From 946f2ee5c7312e8acac4f3ab6629e7e2d36a3646 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Fri, 7 Apr 2006 19:49:30 +0200 Subject: [PATCH] i386/x86-64: Check that MCFG points to an e820 reserved area 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 Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/pci/mmconfig.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/x86_64/pci/mmconfig.c') diff --git a/arch/x86_64/pci/mmconfig.c b/arch/x86_64/pci/mmconfig.c index e616500207e4..dfe84c322552 100644 --- a/arch/x86_64/pci/mmconfig.c +++ b/arch/x86_64/pci/mmconfig.c @@ -9,6 +9,8 @@ #include #include #include +#include + #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_ERR "PCI: BIOS Bug: MCFG area is not E820-reserved\n"); + printk(KERN_ERR "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) { -- cgit v1.2.3-59-g8ed1b