Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270365AbTHGPwN (ORCPT ); Thu, 7 Aug 2003 11:52:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270322AbTHGPtN (ORCPT ); Thu, 7 Aug 2003 11:49:13 -0400 Received: from marblerye.cs.uga.edu ([128.192.101.172]:27011 "HELO marblerye.cs.uga.edu") by vger.kernel.org with SMTP id S270237AbTHGPqs (ORCPT ); Thu, 7 Aug 2003 11:46:48 -0400 To: linux-kernel Cc: trivial Subject: Re: [TRIVIAL][PATCH] document unused pte bits on i386 References: <87n0elwky1.fsf@uga.edu> From: Ed L Cashin Date: Thu, 07 Aug 2003 11:46:47 -0400 Message-ID: <877k5pwjvc.fsf@uga.edu> User-Agent: Gnus/5.090014 (Oort Gnus v0.14) Emacs/21.2 (i386-debian-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1930 Lines: 49 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. --- 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 11:38:17 2003 @@ -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 */ -- --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/