[dpdk-dev] [PATCH v5 01/15] eal/arm: atomic operations for ARM

[Jan Viktorin <viktorin@rehivetech.com>]

From: Vlastimil Kosar <kosar@rehivetech.com>

This patch adds architecture specific atomic operation file
for ARM architecture. It utilizes compiler intrinsics only.

Signed-off-by: Vlastimil Kosar <kosar@rehivetech.com>
Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
---
v1 -> v2:
* improve rte_wmb()
* use __atomic_* or __sync_*? (may affect the required GCC version)

v4:
* checkpatch complaints about volatile keyword (but seems to be OK to me)
* checkpatch complaints about do { ... } while (0) for single statement
  with asm volatile (but I didn't find a way how to write it without
  the checkpatch complaints)
* checkpatch is now happy with whitespaces
---
 .../common/include/arch/arm/rte_atomic.h           | 256 +++++++++++++++++++++
 1 file changed, 256 insertions(+)
 create mode 100644 lib/librte_eal/common/include/arch/arm/rte_atomic.h

diff --git a/lib/librte_eal/common/include/arch/arm/rte_atomic.h b/lib/librte_eal/common/include/arch/arm/rte_atomic.h
new file mode 100644
index 0000000..ea1e485
--- /dev/null
+++ b/lib/librte_eal/common/include/arch/arm/rte_atomic.h
@@ -0,0 +1,256 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2015 RehiveTech. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of RehiveTech nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _RTE_ATOMIC_ARM_H_
+#define _RTE_ATOMIC_ARM_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "generic/rte_atomic.h"
+
+/**
+ * General memory barrier.
+ *
+ * Guarantees that the LOAD and STORE operations generated before the
+ * barrier occur before the LOAD and STORE operations generated after.
+ */
+#define	rte_mb()  __sync_synchronize()
+
+/**
+ * Write memory barrier.
+ *
+ * Guarantees that the STORE operations generated before the barrier
+ * occur before the STORE operations generated after.
+ */
+#define	rte_wmb() do { asm volatile ("dmb st" : : : "memory"); } while (0)
+
+/**
+ * Read memory barrier.
+ *
+ * Guarantees that the LOAD operations generated before the barrier
+ * occur before the LOAD operations generated after.
+ */
+#define	rte_rmb() __sync_synchronize()
+
+/*------------------------- 16 bit atomic operations -------------------------*/
+
+#ifndef RTE_FORCE_INTRINSICS
+static inline int
+rte_atomic16_cmpset(volatile uint16_t *dst, uint16_t exp, uint16_t src)
+{
+	return __atomic_compare_exchange(dst, &exp, &src, 0, __ATOMIC_ACQUIRE,
+		__ATOMIC_ACQUIRE) ? 1 : 0;
+}
+
+static inline int rte_atomic16_test_and_set(rte_atomic16_t *v)
+{
+	return rte_atomic16_cmpset((volatile uint16_t *)&v->cnt, 0, 1);
+}
+
+static inline void
+rte_atomic16_inc(rte_atomic16_t *v)
+{
+	__atomic_add_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE);
+}
+
+static inline void
+rte_atomic16_dec(rte_atomic16_t *v)
+{
+	__atomic_sub_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE);
+}
+
+static inline int rte_atomic16_inc_and_test(rte_atomic16_t *v)
+{
+	return (__atomic_add_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE) == 0);
+}
+
+static inline int rte_atomic16_dec_and_test(rte_atomic16_t *v)
+{
+	return (__atomic_sub_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE) == 0);
+}
+
+/*------------------------- 32 bit atomic operations -------------------------*/
+
+static inline int
+rte_atomic32_cmpset(volatile uint32_t *dst, uint32_t exp, uint32_t src)
