Move ring0 package.

This allows the package to serve as a general purpose ring0 support package, as
opposed to being bound to specific sentry platforms.

Updates #5039

PiperOrigin-RevId: 355220044

1 files changed, 41 insertions, 0 deletions

diff --git a/pkg/ring0/kernel_unsafe.go b/pkg/ring0/kernel_unsafe.go
new file mode 100644
index 000000000..16955ad91
--- /dev/null
+++ b/pkg/ring0/kernel_unsafe.go
@@ -0,0 +1,41 @@
+// 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.
+
+package ring0
+
+import (
+	"unsafe"
+)
+
+// eface mirrors runtime.eface.
+type eface struct {
+	typ  uintptr
+	data unsafe.Pointer
+}
+
+// kernelAddr returns the kernel virtual address for the given object.
+//
+//go:nosplit
+func kernelAddr(obj interface{}) uintptr {
+	e := (*eface)(unsafe.Pointer(&obj))
+	return KernelStartAddress | uintptr(e.data)
+}
+
+// kernelFunc returns the address of the given function.
+//
+//go:nosplit
+func kernelFunc(fn func()) uintptr {
+	fnptr := (**uintptr)(unsafe.Pointer(&fn))
+	return KernelStartAddress | **fnptr
+}