The patch titled
x86: enable GART-IOMMU only after setting up protection methods
has been added to the -mm tree. Its filename is
x86-enable-gart-iommu-only-after-setting-up-protection-methods.patch
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------------------------------------------------------
Subject: x86: enable GART-IOMMU only after setting up protection methods
From: Mark Langsdorf <mark.langsdorf@xxxxxxx>
The current code to set up the GART as an IOMMU enables GART translations
before it removes the aperture from the kernel memory map, sets the GART
PTEs to UC, sets up the guard and scratch pages, or does a wbinvd(). This
leaves the possibility of cache aliasing open and can cause system
crashes.
Re-order the code and add tlbflush so as to enable the GART translations
only after all safeguards are in place and the tlb has been flushed.
AMD has tested this patch and seen no adverse effects.
Signed-off-by: Mark Langsdorf <mark.langsdorf@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/pci-gart_64.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff -puN arch/x86/kernel/pci-gart_64.c~x86-enable-gart-iommu-only-after-setting-up-protection-methods arch/x86/kernel/pci-gart_64.c
--- a/arch/x86/kernel/pci-gart_64.c~x86-enable-gart-iommu-only-after-setting-up-protection-methods
+++ a/arch/x86/kernel/pci-gart_64.c
@@ -38,6 +38,7 @@
#include <asm/swiotlb.h>
#include <asm/dma.h>
#include <asm/k8.h>
+#include <asm/tlbflush.h>
static unsigned long iommu_bus_base; /* GART remapping area (physical) */
static unsigned long iommu_size; /* size of remapping area bytes */
@@ -686,9 +687,9 @@ static __init int init_k8_gatt(struct ag
if (set_memory_uc((unsigned long)gatt, gatt_size >> PAGE_SHIFT))
panic("Could not set GART PTEs to uncacheable pages");
- agp_gatt_table = gatt;
+ wbinvd();
- enable_gart_translations();
+ agp_gatt_table = gatt;
error = sysdev_class_register(&gart_sysdev_class);
if (!error)
@@ -859,6 +860,11 @@ void __init gart_iommu_init(void)
for (i = EMERGENCY_PAGES; i < iommu_pages; i++)
iommu_gatt_base[i] = gart_unmapped_entry;
+ wbinvd();
+ flush_tlb_all();
+
+ enable_gart_translations();
+
flush_gart();
dma_ops = &gart_dma_ops;
}
_
Patches currently in -mm which might be from mark.langsdorf@xxxxxxx are
x86-enable-gart-iommu-only-after-setting-up-protection-methods.patch
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