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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 C095EC47247 for ; Sat, 9 May 2020 17:37:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A39620A8B for ; Sat, 9 May 2020 17:37:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589045844; bh=q0R70uyPyClzQN46UcwhEYpcP3Otr2K5sbFabZXwPkM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=cwCunWk1bhB4P12LeYXo6TR7QMEBmwAzoy78M1v966JAKq3iOODg4Wuoqck5v6eB+ Zwt0QzlThHJN4wkddmG2BN/kyj7pZUSioVOuBvlbqEvybVVwT6HJxAyYsX92/q8VmZ zWYnHyjk2ywusUpwra3mZBtZeXpdm/8lCveCVADg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728651AbgEIRhX (ORCPT ); Sat, 9 May 2020 13:37:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:54656 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728595AbgEIRhS (ORCPT ); Sat, 9 May 2020 13:37:18 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 046B824975; Sat, 9 May 2020 17:37:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589045838; bh=q0R70uyPyClzQN46UcwhEYpcP3Otr2K5sbFabZXwPkM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n94VuA8AX3L3p5UCKZiqr8kkkk5JyoqQQ5JjA/RqhkEFZse3fTcSDZlwn8XivQVb+ nR15R5NB6x8x9yYa/2IrXN+ybdi2FUjwHF+ikw1hzbE7unwL8EjeeoVxdPEbGajzk0 nyGStYKuTV4XlMtj96AztzuOCTb6dCKJKsAn9NNw= From: Sasha Levin To: linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de, luto@kernel.org Cc: hpa@zytor.com, dave.hansen@intel.com, tony.luck@intel.com, ak@linux.intel.com, ravi.v.shankar@intel.com, chang.seok.bae@intel.com, Sasha Levin Subject: [PATCH v11 13/18] x86/fsgsbase/64: Use FSGSBASE instructions on thread copy and ptrace Date: Sat, 9 May 2020 13:36:50 -0400 Message-Id: <20200509173655.13977-14-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200509173655.13977-1-sashal@kernel.org> References: <20200509173655.13977-1-sashal@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Chang S. Bae" When FSGSBASE is enabled, copying threads and reading FS/GS base using ptrace must read the actual values. When copying a thread, use fsgs_save() and copy the saved values. For ptrace, the bases must be read from memory regardless of the selector if FSGSBASE is enabled. Suggested-by: Andy Lutomirski Signed-off-by: Chang S. Bae Signed-off-by: Sasha Levin Reviewed-by: Tony Luck Cc: Thomas Gleixner Cc: Borislav Petkov Cc: Andy Lutomirski Cc: H. Peter Anvin Cc: Dave Hansen Cc: Tony Luck Cc: Andi Kleen --- arch/x86/kernel/process.c | 10 ++++++---- arch/x86/kernel/process_64.c | 6 ++++-- 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 9da70b279dad8..3ebb56cc2cfee 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -127,6 +127,7 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, struct inactive_task_frame *frame; struct fork_frame *fork_frame; struct pt_regs *childregs; + struct task_struct *me = current; int ret = 0; childregs = task_pt_regs(p); @@ -140,10 +141,11 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); #ifdef CONFIG_X86_64 - savesegment(gs, p->thread.gsindex); - p->thread.gsbase = p->thread.gsindex ? 0 : current->thread.gsbase; - savesegment(fs, p->thread.fsindex); - p->thread.fsbase = p->thread.fsindex ? 0 : current->thread.fsbase; + save_fsgs(me); + p->thread.fsindex = me->thread.fsindex; + p->thread.fsbase = me->thread.fsbase; + p->thread.gsindex = me->thread.gsindex; + p->thread.gsbase = me->thread.gsbase; savesegment(es, p->thread.es); savesegment(ds, p->thread.ds); #else diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 4be88124d81ea..57cdbbb0381ac 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -346,7 +346,8 @@ unsigned long x86_fsbase_read_task(struct task_struct *task) if (task == current) fsbase = x86_fsbase_read_cpu(); - else if (task->thread.fsindex == 0) + else if (static_cpu_has(X86_FEATURE_FSGSBASE) || + (task->thread.fsindex == 0)) fsbase = task->thread.fsbase; else fsbase = x86_fsgsbase_read_task(task, task->thread.fsindex); @@ -360,7 +361,8 @@ unsigned long x86_gsbase_read_task(struct task_struct *task) if (task == current) gsbase = x86_gsbase_read_cpu_inactive(); - else if (task->thread.gsindex == 0) + else if (static_cpu_has(X86_FEATURE_FSGSBASE) || + (task->thread.gsindex == 0)) gsbase = task->thread.gsbase; else gsbase = x86_fsgsbase_read_task(task, task->thread.gsindex); -- 2.20.1