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>

2 files changed, 186 insertions, 4 deletions

diff --git a/include/asm-sh/futex-irq.h b/include/asm-sh/futex-irq.h
new file mode 100644
index 000000000000..a9f16a7f9aea
--- /dev/null
+++ b/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 */
diff --git a/include/asm-sh/futex.h b/include/asm-sh/futex.h
index 6a332a9f099c..74ed3681d33c 100644
--- a/include/asm-sh/futex.h
+++ b/include/asm-sh/futex.h
@@ -1,6 +1,77 @@
-#ifndef _ASM_FUTEX_H
-#define _ASM_FUTEX_H
+#ifndef __ASM_SH_FUTEX_H
+#define __ASM_SH_FUTEX_H
 
-#include <asm-generic/futex.h>
+#ifdef __KERNEL__
 
-#endif
+#include <linux/futex.h>
+#include <asm/errno.h>
+#include <asm/uaccess.h>
+
+/* XXX: UP variants, fix for SH-4A and SMP.. */
+#include <asm/futex-irq.h>
+
+static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
+{
+	int op = (encoded_op >> 28) & 7;
+	int cmp = (encoded_op >> 24) & 15;
+	int oparg = (encoded_op << 8) >> 20;
+	int cmparg = (encoded_op << 20) >> 20;
+	int oldval = 0, ret;
+
+	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+		oparg = 1 << oparg;
+
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+		return -EFAULT;
+
+	pagefault_disable();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_ADD:
+		ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_OR:
+		ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_ANDN:
+		ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);
+		break;
+	case FUTEX_OP_XOR:
+		ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);
+		break;
+	default:
+		ret = -ENOSYS;
+		break;
+	}
+
+	pagefault_enable();
+
+	if (!ret) {
+		switch (cmp) {
+		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
+		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
+		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
+		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
+		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
+		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
+		default: ret = -ENOSYS;
+		}
+	}
+
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
+{
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+		return -EFAULT;
+
+	return atomic_futex_op_cmpxchg_inatomic(uaddr, oldval, newval);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __ASM_SH_FUTEX_H */