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=-7.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 9A0D5C04EB8 for ; Tue, 4 Dec 2018 10:58:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D1102087F for ; Tue, 4 Dec 2018 10:58:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="frFY26S6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D1102087F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S1726872AbeLDK6B (ORCPT ); Tue, 4 Dec 2018 05:58:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:42138 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726399AbeLDK56 (ORCPT ); Tue, 4 Dec 2018 05:57:58 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1E75B2146D; Tue, 4 Dec 2018 10:57:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543921077; bh=KLpEduOzAl3nj66wSdpt225swj/rHbcTo6LZwEXecmU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=frFY26S6kJwQZoYoxFyJKOcfW6mV+X6UCWicgOgZ+GfRAj85fhDI6WcgaTNJ1fM2e uhVSNfnlCgOI2Iakz4z9XfNTUzioF8aBZfD899w47Xw4zaAUF1mFgcoEYaA0lpeumJ 2302z7OFAZ9fojJuSaZlIbL5K86jounuOTlf/AqI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Max Filippov Subject: [PATCH 4.19 070/139] xtensa: enable coprocessors that are being flushed Date: Tue, 4 Dec 2018 11:49:11 +0100 Message-Id: <20181204103652.945763798@linuxfoundation.org> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181204103649.950154335@linuxfoundation.org> References: <20181204103649.950154335@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Max Filippov commit 2958b66694e018c552be0b60521fec27e8d12988 upstream. coprocessor_flush_all may be called from a context of a thread that is different from the thread being flushed. In that case contents of the cpenable special register may not match ti->cpenable of the target thread, resulting in unhandled coprocessor exception in the kernel context. Set cpenable special register to the ti->cpenable of the target register for the duration of the flush and restore it afterwards. This fixes the following crash caused by coprocessor register inspection in native gdb: (gdb) p/x $w0 Illegal instruction in kernel: sig: 9 [#1] PREEMPT Call Trace: ___might_sleep+0x184/0x1a4 __might_sleep+0x41/0xac exit_signals+0x14/0x218 do_exit+0xc9/0x8b8 die+0x99/0xa0 do_illegal_instruction+0x18/0x6c common_exception+0x77/0x77 coprocessor_flush+0x16/0x3c arch_ptrace+0x46c/0x674 sys_ptrace+0x2ce/0x3b4 system_call+0x54/0x80 common_exception+0x77/0x77 note: gdb[100] exited with preempt_count 1 Killed Cc: stable@vger.kernel.org Signed-off-by: Max Filippov Signed-off-by: Greg Kroah-Hartman --- arch/xtensa/kernel/process.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -94,18 +94,21 @@ void coprocessor_release_all(struct thre void coprocessor_flush_all(struct thread_info *ti) { - unsigned long cpenable; + unsigned long cpenable, old_cpenable; int i; preempt_disable(); + RSR_CPENABLE(old_cpenable); cpenable = ti->cpenable; + WSR_CPENABLE(cpenable); for (i = 0; i < XCHAL_CP_MAX; i++) { if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti) coprocessor_flush(ti, i); cpenable >>= 1; } + WSR_CPENABLE(old_cpenable); preempt_enable(); }