Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261458AbTIXDaN (ORCPT ); Tue, 23 Sep 2003 23:30:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261585AbTIXD3o (ORCPT ); Tue, 23 Sep 2003 23:29:44 -0400 Received: from dp.samba.org ([66.70.73.150]:12236 "EHLO lists.samba.org") by vger.kernel.org with ESMTP id S261628AbTIXD3Z (ORCPT ); Tue, 23 Sep 2003 23:29:25 -0400 From: Rusty Trivial Russell To: Linus Torvalds Cc: linux-kernel@vger.kernel.org Subject: [TRIVIAL] Re: document unused pte bits on i386 Date: Wed, 24 Sep 2003 12:52:53 +1000 Message-Id: <20030924032924.B3AEB2C491@lists.samba.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2147 Lines: 50 From: Ed L Cashin Ed L Cashin writes: > 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. For consistency, there should be the analogous _PAGE_BIT_XXX macros, too, so here's a replacement patch that has those. --- trivial-2.6.0-test5-bk10/include/asm-i386/pgtable.h.orig 2003-09-24 12:27:18.000000000 +1000 +++ trivial-2.6.0-test5-bk10/include/asm-i386/pgtable.h 2003-09-24 12:27:18.000000000 +1000 @@ -108,6 +108,9 @@ #define _PAGE_BIT_DIRTY 6 #define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page, Pentium+, if present.. */ #define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */ +#define _PAGE_BIT_UNUSED1 9 /* available for programmer */ +#define _PAGE_BIT_UNUSED2 10 +#define _PAGE_BIT_UNUSED3 11 #define _PAGE_PRESENT 0x001 #define _PAGE_RW 0x002 @@ -118,6 +121,9 @@ #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 */ -- What is this? http://www.kernel.org/pub/linux/kernel/people/rusty/trivial/ Don't blame me: the Monkey is driving File: Ed L Cashin : Re: [TRIVIAL][PATCH] document unused pte bits on i386 - 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/