1 //===-- NativeRegisterContext.cpp -------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "lldb/Host/common/NativeRegisterContext.h"
10 
11 #include "lldb/Utility/Log.h"
12 #include "lldb/Utility/RegisterValue.h"
13 
14 #include "lldb/Host/PosixApi.h"
15 #include "lldb/Host/common/NativeProcessProtocol.h"
16 #include "lldb/Host/common/NativeThreadProtocol.h"
17 
18 using namespace lldb;
19 using namespace lldb_private;
20 
21 NativeRegisterContext::NativeRegisterContext(NativeThreadProtocol &thread)
22     : m_thread(thread) {}
23 
24 // Destructor
25 NativeRegisterContext::~NativeRegisterContext() {}
26 
27 // FIXME revisit invalidation, process stop ids, etc.  Right now we don't
28 // support caching in NativeRegisterContext.  We can do this later by utilizing
29 // NativeProcessProtocol::GetStopID () and adding a stop id to
30 // NativeRegisterContext.
31 
32 // void
33 // NativeRegisterContext::InvalidateIfNeeded (bool force) {
34 //     ProcessSP process_sp (m_thread.GetProcess());
35 //     bool invalidate = force;
36 //     uint32_t process_stop_id = UINT32_MAX;
37 
38 //     if (process_sp)
39 //         process_stop_id = process_sp->GetStopID();
40 //     else
41 //         invalidate = true;
42 
43 //     if (!invalidate)
44 //         invalidate = process_stop_id != GetStopID();
45 
46 //     if (invalidate)
47 //     {
48 //         InvalidateAllRegisters ();
49 //         SetStopID (process_stop_id);
50 //     }
51 // }
52 
53 const RegisterInfo *
54 NativeRegisterContext::GetRegisterInfoByName(llvm::StringRef reg_name,
55                                              uint32_t start_idx) {
56   if (reg_name.empty())
57     return nullptr;
58 
59   const uint32_t num_registers = GetRegisterCount();
60   for (uint32_t reg = start_idx; reg < num_registers; ++reg) {
61     const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
62 
63     if (reg_name.equals_lower(reg_info->name) ||
64         reg_name.equals_lower(reg_info->alt_name))
65       return reg_info;
66   }
67   return nullptr;
68 }
69 
70 const RegisterInfo *NativeRegisterContext::GetRegisterInfo(uint32_t kind,
71                                                            uint32_t num) {
72   const uint32_t reg_num = ConvertRegisterKindToRegisterNumber(kind, num);
73   if (reg_num == LLDB_INVALID_REGNUM)
74     return nullptr;
75   return GetRegisterInfoAtIndex(reg_num);
76 }
77 
78 const char *NativeRegisterContext::GetRegisterName(uint32_t reg) {
79   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
80   if (reg_info)
81     return reg_info->name;
82   return nullptr;
83 }
84 
85 const char *NativeRegisterContext::GetRegisterSetNameForRegisterAtIndex(
86     uint32_t reg_index) const {
87   const RegisterInfo *const reg_info = GetRegisterInfoAtIndex(reg_index);
88   if (!reg_info)
89     return nullptr;
90 
91   for (uint32_t set_index = 0; set_index < GetRegisterSetCount(); ++set_index) {
92     const RegisterSet *const reg_set = GetRegisterSet(set_index);
93     if (!reg_set)
94       continue;
95 
96     for (uint32_t reg_num_index = 0; reg_num_index < reg_set->num_registers;
97          ++reg_num_index) {
98       const uint32_t reg_num = reg_set->registers[reg_num_index];
99       // FIXME double check we're checking the right register kind here.
100       if (reg_info->kinds[RegisterKind::eRegisterKindLLDB] == reg_num) {
101         // The given register is a member of this register set.  Return the
102         // register set name.
103         return reg_set->name;
104       }
105     }
106   }
107 
108   // Didn't find it.
