svn commit: r206405 - head/sys/mips/mips

[Nathan Whitehorn]

Author: nwhitehorn
Date: Fri Apr  9 01:14:11 2010
New Revision: 206405
URL: http://svn.freebsd.org/changeset/base/206405

Log:
  Fix a bug where bus_dma_load_xxx() would not bounce misaligned buffers
  due to rounding the buffer's physical address to the beginning of its
  page. This fixes a panic in arge(4) when using PPPoE.
  
  Reported by:	Jakob van Santen <vansanten at wisc dot edu>
  Reviewed by:	gonzo
  Obtained from:	amd64

Modified:
  head/sys/mips/mips/busdma_machdep.c

Modified: head/sys/mips/mips/busdma_machdep.c
==============================================================================
--- head/sys/mips/mips/busdma_machdep.c	Thu Apr  8 19:34:55 2010	(r206404)
+++ head/sys/mips/mips/busdma_machdep.c	Fri Apr  9 01:14:11 2010	(r206405)
@@ -687,16 +687,21 @@ _bus_dmamap_count_pages(bus_dma_tag_t dm
 		 * Count the number of bounce pages
 		 * needed in order to complete this transfer
 		 */
-		vaddr = trunc_page((vm_offset_t)buf);
+		vaddr = (vm_offset_t)buf;
 		vendaddr = (vm_offset_t)buf + buflen;
 
 		while (vaddr < vendaddr) {
+			bus_size_t sg_len;
+
 			KASSERT(kernel_pmap == pmap, ("pmap is not kernel pmap"));
+			sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
 			paddr = pmap_kextract(vaddr);
 			if (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
-			    run_filter(dmat, paddr) != 0)
+			    run_filter(dmat, paddr) != 0) {
+				sg_len = roundup2(sg_len, dmat->alignment);
 				map->pagesneeded++;
-			vaddr += PAGE_SIZE;
+			}
+			vaddr += sg_len;
 		}
 		CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 	}