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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 46739C43461 for ; Tue, 8 Sep 2020 15:18:02 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CD14B20738 for ; Tue, 8 Sep 2020 15:18:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qXldfjGt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD14B20738 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=nsy4ZXBf/S0+/DPX/O8oMgOB8If71cBhnREt867wbrk=; b=qXldfjGtAEG0va5VF7GixyBCK kos0XHOya4sYAGgjiYJOd6yjuUCqk/h74VlVqVWWmSdTJkLAid+InXiW+NtKIDd8aNtf115vqr5s5 9XcJcCWhnvwK3lLJsNp6dNr5RlA2oBflAqn3cOzXK53IMYZAz5wrnyzQ3bTaOssNnxBfgy3aDYzT4 pdBrTj3/BjEDrkZ7N5/y+Zm4v9G7NhrKMksReWpOleKOWYp3Mh0YJleGb5McbnQKb5/lTQ3BvhE/l Z01diBqQvp0tCmBHdw+L7M8Z2orCWp4shIOGbGHke6Pf8UTCQaHr67ufcEMvUj5iwDAZLIZASbh/0 MRH59Qvdw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFfMH-0000c2-8L; Tue, 08 Sep 2020 15:16:33 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFfMD-0000aM-2M for linux-arm-kernel@lists.infradead.org; Tue, 08 Sep 2020 15:16:30 +0000 Received: from gaia (unknown [46.69.195.48]) (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 98CA822404; Tue, 8 Sep 2020 15:16:25 +0000 (UTC) Date: Tue, 8 Sep 2020 16:16:23 +0100 From: Catalin Marinas To: Andrey Konovalov Subject: Re: [PATCH 24/35] arm64: mte: Switch GCR_EL1 in kernel entry and exit Message-ID: <20200908151622.GJ25591@gaia> References: <20200827103819.GE29264@gaia> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200908_111629_191040_AF226DFA X-CRM114-Status: GOOD ( 17.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Linux ARM , Marco Elver , Elena Petrova , Kevin Brodsky , Will Deacon , Branislav Rankov , kasan-dev , LKML , Linux Memory Management List , Alexander Potapenko , Evgenii Stepanov , Andrey Ryabinin , Andrew Morton , Vincenzo Frascino , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Sep 08, 2020 at 03:58:07PM +0200, Andrey Konovalov wrote: > On Thu, Aug 27, 2020 at 12:38 PM Catalin Marinas > wrote: > > > > On Fri, Aug 14, 2020 at 07:27:06PM +0200, Andrey Konovalov wrote: > > > @@ -957,6 +984,7 @@ SYM_FUNC_START(cpu_switch_to) > > > mov sp, x9 > > > msr sp_el0, x1 > > > ptrauth_keys_install_kernel x1, x8, x9, x10 > > > + mte_restore_gcr 1, x1, x8, x9 > > > scs_save x0, x8 > > > scs_load x1, x8 > > > ret > > > > Since we set GCR_EL1 on exception entry and return, why is this needed? > > We don't have a per-kernel thread GCR_EL1, it's global to all threads, > > so I think cpu_switch_to() should not be touched. > > Dropping this line from the diff leads to many false-positives... I'll > leave this to Vincenzo. I wouldn't expect this to have any effect but maybe the mte_thread_switch() code still touches GCR_EL1 (it does this in the user-space support, Vincenzo's patches should move that to exception entry/return). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel