Enable clone syscall support on arm64.

sys_clone has many flavors in Linux, and amd64 chose
a different one from x86(different arguments order).
Ref kernel/fork.c for more info.

Signed-off-by: Haibo Xu <haibo.xu@arm.com>
Change-Id: I6c8cbc685f4a6e786b171715ab68292fc95cbf48
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/gvisor/pull/1545 from xiaobo55x:clone 156bd2dfbc63ef5291627b0578ddea77997393b2
PiperOrigin-RevId: 290093953

1 files changed, 35 insertions, 0 deletions

diff --git a/pkg/sentry/syscalls/linux/sys_clone_arm64.go b/pkg/sentry/syscalls/linux/sys_clone_arm64.go
new file mode 100644
index 000000000..cf68a8949
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/sys_clone_arm64.go
@@ -0,0 +1,35 @@
+// Copyright 2020 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.
+
+// +build arm64
+
+package linux
+
+import (
+	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+)
+
+// Clone implements linux syscall clone(2).
+// sys_clone has so many flavors, and we implement the default one in linux 3.11
+// arm64(kernel/fork.c with CONFIG_CLONE_BACKWARDS defined in the config file):
+//    sys_clone(clone_flags, newsp, parent_tidptr, tls_val, child_tidptr)
+func Clone(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	flags := int(args[0].Int())
+	stack := args[1].Pointer()
+	parentTID := args[2].Pointer()
+	tls := args[3].Pointer()
+	childTID := args[4].Pointer()
+	return clone(t, flags, stack, parentTID, childTID, tls)
+}