From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gaurav Kohli Subject: Re: [PATCH v2] nvmem: core: Set no-read-write provider to avoid userspace read/write Date: Fri, 22 Mar 2019 23:42:43 +0530 Message-ID: <4451d4f2-d651-9db6-99af-e07870fc699a@codeaurora.org> References: <1552831940-7327-1-git-send-email-gkohli@codeaurora.org> <48a71861-c60b-7fe7-d4af-5269cd7c20eb@linaro.org> <5f11070f-bf9b-c313-9a78-e412a2fb2908@codeaurora.org> <865519b5-62c9-3eb3-3855-eebf98bded85@linaro.org> <68755fdb-b2c6-ac25-a786-7593a692a173@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Srinivas Kandagatla , linux-kernel@vger.kernel.org Cc: linux-arm-msm@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org 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! > >>> >>> 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 > 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 > --- >  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); -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.