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authorPeter Zijlstra <peterz@infradead.org>2016-04-18 01:16:04 +0200
committerIngo Molnar <mingo@kernel.org>2016-06-16 10:48:30 +0200
commit3a1adb23a52c920304239efff377d3bc967febc2 (patch)
tree63383d193b7a7adaec40939daac2cdd22326108a /arch/sparc/lib
parentlocking/atomic, arch/sh: Implement atomic_fetch_{add,sub,and,or,xor}() (diff)
downloadlinux-dev-3a1adb23a52c920304239efff377d3bc967febc2.tar.xz
linux-dev-3a1adb23a52c920304239efff377d3bc967febc2.zip
locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: James Y Knight <jyknight@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: sparclinux@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/sparc/lib')
-rw-r--r--arch/sparc/lib/atomic32.c29
-rw-r--r--arch/sparc/lib/atomic_64.S61
-rw-r--r--arch/sparc/lib/ksyms.c17
3 files changed, 80 insertions, 27 deletions
diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c
index b9d63c0a7aab..2c373329d5cb 100644
--- a/arch/sparc/lib/atomic32.c
+++ b/arch/sparc/lib/atomic32.c
@@ -27,39 +27,44 @@ static DEFINE_SPINLOCK(dummy);
#endif /* SMP */
-#define ATOMIC_OP_RETURN(op, c_op) \
-int atomic_##op##_return(int i, atomic_t *v) \
+#define ATOMIC_FETCH_OP(op, c_op) \
+int atomic_fetch_##op(int i, atomic_t *v) \
{ \
int ret; \
unsigned long flags; \
spin_lock_irqsave(ATOMIC_HASH(v), flags); \
\
- ret = (v->counter c_op i); \
+ ret = v->counter; \
+ v->counter c_op i; \
\
spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \
return ret; \
} \
-EXPORT_SYMBOL(atomic_##op##_return);
+EXPORT_SYMBOL(atomic_fetch_##op);
-#define ATOMIC_OP(op, c_op) \
-void atomic_##op(int i, atomic_t *v) \
+#define ATOMIC_OP_RETURN(op, c_op) \
+int atomic_##op##_return(int i, atomic_t *v) \
{ \
+ int ret; \
unsigned long flags; \
spin_lock_irqsave(ATOMIC_HASH(v), flags); \
\
- v->counter c_op i; \
+ ret = (v->counter c_op i); \
\
spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \
+ return ret; \
} \
-EXPORT_SYMBOL(atomic_##op);
+EXPORT_SYMBOL(atomic_##op##_return);
ATOMIC_OP_RETURN(add, +=)
-ATOMIC_OP(and, &=)
-ATOMIC_OP(or, |=)
-ATOMIC_OP(xor, ^=)
+ATOMIC_FETCH_OP(add, +=)
+ATOMIC_FETCH_OP(and, &=)
+ATOMIC_FETCH_OP(or, |=)
+ATOMIC_FETCH_OP(xor, ^=)
+
+#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
-#undef ATOMIC_OP
int atomic_xchg(atomic_t *v, int new)
{
diff --git a/arch/sparc/lib/atomic_64.S b/arch/sparc/lib/atomic_64.S
index d6b0363f345b..a5c5a0279ccc 100644
--- a/arch/sparc/lib/atomic_64.S
+++ b/arch/sparc/lib/atomic_64.S
@@ -9,10 +9,11 @@
.text
- /* Two versions of the atomic routines, one that
+ /* Three versions of the atomic routines, one that
* does not return a value and does not perform
- * memory barriers, and a second which returns
- * a value and does the barriers.
+ * memory barriers, and a two which return
+ * a value, the new and old value resp. and does the
+ * barriers.
*/
#define ATOMIC_OP(op) \
@@ -43,15 +44,34 @@ ENTRY(atomic_##op##_return) /* %o0 = increment, %o1 = atomic_ptr */ \
2: BACKOFF_SPIN(%o2, %o3, 1b); \
ENDPROC(atomic_##op##_return);
-#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)
+#define ATOMIC_FETCH_OP(op) \
+ENTRY(atomic_fetch_##op) /* %o0 = increment, %o1 = atomic_ptr */ \
+ BACKOFF_SETUP(%o2); \
+1: lduw [%o1], %g1; \
+ op %g1, %o0, %g7; \
+ cas [%o1], %g1, %g7; \
+ cmp %g1, %g7; \
+ bne,pn %icc, BACKOFF_LABEL(2f, 1b); \
+ nop; \
+ retl; \
+ sra %g1, 0, %o0; \
+2: BACKOFF_SPIN(%o2, %o3, 1b); \
+ENDPROC(atomic_fetch_##op);
+
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
ATOMIC_OPS(add)
ATOMIC_OPS(sub)
-ATOMIC_OP(and)
-ATOMIC_OP(or)
-ATOMIC_OP(xor)
#undef ATOMIC_OPS
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
+
+ATOMIC_OPS(and)
+ATOMIC_OPS(or)
+ATOMIC_OPS(xor)
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP
@@ -83,15 +103,34 @@ ENTRY(atomic64_##op##_return) /* %o0 = increment, %o1 = atomic_ptr */ \
2: BACKOFF_SPIN(%o2, %o3, 1b); \
ENDPROC(atomic64_##op##_return);
-#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op)
+#define ATOMIC64_FETCH_OP(op) \
+ENTRY(atomic64_fetch_##op) /* %o0 = increment, %o1 = atomic_ptr */ \
+ BACKOFF_SETUP(%o2); \
+1: ldx [%o1], %g1; \
+ op %g1, %o0, %g7; \
+ casx [%o1], %g1, %g7; \
+ cmp %g1, %g7; \
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b); \
+ nop; \
+ retl; \
+ mov %g1, %o0; \
+2: BACKOFF_SPIN(%o2, %o3, 1b); \
+ENDPROC(atomic64_fetch_##op);
+
+#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op)
ATOMIC64_OPS(add)
ATOMIC64_OPS(sub)
-ATOMIC64_OP(and)
-ATOMIC64_OP(or)
-ATOMIC64_OP(xor)
#undef ATOMIC64_OPS
+#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_FETCH_OP(op)
+
+ATOMIC64_OPS(and)
+ATOMIC64_OPS(or)
+ATOMIC64_OPS(xor)
+
+#undef ATOMIC64_OPS
+#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
diff --git a/arch/sparc/lib/ksyms.c b/arch/sparc/lib/ksyms.c
index 8eb454cfe05c..de5e97817bdb 100644
--- a/arch/sparc/lib/ksyms.c
+++ b/arch/sparc/lib/ksyms.c
@@ -107,15 +107,24 @@ EXPORT_SYMBOL(atomic64_##op);
EXPORT_SYMBOL(atomic_##op##_return); \
EXPORT_SYMBOL(atomic64_##op##_return);
-#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op)
+#define ATOMIC_FETCH_OP(op) \
+EXPORT_SYMBOL(atomic_fetch_##op); \
+EXPORT_SYMBOL(atomic64_fetch_##op);
+
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
ATOMIC_OPS(add)
ATOMIC_OPS(sub)
-ATOMIC_OP(and)
-ATOMIC_OP(or)
-ATOMIC_OP(xor)
#undef ATOMIC_OPS
+#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
+
+ATOMIC_OPS(and)
+ATOMIC_OPS(or)
+ATOMIC_OPS(xor)
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP