From patchwork Mon Mar 21 12:24:31 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 8632191 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EAB53C0553 for ; Mon, 21 Mar 2016 12:27:15 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EEAA720328 for ; Mon, 21 Mar 2016 12:27:14 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DBBD720306 for ; Mon, 21 Mar 2016 12:27:13 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ahyt7-000185-0g; Mon, 21 Mar 2016 12:24:49 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ahyt5-00016j-BS for xen-devel@lists.xenproject.org; Mon, 21 Mar 2016 12:24:47 +0000 Received: from [85.158.139.211] by server-4.bemta-5.messagelabs.com id AA/27-20731-E08EFE65; Mon, 21 Mar 2016 12:24:46 +0000 X-Env-Sender: jgross@suse.com X-Msg-Ref: server-12.tower-206.messagelabs.com!1458563085!30494858!1 X-Originating-IP: [195.135.220.15] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 8.11; banners=-,-,- X-VirusChecked: Checked Received: (qmail 4028 invoked from network); 21 Mar 2016 12:24:46 -0000 Received: from mx2.suse.de (HELO mx2.suse.de) (195.135.220.15) by server-12.tower-206.messagelabs.com with DHE-RSA-CAMELLIA256-SHA encrypted SMTP; 21 Mar 2016 12:24:46 -0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 204B1AC13; Mon, 21 Mar 2016 12:24:42 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org Date: Mon, 21 Mar 2016 13:24:31 +0100 Message-Id: <1458563075-30298-3-git-send-email-jgross@suse.com> X-Mailer: git-send-email 2.6.2 In-Reply-To: <1458563075-30298-1-git-send-email-jgross@suse.com> References: <1458563075-30298-1-git-send-email-jgross@suse.com> Cc: Juergen Gross , jeremy@goop.org, jdelvare@suse.com, peterz@infradead.org, hpa@zytor.com, akataria@vmware.com, x86@kernel.org, rusty@rustcorp.com.au, virtualization@lists.linux-foundation.org, chrisw@sous-sol.org, mingo@redhat.com, david.vrabel@citrix.com, Douglas_Warzecha@dell.com, pali.rohar@gmail.com, boris.ostrovsky@oracle.com, tglx@linutronix.de, linux@roeck-us.net Subject: [Xen-devel] [PATCH v2 2/6] smp: add function to execute a function synchronously on a physical cpu X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On some hardware models (e.g. Dell Studio 1555 laptop) some hardware related functions (e.g. SMIs) are to be executed on physical cpu 0 only. Instead of open coding such a functionality multiple times in the kernel add a service function for this purpose. This will enable the possibility to take special measures in virtualized environments like Xen, too. Signed-off-by: Juergen Gross --- V2: instead of manipulating the allowed set of cpus use cpu specific workqueue as requested by Peter Zijlstra --- include/linux/smp.h | 2 ++ kernel/smp.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ kernel/up.c | 9 +++++++++ 3 files changed, 55 insertions(+) diff --git a/include/linux/smp.h b/include/linux/smp.h index c441407..fc9d21b 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -196,4 +196,6 @@ extern void arch_enable_nonboot_cpus_end(void); void smp_setup_processor_id(void); +int smp_call_sync_on_phys_cpu(unsigned int cpu, int (*func)(void *), void *par); + #endif /* __LINUX_SMP_H */ diff --git a/kernel/smp.c b/kernel/smp.c index 7416544..62da74b 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -739,3 +739,47 @@ void wake_up_all_idle_cpus(void) preempt_enable(); } EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); + +/** + * smp_call_sync_on_phys_cpu - Call a function on a specific physical cpu + * + * Used to call a function on a specific physical cpu. Even if the specified + * cpu isn't the current one, return only after the called function has + * returned. + */ +struct smp_sync_call_struct { + struct work_struct work; + struct completion done; + int (*func)(void *); + void *data; + int ret; +}; + +static void smp_call_sync_callback(struct work_struct *work) +{ + struct smp_sync_call_struct *sscs; + + sscs = container_of(work, struct smp_sync_call_struct, work); + sscs->ret = sscs->func(sscs->data); + + complete(&sscs->done); +} + +int smp_call_sync_on_phys_cpu(unsigned int cpu, int (*func)(void *), void *par) +{ + struct smp_sync_call_struct sscs = { + .work = __WORK_INITIALIZER(sscs.work, smp_call_sync_callback), + .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done), + .func = func, + .data = par, + }; + + if (cpu >= nr_cpu_ids) + return -EINVAL; + + queue_work_on(cpu, system_wq, &sscs.work); + wait_for_completion(&sscs.done); + + return sscs.ret; +} +EXPORT_SYMBOL_GPL(smp_call_sync_on_phys_cpu); diff --git a/kernel/up.c b/kernel/up.c index 1760bf3..afd395c 100644 --- a/kernel/up.c +++ b/kernel/up.c @@ -82,3 +82,12 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), preempt_enable(); } EXPORT_SYMBOL(on_each_cpu_cond); + +int smp_call_sync_on_phys_cpu(unsigned int cpu, int (*func)(void *), void *par) +{ + if (cpu != 0) + return -EINVAL; + + return func(par); +} +EXPORT_SYMBOL_GPL(smp_call_sync_on_phys_cpu);