1 //===-- NativeRegisterContextLinux.cpp --------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "NativeRegisterContextLinux.h"
11 
12 #include "lldb/Core/RegisterValue.h"
13 #include "lldb/Host/common/NativeProcessProtocol.h"
14 #include "lldb/Host/common/NativeThreadProtocol.h"
15 #include "lldb/Host/linux/Ptrace.h"
16 
17 #include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
18 
19 using namespace lldb_private;
20 using namespace lldb_private::process_linux;
21 
22 NativeRegisterContextLinux::NativeRegisterContextLinux(
23     NativeThreadProtocol &native_thread, uint32_t concrete_frame_idx,
24     RegisterInfoInterface *reg_info_interface_p)
25     : NativeRegisterContextRegisterInfo(native_thread, concrete_frame_idx,
26                                         reg_info_interface_p) {}
27 
28 lldb::ByteOrder NativeRegisterContextLinux::GetByteOrder() const {
29   // Get the target process whose privileged thread was used for the register
30   // read.
31   lldb::ByteOrder byte_order = lldb::eByteOrderInvalid;
32 
33   NativeProcessProtocolSP process_sp(m_thread.GetProcess());
34   if (!process_sp)
35     return byte_order;
36 
37   if (!process_sp->GetByteOrder(byte_order)) {
38     // FIXME log here
39   }
40 
41   return byte_order;
42 }
43 
44 Status NativeRegisterContextLinux::ReadRegisterRaw(uint32_t reg_index,
45                                                    RegisterValue &reg_value) {
46   const RegisterInfo *const reg_info = GetRegisterInfoAtIndex(reg_index);
47   if (!reg_info)
48     return Status("register %" PRIu32 " not found", reg_index);
49 
50   return DoReadRegisterValue(reg_info->byte_offset, reg_info->name,
51                              reg_info->byte_size, reg_value);
52 }
53 
54 Status
55 NativeRegisterContextLinux::WriteRegisterRaw(uint32_t reg_index,
56                                              const RegisterValue &reg_value) {
57   uint32_t reg_to_write = reg_index;
58   RegisterValue value_to_write = reg_value;
59 
60   // Check if this is a subregister of a full register.
61   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg_index);
62   if (reg_info->invalidate_regs &&
63       (reg_info->invalidate_regs[0] != LLDB_INVALID_REGNUM)) {
64     Status error;
65 
66     RegisterValue full_value;
67     uint32_t full_reg = reg_info->invalidate_regs[0];
68     const RegisterInfo *full_reg_info = GetRegisterInfoAtIndex(full_reg);
69 
70     // Read the full register.
71     error = ReadRegister(full_reg_info, full_value);
72     if (error.Fail())
73       return error;
74 
75     lldb::ByteOrder byte_order = GetByteOrder();
76     uint8_t dst[RegisterValue::kMaxRegisterByteSize];
77 
78     // Get the bytes for the full register.
79     const uint32_t dest_size = full_value.GetAsMemoryData(
80         full_reg_info, dst, sizeof(dst), byte_order, error);
81     if (error.Success() && dest_size) {
82       uint8_t src[RegisterValue::kMaxRegisterByteSize];
83 
84       // Get the bytes for the source data.
85       const uint32_t src_size = reg_value.GetAsMemoryData(
86           reg_info, src, sizeof(src), byte_order, error);
87       if (error.Success() && src_size && (src_size < dest_size)) {
88         // Copy the src bytes to the destination.
89         memcpy(dst + (reg_info->byte_offset & 0x1), src, src_size);
90         // Set this full register as the value to write.
