1 /*
2 * Copyright (C) 2015 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 "OfflineUnwinder.h"
18
19 #include <sys/mman.h>
20
21 #include <unordered_map>
22
23 #include <android-base/logging.h>
24 #include <unwindstack/MachineArm.h>
25 #include <unwindstack/MachineArm64.h>
26 #include <unwindstack/MachineX86.h>
27 #include <unwindstack/MachineX86_64.h>
28 #include <unwindstack/Maps.h>
29 #include <unwindstack/Regs.h>
30 #include <unwindstack/RegsArm.h>
31 #include <unwindstack/RegsArm64.h>
32 #include <unwindstack/RegsX86.h>
33 #include <unwindstack/RegsX86_64.h>
34 #include <unwindstack/Unwinder.h>
35 #include <unwindstack/UserArm.h>
36 #include <unwindstack/UserArm64.h>
37 #include <unwindstack/UserX86.h>
38 #include <unwindstack/UserX86_64.h>
39
40 #include "environment.h"
41 #include "perf_regs.h"
42 #include "read_apk.h"
43 #include "thread_tree.h"
44
45 static_assert(simpleperf::map_flags::PROT_JIT_SYMFILE_MAP ==
46 unwindstack::MAPS_FLAGS_JIT_SYMFILE_MAP, "");
47
48 namespace simpleperf {
49
50 // Max frames seen so far is 463, in http://b/110923759.
51 static constexpr size_t MAX_UNWINDING_FRAMES = 512;
52
GetBacktraceRegs(const RegSet & regs)53 static unwindstack::Regs* GetBacktraceRegs(const RegSet& regs) {
54 switch (regs.arch) {
55 case ARCH_ARM: {
56 unwindstack::arm_user_regs arm_user_regs;
57 memset(&arm_user_regs, 0, sizeof(arm_user_regs));
58 static_assert(
59 static_cast<int>(unwindstack::ARM_REG_R0) == static_cast<int>(PERF_REG_ARM_R0), "");
60 static_assert(
61 static_cast<int>(unwindstack::ARM_REG_LAST) == static_cast<int>(PERF_REG_ARM_MAX), "");
62 for (size_t i = unwindstack::ARM_REG_R0; i < unwindstack::ARM_REG_LAST; ++i) {
63 arm_user_regs.regs[i] = static_cast<uint32_t>(regs.data[i]);
64 }
65 return unwindstack::RegsArm::Read(&arm_user_regs);
66 }
67 case ARCH_ARM64: {
68 unwindstack::arm64_user_regs arm64_user_regs;
69 memset(&arm64_user_regs, 0, sizeof(arm64_user_regs));
70 static_assert(
71 static_cast<int>(unwindstack::ARM64_REG_R0) == static_cast<int>(PERF_REG_ARM64_X0), "");
72 static_assert(
73 static_cast<int>(unwindstack::ARM64_REG_R30) == static_cast<int>(PERF_REG_ARM64_LR), "");
74 memcpy(&arm64_user_regs.regs[unwindstack::ARM64_REG_R0], ®s.data[PERF_REG_ARM64_X0],
75 sizeof(uint64_t) * (PERF_REG_ARM64_LR - PERF_REG_ARM64_X0 + 1));
76 arm64_user_regs.sp = regs.data[PERF_REG_ARM64_SP];
77 arm64_user_regs.pc = regs.data[PERF_REG_ARM64_PC];
78 return unwindstack::RegsArm64::Read(&arm64_user_regs);
79 }
80 case ARCH_X86_32: {
81 unwindstack::x86_user_regs x86_user_regs;
82 memset(&x86_user_regs, 0, sizeof(x86_user_regs));
83 x86_user_regs.eax = static_cast<uint32_t>(regs.data[PERF_REG_X86_AX]);
84 x86_user_regs.ebx = static_cast<uint32_t>(regs.data[PERF_REG_X86_BX]);
85 x86_user_regs.ecx = static_cast<uint32_t>(regs.data[PERF_REG_X86_CX]);
86 x86_user_regs.edx = static_cast<uint32_t>(regs.data[PERF_REG_X86_DX]);
87 x86_user_regs.ebp = static_cast<uint32_t>(regs.data[PERF_REG_X86_BP]);
