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=-14.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 394DDC4363E for ; Thu, 8 Apr 2021 17:02:03 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 C043B6113C for ; Thu, 8 Apr 2021 17:02:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C043B6113C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Subject:Cc:To: From:Message-ID:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Z3EsA1cVp0P7Gm+sG8+buJpuZFuuJJZcRqzgRneuFI0=; b=rCEkLg4FM56eEBjFQnJ08bGMQ yfRtYPu+yTMCTHQ7Q1iiVdWWwq+i+/7XT98/2sPZgFec8YY49dVhMlV2HtgUEKlygrZjXNLrcgOwh Q7F434yF/D42I/XwZhD2Hba8TTfyoTGWAAilANWlXA2yKy0zgacBun180XF5QGwioV6JI6fNTmhW+ infC/mRfjK02T1IvnzFziN99PvmEwEZyENSTjeobkF5hh749yzBvrG+wn4htgRl4H5LwJtg7WOQj4 /Np3eDypiQWPiBMrdx1iZvxYoQTbYt5qqiVDWuCqVD+BTNOZ1HogpWsnXZ+n0Kvww7hVPiqBYYjv9 KSx/66+aA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lUY12-008iJj-63; Thu, 08 Apr 2021 17:00:24 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lUY0x-008iID-6P for linux-arm-kernel@lists.infradead.org; Thu, 08 Apr 2021 17:00:20 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (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 9EA26610CC; Thu, 8 Apr 2021 17:00:17 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lUY0t-006MTK-Cu; Thu, 08 Apr 2021 18:00:15 +0100 Date: Thu, 08 Apr 2021 18:00:14 +0100 Message-ID: <87tuogogo1.wl-maz@kernel.org> From: Marc Zyngier To: Mark Brown Cc: Catalin Marinas , Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 1/4] arm64: Document requirements for fine grained traps at boot In-Reply-To: <20210401180942.35815-2-broonie@kernel.org> References: <20210401180942.35815-1-broonie@kernel.org> <20210401180942.35815-2-broonie@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: broonie@kernel.org, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210408_180019_416888_12D80BA0 X-CRM114-Status: GOOD ( 23.55 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Thu, 01 Apr 2021 19:09:39 +0100, Mark Brown wrote: > > The arm64 FEAT_FGT extension introduces a set of traps to EL2 for accesses > to small sets of registers and instructions from EL1 and EL0, access to > which is controlled by EL3. Require access to it so that it is > available to us in future and so that we can ensure these traps are > disabled during boot. > > Signed-off-by: Mark Brown > --- > Documentation/arm64/booting.rst | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst > index 7552dbc1cc54..92ec0bea1af5 100644 > --- a/Documentation/arm64/booting.rst > +++ b/Documentation/arm64/booting.rst > @@ -270,6 +270,12 @@ Before jumping into the kernel, the following conditions must be met: > having 0b1 set for the corresponding bit for each of the auxiliary > counters present. > > + For CPUs with the Fine Grained Traps (FEAT_FGT) extension present: > + > + - If EL3 is present and the kernel is entered at EL2: > + > + - SCR_EL3.FGTEn (bit 27) must be initialised to 0b1. > + > The requirements described above for CPU mode, caches, MMUs, architected > timers, coherency and system registers apply to all CPUs. All CPUs must > enter the kernel in the same exception level. Acked-by: Marc Zyngier M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel