Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423165AbXBUVYH (ORCPT ); Wed, 21 Feb 2007 16:24:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423144AbXBUVYD (ORCPT ); Wed, 21 Feb 2007 16:24:03 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:40367 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423150AbXBUVUw (ORCPT ); Wed, 21 Feb 2007 16:20:52 -0500 Date: Wed, 21 Feb 2007 22:15:37 +0100 From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Arjan van de Ven , Christoph Hellwig , Andrew Morton , Alan Cox , Ulrich Drepper , Zach Brown , Evgeniy Polyakov , "David S. Miller" , Suparna Bhattacharya , Davide Libenzi , Jens Axboe , Thomas Gleixner Subject: [patch 08/13] syslets: x86, add move_user_context() method Message-ID: <20070221211537.GH7579@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070221211355.GA7302@elte.hu> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -5.3 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-5.3 required=5.9 tests=ALL_TRUSTED,BAYES_00 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2463 Lines: 73 From: Ingo Molnar add the move_user_context() method to move the user-space context of one kernel thread to another kernel thread. User-space might notice the changed TID, but execution, stack and register contents (general purpose and FPU) are still the same. An architecture must implement this interface before it can turn CONFIG_ASYNC_SUPPORT on. Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven --- arch/i386/kernel/process.c | 21 +++++++++++++++++++++ include/asm-i386/system.h | 7 +++++++ 2 files changed, 28 insertions(+) Index: linux/arch/i386/kernel/process.c =================================================================== --- linux.orig/arch/i386/kernel/process.c +++ linux/arch/i386/kernel/process.c @@ -820,6 +820,27 @@ unsigned long get_wchan(struct task_stru } /* + * Move user-space context from one kernel thread to another. + * This includes registers and FPU state. Callers must make + * sure that neither task is running user context at the moment: + */ +void +move_user_context(struct task_struct *new_task, struct task_struct *old_task) +{ + struct pt_regs *old_regs = task_pt_regs(old_task); + struct pt_regs *new_regs = task_pt_regs(new_task); + union i387_union *tmp; + + *new_regs = *old_regs; + /* + * Flip around the FPU state too: + */ + tmp = new_task->thread.i387; + new_task->thread.i387 = old_task->thread.i387; + old_task->thread.i387 = tmp; +} + +/* * sys_alloc_thread_area: get a yet unused TLS descriptor index. */ static int get_free_idx(void) Index: linux/include/asm-i386/system.h =================================================================== --- linux.orig/include/asm-i386/system.h +++ linux/include/asm-i386/system.h @@ -33,6 +33,13 @@ extern struct task_struct * FASTCALL(__s "2" (prev), "d" (next)); \ } while (0) +/* + * Move user-space context from one kernel thread to another. + * This includes registers and FPU state for now: + */ +extern void +move_user_context(struct task_struct *new_task, struct task_struct *old_task); + #define _set_base(addr,base) do { unsigned long __pr; \ __asm__ __volatile__ ("movw %%dx,%1\n\t" \ "rorl $16,%%edx\n\t" \ - 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/