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authorPeter Zijlstra <peterz@infradead.org>2017-06-09 13:05:06 +0200
committerIngo Molnar <mingo@kernel.org>2017-08-10 12:28:54 +0200
commit9d664c0aec3bfdb77fcf7de61cfe1febbecdd389 (patch)
tree58c96472de25e0ebcbf2f47b7a53d262edcb3e94 /arch
parent35a2897c2a306cca344ca5c0b43416707018f434 (diff)
locking/atomic: Fix atomic_set_release() for 'funny' architectures
Those architectures that have a special atomic_set implementation also need a special atomic_set_release(), because for the very same reason WRITE_ONCE() is broken for them, smp_store_release() is too. The vast majority is architectures that have spinlock hash based atomic implementation except hexagon which seems to have a hardware 'feature'. The spinlock based atomics should be SC, that is, none of them appear to place extra barriers in atomic_cmpxchg() or any of the other SC atomic primitives and therefore seem to rely on their spinlock implementation being SC (I did not fully validate all that). Therefore, the normal atomic_set() is SC and can be used at atomic_set_release(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile] Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: davem@davemloft.net Cc: james.hogan@imgtec.com Cc: jejb@parisc-linux.org Cc: rkuo@codeaurora.org Cc: vgupta@synopsys.com Link: http://lkml.kernel.org/r/20170609110506.yod47flaav3wgoj5@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arc/include/asm/atomic.h2
-rw-r--r--arch/hexagon/include/asm/atomic.h2
-rw-r--r--arch/metag/include/asm/atomic_lock1.h2
-rw-r--r--arch/parisc/include/asm/atomic.h2
-rw-r--r--arch/sparc/include/asm/atomic_32.h2
-rw-r--r--arch/tile/include/asm/atomic_32.h2
6 files changed, 12 insertions, 0 deletions
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index 54b54da6384c..11859287c52a 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -123,6 +123,8 @@ static inline void atomic_set(atomic_t *v, int i)
atomic_ops_unlock(flags);
}
+#define atomic_set_release(v, i) atomic_set((v), (i))
+
#endif
/*
diff --git a/arch/hexagon/include/asm/atomic.h b/arch/hexagon/include/asm/atomic.h
index a62ba368b27d..fb3dfb2a667e 100644
--- a/arch/hexagon/include/asm/atomic.h
+++ b/arch/hexagon/include/asm/atomic.h
@@ -42,6 +42,8 @@ static inline void atomic_set(atomic_t *v, int new)
);
}
+#define atomic_set_release(v, i) atomic_set((v), (i))
+
/**
* atomic_read - reads a word, atomically
* @v: pointer to atomic value
diff --git a/arch/metag/include/asm/atomic_lock1.h b/arch/metag/include/asm/atomic_lock1.h
index 6c1380a8a0d4..eee779f26cc4 100644
--- a/arch/metag/include/asm/atomic_lock1.h
+++ b/arch/metag/include/asm/atomic_lock1.h
@@ -37,6 +37,8 @@ static inline int atomic_set(atomic_t *v, int i)
return i;
}
+#define atomic_set_release(v, i) atomic_set((v), (i))
+
#define ATOMIC_OP(op, c_op) \
static inline void atomic_##op(int i, atomic_t *v) \
{ \
diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h
index 5394b9c5f914..17b98a87e5e2 100644
--- a/arch/parisc/include/asm/atomic.h
+++ b/arch/parisc/include/asm/atomic.h
@@ -65,6 +65,8 @@ static __inline__ void atomic_set(atomic_t *v, int i)
_atomic_spin_unlock_irqrestore(v, flags);
}
+#define atomic_set_release(v, i) atomic_set((v), (i))
+
static __inline__ int atomic_read(const atomic_t *v)
{
return READ_ONCE((v)->counter);
diff --git a/arch/sparc/include/asm/atomic_32.h b/arch/sparc/include/asm/atomic_32.h
index ee3f11c43cda..7643e979e333 100644
--- a/arch/sparc/include/asm/atomic_32.h
+++ b/arch/sparc/include/asm/atomic_32.h
@@ -29,6 +29,8 @@ int atomic_xchg(atomic_t *, int);
int __atomic_add_unless(atomic_t *, int, int);
void atomic_set(atomic_t *, int);
+#define atomic_set_release(v, i) atomic_set((v), (i))
+
#define atomic_read(v) ACCESS_ONCE((v)->counter)
#define atomic_add(i, v) ((void)atomic_add_return( (int)(i), (v)))
diff --git a/arch/tile/include/asm/atomic_32.h b/arch/tile/include/asm/atomic_32.h
index a93774255136..53a423e7cb92 100644
--- a/arch/tile/include/asm/atomic_32.h
+++ b/arch/tile/include/asm/atomic_32.h
@@ -101,6 +101,8 @@ static inline void atomic_set(atomic_t *v, int n)
_atomic_xchg(&v->counter, n);
}
+#define atomic_set_release(v, i) atomic_set((v), (i))
+
/* A 64bit atomic type */
typedef struct {