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| author | Russell Currey <ruscur@russell.cc> | 2022-04-04 20:15:36 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-05-22 15:58:28 +1000 |
| commit | d2a3c131981d4498571908df95c3c9393a00adf5 (patch) | |
| tree | 4a3cc722ffafadf9879e3b3f67de6b846a8029d1 /arch/powerpc/platforms | |
| parent | 2efee6adb56159288bce9d1ab51fc9056d7007d4 (diff) | |
| download | lwn-d2a3c131981d4498571908df95c3c9393a00adf5.tar.gz lwn-d2a3c131981d4498571908df95c3c9393a00adf5.zip | |
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 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
Diffstat (limited to 'arch/powerpc/platforms')
| -rw-r--r-- | arch/powerpc/platforms/powernv/setup.c | 3 |
1 files changed, 3 insertions, 0 deletions
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) |