From patchwork Wed Sep 8 19:05:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Packard X-Patchwork-Id: 508256 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 2DC57C433EF for ; Wed, 8 Sep 2021 19:06:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E471606A5 for ; Wed, 8 Sep 2021 19:06:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350419AbhIHTH1 (ORCPT ); Wed, 8 Sep 2021 15:07:27 -0400 Received: from home.keithp.com ([63.227.221.253]:35456 "EHLO elaine.keithp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350339AbhIHTHX (ORCPT ); Wed, 8 Sep 2021 15:07:23 -0400 Received: from localhost (localhost [127.0.0.1]) by elaine.keithp.com (Postfix) with ESMTP id 5A9873F30881; Wed, 8 Sep 2021 12:05:48 -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 VY1FZb1c7sU8; Wed, 8 Sep 2021 12:05:47 -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 56FE93F30883; Wed, 8 Sep 2021 12:05:47 -0700 (PDT) Received: by keithp.com (Postfix, from userid 1000) id 50A2E1E60122; 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 1/7] ARM: Pass cpu number to secondary_start_kernel Date: Wed, 8 Sep 2021 12:05:59 -0700 Message-Id: <20210908190605.419064-2-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 Instead of pulling the CPU value out of the thread_info struct, pass it as an argument. When first initializing secondary processors, this is done by stashing the value in the secondary_data struct. When restarting idle processors, the previous CPU value is passed. Because the cpu is now known at the top of secondary_start_kernel, the per_cpu_offset value can now be set at this point, instead of in cpu_init where it was also incorrectly setting the per_cpu_offset for the boot processor before that value had been computed. Signed-off-by: Keith Packard Reviewed-by: Ard Biesheuvel --- arch/arm/include/asm/smp.h | 3 ++- arch/arm/kernel/head-nommu.S | 1 + arch/arm/kernel/head.S | 1 + arch/arm/kernel/setup.c | 6 ------ arch/arm/kernel/smp.c | 14 +++++++++----- 5 files changed, 13 insertions(+), 12 deletions(-) diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h index 5d508f5d56c4..86a7fd721556 100644 --- a/arch/arm/include/asm/smp.h +++ b/arch/arm/include/asm/smp.h @@ -48,7 +48,7 @@ extern void set_smp_ipi_range(int ipi_base, int nr_ipi); * Called from platform specific assembly code, this is the * secondary CPU entry point. */ -asmlinkage void secondary_start_kernel(void); +asmlinkage void secondary_start_kernel(unsigned int cpu); /* @@ -61,6 +61,7 @@ struct secondary_data { }; unsigned long swapper_pg_dir; void *stack; + unsigned int cpu; }; extern struct secondary_data secondary_data; extern void secondary_startup(void); diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S index 0fc814bbc34b..5aa8ef42717f 100644 --- a/arch/arm/kernel/head-nommu.S +++ b/arch/arm/kernel/head-nommu.S @@ -114,6 +114,7 @@ ENTRY(secondary_startup) add r12, r12, r10 ret r12 1: bl __after_proc_init + ldr r0, [r7, #16] @ set up cpu number ldr sp, [r7, #12] @ set up the stack pointer mov fp, #0 b secondary_start_kernel diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 7f62c5eccdf3..0e541af738e2 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -394,6 +394,7 @@ ENDPROC(secondary_startup_arm) ENTRY(__secondary_switched) ldr_l r7, secondary_data + 12 @ get secondary_data.stack + ldr_l r0, secondary_data + 16 @ get secondary_data.cpu mov sp, r7 mov fp, #0 b secondary_start_kernel diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 73ca7797b92f..ca0201635fac 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -532,12 +532,6 @@ void notrace cpu_init(void) BUG(); } - /* - * This only works on resume and secondary cores. For booting on the - * boot cpu, smp_prepare_boot_cpu is called after percpu area setup. - */ - set_my_cpu_offset(per_cpu_offset(cpu)); - cpu_proc_init(); /* diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 74679240a9d8..55cb1689a4b3 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -153,6 +153,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) secondary_data.pgdir = virt_to_phys(idmap_pgd); secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir); #endif + secondary_data.cpu = cpu; sync_cache_w(&secondary_data); /* @@ -373,11 +374,14 @@ void arch_cpu_idle_dead(void) * cpu initialisation. There's some initialisation which needs * to be repeated to undo the effects of taking the CPU offline. */ - __asm__("mov sp, %0\n" + __asm__("mov r0, %1\n" + " mov sp, %0\n" " mov fp, #0\n" " b secondary_start_kernel" : - : "r" (task_stack_page(current) + THREAD_SIZE - 8)); + : "r" (task_stack_page(current) + THREAD_SIZE - 8), + "r" (cpu) + : "r0"); } #endif /* CONFIG_HOTPLUG_CPU */ @@ -400,10 +404,11 @@ static void smp_store_cpu_info(unsigned int cpuid) * This is the secondary CPU boot entry. We're using this CPUs * idle thread stack, but a set of temporary page tables. */ -asmlinkage void secondary_start_kernel(void) +asmlinkage void secondary_start_kernel(unsigned int cpu) { struct mm_struct *mm = &init_mm; - unsigned int cpu; + + set_my_cpu_offset(per_cpu_offset(cpu)); secondary_biglittle_init(); @@ -420,7 +425,6 @@ asmlinkage void secondary_start_kernel(void) * All kernel threads share the same mm context; grab a * reference and switch to it. */ - cpu = smp_processor_id(); mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm));