x86, gart: Make sure GART does not map physmem above 1TB

BugLink: http://bugs.launchpad.net/bugs/775809

commit 665d3e2af83c8fbd149534db8f57d82fa6fa6753 upstream.

The GART can only map physical memory below 1TB. Make sure
the gart driver in the kernel does not try to map memory
above 1TB.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-5-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index c01ffa5..197a46f 100644 (file)
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -81,6 +81,9 @@ static u32 gart_unmapped_entry;
 #define AGPEXTERN
 #endif
 
+/* GART can only remap to physical addresses < 1TB */
+#define GART_MAX_PHYS_ADDR     (1ULL << 40)
+
 /* backdoor interface to AGP driver */
 AGPEXTERN int agp_memory_reserved;
 AGPEXTERN __u32 *agp_gatt_table;
@@ -212,9 +215,13 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
                                size_t size, int dir, unsigned long align_mask)
 {
        unsigned long npages = iommu_num_pages(phys_mem, size, PAGE_SIZE);
-       unsigned long iommu_page = alloc_iommu(dev, npages, align_mask);
+       unsigned long iommu_page;
        int i;
 
+       if (unlikely(phys_mem + size > GART_MAX_PHYS_ADDR))
+               return bad_dma_addr;
+
+       iommu_page = alloc_iommu(dev, npages, align_mask);
        if (iommu_page == -1) {
                if (!nonforced_iommu(dev, phys_mem, size))
                        return phys_mem;