From 68cb884e12288cdbc044895affd528ceb98a815b Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Fri, 27 Apr 2018 07:36:40 +0200 Subject: s390: report spectre mitigation via syslog [ 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 Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/nospec-branch.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/s390') diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c index daa36a38a8b7..7387ebace891 100644 --- a/arch/s390/kernel/nospec-branch.c +++ b/arch/s390/kernel/nospec-branch.c @@ -33,6 +33,16 @@ static int __init nospec_setup_early(char *str) } 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); -- cgit v1.2.3