Attachment 313699 Details for Bug 455813 – RHEL5 fix for this issue

[patch] RHEL5 fix for this issue

455813-v3.patch (text/plain), 10.50 KB, created by Prarit Bhargava on 2008-08-07 15:03:07 UTC

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Creator: Prarit Bhargava

Created: 2008-08-07 15:03:07 UTC

Size: 10.50 KB

patch

obsolete

>pci_alloc_consistent/dma_alloc_coherent is supposed to 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.  Backport upstream iommu-helper code into RHEL5.
>
>While #1 was being done, two bugs were noted:
>
>2.  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.
>
>3.  Fix the GART's alloc_iommu code to return a size aligned address.
>
>(Patch for 2 & 3 was sent upstream and is in jbarnes' for-linus PCI tree)
>
>Patch was tested with a similar test module provided in BZ 298811.
>
>Resolves BZ 455813.
>
>diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c
>index 565ee9b..1c4c523 100644
>--- a/arch/x86_64/kernel/pci-gart.c
>+++ b/arch/x86_64/kernel/pci-gart.c
>@@ -22,6 +22,7 @@
> #include <linux/topology.h>
> #include <linux/interrupt.h>
> #include <linux/bitops.h>
>+#include <linux/iommu-helper.h>
> #include <asm/atomic.h>
> #include <asm/io.h>
> #include <asm/mtrr.h>
>@@ -76,37 +77,50 @@ 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(int size) 
>-{ 	
>+static unsigned long alloc_iommu(struct device *dev, int size,
>+				 unsigned long mask)
>+{
> 	unsigned long offset, flags;
>+	unsigned long boundary_size;
>+	unsigned long base_index;
>+
>+	base_index = ALIGN(iommu_bus_base & 0xffffffff,
>+			   PAGE_SIZE) >> PAGE_SHIFT;
>+	boundary_size = ALIGN((unsigned long long) 0x100000000,
>+			      PAGE_SIZE) >> PAGE_SHIFT;
> 
>-	spin_lock_irqsave(&iommu_bitmap_lock, flags);	
>-	offset = find_next_zero_string(iommu_gart_bitmap,next_bit,iommu_pages,size);
>+	spin_lock_irqsave(&iommu_bitmap_lock, flags);
>+	offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, next_bit,
>+				  size, base_index, boundary_size, mask);
> 	if (offset == -1) {
> 		need_flush = 1;
>-		offset = find_next_zero_string(iommu_gart_bitmap,0,iommu_pages,size);
>+		offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, 0,
>+					  size, base_index, boundary_size,
>+					  mask);
> 	}
>-	if (offset != -1) { 
>-		set_bit_string(iommu_gart_bitmap, offset, size); 
>-		next_bit = offset+size; 
>-		if (next_bit >= iommu_pages) { 
>+	if (offset != -1) {
>+		set_bit_string(iommu_gart_bitmap, offset, size);
>+		next_bit = offset+size;
>+		if (next_bit >= iommu_pages) {
> 			next_bit = 0;
> 			need_flush = 1;
>-		} 
>-	} 
>+		}
>+	}
> 	if (iommu_fullflush)
> 		need_flush = 1;
>-	spin_unlock_irqrestore(&iommu_bitmap_lock, flags);      
>+	spin_unlock_irqrestore(&iommu_bitmap_lock, flags);
>+
> 	return offset;
>-} 
>+}
> 
> static void free_iommu(unsigned long offset, int size)
>-{ 
>+{
> 	unsigned long flags;
>+
> 	spin_lock_irqsave(&iommu_bitmap_lock, flags);
>-	__clear_bit_string(iommu_gart_bitmap, offset, size);
>+	iommu_area_free(iommu_gart_bitmap, offset, size);
> 	spin_unlock_irqrestore(&iommu_bitmap_lock, flags);
>-} 
>+}
> 
> /* 
>  * Use global flush state to avoid races with multiple flushers.
>@@ -204,10 +218,11 @@ static inline int nonforced_iommu(struct device *dev, unsigned long addr, size_t
