From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Use compare double and swap to implement efficient atomic64 ops for 31 bit.
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
arch/s390/Kconfig | 1
arch/s390/include/asm/atomic.h | 164 +++++++++++++++++++++++++++++++----------
2 files changed, 127 insertions(+), 38 deletions(-)
Index: quilt-2.6/arch/s390/include/asm/atomic.h
===================================================================
--- quilt-2.6.orig/arch/s390/include/asm/atomic.h
+++ quilt-2.6/arch/s390/include/asm/atomic.h
@@ -1,28 +1,20 @@
#ifndef __ARCH_S390_ATOMIC__
#define __ARCH_S390_ATOMIC__
-#include <linux/compiler.h>
-#include <linux/types.h>
-
/*
- * include/asm-s390/atomic.h
+ * Copyright 1999,2009 IBM Corp.
+ * Author(s): Martin Schwidefsky <schwidefsky@xxxxxxxxxx>,
+ * Denis Joseph Barrow,
+ * Arnd Bergmann <arndb@xxxxxxxxxx>,
*
- * S390 version
- * Copyright (C) 1999-2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
- * Author(s): Martin Schwidefsky (schwidefsky@xxxxxxxxxx),
- * Denis Joseph Barrow,
- * Arnd Bergmann (arndb@xxxxxxxxxx)
- *
- * Derived from "include/asm-i386/bitops.h"
- * Copyright (C) 1992, Linus Torvalds
+ * Atomic operations that C can't guarantee us.
+ * Useful for resource counting etc.
+ * s390 uses 'Compare And Swap' for atomicity in SMP enviroment.
*
*/
-/*
- * Atomic operations that C can't guarantee us. Useful for
- * resource counting etc..
- * S390 uses 'Compare And Swap' for atomicity in SMP enviroment
- */
+#include <linux/compiler.h>
+#include <linux/types.h>
#define ATOMIC_INIT(i) { (i) }
@@ -146,9 +138,10 @@ static __inline__ int atomic_add_unless(
#undef __CS_LOOP
-#ifdef __s390x__
#define ATOMIC64_INIT(i) { (i) }
+#ifdef CONFIG_64BIT
+
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
#define __CSG_LOOP(ptr, op_val, op_string) ({ \
@@ -202,21 +195,11 @@ static __inline__ long long atomic64_add
{
return __CSG_LOOP(v, i, "agr");
}
-#define atomic64_add(_i, _v) atomic64_add_return(_i, _v)
-#define atomic64_add_negative(_i, _v) (atomic64_add_return(_i, _v) < 0)
-#define atomic64_inc(_v) atomic64_add_return(1, _v)
-#define atomic64_inc_return(_v) atomic64_add_return(1, _v)
-#define atomic64_inc_and_test(_v) (atomic64_add_return(1, _v) == 0)
static __inline__ long long atomic64_sub_return(long long i, atomic64_t * v)
{
return __CSG_LOOP(v, i, "sgr");
}
-#define atomic64_sub(_i, _v) atomic64_sub_return(_i, _v)
-#define atomic64_sub_and_test(_i, _v) (atomic64_sub_return(_i, _v) == 0)
-#define atomic64_dec(_v) atomic64_sub_return(1, _v)
-#define atomic64_dec_return(_v) atomic64_sub_return(1, _v)
-#define atomic64_dec_and_test(_v) (atomic64_sub_return(1, _v) == 0)
static __inline__ void atomic64_clear_mask(unsigned long mask, atomic64_t * v)
{
@@ -249,6 +232,111 @@ static __inline__ long long atomic64_cmp
return old;
}
+#undef __CSG_LOOP
+
+#else /* CONFIG_64BIT */
+
+typedef struct {
+ long long counter;
+} atomic64_t;
+
+static inline long long atomic64_read(const atomic64_t *v)
+{
+ register_pair rp;
+
+ asm volatile(
+ " lm %0,%N0,0(%1)"
+ : "=&d" (rp)
+ : "a" (&v->counter), "m" (v->counter)
+ );
+ return rp.pair;
+}
+
+static inline void atomic64_set(atomic64_t *v, long long i)
