Changeset 186b919 in mainline

Timestamp:

2013-08-04T10:30:54Z (11 years ago)

Author:

Jan Vesely <jano.vesely@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

8abcf4e

Parents:

67d02bb

Message:

armv6+: Add explanatory comments to paging attributes.

File:

• kernel/arch/arm32/include/arch/mm/page_armv6.h (modified) (1 diff)

kernel/arch/arm32/include/arch/mm/page_armv6.h

@@ -233 +233 @@
                         p->descriptor_type = PTE_DESCRIPTOR_SMALL_PAGE_NX;
         }
-        
-        /* tex=0 buf=1 and cache=1 => normal memory
-         * tex=0 buf=1 and cache=0 => shareable device mmio
-         */
 
         if (flags & PAGE_CACHEABLE) {
+                /*
+                 * Write-back, write-allocate memory, see ch. B3.8.2
+                 * (p. B3-1358) of ARM Architecture reference manual.
+                 */
                 p->tex = 1;
                 p->cacheable = 1;
+                p->bufferable = 1;
         } else {
+                /*
+                 * Shareable device memory, see ch. B3.8.2 (p. B3-1358) of
+                 * ARM Architecture reference manual.
+                 */
                 p->tex = 0;
                 p->cacheable = 0;
+                p->bufferable = 1;
         }
-        p->bufferable = 1;
         
         /* Shareable is ignored for devices (non-cacheable),
-         * turn it on for normal memory. */
+         * turn it off for normal memory. */
         p->shareable = 0;