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    Subject[PATCH 4.14 57/80] s390: report spectre mitigation via syslog
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Martin Schwidefsky <schwidefsky@de.ibm.com>


    [ Upstream commit bc035599718412cfba9249aa713f90ef13f13ee9 ]

    Add a boot message if either of the spectre defenses is active.
    The message is
    "Spectre V2 mitigation: execute trampolines."
    or "Spectre V2 mitigation: limited branch prediction."

    Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    arch/s390/kernel/nospec-branch.c | 10 ++++++++++
    1 file changed, 10 insertions(+)

    --- a/arch/s390/kernel/nospec-branch.c
    +++ b/arch/s390/kernel/nospec-branch.c
    @@ -33,6 +33,16 @@ static int __init nospec_setup_early(cha
    }
    early_param("nospec", nospec_setup_early);

    +static int __init nospec_report(void)
    +{
    + if (IS_ENABLED(CC_USING_EXPOLINE) && !nospec_disable)
    + pr_info("Spectre V2 mitigation: execute trampolines.\n");
    + if (__test_facility(82, S390_lowcore.alt_stfle_fac_list))
    + pr_info("Spectre V2 mitigation: limited branch prediction.\n");
    + return 0;
    +}
    +arch_initcall(nospec_report);
    +
    #ifdef CONFIG_EXPOLINE

    int nospec_disable = IS_ENABLED(CONFIG_EXPOLINE_OFF);

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