linux-kernel - [PATCH 0/6] Enable CAAM on i.MX7s fix TrustZone issues

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Message-Id: <1516804499-12663-1-git-send-email-pure.logic@nexus-software.ie>
Date:   Wed, 24 Jan 2018 14:34:53 +0000
From:   Bryan O'Donoghue <pure.logic@...us-software.ie>
To:     horia.geanta@....com, aymen.sghaier@....com,
        linux-crypto@...r.kernel.org
Cc:     fabio.estevam@....com, peng.fan@....com,
        herbert@...dor.apana.org.au, davem@...emloft.net,
        lukas.auer@...ec.fraunhofer.de, rui.silva@...aro.org,
        ryan.harkin@...aro.org, linux-kernel@...r.kernel.org,
        Bryan O'Donoghue <pure.logic@...us-software.ie>
Subject: [PATCH 0/6] Enable CAAM on i.MX7s fix TrustZone issues

This patch-set enables CAAM on the i.MX7s and fixes a number of issues
identified with the CAAM driver and hardware when TrustZone mode is
enabled.

The first block of patches are simple bug-fixes, followed by a second block
of patches which are simple enabling patches for the i.MX7Solo - note we
aren't enabling for the i.MX7Dual since we don't have hardware to test that
out but it should be a 1:1 mapping for others to enable when appropriate.

The final block in this series implements a fix for using the CAAM when
OPTEE/TrustZone is enabled. The various details are logged in these
threads.

Link: https://github.com/OP-TEE/optee_os/issues/1408
Link: https://tinyurl.com/yam5gv9a
Link: https://patchwork.ozlabs.org/cover/865042

In simple terms, when TrustZone is active the first page of the CAAM
becomes inaccessible to Linux as it has a special 'TZ bit' associated with
it that software cannot toggle or even view AFAIK.

The patches here then

1. Detect when TrustZone is active
2. Detect if u-boot (or OPTEE) has already initialized the RNG

and loads the CAAM driver in a different way - skipping over the RNG
initialization that Linux now no-longer has permissions to carry out.

Should #1 be true but #2 not be true, driver loading stops (and Rui's patch
for the NULL pointer dereference fixes a cash on this path). If #2 is true
but #1 is not then it's a NOP as Linux has full permission to rewrite the
deco registers in the first page of CAAM registers.

Finally then if #1 and #2 are true, the fixes here allow the CAAM to come
up and for the RNG to be useable again.

Bryan O'Donoghue (3):
  crypto: caam: Fix endless loop when RNG is already initialized
  crypto: caam: add logic to detect when running under TrustZone
  crypto: caam: detect RNG init when TrustZone is active

Rui Miguel Silva (3):
  crypto: caam: Fix null dereference at error path
  ARM: dts: imx7s: add CAAM device node
  imx7d: add CAAM clocks

 arch/arm/boot/dts/imx7s.dtsi            | 26 +++++++++++++++++++
 drivers/clk/imx/clk-imx7d.c             |  3 +++
 drivers/crypto/caam/ctrl.c              | 45 ++++++++++++++++++++++++++++++---
 drivers/crypto/caam/intern.h            |  1 +
 include/dt-bindings/clock/imx7d-clock.h |  5 +++-
 5 files changed, 76 insertions(+), 4 deletions(-)

-- 
2.7.4