[PATCH] x86_64: Check for too many northbridges in IOMMU code

The IOMMU code can only deal with 8 northbridges. Error out when
more are found.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c
index 9d3d76c85ae7..2480d3f08a47 100644
--- a/arch/x86_64/kernel/pci-gart.c
+++ b/arch/x86_64/kernel/pci-gart.c
@@ -639,6 +639,14 @@ static int __init pci_iommu_init(void)
                 return -1;
         }
 
+        i = 0;
+        for_all_nb(dev)
+                i++;
+        if (i > MAX_NB) {
+                printk(KERN_ERR "PCI-GART: Too many northbridges (%ld). Disabled\n", i);
+                return -1;
+        }
+
         printk(KERN_INFO "PCI-DMA: using GART IOMMU.\n");
         aper_size = info.aper_size * 1024 * 1024;       
         iommu_size = check_iommu_size(info.aper_base, aper_size);