s390: move nobp parameter functions to nospec-branch.c

BugLink: http://bugs.launchpad.net/bugs/1768474

[ Upstream commit b2e2f43a ]

Keep the code for the nobp parameter handling with the code for
expolines. Both are related to the spectre v2 mitigation.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/s390/kernel/Makefile

@@ -45,11 +45,11 @@ obj-y	+= debug.o irq.o ipl.o dis.o diag.o sclp.o vdso.o
 obj-y	+= sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o
 obj-y	+= runtime_instr.o cache.o dumpstack.o
 obj-y	+= entry.o reipl.o relocate_kernel.o alternative.o
+obj-y	+= nospec-branch.o
 
 extra-y				+= head.o head64.o vmlinux.lds
 
-obj-$(CONFIG_EXPOLINE)		+= nospec-branch.o
-CFLAGS_REMOVE_expoline.o	+= $(CC_FLAGS_EXPOLINE)
+CFLAGS_REMOVE_nospec-branch.o	+= $(CC_FLAGS_EXPOLINE)
 
 obj-$(CONFIG_MODULES)		+= s390_ksyms.o module.o
 obj-$(CONFIG_SMP)		+= smp.o

arch/s390/kernel/alternative.c

@@ -14,29 +14,6 @@ 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;

arch/s390/kernel/nospec-branch.c

@@ -3,6 +3,31 @@
 #include <asm/facility.h>
 #include <asm/nospec-branch.h>
 
+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);
+
+#ifdef CONFIG_EXPOLINE
+
 int nospec_call_disable = IS_ENABLED(CONFIG_EXPOLINE_OFF);
 int nospec_return_disable = !IS_ENABLED(CONFIG_EXPOLINE_FULL);
 
@@ -99,3 +124,5 @@ void __init nospec_init_branches(void)
 	nospec_call_revert(__nospec_call_start, __nospec_call_end);
 	nospec_return_revert(__nospec_return_start, __nospec_return_end);
 }
+
+#endif /* CONFIG_EXPOLINE */