>  * 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(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) {
> 		if (!nonforced_iommu(dev, phys_mem, size))
>@@ -223,13 +238,15 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
> 		SET_LEAK(iommu_page + i);
> 		phys_mem += PAGE_SIZE;
> 	}
>+
> 	return iommu_bus_base + iommu_page*PAGE_SIZE + (phys_mem & ~PAGE_MASK);
> }
> 
> static dma_addr_t gart_map_simple(struct device *dev, char *buf,
> 				 size_t size, int dir)
> {
>-	dma_addr_t map = dma_map_area(dev, virt_to_bus(buf), size, dir);
>+	dma_addr_t map = dma_map_area(dev, virt_to_bus(buf), size, dir,
>+				      size - 1);
> 	flush_gart();
> 	return map;
> }
>@@ -248,7 +265,9 @@ dma_addr_t gart_map_single(struct device *dev, void *addr, size_t size, int dir)
> 	if (!need_iommu(dev, phys_mem, size))
> 		return phys_mem; 
> 
>-	bus = gart_map_simple(dev, addr, size, dir);
>+	bus = dma_map_area(dev, virt_to_bus(addr), size, dir, 0);
>+	flush_gart();
>+
> 	return bus; 
> }
> 
>@@ -303,7 +322,7 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
> 		struct scatterlist *s = &sg[i];
> 		unsigned long addr = page_to_phys(s->page) + s->offset; 
> 		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);
>@@ -320,10 +339,11 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
> }
> 
> /* Map multiple scatterlist entries continuous into the first. */
>-static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
>-		      struct scatterlist *sout, unsigned long pages)
>+static int __dma_map_cont(struct device *dev, struct scatterlist *sg, int start,
>+			  int stopat, struct scatterlist *sout,
>+			  unsigned long pages)
> {
>-	unsigned long iommu_start = alloc_iommu(pages);
>+	unsigned long iommu_start = alloc_iommu(dev, pages, 0);
> 	unsigned long iommu_page = iommu_start; 
> 	int i;
> 
>@@ -358,9 +378,10 @@ static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
> 	return 0;
> }
> 
>-static inline int dma_map_cont(struct scatterlist *sg, int start, int stopat,
>-		      struct scatterlist *sout,
>-		      unsigned long pages, int need)
>+static inline int dma_map_cont(struct device *dev, struct scatterlist *sg,
>+			       int start, int stopat,
>+			       struct scatterlist *sout,
>+			       unsigned long pages, int need)
> {
> 	if (!need) { 
> 		BUG_ON(stopat - start != 1);
>@@ -368,7 +389,7 @@ static inline int dma_map_cont(struct scatterlist *sg, int start, int stopat,
> 		sout->dma_length = sg[start].length; 
> 		return 0;
> 	} 
>-	return __dma_map_cont(sg, start, stopat, sout, pages);
>+	return __dma_map_cont(dev, sg, start, stopat, sout, pages);
> }
> 		
> /*
>@@ -407,8 +428,8 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
> 			   boundary and the new one doesn't have an offset. */
> 			if (!iommu_merge || !nextneed || !need || s->offset ||
> 			    (ps->offset + ps->length) % PAGE_SIZE) { 
>-				if (dma_map_cont(sg, start, i, sg+out, pages,
>-						 need) < 0)
>+				if (dma_map_cont(dev, sg, start, i, sg+out,
>+						 pages, need) < 0)
> 					goto error;
> 				out++;
> 				pages = 0;
>@@ -419,7 +440,7 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
> 		need = nextneed;
> 		pages += to_pages(s->offset, s->length);
> 	}
>-	if (dma_map_cont(sg, start, i, sg+out, pages, need) < 0)
>+	if (dma_map_cont(dev, sg, start, i, sg+out, pages, need) < 0)
