Messages in this thread | | | Date | Tue, 15 Apr 2008 01:12:47 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] x86_64: restore mask_bits in msi shutdown |
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On Fri, 11 Apr 2008 16:26:11 -0700 Yinghai Lu <yhlu.kernel.send@gmail.com> wrote:
> I can not kexec RHEL 5.1 from 2.6.25-rc3 later > > caused by: > commit 89d694b9dbe769ca1004e01db0ca43964806a611 > Author: Thomas Gleixner <tglx@linutronix.de> > 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 <yhlu.kernel@gmail.com> > > 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.
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