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From: Stephen Boyd <swboyd@chromium.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	Evan Green <evgreen@chromium.org>,
	Rob Herring <robh+dt@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Andy Gross <agross@kernel.org>, Will Deacon <will.deacon@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>
Subject: [PATCH v2 5/5] soc: qcom: cmd-db: Map with read-only mappings
Date: Fri, 14 Jun 2019 13:37:17 -0700	[thread overview]
Message-ID: <20190614203717.75479-6-swboyd@chromium.org> (raw)
In-Reply-To: <20190614203717.75479-1-swboyd@chromium.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 <evgreen@chromium.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Andy Gross <agross@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 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


WARNING: multiple messages have this Message-ID (diff)
From: Stephen Boyd <swboyd@chromium.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	Will Deacon <will.deacon@arm.com>,
	linux-kernel@vger.kernel.org, Evan Green <evgreen@chromium.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Rob Herring <robh+dt@kernel.org>, Andy Gross <agross@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 5/5] soc: qcom: cmd-db: Map with read-only mappings
Date: Fri, 14 Jun 2019 13:37:17 -0700	[thread overview]
Message-ID: <20190614203717.75479-6-swboyd@chromium.org> (raw)
In-Reply-To: <20190614203717.75479-1-swboyd@chromium.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 <evgreen@chromium.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Andy Gross <agross@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 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


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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2019-06-14 20:37 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-14 20:37 [PATCH v2 0/5] Read-only memremap() Stephen Boyd
2019-06-14 20:37 ` Stephen Boyd
2019-06-14 20:37 ` [PATCH v2 1/5] reserved_mem: Add a devm_memremap_reserved_mem() API Stephen Boyd
2019-06-14 20:37   ` Stephen Boyd
2019-06-14 20:37 ` [PATCH v2 2/5] soc: qcom: cmd-db: Migrate to devm_memremap_reserved_mem() Stephen Boyd
2019-06-14 20:37   ` Stephen Boyd
2019-06-14 20:37 ` [PATCH v2 3/5] memremap: Add support for read-only memory mappings Stephen Boyd
2019-06-14 20:37   ` Stephen Boyd
2019-07-10 14:14   ` Will Deacon
2019-07-10 14:14     ` Will Deacon
2019-07-18 18:00     ` Stephen Boyd
2019-07-18 18:00       ` Stephen Boyd
2019-06-14 20:37 ` [PATCH v2 4/5] arm64: Add support for arch_memremap_ro() Stephen Boyd
2019-06-14 20:37   ` Stephen Boyd
2019-06-14 20:37 ` Stephen Boyd [this message]
2019-06-14 20:37   ` [PATCH v2 5/5] soc: qcom: cmd-db: Map with read-only mappings Stephen Boyd

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