[PATCH 2/5] sysdeps/generic/atomic.h: Add a generic atomic header

[Will Newton <will dot newton at linaro dot org>]

Add a new header that uses modern GCC instrinsics for implementing
the atomic_* and catomic_* functions in a relatively efficient manner.
This code is based on the existing ARM and AArch64 implementations.

ChangeLog:

2014-10-15  Will Newton  <will.newton@linaro.org>

	* sysdeps/generic/atomic.h: New file.
---
 sysdeps/generic/atomic.h | 240 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 240 insertions(+)
 create mode 100644 sysdeps/generic/atomic.h

diff --git a/sysdeps/generic/atomic.h b/sysdeps/generic/atomic.h
new file mode 100644
index 0000000..dd1854e
--- /dev/null
+++ b/sysdeps/generic/atomic.h
@@ -0,0 +1,240 @@
+/* Atomic operations.  Generic GCC intrinsic version.
+   Copyright (C) 2002-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+void __atomic_link_error (void);
+
+/* Barrier macro. */
+#ifndef atomic_full_barrier
+# define atomic_full_barrier() __sync_synchronize()
+#endif
+
+/* Compare and exchange.
+   For all "bool" routines, we return FALSE if exchange successful.  */
+
+#define __arch_compare_and_exchange_bool_8_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_16_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_32_int(mem, newval, oldval, model) \
+  ({									\
+    typeof (*mem) __oldval = (oldval);					\
+    !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0,	\
+				  model, __ATOMIC_RELAXED);		\
+  })
+
+#if __ARCH_ATOMIC_64_SUPPORTED
+# define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
+  ({									\
+    typeof (*mem) __oldval = (oldval);					\
+    !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0,	\
+				  model, __ATOMIC_RELAXED);		\
+  })
+#else
+# define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
+  ({ __atomic_link_error (); 0; })
+#endif
+
+#define __arch_compare_and_exchange_val_8_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_16_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_32_int(mem, newval, oldval, model) \
+  ({									\
+    typeof (*mem) __oldval = (oldval);					\
+    __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0,	\
+				 model, __ATOMIC_RELAXED);		\
+    __oldval;								\
+  })
+
+#if __ARCH_ATOMIC_64_SUPPORTED
+# define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
+  ({									\
+    typeof (*mem) __oldval = (oldval);					\
+    __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0,	\
+				 model, __ATOMIC_RELAXED);		\
+    __oldval;								\
+  })
+#else
+# define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
+  ({ __atomic_link_error (); (__typeof (*(mem)))0; })
+#endif
+
+
+/* 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)
+
+
+/* Atomic exchange (without compare).  */
+
+#define __arch_exchange_8_int(mem, newval, model)	\
+  __atomic_exchange_n (mem, newval, model)
+
+#define __arch_exchange_16_int(mem, newval, model)	\
+  __atomic_exchange_n (mem, newval, model)
+
+#define __arch_exchange_32_int(mem, newval, model)	\
+  __atomic_exchange_n (mem, newval, model)
+
+#if __ARCH_ATOMIC_64_SUPPORTED
+# define __arch_exchange_64_int(mem, newval, model)	\
+  __atomic_exchange_n (mem, newval, model)
+#else
+# define __arch_exchange_64_int(mem, newval, model)	\
+  ({ __atomic_link_error (); (__typeof (*(mem)))0; })
+#endif
+
+#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)
+
+
+/* Atomically add value and return the previous (unincremented) value.  */
+
+#define __arch_exchange_and_add_8_int(mem, value, model)	\
+  __atomic_fetch_add (mem, value, model)
+
+#define __arch_exchange_and_add_16_int(mem, value, model)	\
+  __atomic_fetch_add (mem, value, model)
+
+#define __arch_exchange_and_add_32_int(mem, value, model)	\
+  __atomic_fetch_add (mem, value, model)
+
+#if __ARCH_ATOMIC_64_SUPPORTED
+# define __arch_exchange_and_add_64_int(mem, value, model)	\
+  __atomic_fetch_add (mem, value, model)
+#else
+# define __arch_exchange_and_add_64_int(mem, value, model)	\
+  ({ __atomic_link_error (); (__typeof (*(mem)))0; })
+#endif
+
+#define atomic_exchange_and_add_acq(mem, value)				\
+  __atomic_val_bysize (__arch_exchange_and_add, int, mem, value,	\
+		       __ATOMIC_ACQUIRE)
+
+#define atomic_exchange_and_add_rel(mem, value)				\
+  __atomic_val_bysize (__arch_exchange_and_add, int, mem, value,	\
+		       __ATOMIC_RELEASE)
+
+#define atomic_exchange_and_add_relaxed(mem, value)			\
+  __atomic_val_bysize (__arch_exchange_and_add, int, mem, value,	\
+		       __ATOMIC_RELAXED)
+
+#define catomic_exchange_and_add atomic_exchange_and_add_acq
+
+/* Atomically bitwise and value and return the previous value.  */
+
+#define __arch_exchange_and_and_8_int(mem, value, model)	\
+  __atomic_fetch_and (mem, value, model)
+
+#define __arch_exchange_and_and_16_int(mem, value, model)	\
+  __atomic_fetch_and (mem, value, model)
+
+#define __arch_exchange_and_and_32_int(mem, value, model)	\
+  __atomic_fetch_and (mem, value, model)
+
+#if __ARCH_ATOMIC_64_SUPPORTED
+# define __arch_exchange_and_and_64_int(mem, value, model)	\
+  __atomic_fetch_and (mem, value, model)
+#else
+# define __arch_exchange_and_and_64_int(mem, value, model)	\
+  ({ __atomic_link_error (); (__typeof (*(mem)))0; })
+#endif
+
+#define atomic_and(mem, value)						\
+  __atomic_val_bysize (__arch_exchange_and_and, int, mem, value,	\
+		       __ATOMIC_ACQUIRE)
+
+#define atomic_and_relaxed(mem, value)					\
+  __atomic_val_bysize (__arch_exchange_and_and, int, mem, value,	\
+		       __ATOMIC_RELAXED)
+
+#define atomic_and_val atomic_and
+
+#define catomic_and atomic_and
+
+/* Atomically bitwise or value and return the previous value.  */
+
+#define __arch_exchange_and_or_8_int(mem, value, model)	\
+  __atomic_fetch_or (mem, value, model)
+
+#define __arch_exchange_and_or_16_int(mem, value, model)	\
+  __atomic_fetch_or (mem, value, model)
+
+#define __arch_exchange_and_or_32_int(mem, value, model)	\
+  __atomic_fetch_or (mem, value, model)
+
+#if __ARCH_ATOMIC_64_SUPPORTED
+# define __arch_exchange_and_or_64_int(mem, value, model)	\
+  __atomic_fetch_or (mem, value, model)
+#else
+# define __arch_exchange_and_or_64_int(mem, value, model)	\
+  ({ __atomic_link_error (); (__typeof (*(mem)))0; })
+#endif
+
+#define atomic_or(mem, value)					\
+  __atomic_val_bysize (__arch_exchange_and_or, int, mem, value,	\
+		       __ATOMIC_ACQUIRE)
+
+#define atomic_or_relaxed(mem, value)				\
+  __atomic_val_bysize (__arch_exchange_and_or, int, mem, value,	\
+		       __ATOMIC_RELAXED)
+
+#define atomic_or_val atomic_or
+
+#define catomic_or atomic_or
-- 
1.9.3