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/i386/pci/mmconfig.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/i386/pci') diff --git a/arch/i386/pci/mmconfig.c b/arch/i386/pci/mmconfig.c index 613789071f3..ee815c7d3e4 100644 --- a/arch/i386/pci/mmconfig.c +++ b/arch/i386/pci/mmconfig.c @@ -12,8 +12,11 @@ #include #include #include +#include #include "pci.h" +#define MMCONFIG_APER_SIZE (256*1024*1024) + #define mmcfg_virt_addr ((void __iomem *) fix_to_virt(FIX_PCIE_MCFG)) /* The base address of the last MMCONFIG device accessed */ @@ -183,6 +186,14 @@ 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; + } + printk(KERN_INFO "PCI: Using MMCONFIG\n"); raw_pci_ops = &pci_mmcfg; pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF; -- cgit v1.2.3