336925 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -72,6 +72,7 @@ enum irqchip_irq_state; * mechanism and from core side polling. * IRQ_DISABLE_UNLAZY - Disable lazy irq disable * IRQ_HIDDEN - Don't show up in /proc/interrupts + * IRQ_NAKED - Bypass irq_enter()/irq_exit() */ enum { IRQ_TYPE_NONE = 0x00000000, @@ -99,13 +100,14 @@ enum { IRQ_IS_POLLED = (1 << 18), IRQ_DISABLE_UNLAZY = (1 << 19), IRQ_HIDDEN = (1 << 20), + IRQ_NAKED = (1 << 21), }; #define IRQF_MODIFY_MASK \ (IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \ IRQ_NOAUTOEN | IRQ_MOVE_PCNTXT | IRQ_LEVEL | IRQ_NO_BALANCING | \ IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID | \ - IRQ_IS_POLLED | IRQ_DISABLE_UNLAZY | IRQ_HIDDEN) + IRQ_IS_POLLED | IRQ_DISABLE_UNLAZY | IRQ_HIDDEN | IRQ_NAKED) #define IRQ_NO_BALANCING_MASK (IRQ_PER_CPU | IRQ_NO_BALANCING) diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c index e4cff358b437..e031d6afc0f8 100644 --- a/kernel/irq/debugfs.c +++ b/kernel/irq/debugfs.c @@ -140,6 +140,7 @@ static const struct irq_bit_descr irqdesc_states[] = { BIT_MASK_DESCR(_IRQ_IS_POLLED), BIT_MASK_DESCR(_IRQ_DISABLE_UNLAZY), BIT_MASK_DESCR(_IRQ_HIDDEN), + BIT_MASK_DESCR(_IRQ_NAKED), }; static const struct irq_bit_descr irqdesc_istates[] = { diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 1a7723604399..c08a1c19d061 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -667,10 +667,9 @@ int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, { struct pt_regs *old_regs = set_irq_regs(regs); unsigned int irq = hwirq; + struct irq_desc *desc; int ret = 0; - irq_enter(); - #ifdef CONFIG_IRQ_DOMAIN if (lookup) irq = irq_find_mapping(domain, hwirq); @@ -680,14 +679,22 @@ int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq, * Some hardware gives randomly wrong interrupts. Rather * than crashing, do something sensible. */ - if (unlikely(!irq || irq >= nr_irqs)) { + desc = irq_to_desc(irq); + if (unlikely(!desc || irq >= nr_irqs)) { ack_bad_irq(irq); ret = -EINVAL; + goto out; + } + + if (unlikely(irq_settings_is_naked(desc))) { + generic_handle_irq_desc(desc); } else { - generic_handle_irq(irq); + irq_enter(); + generic_handle_irq_desc(desc); + irq_exit(); } - irq_exit(); +out: set_irq_regs(old_regs); return ret; } diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h index 403378b9947b..587e67f9c302 100644 --- a/kernel/irq/settings.h +++ b/kernel/irq/settings.h @@ -18,6 +18,7 @@ enum { _IRQ_IS_POLLED = IRQ_IS_POLLED, _IRQ_DISABLE_UNLAZY = IRQ_DISABLE_UNLAZY, _IRQ_HIDDEN = IRQ_HIDDEN, + _IRQ_NAKED = IRQ_NAKED, _IRQF_MODIFY_MASK = IRQF_MODIFY_MASK, }; @@ -33,6 +34,7 @@ enum { #define IRQ_IS_POLLED GOT_YOU_MORON #define IRQ_DISABLE_UNLAZY GOT_YOU_MORON #define IRQ_HIDDEN GOT_YOU_MORON +#define IRQ_NAKED GOT_YOU_MORON #undef IRQF_MODIFY_MASK #define IRQF_MODIFY_MASK GOT_YOU_MORON @@ -174,3 +176,8 @@ static inline bool irq_settings_is_hidden(struct irq_desc *desc) { return desc->status_use_accessors & _IRQ_HIDDEN; } + +static inline bool irq_settings_is_naked(struct irq_desc *desc) +{ + return desc->status_use_accessors & _IRQ_NAKED; +}