From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760240AbYDOINX (ORCPT ); Tue, 15 Apr 2008 04:13:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754615AbYDOINM (ORCPT ); Tue, 15 Apr 2008 04:13:12 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:57441 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753976AbYDOINL (ORCPT ); Tue, 15 Apr 2008 04:13:11 -0400 Date: Tue, 15 Apr 2008 01:12:47 -0700 From: Andrew Morton To: yhlu.kernel@gmail.com Cc: Yinghai Lu , Thomas Gleixner , Ingo Molnar , "Eric W. Biederman" , Jeff Garzik , Ayaz Abdulla , kernel list Subject: Re: [PATCH] x86_64: restore mask_bits in msi shutdown Message-Id: <20080415011247.4b6020e7.akpm@linux-foundation.org> In-Reply-To: <200804111626.11232.yhlu.kernel@gmail.com> References: <200804111626.11232.yhlu.kernel@gmail.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 11 Apr 2008 16:26:11 -0700 Yinghai Lu wrote: > I can not kexec RHEL 5.1 from 2.6.25-rc3 later > > caused by: > commit 89d694b9dbe769ca1004e01db0ca43964806a611 > Author: Thomas Gleixner > Date: Mon Feb 18 18:25:17 2008 +0100 > > genirq: do not leave interupts enabled on free_irq > > The default_disable() function was changed in commit: > > 76d2160147f43f982dfe881404cfde9fd0a9da21 > genirq: do not mask interrupts by default > > It removed the mask function in favour of the default delayed > interrupt disabling. Unfortunately this also broke the shutdown in > free_irq() when the last handler is removed from the interrupt for > those architectures which rely on the default implementations. Now we > can end up with a enabled interrupt line after the last handler was > removed, which can result in spurious interrupts. > > Fix this by adding a default_shutdown function, which is only > installed, when the irqchip implementation does provide neither a > shutdown nor a disable function. > > [@stable: affected versions: .21 - .24 ] > > > > for MSI, default_shutdown will call mask_bit for msi device. so all mask bits will > left disabled after free_irq. > then if kexec next kernel that only can use msi_enable bit. > all device's MSI can not be used. > > So try to restore MSI mask bits that is saved before using msi in first kernel. > > Signed-off-by: Yinghai Lu > > Index: linux-2.6/arch/x86/kernel/io_apic_64.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/io_apic_64.c > +++ linux-2.6/arch/x86/kernel/io_apic_64.c > @@ -2003,6 +2003,14 @@ static void set_msi_irq_affinity(unsigne > } > #endif /* CONFIG_SMP */ > > +static void msi_shutdown(unsigned int irq) > +{ > + struct irq_desc *desc = irq_desc + irq; > + > + msi_restore_mask_bits(irq); > + desc->status |= IRQ_MASKED; > +} I wonder if only x86_64 needs this treatment. > Index: linux-2.6/drivers/pci/msi.c > =================================================================== > --- linux-2.6.orig/drivers/pci/msi.c > +++ linux-2.6/drivers/pci/msi.c > @@ -123,6 +123,31 @@ static void msix_flush_writes(unsigned i > } > } > > +void msi_restore_mask_bits(unsigned int irq) > +{ > + struct msi_desc *entry; > + > + entry = get_irq_msi(irq); > + BUG_ON(!entry || !entry->dev); > + switch (entry->msi_attrib.type) { > + case PCI_CAP_ID_MSI: > + if (entry->msi_attrib.maskbit) { > + int pos; > + u32 mask_bits; > + > + pos = (long)entry->mask_base; > + mask_bits = entry->orig_mask_bits; > + pci_write_config_dword(entry->dev, pos, mask_bits); > + } > + break; > + case PCI_CAP_ID_MSIX: > + break; > + default: > + BUG(); > + break; > + } > +} If no other architectures will ever need this, perhaps it is in the wrong file.