109   return nullptr;
110 }
111 
112 lldb::addr_t NativeRegisterContext::GetPC(lldb::addr_t fail_value) {
113   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
114 
115   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
116                                                      LLDB_REGNUM_GENERIC_PC);
117   if (log)
118     log->Printf("NativeRegisterContext::%s using reg index %" PRIu32
119                 " (default %" PRIu64 ")",
120                 __FUNCTION__, reg, fail_value);
121 
122   const uint64_t retval = ReadRegisterAsUnsigned(reg, fail_value);
123 
124   if (log)
125     log->Printf("NativeRegisterContext::%s " PRIu32 " retval %" PRIu64,
126                 __FUNCTION__, retval);
127 
128   return retval;
129 }
130 
131 lldb::addr_t
132 NativeRegisterContext::GetPCfromBreakpointLocation(lldb::addr_t fail_value) {
133   return GetPC(fail_value);
134 }
135 
136 Status NativeRegisterContext::SetPC(lldb::addr_t pc) {
137   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
138                                                      LLDB_REGNUM_GENERIC_PC);
139   return WriteRegisterFromUnsigned(reg, pc);
140 }
141 
142 lldb::addr_t NativeRegisterContext::GetSP(lldb::addr_t fail_value) {
143   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
144                                                      LLDB_REGNUM_GENERIC_SP);
145   return ReadRegisterAsUnsigned(reg, fail_value);
146 }
147 
148 Status NativeRegisterContext::SetSP(lldb::addr_t sp) {
149   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
150                                                      LLDB_REGNUM_GENERIC_SP);
151   return WriteRegisterFromUnsigned(reg, sp);
152 }
153 
154 lldb::addr_t NativeRegisterContext::GetFP(lldb::addr_t fail_value) {
155   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
156                                                      LLDB_REGNUM_GENERIC_FP);
157   return ReadRegisterAsUnsigned(reg, fail_value);
158 }
159 
160 Status NativeRegisterContext::SetFP(lldb::addr_t fp) {
161   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
162                                                      LLDB_REGNUM_GENERIC_FP);
163   return WriteRegisterFromUnsigned(reg, fp);
164 }
165 
166 lldb::addr_t NativeRegisterContext::GetReturnAddress(lldb::addr_t fail_value) {
167   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
168                                                      LLDB_REGNUM_GENERIC_RA);
169   return ReadRegisterAsUnsigned(reg, fail_value);
170 }
171 
172 lldb::addr_t NativeRegisterContext::GetFlags(lldb::addr_t fail_value) {
173   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
174                                                      LLDB_REGNUM_GENERIC_FLAGS);
175   return ReadRegisterAsUnsigned(reg, fail_value);
176 }
177 
178 lldb::addr_t
179 NativeRegisterContext::ReadRegisterAsUnsigned(uint32_t reg,
180                                               lldb::addr_t fail_value) {
181   if (reg != LLDB_INVALID_REGNUM)
182     return ReadRegisterAsUnsigned(GetRegisterInfoAtIndex(reg), fail_value);
183   return fail_value;
184 }
185 
186 uint64_t
187 NativeRegisterContext::ReadRegisterAsUnsigned(const RegisterInfo *reg_info,
188                                               lldb::addr_t fail_value) {
189   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
190 
191   if (reg_info) {
192     RegisterValue value;
193     Status error = ReadRegister(reg_info, value);
194     if (error.Success()) {
195       if (log)
196         log->Printf("NativeRegisterContext::%s ReadRegister() succeeded, value "
197                     "%" PRIu64,
198                     __FUNCTION__, value.GetAsUInt64());
199       return value.GetAsUInt64();
200     } else {
201       if (log)
202         log->Printf("NativeRegisterContext::%s ReadRegister() failed, error %s",
203                     __FUNCTION__, error.AsCString());
204     }
205   } else {
206     if (log)
