1 //===-- NativeRegisterContext.cpp -----------------------------------------===//
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   LLDB_LOGF(log,
118             "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   LLDB_LOGF(log, "NativeRegisterContext::%s " PRIu32 " retval %" PRIu64,
125             __FUNCTION__, retval);
126 
127   return retval;
128 }
129 
130 lldb::addr_t
131 NativeRegisterContext::GetPCfromBreakpointLocation(lldb::addr_t fail_value) {
132   return GetPC(fail_value);
133 }
134 
135 Status NativeRegisterContext::SetPC(lldb::addr_t pc) {
136   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
137                                                      LLDB_REGNUM_GENERIC_PC);
138   return WriteRegisterFromUnsigned(reg, pc);
139 }
140 
141 lldb::addr_t NativeRegisterContext::GetSP(lldb::addr_t fail_value) {
142   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
143                                                      LLDB_REGNUM_GENERIC_SP);
144   return ReadRegisterAsUnsigned(reg, fail_value);
145 }
146 
147 Status NativeRegisterContext::SetSP(lldb::addr_t sp) {
148   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
149                                                      LLDB_REGNUM_GENERIC_SP);
150   return WriteRegisterFromUnsigned(reg, sp);
151 }
152 
153 lldb::addr_t NativeRegisterContext::GetFP(lldb::addr_t fail_value) {
154   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
155                                                      LLDB_REGNUM_GENERIC_FP);
156   return ReadRegisterAsUnsigned(reg, fail_value);
157 }
158 
159 Status NativeRegisterContext::SetFP(lldb::addr_t fp) {
160   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
161                                                      LLDB_REGNUM_GENERIC_FP);
162   return WriteRegisterFromUnsigned(reg, fp);
163 }
164 
165 lldb::addr_t NativeRegisterContext::GetReturnAddress(lldb::addr_t fail_value) {
166   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
167                                                      LLDB_REGNUM_GENERIC_RA);
168   return ReadRegisterAsUnsigned(reg, fail_value);
169 }
170 
171 lldb::addr_t NativeRegisterContext::GetFlags(lldb::addr_t fail_value) {
172   uint32_t reg = ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric,
173                                                      LLDB_REGNUM_GENERIC_FLAGS);
174   return ReadRegisterAsUnsigned(reg, fail_value);
175 }
176 
177 lldb::addr_t
178 NativeRegisterContext::ReadRegisterAsUnsigned(uint32_t reg,
179                                               lldb::addr_t fail_value) {
180   if (reg != LLDB_INVALID_REGNUM)
181     return ReadRegisterAsUnsigned(GetRegisterInfoAtIndex(reg), fail_value);
182   return fail_value;
183 }
184 
185 uint64_t
186 NativeRegisterContext::ReadRegisterAsUnsigned(const RegisterInfo *reg_info,
187                                               lldb::addr_t fail_value) {
188   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
189 
190   if (reg_info) {
191     RegisterValue value;
192     Status error = ReadRegister(reg_info, value);
193     if (error.Success()) {
194       LLDB_LOGF(log,
195                 "NativeRegisterContext::%s ReadRegister() succeeded, value "
196                 "%" PRIu64,
197                 __FUNCTION__, value.GetAsUInt64());
198       return value.GetAsUInt64();
199     } else {
200       LLDB_LOGF(log,
201                 "NativeRegisterContext::%s ReadRegister() failed, error %s",
202                 __FUNCTION__, error.AsCString());
203     }
204   } else {
205     LLDB_LOGF(log, "NativeRegisterContext::%s ReadRegister() null reg_info",
206               __FUNCTION__);
207   }
208   return fail_value;
209 }
210 
211 Status NativeRegisterContext::WriteRegisterFromUnsigned(uint32_t reg,
212                                                         uint64_t uval) {
213   if (reg == LLDB_INVALID_REGNUM)
214     return Status("NativeRegisterContext::%s (): reg is invalid", __FUNCTION__);
215   return WriteRegisterFromUnsigned(GetRegisterInfoAtIndex(reg), uval);
216 }
217 
218 Status
219 NativeRegisterContext::WriteRegisterFromUnsigned(const RegisterInfo *reg_info,
220                                                  uint64_t uval) {
221   assert(reg_info);
222   if (!reg_info)
223     return Status("reg_info is nullptr");
224 
225   RegisterValue value;
226   if (!value.SetUInt(uval, reg_info->byte_size))