88 x86_user_regs.edi = static_cast<uint32_t>(regs.data[PERF_REG_X86_DI]);
89 x86_user_regs.esi = static_cast<uint32_t>(regs.data[PERF_REG_X86_SI]);
90 x86_user_regs.esp = static_cast<uint32_t>(regs.data[PERF_REG_X86_SP]);
91 x86_user_regs.eip = static_cast<uint32_t>(regs.data[PERF_REG_X86_IP]);
92 return unwindstack::RegsX86::Read(&x86_user_regs);
93 }
94 case ARCH_X86_64: {
95 unwindstack::x86_64_user_regs x86_64_user_regs;
96 memset(&x86_64_user_regs, 0, sizeof(x86_64_user_regs));
97 x86_64_user_regs.rax = regs.data[PERF_REG_X86_AX];
98 x86_64_user_regs.rbx = regs.data[PERF_REG_X86_BX];
99 x86_64_user_regs.rcx = regs.data[PERF_REG_X86_CX];
100 x86_64_user_regs.rdx = regs.data[PERF_REG_X86_DX];
101 x86_64_user_regs.r8 = regs.data[PERF_REG_X86_R8];
102 x86_64_user_regs.r9 = regs.data[PERF_REG_X86_R9];
103 x86_64_user_regs.r10 = regs.data[PERF_REG_X86_R10];
104 x86_64_user_regs.r11 = regs.data[PERF_REG_X86_R11];
105 x86_64_user_regs.r12 = regs.data[PERF_REG_X86_R12];
106 x86_64_user_regs.r13 = regs.data[PERF_REG_X86_R13];
107 x86_64_user_regs.r14 = regs.data[PERF_REG_X86_R14];
108 x86_64_user_regs.r15 = regs.data[PERF_REG_X86_R15];
109 x86_64_user_regs.rdi = regs.data[PERF_REG_X86_DI];
110 x86_64_user_regs.rsi = regs.data[PERF_REG_X86_SI];
111 x86_64_user_regs.rbp = regs.data[PERF_REG_X86_BP];
112 x86_64_user_regs.rsp = regs.data[PERF_REG_X86_SP];
113 x86_64_user_regs.rip = regs.data[PERF_REG_X86_IP];
114 return unwindstack::RegsX86_64::Read(&x86_64_user_regs);
115 }
116 default:
117 return nullptr;
118 }
119 }
120
CreateMapInfo(const MapEntry * entry)121 static unwindstack::MapInfo* CreateMapInfo(const MapEntry* entry) {
122 const char* name = entry->dso->GetDebugFilePath().c_str();
123 uint64_t pgoff = entry->pgoff;
124 auto tuple = SplitUrlInApk(entry->dso->GetDebugFilePath());
125 if (std::get<0>(tuple)) {
126 // The unwinder does not understand the ! format, so change back to
127 // the previous format (apk, offset).
128 EmbeddedElf* elf = ApkInspector::FindElfInApkByName(std::get<1>(tuple), std::get<2>(tuple));
129 if (elf != nullptr) {
130 name = elf->filepath().c_str();
131 pgoff += elf->entry_offset();
132 }
133 }
134 return new unwindstack::MapInfo(nullptr, entry->start_addr, entry->get_end_addr(), pgoff,
135 PROT_READ | entry->flags, name);
136 }
137
138 class UnwindMaps : public unwindstack::Maps {
139 public:
140 void UpdateMaps(const MapSet& map_set);
141
142 private:
143 uint64_t version_ = 0u;
144 std::vector<const MapEntry*> entries_;
145 };
146
UpdateMaps(const MapSet & map_set)147 void UnwindMaps::UpdateMaps(const MapSet& map_set) {
148 if (version_ == map_set.version) {
149 return;
150 }
151 version_ = map_set.version;
152 size_t i = 0;
153 size_t old_size = entries_.size();
154 for (auto it = map_set.maps.begin(); it != map_set.maps.end();) {
155 const MapEntry* entry = it->second;
156 if (i < old_size && entry == entries_[i]) {
157 i++;
158 ++it;
159 } else if (i == old_size || entry->start_addr <= entries_[i]->start_addr) {
160 // Add an entry.
