1 /*
2 * Copyright (C) 2023 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "berberis/runtime_primitives/runtime_library.h"
18
19 #include <csetjmp>
20
21 #include "berberis/base/checks.h"
22 #include "berberis/base/logging.h"
23 #include "berberis/base/tracing.h"
24 #include "berberis/guest_os_primitives/guest_thread.h"
25 #include "berberis/guest_state/guest_state_opaque.h"
26 #include "berberis/runtime/execute_guest.h"
27
28 namespace berberis {
29
ExecuteGuestCall(ThreadState * state)30 void ExecuteGuestCall(ThreadState* state) {
31 CHECK(state);
32 auto* thread = GetGuestThread(*state);
33 GuestCallExecution guest_call_execution{.parent = thread->guest_call_execution(),
34 .sp = GetStackRegister(GetCPUState(*state))};
35
36 // ATTENTION: don't save/restore signal mask, this is done by guest!
37 sigsetjmp(guest_call_execution.buf, 0);
38 // Set current execution for normal flow, or reset it after a longjmp.
39 thread->set_guest_call_execution(&guest_call_execution);
40
41 ExecuteGuest(state);
42
43 thread->set_guest_call_execution(guest_call_execution.parent);
44
45 if (guest_call_execution.sp == GetStackRegister(GetCPUState(*state))) {
46 return;
47 }
48
49 // Stack pointer may not be restored if guest executed a statically linked longjmp.
50 // Search parent executions for current sp.
51 for (auto* curr = thread->guest_call_execution(); curr; curr = curr->parent) {
52 // TODO(b/232598137): It'd be more reliable to also check (stop_pc ==
53 // insn_addr) for the matching execution, but currently stop_pc is always the
54 // same for all executions.
55 if (curr->sp == GetStackRegister(GetCPUState(*state))) {
56 TRACE("Detected statically linked longjmp");
57 siglongjmp(curr->buf, 1);
58 }
59 }
60
61 LOG_ALWAYS_FATAL("Guest call didn't restore sp: expected %p, actual %p",
62 ToHostAddr<void>(guest_call_execution.sp),
63 ToHostAddr<void>(GetStackRegister(GetCPUState(*state))));
64 }
65
66 } // namespace berberis
67