x86: Revert e820 MCFG heuristics The check for the MCFG table being reserved in the e820 map was originally added to detect a broken BIOS in a preproduction Intel SDV. However it also breaks the Apple x86 Macs, which can't supply this properly, but need a working MCFG. With this patch they wouldn't use the MCFG and not work. After some discussion I think it's best to remove the heuristic again. It also failed on some other boxes (although it didn't cause much problems there because old style port access for PCI config space still works as fallback), but the preproduction SDVs can just use pci=nommcfg. Supporting production machines properly is more important. Edgar Hucek did all the debugging work. Cc: Arjan van de Ven Cc: Edgar Hucek Signed-off-by: Andi Kleen --- arch/i386/kernel/setup.c | 32 -------------------------------- arch/i386/pci/mmconfig.c | 9 --------- arch/x86_64/kernel/e820.c | 29 ----------------------------- arch/x86_64/pci/mmconfig.c | 9 --------- 4 files changed, 79 deletions(-) Index: linux/arch/i386/kernel/setup.c =================================================================== --- linux.orig/arch/i386/kernel/setup.c +++ linux/arch/i386/kernel/setup.c @@ -837,38 +837,6 @@ efi_memory_present_wrapper(unsigned long return 0; } - /* - * This function checks if the entire range is mapped with type. - * - * Note: this function only works correct if the e820 table is sorted and - * not-overlapping, which is the case - */ -int __init -e820_all_mapped(unsigned long s, unsigned long e, unsigned type) -{ - u64 start = s; - u64 end = e; - int i; - for (i = 0; i < e820.nr_map; i++) { - struct e820entry *ei = &e820.map[i]; - if (type && ei->type != type) - continue; - /* is the region (part) in overlap with the current region ?*/ - if (ei->addr >= end || ei->addr + ei->size <= start) - continue; - /* if the region is at the beginning of we move - * start to the end of the region since it's ok until there - */ - if (ei->addr <= start) - start = ei->addr + ei->size; - /* if start is now at or beyond end, we're done, full - * coverage */ - if (start >= end) - return 1; /* we're done */ - } - return 0; -} - /* * Find the highest page frame number we have available */ Index: linux/arch/i386/pci/mmconfig.c =================================================================== --- linux.orig/arch/i386/pci/mmconfig.c +++ linux/arch/i386/pci/mmconfig.c @@ -198,15 +198,6 @@ 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_MIN, - E820_RESERVED)) { - printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n", - pci_mmcfg_config[0].base_address); - 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; Index: linux/arch/x86_64/kernel/e820.c =================================================================== --- linux.orig/arch/x86_64/kernel/e820.c +++ linux/arch/x86_64/kernel/e820.c @@ -105,35 +105,6 @@ e820_any_mapped(unsigned long start, uns return 0; } -/* - * This function checks if the entire range is mapped with type. - * - * Note: this function only works correct if the e820 table is sorted and - * not-overlapping, which is the case - */ -int __init e820_all_mapped(unsigned long start, unsigned long end, unsigned type) -{ - int i; - for (i = 0; i < e820.nr_map; i++) { - struct e820entry *ei = &e820.map[i]; - if (type && ei->type != type) - continue; - /* is the region (part) in overlap with the current region ?*/ - if (ei->addr >= end || ei->addr + ei->size <= start) - continue; - - /* if the region is at the beginning of we move - * start to the end of the region since it's ok until there - */ - if (ei->addr <= start) - start = ei->addr + ei->size; - /* if start is now at or beyond end, we're done, full coverage */ - if (start >= end) - return 1; /* we're done */ - } - return 0; -} - /* * Find a free area in a specific range. */ Index: linux/arch/x86_64/pci/mmconfig.c =================================================================== --- linux.orig/arch/x86_64/pci/mmconfig.c +++ linux/arch/x86_64/pci/mmconfig.c @@ -176,15 +176,6 @@ 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_MIN, - E820_RESERVED)) { - printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n", - pci_mmcfg_config[0].base_address); - 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) {