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authorMaxim Kuvyrkov <maxim@kugelworks.com>2013-09-19 18:50:17 +1200
committerMaxim Kuvyrkov <maxim@kugelworks.com>2013-09-19 18:50:17 +1200
commitd70d6205fabf863ce18e53d49f9d83f5f16c5fee (patch)
treecae7e89c8d5e2d01b99338ff876fd05b38cde160 /ports
parent9c21573c02446b3d5cf6a34b67c8545e5be6a600 (diff)
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Improve atomic locking for ARM.
[BZ #15640] * sysdeps/arm/bits/atomic.h (atomic_exchange_acq, atomic_exchange_rel) (atomic_compare_and_exchange_bool_acq) (atomic_compare_and_exchange_val_acq) (atomic_compare_and_exchange_bool_rel) (atomic_compare_and_exchange_val_rel): Use __atomic_exchange_n and __atomic_compare_exchange_n builtins when GCC supports them.
Diffstat (limited to 'ports')
-rw-r--r--ports/ChangeLog.arm10
-rw-r--r--ports/sysdeps/arm/bits/atomic.h94
2 files changed, 96 insertions, 8 deletions
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 35f6f77..bff557c 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,3 +1,13 @@
+2013-09-18 Dinar Temirbulatov <dtemirbulatov@gmail.com>
+
+ [BZ #15640]
+ * sysdeps/arm/bits/atomic.h (atomic_exchange_acq, atomic_exchange_rel)
+ (atomic_compare_and_exchange_bool_acq)
+ (atomic_compare_and_exchange_val_acq)
+ (atomic_compare_and_exchange_bool_rel)
+ (atomic_compare_and_exchange_val_rel): Use __atomic_exchange_n and
+ __atomic_compare_exchange_n builtins when GCC supports them.
+
2013-09-16 Will Newton <will.newton@linaro.org>
* sysdeps/arm/armv7/multiarch/memcpy_impl.S: Tighten check
diff --git a/ports/sysdeps/arm/bits/atomic.h b/ports/sysdeps/arm/bits/atomic.h
index 6e20df7..5e0801d 100644
--- a/ports/sysdeps/arm/bits/atomic.h
+++ b/ports/sysdeps/arm/bits/atomic.h
@@ -35,9 +35,6 @@ typedef uintmax_t uatomic_max_t;
void __arm_link_error (void);
-/* Use the atomic builtins provided by GCC in case the backend provides
- a pattern to do this efficiently. */
-
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
# define atomic_full_barrier() __sync_synchronize ()
#else
@@ -51,9 +48,88 @@ void __arm_link_error (void);
# define __arm_assisted_full_barrier() __arm_link_error()
#endif
-/* Atomic compare and exchange. */
+/* Use the atomic builtins provided by GCC in case the backend provides
+ a pattern to do this efficiently. */
+#if __GNUC_PREREQ (4, 7) && defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
-#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+# define atomic_exchange_acq(mem, value) \
+ __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_ACQUIRE)
+
+# define atomic_exchange_rel(mem, value) \
+ __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_RELEASE)
+
+/* Atomic exchange (without compare). */
+
+# define __arch_exchange_8_int(mem, newval, model) \
+ (__arm_link_error (), (typeof (*mem)) 0)
+
+# define __arch_exchange_16_int(mem, newval, model) \
+ (__arm_link_error (), (typeof (*mem)) 0)
+
+# define __arch_exchange_32_int(mem, newval, model) \
+ __atomic_exchange_n (mem, newval, model)
+
+# define __arch_exchange_64_int(mem, newval, model) \
+ (__arm_link_error (), (typeof (*mem)) 0)
+
+/* Compare and exchange with "acquire" semantics, ie barrier after. */
+
+# define atomic_compare_and_exchange_bool_acq(mem, new, old) \
+ __atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \
+ mem, new, old, __ATOMIC_ACQUIRE)
+
+# define atomic_compare_and_exchange_val_acq(mem, new, old) \
+ __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
+ mem, new, old, __ATOMIC_ACQUIRE)
+
+/* Compare and exchange with "release" semantics, ie barrier before. */
+
+# define atomic_compare_and_exchange_bool_rel(mem, new, old) \
+ __atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \
+ mem, new, old, __ATOMIC_RELEASE)
+
+# define atomic_compare_and_exchange_val_rel(mem, new, old) \
+ __atomic_val_bysize (__arch_compare_and_exchange_val, int, \
+ mem, new, old, __ATOMIC_RELEASE)
+
+/* Compare and exchange.
+ For all "bool" routines, we return FALSE if exchange succesful. */
+
+# define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_bool_32_int(mem, newval, oldval, model) \
+ ({ \
+ typeof (*mem) __oldval = (oldval); \
+ !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
+ model, __ATOMIC_RELAXED); \
+ })
+
+# define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+# define __arch_compare_and_exchange_val_32_int(mem, newval, oldval, model) \
+ ({ \
+ typeof (*mem) __oldval = (oldval); \
+ __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \
+ model, __ATOMIC_RELAXED); \
+ __oldval; \
+ })
+
+# define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
+ ({__arm_link_error (); oldval; })
+
+#elif defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+/* Atomic compare and exchange. */
# define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
__sync_val_compare_and_swap ((mem), (oldval), (newval))
#else
@@ -61,16 +137,18 @@ void __arm_link_error (void);
__arm_assisted_compare_and_exchange_val_32_acq ((mem), (newval), (oldval))
#endif
+#if !__GNUC_PREREQ (4, 7) || !defined (__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
/* We don't support atomic operations on any non-word types.
So make them link errors. */
-#define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
+# define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
-#define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
+# define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
-#define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
+# define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
+#endif
/* An OS-specific bits/atomic.h file will define this macro if
the OS can provide something. If not, we'll fail to build