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Commit f554be42 authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Martin Schwidefsky
Browse files

s390/spinlock: use cpu alternatives to enable niai instruction 



Enable niai instruction in the spinlock code at run-time for machines
on which facility 49 is available (zEC12 and newer).

Signed-off-by: default avatarVasily Gorbik <gor@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 686140a1

arch/s390/include/asm/spinlock.h

+2 −3
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <asm/atomic_ops.h>

#include <asm/barrier.h>

#include <asm/processor.h>

#include <asm/alternative.h>



#define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval)
@@ -86,9 +87,7 @@ static inline void arch_spin_unlock(arch_spinlock_t *lp) 
{

	typecheck(int, lp->lock);

	asm volatile(

#ifdef CONFIG_HAVE_MARCH_ZEC12_FEATURES

		"	.long	0xb2fa0070\n"	/* NIAI 7 */

#endif

		ALTERNATIVE("", ".long 0xb2fa0070", 49)	/* NIAI 7 */

		"	sth	%1,%0\n"

		: "=Q" (((unsigned short *) &lp->lock)[1])

		: "d" (0) : "cc", "memory");

arch/s390/lib/spinlock.c

+3 −6
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/init.h>

#include <linux/smp.h>

#include <linux/percpu.h>

#include <asm/alternative.h>

#include <asm/io.h>



int spin_retry = -1;
@@ -73,9 +74,7 @@ static inline int arch_load_niai4(int *lock) 
	int owner;



	asm volatile(

#ifdef CONFIG_HAVE_MARCH_ZEC12_FEATURES

		"	.long	0xb2fa0040\n"	/* NIAI 4 */

#endif

		ALTERNATIVE("", ".long 0xb2fa0040", 49)	/* NIAI 4 */

		"	l	%0,%1\n"

		: "=d" (owner) : "Q" (*lock) : "memory");

       return owner;
@@ -86,9 +85,7 @@ static inline int arch_cmpxchg_niai8(int *lock, int old, int new) 
	int expected = old;



	asm volatile(

#ifdef CONFIG_HAVE_MARCH_ZEC12_FEATURES

		"	.long	0xb2fa0080\n"	/* NIAI 8 */

#endif

		ALTERNATIVE("", ".long 0xb2fa0080", 49)	/* NIAI 8 */

		"	cs	%0,%3,%1\n"

		: "=d" (old), "=Q" (*lock)

		: "0" (old), "d" (new), "Q" (*lock)