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authorBorislav Petkov <borislav.petkov@amd.com>2010-09-03 18:39:40 +0200
committerIngo Molnar <mingo@elte.hu>2010-09-05 14:28:34 +0200
commit260133ab658bd2b80e07832a878e00405e19ff43 (patch)
treec48b062b77416348c268f80df7c294f35f35588f /arch/x86/kernel/aperture_64.c
parent57ab43e33122ffdc2eebca5d6de035699f0a8c06 (diff)
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x86, GART: Disable GART table walk probes
Current code tramples over bit F3x90[6] which can be used to disable GART table walk probes. However, this bit should be set for performance reasons (speed up GART table walks). We are allowed to do that since we put GART tables in UC memory later anyway. Make it so. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> Cc: Dave Airlie <airlied@redhat.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> LKML-Reference: <1283531981-7495-3-git-send-email-bp@amd64.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/aperture_64.c')
-rw-r--r--arch/x86/kernel/aperture_64.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 6fabd406aa7..c9cb1736844 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -505,8 +505,13 @@ out:
/* Fix up the north bridges */
for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {
- int bus;
- int dev_base, dev_limit;
+ int bus, dev_base, dev_limit;
+
+ /*
+ * 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;
bus = bus_dev_ranges[i].bus;
dev_base = bus_dev_ranges[i].dev_base;
@@ -515,10 +520,7 @@ out:
if (!early_is_k8_nb(read_pci_config(bus, slot, 3, 0x00)))
continue;
- /* Don't enable translation yet. That is done later.
- Assume this BIOS didn't initialise the GART so
- just overwrite all previous bits */
- write_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL, aper_order << 1);
+ write_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL, ctl);
write_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE, aper_alloc >> 25);
}
}