> 		goto error;
> 	out++;
> 	flush_gart();
>diff --git a/lib/Makefile b/lib/Makefile
>index 09891f6..7f0cdc7 100644
>--- a/lib/Makefile
>+++ b/lib/Makefile
>@@ -55,6 +55,8 @@ obj-$(CONFIG_SMP) += percpu_counter.o
> obj-$(CONFIG_AUDIT_GENERIC) += audit.o
> 
> obj-$(CONFIG_SWIOTLB) += swiotlb.o
>+obj-$(CONFIG_IOMMU) += iommu-helper.o
>+
> ifeq ($(CONFIG_X86),y)
> swiotlb-$(CONFIG_XEN) := ../arch/i386/kernel/swiotlb.o
> endif
>diff --git a/include/linux/iommu-helper.h b/include/linux/iommu-helper.h
>new file mode 100644
>index 0000000..c975caf
>--- /dev/null
>+++ b/include/linux/iommu-helper.h
>@@ -0,0 +1,10 @@
>+extern int iommu_is_span_boundary(unsigned int index, unsigned int nr,
>+				  unsigned long shift,
>+				  unsigned long boundary_size);
>+extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
>+				      unsigned long start, unsigned int nr,
>+				      unsigned long shift,
>+				      unsigned long boundary_size,
>+				      unsigned long align_mask);
>+extern void iommu_area_free(unsigned long *map, unsigned long start,
>+			    unsigned int nr);
>diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
>new file mode 100644
>index 0000000..e0c0e76
>--- /dev/null
>+++ b/lib/iommu-helper.c
>@@ -0,0 +1,81 @@
>+/*
>+ * IOMMU helper functions for the free area management
>+ */
>+
>+#include <linux/module.h>
>+#include <linux/bitops.h>
>+
>+static unsigned long find_next_zero_area(unsigned long *map,
>+					 unsigned long size,
>+					 unsigned long start,
>+					 unsigned int nr,
>+					 unsigned long align_mask)
>+{
>+	unsigned long index, end, i;
>+again:
>+	index = find_next_zero_bit(map, size, start);
>+
>+	/* Align allocation */
>+	index = (index + (align_mask + 1)) & ~align_mask;
>+	end = index + nr;
>+	if (end >= size)
>+		return -1;
>+	for (i = index; i < end; i++) {
>+		if (test_bit(i, map)) {
>+			start = i+1;
>+			goto again;
>+		}
>+	}
>+	return index;
>+}
>+
>+static inline void set_bit_area(unsigned long *map, unsigned long i,
>+				int len)
>+{
>+	unsigned long end = i + len;
>+	while (i < end) {
>+		__set_bit(i, map);
>+		i++;
>+	}
>+}
>+
>+int iommu_is_span_boundary(unsigned int index, unsigned int nr,
>+			   unsigned long shift,
>+			   unsigned long boundary_size)
>+{
>+	BUG_ON(!is_power_of_2(boundary_size));
>+
>+	shift = (shift + index) & (boundary_size - 1);
>+	return shift + nr > boundary_size;
>+}
>+
>+unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
>+			       unsigned long start, unsigned int nr,
>+			       unsigned long shift, unsigned long boundary_size,
>+			       unsigned long align_mask)
>+{
>+	unsigned long index = 0;
>+again:
>+	index = find_next_zero_area(map, size, start, nr, align_mask);
>+	if (index != -1) {
>+		if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
>+			/* we could do more effectively */
>+			start = index + 1;
>+			goto again;
>+		}
>+		set_bit_area(map, index, nr);
>+	}
>+	return index;
>+}
>+EXPORT_SYMBOL(iommu_area_alloc);
>+
>+void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
>+{
>+	unsigned long end = start + nr;
>+
>+	while (start < end) {
>+		__clear_bit(start, map);
>+		start++;
>+	}
>+}
>+EXPORT_SYMBOL(iommu_area_free);

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Attachments on bug 455813: 312088 | 312089 | 312135 | 312136 | 312164 | 312463 | 313699