227     return Status("RegisterValue::SetUInt () failed");
228 
229   return WriteRegister(reg_info, value);
230 }
231 
232 lldb::tid_t NativeRegisterContext::GetThreadID() const {
233   return m_thread.GetID();
234 }
235 
236 uint32_t NativeRegisterContext::NumSupportedHardwareBreakpoints() { return 0; }
237 
238 uint32_t NativeRegisterContext::SetHardwareBreakpoint(lldb::addr_t addr,
239                                                       size_t size) {
240   return LLDB_INVALID_INDEX32;
241 }
242 
243 Status NativeRegisterContext::ClearAllHardwareBreakpoints() {
244   return Status("not implemented");
245 }
246 
247 bool NativeRegisterContext::ClearHardwareBreakpoint(uint32_t hw_idx) {
248   return false;
249 }
250 
251 Status NativeRegisterContext::GetHardwareBreakHitIndex(uint32_t &bp_index,
252                                                        lldb::addr_t trap_addr) {
253   bp_index = LLDB_INVALID_INDEX32;
254   return Status("not implemented");
255 }
256 
257 uint32_t NativeRegisterContext::NumSupportedHardwareWatchpoints() { return 0; }
258 
259 uint32_t NativeRegisterContext::SetHardwareWatchpoint(lldb::addr_t addr,
260                                                       size_t size,
261                                                       uint32_t watch_flags) {
262   return LLDB_INVALID_INDEX32;
263 }
264 
265 bool NativeRegisterContext::ClearHardwareWatchpoint(uint32_t hw_index) {
266   return false;
267 }
268 
269 Status NativeRegisterContext::ClearWatchpointHit(uint32_t hw_index) {
270   return Status("not implemented");
271 }
272 
273 Status NativeRegisterContext::ClearAllHardwareWatchpoints() {
274   return Status("not implemented");
275 }
276 
277 Status NativeRegisterContext::IsWatchpointHit(uint32_t wp_index, bool &is_hit) {
278   is_hit = false;
279   return Status("not implemented");
280 }
281 
282 Status NativeRegisterContext::GetWatchpointHitIndex(uint32_t &wp_index,
283                                                     lldb::addr_t trap_addr) {
284   wp_index = LLDB_INVALID_INDEX32;
285   return Status("not implemented");
286 }
287 
288 Status NativeRegisterContext::IsWatchpointVacant(uint32_t wp_index,
289                                                  bool &is_vacant) {
290   is_vacant = false;
291   return Status("not implemented");
292 }
293 
294 lldb::addr_t NativeRegisterContext::GetWatchpointAddress(uint32_t wp_index) {
295   return LLDB_INVALID_ADDRESS;
296 }
297 
298 lldb::addr_t NativeRegisterContext::GetWatchpointHitAddress(uint32_t wp_index) {
299   return LLDB_INVALID_ADDRESS;
300 }
301 
302 bool NativeRegisterContext::HardwareSingleStep(bool enable) { return false; }
303 
304 Status NativeRegisterContext::ReadRegisterValueFromMemory(
305     const RegisterInfo *reg_info, lldb::addr_t src_addr, size_t src_len,
306     RegisterValue &reg_value) {
307   Status error;
308   if (reg_info == nullptr) {
309     error.SetErrorString("invalid register info argument.");
310     return error;
311   }
312 
313   // Moving from addr into a register
314   //
315   // Case 1: src_len == dst_len
316   //
317   //   |AABBCCDD| Address contents
318   //   |AABBCCDD| Register contents
319   //
320   // Case 2: src_len > dst_len
321   //
322   //   Status!  (The register should always be big enough to hold the data)
323   //
324   // Case 3: src_len < dst_len
325   //
326   //   |AABB| Address contents
327   //   |AABB0000| Register contents [on little-endian hardware]
328   //   |0000AABB| Register contents [on big-endian hardware]
329   if (src_len > RegisterValue::kMaxRegisterByteSize) {
330     error.SetErrorString("register too small to receive memory data");
331     return error;
332   }
333 
334   const size_t dst_len = reg_info->byte_size;
335 
336   if (src_len > dst_len) {
337     error.SetErrorStringWithFormat(
338         "%" PRIu64 " bytes is too big to store in register %s (%" PRIu64
339         " bytes)",
340         static_cast<uint64_t>(src_len), reg_info->name,
341         static_cast<uint64_t>(dst_len));
342     return error;
343   }
344 
345   NativeProcessProtocol &process = m_thread.GetProcess();
346   uint8_t src[RegisterValue::kMaxRegisterByteSize];
347 
348   // Read the memory
349   size_t bytes_read;
350   error = process.ReadMemory(src_addr, src, src_len, bytes_read);
351   if (error.Fail())
352     return error;
353 
354   // Make sure the memory read succeeded...
