diff --git a/src/runtime/arch1_power64.go b/src/runtime/arch1_power64.go
new file mode 100644
index 00000000000..01e2b70f952
--- /dev/null
+++ b/src/runtime/arch1_power64.go
@@ -0,0 +1,15 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+const (
+	thechar           = '9'
+	_BigEndian        = 1
+	_CacheLineSize    = 64
+	_RuntimeGogoBytes = 64
+	_PhysPageSize     = 65536
+	_PCQuantum        = 4
+	_Int64Align       = 8
+)
diff --git a/src/runtime/arch1_power64le.go b/src/runtime/arch1_power64le.go
new file mode 100644
index 00000000000..6580732a371
--- /dev/null
+++ b/src/runtime/arch1_power64le.go
@@ -0,0 +1,15 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+const (
+	thechar           = '9'
+	_BigEndian        = 0
+	_CacheLineSize    = 64
+	_RuntimeGogoBytes = 64
+	_PhysPageSize     = 65536
+	_PCQuantum        = 4
+	_Int64Align       = 8
+)
diff --git a/src/runtime/arch_power64.h b/src/runtime/arch_power64.h
deleted file mode 100644
index 7cfb9da2fcd..00000000000
--- a/src/runtime/arch_power64.h
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-enum {
-	thechar = '9',
-	BigEndian = 1,
-	CacheLineSize = 64,
-	RuntimeGogoBytes = 64,
-	PhysPageSize = 65536,
-	PCQuantum = 4,
-	Int64Align = 8
-};
-
diff --git a/src/runtime/arch_power64le.h b/src/runtime/arch_power64le.h
deleted file mode 100644
index 684ac9953ba..00000000000
--- a/src/runtime/arch_power64le.h
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-enum {
-	thechar = '9',
-	BigEndian = 0,
-	CacheLineSize = 64,
-	RuntimeGogoBytes = 64,
-	PhysPageSize = 65536,
-	PCQuantum = 4,
-	Int64Align = 8
-};
-
diff --git a/src/runtime/atomic_power64x.go b/src/runtime/atomic_power64x.go
new file mode 100644
index 00000000000..a0dcf514b50
--- /dev/null
+++ b/src/runtime/atomic_power64x.go
@@ -0,0 +1,69 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build power64 power64le
+
+package runtime
+
+import "unsafe"
+
+//go:noescape
+func xadd(ptr *uint32, delta int32) uint32
+
+//go:noescape
+func xadd64(ptr *uint64, delta int64) uint64
+
+//go:noescape
+func xchg(ptr *uint32, new uint32) uint32
+
+//go:noescape
+func xchg64(ptr *uint64, new uint64) uint64
+
+// xchgp cannot have a go:noescape annotation, because
+// while ptr does not escape, new does. If new is marked as
+// not escaping, the compiler will make incorrect escape analysis
+// decisions about the value being xchg'ed.
+// Instead, make xchgp a wrapper around the actual atomic.
+// When calling the wrapper we mark ptr as noescape explicitly.
+
+//go:nosplit
+func xchgp(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer {
+	return xchgp1(noescape(ptr), new)
+}
+
+func xchgp1(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer
+
+//go:noescape
+func xchguintptr(ptr *uintptr, new uintptr) uintptr
+
+//go:noescape
+func atomicload(ptr *uint32) uint32
+
+//go:noescape
+func atomicload64(ptr *uint64) uint64
+
+//go:noescape
+func atomicloadp(ptr unsafe.Pointer) unsafe.Pointer
+
+//go:noescape
+func atomicor8(ptr *uint8, val uint8)
+
+//go:noescape
+func cas64(ptr *uint64, old, new uint64) bool
+
+//go:noescape
+func atomicstore(ptr *uint32, val uint32)
+
+//go:noescape
+func atomicstore64(ptr *uint64, val uint64)
+
+// atomicstorep cannot have a go:noescape annotation.
+// See comment above for xchgp.
+
+//go:nosplit
+func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) {
+	atomicstorep1(noescape(ptr), new)
+}
+
+func atomicstorep1(ptr unsafe.Pointer, val unsafe.Pointer)
diff --git a/src/runtime/sys_power64x.c b/src/runtime/sys_power64x.c
deleted file mode 100644
index 79d976255f5..00000000000
--- a/src/runtime/sys_power64x.c
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build power64 power64le
-
-#include "runtime.h"
-
-// adjust Gobuf as if it executed a call to fn with context ctxt
-// and then did an immediate Gosave.
-void
-runtime·gostartcall(Gobuf *gobuf, void (*fn)(void), void *ctxt)
-{
-	if(gobuf->lr != 0)
-		runtime·throw("invalid use of gostartcall");
-	gobuf->lr = gobuf->pc;
-	gobuf->pc = (uintptr)fn;
-	gobuf->ctxt = ctxt;
-}
-
-// Called to rewind context saved during morestack back to beginning of function.
-// To help us, the linker emits a jmp back to the beginning right after the
-// call to morestack. We just have to decode and apply that jump.
-void
-runtime·rewindmorestack(Gobuf *gobuf)
-{
-	uint32 inst;
-
-	inst = *(uint32*)gobuf->pc;
-	if((gobuf->pc&3) == 0 && (inst>>24) == 0x4b && (inst&3) == 0) {
-		//runtime·printf("runtime: rewind pc=%p to pc=%p\n", gobuf->pc, gobuf->pc + ((int32)(inst<<8)>>8));
-		gobuf->pc += (int32)(inst<<8)>>8;
-		return;
-	}
-	runtime·printf("runtime: pc=%p %x\n", gobuf->pc, inst);
-	runtime·throw("runtime: misuse of rewindmorestack");
-}
-
diff --git a/src/runtime/sys_power64x.go b/src/runtime/sys_power64x.go
new file mode 100644
index 00000000000..f32d1a44f15
--- /dev/null
+++ b/src/runtime/sys_power64x.go
@@ -0,0 +1,37 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build power64 power64le
+
+package runtime
+
+import "unsafe"
+
+// adjust Gobuf as if it executed a call to fn with context ctxt
+// and then did an immediate Gosave.
+func gostartcall(buf *gobuf, fn, ctxt unsafe.Pointer) {
+	if buf.lr != 0 {
+		gothrow("invalid use of gostartcall")
+	}
+	buf.lr = buf.pc
+	buf.pc = uintptr(fn)
+	buf.ctxt = ctxt
+}
+
+// Called to rewind context saved during morestack back to beginning of function.
+// To help us, the linker emits a jmp back to the beginning right after the
+// call to morestack. We just have to decode and apply that jump.
+func rewindmorestack(buf *gobuf) {
+	var inst uint32
+	if buf.pc&3 == 0 && buf.pc != 0 {
+		inst = *(*uint32)(unsafe.Pointer(buf.pc))
+		if inst>>24 == 0x4b && inst&3 == 0 {
+			//print("runtime: rewind pc=", hex(buf.pc), " to pc=", hex(uintptr(buf.pc + int32(inst<<8)>>8)), "\n");
+			buf.pc += uintptr(int32(inst<<8) >> 8)
+			return
+		}
+	}
+	print("runtime: pc=", hex(buf.pc), " ", hex(inst), "\n")
+	gothrow("runtime: misuse of rewindmorestack")
+}