sh: Fix up futex implementation.

SH is able to support a complete futex implementation on UP by way
of gUSA. However, IRQ toggling must be done for the old CPUs that
don't have movli.l/movco.l (LL/SC) instructions. Provide a default
implementation that does this, so it's possible to optimize for
newer CPUs.

Follows the same scheme as the current asm-sh/atomic-*.h headers.

Signed-off-by: Kaz Kojima <kkojima@rr.iij4u.or.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/asm-sh/futex-irq.h

@@ -0,0 +1,111 @@
+#ifndef __ASM_SH_FUTEX_IRQ_H
+#define __ASM_SH_FUTEX_IRQ_H
+
+#include <asm/system.h>
+
+static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr,
+					   int *oldval)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+
+	ret = get_user(*oldval, uaddr);
+	if (!ret)
+		ret = put_user(oparg, uaddr);
+
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr,
+					   int *oldval)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+
+	ret = get_user(*oldval, uaddr);
+	if (!ret)
+		ret = put_user(*oldval + oparg, uaddr);
+
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr,
+					  int *oldval)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+
+	ret = get_user(*oldval, uaddr);
+	if (!ret)
+		ret = put_user(*oldval | oparg, uaddr);
+
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr,
+					   int *oldval)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+
+	ret = get_user(*oldval, uaddr);
+	if (!ret)
+		ret = put_user(*oldval & oparg, uaddr);
+
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr,
+					   int *oldval)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+
+	ret = get_user(*oldval, uaddr);
+	if (!ret)
+		ret = put_user(*oldval ^ oparg, uaddr);
+
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static inline int atomic_futex_op_cmpxchg_inatomic(int __user *uaddr,
+						   int oldval, int newval)
+{
+	unsigned long flags;
+	int ret, prev = 0;
+
+	local_irq_save(flags);
+
+	ret = get_user(prev, uaddr);
+	if (!ret && oldval == prev)
+		ret = put_user(newval, uaddr);
+
+	local_irq_restore(flags);
+
+	if (ret)
+		return ret;
+
+	return prev;
+}
+
+#endif /* __ASM_SH_FUTEX_IRQ_H */