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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3B5EFC433DF for ; Mon, 25 May 2020 08:43:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 259A3206C3 for ; Mon, 25 May 2020 08:43:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389183AbgEYInZ (ORCPT ); Mon, 25 May 2020 04:43:25 -0400 Received: from elvis.franken.de ([193.175.24.41]:38038 "EHLO elvis.franken.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388465AbgEYInZ (ORCPT ); Mon, 25 May 2020 04:43:25 -0400 Received: from uucp (helo=alpha) by elvis.franken.de with local-bsmtp (Exim 3.36 #1) id 1jd8hc-0005hs-00; Mon, 25 May 2020 10:43:20 +0200 Received: by alpha.franken.de (Postfix, from userid 1000) id 9337CC01DC; Mon, 25 May 2020 10:42:34 +0200 (CEST) Date: Mon, 25 May 2020 10:42:34 +0200 From: Thomas Bogendoerfer To: YuanJunQing Cc: paulburton@kernel.org, chenhc@lemote.com, linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, liulichao@loongson.cn Subject: Re: [PATCH] MIPS: Fix IRQ tracing when call handle_fpe() Message-ID: <20200525084234.GA5057@alpha.franken.de> References: <20200525033123.13114-1-yuanjunqing66@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200525033123.13114-1-yuanjunqing66@163.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 25, 2020 at 11:31:23AM +0800, YuanJunQing wrote: > Register "a1" is unsaved in this function, > when CONFIG_TRACE_IRQFLAGS is enabled, > the TRACE_IRQS_OFF macro will call trace_hardirqs_off(), > and this may change register "a1". > The variment of register "a1" may send SIGFPE signal > to task when call do_fpe(),and this may kill the task. > > Signed-off-by: YuanJunQing > --- > arch/mips/kernel/genex.S | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S > index 8236fb291e3f..956a76429773 100644 > --- a/arch/mips/kernel/genex.S > +++ b/arch/mips/kernel/genex.S > @@ -480,16 +480,18 @@ NESTED(nmi_handler, PT_SIZE, sp) > /* gas fails to assemble cfc1 for some archs (octeon).*/ \ > .set mips1 > SET_HARDFLOAT > - cfc1 a1, fcr31 > + cfc1 s0, fcr31 > .set pop > CLI > TRACE_IRQS_OFF > + move a1,s0 > .endm do we realy need to read fcr31 that early ? Wouldn't it work to just move the cfc1 below TRACE_IRQS_OFF ? Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]