1 files changed, 55 insertions, 0 deletions
diff --git a/arch/tile/kernel/futex_64.S b/arch/tile/kernel/futex_64.S
new file mode 100644
index 000000000000..f465d1eda20f
--- /dev/null
+++ b/arch/tile/kernel/futex_64.S
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program 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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * Atomically access user memory, but use MMU to avoid propagating
+ * kernel exceptions.
+ */
+
+#include <linux/linkage.h>
+#include <asm/errno.h>
+#include <asm/futex.h>
+#include <asm/page.h>
+#include <asm/processor.h>
+
+/*
+ * Provide a set of atomic memory operations supporting <asm/futex.h>.
+ *
+ * r0: user address to manipulate
+ * r1: new value to write, or for cmpxchg, old value to compare against
+ * r2: (cmpxchg only) new value to write
+ *
+ * Return __get_user struct, r0 with value, r1 with error.
+ */
+#define FUTEX_OP(name, ...) \
+STD_ENTRY(futex_##name)			\
+	__VA_ARGS__;			\
+	{				\
+	 move   r1, zero;		\
+	 jrp    lr			\
+	};				\
+	STD_ENDPROC(futex_##name);	\
+	.pushsection __ex_table,"a";	\
+	.quad 1b, get_user_fault;	\
+	.popsection
+
+	.pushsection .fixup,"ax"
+get_user_fault:
+	{ movei r1, -EFAULT; jrp lr }
+	ENDPROC(get_user_fault)
+	.popsection
+
+FUTEX_OP(cmpxchg, mtspr CMPEXCH_VALUE, r1; 1: cmpexch4 r0, r0, r2)
+FUTEX_OP(set, 1: exch4 r0, r0, r1)
+FUTEX_OP(add, 1: fetchadd4 r0, r0, r1)
+FUTEX_OP(or, 1: fetchor4 r0, r0, r1)
+FUTEX_OP(andn, nor r1, r1, zero; 1: fetchand4 r0, r0, r1)