s390: add options to change branch prediction behaviour for the kernel

[linux-2.6-microblaze.git] / arch / s390 / kernel / alternative.c

diff --git a/arch/s390/kernel/alternative.c b/arch/s390/kernel/alternative.c
index 1abf4f3..2247613 100644 (file)
--- a/arch/s390/kernel/alternative.c
+++ b/arch/s390/kernel/alternative.c
@@ -15,6 +15,29 @@ static int __init disable_alternative_instructions(char *str)
 
 early_param("noaltinstr", disable_alternative_instructions);
 
+static int __init nobp_setup_early(char *str)
+{
+       bool enabled;
+       int rc;
+
+       rc = kstrtobool(str, &enabled);
+       if (rc)
+               return rc;
+       if (enabled && test_facility(82))
+               __set_facility(82, S390_lowcore.alt_stfle_fac_list);
+       else
+               __clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+       return 0;
+}
+early_param("nobp", nobp_setup_early);
+
+static int __init nospec_setup_early(char *str)
+{
+       __clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+       return 0;
+}
+early_param("nospec", nospec_setup_early);
+
 struct brcl_insn {
        u16 opc;
        s32 disp;