1 /*
2 * Copyright (C) 2017 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
19 #include <functional>
20
21 #include <unwindstack/Elf.h>
22 #include <unwindstack/MachineMips.h>
23 #include <unwindstack/MapInfo.h>
24 #include <unwindstack/Memory.h>
25 #include <unwindstack/RegsMips.h>
26 #include <unwindstack/UcontextMips.h>
27 #include <unwindstack/UserMips.h>
28
29 namespace unwindstack {
30
RegsMips()31 RegsMips::RegsMips()
32 : RegsImpl<uint32_t>(MIPS_REG_LAST, Location(LOCATION_REGISTER, MIPS_REG_RA)) {}
33
Arch()34 ArchEnum RegsMips::Arch() {
35 return ARCH_MIPS;
36 }
37
pc()38 uint64_t RegsMips::pc() {
39 return regs_[MIPS_REG_PC];
40 }
41
sp()42 uint64_t RegsMips::sp() {
43 return regs_[MIPS_REG_SP];
44 }
45
set_pc(uint64_t pc)46 void RegsMips::set_pc(uint64_t pc) {
47 regs_[MIPS_REG_PC] = static_cast<uint32_t>(pc);
48 }
49
set_sp(uint64_t sp)50 void RegsMips::set_sp(uint64_t sp) {
51 regs_[MIPS_REG_SP] = static_cast<uint32_t>(sp);
52 }
53
GetPcAdjustment(uint64_t rel_pc,Elf *)54 uint64_t RegsMips::GetPcAdjustment(uint64_t rel_pc, Elf*) {
55 if (rel_pc < 8) {
56 return 0;
57 }
58 // For now, just assume no compact branches
59 return 8;
60 }
61
SetPcFromReturnAddress(Memory *)62 bool RegsMips::SetPcFromReturnAddress(Memory*) {
63 uint32_t ra = regs_[MIPS_REG_RA];
64 if (regs_[MIPS_REG_PC] == ra) {
65 return false;
66 }
67
68 regs_[MIPS_REG_PC] = ra;
69 return true;
70 }
71
IterateRegisters(std::function<void (const char *,uint64_t)> fn)72 void RegsMips::IterateRegisters(std::function<void(const char*, uint64_t)> fn) {
73 fn("r0", regs_[MIPS_REG_R0]);
74 fn("r1", regs_[MIPS_REG_R1]);
75 fn("r2", regs_[MIPS_REG_R2]);
76 fn("r3", regs_[MIPS_REG_R3]);
77 fn("r4", regs_[MIPS_REG_R4]);
78 fn("r5", regs_[MIPS_REG_R5]);
79 fn("r6", regs_[MIPS_REG_R6]);
80 fn("r7", regs_[MIPS_REG_R7]);
81 fn("r8", regs_[MIPS_REG_R8]);
82 fn("r9", regs_[MIPS_REG_R9]);
83 fn("r10", regs_[MIPS_REG_R10]);
84 fn("r11", regs_[MIPS_REG_R11]);
85 fn("r12", regs_[MIPS_REG_R12]);
86 fn("r13", regs_[MIPS_REG_R13]);
87 fn("r14", regs_[MIPS_REG_R14]);
88 fn("r15", regs_[MIPS_REG_R15]);
89 fn("r16", regs_[MIPS_REG_R16]);
90 fn("r17", regs_[MIPS_REG_R17]);
91 fn("r18", regs_[MIPS_REG_R18]);
92 fn("r19", regs_[MIPS_REG_R19]);
93 fn("r20", regs_[MIPS_REG_R20]);
94 fn("r21", regs_[MIPS_REG_R21]);
95 fn("r22", regs_[MIPS_REG_R22]);
96 fn("r23", regs_[MIPS_REG_R23]);
97 fn("r24", regs_[MIPS_REG_R24]);
98 fn("r25", regs_[MIPS_REG_R25]);
99 fn("r26", regs_[MIPS_REG_R26]);
100 fn("r27", regs_[MIPS_REG_R27]);
101 fn("r28", regs_[MIPS_REG_R28]);
102 fn("sp", regs_[MIPS_REG_SP]);
103 fn("r30", regs_[MIPS_REG_R30]);
