[RFC][PATCH 30/31] locking,mips: Convert to _relaxed atomics

From: Peter Zijlstra
Date: Fri Apr 22 2016 - 05:44:55 EST


Generic code will construct {,_acquire,_release} versions by adding the
required smp_mb__{before,after}_atomic() calls.

XXX if/when MIPS will start using their new SYNCxx instructions they
can provide custom __atomic_op_{acquire,release}() macros as per the
powerpc example.


Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/mips/include/asm/atomic.h | 42 +++++++++++++++++++++--------------------
1 file changed, 22 insertions(+), 20 deletions(-)

--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -79,12 +79,10 @@ static __inline__ void atomic_##op(int i
}

#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
-static __inline__ int atomic_##op##_return(int i, atomic_t * v) \
+static __inline__ int atomic_##op##_return_relaxed(int i, atomic_t * v) \
{ \
int result; \
\
- smp_mb__before_llsc(); \
- \
if (kernel_uses_llsc && R10000_LLSC_WAR) { \
int temp; \
\
@@ -125,18 +123,14 @@ static __inline__ int atomic_##op##_retu
raw_local_irq_restore(flags); \
} \
\
- smp_llsc_mb(); \
- \
return result; \
}

#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
-static __inline__ int atomic_fetch_##op(int i, atomic_t * v) \
+static __inline__ int atomic_fetch_##op##_relaxed(int i, atomic_t * v) \
{ \
int result; \
\
- smp_mb__before_llsc(); \
- \
if (kernel_uses_llsc && R10000_LLSC_WAR) { \
int temp; \
\
@@ -176,8 +170,6 @@ static __inline__ int atomic_fetch_##op(
raw_local_irq_restore(flags); \
} \
\
- smp_llsc_mb(); \
- \
return result; \
}

@@ -189,6 +181,11 @@ static __inline__ int atomic_fetch_##op(
ATOMIC_OPS(add, +=, addu)
ATOMIC_OPS(sub, -=, subu)

+#define atomic_add_return_relaxed atomic_add_return_relaxed
+#define atomic_sub_return_relaxed atomic_sub_return_relaxed
+#define atomic_fetch_add_relaxed atomic_fetch_add_relaxed
+#define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed
+
#undef ATOMIC_OPS
#define ATOMIC_OPS(op, c_op, asm_op) \
ATOMIC_OP(op, c_op, asm_op) \
@@ -198,6 +195,10 @@ ATOMIC_OPS(and, &=, and)
ATOMIC_OPS(or, |=, or)
ATOMIC_OPS(xor, ^=, xor)

+#define atomic_fetch_and_relaxed atomic_fetch_and_relaxed
+#define atomic_fetch_or_relaxed atomic_fetch_or_relaxed
+#define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed
+
#undef ATOMIC_OPS
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
@@ -420,12 +421,10 @@ static __inline__ void atomic64_##op(lon
}

#define ATOMIC64_OP_RETURN(op, c_op, asm_op) \
-static __inline__ long atomic64_##op##_return(long i, atomic64_t * v) \
+static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \
{ \
long result; \
\
- smp_mb__before_llsc(); \
- \
if (kernel_uses_llsc && R10000_LLSC_WAR) { \
long temp; \
\
@@ -467,18 +466,14 @@ static __inline__ long atomic64_##op##_r
raw_local_irq_restore(flags); \
} \
\
- smp_llsc_mb(); \
- \
return result; \
}

#define ATOMIC64_FETCH_OP(op, c_op, asm_op) \
-static __inline__ long atomic64_fetch_##op(long i, atomic64_t * v) \
+static __inline__ long atomic64_fetch_##op##_relaxed(long i, atomic64_t * v) \
{ \
long result; \
\
- smp_mb__before_llsc(); \
- \
if (kernel_uses_llsc && R10000_LLSC_WAR) { \
long temp; \
\
@@ -519,8 +514,6 @@ static __inline__ long atomic64_fetch_##
raw_local_irq_restore(flags); \
} \
\
- smp_llsc_mb(); \
- \
return result; \
}

@@ -532,6 +525,11 @@ static __inline__ long atomic64_fetch_##
ATOMIC64_OPS(add, +=, daddu)
ATOMIC64_OPS(sub, -=, dsubu)

+#define atomic64_add_return_relaxed atomic64_add_return_relaxed
+#define atomic64_sub_return_relaxed atomic64_sub_return_relaxed
+#define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed
+#define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed
+
#undef ATOMIC64_OPS
#define ATOMIC64_OPS(op, c_op, asm_op) \
ATOMIC64_OP(op, c_op, asm_op) \
@@ -541,6 +539,10 @@ ATOMIC64_OPS(and, &=, and)
ATOMIC64_OPS(or, |=, or)
ATOMIC64_OPS(xor, ^=, xor)

+#define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed
+#define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed
+#define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed
+
#undef ATOMIC64_OPS
#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN