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.
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From: Srinivas Kandagatla <srinivas.kandaga...@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.kandaga...@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
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