6944589 need pause API

PSARC/2010/293 smt_pause

1 files changed, 55 insertions, 0 deletions

diff --git a/usr/src/lib/libc/sparcv9/gen/smt_pause.s b/usr/src/lib/libc/sparcv9/gen/smt_pause.s
new file mode 100644
index 0000000000..dadbb0c569
--- /dev/null
+++ b/usr/src/lib/libc/sparcv9/gen/smt_pause.s
@@ -0,0 +1,55 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+
+	.file	"smt_pause.s"
+
+#include <sys/asm_linkage.h>
+#include <../assym.h>
+
+/*
+ * void smt_pause(void)
+ *
+ * Do nothing efficiently.
+ */
+
+#ifdef lint
+void
+smt_pause(void)
+{
+}
+#else
+#define	BANKS	(4 * 64)
+	ENTRY(smt_pause)
+	save %sp, -SA(MINFRAME+BANKS), %sp
+	ld      [%g7 + UL_LWPID], %i3   ! curthread->ul_lwpid
+	add	%fp, STACK_BIAS-BANKS, %i0
+	and     %i3, 0x3, %i2           ! save last 2 bits
+	sllx    %i2, 0x6, %i1           ! pick a slot
+	add     %i1, %i0, %o0
+	casx    [%o0], %g0, %g0
+	casx    [%o0], %g0, %g0
+	ret
+	restore
+	SET_SIZE(smt_pause)
+#endif