Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756035Ab2F1M6t (ORCPT ); Thu, 28 Jun 2012 08:58:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45402 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755948Ab2F1M6m (ORCPT ); Thu, 28 Jun 2012 08:58:42 -0400 From: Andrea Arcangeli To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Hillf Danton , Dan Smith , Peter Zijlstra , Linus Torvalds , Andrew Morton , Thomas Gleixner , Ingo Molnar , Paul Turner , Suresh Siddha , Mike Galbraith , "Paul E. McKenney" , Lai Jiangshan , Bharata B Rao , Lee Schermerhorn , Rik van Riel , Johannes Weiner , Srivatsa Vaddagiri , Christoph Lameter , Alex Shi , Mauricio Faria de Oliveira , Konrad Rzeszutek Wilk , Don Morris , Benjamin Herrenschmidt Subject: [PATCH 04/40] xen: document Xen is using an unused bit for the pagetables Date: Thu, 28 Jun 2012 14:55:44 +0200 Message-Id: <1340888180-15355-5-git-send-email-aarcange@redhat.com> In-Reply-To: <1340888180-15355-1-git-send-email-aarcange@redhat.com> References: <1340888180-15355-1-git-send-email-aarcange@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2100 Lines: 50 Xen has taken over the last reserved bit available for the pagetables which is set through ioremap, this documents it and makes the code more readable. Signed-off-by: Andrea Arcangeli --- arch/x86/include/asm/pgtable_types.h | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 013286a..b74cac9 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -17,7 +17,7 @@ #define _PAGE_BIT_PAT 7 /* on 4KB pages */ #define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */ #define _PAGE_BIT_UNUSED1 9 /* available for programmer */ -#define _PAGE_BIT_IOMAP 10 /* flag used to indicate IO mapping */ +#define _PAGE_BIT_UNUSED2 10 #define _PAGE_BIT_HIDDEN 11 /* hidden by kmemcheck */ #define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */ #define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1 @@ -41,7 +41,7 @@ #define _PAGE_PSE (_AT(pteval_t, 1) << _PAGE_BIT_PSE) #define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL) #define _PAGE_UNUSED1 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1) -#define _PAGE_IOMAP (_AT(pteval_t, 1) << _PAGE_BIT_IOMAP) +#define _PAGE_UNUSED2 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED2) #define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT) #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE) #define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL) @@ -49,6 +49,13 @@ #define _PAGE_SPLITTING (_AT(pteval_t, 1) << _PAGE_BIT_SPLITTING) #define __HAVE_ARCH_PTE_SPECIAL +/* flag used to indicate IO mapping */ +#ifdef CONFIG_XEN +#define _PAGE_IOMAP (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED2) +#else +#define _PAGE_IOMAP (_AT(pteval_t, 0)) +#endif + #ifdef CONFIG_KMEMCHECK #define _PAGE_HIDDEN (_AT(pteval_t, 1) << _PAGE_BIT_HIDDEN) #else -- 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/