From patchwork Thu Nov 3 20:23:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 80731 Delivered-To: patch@linaro.org Received: by 10.140.97.247 with SMTP id m110csp826791qge; Thu, 3 Nov 2016 13:27:30 -0700 (PDT) X-Received: by 10.98.16.203 with SMTP id 72mr19976694pfq.57.1478204850398; Thu, 03 Nov 2016 13:27:30 -0700 (PDT) Return-Path: Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id b4si9543108pan.289.2016.11.03.13.27.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Nov 2016 13:27:30 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) client-ip=2001:1868:205::9; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) smtp.mailfrom=linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1c2Oah-0003j8-VD; Thu, 03 Nov 2016 20:26:27 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1c2OYb-0001GR-6B for linux-arm-kernel@lists.infradead.org; Thu, 03 Nov 2016 20:24:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1B80715AD; Thu, 3 Nov 2016 13:23:50 -0700 (PDT) Received: from localhost.localdomain (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 016993F318; Thu, 3 Nov 2016 13:23:48 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [PATCHv2 08/11] arm64: smp: prepare for smp_processor_id() rework Date: Thu, 3 Nov 2016 20:23:10 +0000 Message-Id: <1478204593-29145-9-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1478204593-29145-1-git-send-email-mark.rutland@arm.com> References: <1478204593-29145-1-git-send-email-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161103_132417_425013_A2B0474A X-CRM114-Status: GOOD ( 10.33 ) X-Spam-Score: -8.3 (--------) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-8.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [217.140.101.70 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, lorenzo.pieralisi@arm.com, keescook@chromium.org, ard.biesheuvel@linaro.org, catalin.marinas@arm.com, suzuki.poulose@arm.com, will.deacon@arm.com, takahiro.akashi@linaro.org, james.morse@arm.com, luto@kernel.org, labbott@redhat.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org Subsequent patches will make smp_processor_id() use a percpu variable. This will make smp_processor_id() dependent on the percpu offset, and thus we cannot use smp_processor_id() to figure out what to initialise the offset to. Prepare for this by initialising the percpu offset based on current::cpu, which will work regardless of how smp_processor_id() is implemented. Also, make this relationship obvious by placing this code together at the start of secondary_start_kernel(). Signed-off-by: Mark Rutland Tested-by: Laura Abbott Cc: Catalin Marinas Cc: Will Deacon --- arch/arm64/kernel/smp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 8507703..f64401f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -208,7 +208,10 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) asmlinkage void secondary_start_kernel(void) { struct mm_struct *mm = &init_mm; - unsigned int cpu = smp_processor_id(); + unsigned int cpu; + + cpu = task_cpu(current); + set_my_cpu_offset(per_cpu_offset(cpu)); /* * All kernel threads share the same mm context; grab a @@ -217,8 +220,6 @@ asmlinkage void secondary_start_kernel(void) atomic_inc(&mm->mm_count); current->active_mm = mm; - set_my_cpu_offset(per_cpu_offset(smp_processor_id())); - /* * TTBR0 is only used for the identity mapping at this stage. Make it * point to zero page to avoid speculatively fetching new entries.