Don't rely on BAR contents when the command register says the BAR is disabled. If we receive a PCI device from firmware (or a hot-added device that was just powered up) with the MEMORY or IO enable bits in the PCI command register cleared, there's no reason to believe the BARs contain valid addresses. In that case, we still know the type and size of the BAR, but this patch marks the resource as "unset" so we have a chance to reassign it. Historically, we often used "BAR == 0" to decide the BAR is invalid. But 0 is a legal BAR value, especially if the host bridge translates addresses, so I think it's better to decide based on the PCI command register, and store the conclusion in the IORESOURCE_UNSET bit. Reference: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=679545 Reference: https://bugzilla.kernel.org/show_bug.cgi?id=48451 Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> --- drivers/pci/probe.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 6e34498ec9f0..02654b5ec1b9 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -177,9 +177,10 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, mask = type ? PCI_ROM_ADDRESS_MASK : ~0; + pci_read_config_word(dev, PCI_COMMAND, &orig_cmd); + /* No printks while decoding is disabled! */ if (!dev->mmio_always_on) { - pci_read_config_word(dev, PCI_COMMAND, &orig_cmd); if (orig_cmd & PCI_COMMAND_DECODE_ENABLE) { pci_write_config_word(dev, PCI_COMMAND, orig_cmd & ~PCI_COMMAND_DECODE_ENABLE); @@ -215,9 +216,13 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, if (res->flags & IORESOURCE_IO) { l &= PCI_BASE_ADDRESS_IO_MASK; mask = PCI_BASE_ADDRESS_IO_MASK & (u32) IO_SPACE_LIMIT; + if (!(orig_cmd & PCI_COMMAND_IO)) + res->flags |= IORESOURCE_UNSET; } else { l &= PCI_BASE_ADDRESS_MEM_MASK; mask = (u32)PCI_BASE_ADDRESS_MEM_MASK; + if (!(orig_cmd & PCI_COMMAND_MEMORY)) + res->flags |= IORESOURCE_UNSET; } } else { res->flags |= (l & IORESOURCE_ROM_ENABLE); @@ -252,6 +257,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, /* Address above 32-bit boundary; disable the BAR */ pci_write_config_dword(dev, pos, 0); pci_write_config_dword(dev, pos + 4, 0); + res->flags |= IORESOURCE_UNSET; region.start = 0; region.end = sz64; bar_disabled = true; -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