161 entries_.push_back(entry);
162 maps_.emplace_back(CreateMapInfo(entry));
163 ++it;
164 } else {
165 // Remove an entry.
166 entries_[i] = nullptr;
167 maps_[i++] = nullptr;
168 }
169 }
170 while (i < old_size) {
171 entries_[i] = nullptr;
172 maps_[i++] = nullptr;
173 }
174 std::sort(entries_.begin(), entries_.end(), [](const auto& e1, const auto& e2) {
175 if (e1 == nullptr || e2 == nullptr) {
176 return e1 != nullptr;
177 }
178 return e1->start_addr < e2->start_addr;
179 });
180 std::sort(maps_.begin(), maps_.end(),
181 [](const auto& m1, const auto& m2) {
182 if (m1 == nullptr || m2 == nullptr) {
183 return m1 != nullptr;
184 }
185 return m1->start < m2->start;
186 });
187 entries_.resize(map_set.maps.size());
188 maps_.resize(map_set.maps.size());
189 // prev_map is needed by libunwindstack to find the start of an embedded lib in an apk.
190 // See http://b/120981155.
191 for (size_t i = 1; i < maps_.size(); ++i) {
192 maps_[i]->prev_map = maps_[i-1].get();
193 }
194 }
195
196 class OfflineUnwinderImpl : public OfflineUnwinder {
197 public:
OfflineUnwinderImpl(bool collect_stat)198 OfflineUnwinderImpl(bool collect_stat) : collect_stat_(collect_stat) {
199 unwindstack::Elf::SetCachingEnabled(true);
200 }
201
202 bool UnwindCallChain(const ThreadEntry& thread, const RegSet& regs, const char* stack,
203 size_t stack_size, std::vector<uint64_t>* ips,
204 std::vector<uint64_t>* sps) override;
205
206 private:
207 bool collect_stat_;
208 std::unordered_map<pid_t, UnwindMaps> cached_maps_;
209 };
210
UnwindCallChain(const ThreadEntry & thread,const RegSet & regs,const char * stack,size_t stack_size,std::vector<uint64_t> * ips,std::vector<uint64_t> * sps)211 bool OfflineUnwinderImpl::UnwindCallChain(const ThreadEntry& thread, const RegSet& regs,
212 const char* stack, size_t stack_size,
213 std::vector<uint64_t>* ips, std::vector<uint64_t>* sps) {
214 uint64_t start_time;
215 if (collect_stat_) {
216 start_time = GetSystemClock();
217 }
218 is_callchain_broken_for_incomplete_jit_debug_info_ = false;
219 ips->clear();
220 sps->clear();
221 std::vector<uint64_t> result;
222 uint64_t sp_reg_value;
223 if (!regs.GetSpRegValue(&sp_reg_value)) {
224 LOG(ERROR) << "can't get sp reg value";
225 return false;
226 }
227 uint64_t stack_addr = sp_reg_value;
228
229 UnwindMaps& cached_map = cached_maps_[thread.pid];
230 cached_map.UpdateMaps(*thread.maps);
231 std::unique_ptr<unwindstack::Regs> unwind_regs(GetBacktraceRegs(regs));
232 if (!unwind_regs) {
233 return false;
234 }
235 unwindstack::Unwinder unwinder(
236 MAX_UNWINDING_FRAMES, &cached_map, unwind_regs.get(),
237 unwindstack::Memory::CreateOfflineMemory(reinterpret_cast<const uint8_t*>(stack), stack_addr,
238 stack_addr + stack_size));
239 unwinder.SetResolveNames(false);
240 unwinder.Unwind();
241 size_t last_jit_method_frame = UINT_MAX;
242 for (auto& frame : unwinder.frames()) {
243 // Unwinding in arm architecture can return 0 pc address.
