From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 , Len Brown , Pavel Machek , x86@kernel.org Cc: Jiang Liu , Konrad Rzeszutek Wilk , Andrew Morton , Tony Luck , Joerg Roedel , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org Subject: [Patch v4 11/16] x86, irq, ACPI: Introduce a rwsem to protect IOAPIC operations from hotplug Date: Thu, 28 Aug 2014 10:22:36 +0800 Message-Id: <1409192561-19744-12-git-send-email-jiang.liu@linux.intel.com> In-Reply-To: <1409192561-19744-1-git-send-email-jiang.liu@linux.intel.com> References: <1409192561-19744-1-git-send-email-jiang.liu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 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 | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index b436fc735aa4..e23f7460c3f8 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -76,6 +76,8 @@ int acpi_fix_pin2_polarity __initdata; static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; #endif +static DECLARE_RWSEM(acpi_ioapic_rwsem); + /* -------------------------------------------------------------------------- Boot-time Configuration -------------------------------------------------------------------------- */ @@ -604,8 +606,11 @@ 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 +651,9 @@ 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 +662,9 @@ 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 +1190,9 @@ 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(); -- 1.7.10.4