+{
+	return __atomic_compare_exchange(dst, &exp, &src, 0, __ATOMIC_ACQUIRE,
+		__ATOMIC_ACQUIRE) ? 1 : 0;
+}
+
+static inline int rte_atomic32_test_and_set(rte_atomic32_t *v)
+{
+	return rte_atomic32_cmpset((volatile uint32_t *)&v->cnt, 0, 1);
+}
+
+static inline void
+rte_atomic32_inc(rte_atomic32_t *v)
+{
+	__atomic_add_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE);
+}
+
+static inline void
+rte_atomic32_dec(rte_atomic32_t *v)
+{
+	__atomic_sub_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE);
+}
+
+static inline int rte_atomic32_inc_and_test(rte_atomic32_t *v)
+{
+	return (__atomic_add_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE) == 0);
+}
+
+static inline int rte_atomic32_dec_and_test(rte_atomic32_t *v)
+{
+	return (__atomic_sub_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE) == 0);
+}
+
+/*------------------------- 64 bit atomic operations -------------------------*/
+
+static inline int
+rte_atomic64_cmpset(volatile uint64_t *dst, uint64_t exp, uint64_t src)
+{
+	return __atomic_compare_exchange(dst, &exp, &src, 0, __ATOMIC_ACQUIRE,
+		__ATOMIC_ACQUIRE) ? 1 : 0;
+}
+
+static inline void
+rte_atomic64_init(rte_atomic64_t *v)
+{
+	int success = 0;
+	uint64_t tmp;
+
+	while (success == 0) {
+		tmp = v->cnt;
+		success = rte_atomic64_cmpset(
+				(volatile uint64_t *)&v->cnt, tmp, 0);
+	}
+}
+
+static inline int64_t
+rte_atomic64_read(rte_atomic64_t *v)
+{
+	int success = 0;
+	uint64_t tmp;
+
+	while (success == 0) {
+		tmp = v->cnt;
+		/* replace the value by itself */
+		success = rte_atomic64_cmpset(
+				(volatile uint64_t *) &v->cnt, tmp, tmp);
+	}
+	return tmp;
+}
+
+static inline void
+rte_atomic64_set(rte_atomic64_t *v, int64_t new_value)
+{
+	int success = 0;
+	uint64_t tmp;
+
+	while (success == 0) {
+		tmp = v->cnt;
+		success = rte_atomic64_cmpset(
+				(volatile uint64_t *)&v->cnt, tmp, new_value);
+	}
+}
+
+static inline void
+rte_atomic64_add(rte_atomic64_t *v, int64_t inc)
+{
+	__atomic_fetch_add(&v->cnt, inc, __ATOMIC_ACQUIRE);
+}
+
+static inline void
+rte_atomic64_sub(rte_atomic64_t *v, int64_t dec)
+{
+	__atomic_fetch_sub(&v->cnt, dec, __ATOMIC_ACQUIRE);
+}
+
+static inline void
+rte_atomic64_inc(rte_atomic64_t *v)
+{
+	__atomic_fetch_add(&v->cnt, 1, __ATOMIC_ACQUIRE);
+}
+
+static inline void
+rte_atomic64_dec(rte_atomic64_t *v)
+{
+	__atomic_fetch_sub(&v->cnt, 1, __ATOMIC_ACQUIRE);
+}
+
+static inline int64_t
+rte_atomic64_add_return(rte_atomic64_t *v, int64_t inc)
+{
+	return __atomic_add_fetch(&v->cnt, inc, __ATOMIC_ACQUIRE);
+}
+
+static inline int64_t
+rte_atomic64_sub_return(rte_atomic64_t *v, int64_t dec)
+{
+	return __atomic_sub_fetch(&v->cnt, dec, __ATOMIC_ACQUIRE);
+}
+
+static inline int rte_atomic64_inc_and_test(rte_atomic64_t *v)
+{
+	return (__atomic_add_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE) == 0);
+}
+
+static inline int rte_atomic64_dec_and_test(rte_atomic64_t *v)
+{
+	return (__atomic_sub_fetch(&v->cnt, 1, __ATOMIC_ACQUIRE) == 0);
+}
+
+static inline int rte_atomic64_test_and_set(rte_atomic64_t *v)
+{
+	return rte_atomic64_cmpset((volatile uint64_t *)&v->cnt, 0, 1);
+}
+
+/**
+ * Atomically set a 64-bit counter to 0.
+ *
+ * @param v
+ *   A pointer to the atomic counter.
+ */
+static inline void rte_atomic64_clear(rte_atomic64_t *v)
+{
+	rte_atomic64_set(v, 0);
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_ATOMIC_ARM_H_ */
-- 
2.6.1