1 files changed, 127 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/futex.h b/arch/xtensa/include/asm/futex.h
new file mode 100644
index 000000000..5bfbc1c40
--- /dev/null
+++ b/arch/xtensa/include/asm/futex.h
@@ -0,0 +1,127 @@
+/*
+ * Atomic futex routines
+ *
+ * Based on the PowerPC implementataion
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Copyright (C) 2013 TangoTec Ltd.
+ *
+ * Baruch Siach <baruch@tkos.co.il>
+ */
+
+#ifndef _ASM_XTENSA_FUTEX_H
+#define _ASM_XTENSA_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <linux/errno.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
+	__asm__ __volatile(				\
+	"1:	l32i	%0, %2, 0\n"			\
+		insn "\n"				\
+	"	wsr	%0, scompare1\n"		\
+	"2:	s32c1i	%1, %2, 0\n"			\
+	"	bne	%1, %0, 1b\n"			\
+	"	movi	%1, 0\n"			\
+	"3:\n"						\
+	"	.section .fixup,\"ax\"\n"		\
+	"	.align 4\n"				\
+	"4:	.long	3b\n"				\
+	"5:	l32r	%0, 4b\n"			\
+	"	movi	%1, %3\n"			\
+	"	jx	%0\n"				\
+	"	.previous\n"				\
+	"	.section __ex_table,\"a\"\n"		\
+	"	.long 1b,5b,2b,5b\n"			\
+	"	.previous\n"				\
+	: "=&r" (oldval), "=&r" (ret)			\
+	: "r" (uaddr), "I" (-EFAULT), "r" (oparg)	\
+	: "memory")
+
+static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
+		u32 __user *uaddr)
+{
+	int oldval = 0, ret;
+
+#if !XCHAL_HAVE_S32C1I
+	return -ENOSYS;
+#endif
+
+	pagefault_disable();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr,
+				oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr,
+				oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr,
+				~oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr,
+				oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	pagefault_enable();
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+			      u32 oldval, u32 newval)
+{
+	int ret = 0;
+
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+		return -EFAULT;
+
+#if !XCHAL_HAVE_S32C1I
+	return -ENOSYS;
+#endif
+
+	__asm__ __volatile__ (
+	"	# futex_atomic_cmpxchg_inatomic\n"
+	"	wsr	%5, scompare1\n"
+	"1:	s32c1i	%1, %4, 0\n"
+	"	s32i	%1, %6, 0\n"
+	"2:\n"
+	"	.section .fixup,\"ax\"\n"
+	"	.align 4\n"
+	"3:	.long	2b\n"
+	"4:	l32r	%1, 3b\n"
+	"	movi	%0, %7\n"
+	"	jx	%1\n"
+	"	.previous\n"
+	"	.section __ex_table,\"a\"\n"
+	"	.long 1b,4b\n"
+	"	.previous\n"
+	: "+r" (ret), "+r" (newval), "+m" (*uaddr), "+m" (*uval)
+	: "r" (uaddr), "r" (oldval), "r" (uval), "I" (-EFAULT)
+	: "memory");
+
+	return ret;
+}
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_XTENSA_FUTEX_H */