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>
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 2ce7650..f1d9f4a 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 */