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s390/spinlock: use cpu alternatives to enable niai instruction

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

Signed-off-by: Vasily Gorbik <gor@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Vasily Gorbik 2017-10-12 13:01:47 +02:00 committed by Martin Schwidefsky
parent 686140a1a9
commit f554be42fd
2 changed files with 5 additions and 9 deletions
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5
arch/s390/include/asm/spinlock.h
View File

@ -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");

9
arch/s390/lib/spinlock.c
View File

@ -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)