Re: [PATCH v2] nvmem: core: Set no-read-write provider to avoid userspace read/write
From: Gaurav Kohli
Date: Mon Apr 01 2019 - 00:52:37 EST
Hi Srinivas,
Thanks for the patch, Can you please merge , So will cherry pick the same.
Regards
Gaurav
On 3/25/2019 11:45 AM, Gaurav Kohli wrote:
On 3/22/2019 11:42 PM, Gaurav Kohli wrote:
Hi Srinivas,
Thanks for the patch, Something like this only i have tested in the
morning, instead of unused, i have put dev group inside config as well.
We will test the exact patch and update the same.
Regards
Gaurav
On 3/22/2019 8:32 PM, Srinivas Kandagatla wrote:
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!
Hi Srinivas,
Thanks for the patch.
I have checked the patch and also tested the same , and it is working
as expected(no creation of nvmem sysfs)
Applied with some conflict on line 41.
Reviewed-by: Gaurav Kohli <gkohli@xxxxxxxxxxxxxx>
Tested-by: Gaurav Kohli <gkohli@xxxxxxxxxxxxxx>
Regards
Gaurav
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@xxxxxxxxxx>
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@xxxxxxxxxx>
---
ÂDocumentation/ABI/stable/sysfs-bus-nvmem |Â 2 ++
Âdrivers/nvmem/KconfigÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 5 +++++
Âdrivers/nvmem/core.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | 11 ++++++-----
Â3 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:
ÂÂÂÂÂÂÂÂ This file allows user to read/write the raw NVMEM contents.
ÂÂÂÂÂÂÂÂ Permissions for write to this file depends on the nvmem
ÂÂÂÂÂÂÂÂ provider configuration.
+ÂÂÂÂÂÂÂ Note: This file is not present if CONFIG_NVMEM_NO_SYSFS_ENTRY
+ÂÂÂÂÂÂÂ is enabled
ÂÂÂÂÂÂÂÂ ex:
ÂÂÂÂÂÂÂÂ 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
ÂÂÂÂÂÂ This driver can also be built as a module. If so, the module
ÂÂÂÂÂÂ will be called nvmem-sc27xx-efuse.
+config NVMEM_NO_SYSFS_ENTRY
+ÂÂÂ bool "No nvmem sysfs entry"
+
+ÂÂÂ help
+ÂÂÂÂÂÂÂ Say Yes if you do not want to add nvmem entry to sysfs.
Âendif
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 = {
ÂÂÂÂ .attrsÂÂÂÂÂÂÂ = nvmem_attrs,
Â};
-static const struct attribute_group *nvmem_rw_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_rw_dev_groups[] = {
ÂÂÂÂ &nvmem_bin_rw_group,
ÂÂÂÂ NULL,
Â};
@@ -240,7 +240,7 @@ static const struct attribute_group
nvmem_bin_ro_group = {
ÂÂÂÂ .attrsÂÂÂÂÂÂÂ = nvmem_attrs,
Â};
-static const struct attribute_group *nvmem_ro_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_ro_dev_groups[] = {
ÂÂÂÂ &nvmem_bin_ro_group,
ÂÂÂÂ NULL,
Â};
@@ -265,7 +265,7 @@ static const struct attribute_group
nvmem_bin_rw_root_group = {
ÂÂÂÂ .attrsÂÂÂÂÂÂÂ = nvmem_attrs,
Â};
-static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_rw_root_dev_groups[] = {
ÂÂÂÂ &nvmem_bin_rw_root_group,
ÂÂÂÂ NULL,
Â};
@@ -289,7 +289,7 @@ static const struct attribute_group
nvmem_bin_ro_root_group = {
ÂÂÂÂ .attrsÂÂÂÂÂÂÂ = nvmem_attrs,
Â};
-static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
+static const __maybe_unused struct attribute_group
*nvmem_ro_root_dev_groups[] = {
ÂÂÂÂ &nvmem_bin_ro_root_group,
ÂÂÂÂ NULL,
Â};
@@ -688,6 +688,7 @@ struct nvmem_device *nvmem_register(const struct
nvmem_config *config)
ÂÂÂÂ nvmem->read_only = device_property_present(config->dev,
"read-only") |
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ config->read_only;
+#if !defined(CONFIG_NVMEM_NO_SYSFS_ENTRY)
ÂÂÂÂ if (config->root_only)
ÂÂÂÂÂÂÂÂ nvmem->dev.groups = nvmem->read_only ?
ÂÂÂÂÂÂÂÂÂÂÂÂ nvmem_ro_root_dev_groups :
@@ -696,7 +697,7 @@ struct nvmem_device *nvmem_register(const struct
nvmem_config *config)
ÂÂÂÂÂÂÂÂ nvmem->dev.groups = nvmem->read_only ?
ÂÂÂÂÂÂÂÂÂÂÂÂ nvmem_ro_dev_groups :
ÂÂÂÂÂÂÂÂÂÂÂÂ nvmem_rw_dev_groups;
-
+#endif
ÂÂÂÂ device_initialize(&nvmem->dev);
ÂÂÂÂ dev_dbg(&nvmem->dev, "Registering nvmem device %s\n",
config->name);
--
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