[dev.cc] runtime: fix lfstack for amd64 addresses in top half of addr space

While we are here, add the linux/power64 version.

LGTM=austin
R=austin
CC=aram, dvyukov, golang-codereviews
https://golang.org/cl/177750043

1 files changed, 4 insertions, 15 deletions

diff --git a/src/runtime/lfstack.go b/src/runtime/lfstack.go
index c5dc94f073..4a20fff9d8 100644
--- a/src/runtime/lfstack.go
+++ b/src/runtime/lfstack.go
@@ -9,23 +9,12 @@ package runtime
 
 import "unsafe"
 
-const (
-	// lfPtrBits and lfCountMask are defined in lfstack_*.go.
-	lfPtrMask = 1<<lfPtrBits - 1
-)
-
 func lfstackpush(head *uint64, node *lfnode) {
-	unode := uintptr(unsafe.Pointer(node))
-	if unode&^lfPtrMask != 0 {
-		print("p=", node, "\n")
-		gothrow("lfstackpush: invalid pointer")
-	}
-
 	node.pushcnt++
-	new := uint64(unode) | (uint64(node.pushcnt)&lfCountMask)<<lfPtrBits
+	new := lfstackPack(node, node.pushcnt)
 	for {
 		old := atomicload64(head)
-		node.next = (*lfnode)(unsafe.Pointer(uintptr(old & lfPtrMask)))
+		node.next, _ = lfstackUnpack(old)
 		if cas64(head, old, new) {
 			break
 		}
@@ -38,11 +27,11 @@ func lfstackpop(head *uint64) unsafe.Pointer {
 		if old == 0 {
 			return nil
 		}
-		node := (*lfnode)(unsafe.Pointer(uintptr(old & lfPtrMask)))
+		node, _ := lfstackUnpack(old)
 		node2 := (*lfnode)(atomicloadp(unsafe.Pointer(&node.next)))
 		new := uint64(0)
 		if node2 != nil {
-			new = uint64(uintptr(unsafe.Pointer(node2))) | uint64(node2.pushcnt&lfCountMask)<<lfPtrBits
+			new = lfstackPack(node2, node2.pushcnt)
 		}
 		if cas64(head, old, new) {
 			return unsafe.Pointer(node)