Hi. This small patch documents that bits 9, 10, and 11 are unused by
the Linux kernel. The IA-32 Intel Architecture Software Developer's
Manual says that these bits are available for programmer use.
I checked and couldn't see any use of these bits in the Linux kernel.
If I'm wrong and these bits *are* being used by the linux kernel, a
comment in include/asm-i386/pgtable.h would be helpful. If they are
not, this patch confirms for developers that the kernel isn't using
these bits.
--- linux-2.6.0-test2/include/asm-i386/pgtable.h~ Sun Jul 27 13:06:27 2003
+++ linux-2.6.0-test2/include/asm-i386/pgtable.h Thu Aug 7 11:16:36 2003
@@ -118,6 +118,9 @@
#define _PAGE_DIRTY 0x040
#define _PAGE_PSE 0x080 /* 4 MB (or 2MB) page, Pentium+, if present.. */
#define _PAGE_GLOBAL 0x100 /* Global TLB entry PPro+ */
+#define _PAGE_UNUSED1 0x200 /* available for programmer */
+#define _PAGE_UNUSED2 0x400
+#define _PAGE_UNUSED3 0x800
#define _PAGE_FILE 0x040 /* set:pagecache unset:swap */
#define _PAGE_PROTNONE 0x080 /* If not present */
-- --Ed L Cashin | PGP public key: ecashin@uga.edu | http://noserose.net/e/pgp/- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Thu Aug 07 2003 - 22:00:38 EST