1 /*
2 * Copyright (C) 2016 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 <errno.h>
18 #include <stdint.h>
19 #include <string.h>
20 #include <sys/ptrace.h>
21 #include <sys/uio.h>
22
23 #include <algorithm>
24 #include <vector>
25
26 #include <unwindstack/Elf.h>
27 #include <unwindstack/Log.h>
28 #include <unwindstack/MapInfo.h>
29 #include <unwindstack/Regs.h>
30 #include <unwindstack/RegsArm.h>
31 #include <unwindstack/RegsArm64.h>
32 #include <unwindstack/RegsRiscv64.h>
33 #include <unwindstack/RegsX86.h>
34 #include <unwindstack/RegsX86_64.h>
35 #include <unwindstack/UserArm.h>
36 #include <unwindstack/UserArm64.h>
37 #include <unwindstack/UserRiscv64.h>
38 #include <unwindstack/UserX86.h>
39 #include <unwindstack/UserX86_64.h>
40
41 namespace unwindstack {
42
43 // The largest user structure.
44 // constexpr size_t MAX_USER_REGS_SIZE = sizeof(mips64_user_regs) + 10;
45 static constexpr size_t kMaxUserRegsSize = std::max(
46 sizeof(arm_user_regs),
47 std::max(sizeof(arm64_user_regs), std::max(sizeof(x86_user_regs), sizeof(x86_64_user_regs))));
48
49 // This function assumes that reg_data is already aligned to a 64 bit value.
50 // If not this could crash with an unaligned access.
RemoteGet(pid_t pid,ErrorCode * error_code)51 Regs* Regs::RemoteGet(pid_t pid, ErrorCode* error_code) {
52 // Make the buffer large enough to contain the largest registers type.
53 std::vector<uint64_t> buffer(kMaxUserRegsSize / sizeof(uint64_t));
54 struct iovec io;
55 io.iov_base = buffer.data();
56 io.iov_len = buffer.size() * sizeof(uint64_t);
57
58 if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, reinterpret_cast<void*>(&io)) == -1) {
59 Log::Error("PTRACE_GETREGSET failed for pid %d: %s", pid, strerror(errno));
60 if (error_code != nullptr) {
61 *error_code = ERROR_PTRACE_CALL;
62 }
63 return nullptr;
64 }
65
66 // Infer the process architecture from the size of its register structure.
67 switch (io.iov_len) {
68 case sizeof(x86_user_regs):
69 return RegsX86::Read(buffer.data());
70 case sizeof(x86_64_user_regs):
71 return RegsX86_64::Read(buffer.data());
72 case sizeof(arm_user_regs):
73 return RegsArm::Read(buffer.data());
74 case sizeof(arm64_user_regs):
75 return RegsArm64::Read(buffer.data());
76 case sizeof(riscv64_user_regs):
77 return RegsRiscv64::Read(buffer.data());
78 }
79
80 Log::Error("No matching size of user regs structure for pid %d: size %zu", pid, io.iov_len);
81 if (error_code != nullptr) {
82 *error_code = ERROR_UNSUPPORTED;
83 }
84 return nullptr;
85 }
86
RemoteGetArch(pid_t pid,ErrorCode * error_code)87 ArchEnum Regs::RemoteGetArch(pid_t pid, ErrorCode* error_code) {
88 // Make the buffer large enough to contain the largest registers type.
89 std::vector<uint64_t> buffer(kMaxUserRegsSize / sizeof(uint64_t));
90 struct iovec io;
91 io.iov_base = buffer.data();
92 io.iov_len = buffer.size() * sizeof(uint64_t);
93
94 if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, reinterpret_cast<void*>(&io)) == -1) {
95 Log::Error("PTRACE_GETREGSET failed for pid %d: %s", pid, strerror(errno));
96 if (error_code != nullptr) {
97 *error_code = ERROR_PTRACE_CALL;
98 }
99 return ARCH_UNKNOWN;
100 }
101
102 // Infer the process architecture from the size of its register structure.
