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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 F1D49C433E0 for ; Thu, 28 May 2020 20:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2CA8207D3 for ; Thu, 28 May 2020 20:14:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590696891; bh=Cbug4Zw6pLdPJMyM6ewVPi8za9fxR3JM1cojC9EnM+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=spG/HZj2B278uod1wLZTM7ww8x9EiBsdLu/KMuIMvN95z6H8uhh2+NHjgT1ecYnq6 axBmTq4i8jre5MJfm9Rz1pyLgck9q7ivrzTebrk8XgQjIw8Zn39IHfkAFpsGClvMCJ AnMMJuCiGPymgeLTJtNwvVvmxKNSfpE9KT1mQZ1Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407070AbgE1UOu (ORCPT ); Thu, 28 May 2020 16:14:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:41870 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2407019AbgE1UO0 (ORCPT ); Thu, 28 May 2020 16:14:26 -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 EE06E2088E; Thu, 28 May 2020 20:14:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590696865; bh=Cbug4Zw6pLdPJMyM6ewVPi8za9fxR3JM1cojC9EnM+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k4AEdmZm0JNgL/s0oKV0nM8NQEtvV6FVP+zpgtOHyGsyffMn6AxwzOQXx0Qhl5raN rQdeD3rlf9SHPYNeGSHLlkQLrUSO5SQaJKvouupTtButX4L8jUewo3SCzNZMTMx2eJ a+dSGyhGVU/1cRPAohlORhLGnA1RlgocBEFGsmEs= From: Sasha Levin To: tglx@linutronix.de, luto@kernel.org, ak@linux.intel.com Cc: corbet@lwn.net, mingo@redhat.com, bp@alien8.de, x86@kernel.org, shuah@kernel.org, gregkh@linuxfoundation.org, tony.luck@intel.com, chang.seok.bae@intel.com, dave.hansen@linux.intel.com, peterz@infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, jarkko.sakkinen@linux.intel.com, "H . Peter Anvin" , Ravi Shankar , Sasha Levin Subject: [PATCH v13 07/16] x86/process/64: Use FSGSBASE instructions on thread copy and ptrace Date: Thu, 28 May 2020 16:13:53 -0400 Message-Id: <20200528201402.1708239-8-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200528201402.1708239-1-sashal@kernel.org> References: <20200528201402.1708239-1-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 fsbase and gsbase using ptrace must read the actual values. When copying a thread, use save_fsgs() and copy the saved values. For ptrace, the bases must be read from memory regardless of the selector if FSGSBASE is enabled. [ tglx: Invoke __rdgsbase_inactive() with interrupts disabled ] [ luto: Massage changelog ] Suggested-by: Andy Lutomirski Signed-off-by: Chang S. Bae Signed-off-by: Thomas Gleixner Cc: "H . Peter Anvin" Cc: Andi Kleen Cc: Ravi Shankar Cc: H. Peter Anvin Link: https://lkml.kernel.org/r/1557309753-24073-9-git-send-email-chang.seok.bae@intel.com Signed-off-by: Sasha Levin --- 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 9da70b279dad..0264d9bb8991 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -140,10 +140,12 @@ 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; + current_save_fsgs(); + p->thread.fsindex = current->thread.fsindex; + p->thread.fsbase = current->thread.fsbase; + p->thread.gsindex = current->thread.gsindex; + p->thread.gsbase = current->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 aefb30bc56bc..0bcb48a1264a 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -423,7 +423,8 @@ 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); @@ -437,7 +438,8 @@ 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); -- 2.25.1