lkml.org 
[lkml]   [2022]   [Jun]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.18 640/879] powerpc/powernv: Get STF barrier requirements from device-tree
    Date
    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


    \
     
     \ /
      Last update: 2022-06-08 03:36    [W:4.023 / U:0.284 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site