From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262170AbVHFA2f (ORCPT ); Fri, 5 Aug 2005 20:28:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262122AbVHFA2e (ORCPT ); Fri, 5 Aug 2005 20:28:34 -0400 Received: from mailout1.vmware.com ([65.113.40.130]:37137 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S262170AbVHFA2V (ORCPT ); Fri, 5 Aug 2005 20:28:21 -0400 Date: Fri, 5 Aug 2005 17:26:06 -0700 From: zach@vmware.com Message-Id: <200508060026.j760Q6FT025108@zach-dev.vmware.com> To: akpm@osdl.org, chrisl@vmware.com, davej@codemonkey.org.uk, hpa@zytor.com, linux-kernel@vger.kernel.org, pavel@suse.cz, pratap@vmware.com, Riley@Williams.Name, zach@vmware.com Subject: [PATCH 1/1] i386 Encapsulate copying of pgd entries X-OriginalArrivalTime: 06 Aug 2005 00:27:08.0702 (UTC) FILETIME=[948E73E0:01C59A1D] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Add a clone operation for pgd updates. This helps complete the encapsulation of updates to page tables (or pages about to become page tables) into accessor functions rather than using memcpy() to duplicate them. This is both generally good for consistency and also necessary for running in a hypervisor which requires explicit updates to page table entries. The new function is: clone_pgd_range(pgd_t *dst, pgd_t *src, int count); dst - pointer to pgd range anwhere on a pgd page src - "" count - the number of pgds to copy. dst and src can be on the same page, but the range must not overlap and must not cross a page boundary. Note that I ommitted using this call to copy pgd entries into the software suspend page root, since this is not technically a live paging structure, rather it is used on resume from suspend. CC'ing Pavel in case he has any feedback on this. Signed-off-by: Zachary Amsden Index: linux-2.6.13/arch/i386/mm/pgtable.c =================================================================== --- linux-2.6.13.orig/arch/i386/mm/pgtable.c 2005-08-04 12:02:10.000000000 -0700 +++ linux-2.6.13/arch/i386/mm/pgtable.c 2005-08-05 17:13:29.000000000 -0700 @@ -207,19 +207,18 @@ { unsigned long flags; + memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t)); if (PTRS_PER_PMD == 1) spin_lock_irqsave(&pgd_lock, flags); - memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD, + clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD, swapper_pg_dir + USER_PTRS_PER_PGD, - (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); - + KERNEL_PGD_PTRS); if (PTRS_PER_PMD > 1) return; pgd_list_add(pgd); spin_unlock_irqrestore(&pgd_lock, flags); - memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t)); } /* never called when PTRS_PER_PMD > 1 */ Index: linux-2.6.13/arch/i386/kernel/smpboot.c =================================================================== --- linux-2.6.13.orig/arch/i386/kernel/smpboot.c 2005-08-04 12:02:10.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/smpboot.c 2005-08-04 13:15:45.000000000 -0700 @@ -1017,8 +1017,8 @@ tsc_sync_disabled = 1; /* init low mem mapping */ - memcpy(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS, - sizeof(swapper_pg_dir[0]) * KERNEL_PGD_PTRS); + clone_pgd_range(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS, + KERNEL_PGD_PTRS); flush_tlb_all(); schedule_work(&task); wait_for_completion(&done); Index: linux-2.6.13/include/asm-i386/pgtable.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/pgtable.h 2005-08-04 12:02:10.000000000 -0700 +++ linux-2.6.13/include/asm-i386/pgtable.h 2005-08-05 17:12:33.000000000 -0700 @@ -276,6 +276,21 @@ } /* + * clone_pgd_range(pgd_t *dst, pgd_t *src, int count); + * + * dst - pointer to pgd range anwhere on a pgd page + * src - "" + * count - the number of pgds to copy. + * + * dst and src can be on the same page, but the range must not overlap, + * and must not cross a page boundary. + */ +static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count) +{ + memcpy(dst, src, count * sizeof(pgd_t)); +} + +/* * Macro to mark a page protection value as "uncacheable". On processors which do not support * it, this is a no-op. */