207       log->Printf("NativeRegisterContext::%s ReadRegister() null reg_info",
208                   __FUNCTION__);
209   }
210   return fail_value;
211 }
212 
213 Status NativeRegisterContext::WriteRegisterFromUnsigned(uint32_t reg,
214                                                         uint64_t uval) {
215   if (reg == LLDB_INVALID_REGNUM)
216     return Status("NativeRegisterContext::%s (): reg is invalid", __FUNCTION__);
217   return WriteRegisterFromUnsigned(GetRegisterInfoAtIndex(reg), uval);
218 }
219 
220 Status
221 NativeRegisterContext::WriteRegisterFromUnsigned(const RegisterInfo *reg_info,
222                                                  uint64_t uval) {
223   assert(reg_info);
224   if (!reg_info)
225     return Status("reg_info is nullptr");
226 
227   RegisterValue value;
228   if (!value.SetUInt(uval, reg_info->byte_size))
229     return Status("RegisterValue::SetUInt () failed");
230 
231   return WriteRegister(reg_info, value);
232 }
233 
234 lldb::tid_t NativeRegisterContext::GetThreadID() const {
235   return m_thread.GetID();
236 }
237 
238 uint32_t NativeRegisterContext::NumSupportedHardwareBreakpoints() { return 0; }
239 
240 uint32_t NativeRegisterContext::SetHardwareBreakpoint(lldb::addr_t addr,
241                                                       size_t size) {
242   return LLDB_INVALID_INDEX32;
243 }
244 
245 Status NativeRegisterContext::ClearAllHardwareBreakpoints() {
246   return Status("not implemented");
247 }
248 
249 bool NativeRegisterContext::ClearHardwareBreakpoint(uint32_t hw_idx) {
250   return false;
251 }
252 
253 Status NativeRegisterContext::GetHardwareBreakHitIndex(uint32_t &bp_index,
254                                                        lldb::addr_t trap_addr) {
255   bp_index = LLDB_INVALID_INDEX32;
256   return Status("not implemented");
257 }
258 
259 uint32_t NativeRegisterContext::NumSupportedHardwareWatchpoints() { return 0; }
260 
261 uint32_t NativeRegisterContext::SetHardwareWatchpoint(lldb::addr_t addr,
262                                                       size_t size,
263                                                       uint32_t watch_flags) {
264   return LLDB_INVALID_INDEX32;
265 }
266 
267 bool NativeRegisterContext::ClearHardwareWatchpoint(uint32_t hw_index) {
268   return false;
269 }
270 
271 Status NativeRegisterContext::ClearAllHardwareWatchpoints() {
272   return Status("not implemented");
273 }
274 
275 Status NativeRegisterContext::IsWatchpointHit(uint32_t wp_index, bool &is_hit) {
276   is_hit = false;
277   return Status("not implemented");
278 }
279 
280 Status NativeRegisterContext::GetWatchpointHitIndex(uint32_t &wp_index,
281                                                     lldb::addr_t trap_addr) {
282   wp_index = LLDB_INVALID_INDEX32;
283   return Status("not implemented");
284 }
285 
286 Status NativeRegisterContext::IsWatchpointVacant(uint32_t wp_index,
287                                                  bool &is_vacant) {
288   is_vacant = false;
289   return Status("not implemented");
290 }
291 
292 lldb::addr_t NativeRegisterContext::GetWatchpointAddress(uint32_t wp_index) {
293   return LLDB_INVALID_ADDRESS;
294 }
295 
296 lldb::addr_t NativeRegisterContext::GetWatchpointHitAddress(uint32_t wp_index) {
297   return LLDB_INVALID_ADDRESS;
298 }
299 
300 bool NativeRegisterContext::HardwareSingleStep(bool enable) { return false; }
301 
302 Status NativeRegisterContext::ReadRegisterValueFromMemory(
303     const RegisterInfo *reg_info, lldb::addr_t src_addr, size_t src_len,
304     RegisterValue &reg_value) {
305   Status error;
306   if (reg_info == nullptr) {
307     error.SetErrorString("invalid register info argument.");
308     return error;
309   }
310 
311   // Moving from addr into a register
312   //
313   // Case 1: src_len == dst_len
314   //
315   //   |AABBCCDD| Address contents
316   //   |AABBCCDD| Register contents
317   //
318   // Case 2: src_len > dst_len
319   //
320   //   Status!  (The register should always be big enough to hold the data)
