Copy files from ../librthread in preparation for moving functionality

from libpthread to libc.  No changes to the build yet, just making it
easier to review the substantive diffs.

ok beck@ kettenis@ tedu@

1 files changed, 49 insertions, 0 deletions

diff --git a/lib/libc/arch/aarch64/gen/_atomic_lock.c b/lib/libc/arch/aarch64/gen/_atomic_lock.c
new file mode 100644
index 00000000000..f4b0ad30508
--- /dev/null
+++ b/lib/libc/arch/aarch64/gen/_atomic_lock.c
@@ -0,0 +1,49 @@
+/*	$OpenBSD: _atomic_lock.c,v 1.1 2017/08/15 06:16:37 guenther Exp $	*/
+
+/*
+ * Copyright (c) 2004 Dale Rahn. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */ 
+
+/*
+ * Atomic lock for arm
+ */
+
+#include <sys/types.h>
+#include <machine/spinlock.h>
+
+int
+_atomic_lock(volatile _atomic_lock_t *lock)
+{
+	_atomic_lock_t old = 0;
+	uint32_t scratch = 0;
+
+	__asm__("1: ldaxr %w0, [%x1]       \n"
+		"   stlxr %w2, %w3, [%x1]  \n"
+		"   cmp %w2, #0            \n"
+		"   bne 1b                 \n"
+		"   dmb sy                 \n"
+		: "+r" (old), "+r" (lock), "+r" (scratch)
+		: "r" (_ATOMIC_LOCK_LOCKED));
+
+	return (old != _ATOMIC_LOCK_UNLOCKED);
+}