From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755286Ab3HWI7a (ORCPT ); Fri, 23 Aug 2013 04:59:30 -0400 Received: from mail-oa0-f48.google.com ([209.85.219.48]:35967 "EHLO mail-oa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755172Ab3HWI71 (ORCPT ); Fri, 23 Aug 2013 04:59:27 -0400 From: Liu Ping Fan To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Kevin Hao Subject: [PATCH] x86: ioapic needs check attr when programmed more than once Date: Fri, 23 Aug 2013 16:58:47 +0800 Message-Id: <1377248327-19633-1-git-send-email-pingfank@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When programming ioapic pinX more than once, current code does not check whether the later attr (trigger&polarity) is the same as the former or not. This causes a broken semantic. This can be observed in qemu q35 machine, where ioapic's ioredtbl[x] can never be set as low-active, even if the hpet driver registered it. And hpet driver may share a high-level active IRQ line with other device. So in qemu, when hpet-dev asserts low-level as kernel expects, the kernel has no response. With this patch, we can observe an ioredtbl[x] set as low-active for hpet. Fix it by reporting -EBUSY to the caller, when attr is different. Signed-off-by: Liu Ping Fan --- arch/x86/kernel/acpi/boot.c | 5 ++++- arch/x86/kernel/apic/io_apic.c | 7 ++++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 230c8ea..9ef2ce9 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1113,6 +1113,7 @@ int mp_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity) int ioapic; int ioapic_pin; struct io_apic_irq_attr irq_attr; + int ret; if (acpi_irq_model != ACPI_IRQ_MODEL_IOAPIC) return gsi; @@ -1142,7 +1143,9 @@ int mp_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity) set_io_apic_irq_attr(&irq_attr, ioapic, ioapic_pin, trigger == ACPI_EDGE_SENSITIVE ? 0 : 1, polarity == ACPI_ACTIVE_HIGH ? 0 : 1); - io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr); + ret = io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr); + if (ret < 0) + gsi = INT_MIN; return gsi; } diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 9ed796c..ce31d902 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -3375,12 +3375,17 @@ int io_apic_setup_irq_pin_once(unsigned int irq, int node, { unsigned int ioapic_idx = attr->ioapic, pin = attr->ioapic_pin; int ret; + struct IO_APIC_route_entry orig; /* Avoid redundant programming */ if (test_bit(pin, ioapics[ioapic_idx].pin_programmed)) { pr_debug("Pin %d-%d already programmed\n", mpc_ioapic_id(ioapic_idx), pin); - return 0; + orig = ioapic_read_entry(attr->ioapic, pin); + if (attr->trigger == orig.trigger && + attr->polarity == orig.polarity) + return 0; + return -EBUSY; } ret = io_apic_setup_irq_pin(irq, node, attr); if (!ret) -- 1.8.1.4