321   //
322   // Case 3: src_len < dst_len
323   //
324   //   |AABB| Address contents
325   //   |AABB0000| Register contents [on little-endian hardware]
326   //   |0000AABB| Register contents [on big-endian hardware]
327   if (src_len > RegisterValue::kMaxRegisterByteSize) {
328     error.SetErrorString("register too small to receive memory data");
329     return error;
330   }
331 
332   const size_t dst_len = reg_info->byte_size;
333 
334   if (src_len > dst_len) {
335     error.SetErrorStringWithFormat(
336         "%" PRIu64 " bytes is too big to store in register %s (%" PRIu64
337         " bytes)",
338         static_cast<uint64_t>(src_len), reg_info->name,
339         static_cast<uint64_t>(dst_len));
340     return error;
341   }
342 
343   NativeProcessProtocol &process = m_thread.GetProcess();
344   uint8_t src[RegisterValue::kMaxRegisterByteSize];
345 
346   // Read the memory
347   size_t bytes_read;
348   error = process.ReadMemory(src_addr, src, src_len, bytes_read);
349   if (error.Fail())
350     return error;
351 
352   // Make sure the memory read succeeded...
353   if (bytes_read != src_len) {
354     // This might happen if we read _some_ bytes but not all
355     error.SetErrorStringWithFormat("read %" PRIu64 " of %" PRIu64 " bytes",
356                                    static_cast<uint64_t>(bytes_read),
357                                    static_cast<uint64_t>(src_len));
358     return error;
359   }
360 
361   // We now have a memory buffer that contains the part or all of the register
362   // value. Set the register value using this memory data.
363   // TODO: we might need to add a parameter to this function in case the byte
364   // order of the memory data doesn't match the process. For now we are
365   // assuming they are the same.
366   reg_value.SetFromMemoryData(reg_info, src, src_len, process.GetByteOrder(),
367                               error);
368 
369   return error;
370 }
371 
372 Status NativeRegisterContext::WriteRegisterValueToMemory(
373     const RegisterInfo *reg_info, lldb::addr_t dst_addr, size_t dst_len,
374     const RegisterValue &reg_value) {
375 
376   uint8_t dst[RegisterValue::kMaxRegisterByteSize];
377 
378   Status error;
379 
380   NativeProcessProtocol &process = m_thread.GetProcess();
381 
382   // TODO: we might need to add a parameter to this function in case the byte
383   // order of the memory data doesn't match the process. For now we are
384   // assuming they are the same.
385   const size_t bytes_copied = reg_value.GetAsMemoryData(
386       reg_info, dst, dst_len, process.GetByteOrder(), error);
387 
388   if (error.Success()) {
389     if (bytes_copied == 0) {
390       error.SetErrorString("byte copy failed.");
391     } else {
392       size_t bytes_written;
393       error = process.WriteMemory(dst_addr, dst, bytes_copied, bytes_written);
394       if (error.Fail())
395         return error;
396 
397       if (bytes_written != bytes_copied) {
398         // This might happen if we read _some_ bytes but not all
399         error.SetErrorStringWithFormat("only wrote %" PRIu64 " of %" PRIu64
400                                        " bytes",
401                                        static_cast<uint64_t>(bytes_written),
402                                        static_cast<uint64_t>(bytes_copied));
403       }
404     }
405   }
406 
407   return error;
408 }
409 
410 uint32_t
411 NativeRegisterContext::ConvertRegisterKindToRegisterNumber(uint32_t kind,
412                                                            uint32_t num) const {
413   const uint32_t num_regs = GetRegisterCount();
414 
415   assert(kind < kNumRegisterKinds);
416   for (uint32_t reg_idx = 0; reg_idx < num_regs; ++reg_idx) {
417     const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg_idx);
418 
419     if (reg_info->kinds[kind] == num)
420       return reg_idx;
421   }
422 
423   return LLDB_INVALID_REGNUM;
424 }
425