1 files changed, 107 insertions, 0 deletions
diff --git a/arch/hexagon/include/asm/futex.h b/arch/hexagon/include/asm/futex.h
new file mode 100644
index 000000000..9fb00a0ae
--- /dev/null
+++ b/arch/hexagon/include/asm/futex.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_HEXAGON_FUTEX_H
+#define _ASM_HEXAGON_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/errno.h>
+
+/* XXX TODO-- need to add sync barriers! */
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
+	__asm__ __volatile( \
+	"1: %0 = memw_locked(%3);\n" \
+	    /* For example: %1 = %4 */ \
+	    insn \
+	"2: memw_locked(%3,p2) = %1;\n" \
+	"   if (!p2) jump 1b;\n" \
+	"   %1 = #0;\n" \
+	"3:\n" \
+	".section .fixup,\"ax\"\n" \
+	"4: %1 = #%5;\n" \
+	"   jump ##3b\n" \
+	".previous\n" \
+	".section __ex_table,\"a\"\n" \
+	".long 1b,4b,2b,4b\n" \
+	".previous\n" \
+	: "=&r" (oldval), "=&r" (ret), "+m" (*uaddr) \
+	: "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
+	: "p2", "memory")
+
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+	int oldval = 0, ret;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("%1 = %4\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("%1 = add(%0,%4)\n", ret, oldval, uaddr,
+				  oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("%1 = or(%0,%4)\n", ret, oldval, uaddr,
+				  oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("%1 = not(%4); %1 = and(%0,%1)\n", ret,
+				  oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("%1 = xor(%0,%4)\n", ret, oldval, uaddr,
+				  oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
+			      u32 newval)
+{
+	int prev;
+	int ret;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	__asm__ __volatile__ (
+	"1: %1 = memw_locked(%3)\n"
+	"   {\n"
+	"      p2 = cmp.eq(%1,%4)\n"
+	"      if (!p2.new) jump:NT 3f\n"
+	"   }\n"
+	"2: memw_locked(%3,p2) = %5\n"
+	"   if (!p2) jump 1b\n"
+	"3:\n"
+	".section .fixup,\"ax\"\n"
+	"4: %0 = #%6\n"
+	"   jump ##3b\n"
+	".previous\n"
+	".section __ex_table,\"a\"\n"
+	".long 1b,4b,2b,4b\n"
+	".previous\n"
+	: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
+	: "r" (uaddr), "r" (oldval), "r" (newval), "i"(-EFAULT)
+	: "p2", "memory");
+
+	*uval = prev;
+	return ret;
+}
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_HEXAGON_FUTEX_H */