[glibc] ARC: Atomics and Locking primitives

[glibc] ARC: Atomics and Locking primitives

[Vineet Gupta]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9679dd5ecdf46fc697b287ec5cba0c4dc9a7afa7

commit 9679dd5ecdf46fc697b287ec5cba0c4dc9a7afa7
Author: Vineet Gupta <vgupta@synopsys.com>
Date:   Tue Oct 23 14:36:39 2018 -0700

    ARC: Atomics and Locking primitives
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 sysdeps/arc/atomic-machine.h | 69 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/sysdeps/arc/atomic-machine.h b/sysdeps/arc/atomic-machine.h
new file mode 100644
index 0000000000..1c8638bb44
--- /dev/null
+++ b/sysdeps/arc/atomic-machine.h
@@ -0,0 +1,69 @@
+/* Low-level functions for atomic operations. ARC version.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _ARC_BITS_ATOMIC_H
+#define _ARC_BITS_ATOMIC_H 1
+
+#include <stdint.h>
+
+typedef int32_t atomic32_t;
+typedef uint32_t uatomic32_t;
+typedef int_fast32_t atomic_fast32_t;
+typedef uint_fast32_t uatomic_fast32_t;
+
+typedef intptr_t atomicptr_t;
+typedef uintptr_t uatomicptr_t;
+typedef intmax_t atomic_max_t;
+typedef uintmax_t uatomic_max_t;
+
+#define __HAVE_64B_ATOMICS 0
+#define USE_ATOMIC_COMPILER_BUILTINS 1
+
+/* ARC does have legacy atomic EX reg, [mem] instruction but the micro-arch
+   is not as optimal as LLOCK/SCOND specially for SMP.  */
+#define ATOMIC_EXCHANGE_USES_CAS 1
+
+#define __arch_compare_and_exchange_bool_8_acq(mem, newval, oldval)	\
+  (abort (), 0)
+#define __arch_compare_and_exchange_bool_16_acq(mem, newval, oldval)	\
+  (abort (), 0)
+#define __arch_compare_and_exchange_bool_64_acq(mem, newval, oldval)	\
+  (abort (), 0)
+
+#define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model)	\
+  (abort (), (__typeof (*mem)) 0)
+#define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model)	\
+  (abort (), (__typeof (*mem)) 0)
+#define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model)	\
+  (abort (), (__typeof (*mem)) 0)
+
+#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 atomic_compare_and_exchange_val_acq(mem, new, old)		\
+  __atomic_val_bysize (__arch_compare_and_exchange_val, int,		\
+		       mem, new, old, __ATOMIC_ACQUIRE)
+
+#define atomic_full_barrier()  ({ asm volatile ("dmb 3":::"memory"); })
+
+#endif /* _ARC_BITS_ATOMIC_H */