xref: /freebsd/contrib/llvm-project/compiler-rt/lib/tsan/rtl/tsan_external.cpp (revision e6bfd18d21b225af6a0ed67ceeaf1293b7b9eba5)
1 //===-- tsan_external.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 ThreadSanitizer (TSan), a race detector.
10 //
11 //===----------------------------------------------------------------------===//
12 #include "tsan_rtl.h"
13 #include "sanitizer_common/sanitizer_ptrauth.h"
14 
15 #if !SANITIZER_GO
16 #  include "tsan_interceptors.h"
17 #endif
18 
19 namespace __tsan {
20 
21 #define CALLERPC ((uptr)__builtin_return_address(0))
22 
23 struct TagData {
24   const char *object_type;
25   const char *header;
26 };
27 
28 static TagData registered_tags[kExternalTagMax] = {
29   {},
30   {"Swift variable", "Swift access race"},
31 };
32 static atomic_uint32_t used_tags{kExternalTagFirstUserAvailable};
33 static TagData *GetTagData(uptr tag) {
34   // Invalid/corrupted tag?  Better return NULL and let the caller deal with it.
35   if (tag >= atomic_load(&used_tags, memory_order_relaxed)) return nullptr;
36   return &registered_tags[tag];
37 }
38 
39 const char *GetObjectTypeFromTag(uptr tag) {
40   TagData *tag_data = GetTagData(tag);
41   return tag_data ? tag_data->object_type : nullptr;
42 }
43 
44 const char *GetReportHeaderFromTag(uptr tag) {
45   TagData *tag_data = GetTagData(tag);
46   return tag_data ? tag_data->header : nullptr;
47 }
48 
49 void InsertShadowStackFrameForTag(ThreadState *thr, uptr tag) {
50   FuncEntry(thr, (uptr)&registered_tags[tag]);
51 }
52 
53 uptr TagFromShadowStackFrame(uptr pc) {
54   uptr tag_count = atomic_load(&used_tags, memory_order_relaxed);
55   void *pc_ptr = (void *)pc;
56   if (pc_ptr < GetTagData(0) || pc_ptr > GetTagData(tag_count - 1))
57     return 0;
58   return (TagData *)pc_ptr - GetTagData(0);
59 }
60 
61 #if !SANITIZER_GO
62 
63 void ExternalAccess(void *addr, uptr caller_pc, void *tag, AccessType typ) {
64   CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
65   ThreadState *thr = cur_thread();
66   if (caller_pc) FuncEntry(thr, caller_pc);
67   InsertShadowStackFrameForTag(thr, (uptr)tag);
68   bool in_ignored_lib;
69   if (!caller_pc || !libignore()->IsIgnored(caller_pc, &in_ignored_lib))
70     MemoryAccess(thr, CALLERPC, (uptr)addr, 1, typ);
71   FuncExit(thr);
72   if (caller_pc) FuncExit(thr);
73 }
74 
75 extern "C" {
76 SANITIZER_INTERFACE_ATTRIBUTE
77 void *__tsan_external_register_tag(const char *object_type) {
78   uptr new_tag = atomic_fetch_add(&used_tags, 1, memory_order_relaxed);
79   CHECK_LT(new_tag, kExternalTagMax);
80   GetTagData(new_tag)->object_type = internal_strdup(object_type);
81   char header[127] = {0};
82   internal_snprintf(header, sizeof(header), "race on %s", object_type);
83   GetTagData(new_tag)->header = internal_strdup(header);
84   return (void *)new_tag;
85 }
86 
87 SANITIZER_INTERFACE_ATTRIBUTE
88 void __tsan_external_register_header(void *tag, const char *header) {
89   CHECK_GE((uptr)tag, kExternalTagFirstUserAvailable);
90   CHECK_LT((uptr)tag, kExternalTagMax);
91   atomic_uintptr_t *header_ptr =
92       (atomic_uintptr_t *)&GetTagData((uptr)tag)->header;
93   header = internal_strdup(header);
94   char *old_header =
95       (char *)atomic_exchange(header_ptr, (uptr)header, memory_order_seq_cst);
96   Free(old_header);
97 }
98 
99 SANITIZER_INTERFACE_ATTRIBUTE
100 void __tsan_external_assign_tag(void *addr, void *tag) {
101   CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
102   Allocator *a = allocator();
103   MBlock *b = nullptr;
104   if (a->PointerIsMine((void *)addr)) {
105     void *block_begin = a->GetBlockBegin((void *)addr);
106     if (block_begin) b = ctx->metamap.GetBlock((uptr)block_begin);
107   }
108   if (b) {
109     b->tag = (uptr)tag;
110   }
111 }
112 
113 SANITIZER_INTERFACE_ATTRIBUTE
114 void __tsan_external_read(void *addr, void *caller_pc, void *tag) {
115   ExternalAccess(addr, STRIP_PAC_PC(caller_pc), tag, kAccessRead);
116 }
117 
118 SANITIZER_INTERFACE_ATTRIBUTE
119 void __tsan_external_write(void *addr, void *caller_pc, void *tag) {
120   ExternalAccess(addr, STRIP_PAC_PC(caller_pc), tag, kAccessWrite);
121 }
122 }  // extern "C"
123 
124 #endif  // !SANITIZER_GO
125 
126 }  // namespace __tsan
127