From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: [PATCH v3 5/5] soc: qcom: cmd-db: Map with read-only mappings Date: Tue, 10 Sep 2019 09:09:03 -0700 Message-ID: <20190910160903.65694-6-swboyd@chromium.org> References: <20190910160903.65694-1-swboyd@chromium.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190910160903.65694-1-swboyd@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: Dan Williams Cc: linux-kernel@vger.kernel.org, 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 List-Id: devicetree@vger.kernel.org The command DB is read-only already to the kernel because everything is const marked once we map it. Let's go one step further and try to map the memory as read-only in the page tables. This should make it harder for random code to corrupt the database and change the contents. Cc: Evan Green Cc: Rob Herring Cc: Bjorn Andersson Cc: Andy Gross Cc: Will Deacon Cc: Catalin Marinas Cc: Dan Williams Reviewed-by: Bjorn Andersson Signed-off-by: Stephen Boyd --- drivers/soc/qcom/cmd-db.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c index 10a34d26b753..6365e8260282 100644 --- a/drivers/soc/qcom/cmd-db.c +++ b/drivers/soc/qcom/cmd-db.c @@ -240,7 +240,8 @@ static int cmd_db_dev_probe(struct platform_device *pdev) { int ret = 0; - cmd_db_header = devm_memremap_reserved_mem(&pdev->dev, MEMREMAP_WB); + cmd_db_header = devm_memremap_reserved_mem(&pdev->dev, + MEMREMAP_RO | MEMREMAP_WB); if (IS_ERR(cmd_db_header)) { ret = PTR_ERR(cmd_db_header); cmd_db_header = NULL; -- Sent by a computer through tubes