Prarit, what's the latest here? The v3 patch I have from you doesn't apply to
my tree but it looks like a good fix. Care to send me a new patch against my
for-linus branch?
New patch.
pci_alloc_consistent/dma_alloc_coherent does not return size aligned
addresses.
>From Documentation/DMA-mapping.txt:
"pci_alloc_consistent returns two values: the virtual address which you
can use to access it from the CPU and dma_handle which you pass to the
card.
The cpu return address and the DMA bus master address are both
guaranteed to be aligned to the smallest PAGE_SIZE order which
is greater than or equal to the requested size. This invariant
exists (for example) to guarantee that if you allocate a chunk
which is smaller than or equal to 64 kilobytes, the extent of the
buffer you receive will not cross a 64K boundary."
1. Modify alloc_iommu to allow for an alignment mask
2. Modify pci_gart_simple to return size-aligned values.
3. Fix possible overflow in alloc_iommu's boundary_size calculation.
(It is possible that alloc_iommu()'s boundary_size overflows as
dma_get_seg_boundary can return 0xffffffff. In that case, further usage of
boundary_size triggers a BUG_ON() in the iommu code.)
End result: When allocating from IOMMU, pci_alloc_consistent/dma_alloc_coherent
will now return a size aligned value.
Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index 744126e..d3eb527 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -85,7 +85,8 @@ AGPEXTERN __u32 *agp_gatt_table;
static unsigned long next_bit; /* protected by iommu_bitmap_lock */
static int need_flush; /* global flush state. set for each gart wrap */
-static unsigned long alloc_iommu(struct device *dev, int size)
+static unsigned long alloc_iommu(struct device *dev, int size,
+ unsigned long mask)
{
unsigned long offset, flags;
unsigned long boundary_size;
@@ -93,16 +94,17 @@ static unsigned long alloc_iommu(struct device *dev, int size)
base_index = ALIGN(iommu_bus_base & dma_get_seg_boundary(dev),
PAGE_SIZE) >> PAGE_SHIFT;
- boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
+ boundary_size = ALIGN((unsigned long long)dma_get_seg_boundary(dev) + 1,
PAGE_SIZE) >> PAGE_SHIFT;
spin_lock_irqsave(&iommu_bitmap_lock, flags);
offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, next_bit,
- size, base_index, boundary_size, 0);
+ size, base_index, boundary_size, mask);
if (offset == -1) {
need_flush = 1;
offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, 0,
- size, base_index, boundary_size, 0);
+ size, base_index, boundary_size,
+ mask);
}
if (offset != -1) {
next_bit = offset+size;
@@ -239,10 +241,11 @@ nonforced_iommu(struct device *dev, unsigned long addr, size_t size)
* Caller needs to check if the iommu is needed and flush.
*/
static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
- size_t size, int dir)
+ size_t size, int dir, u64 align_mask)
{
unsigned long npages = to_pages(phys_mem, size);
- unsigned long iommu_page = alloc_iommu(dev, npages);
+ unsigned long palign_mask = align_mask >> PAGE_SHIFT;
+ unsigned long iommu_page = alloc_iommu(dev, npages, palign_mask);
int i;
if (iommu_page == -1) {
@@ -265,7 +268,7 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
static dma_addr_t
gart_map_simple(struct device *dev, phys_addr_t paddr, size_t size, int dir)
{
- dma_addr_t map = dma_map_area(dev, paddr, size, dir);
+ dma_addr_t map = dma_map_area(dev, paddr, size, dir, size - 1);
flush_gart();
@@ -284,7 +287,8 @@ gart_map_single(struct device *dev, phys_addr_t paddr, size_t size, int dir)
if (!need_iommu(dev, paddr, size))
return paddr;
- bus = gart_map_simple(dev, paddr, size, dir);
+ bus = dma_map_area(dev, paddr, size, dir, 0);
+ flush_gart();
return bus;
}
@@ -343,7 +347,7 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
unsigned long addr = sg_phys(s);
if (nonforced_iommu(dev, addr, s->length)) {
- addr = dma_map_area(dev, addr, s->length, dir);
+ addr = dma_map_area(dev, addr, s->length, dir, 0);
if (addr == bad_dma_address) {
if (i > 0)
gart_unmap_sg(dev, sg, i, dir);
@@ -365,7 +369,7 @@ static int __dma_map_cont(struct device *dev, struct scatterlist *start,
int nelems, struct scatterlist *sout,
unsigned long pages)
{
- unsigned long iommu_start = alloc_iommu(dev, pages);
+ unsigned long iommu_start = alloc_iommu(dev, pages, 0);
unsigned long iommu_page = iommu_start;
struct scatterlist *s;
int i;
