From patchwork Tue Jan 22 07:40:51 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 214431 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 6BF1D2C17FB for ; Tue, 22 Jan 2013 19:05:17 +1100 (EST) Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp06.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 6E8B92C0221 for ; Tue, 22 Jan 2013 18:42:56 +1100 (EST) Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 22 Jan 2013 17:38:57 +1000 Received: from d23dlp02.au.ibm.com (202.81.31.213) by e23smtp06.au.ibm.com (202.81.31.212) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 22 Jan 2013 17:38:55 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id A9FCD2BB004F for ; Tue, 22 Jan 2013 18:42:53 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0M7grhV63701246 for ; Tue, 22 Jan 2013 18:42:53 +1100 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0M7gpme025125 for ; Tue, 22 Jan 2013 18:42:53 +1100 Received: from srivatsabhat.in.ibm.com (srivatsabhat.in.ibm.com [9.124.35.112]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r0M7garS024838; Tue, 22 Jan 2013 18:42:38 +1100 From: "Srivatsa S. Bhat" Subject: [PATCH v5 29/45] x86/xen: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org Date: Tue, 22 Jan 2013 13:10:51 +0530 Message-ID: <20130122074046.13822.61950.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13012207-7014-0000-0000-0000027FF92B Cc: linux-arch@vger.kernel.org, linux@arm.linux.org.uk, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, fweisbec@gmail.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, rjw@sisk.pl, sbw@mit.edu, wangyun@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Once stop_machine() is gone from the CPU offline path, we won't be able to depend on preempt_disable() or local_irq_disable() to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Konrad Rzeszutek Wilk Cc: Jeremy Fitzhardinge Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: xen-devel@lists.xensource.com Cc: virtualization@lists.linux-foundation.org Signed-off-by: Srivatsa S. Bhat --- arch/x86/xen/mmu.c | 11 +++++++++-- arch/x86/xen/smp.c | 9 +++++++++ 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 01de35c..6a95a15 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -39,6 +39,7 @@ * Jeremy Fitzhardinge , XenSource Inc, 2007 */ #include +#include #include #include #include @@ -1163,9 +1164,13 @@ static void xen_drop_mm_ref(struct mm_struct *mm) */ static void xen_exit_mmap(struct mm_struct *mm) { - get_cpu(); /* make sure we don't move around */ + /* + * Make sure we don't move around, and prevent CPUs from going + * offline. + */ + get_online_cpus_atomic(); xen_drop_mm_ref(mm); - put_cpu(); + put_online_cpus_atomic(); spin_lock(&mm->page_table_lock); @@ -1371,6 +1376,7 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, args->op.arg2.vcpumask = to_cpumask(args->mask); /* Remove us, and any offline CPUS. */ + get_online_cpus_atomic(); cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask)); @@ -1383,6 +1389,7 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF); xen_mc_issue(PARAVIRT_LAZY_MMU); + put_online_cpus_atomic(); } static unsigned long xen_read_cr3(void) diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 4f7d259..7d753ae 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -487,8 +488,10 @@ static void __xen_send_IPI_mask(const struct cpumask *mask, { unsigned cpu; + get_online_cpus_atomic(); for_each_cpu_and(cpu, mask, cpu_online_mask) xen_send_IPI_one(cpu, vector); + put_online_cpus_atomic(); } static void xen_smp_send_call_function_ipi(const struct cpumask *mask) @@ -551,8 +554,10 @@ void xen_send_IPI_all(int vector) { int xen_vector = xen_map_vector(vector); + get_online_cpus_atomic(); if (xen_vector >= 0) __xen_send_IPI_mask(cpu_online_mask, xen_vector); + put_online_cpus_atomic(); } void xen_send_IPI_self(int vector) @@ -572,20 +577,24 @@ void xen_send_IPI_mask_allbutself(const struct cpumask *mask, if (!(num_online_cpus() > 1)) return; + get_online_cpus_atomic(); for_each_cpu_and(cpu, mask, cpu_online_mask) { if (this_cpu == cpu) continue; xen_smp_send_call_function_single_ipi(cpu); } + put_online_cpus_atomic(); } void xen_send_IPI_allbutself(int vector) { int xen_vector = xen_map_vector(vector); + get_online_cpus_atomic(); if (xen_vector >= 0) xen_send_IPI_mask_allbutself(cpu_online_mask, xen_vector); + put_online_cpus_atomic(); } static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)