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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 <stdint.h>
18 #include <string.h>
19 
20 #include <functional>
21 
22 #include <unwindstack/Elf.h>
23 #include <unwindstack/MachineArm64.h>
24 #include <unwindstack/MapInfo.h>
25 #include <unwindstack/Memory.h>
26 #include <unwindstack/RegsArm64.h>
27 #include <unwindstack/UcontextArm64.h>
28 #include <unwindstack/UserArm64.h>
29 
30 namespace unwindstack {
31 
RegsArm64()32 RegsArm64::RegsArm64()
33     : RegsImpl<uint64_t>(ARM64_REG_LAST, Location(LOCATION_REGISTER, ARM64_REG_LR)) {}
34 
Arch()35 ArchEnum RegsArm64::Arch() {
36   return ARCH_ARM64;
37 }
38 
pc()39 uint64_t RegsArm64::pc() {
40   return regs_[ARM64_REG_PC];
41 }
42 
sp()43 uint64_t RegsArm64::sp() {
44   return regs_[ARM64_REG_SP];
45 }
46 
set_pc(uint64_t pc)47 void RegsArm64::set_pc(uint64_t pc) {
48   regs_[ARM64_REG_PC] = pc;
49 }
50 
set_sp(uint64_t sp)51 void RegsArm64::set_sp(uint64_t sp) {
52   regs_[ARM64_REG_SP] = sp;
53 }
54 
GetPcAdjustment(uint64_t rel_pc,Elf *)55 uint64_t RegsArm64::GetPcAdjustment(uint64_t rel_pc, Elf*) {
56   if (rel_pc < 4) {
57     return 0;
58   }
59   return 4;
60 }
61 
SetPcFromReturnAddress(Memory *)62 bool RegsArm64::SetPcFromReturnAddress(Memory*) {
63   uint64_t lr = regs_[ARM64_REG_LR];
64   if (regs_[ARM64_REG_PC] == lr) {
65     return false;
66   }
67 
68   regs_[ARM64_REG_PC] = lr;
69   return true;
70 }
71 
IterateRegisters(std::function<void (const char *,uint64_t)> fn)72 void RegsArm64::IterateRegisters(std::function<void(const char*, uint64_t)> fn) {
73   fn("x0", regs_[ARM64_REG_R0]);
74   fn("x1", regs_[ARM64_REG_R1]);
75   fn("x2", regs_[ARM64_REG_R2]);
76   fn("x3", regs_[ARM64_REG_R3]);
77   fn("x4", regs_[ARM64_REG_R4]);
78   fn("x5", regs_[ARM64_REG_R5]);
79   fn("x6", regs_[ARM64_REG_R6]);
80   fn("x7", regs_[ARM64_REG_R7]);
81   fn("x8", regs_[ARM64_REG_R8]);
82   fn("x9", regs_[ARM64_REG_R9]);
83   fn("x10", regs_[ARM64_REG_R10]);
84   fn("x11", regs_[ARM64_REG_R11]);
85   fn("x12", regs_[ARM64_REG_R12]);
86   fn("x13", regs_[ARM64_REG_R13]);
87   fn("x14", regs_[ARM64_REG_R14]);
88   fn("x15", regs_[ARM64_REG_R15]);
89   fn("x16", regs_[ARM64_REG_R16]);
90   fn("x17", regs_[ARM64_REG_R17]);
91   fn("x18", regs_[ARM64_REG_R18]);
92   fn("x19", regs_[ARM64_REG_R19]);
93   fn("x20", regs_[ARM64_REG_R20]);
94   fn("x21", regs_[ARM64_REG_R21]);
95   fn("x22", regs_[ARM64_REG_R22]);
96   fn("x23", regs_[ARM64_REG_R23]);
97   fn("x24", regs_[ARM64_REG_R24]);
98   fn("x25", regs_[ARM64_REG_R25]);
99   fn("x26", regs_[ARM64_REG_R26]);
100   fn("x27", regs_[ARM64_REG_R27]);
101   fn("x28", regs_[ARM64_REG_R28]);
102   fn("x29", regs_[ARM64_REG_R29]);
103   fn("sp", regs_[ARM64_REG_SP]);
104   fn("lr", regs_[ARM64_REG_LR]);
105   fn("pc", regs_[ARM64_REG_PC]);
106 }
107 
Read(void * remote_data)108 Regs* RegsArm64::Read(void* remote_data) {
109   arm64_user_regs* user = reinterpret_cast<arm64_user_regs*>(remote_data);
110 
111   RegsArm64* regs = new RegsArm64();
112   memcpy(regs->RawData(), &user->regs[0], (ARM64_REG_R31 + 1) * sizeof(uint64_t));
113   uint64_t* reg_data = reinterpret_cast<uint64_t*>(regs->RawData());
114   reg_data[ARM64_REG_PC] = user->pc;
115   reg_data[ARM64_REG_SP] = user->sp;
116   return regs;
117 }
118 
CreateFromUcontext(void * ucontext)119 Regs* RegsArm64::CreateFromUcontext(void* ucontext) {
120   arm64_ucontext_t* arm64_ucontext = reinterpret_cast<arm64_ucontext_t*>(ucontext);
121 
122   RegsArm64* regs = new RegsArm64();
123   memcpy(regs->RawData(), &arm64_ucontext->uc_mcontext.regs[0], ARM64_REG_LAST * sizeof(uint64_t));
124   return regs;
125 }
126 
StepIfSignalHandler(uint64_t rel_pc,Elf * elf,Memory * process_memory)127 bool RegsArm64::StepIfSignalHandler(uint64_t rel_pc, Elf* elf, Memory* process_memory) {
128   uint64_t data;
129   Memory* elf_memory = elf->memory();
130   // Read from elf memory since it is usually more expensive to read from
131   // process memory.
132   if (!elf_memory->ReadFully(rel_pc, &data, sizeof(data))) {
133     return false;
134   }
135 
136   // Look for the kernel sigreturn function.
137   // __kernel_rt_sigreturn:
138   // 0xd2801168     mov x8, #0x8b
139   // 0xd4000001     svc #0x0
140   if (data != 0xd4000001d2801168ULL) {
141     return false;
142   }
143 
144   // SP + sizeof(siginfo_t) + uc_mcontext offset + X0 offset.
145   if (!process_memory->ReadFully(regs_[ARM64_REG_SP] + 0x80 + 0xb0 + 0x08, regs_.data(),
146                                  sizeof(uint64_t) * ARM64_REG_LAST)) {
147     return false;
148   }
149   return true;
150 }
151 
Clone()152 Regs* RegsArm64::Clone() {
153   return new RegsArm64(*this);
154 }
155 
156 }  // namespace unwindstack
157