From patchwork Wed Sep 8 19:06:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Packard X-Patchwork-Id: 508255 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.9 required=3.0 tests=BAYES_00,DKIM_ADSP_ALL, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81881C433F5 for ; Wed, 8 Sep 2021 19:06:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62996610A3 for ; Wed, 8 Sep 2021 19:06:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350070AbhIHTHe (ORCPT ); Wed, 8 Sep 2021 15:07:34 -0400 Received: from home.keithp.com ([63.227.221.253]:35678 "EHLO elaine.keithp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350414AbhIHTH3 (ORCPT ); Wed, 8 Sep 2021 15:07:29 -0400 Received: from localhost (localhost [127.0.0.1]) by elaine.keithp.com (Postfix) with ESMTP id C1B3A3F3088B; Wed, 8 Sep 2021 12:05:51 -0700 (PDT) X-Virus-Scanned: Debian amavisd-new at keithp.com Received: from elaine.keithp.com ([127.0.0.1]) by localhost (elaine.keithp.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id hA43RMvmbiP7; Wed, 8 Sep 2021 12:05:51 -0700 (PDT) Received: from keithp.com (168-103-156-98.tukw.qwest.net [168.103.156.98]) by elaine.keithp.com (Postfix) with ESMTPSA id 2D6443F30884; Wed, 8 Sep 2021 12:05:49 -0700 (PDT) Received: by keithp.com (Postfix, from userid 1000) id 61B2C1E6013B; Wed, 8 Sep 2021 12:06:09 -0700 (PDT) From: Keith Packard To: linux-kernel@vger.kernel.org Cc: Abbott Liu , Alexei Starovoitov , Andrew Morton , Andrii Nakryiko , Anshuman Khandual , Ard Biesheuvel , Arnd Bergmann , Ben Segall , Bjorn Andersson , bpf@vger.kernel.org, Christoph Lameter , Daniel Borkmann , Daniel Bristot de Oliveira , Dennis Zhou , devicetree@vger.kernel.org, Dietmar Eggemann , Florian Fainelli , Frank Rowand , Geert Uytterhoeven , Ingo Molnar , Jason Wang , Jens Axboe , Joe Perches , John Fastabend , Juri Lelli , Keith Packard , KP Singh , kvm@vger.kernel.org, Linus Walleij , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, Manivannan Sadhasivam , Marc Zyngier , Martin KaFai Lau , Mel Gorman , Michael Ellerman , "Michael S. Tsirkin" , Miguel Ojeda , Mike Rapoport , netdev@vger.kernel.org, Nick Desaulniers , Nick Desaulniers , Nicolas Pitre , Peter Zijlstra , Rob Herring , Russell King , Song Liu , Srikar Dronamraju , Steven Rostedt , Tejun Heo , Thomas Gleixner , =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= , Valentin Schneider , Vincent Guittot , virtualization@lists.linux-foundation.org, "Wolfram Sang (Renesas)" , YiFei Zhu , Yonghong Song Subject: [PATCH v4 5/7] ARM: Stop using TPIDRPRW to hold per_cpu_offset Date: Wed, 8 Sep 2021 12:06:03 -0700 Message-Id: <20210908190605.419064-6-keithpac@amazon.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210908190605.419064-1-keithpac@amazon.com> References: <20210908190605.419064-1-keithpac@amazon.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We're going to store TPIDRPRW here instead Signed-off-by: Keith Packard --- arch/arm/include/asm/percpu.h | 31 ------------------------------- arch/arm/kernel/setup.c | 7 ------- arch/arm/kernel/smp.c | 3 --- 3 files changed, 41 deletions(-) diff --git a/arch/arm/include/asm/percpu.h b/arch/arm/include/asm/percpu.h index e2fcb3cfd3de..eeafcd6a3e01 100644 --- a/arch/arm/include/asm/percpu.h +++ b/arch/arm/include/asm/percpu.h @@ -7,37 +7,6 @@ register unsigned long current_stack_pointer asm ("sp"); -/* - * Same as asm-generic/percpu.h, except that we store the per cpu offset - * in the TPIDRPRW. TPIDRPRW only exists on V6K and V7 - */ -#if defined(CONFIG_SMP) && !defined(CONFIG_CPU_V6) -static inline void set_my_cpu_offset(unsigned long off) -{ - /* Set TPIDRPRW */ - asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory"); -} - -static inline unsigned long __my_cpu_offset(void) -{ - unsigned long off; - - /* - * Read TPIDRPRW. - * We want to allow caching the value, so avoid using volatile and - * instead use a fake stack read to hazard against barrier(). - */ - asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off) - : "Q" (*(const unsigned long *)current_stack_pointer)); - - return off; -} -#define __my_cpu_offset __my_cpu_offset() -#else -#define set_my_cpu_offset(x) do {} while(0) - -#endif /* CONFIG_SMP */ - #include #endif /* _ASM_ARM_PERCPU_H_ */ diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index ca0201635fac..d0dc60afe54f 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -590,13 +590,6 @@ void __init smp_setup_processor_id(void) for (i = 1; i < nr_cpu_ids; ++i) cpu_logical_map(i) = i == cpu ? 0 : i; - /* - * clear __my_cpu_offset on boot CPU to avoid hang caused by - * using percpu variable early, for example, lockdep will - * access percpu variable inside lock_release - */ - set_my_cpu_offset(0); - pr_info("Booting Linux on physical CPU 0x%x\n", mpidr); } diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 5e999f1f1aea..8ccf10b34f08 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -410,8 +410,6 @@ asmlinkage void secondary_start_kernel(unsigned int cpu, struct task_struct *tas { struct mm_struct *mm = &init_mm; - set_my_cpu_offset(per_cpu_offset(cpu)); - secondary_biglittle_init(); /* @@ -495,7 +493,6 @@ void __init smp_cpus_done(unsigned int max_cpus) void __init smp_prepare_boot_cpu(void) { - set_my_cpu_offset(per_cpu_offset(smp_processor_id())); } void __init smp_prepare_cpus(unsigned int max_cpus)