Russell Currey d2a3c13198 powerpc/powernv: Get STF barrier requirements from device-tree ...

The device-tree property no-need-store-drain-on-priv-state-switch is
equivalent to H_CPU_BEHAV_NO_STF_BARRIER from the
H_CPU_GET_CHARACTERISTICS hcall on pseries.

Since commit 84ed26fd00 ("powerpc/security: Add a security feature for
STF barrier") powernv systems with this device-tree property have been
enabling the STF barrier when they have no need for it.  This patch
fixes this by clearing the STF barrier feature on those systems.

Fixes: 84ed26fd00 ("powerpc/security: Add a security feature for STF barrier")
Reported-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220404101536.104794-2-ruscur@russell.cc

2022-05-22 15:58:28 +10:00

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