svn commit: r191201 - in head/sys: amd64/amd64 arm/arm i386/i386 ia64/ia64

[John Baldwin]

Author: jhb
Date: Fri Apr 17 13:22:18 2009
New Revision: 191201
URL: http://svn.freebsd.org/changeset/base/191201

Log:
  Restore bus DMA bounce pages to an offset of 0 when they are released by
  a tag that has BUS_DMA_KEEP_PG_OFFSET set.  Otherwise the page could be
  reused with a non-zero offset by a tag that doesn't have
  BUS_DMA_KEEP_PG_OFFSET leading to data corruption.
  
  Sleuthing by:	avg
  Reviewed by:	scottl

Modified:
  head/sys/amd64/amd64/busdma_machdep.c
  head/sys/arm/arm/busdma_machdep.c
  head/sys/i386/i386/busdma_machdep.c
  head/sys/ia64/ia64/busdma_machdep.c

Modified: head/sys/amd64/amd64/busdma_machdep.c
==============================================================================
--- head/sys/amd64/amd64/busdma_machdep.c	Fri Apr 17 11:30:32 2009	(r191200)
+++ head/sys/amd64/amd64/busdma_machdep.c	Fri Apr 17 13:22:18 2009	(r191201)
@@ -1137,9 +1137,7 @@ add_bounce_page(bus_dma_tag_t dmat, bus_
 	mtx_unlock(&bounce_lock);
 
 	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
-		/* page offset needs to be preserved */
-		bpage->vaddr &= ~PAGE_MASK;
-		bpage->busaddr &= ~PAGE_MASK;
+		/* Page offset needs to be preserved. */
 		bpage->vaddr |= vaddr & PAGE_MASK;
 		bpage->busaddr |= vaddr & PAGE_MASK;
 	}
@@ -1158,6 +1156,15 @@ free_bounce_page(bus_dma_tag_t dmat, str
 	bz = dmat->bounce_zone;
 	bpage->datavaddr = 0;
 	bpage->datacount = 0;
+	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
+		/*
+		 * Reset the bounce page to start at offset 0.  Other uses
+		 * of this bounce page may need to store a full page of
+		 * data and/or assume it starts on a page boundary.
+		 */
+		bpage->vaddr &= ~PAGE_MASK;
+		bpage->busaddr &= ~PAGE_MASK;
+	}
 
 	mtx_lock(&bounce_lock);
 	STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);

Modified: head/sys/arm/arm/busdma_machdep.c
==============================================================================
--- head/sys/arm/arm/busdma_machdep.c	Fri Apr 17 11:30:32 2009	(r191200)
+++ head/sys/arm/arm/busdma_machdep.c	Fri Apr 17 13:22:18 2009	(r191201)
@@ -1427,9 +1427,7 @@ add_bounce_page(bus_dma_tag_t dmat, bus_
 	mtx_unlock(&bounce_lock);
 
 	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
-		/* page offset needs to be preserved */
-		bpage->vaddr &= ~PAGE_MASK;
-		bpage->busaddr &= ~PAGE_MASK;
+		/* Page offset needs to be preserved. */
 		bpage->vaddr |= vaddr & PAGE_MASK;
 		bpage->busaddr |= vaddr & PAGE_MASK;
 	}
@@ -1448,6 +1446,15 @@ free_bounce_page(bus_dma_tag_t dmat, str
 	bz = dmat->bounce_zone;
 	bpage->datavaddr = 0;
 	bpage->datacount = 0;
+	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
+		/*
+		 * Reset the bounce page to start at offset 0.  Other uses
+		 * of this bounce page may need to store a full page of
+		 * data and/or assume it starts on a page boundary.
+		 */
+		bpage->vaddr &= ~PAGE_MASK;
+		bpage->busaddr &= ~PAGE_MASK;
+	}
 
 	mtx_lock(&bounce_lock);
 	STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);

Modified: head/sys/i386/i386/busdma_machdep.c
==============================================================================
--- head/sys/i386/i386/busdma_machdep.c	Fri Apr 17 11:30:32 2009	(r191200)
+++ head/sys/i386/i386/busdma_machdep.c	Fri Apr 17 13:22:18 2009	(r191201)
@@ -1155,9 +1155,7 @@ add_bounce_page(bus_dma_tag_t dmat, bus_
 	mtx_unlock(&bounce_lock);
 
 	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
-		/* page offset needs to be preserved */
-		bpage->vaddr &= ~PAGE_MASK;
-		bpage->busaddr &= ~PAGE_MASK;
+		/* Page offset needs to be preserved. */
 		bpage->vaddr |= vaddr & PAGE_MASK;
 		bpage->busaddr |= vaddr & PAGE_MASK;
 	}
@@ -1176,6 +1174,15 @@ free_bounce_page(bus_dma_tag_t dmat, str
 	bz = dmat->bounce_zone;
 	bpage->datavaddr = 0;
 	bpage->datacount = 0;
+	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
+		/*
+		 * Reset the bounce page to start at offset 0.  Other uses
+		 * of this bounce page may need to store a full page of
+		 * data and/or assume it starts on a page boundary.
+		 */
+		bpage->vaddr &= ~PAGE_MASK;
+		bpage->busaddr &= ~PAGE_MASK;
+	}
 
 	mtx_lock(&bounce_lock);
 	STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);

Modified: head/sys/ia64/ia64/busdma_machdep.c
==============================================================================
--- head/sys/ia64/ia64/busdma_machdep.c	Fri Apr 17 11:30:32 2009	(r191200)
+++ head/sys/ia64/ia64/busdma_machdep.c	Fri Apr 17 13:22:18 2009	(r191201)
@@ -940,9 +940,7 @@ add_bounce_page(bus_dma_tag_t dmat, bus_
 	mtx_unlock(&bounce_lock);
 
 	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
-		/* page offset needs to be preserved */
-		bpage->vaddr &= ~PAGE_MASK;
-		bpage->busaddr &= ~PAGE_MASK;
+		/* Page offset needs to be preserved. */
 		bpage->vaddr |= vaddr & PAGE_MASK;
 		bpage->busaddr |= vaddr & PAGE_MASK;
 	}
@@ -959,6 +957,15 @@ free_bounce_page(bus_dma_tag_t dmat, str
 
 	bpage->datavaddr = 0;
 	bpage->datacount = 0;
+	if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
+		/*
+		 * Reset the bounce page to start at offset 0.  Other uses
+		 * of this bounce page may need to store a full page of
+		 * data and/or assume it starts on a page boundary.
+		 */
+		bpage->vaddr &= ~PAGE_MASK;
+		bpage->busaddr &= ~PAGE_MASK;
+	}
 
 	mtx_lock(&bounce_lock);
 	STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);