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: Mon, 25 Mar 2019 11:45:13 +0530 Message-ID: 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> <4451d4f2-d651-9db6-99af-e07870fc699a@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <4451d4f2-d651-9db6-99af-e07870fc699a@codeaurora.org> 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 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 Tested-by: Gaurav Kohli 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 >> 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.