From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54275C18DF5 for ; Tue, 13 Nov 2018 20:25:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 225B32245E for ; Tue, 13 Nov 2018 20:25:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 225B32245E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=vmware.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731073AbeKNGZ3 (ORCPT ); Wed, 14 Nov 2018 01:25:29 -0500 Received: from ex13-edg-ou-002.vmware.com ([208.91.0.190]:45045 "EHLO EX13-EDG-OU-002.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728686AbeKNGZ2 (ORCPT ); Wed, 14 Nov 2018 01:25:28 -0500 Received: from sc9-mailhost2.vmware.com (10.113.161.72) by EX13-EDG-OU-002.vmware.com (10.113.208.156) with Microsoft SMTP Server id 15.0.1156.6; Tue, 13 Nov 2018 12:25:16 -0800 Received: from sc2-haas01-esx0118.eng.vmware.com (sc2-haas01-esx0118.eng.vmware.com [10.172.44.118]) by sc9-mailhost2.vmware.com (Postfix) with ESMTP id 9C7EBB1A4D; Tue, 13 Nov 2018 15:25:38 -0500 (EST) From: Nadav Amit To: Ingo Molnar CC: , , "H. Peter Anvin" , Thomas Gleixner , Borislav Petkov , Dave Hansen , Peter Zijlstra , , , , Nadav Amit , Andy Lutomirski , Kees Cook , Dave Hansen Subject: [PATCH v5 04/10] fork: provide a function for copying init_mm Date: Tue, 13 Nov 2018 05:07:24 -0800 Message-ID: <20181113130730.44844-5-namit@vmware.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181113130730.44844-1-namit@vmware.com> References: <20181113130730.44844-1-namit@vmware.com> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: None (EX13-EDG-OU-002.vmware.com: namit@vmware.com does not designate permitted sender hosts) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Provide a function for copying init_mm. This function will be later used for setting a temporary mm. Cc: Andy Lutomirski Cc: Kees Cook Cc: Peter Zijlstra Cc: Dave Hansen Reviewed-by: Masami Hiramatsu Tested-by: Masami Hiramatsu Signed-off-by: Nadav Amit --- include/linux/sched/task.h | 1 + kernel/fork.c | 24 ++++++++++++++++++------ 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index 108ede99e533..ac0a675678f5 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -74,6 +74,7 @@ extern void exit_itimers(struct signal_struct *); extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long); extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *); struct task_struct *fork_idle(int); +struct mm_struct *copy_init_mm(void); extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); diff --git a/kernel/fork.c b/kernel/fork.c index 07cddff89c7b..01d3f5b39363 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1297,13 +1297,20 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm) complete_vfork_done(tsk); } -/* - * Allocate a new mm structure and copy contents from the - * mm structure of the passed in task structure. +/** + * dup_mm() - duplicates an existing mm structure + * @tsk: the task_struct with which the new mm will be associated. + * @oldmm: the mm to duplicate. + * + * Allocates a new mm structure and copy contents from the provided + * @oldmm structure. + * + * Return: the duplicated mm or NULL on failure. */ -static struct mm_struct *dup_mm(struct task_struct *tsk) +static struct mm_struct *dup_mm(struct task_struct *tsk, + struct mm_struct *oldmm) { - struct mm_struct *mm, *oldmm = current->mm; + struct mm_struct *mm; int err; mm = allocate_mm(); @@ -1370,7 +1377,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) } retval = -ENOMEM; - mm = dup_mm(tsk); + mm = dup_mm(tsk, current->mm); if (!mm) goto fail_nomem; @@ -2176,6 +2183,11 @@ struct task_struct *fork_idle(int cpu) return task; } +struct mm_struct *copy_init_mm(void) +{ + return dup_mm(NULL, &init_mm); +} + /* * Ok, this is the main fork-routine. * -- 2.17.1