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=-3.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 524BBC072B3 for ; Fri, 17 May 2019 16:48:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21D2521726 for ; Fri, 17 May 2019 16:48:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="apNC443I" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727461AbfEQQrw (ORCPT ); Fri, 17 May 2019 12:47:52 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:43841 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727302AbfEQQrv (ORCPT ); Fri, 17 May 2019 12:47:51 -0400 Received: by mail-pf1-f194.google.com with SMTP id c6so3933962pfa.10 for ; Fri, 17 May 2019 09:47:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ZEOBQ+tiRCBCDhxOnqUK3ak9dZiYIaMI5j8XdfHoJPo=; b=apNC443IjOu26zOUT73921FGrnZ1n43OPBcwr8RIvJ+ZwA785Xj8ae/wdc1rrNkXDy 23fQnlF+WLg7ie94sC7Saky9o7IuCQHw5EtDYIwfJ3Hhg5BFCSLEIgSAq/ijzHWjvVtg gNLSxE2QaGgEAbJZHjlXf9OVihYSzy2yxrfjA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ZEOBQ+tiRCBCDhxOnqUK3ak9dZiYIaMI5j8XdfHoJPo=; b=KFw6yiagUxiesEuQLVHzJdl9bxwuKNKsHyDIVDpOkEpUT0GP+sAI4i6FFCGN0pvSxV YoZrW5kJI/zptOsjCKjHZtHdheWLeelfjWFNbycrZ8XZDX0XTGsddtl7fClQKMR1e+pB e4JFf1hOxuVGQaT7dDokIe/b/+WvhyDQoqw3lozVyyvQpOOYV7GRwAU4v3UXHybGKWYd BkQMqBpOhbtlYn4Briww3D/h8j4Fxk7nq9ElkhP19mKgw7+C8V6XidnmK46b6xrZRk7y rLOvFBwIO6707vgidzVNHGODsnGT1zcrUJ3wt+VYqIkZy0L3iE63ARlEo9mA0+R/YBt9 EL5A== X-Gm-Message-State: APjAAAWHEd2Ml+NrhHC9go4w3Tv7mI685hUi4oPDUvAlSYpD0mPNeOCi xjm/Mu5ktkPrHxvw73KBhXG0qA== X-Google-Smtp-Source: APXvYqxzWh7+qSyhy1qYyWLoyY4I2do1NdTj92SZJu+yMhoeS1eAS3iHOrpPbfYELyOXmcFNaUiphA== X-Received: by 2002:a63:170a:: with SMTP id x10mr56459139pgl.355.1558111671057; Fri, 17 May 2019 09:47:51 -0700 (PDT) Received: from smtp.gmail.com ([2620:15c:202:1:fa53:7765:582b:82b9]) by smtp.gmail.com with ESMTPSA id l141sm12229810pfd.24.2019.05.17.09.47.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 17 May 2019 09:47:50 -0700 (PDT) From: Stephen Boyd To: linux-kernel@vger.kernel.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Evan Green , Rob Herring , Bjorn Andersson , Andy Gross , Will Deacon , Catalin Marinas Subject: [RFC/PATCH 0/5] Read-only memremap() proposal Date: Fri, 17 May 2019 09:47:41 -0700 Message-Id: <20190517164746.110786-1-swboyd@chromium.org> X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org This patch series implements a read-only version of memremap() via a new MEMREMAP_RO flag. If this is passed in the mapping call, we'll try to map the memory region as read-only if it doesn't intersect with an existing mapping. Otherwise, we'll try to fallback to other flags to try to map the memory that way. The main use case I have is to map the command-db memory region on Qualcomm devices with a read-only mapping. It's already a const marked pointer and the API returns const pointers as well, so this series makes sure that even stray writes can't modify the memory. To get there we introduce a devm version of memremap() for a reserved memory region, add a memremap() flag, and implement support for that flag on arm64. Cc: Evan Green Cc: Rob Herring Cc: Bjorn Andersson Cc: Andy Gross Cc: Will Deacon Cc: Catalin Marinas Stephen Boyd (5): reserved_mem: Add a devm_memremap_reserved_mem() API soc: qcom: cmd-db: Migrate to devm_memremap_reserved_mem() memremap: Add support for read-only memory mappings arm64: Add support for arch_memremap_ro() soc: qcom: cmd-db: Map with read-only mappings arch/arm64/include/asm/io.h | 1 + drivers/of/of_reserved_mem.c | 45 +++++++++++++++++++++++++++++++++ drivers/soc/qcom/cmd-db.c | 14 +++------- include/linux/io.h | 1 + include/linux/of_reserved_mem.h | 6 +++++ kernel/iomem.c | 15 +++++++++-- 6 files changed, 70 insertions(+), 12 deletions(-) base-commit: 9e98c678c2d6ae3a17cb2de55d17f69dddaa231b prerequisite-patch-id: 62119e27c0c0686e02f0cb55c296b878fb7f5e47 prerequisite-patch-id: bda32cfc1733c245ae3f141d7c27b18e4adcc628 prerequisite-patch-id: b8f8097161bd15e87d54dcfbfa67b9ca1abc7204 -- Sent by a computer through tubes