1 files changed, 53 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_tls.go b/pkg/sentry/syscalls/linux/sys_tls.go
new file mode 100644
index 000000000..1e8312e00
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/sys_tls.go
@@ -0,0 +1,53 @@
+// Copyright 2018 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 amd64
+
+package linux
+
+import (
+	"syscall"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+)
+
+// ArchPrctl implements linux syscall arch_prctl(2).
+// It sets architecture-specific process or thread state for t.
+func ArchPrctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	switch args[0].Int() {
+	case linux.ARCH_GET_FS:
+		addr := args[1].Pointer()
+		fsbase := t.Arch().TLS()
+		_, err := t.CopyOut(addr, uint64(fsbase))
+		if err != nil {
+			return 0, nil, err
+		}
+
+	case linux.ARCH_SET_FS:
+		fsbase := args[1].Uint64()
+		if !t.Arch().SetTLS(uintptr(fsbase)) {
+			return 0, nil, syscall.EPERM
+		}
+
+	case linux.ARCH_GET_GS, linux.ARCH_SET_GS:
+		t.Kernel().EmitUnimplementedEvent(t)
+		fallthrough
+	default:
+		return 0, nil, syscall.EINVAL
+	}
+
+	return 0, nil, nil
+}