x86: pgtable, document pde bits

Some of pde bits weren't documented, add the short description to them.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 7 deletions

diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 2ce765070464..f1d9f4a03f6f 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -4,13 +4,13 @@
 #define USER_PTRS_PER_PGD       ((TASK_SIZE-1)/PGDIR_SIZE+1)
 #define FIRST_USER_ADDRESS      0
 
-#define _PAGE_BIT_PRESENT       0
-#define _PAGE_BIT_RW            1
-#define _PAGE_BIT_USER          2
-#define _PAGE_BIT_PWT           3
-#define _PAGE_BIT_PCD           4
-#define _PAGE_BIT_ACCESSED      5
-#define _PAGE_BIT_DIRTY         6
+#define _PAGE_BIT_PRESENT       0       /* is present */
+#define _PAGE_BIT_RW            1       /* writeable */
+#define _PAGE_BIT_USER          2       /* userspace addressable */
+#define _PAGE_BIT_PWT           3       /* page write through */
+#define _PAGE_BIT_PCD           4       /* page cache disabled */
+#define _PAGE_BIT_ACCESSED      5       /* was accessed (raised by CPU) */
+#define _PAGE_BIT_DIRTY         6       /* was written to (raised by CPU) */
 #define _PAGE_BIT_FILE          6
 #define _PAGE_BIT_PSE           7       /* 4 MB (or 2MB) page */
 #define _PAGE_BIT_PAT           7       /* on 4KB pages */