Messages in this thread Patch in this message | | | Subject | Re: [PATCH v2] nvmem: core: Set no-read-write provider to avoid userspace read/write | From | Srinivas Kandagatla <> | Date | Fri, 22 Mar 2019 15:02:11 +0000 |
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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.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<-----------------------------------
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