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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 #include <string.h>
19 
20 #include <functional>
21 
22 #include <unwindstack/Elf.h>
23 #include <unwindstack/MachineMips64.h>
24 #include <unwindstack/MapInfo.h>
25 #include <unwindstack/Memory.h>
26 #include <unwindstack/RegsMips64.h>
27 #include <unwindstack/UcontextMips64.h>
28 #include <unwindstack/UserMips64.h>
29 
30 namespace unwindstack {
31 
RegsMips64()32 RegsMips64::RegsMips64()
33     : RegsImpl<uint64_t>(MIPS64_REG_LAST, Location(LOCATION_REGISTER, MIPS64_REG_RA)) {}
34 
Arch()35 ArchEnum RegsMips64::Arch() {
36   return ARCH_MIPS64;
37 }
38 
pc()39 uint64_t RegsMips64::pc() {
40   return regs_[MIPS64_REG_PC];
41 }
42 
sp()43 uint64_t RegsMips64::sp() {
44   return regs_[MIPS64_REG_SP];
45 }
46 
set_pc(uint64_t pc)47 void RegsMips64::set_pc(uint64_t pc) {
48   regs_[MIPS64_REG_PC] = pc;
49 }
50 
set_sp(uint64_t sp)51 void RegsMips64::set_sp(uint64_t sp) {
52   regs_[MIPS64_REG_SP] = sp;
53 }
54 
GetPcAdjustment(uint64_t rel_pc,Elf *)55 uint64_t RegsMips64::GetPcAdjustment(uint64_t rel_pc, Elf*) {
56   if (rel_pc < 8) {
57     return 0;
58   }
59   // For now, just assume no compact branches
60   return 8;
61 }
62 
SetPcFromReturnAddress(Memory *)63 bool RegsMips64::SetPcFromReturnAddress(Memory*) {
64   uint64_t ra = regs_[MIPS64_REG_RA];
65   if (regs_[MIPS64_REG_PC] == ra) {
66     return false;
67   }
68 
69   regs_[MIPS64_REG_PC] = ra;
70   return true;
71 }
72 
IterateRegisters(std::function<void (const char *,uint64_t)> fn)73 void RegsMips64::IterateRegisters(std::function<void(const char*, uint64_t)> fn) {
74   fn("r0", regs_[MIPS64_REG_R0]);
75   fn("r1", regs_[MIPS64_REG_R1]);
76   fn("r2", regs_[MIPS64_REG_R2]);
77   fn("r3", regs_[MIPS64_REG_R3]);
78   fn("r4", regs_[MIPS64_REG_R4]);
79   fn("r5", regs_[MIPS64_REG_R5]);
80   fn("r6", regs_[MIPS64_REG_R6]);
81   fn("r7", regs_[MIPS64_REG_R7]);
82   fn("r8", regs_[MIPS64_REG_R8]);
83   fn("r9", regs_[MIPS64_REG_R9]);
84   fn("r10", regs_[MIPS64_REG_R10]);
85   fn("r11", regs_[MIPS64_REG_R11]);
86   fn("r12", regs_[MIPS64_REG_R12]);
87   fn("r13", regs_[MIPS64_REG_R13]);
88   fn("r14", regs_[MIPS64_REG_R14]);
89   fn("r15", regs_[MIPS64_REG_R15]);
90   fn("r16", regs_[MIPS64_REG_R16]);
91   fn("r17", regs_[MIPS64_REG_R17]);
92   fn("r18", regs_[MIPS64_REG_R18]);
93   fn("r19", regs_[MIPS64_REG_R19]);
94   fn("r20", regs_[MIPS64_REG_R20]);
95   fn("r21", regs_[MIPS64_REG_R21]);
96   fn("r22", regs_[MIPS64_REG_R22]);
97   fn("r23", regs_[MIPS64_REG_R23]);
98   fn("r24", regs_[MIPS64_REG_R24]);
99   fn("r25", regs_[MIPS64_REG_R25]);
100   fn("r26", regs_[MIPS64_REG_R26]);
101   fn("r27", regs_[MIPS64_REG_R27]);
102   fn("r28", regs_[MIPS64_REG_R28]);
103   fn("sp", regs_[MIPS64_REG_SP]);
104   fn("r30", regs_[MIPS64_REG_R30]);
105   fn("ra", regs_[MIPS64_REG_RA]);
106   fn("pc", regs_[MIPS64_REG_PC]);
107 }
108 
Read(void * remote_data)109 Regs* RegsMips64::Read(void* remote_data) {
110   mips64_user_regs* user = reinterpret_cast<mips64_user_regs*>(remote_data);
111   RegsMips64* regs = new RegsMips64();
112   uint64_t* reg_data = reinterpret_cast<uint64_t*>(regs->RawData());
113 
114   memcpy(regs->RawData(), &user->regs[MIPS64_EF_R0], (MIPS64_REG_R31 + 1) * sizeof(uint64_t));
115 
116   reg_data[MIPS64_REG_PC] = user->regs[MIPS64_EF_CP0_EPC];
117   return regs;
118 }
119 
CreateFromUcontext(void * ucontext)120 Regs* RegsMips64::CreateFromUcontext(void* ucontext) {
121   mips64_ucontext_t* mips64_ucontext = reinterpret_cast<mips64_ucontext_t*>(ucontext);
122 
123   RegsMips64* regs = new RegsMips64();
124   // Copy 64 bit sc_regs over to 64 bit regs
125   memcpy(regs->RawData(), &mips64_ucontext->uc_mcontext.sc_regs[0], 32 * sizeof(uint64_t));
126   (*regs)[MIPS64_REG_PC] = mips64_ucontext->uc_mcontext.sc_pc;
127   return regs;
128 }
129 
StepIfSignalHandler(uint64_t rel_pc,Elf * elf,Memory * process_memory)130 bool RegsMips64::StepIfSignalHandler(uint64_t rel_pc, Elf* elf, Memory* process_memory) {
131   uint64_t data;
132   Memory* elf_memory = elf->memory();
133   // Read from elf memory since it is usually more expensive to read from
134   // process memory.
135   if (!elf_memory->Read(rel_pc, &data, sizeof(data))) {
136     return false;
137   }
138 
139   // Look for the kernel sigreturn function.
140   // __vdso_rt_sigreturn:
141   // 0x2402145b     li  v0, 0x145b
142   // 0x0000000c     syscall
143   if (data != 0x0000000c2402145bULL) {
144     return false;
145   }
146 
147   // vdso_rt_sigreturn => read rt_sigframe
148   // offset = siginfo offset + sizeof(siginfo) + uc_mcontext offset
149   // read 64 bit sc_regs[32] from stack into 64 bit regs_
150   uint64_t sp = regs_[MIPS64_REG_SP];
151   if (!process_memory->Read(sp + 24 + 128 + 40, regs_.data(),
152                             sizeof(uint64_t) * (MIPS64_REG_LAST - 1))) {
153     return false;
154   }
155 
156   // offset = siginfo offset + sizeof(siginfo) + uc_mcontext offset + sc_pc offset
157   // read 64 bit sc_pc from stack into 64 bit regs_[MIPS64_REG_PC]
158   if (!process_memory->Read(sp + 24 + 128 + 40 + 576, &regs_[MIPS64_REG_PC], sizeof(uint64_t))) {
159     return false;
160   }
161   return true;
162 }
163 
Clone()164 Regs* RegsMips64::Clone() {
165   return new RegsMips64(*this);
166 }
167 
168 }  // namespace unwindstack
169