355   if (bytes_read != src_len) {
356     // This might happen if we read _some_ bytes but not all
357     error.SetErrorStringWithFormat("read %" PRIu64 " of %" PRIu64 " bytes",
358                                    static_cast<uint64_t>(bytes_read),
359                                    static_cast<uint64_t>(src_len));
360     return error;
361   }
362 
363   // We now have a memory buffer that contains the part or all of the register
364   // value. Set the register value using this memory data.
365   // TODO: we might need to add a parameter to this function in case the byte
366   // order of the memory data doesn't match the process. For now we are
367   // assuming they are the same.
368   reg_value.SetFromMemoryData(reg_info, src, src_len, process.GetByteOrder(),
369                               error);
370 
371   return error;
372 }
373 
374 Status NativeRegisterContext::WriteRegisterValueToMemory(
375     const RegisterInfo *reg_info, lldb::addr_t dst_addr, size_t dst_len,
376     const RegisterValue &reg_value) {
377 
378   uint8_t dst[RegisterValue::kMaxRegisterByteSize];
379 
380   Status error;
381 
382   NativeProcessProtocol &process = m_thread.GetProcess();
383 
384   // TODO: we might need to add a parameter to this function in case the byte
385   // order of the memory data doesn't match the process. For now we are
386   // assuming they are the same.
387   const size_t bytes_copied = reg_value.GetAsMemoryData(
388       reg_info, dst, dst_len, process.GetByteOrder(), error);
389 
390   if (error.Success()) {
391     if (bytes_copied == 0) {
392       error.SetErrorString("byte copy failed.");
393     } else {
394       size_t bytes_written;
395       error = process.WriteMemory(dst_addr, dst, bytes_copied, bytes_written);
396       if (error.Fail())
397         return error;
398 
399       if (bytes_written != bytes_copied) {
400         // This might happen if we read _some_ bytes but not all
401         error.SetErrorStringWithFormat("only wrote %" PRIu64 " of %" PRIu64
402                                        " bytes",
403                                        static_cast<uint64_t>(bytes_written),
404                                        static_cast<uint64_t>(bytes_copied));
405       }
406     }
407   }
408 
409   return error;
410 }
411 
412 uint32_t
413 NativeRegisterContext::ConvertRegisterKindToRegisterNumber(uint32_t kind,
414                                                            uint32_t num) const {
415   const uint32_t num_regs = GetRegisterCount();
416 
417   assert(kind < kNumRegisterKinds);
418   for (uint32_t reg_idx = 0; reg_idx < num_regs; ++reg_idx) {
419     const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg_idx);
420 
421     if (reg_info->kinds[kind] == num)
422       return reg_idx;
423   }
424 
425   return LLDB_INVALID_REGNUM;
426 }
427 
428 std::vector<uint32_t>
429 NativeRegisterContext::GetExpeditedRegisters(ExpeditedRegs expType) const {
430   if (expType == ExpeditedRegs::Minimal) {
431     // Expedite only a minimum set of important generic registers.
432     static const uint32_t k_expedited_registers[] = {
433         LLDB_REGNUM_GENERIC_PC, LLDB_REGNUM_GENERIC_SP, LLDB_REGNUM_GENERIC_FP,
434         LLDB_REGNUM_GENERIC_RA};
435 
436     std::vector<uint32_t> expedited_reg_nums;
437     for (uint32_t gen_reg : k_expedited_registers) {
438       uint32_t reg_num =
439           ConvertRegisterKindToRegisterNumber(eRegisterKindGeneric, gen_reg);
440       if (reg_num == LLDB_INVALID_REGNUM)
441         continue; // Target does not support the given register.
442       else
443         expedited_reg_nums.push_back(reg_num);
444     }
445 
446     return expedited_reg_nums;
447   }
448 
449   if (GetRegisterSetCount() > 0 && expType == ExpeditedRegs::Full)
450     return std::vector<uint32_t>(GetRegisterSet(0)->registers,
451                                  GetRegisterSet(0)->registers +
452                                      GetRegisterSet(0)->num_registers);
453 
454   return std::vector<uint32_t>();
455 }
456