Index: lldb/source/Plugins/Process/OpenBSDKernel/RegisterContextOpenBSDKernel_arm64.cpp
--- lldb/source/Plugins/Process/OpenBSDKernel/RegisterContextOpenBSDKernel_arm64.cpp.orig
+++ lldb/source/Plugins/Process/OpenBSDKernel/RegisterContextOpenBSDKernel_arm64.cpp
@@ -0,0 +1,107 @@
+//===-- RegisterContextOpenBSDKernel_arm64.cpp ----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__OpenBSD__)
+#include <sys/types.h>
+#include <sys/time.h>
+#define _KERNEL
+#include <machine/cpu.h>
+#undef _KERNEL
+#include <machine/pcb.h>
+#include <frame.h>
+#endif
+
+#include "RegisterContextOpenBSDKernel_arm64.h"
+#include "Plugins/Process/Utility/lldb-arm64-register-enums.h"
+
+#include "lldb/Target/Process.h"
+#include "lldb/Target/Thread.h"
+#include "lldb/Utility/RegisterValue.h"
+#include "llvm/Support/Endian.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+RegisterContextOpenBSDKernel_arm64::RegisterContextOpenBSDKernel_arm64(
+    Thread &thread, std::unique_ptr<RegisterInfoPOSIX_arm64> register_info_up,
+    lldb::addr_t pcb_addr)
+    : RegisterContextPOSIX_arm64(thread, std::move(register_info_up)),
+      m_pcb_addr(pcb_addr) {}
+
+bool RegisterContextOpenBSDKernel_arm64::ReadGPR() { return true; }
+
+bool RegisterContextOpenBSDKernel_arm64::ReadFPR() { return true; }
+
+bool RegisterContextOpenBSDKernel_arm64::WriteGPR() {
+  assert(0);
+  return false;
+}
+
+bool RegisterContextOpenBSDKernel_arm64::WriteFPR() {
+  assert(0);
+  return false;
+}
+
+bool RegisterContextOpenBSDKernel_arm64::ReadRegister(
+    const RegisterInfo *reg_info, RegisterValue &value) {
+  if (m_pcb_addr == LLDB_INVALID_ADDRESS)
+    return false;
+
+#ifdef __aarch64__
+  Status error;
+  struct pcb pcb;
+  size_t rd = m_thread.GetProcess()->ReadMemory(m_pcb_addr, &pcb, sizeof(pcb),
+						error);
+  if (rd != sizeof(pcb))
+    return false;
+
+  /*
+    Usually pcb is written in `cpu_switchto` function. This function writes
+    registers as same as the structure of  `swichframe`  in the stack.
+    We read the frame if it is.
+   */
+  struct switchframe sf;
+  rd = m_thread.GetProcess()->ReadMemory(pcb.pcb_sp, &sf, sizeof(sf), error);
+  if (rd != sizeof(sf))
+    return false;
+
+  uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
+  switch (reg) {
+#define REG(x)					\
+    case gpr_##x##_arm64:			\
+      value = (u_int64_t)sf.sf_##x;		\
+      return true;
+
+    REG(x19);
+    REG(x20);
+    REG(x21);
+    REG(x22);
+    REG(x23);
+    REG(x24);
+    REG(x25);
+    REG(x26);
+    REG(x27);
+    REG(x28);
+  case gpr_fp_arm64:
+    value = (u_int64_t)sf.sf_x29;
+    return true;
+  case gpr_sp_arm64:
+    value = (u_int64_t)(pcb.pcb_sp + sizeof(sf));
+    return true;
+  case gpr_pc_arm64:
+    value = (u_int64_t)sf.sf_lr;
+    return true;
+  }
+#endif
+  return false;
+}
+
+bool RegisterContextOpenBSDKernel_arm64::WriteRegister(
+    const RegisterInfo *reg_info, const RegisterValue &value) {
+  return false;
+}