+{
+ register_pair rp = {.pair = i};
+
+ asm volatile(
+ " stm %1,%N1,0(%2)"
+ : "=m" (v->counter)
+ : "d" (rp), "a" (&v->counter)
+ );
+}
+
+static inline long long atomic64_xchg(atomic64_t *v, long long new)
+{
+ register_pair rp_new = {.pair = new};
+ register_pair rp_old;
+
+ asm volatile(
+ " lm %0,%N0,0(%2)\n"
+ "0: cds %0,%3,0(%2)\n"
+ " jl 0b\n"
+ : "=&d" (rp_old), "+m" (v->counter)
+ : "a" (&v->counter), "d" (rp_new)
+ : "cc");
+ return rp_old.pair;
+}
+
+static inline long long atomic64_cmpxchg(atomic64_t *v,
+ long long old, long long new)
+{
+ register_pair rp_old = {.pair = old};
+ register_pair rp_new = {.pair = new};
+
+ asm volatile(
+ " cds %0,%3,0(%2)"
+ : "+&d" (rp_old), "+m" (v->counter)
+ : "a" (&v->counter), "d" (rp_new)
+ : "cc");
+ return rp_old.pair;
+}
+
+
+static inline long long atomic64_add_return(long long i, atomic64_t *v)
+{
+ long long old, new;
+
+ do {
+ old = atomic64_read(v);
+ new = old + i;
+ } while (atomic64_cmpxchg(v, old, new) != old);
+ return new;
+}
+
+static inline long long atomic64_sub_return(long long i, atomic64_t *v)
+{
+ long long old, new;
+
+ do {
+ old = atomic64_read(v);
+ new = old - i;
+ } while (atomic64_cmpxchg(v, old, new) != old);
+ return new;
+}
+
+static inline void atomic64_set_mask(unsigned long long mask, atomic64_t *v)
+{
+ long long old, new;
+
+ do {
+ old = atomic64_read(v);
+ new = old | mask;
+ } while (atomic64_cmpxchg(v, old, new) != old);
+}
+
+static inline void atomic64_clear_mask(unsigned long long mask, atomic64_t *v)
+{
+ long long old, new;
+
+ do {
+ old = atomic64_read(v);
+ new = old & mask;
+ } while (atomic64_cmpxchg(v, old, new) != old);
+}
+
+#endif /* CONFIG_64BIT */
+
static __inline__ int atomic64_add_unless(atomic64_t *v,
long long a, long long u)
{
@@ -265,15 +353,17 @@ static __inline__ int atomic64_add_unles
return c != u;
}
-#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
-
-#undef __CSG_LOOP
-
-#else /* __s390x__ */
-
-#include <asm-generic/atomic64.h>
-
-#endif /* __s390x__ */
+#define atomic64_add(_i, _v) atomic64_add_return(_i, _v)
+#define atomic64_add_negative(_i, _v) (atomic64_add_return(_i, _v) < 0)
+#define atomic64_inc(_v) atomic64_add_return(1, _v)
+#define atomic64_inc_return(_v) atomic64_add_return(1, _v)
+#define atomic64_inc_and_test(_v) (atomic64_add_return(1, _v) == 0)
+#define atomic64_sub(_i, _v) atomic64_sub_return(_i, _v)
+#define atomic64_sub_and_test(_i, _v) (atomic64_sub_return(_i, _v) == 0)
+#define atomic64_dec(_v) atomic64_sub_return(1, _v)
+#define atomic64_dec_return(_v) atomic64_sub_return(1, _v)
+#define atomic64_dec_and_test(_v) (atomic64_sub_return(1, _v) == 0)
+#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec() smp_mb()
Index: quilt-2.6/arch/s390/Kconfig
===================================================================
--- quilt-2.6.orig/arch/s390/Kconfig
+++ quilt-2.6/arch/s390/Kconfig
@@ -95,7 +95,6 @@ config S390
select HAVE_ARCH_TRACEHOOK
select INIT_ALL_POSSIBLE
select HAVE_PERF_COUNTERS
- select GENERIC_ATOMIC64 if !64BIT
config SCHED_OMIT_FRAME_POINTER
bool
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
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