Enhance pmap_mapdev_attr(). Take advantage of recent enhancements to

pmap_change_attr() in order to use the direct map for any cache mode, not
just write-back mode.

It is worth noting that this change also eliminates a situation in which we
have two mappings to the same physical memory with different cache modes.

Submitted by:	Magesh Dhasayyan (with some changes by me)
Discussed with:	jhb

1 files changed, 7 insertions, 4 deletions

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 4d18f40..cc40152 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -4305,11 +4305,14 @@ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, int mode)
 	vm_offset_t va, tmpva, offset;
 
 	/*
-	 * If this fits within the direct map window and use WB caching
-	 * mode, use the direct map.
+	 * If the specified range of physical addresses fits within the direct
+	 * map window, use the direct map. 
 	 */
-	if (pa < dmaplimit && (pa + size) < dmaplimit && mode == PAT_WRITE_BACK)
-		return ((void *)PHYS_TO_DMAP(pa));
+	if (pa < dmaplimit && pa + size < dmaplimit) {
+		va = PHYS_TO_DMAP(pa);
+		if (!pmap_change_attr(va, size, mode))
+			return ((void *)va);
+	}
 	offset = pa & PAGE_MASK;
 	size = roundup(offset + size, PAGE_SIZE);
 	va = kmem_alloc_nofault(kernel_map, size);