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: Vasily Gorbik <gor@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 09e783d..709cb6c 100644 (file)
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -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");

diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index 43b0d46..9205031 100644 (file)
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -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)