Messages in this thread Patch in this message | | | Subject | [patch 3 of 4] MCFG sanity check | From | Arjan van de Ven <> | Date | Sat, 25 Mar 2006 17:24:58 +0100 |
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This patch introduces a user for the e820_all_mapped function:
There have been several machines that don't have a working MMCONFIG, often because of a buggy MCFG table in the ACPI bios. This patch adds a simple sanity check that detects a whole bunch of these cases, and when it detects it, linux now boots rather than crash-and-burns. The accuracy of this detection can in principle be improved if there was a "is this entire range in e820 with THIS attribute", but no such function exist and the complexity needed for this is not really worth it; this simple check already catches most cases anyway.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> --- arch/x86_64/pci/mmconfig.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
Index: linux-2.6.16-mmconfig/arch/x86_64/pci/mmconfig.c =================================================================== --- linux-2.6.16-mmconfig.orig/arch/x86_64/pci/mmconfig.c +++ linux-2.6.16-mmconfig/arch/x86_64/pci/mmconfig.c @@ -9,6 +9,8 @@ #include <linux/init.h> #include <linux/acpi.h> #include <linux/bitmap.h> +#include <asm/e820.h> + #include "pci.h" #define MMCONFIG_APER_SIZE (256*1024*1024) @@ -161,6 +163,14 @@ void __init pci_mmcfg_init(void) (pci_mmcfg_config[0].base_address == 0)) return; + if (!e820_all_mapped(pci_mmcfg_config[0].base_address, + pci_mmcfg_config[0].base_address + MMCONFIG_APER_SIZE, + E820_RESERVED)) { + printk(KERN_INFO "PCI: BIOS Bug: MCFG area is not E820-reserved\n"); + printk(KERN_INFO "PCI: Not using MMCONFIG.\n"); + return; + } + /* RED-PEN i386 doesn't do _nocache right now */ pci_mmcfg_virt = kmalloc(sizeof(*pci_mmcfg_virt) * pci_mmcfg_config_num, GFP_KERNEL); if (pci_mmcfg_virt == NULL) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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