91         value_to_write.SetBytes(dst, full_value.GetByteSize(), byte_order);
92         value_to_write.SetType(full_reg_info);
93         reg_to_write = full_reg;
94       }
95     }
96   }
97 
98   const RegisterInfo *const register_to_write_info_p =
99       GetRegisterInfoAtIndex(reg_to_write);
100   assert(register_to_write_info_p &&
101          "register to write does not have valid RegisterInfo");
102   if (!register_to_write_info_p)
103     return Status("NativeRegisterContextLinux::%s failed to get RegisterInfo "
104                   "for write register index %" PRIu32,
105                   __FUNCTION__, reg_to_write);
106 
107   return DoWriteRegisterValue(reg_info->byte_offset, reg_info->name, reg_value);
108 }
109 
110 Status NativeRegisterContextLinux::ReadGPR() {
111   void *buf = GetGPRBuffer();
112   if (!buf)
113     return Status("GPR buffer is NULL");
114   size_t buf_size = GetGPRSize();
115 
116   return DoReadGPR(buf, buf_size);
117 }
118 
119 Status NativeRegisterContextLinux::WriteGPR() {
120   void *buf = GetGPRBuffer();
121   if (!buf)
122     return Status("GPR buffer is NULL");
123   size_t buf_size = GetGPRSize();
124 
125   return DoWriteGPR(buf, buf_size);
126 }
127 
128 Status NativeRegisterContextLinux::ReadFPR() {
129   void *buf = GetFPRBuffer();
130   if (!buf)
131     return Status("FPR buffer is NULL");
132   size_t buf_size = GetFPRSize();
133 
134   return DoReadFPR(buf, buf_size);
135 }
136 
137 Status NativeRegisterContextLinux::WriteFPR() {
138   void *buf = GetFPRBuffer();
139   if (!buf)
140     return Status("FPR buffer is NULL");
141   size_t buf_size = GetFPRSize();
142 
143   return DoWriteFPR(buf, buf_size);
144 }
145 
146 Status NativeRegisterContextLinux::ReadRegisterSet(void *buf, size_t buf_size,
147                                                    unsigned int regset) {
148   return NativeProcessLinux::PtraceWrapper(PTRACE_GETREGSET, m_thread.GetID(),
149                                            static_cast<void *>(&regset), buf,
150                                            buf_size);
151 }
152 
153 Status NativeRegisterContextLinux::WriteRegisterSet(void *buf, size_t buf_size,
154                                                     unsigned int regset) {
155   return NativeProcessLinux::PtraceWrapper(PTRACE_SETREGSET, m_thread.GetID(),
156                                            static_cast<void *>(&regset), buf,
157                                            buf_size);
158 }
159 
160 Status NativeRegisterContextLinux::DoReadRegisterValue(uint32_t offset,
161                                                        const char *reg_name,
162                                                        uint32_t size,
163                                                        RegisterValue &value) {
164   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_REGISTERS));
165 
166   long data;
167   Status error = NativeProcessLinux::PtraceWrapper(
168       PTRACE_PEEKUSER, m_thread.GetID(), reinterpret_cast<void *>(offset),
169       nullptr, 0, &data);
170 
171   if (error.Success())
172     // First cast to an unsigned of the same size to avoid sign extension.
173     value.SetUInt(static_cast<unsigned long>(data), size);
174 
175   LLDB_LOG(log, "{0}: {1:x}", reg_name, data);
176   return error;
177 }
178 
179 Status NativeRegisterContextLinux::DoWriteRegisterValue(
180     uint32_t offset, const char *reg_name, const RegisterValue &value) {
181   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_REGISTERS));
182 
183   void *buf = reinterpret_cast<void *>(value.GetAsUInt64());
184   LLDB_LOG(log, "{0}: {1}", reg_name, buf);
185 
186   return NativeProcessLinux::PtraceWrapper(
187       PTRACE_POKEUSER, m_thread.GetID(), reinterpret_cast<void *>(offset), buf);
188 }
189 
190 Status NativeRegisterContextLinux::DoReadGPR(void *buf, size_t buf_size) {
191   return NativeProcessLinux::PtraceWrapper(PTRACE_GETREGS, m_thread.GetID(),
192                                            nullptr, buf, buf_size);
193 }
194 
195 Status NativeRegisterContextLinux::DoWriteGPR(void *buf, size_t buf_size) {
196   return NativeProcessLinux::PtraceWrapper(PTRACE_SETREGS, m_thread.GetID(),
197                                            nullptr, buf, buf_size);
198 }
199 
200 Status NativeRegisterContextLinux::DoReadFPR(void *buf, size_t buf_size) {
201   return NativeProcessLinux::PtraceWrapper(PTRACE_GETFPREGS, m_thread.GetID(),
202                                            nullptr, buf, buf_size);
203 }
204 
205 Status NativeRegisterContextLinux::DoWriteFPR(void *buf, size_t buf_size) {
206   return NativeProcessLinux::PtraceWrapper(PTRACE_SETFPREGS, m_thread.GetID(),
207                                            nullptr, buf, buf_size);
208 }
209