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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 6701BC433E1 for ; Mon, 24 Aug 2020 07:19:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4755E20767 for ; Mon, 24 Aug 2020 07:19:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726119AbgHXHTv (ORCPT ); Mon, 24 Aug 2020 03:19:51 -0400 Received: from mail-io1-f67.google.com ([209.85.166.67]:40459 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725924AbgHXHTs (ORCPT ); Mon, 24 Aug 2020 03:19:48 -0400 Received: by mail-io1-f67.google.com with SMTP id t187so6205349iod.7 for ; Mon, 24 Aug 2020 00:19:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HSoxBqiatdKGA4ArfaKuWypHDOvLL4zqqw0BsxbCWVI=; b=sAH0U+Inc7okk3vEgv2VUEb3M/e9G1j2esTib6oXbjS17YTY6QEtBCm8PeHMIBrJBY TmKRlyw9Kzz6LngK7v3hueYhW4DmFXaJHB4TCYMbHiD7DMXv+hrtOLyZiIWKdFYVIGrt 8WGnHHPJIgxQzyVlA9GkS3vF1Zv1yG4qoxF9WZgYeadFGcSUe0yWbE/lT6HyTA5TBm2o pGT+A05mXnsZzZ/WR4WYArQoHU6CXJNwXgXiCbJcbfCsiZIloRembdTSvMjcvJJ3VRdJ jJjb43S1AFgewsSwOfJvZiONdTzn9PRFDbowzhq7eRzreFD6xIvjHvtPsDFzEY0AO4Y2 8MVA== X-Gm-Message-State: AOAM531QzzC+CAFE1dEWjyH8AgiljKLclqpUrCmcIO/R03MH0FViNcD2 0cc6bT7Hsp+mFqL9LqMIzEBDdLW1Cn4ghB+Wf0USz21in8WCePGN X-Google-Smtp-Source: ABdhPJxz/cye2z3iecDqGwiqhVqiP4GEImPS66IZYEIpYoA//wyRRkQSf2hCesJscOFT3kMkeBo5ulk4kaQV9wwpo+o= X-Received: by 2002:a02:950e:: with SMTP id y14mr4434515jah.106.1598253587635; Mon, 24 Aug 2020 00:19:47 -0700 (PDT) MIME-Version: 1.0 References: <20200821072329.18006-1-huangpei@loongson.cn> In-Reply-To: <20200821072329.18006-1-huangpei@loongson.cn> From: Huacai Chen Date: Mon, 24 Aug 2020 15:19:36 +0800 Message-ID: Subject: Re: [PATCH 1/3] MIPS: add missing MSACSR and upper MSA initialization To: Huang Pei Cc: Thomas Bogendoerfer , Paul Ambrose , Li Xuefeng , Yang Tiezhu , Gao Juxin , Fuxin Zhang , "open list:MIPS" Content-Type: text/plain; charset="UTF-8" Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Hi, Pei, On Fri, Aug 21, 2020 at 3:26 PM Huang Pei wrote: > > own_fp_inatomic() does not restore/initialize MSACSR and upper MSA regs, so > MSACSR and MSA upper regs's value from previous task on current cpu can leak > into current task and cause unpredictable behavior when MSA context not > initialized. > > Signed-off-by: Huang Pei > --- > arch/mips/kernel/traps.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c > index 38aa07ccdbcc..99a8f1b7b522 100644 > --- a/arch/mips/kernel/traps.c > +++ b/arch/mips/kernel/traps.c > @@ -1287,6 +1287,8 @@ static int enable_restore_fp_context(int msa) > err = own_fpu_inatomic(1); > if (msa && !err) { > enable_msa(); > + write_msa_csr(current->thread.fpu.msacsr); > + init_msa_upper(); I think write_msa_csr(current->thread.fpu.msacsr) is needed here, but I don't know whether init_msa_upper() is also needed. Maybe you should investegate cc97ab235f3fe32401ca198cebe6f42642e9 ("MIPS: Simplify FP context initialization") which removes init_msa_upper(). Huacai > set_thread_flag(TIF_USEDMSA); > set_thread_flag(TIF_MSA_CTX_LIVE); > } > -- > 2.17.1 >