From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
To: Gaurav Kohli <gkohli@codeaurora.org>, linux-kernel@vger.kernel.org
Cc: linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v2] nvmem: core: Set no-read-write provider to avoid userspace read/write
Date: Fri, 22 Mar 2019 15:02:11 +0000 [thread overview]
Message-ID: <cfa22512-2abe-f0db-0576-e6d0cd1eee9c@linaro.org> (raw)
In-Reply-To: <68755fdb-b2c6-ac25-a786-7593a692a173@codeaurora.org>
On 20/03/2019 17:50, Gaurav Kohli wrote:
>
>> Is root only option not helping you in this case?
> Yes we want to protect at root level as well, i mean it is better if we
> can avoid exposing to userspace at all.
Can you try below patch!
>>
>> We could go down the route of adding new config option something like
>> CONFIG_NVMEM_NO_SYSFS_ENTRY to prevent adding nvmem entry in userspace.
>>
>> Let me know if you are happy to create a patch for this change?
>
> I am happy with either way config option or dt binding(seems easy),
> please let me know we will post new patch for the same.
DT way is totally NAK.
--------------------------->cut<-----------------------------------
From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Date: Wed, 20 Mar 2019 16:15:21 +0000
Subject: [PATCH] nvmem: core: add support to NVMEM_NO_SYSFS_ENTRY
Some users might not want to expose nvmem entry to sysfs and
only intend to use kernel interface so add such provision.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
Documentation/ABI/stable/sysfs-bus-nvmem | 2 ++
drivers/nvmem/Kconfig | 5 +++++
drivers/nvmem/core.c | 11 ++++++-----
3 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/Documentation/ABI/stable/sysfs-bus-nvmem
b/Documentation/ABI/stable/sysfs-bus-nvmem
index 5923ab4620c5..12aab0a85fea 100644
--- a/Documentation/ABI/stable/sysfs-bus-nvmem
+++ b/Documentation/ABI/stable/sysfs-bus-nvmem
@@ -6,6 +6,8 @@ Description:
This file allows user to read/write the raw NVMEM contents.
Permissions for write to this file depends on the nvmem
provider configuration.
+ Note: This file is not present if CONFIG_NVMEM_NO_SYSFS_ENTRY
+ is enabled
ex:
hexdump /sys/bus/nvmem/devices/qfprom0/nvmem
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 0a7a470ee859..6ab3276d287c 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -192,4 +192,9 @@ config SC27XX_EFUSE
This driver can also be built as a module. If so, the module
will be called nvmem-sc27xx-efuse.
+config NVMEM_NO_SYSFS_ENTRY
+ bool "No nvmem sysfs entry"
+
+ help
+ Say Yes if you do not want to add nvmem entry to sysfs.
endif
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index b9a0270883a0..c70f183fe379 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -216,7 +216,7 @@ static const struct attribute_group
nvmem_bin_rw_group = {
.attrs = nvmem_attrs,
};
-static const struct attribute_group *nvmem_rw_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_rw_dev_groups[] = {
&nvmem_bin_rw_group,
NULL,
};
@@ -240,7 +240,7 @@ static const struct attribute_group
nvmem_bin_ro_group = {
.attrs = nvmem_attrs,
};
-static const struct attribute_group *nvmem_ro_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_ro_dev_groups[] = {
&nvmem_bin_ro_group,
NULL,
};
@@ -265,7 +265,7 @@ static const struct attribute_group
nvmem_bin_rw_root_group = {
.attrs = nvmem_attrs,
};
-static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_rw_root_dev_groups[] = {
&nvmem_bin_rw_root_group,
NULL,
};
@@ -289,7 +289,7 @@ static const struct attribute_group
nvmem_bin_ro_root_group = {
.attrs = nvmem_attrs,
};
-static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_ro_root_dev_groups[] = {
&nvmem_bin_ro_root_group,
NULL,
};
@@ -688,6 +688,7 @@ struct nvmem_device *nvmem_register(const struct
nvmem_config *config)
nvmem->read_only = device_property_present(config->dev, "read-only") |
config->read_only;
+#if !defined(CONFIG_NVMEM_NO_SYSFS_ENTRY)
if (config->root_only)
nvmem->dev.groups = nvmem->read_only ?
nvmem_ro_root_dev_groups :
@@ -696,7 +697,7 @@ struct nvmem_device *nvmem_register(const struct
nvmem_config *config)
nvmem->dev.groups = nvmem->read_only ?
nvmem_ro_dev_groups :
nvmem_rw_dev_groups;
-
+#endif
device_initialize(&nvmem->dev);
dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
--
2.21.0
--------------------------->cut<-----------------------------------
next prev parent reply other threads:[~2019-03-22 15:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-17 14:12 [PATCH v2] nvmem: core: Set no-read-write provider to avoid userspace read/write Gaurav Kohli
2019-03-20 14:34 ` Srinivas Kandagatla
2019-03-20 15:50 ` Gaurav Kohli
2019-03-20 16:26 ` Srinivas Kandagatla
2019-03-20 17:50 ` Gaurav Kohli
2019-03-21 13:14 ` Marc Gonzalez
2019-03-22 15:02 ` Srinivas Kandagatla [this message]
2019-03-22 18:12 ` Gaurav Kohli
2019-03-25 6:15 ` Gaurav Kohli
2019-04-01 4:52 ` Gaurav Kohli
2019-04-02 7:35 ` Niklas Cassel
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