244
245 // If frame.map.start == 0, this frame doesn't hit any map, it could be:
246 // 1. In an executable map not backed by a file. Note that RecordCommand::ShouldOmitRecord()
247 // may omit maps only exist memory.
248 // 2. An incorrectly unwound frame. Like caused by invalid stack data, as in
249 // SampleRecord::GetValidStackSize(). Or caused by incomplete JIT debug info.
250 // We want to remove this frame and callchains following it in either case.
251 if (frame.pc == 0 || frame.map_start == 0) {
252 is_callchain_broken_for_incomplete_jit_debug_info_ = true;
253 break;
254 }
255 if (frame.map_flags & unwindstack::MAPS_FLAGS_JIT_SYMFILE_MAP) {
256 last_jit_method_frame = ips->size();
257 }
258 ips->push_back(frame.pc);
259 sps->push_back(frame.sp);
260 }
261 // If the unwound frames stop near to a JITed method, it may be caused by incomplete JIT debug
262 // info.
263 if (last_jit_method_frame != UINT_MAX && last_jit_method_frame + 3 > ips->size()) {
264 is_callchain_broken_for_incomplete_jit_debug_info_ = true;
265 }
266
267 uint64_t ip_reg_value;
268 if (!regs.GetIpRegValue(&ip_reg_value)) {
269 LOG(ERROR) << "can't get ip reg value";
270 return false;
271 }
272 if (ips->empty()) {
273 ips->push_back(ip_reg_value);
274 sps->push_back(sp_reg_value);
275 } else {
276 // Check if the unwinder returns ip reg value as the first ip address in callstack.
277 CHECK_EQ((*ips)[0], ip_reg_value);
278 }
279 if (collect_stat_) {
280 unwinding_result_.used_time = GetSystemClock() - start_time;
281 switch (unwinder.LastErrorCode()) {
282 case unwindstack::ERROR_MAX_FRAMES_EXCEEDED:
283 unwinding_result_.stop_reason = UnwindingResult::EXCEED_MAX_FRAMES_LIMIT;
284 break;
285 case unwindstack::ERROR_MEMORY_INVALID: {
286 uint64_t addr = unwinder.LastErrorAddress();
287 // Because we don't have precise stack range here, just guess an addr is in stack
288 // if sp - 128K <= addr <= sp.
289 if (addr <= stack_addr && addr >= stack_addr - 128 * 1024) {
290 unwinding_result_.stop_reason = UnwindingResult::ACCESS_STACK_FAILED;
291 } else {
292 unwinding_result_.stop_reason = UnwindingResult::ACCESS_MEM_FAILED;
293 }
294 unwinding_result_.stop_info.addr = addr;
295 break;
296 }
297 case unwindstack::ERROR_INVALID_MAP:
298 unwinding_result_.stop_reason = UnwindingResult::MAP_MISSING;
299 break;
300 default:
301 unwinding_result_.stop_reason = UnwindingResult::UNKNOWN_REASON;
302 break;
303 }
304 unwinding_result_.stack_start = stack_addr;
305 unwinding_result_.stack_end = stack_addr + stack_size;
306 }
307 return true;
308 }
309
Create(bool collect_stat)310 std::unique_ptr<OfflineUnwinder> OfflineUnwinder::Create(bool collect_stat) {
311 return std::unique_ptr<OfflineUnwinder>(new OfflineUnwinderImpl(collect_stat));
312 }
313
314 } // namespace simpleperf
315