Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.18 640/879] powerpc/powernv: Get STF barrier requirements from device-tree | Date | Tue, 7 Jun 2022 19:02:38 +0200 |
| |
From: Russell Currey <ruscur@russell.cc>
[ Upstream commit d2a3c131981d4498571908df95c3c9393a00adf5 ]
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 84ed26fd00c5 ("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: 84ed26fd00c5 ("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 Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/powerpc/platforms/powernv/setup.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c index 378f7e5f18d2..824c3ad7a0fa 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -102,6 +102,9 @@ static void __init init_fw_feat_flags(struct device_node *np) if (fw_feature_is("enabled", "no-need-l1d-flush-kernel-on-user-access", np)) security_ftr_clear(SEC_FTR_L1D_FLUSH_UACCESS); + + if (fw_feature_is("enabled", "no-need-store-drain-on-priv-state-switch", np)) + security_ftr_clear(SEC_FTR_STF_BARRIER); } static void __init pnv_setup_security_mitigations(void) -- 2.35.1
| |