From 9a08f7d3506019e3833cd4394ca0d7da0ae3689f Mon Sep 17 00:00:00 2001
From: Bjorn Helgaas <bjorn.helgaas@hp.com>
Date: Fri, 23 Oct 2009 15:20:33 -0600
Subject: x86/PCI: allow MMCONFIG above 4GB

The current whitelist requires a kernel change for every machine that has
MMCONFIG regions above 4GB, even if BIOS provides a correct MCFG table.

This patch expands the whitelist to include machines with a rev 1 or newer
MCFG table and a DMI_BIOS_DATE of 2010 or later.  That way, we only need
kernel changes for new machines that provide incorrect MCFG tables.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
CC: Matthew Wilcox <willy@linux.intel.com>
CC: John Keller <jpk@sgi.com>
CC: Yinghai Lu <yhlu.kernel@gmail.com>
CC: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
CC: Andi Kleen <andi@firstfloor.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 602c172..0264277 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -15,6 +15,7 @@
 #include <linux/acpi.h>
 #include <linux/sfi_acpi.h>
 #include <linux/bitmap.h>
+#include <linux/dmi.h>
 #include <linux/sort.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
@@ -527,18 +528,31 @@ reject:
 
 static int __initdata known_bridge;
 
-static int acpi_mcfg_64bit_base_addr __initdata = FALSE;
-
 /* The physical address of the MMCONFIG aperture.  Set from ACPI tables. */
 struct acpi_mcfg_allocation *pci_mmcfg_config;
 int pci_mmcfg_config_num;
 
-static int __init acpi_mcfg_oem_check(struct acpi_table_mcfg *mcfg)
+static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
+					struct acpi_mcfg_allocation *cfg)
 {
+	int year;
+
+	if (cfg->address < 0xFFFFFFFF)
+		return 0;
+
 	if (!strcmp(mcfg->header.oem_id, "SGI"))
-		acpi_mcfg_64bit_base_addr = TRUE;
+		return 0;
 
-	return 0;
+	if (mcfg->header.revision >= 1) {
+		if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) &&
+		    year >= 2010)
+			return 0;
+	}
+
+	printk(KERN_ERR PREFIX "MCFG region for %04x:%02x-%02x at %#llx "
+	       "is above 4GB, ignored\n", cfg->pci_segment,
+	       cfg->start_bus_number, cfg->end_bus_number, cfg->address);
+	return -EINVAL;
 }
 
 static int __init pci_parse_mcfg(struct acpi_table_header *header)
@@ -574,13 +588,8 @@ static int __init pci_parse_mcfg(struct acpi_table_header *header)
 
 	memcpy(pci_mmcfg_config, &mcfg[1], config_size);
 
-	acpi_mcfg_oem_check(mcfg);
-
 	for (i = 0; i < pci_mmcfg_config_num; ++i) {
-		if ((pci_mmcfg_config[i].address > 0xFFFFFFFF) &&
-		    !acpi_mcfg_64bit_base_addr) {
-			printk(KERN_ERR PREFIX
-			       "MMCONFIG not in low 4GB of memory\n");
+		if (acpi_mcfg_check_entry(mcfg, &pci_mmcfg_config[i])) {
 			kfree(pci_mmcfg_config);
 			pci_mmcfg_config_num = 0;
 			return -ENODEV;
-- 
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