s390: enforce CONFIG_SMP

There never have been distributions that shiped with CONFIG_SMP=n for
s390. In addition the kernel currently doesn't even compile with
CONFIG_SMP=n for s390. Most likely it wouldn't even work, even if we
fix the compile error, since nobody tests it, since there is no use
case that I can think of.
Therefore simply enforce CONFIG_SMP and get rid of some more or
less unused code.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

5 files changed, 1 insertions, 11 deletions

diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index b0478d01a0c5..0f255b54b051 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -53,6 +53,7 @@ obj-y	+= sysinfo.o lgr.o os_info.o machine_kexec.o pgm_check.o
 obj-y	+= runtime_instr.o cache.o fpu.o dumpstack.o guarded_storage.o sthyi.o
 obj-y	+= entry.o reipl.o relocate_kernel.o kdebugfs.o alternative.o
 obj-y	+= nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o unwind_bc.o
+obj-y	+= smp.o
 
 extra-y				+= head64.o vmlinux.lds
 
@@ -60,7 +61,6 @@ obj-$(CONFIG_SYSFS)		+= nospec-sysfs.o
 CFLAGS_REMOVE_nospec-branch.o	+= $(CC_FLAGS_EXPOLINE)
 
 obj-$(CONFIG_MODULES)		+= module.o
-obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_SCHED_TOPOLOGY)	+= topology.o
 obj-$(CONFIG_HIBERNATION)	+= suspend.o swsusp.o
 obj-$(CONFIG_AUDIT)		+= audit.o
diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
index 9e87b68be21c..ac06c3949ab3 100644
--- a/arch/s390/kernel/dumpstack.c
+++ b/arch/s390/kernel/dumpstack.c
@@ -199,9 +199,7 @@ void die(struct pt_regs *regs, const char *str)
 #ifdef CONFIG_PREEMPT
 	pr_cont("PREEMPT ");
 #endif
-#ifdef CONFIG_SMP
 	pr_cont("SMP ");
-#endif
 	if (debug_pagealloc_enabled())
 		pr_cont("DEBUG_PAGEALLOC");
 	pr_cont("\n");
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 3f4d272577d3..270d1d145761 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -986,14 +986,12 @@ ENTRY(psw_idle)
 	stg	%r3,__SF_EMPTY(%r15)
 	larl	%r1,.Lpsw_idle_lpsw+4
 	stg	%r1,__SF_EMPTY+8(%r15)
-#ifdef CONFIG_SMP
 	larl	%r1,smp_cpu_mtid
 	llgf	%r1,0(%r1)
 	ltgr	%r1,%r1
 	jz	.Lpsw_idle_stcctm
 	.insn	rsy,0xeb0000000017,%r1,5,__SF_EMPTY+16(%r15)
 .Lpsw_idle_stcctm:
-#endif
 	oi	__LC_CPU_FLAGS+7,_CIF_ENABLED_WAIT
 	BPON
 	STCK	__CLOCK_IDLE_ENTER(%r2)
@@ -1468,7 +1466,6 @@ ENDPROC(cleanup_critical)
 	mvc	__CLOCK_IDLE_ENTER(8,%r2),__CLOCK_IDLE_EXIT(%r2)
 	mvc	__TIMER_IDLE_ENTER(8,%r2),__TIMER_IDLE_EXIT(%r2)
 1:	# calculate idle cycles
-#ifdef CONFIG_SMP
 	clg	%r9,BASED(.Lcleanup_idle_insn)
 	jl	3f
 	larl	%r1,smp_cpu_mtid
@@ -1486,7 +1483,6 @@ ENDPROC(cleanup_critical)
 	la	%r3,8(%r3)
 	la	%r4,8(%r4)
 	brct	%r1,2b
-#endif
 3:	# account system time going idle
 	lg	%r9,__LC_STEAL_TIMER
 	alg	%r9,__CLOCK_IDLE_ENTER(%r2)
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index f8544d517430..2b94b0ad3588 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -461,11 +461,9 @@ static void __init setup_lowcore_dat_off(void)
 	mem_assign_absolute(S390_lowcore.restart_source, lc->restart_source);
 	mem_assign_absolute(S390_lowcore.restart_psw, lc->restart_psw);
 
-#ifdef CONFIG_SMP
 	lc->spinlock_lockval = arch_spin_lockval(0);
 	lc->spinlock_index = 0;
 	arch_spin_lock_setup(0);
-#endif
 	lc->br_r1_trampoline = 0x07f1;	/* br %r1 */
 
 	set_prefix((u32)(unsigned long) lc);
diff --git a/arch/s390/kernel/swsusp.S b/arch/s390/kernel/swsusp.S
index 19a3c427801a..a7baf0b5f818 100644
--- a/arch/s390/kernel/swsusp.S
+++ b/arch/s390/kernel/swsusp.S
@@ -162,7 +162,6 @@ ENTRY(swsusp_arch_resume)
 	larl	%r1,__swsusp_reset_dma
 	lg	%r1,0(%r1)
 	BASR_EX	%r14,%r1
-#ifdef CONFIG_SMP
 	larl	%r1,smp_cpu_mt_shift
 	icm	%r1,15,0(%r1)
 	jz	smt_done
@@ -172,7 +171,6 @@ smt_loop:
 	brc	8,smt_done			/* accepted */
 	brc	2,smt_loop			/* busy, try again */
 smt_done:
-#endif
 	larl	%r1,.Lnew_pgm_check_psw
 	lpswe	0(%r1)
 pgm_check_entry: