From 2db866c45f44f302d666172aceaad92901db14af Mon Sep 17 00:00:00 2001
From: Haibo Xu <haibo.xu@arm.com>
Date: Thu, 22 Aug 2019 09:01:47 +0000
Subject: [PATCH] Enable pkg/sleep support on arm64.

Signed-off-by: Haibo Xu <haibo.xu@arm.com>
Change-Id: I9071e698c1f222e0fdf3b567ec4cbd97f0a8dde9
---
 pkg/sleep/BUILD           |  1 +
 pkg/sleep/commit_arm64.s  | 38 ++++++++++++++++++++++++++++++++++++++
 pkg/sleep/commit_asm.go   |  2 +-
 pkg/sleep/commit_noasm.go |  2 +-
 4 files changed, 41 insertions(+), 2 deletions(-)
 create mode 100644 pkg/sleep/commit_arm64.s

diff --git a/pkg/sleep/BUILD b/pkg/sleep/BUILD
index bdca80d37..a23c86fb1 100644
--- a/pkg/sleep/BUILD
+++ b/pkg/sleep/BUILD
@@ -7,6 +7,7 @@ go_library(
     name = "sleep",
     srcs = [
         "commit_amd64.s",
+        "commit_arm64.s",
         "commit_asm.go",
         "commit_noasm.go",
         "sleep_unsafe.go",
diff --git a/pkg/sleep/commit_arm64.s b/pkg/sleep/commit_arm64.s
new file mode 100644
index 000000000..d0ef15b20
--- /dev/null
+++ b/pkg/sleep/commit_arm64.s
@@ -0,0 +1,38 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "textflag.h"
+
+#define preparingG 1
+
+// See commit_noasm.go for a description of commitSleep.
+//
+// func commitSleep(g uintptr, waitingG *uintptr) bool
+TEXT ·commitSleep(SB),NOSPLIT,$0-24
+	MOVD waitingG+8(FP), R0
+	MOVD $preparingG, R1
+	MOVD G+0(FP), R2
+
+	// Store the G in waitingG if it's still preparingG. If it's anything
+	// else it means a waker has aborted the sleep.
+again:
+        LDAXR   (R0), R3
+        CMP     R1, R3
+        BNE     ok
+        STLXR   R2, (R0), R3
+        CBNZ    R3, again
+ok:
+        CSET    EQ, R0
+        MOVB    R0, ret+16(FP)
+        RET
diff --git a/pkg/sleep/commit_asm.go b/pkg/sleep/commit_asm.go
index 35e2cc337..75728a97d 100644
--- a/pkg/sleep/commit_asm.go
+++ b/pkg/sleep/commit_asm.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build amd64
+// +build amd64 arm64
 
 package sleep
 
diff --git a/pkg/sleep/commit_noasm.go b/pkg/sleep/commit_noasm.go
index 686b1da3d..3af447fb9 100644
--- a/pkg/sleep/commit_noasm.go
+++ b/pkg/sleep/commit_noasm.go
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 // +build !race
-// +build !amd64
+// +build !amd64,!arm64
 
 package sleep