mbox series

[v3,0/2] Driver for Open Profile for DICE

Message ID 20211213195833.772892-1-dbrazdil@google.com
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Series Driver for Open Profile for DICE | expand

Message

David Brazdil Dec. 13, 2021, 7:58 p.m. UTC 
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 measured hardware/software combination
and can be used by userspace for remote attestation and sealing.

This patchset adds DeviceTree bindings for the DICE device referencing
a reserved memory region containing the CDIs, and a driver that exposes
the memory region to userspace via a misc device.

See https://pigweed.googlesource.com/open-dice for more details.

The patches are based on top of v5.16-rc5 and can also be found here:
  https://android-kvm.googlesource.com/linux topic/dice_v3

Changes since v2:
  * renamed from 'dice' to 'open-dice'
  * replaced ioctls with read/write
  * replaced memzero_explicit with memset
  * allowed multiple instances
  * expanded Kconfig description

Changes since v1:
  * converted to miscdevice
  * all mappings now write-combine to simplify semantics
  * removed atomic state, any attempt at exclusive access
  * simplified wipe, applied on ioctl, not on release
  * fixed ioctl return value

David Brazdil (2):
  dt-bindings: firmware: Add Open Profile for DICE
  misc: open-dice: Add driver to expose DICE data to userspace

 .../bindings/firmware/google,open-dice.yaml   |  51 +++++
 drivers/misc/Kconfig                          |  12 ++
 drivers/misc/Makefile                         |   1 +
 drivers/misc/open-dice.c                      | 197 ++++++++++++++++++
 4 files changed, 261 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/firmware/google,open-dice.yaml
 create mode 100644 drivers/misc/open-dice.c

--
2.34.1.173.g76aa8bc2d0-goog

Comments

David Brazdil Dec. 21, 2021, 5:43 p.m. UTC | #1 
On Thu, Dec 16, 2021 at 09:21:00AM -0600, Rob Herring wrote:
> On Wed, Dec 15, 2021 at 3:08 PM David Brazdil <dbrazdil@google.com> wrote:
> >
> > Hi Rob,
> >
> > > > +        dice_reserved: dice@12340000 {
> > > > +            reg = <0x00 0x12340000 0x2000>;
> > > > +            no-map;
> > > > +        };
> > > > +    };
> > > > +
> > > > +    dice {
> > > > +        compatible = "google,open-dice";
> > > > +        memory-region = <&dice_reserved>;
> > >
> > > There's no need for this indirection. Just add the compatible to the
> > > dice@12340000 node. You can bind drivers to /reserved-memory nodes.
> >
> > I have not found a way to make that work for kernel modules. Built-in
> > drivers can bind with RESERVEDMEM_OF_DECLARE, which puts an entry in
> > __reservedmem_of_table and __reserved_mem_init_node() iterates find it
> > there. A good case study might be CONFIG_TEGRA210_EMC, where the driver
> > itself can be a module but the rmem parsing is always built-in under
> > CONFIG_TEGRA210_EMC_TABLE. I don't think that's worth the trouble with
> > this driver.
> 
> I forgot you have to add the compatible to reserved_mem_matches in
> drivers/of/platform.c.

Oh nice! Exactly what I was looking for, thanks. I'll respin shortly.

David