1//===-- hwasan_exceptions.cpp ---------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is a part of HWAddressSanitizer.
10//
11// HWAddressSanitizer runtime.
12//===----------------------------------------------------------------------===//
13
14#include "hwasan_poisoning.h"
15#include "sanitizer_common/sanitizer_common.h"
16
17#include <unwind.h>
18
19using namespace __hwasan;
20using namespace __sanitizer;
21
22typedef _Unwind_Reason_Code PersonalityFn(int version, _Unwind_Action actions,
23                                          uint64_t exception_class,
24                                          _Unwind_Exception* unwind_exception,
25                                          _Unwind_Context* context);
26
27// Pointers to the _Unwind_GetGR and _Unwind_GetCFA functions are passed in
28// instead of being called directly. This is to handle cases where the unwinder
29// is statically linked and the sanitizer runtime and the program are linked
30// against different unwinders. The _Unwind_Context data structure is opaque so
31// it may be incompatible between unwinders.
32typedef _Unwind_Word GetGRFn(_Unwind_Context* context, int index);
33typedef _Unwind_Word GetCFAFn(_Unwind_Context* context);
34
35extern "C" SANITIZER_INTERFACE_ATTRIBUTE _Unwind_Reason_Code
36__hwasan_personality_wrapper(int version, _Unwind_Action actions,
37                             uint64_t exception_class,
38                             _Unwind_Exception* unwind_exception,
39                             _Unwind_Context* context,
40                             PersonalityFn* real_personality, GetGRFn* get_gr,
41                             GetCFAFn* get_cfa) {
42  _Unwind_Reason_Code rc;
43  if (real_personality)
44    rc = real_personality(version, actions, exception_class, unwind_exception,
45                          context);
46  else
47    rc = _URC_CONTINUE_UNWIND;
48
49  // We only untag frames without a landing pad because landing pads are
50  // responsible for untagging the stack themselves if they resume.
51  //
52  // Here we assume that the frame record appears after any locals. This is not
53  // required by AAPCS but is a requirement for HWASAN instrumented functions.
54  if ((actions & _UA_CLEANUP_PHASE) && rc == _URC_CONTINUE_UNWIND) {
55#if defined(__x86_64__)
56    uptr fp = get_gr(context, 6); // rbp
57#elif defined(__aarch64__)
58    uptr fp = get_gr(context, 29); // x29
59#else
60#error Unsupported architecture
61#endif
62    uptr sp = get_cfa(context);
63    TagMemory(sp, fp - sp, 0);
64  }
65
66  return rc;
67}
68