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Commit 946f2ee5 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Linus Torvalds
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[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: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 95222368

arch/i386/pci/mmconfig.c

+11 −0
Original line number Diff line number Diff line
@@ -12,8 +12,11 @@ 
#include <linux/pci.h>

#include <linux/init.h>

#include <linux/acpi.h>

#include <asm/e820.h>

#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;

arch/x86_64/pci/mmconfig.c

+10 −0
Original line number Diff line number Diff line
@@ -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_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) {