sparc: Use atomic compiler builtins on sparc

This patch removes the arch-specific atomic instruction, relying on
compiler builtins.  The __sparc32_atomic_locks support is removed
and a configure check is added to check if compiler uses libatomic
to implement CAS.

It also removes the sparc specific sem_* and pthread_barrier_*
implementations.  It in turn allows buidling against a LEON3/LEON4
sparcv8 target, although it will still be incompatible with generic
sparcv9.

Checked on sparcv9-linux-gnu and sparc64-linux-gnu.  I also checked
with build against sparcv8-linux-gnu with -mcpu=leon3.

Tested-by: Andreas Larsson <andreas@gaisler.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/sysdeps/sparc/atomic-machine.h b/sysdeps/sparc/atomic-machine.h
new file mode 100644
index 0000000000..4453184c9c
--- /dev/null
+++ b/sysdeps/sparc/atomic-machine.h
@@ -0,0 +1,95 @@
+/* Atomic operations.  Sparc version.
+   Copyright (C) 2019 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 _ATOMIC_MACHINE_H
+#define _ATOMIC_MACHINE_H	1
+
+#include <stdint.h>
+
+typedef int8_t atomic8_t;
+typedef uint8_t uatomic8_t;
+typedef int_fast8_t atomic_fast8_t;
+typedef uint_fast8_t uatomic_fast8_t;
+
+typedef int16_t atomic16_t;
+typedef uint16_t uatomic16_t;
+typedef int_fast16_t atomic_fast16_t;
+typedef uint_fast16_t uatomic_fast16_t;
+
+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 int64_t atomic64_t;
+typedef uint64_t uatomic64_t;
+typedef int_fast64_t atomic_fast64_t;
+typedef uint_fast64_t uatomic_fast64_t;
+
+typedef intptr_t atomicptr_t;
+typedef uintptr_t uatomicptr_t;
+typedef intmax_t atomic_max_t;
+typedef uintmax_t uatomic_max_t;
+
+#ifdef __arch64__
+# define __HAVE_64B_ATOMICS          1
+#else
+# define __HAVE_64B_ATOMICS          0
+#endif
+#define USE_ATOMIC_COMPILER_BUILTINS 1
+
+/* XXX Is this actually correct?  */
+#define ATOMIC_EXCHANGE_USES_CAS     __HAVE_64B_ATOMICS
+
+/* Compare and exchange.
+   For all "bool" routines, we return FALSE if exchange succesful.  */
+
+#define __arch_compare_and_exchange_val_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)		      \
+  ({									      \
+    __typeof ((__typeof (*(mem))) *(mem)) __result;			      \
+    if (sizeof (*mem) == 4						      \
+        || (__HAVE_64B_ATOMICS && sizeof (*mem) == 8))			      \
+      __result = __arch_compare_and_exchange_val_int (mem, new, old,	      \
+							 __ATOMIC_ACQUIRE);   \
+    else								      \
+      abort ();								      \
+    __result;								      \
+  })
+
+#ifdef __sparc_v9__
+# define atomic_full_barrier() \
+  __asm __volatile ("membar #LoadLoad | #LoadStore"			      \
+		    " | #StoreLoad | #StoreStore" : : : "memory")
+# define atomic_read_barrier() \
+  __asm __volatile ("membar #LoadLoad | #LoadStore" : : : "memory")
+# define atomic_write_barrier() \
+  __asm __volatile ("membar #LoadStore | #StoreStore" : : : "memory")
+
+extern void __cpu_relax (void);
+# define atomic_spin_nop() __cpu_relax ()
+#endif
+
+#endif /* _ATOMIC_MACHINE_H  */