Revert mmiocfg heuristics and blacklist changes

This reverts commits 11012d419cfc0e0f78ca356aca03674217910124 and
40dd2d20f220eda1cd0da8ea3f0f9db8971ba237, which allowed us to use the
MMIO accesses for PCI config cycles even without the area being marked
reserved in the e820 memory tables.

Those changes were needed for EFI-environment Intel macs, but broke some
newer Intel 965 boards, so for now it's better to revert to our old
2.6.17 behaviour and at least avoid introducing any new breakage.

Andi Kleen has a set of patches that work with both EFI and the broken
Intel 965 boards, which will be applied once they get wider testing.

Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Edgar Hucek <hostmaster@ed-soft.at>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 39 insertions, 24 deletions

diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
index 764bf23c7103..d6d7f731f6f0 100644
--- a/arch/x86_64/kernel/e820.c
+++ b/arch/x86_64/kernel/e820.c
@@ -108,6 +108,35 @@ e820_any_mapped(unsigned long start, unsigned long end, unsigned type)
         return 0;
 }
 
+/*
+ * This function checks if the entire range <start,end> 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 <start,end> 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. 
  */ 
diff --git a/arch/x86_64/pci/mmconfig.c b/arch/x86_64/pci/mmconfig.c
index 2d48a7941d48..3c55c76c6fd5 100644
--- a/arch/x86_64/pci/mmconfig.c
+++ b/arch/x86_64/pci/mmconfig.c
@@ -9,7 +9,6 @@
 #include <linux/init.h>
 #include <linux/acpi.h>
 #include <linux/bitmap.h>
-#include <linux/dmi.h>
 #include <asm/e820.h>
 
 #include "pci.h"
@@ -165,33 +164,11 @@ static __init void unreachable_devices(void)
         }
 }
 
-static int disable_mcfg(struct dmi_system_id *d)
-{
-        printk("PCI: %s detected. Disabling MCFG.\n", d->ident);
-        pci_probe &= ~PCI_PROBE_MMCONF;
-        return 0;
-}
-
-static struct dmi_system_id __initdata dmi_bad_mcfg[] = {
-        /* Has broken MCFG table that makes the system hang when used */
-        {
-         .callback = disable_mcfg,
-         .ident = "Intel D3C5105 SDV",
-         .matches = {
-                     DMI_MATCH(DMI_BIOS_VENDOR, "Intel"),
-                     DMI_MATCH(DMI_BOARD_NAME, "D26928"),
-                     },
-         },
-         {}
-};
-
 void __init pci_mmcfg_init(void)
 {
         int i;
 
-        dmi_check_system(dmi_bad_mcfg);
-
-        if ((pci_probe & (PCI_PROBE_MMCONF|PCI_PROBE_MMCONF_FORCE)) == 0)
+        if ((pci_probe & PCI_PROBE_MMCONF) == 0)
                 return;
 
         acpi_table_parse(ACPI_MCFG, acpi_parse_mcfg);
@@ -200,6 +177,15 @@ 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) {