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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C4476C433EF for ; Fri, 4 Feb 2022 15:08:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=9m6oL/6ZSeOhAMivKyD6IlDIeI+s6SgVcsBT/MeK8U8=; b=z0O5r+U5BbZIWf N5Rpp4g225pkat7wLQgXfsz14qeGiEGAtKdgKFrO0al0mW52pBUGNoiTPK9LTHwfISDvzR78Pg5m5 aOmX4bLCW759hWXN0DX/ThExTKn/GNjXCYr9i0riAH/kvqtDjPskPt8c1FLT/N7gKWZdpAaE6Wj8Y GQD23Z8YrmJ6IPOhcOD6jMCUCy58z1chbcj1HcrXs0LEwAtqe2AlJSqeBsu4YOXhbK19A9XLaI1TL 0B1BsSBVVjNUMevbeBRi/JyULKZq5T3M8ZtK2pUul5k2yX82/skU8MFPKeb4pTc7DK8Pk+B6ximpZ 36ttaVJ2Z7nNU5RNe25A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nG0B8-004exO-U0; Fri, 04 Feb 2022 15:07:15 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nG0AN-004efP-5U for linux-arm-kernel@lists.infradead.org; Fri, 04 Feb 2022 15:06:28 +0000 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 670D61396; Fri, 4 Feb 2022 07:06:26 -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 48B573F774; Fri, 4 Feb 2022 07:06:24 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: ardb@kernel.org, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, frederic@kernel.org, james.morse@arm.com, joey.gouly@arm.com, juri.lelli@redhat.com, linux-kernel@vger.kernel.org, luto@kernel.org, mark.rutland@arm.com, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, valentin.schneider@arm.com, will@kernel.org Subject: [PATCH v2 6/7] arm64: entry: centralize premeption decision Date: Fri, 4 Feb 2022 15:05:56 +0000 Message-Id: <20220204150557.434610-7-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220204150557.434610-1-mark.rutland@arm.com> References: <20220204150557.434610-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220204_070627_285773_6A978D71 X-CRM114-Status: GOOD ( 14.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org For historical reasons, the decision of whether or not to preempt is spread across arm64_preempt_schedule_irq() and __el1_irq(), and it would be clearer if this were all in one place. Also, arm64_preempt_schedule_irq() calls lockdep_assert_irqs_disabled(), but this is redundant, as we have a subsequent identical assertion in __exit_to_kernel_mode(), and preempt_schedule_irq() will BUG_ON(!irqs_disabled()) anyway. This patch removes the redundant assertion and centralizes the preemption decision making within arm64_preempt_schedule_irq(). Other than the slight change to assertion behaviour, there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: James Morse Cc: Joey Gouly Cc: Valentin Schneider Cc: Will Deacon --- arch/arm64/kernel/entry-common.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index ef7fcefb96bd..2c639b6b676d 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -222,7 +222,16 @@ static void noinstr arm64_exit_el1_dbg(struct pt_regs *regs) static void __sched arm64_preempt_schedule_irq(void) { - lockdep_assert_irqs_disabled(); + if (!IS_ENABLED(CONFIG_PREEMPTION)) + return; + + /* + * Note: thread_info::preempt_count includes both thread_info::count + * and thread_info::need_resched, and is not equivalent to + * preempt_count(). + */ + if (READ_ONCE(current_thread_info()->preempt_count) != 0) + return; /* * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC @@ -438,14 +447,7 @@ static __always_inline void __el1_irq(struct pt_regs *regs, do_interrupt_handler(regs, handler); irq_exit_rcu(); - /* - * Note: thread_info::preempt_count includes both thread_info::count - * and thread_info::need_resched, and is not equivalent to - * preempt_count(). - */ - if (IS_ENABLED(CONFIG_PREEMPTION) && - READ_ONCE(current_thread_info()->preempt_count) == 0) - arm64_preempt_schedule_irq(); + arm64_preempt_schedule_irq(); exit_to_kernel_mode(regs); } -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel