x86, gart: Set DISTLBWALKPRB bit always

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

commit c34151a742d84ae65db2088ea30495063f697fbe upstream.

The DISTLBWALKPRB bit must be set for the GART because the
gatt table is mapped UC. But the current code does not set
the bit at boot when the BIOS setup the aperture correctly.
Fix that by setting this bit when enabling the GART instead
of the other places.

Cc: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1303134346-5805-4-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/include/asm/gart.h b/arch/x86/include/asm/gart.h
index 43085bf..3e7349f 100644 (file)
--- a/arch/x86/include/asm/gart.h
+++ b/arch/x86/include/asm/gart.h
@@ -66,7 +66,7 @@ static inline void gart_set_size_and_enable(struct pci_dev *dev, u32 order)
         * Don't enable translation but enable GART IO and CPU accesses.
         * Also, set DISTLBWALKPRB since GART tables memory is UC.
         */
-       ctl = DISTLBWALKPRB | order << 1;
+       ctl = order << 1;
 
        pci_write_config_dword(dev, AMD64_GARTAPERTURECTL, ctl);
 }
@@ -83,7 +83,7 @@ static inline void enable_gart_translation(struct pci_dev *dev, u64 addr)
 
         /* Enable GART translation for this hammer. */
         pci_read_config_dword(dev, AMD64_GARTAPERTURECTL, &ctl);
-        ctl |= GARTEN;
+        ctl |= GARTEN | DISTLBWALKPRB;
         ctl &= ~(DISGARTCPU | DISGARTIO);
         pci_write_config_dword(dev, AMD64_GARTAPERTURECTL, ctl);
 }

diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 5955a78..f6a1c23 100644 (file)
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -500,7 +500,7 @@ out:
                 * Don't enable translation yet but enable GART IO and CPU
                 * accesses and set DISTLBWALKPRB since GART table memory is UC.
                 */
-               u32 ctl = DISTLBWALKPRB | aper_order << 1;
+               u32 ctl = aper_order << 1;
 
                bus = amd_nb_bus_dev_ranges[i].bus;
                dev_base = amd_nb_bus_dev_ranges[i].dev_base;