linux-kernel - Re: [PATCH v2] nvmem: core: Set no-read-write provider to avoid userspace read/write

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Date:   Wed, 20 Mar 2019 14:34:25 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Gaurav Kohli <gkohli@...eaurora.org>, linux-kernel@...r.kernel.org
Cc:     linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v2] nvmem: core: Set no-read-write provider to avoid
 userspace read/write

On 17/03/2019 14:12, Gaurav Kohli wrote:
> Current nvmem framework allows user space to read all register space
> populated by nvmem binary file, In case we don't want to expose value
> of registers to userspace and only want kernel space to read cell
> value from nvmem_cell_read_u32.
> 
> To protect the same, Add no-read-write property to prevent read
> from userspace.
> 

Can you explain the real need of this?
Is there any issue you are noticing while reading nvmem content from 
userspace?

I don't think this is the right way to do this, its misleading in many 
ways. Also this should not be a part of DT binding.

If we decide that we need this feature, then better way to do this using 
a new Kernel config.

thanks,
srini