From patchwork Thu Sep 11 08:05:54 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiang Liu X-Patchwork-Id: 388103 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 00CA614011D for ; Thu, 11 Sep 2014 18:08:23 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753268AbaIKIHp (ORCPT ); Thu, 11 Sep 2014 04:07:45 -0400 Received: from mga09.intel.com ([134.134.136.24]:35740 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752732AbaIKIEI (ORCPT ); Thu, 11 Sep 2014 04:04:08 -0400 Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP; 11 Sep 2014 00:58:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,504,1406617200"; d="scan'208";a="601322555" Received: from gerry-dev.bj.intel.com ([10.238.158.74]) by orsmga002.jf.intel.com with ESMTP; 11 Sep 2014 01:04:01 -0700 From: Jiang Liu To: Benjamin Herrenschmidt , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Rafael J. Wysocki" , Bjorn Helgaas , Randy Dunlap , Yinghai Lu , Borislav Petkov , Grant Likely Cc: Jiang Liu , Konrad Rzeszutek Wilk , Andrew Morton , Tony Luck , Joerg Roedel , Greg Kroah-Hartman , x86@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org Subject: [Patch v5 11/15] x86, irq, ACPI: Introduce a rwsem to protect IOAPIC operations from hotplug Date: Thu, 11 Sep 2014 16:05:54 +0800 Message-Id: <1410422758-24942-12-git-send-email-jiang.liu@linux.intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1410422758-24942-1-git-send-email-jiang.liu@linux.intel.com> References: <1410422758-24942-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org We are going to support ACPI based IOAPIC hotplug, so introduce a rwsem to protect IOAPIC data structures from IOAPIC hotplug. We choose to serialize in ACPI instead of in the IOAPIC core because: 1) currently we are only plan to support ACPI based IOAPIC hotplug 2) it's much more cleaner and easier 3) It does't affect IOAPIC discovered by devicetree, SFI and mpparse. Signed-off-by: Jiang Liu --- arch/x86/kernel/acpi/boot.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index b436fc735aa4..c598fd7604d5 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -76,6 +76,19 @@ int acpi_fix_pin2_polarity __initdata; static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; #endif +/* + * Locks related to IOAPIC hotplug + * Hotplug side: + * ->lock_device_hotplug() //device_hotplug_lock + * ->acpi_ioapic_rwsem + * ->ioapic_lock + * Interrupt mapping side: + * ->acpi_ioapic_rwsem + * ->ioapic_mutex + * ->ioapic_lock + */ +static DECLARE_RWSEM(acpi_ioapic_rwsem); + /* -------------------------------------------------------------------------- Boot-time Configuration -------------------------------------------------------------------------- */ @@ -604,8 +617,11 @@ void __init acpi_pic_sci_set_trigger(unsigned int irq, u16 trigger) int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp) { - int irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK); + int irq; + down_read(&acpi_ioapic_rwsem); + irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK); + up_read(&acpi_ioapic_rwsem); if (irq >= 0) { *irqp = irq; return 0; @@ -646,7 +662,9 @@ static int acpi_register_gsi_ioapic(struct device *dev, u32 gsi, int irq = gsi; #ifdef CONFIG_X86_IO_APIC + down_read(&acpi_ioapic_rwsem); irq = mp_register_gsi(dev, gsi, trigger, polarity); + up_read(&acpi_ioapic_rwsem); #endif return irq; @@ -655,7 +673,9 @@ static int acpi_register_gsi_ioapic(struct device *dev, u32 gsi, static void acpi_unregister_gsi_ioapic(u32 gsi) { #ifdef CONFIG_X86_IO_APIC + down_read(&acpi_ioapic_rwsem); mp_unregister_gsi(gsi); + up_read(&acpi_ioapic_rwsem); #endif } @@ -1181,7 +1201,9 @@ static void __init acpi_process_madt(void) /* * Parse MADT IO-APIC entries */ + down_write(&acpi_ioapic_rwsem); error = acpi_parse_madt_ioapic_entries(); + up_write(&acpi_ioapic_rwsem); if (!error) { acpi_set_irq_model_ioapic();