104 fn("ra", regs_[MIPS_REG_RA]);
105 fn("pc", regs_[MIPS_REG_PC]);
106 }
107
Read(void * remote_data)108 Regs* RegsMips::Read(void* remote_data) {
109 mips_user_regs* user = reinterpret_cast<mips_user_regs*>(remote_data);
110 RegsMips* regs = new RegsMips();
111 uint32_t* reg_data = reinterpret_cast<uint32_t*>(regs->RawData());
112
113 memcpy(regs->RawData(), &user->regs[MIPS32_EF_R0], (MIPS_REG_R31 + 1) * sizeof(uint32_t));
114
115 reg_data[MIPS_REG_PC] = user->regs[MIPS32_EF_CP0_EPC];
116 return regs;
117 }
118
CreateFromUcontext(void * ucontext)119 Regs* RegsMips::CreateFromUcontext(void* ucontext) {
120 mips_ucontext_t* mips_ucontext = reinterpret_cast<mips_ucontext_t*>(ucontext);
121
122 RegsMips* regs = new RegsMips();
123 // Copy 64 bit sc_regs over to 32 bit regs
124 for (int i = 0; i < 32; i++) {
125 (*regs)[MIPS_REG_R0 + i] = mips_ucontext->uc_mcontext.sc_regs[i];
126 }
127 (*regs)[MIPS_REG_PC] = mips_ucontext->uc_mcontext.sc_pc;
128 return regs;
129 }
130
StepIfSignalHandler(uint64_t rel_pc,Elf * elf,Memory * process_memory)131 bool RegsMips::StepIfSignalHandler(uint64_t rel_pc, Elf* elf, Memory* process_memory) {
132 uint64_t data;
133 uint64_t offset = 0;
134 Memory* elf_memory = elf->memory();
135 // Read from elf memory since it is usually more expensive to read from
136 // process memory.
137 if (!elf_memory->Read(rel_pc, &data, sizeof(data))) {
138 return false;
139 }
140
141 // Look for the kernel sigreturn functions.
142 // __vdso_rt_sigreturn:
143 // 0x24021061 li v0, 0x1061
144 // 0x0000000c syscall
145 // __vdso_sigreturn:
146 // 0x24021017 li v0, 0x1017
147 // 0x0000000c syscall
148 if (data == 0x0000000c24021061ULL) {
149 // vdso_rt_sigreturn => read rt_sigframe
150 // offset = siginfo offset + sizeof(siginfo) + uc_mcontext offset + sc_pc offset
151 offset = 24 + 128 + 24 + 8;
152 } else if (data == 0x0000000c24021017LL) {
153 // vdso_sigreturn => read sigframe
154 // offset = sigcontext offset + sc_pc offset
155 offset = 24 + 8;
156 } else {
157 return false;
158 }
159
160 // read sc_pc and sc_regs[32] from stack
161 uint64_t values[MIPS_REG_LAST];
162 if (!process_memory->Read(regs_[MIPS_REG_SP] + offset, values, sizeof(values))) {
163 return false;
164 }
165
166 // Copy 64 bit sc_pc over to 32 bit regs_[MIPS_REG_PC]
167 regs_[MIPS_REG_PC] = values[0];
168
169 // Copy 64 bit sc_regs over to 32 bit regs
170 for (int i = 0; i < 32; i++) {
171 regs_[MIPS_REG_R0 + i] = values[1 + i];
172 }
173 return true;
174 }
175
Clone()176 Regs* RegsMips::Clone() {
177 return new RegsMips(*this);
178 }
179
180 } // namespace unwindstack
181