103 switch (io.iov_len) {
104 case sizeof(x86_user_regs):
105 return ARCH_X86;
106 case sizeof(x86_64_user_regs):
107 return ARCH_X86_64;
108 case sizeof(arm_user_regs):
109 return ARCH_ARM;
110 case sizeof(arm64_user_regs):
111 return ARCH_ARM64;
112 }
113
114 Log::Error("No matching size of user regs structure for pid %d: size %zu", pid, io.iov_len);
115 if (error_code != nullptr) {
116 *error_code = ERROR_UNSUPPORTED;
117 }
118 return ARCH_UNKNOWN;
119 }
120
CreateFromUcontext(ArchEnum arch,void * ucontext)121 Regs* Regs::CreateFromUcontext(ArchEnum arch, void* ucontext) {
122 switch (arch) {
123 case ARCH_X86:
124 return RegsX86::CreateFromUcontext(ucontext);
125 case ARCH_X86_64:
126 return RegsX86_64::CreateFromUcontext(ucontext);
127 case ARCH_ARM:
128 return RegsArm::CreateFromUcontext(ucontext);
129 case ARCH_ARM64:
130 return RegsArm64::CreateFromUcontext(ucontext);
131 case ARCH_RISCV64:
132 return RegsRiscv64::CreateFromUcontext(ucontext);
133 case ARCH_UNKNOWN:
134 default:
135 return nullptr;
136 }
137 }
138
CurrentArch()139 ArchEnum Regs::CurrentArch() {
140 #if defined(__arm__)
141 return ARCH_ARM;
142 #elif defined(__aarch64__)
143 return ARCH_ARM64;
144 #elif defined(__i386__)
145 return ARCH_X86;
146 #elif defined(__x86_64__)
147 return ARCH_X86_64;
148 #elif defined(__riscv)
149 return ARCH_RISCV64;
150 #else
151 abort();
152 #endif
153 }
154
CreateFromLocal()155 Regs* Regs::CreateFromLocal() {
156 Regs* regs;
157 #if defined(__arm__)
158 regs = new RegsArm();
159 #elif defined(__aarch64__)
160 regs = new RegsArm64();
161 #elif defined(__i386__)
162 regs = new RegsX86();
163 #elif defined(__x86_64__)
164 regs = new RegsX86_64();
165 #elif defined(__riscv)
166 regs = new RegsRiscv64();
167 #else
168 abort();
169 #endif
170 return regs;
171 }
172
GetPcAdjustment(uint64_t rel_pc,Elf * elf,ArchEnum arch)173 uint64_t GetPcAdjustment(uint64_t rel_pc, Elf* elf, ArchEnum arch) {
174 switch (arch) {
175 case ARCH_ARM: {
176 if (!elf->valid()) {
177 return 2;
178 }
179
180 uint64_t load_bias = elf->GetLoadBias();
181 if (rel_pc < load_bias) {
182 if (rel_pc < 2) {
183 return 0;
184 }
185 return 2;
186 }
187 uint64_t adjusted_rel_pc = rel_pc - load_bias;
188 if (adjusted_rel_pc < 5) {
189 if (adjusted_rel_pc < 2) {
190 return 0;
191 }
192 return 2;
193 }
194
195 if (adjusted_rel_pc & 1) {
196 // This is a thumb instruction, it could be 2 or 4 bytes.
197 uint32_t value;
198 if (!elf->memory()->ReadFully(adjusted_rel_pc - 5, &value, sizeof(value)) ||
199 (value & 0xe000f000) != 0xe000f000) {
200 return 2;
201 }
202 }
203 return 4;
204 }
205 case ARCH_ARM64:
206 case ARCH_RISCV64: {
207 if (rel_pc < 4) {
208 return 0;
209 }
210 return 4;
211 }
212 case ARCH_MIPS:
213 case ARCH_MIPS64: {
214 if (rel_pc < 8) {
215 return 0;
216 }
217 // For now, just assume no compact branches
218 return 8;
219 }
220 case ARCH_X86:
221 case ARCH_X86_64: {
222 if (rel_pc == 0) {
223 return 0;
224 }
225 return 1;
226 }
227 case ARCH_UNKNOWN:
228 return 0;
229 }
230 }
231
232 } // namespace unwindstack
233