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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BB1EC77B7E for ; Thu, 1 Jun 2023 12:26:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232009AbjFAM00 (ORCPT ); Thu, 1 Jun 2023 08:26:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231759AbjFAM0Z (ORCPT ); Thu, 1 Jun 2023 08:26:25 -0400 Received: from mo4-p01-ob.smtp.rzone.de (mo4-p01-ob.smtp.rzone.de [85.215.255.50]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BD329D; Thu, 1 Jun 2023 05:26:22 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1685622380; cv=none; d=strato.com; s=strato-dkim-0002; b=XiG+Vi6gGHQowjb9Bf55mFt3xWEo+WLrPcjZ59s+YmLHF78da17+FBfIctd0IADxwe 2d5QFc+abGWb6yCVUXWkelWacXu3jdoY38irxUjSsdU2wJsmlKb7AHkz2JolSG+Ov/K1 1f+teExknD4NzUh5Q3BdknlwxDBv1/qfFbeKNumeNKoICrhIlgZFra6zLXocBIo7KoZk VX0Yzydi3Qhus7njRfgDKcSFpRQSjGhZm+6rNJj+kldbXdF8deQDajRHPrp9E9R3eRWR 3FLB/nPVajRVn/BQ5WqrIieRSF7BKYAloP3/O7FhyhzEeHe1edkKJ8ToOAScvsDqCMZS ReFg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1685622380; s=strato-dkim-0002; d=strato.com; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=4nlI0t8cVc1lkSa6LiiU7VWHaD2KWNpreTHmhmut4hU=; b=V6RfA2WGKv2qpcqLiAuBj4s/LF5jRgIvir2h1kaHmi/32a3PACXmprmYDwo5GbAqgC xNEYj2j9mADfbA1LTolLvyRqWSPdvRLZfTc6VihRiZfGK/r4VZ4fG839oJ0fGm8uUDLY 3QYH6tyVcBP5gQ0i5vmS3YW7hlYrB9qYlNsPBotUrLxiwhSJldnK5FvcQR5ODlkJOrKa Iv2QQfe+FHTC873CwYhf050DVBWzNm5XtASa10LcJGKo+E5eQewj95d22B9SfTgkke/g hk6XJi2JWxhSfrmKGdeeer8o3J1HXbmYfpC/LWrIqq8q9PKw7Vwc/SM2iyi0PjQwTmGo U5HA== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo01 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1685622380; s=strato-dkim-0002; d=gerhold.net; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=4nlI0t8cVc1lkSa6LiiU7VWHaD2KWNpreTHmhmut4hU=; b=iYLH01kMgs6ZDj7J8rFGkkbm/WKj3keNH6pA8doB01oiknePtmcbw0ewNa2eJOk3UM 7WWrT8HLfgsIeIw8F+VxPPta5PmQa+NgvW1HcVGb/B7kuIreqATN6BZ/X6dkCquYgB1Z RAlCbp6kzzPR1DUVkTG1JkX0JzCh9coJpD0GTnkpUFvRwnt2O8H37+cJYQxBKcCE/FVz epAbZHQJYHqscbDQPRcZ1E/VHfEFUvI5Dhes9xudYFDW7ctLZcsiraUlDITwxMTxj7Ic COPmoZV13XaRCaI5xx0JaGxntDBXJkIAP1gLyojgU06HVrk5pjVbJjX2cC9ACe6HvpF+ C2Ww== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1685622380; s=strato-dkim-0003; d=gerhold.net; h=In-Reply-To:References:Message-ID:Subject:Cc:To:From:Date:Cc:Date: From:Subject:Sender; bh=4nlI0t8cVc1lkSa6LiiU7VWHaD2KWNpreTHmhmut4hU=; b=MNsSLRO1kKKD7zWnKTz1vLypyEmOef19RLKMhrf9ruh2rOoYJfjZ1zHZEGt9OmWr6p 0DafpbOwkx4aZdSzsfAg== X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVOQ/OcYgojyw4j34+u261EJF5OxJD4peA9J/h" Received: from gerhold.net by smtp.strato.de (RZmta 49.4.0 DYNA|AUTH) with ESMTPSA id j6420az51CQJquT (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Thu, 1 Jun 2023 14:26:19 +0200 (CEST) Date: Thu, 1 Jun 2023 14:26:12 +0200 From: Stephan Gerhold To: Bjorn Andersson Cc: Bjorn Andersson , Konrad Dybcio , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/3] soc: qcom: rmtfs: Support discarding guard pages Message-ID: References: <20230530233643.4044823-1-quic_bjorande@quicinc.com> <20230530233643.4044823-3-quic_bjorande@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230530233643.4044823-3-quic_bjorande@quicinc.com> Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, May 30, 2023 at 04:36:42PM -0700, Bjorn Andersson wrote: > In some configurations, the exact placement of the rmtfs shared memory > region isn't so strict. The DeviceTree author can then choose to use the > "size" property and rely on the OS for placement (in combination with > "alloc-ranges", if desired). > > But on some platforms the rmtfs memory region may not be allocated > adjacent to regions allocated by other clients. Add support for > discarding the first and last 4k block in the region, if > qcom,use-guard-pages is specified in DeviceTree. > > Signed-off-by: Bjorn Andersson > --- > > Changes since v1: > - Drop the dma_alloc_coherent() based approach and just add support for > the guard pages. > > drivers/soc/qcom/rmtfs_mem.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c > index f83811f51175..28238974d913 100644 > --- a/drivers/soc/qcom/rmtfs_mem.c > +++ b/drivers/soc/qcom/rmtfs_mem.c > @@ -213,6 +213,16 @@ static int qcom_rmtfs_mem_probe(struct platform_device *pdev) > goto put_device; > } > > + /* > + * If requested, discard the first and last 4k block in order to ensure > + * that the rmtfs region isn't adjacent to other protected regions. > + */ > + if (of_property_present(node, "qcom,use-guard-pages")) { > + rmtfs_mem->addr += SZ_4K; > + rmtfs_mem->base += SZ_4K; > + rmtfs_mem->size -= 2 * SZ_4K; > + } It probably doesn't make a big difference in practice but I would say there is no need to even memremap() the guard pages. If you adjust the ->addr and ->size before the memremap() then you don't need to modify the ->base at all. Thanks, Stephan