From patchwork Fri Dec 6 10:17:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinjie Ruan X-Patchwork-Id: 13896828 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 51A7EE7717F for ; Fri, 6 Dec 2024 10:18:28 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.849985.1264472 (Exim 4.92) (envelope-from ) id 1tJVPf-0002Q8-27; Fri, 06 Dec 2024 10:18:19 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 849985.1264472; Fri, 06 Dec 2024 10:18:19 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tJVPe-0002Lp-Sd; Fri, 06 Dec 2024 10:18:18 +0000 Received: by outflank-mailman (input) for mailman id 849985; Fri, 06 Dec 2024 10:18:17 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tJVPd-0001of-86 for xen-devel@lists.xenproject.org; Fri, 06 Dec 2024 10:18:17 +0000 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 67195428-b3bb-11ef-a0d5-8be0dac302b0; Fri, 06 Dec 2024 11:18:16 +0100 (CET) Received: from mail.maildlp.com (unknown [172.19.163.48]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4Y4Rw20yXpz1V4WK; Fri, 6 Dec 2024 18:15:14 +0800 (CST) Received: from kwepemg200008.china.huawei.com (unknown [7.202.181.35]) by mail.maildlp.com (Postfix) with ESMTPS id 318F818009B; Fri, 6 Dec 2024 18:18:13 +0800 (CST) Received: from huawei.com (10.90.53.73) by kwepemg200008.china.huawei.com (7.202.181.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 6 Dec 2024 18:18:11 +0800 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 67195428-b3bb-11ef-a0d5-8be0dac302b0 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH -next v5 05/22] arm64: entry: Use preempt_count() and need_resched() helper Date: Fri, 6 Dec 2024 18:17:27 +0800 Message-ID: <20241206101744.4161990-6-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241206101744.4161990-1-ruanjinjie@huawei.com> References: <20241206101744.4161990-1-ruanjinjie@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemg200008.china.huawei.com (7.202.181.35) The generic entry code uses preempt_count() and need_resched() helpers to check if it is time to resched. Currently, arm64 use its own check logic, that is "READ_ONCE(current_thread_info()->preempt_count == 0", which is equivalent to "preempt_count() == 0 && need_resched()". In preparation for moving arm64 over to the generic entry code, use these helpers to replace arm64's own code and move it ahead. No functional changes. Signed-off-by: Jinjie Ruan --- arch/arm64/kernel/entry-common.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index da68c089b74b..efd1a990d138 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -88,14 +88,6 @@ static inline bool arm64_need_resched(void) if (!need_irq_preemption()) return false; - /* - * 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 false; - /* * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC * priority masking is used the GIC irqchip driver will clear DAIF.IF @@ -141,8 +133,10 @@ static __always_inline void __exit_to_kernel_mode(struct pt_regs *regs, return; } - if (arm64_need_resched()) - preempt_schedule_irq(); + if (!preempt_count() && need_resched()) { + if (arm64_need_resched()) + preempt_schedule_irq(); + } trace_hardirqs_on(); } else {