s390/time: always use stckf instead of stck if available

The store clock fast instruction saves a couple of instructions compared
to the store clock instruction. Always use stckf instead of stck if it
is available.

Signed-off-by: Heiko Carstens <[e-mail]>
Reviewed-by: Martin Schwidefsky <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/setup.h

···
 #define MACHINE_FLAG_LPAR	(1UL << 12)
 #define MACHINE_FLAG_SPP	(1UL << 13)
 #define MACHINE_FLAG_TOPOLOGY	(1UL << 14)
-#define MACHINE_FLAG_STCKF	(1UL << 15)
 
 #define MACHINE_IS_VM		(S390_lowcore.machine_flags & MACHINE_FLAG_VM)
 #define MACHINE_IS_KVM		(S390_lowcore.machine_flags & MACHINE_FLAG_KVM)
···
 #define MACHINE_HAS_PFMF	(0)
 #define MACHINE_HAS_SPP		(0)
 #define MACHINE_HAS_TOPOLOGY	(0)
-#define MACHINE_HAS_STCKF	(0)
 #else /* __s390x__ */
 #define MACHINE_HAS_IEEE	(1)
 #define MACHINE_HAS_CSP		(1)
···
 #define MACHINE_HAS_PFMF	(S390_lowcore.machine_flags & MACHINE_FLAG_PFMF)
 #define MACHINE_HAS_SPP		(S390_lowcore.machine_flags & MACHINE_FLAG_SPP)
 #define MACHINE_HAS_TOPOLOGY	(S390_lowcore.machine_flags & MACHINE_FLAG_TOPOLOGY)
-#define MACHINE_HAS_STCKF	(S390_lowcore.machine_flags & MACHINE_FLAG_STCKF)
 #endif /* __s390x__ */
 
 #define ZFCPDUMP_HSA_SIZE	(32UL<<20)

arch/s390/include/asm/timex.h

···
 
 typedef unsigned long long cycles_t;
 
-static inline unsigned long long get_clock (void)
+static inline unsigned long long get_clock(void)
 {
 	unsigned long long clk;
 
+#if defined(CONFIG_64BIT) && !defined(CONFIG_MARCH_Z900) && !defined(CONFIG_MARCH_Z990)
+	asm volatile(".insn s,0xb27c0000,%0" : "=Q" (clk) : : "cc");
+#else
 	asm volatile("stck %0" : "=Q" (clk) : : "cc");
+#endif
 	return clk;
 }
 
 static inline void get_clock_ext(char *clk)
 {
 	asm volatile("stcke %0" : "=Q" (*clk) : : "cc");
-}
-
-static inline unsigned long long get_clock_fast(void)
-{
-	unsigned long long clk;
-
-	if (MACHINE_HAS_STCKF)
-		asm volatile(".insn	s,0xb27c0000,%0" : "=Q" (clk) : : "cc");
-	else
-		clk = get_clock();
-	return clk;
 }
 
 static inline unsigned long long get_clock_xt(void)

arch/s390/kernel/early.c

···
 		S390_lowcore.machine_flags |= MACHINE_FLAG_MVCOS;
 	if (test_facility(40))
 		S390_lowcore.machine_flags |= MACHINE_FLAG_SPP;
-	if (test_facility(25))
-		S390_lowcore.machine_flags |= MACHINE_FLAG_STCKF;
 #endif
 }
 

arch/s390/kernel/entry64.S

···
 	ssm	__LC_RETURN_PSW
 	.endm
 
+	.macro STCK savearea
+#if defined(CONFIG_64BIT) && !defined(CONFIG_MARCH_Z900) && !defined(CONFIG_MARCH_Z990)
+	.insn	s,0xb27c0000,\savearea		# store clock fast
+#else
+	.insn	s,0xb2050000,\savearea		# store clock
+#endif
+	.endm
+
 	.section .kprobes.text, "ax"
 
 /*
···
  * IO interrupt handler routine
  */
 ENTRY(io_int_handler)
-	stck	__LC_INT_CLOCK
+	STCK	__LC_INT_CLOCK
 	stpt	__LC_ASYNC_ENTER_TIMER
 	stmg	%r8,%r15,__LC_SAVE_AREA_ASYNC
 	lg	%r10,__LC_LAST_BREAK
···
  * External interrupt handler routine
  */
 ENTRY(ext_int_handler)
-	stck	__LC_INT_CLOCK
+	STCK	__LC_INT_CLOCK
 	stpt	__LC_ASYNC_ENTER_TIMER
 	stmg	%r8,%r15,__LC_SAVE_AREA_ASYNC
 	lg	%r10,__LC_LAST_BREAK
···
 	larl	%r1,psw_idle_lpsw+4
 	stg	%r1,__SF_EMPTY+8(%r15)
 	larl	%r1,.Lvtimer_max
-	stck	__IDLE_ENTER(%r2)
+	STCK	__IDLE_ENTER(%r2)
 	ltr	%r5,%r5
 	stpt	__VQ_IDLE_ENTER(%r3)
 	jz	psw_idle_lpsw
···
  * Machine check handler routines
  */
 ENTRY(mcck_int_handler)
-	stck	__LC_MCCK_CLOCK
+	STCK	__LC_MCCK_CLOCK
 	la	%r1,4095		# revalidate r1
 	spt	__LC_CPU_TIMER_SAVE_AREA-4095(%r1)	# revalidate cpu timer
 	lmg	%r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# revalidate gprs

drivers/s390/cio/qdio_main.c

···
 	int count, stop;
 	unsigned char state = 0;
 
-	q->timestamp = get_clock_fast();
+	q->timestamp = get_clock();
 
 	/*
 	 * Don't check 128 buffers, as otherwise qdio_inbound_q_moved
···
 	int count, stop;
 	unsigned char state = 0;
 
-	q->timestamp = get_clock_fast();
+	q->timestamp = get_clock();
 
 	if (need_siga_sync(q))
 		if (((queue_type(q) != QDIO_IQDIO_QFMT) &&