Date:   Wed, 22 Dec 2021 15:33:43 -0400
From:   Rob Herring <robh@kernel.org>
To:     David Brazdil <dbrazdil@google.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Frank Rowand <frowand.list@gmail.com>,
        Will Deacon <will@kernel.org>,
        Andrew Scull <ascull@google.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 2/2] misc: open-dice: Add driver to expose DICE data
 to userspace
Message-ID: <YcN9lzDMPjkvRDAZ@robh.at.kernel.org>
References: <20211221174502.63891-1-dbrazdil@google.com>
 <20211221174502.63891-3-dbrazdil@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20211221174502.63891-3-dbrazdil@google.com>
Precedence: bulk

On Tue, Dec 21, 2021 at 05:45:02PM +0000, David Brazdil wrote:
> Open Profile for DICE is an open protocol for measured boot compatible
> with the Trusted Computing Group's Device Identifier Composition
> Engine (DICE) specification. The generated Compound Device Identifier
> (CDI) certificates represent the hardware/software combination measured
> by DICE, and can be used for remote attestation and sealing.
> 
> Add a driver that exposes reserved memory regions populated by firmware
> with DICE CDIs and exposes them to userspace via a character device.
> 
> Userspace obtains the memory region's size from read() and calls mmap()
> to create a mapping of the memory region in its address space. The
> mapping is not allowed to be write+shared, giving userspace a guarantee
> that the data were not overwritten by another process.
> 
> Userspace can also call write(), which triggers a wipe of the DICE data
> by the driver. Because both the kernel and userspace mappings use
> write-combine semantics, all clients observe the memory as zeroed after
> the syscall has returned.
> 
> Cc: Andrew Scull <ascull@google.com>
> Cc: Will Deacon <will@kernel.org>
> Signed-off-by: David Brazdil <dbrazdil@google.com>
> ---
>  drivers/misc/Kconfig     |  12 +++
>  drivers/misc/Makefile    |   1 +
>  drivers/misc/open-dice.c | 188 +++++++++++++++++++++++++++++++++++++++
>  drivers/of/platform.c    |   1 +

Acked-by: Rob Herring <robh@kernel.org>

>  4 files changed, 202 insertions(+)
>  create mode 100644 drivers/misc/open-dice.c