1 //===-- GDBRemoteRegisterContext.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 "GDBRemoteRegisterContext.h"
10 
11 #include "ProcessGDBRemote.h"
12 #include "ProcessGDBRemoteLog.h"
13 #include "ThreadGDBRemote.h"
14 #include "Utility/ARM_DWARF_Registers.h"
15 #include "Utility/ARM_ehframe_Registers.h"
16 #include "lldb/Core/Architecture.h"
17 #include "lldb/Target/ExecutionContext.h"
18 #include "lldb/Target/Target.h"
19 #include "lldb/Utility/DataBufferHeap.h"
20 #include "lldb/Utility/DataExtractor.h"
21 #include "lldb/Utility/RegisterValue.h"
22 #include "lldb/Utility/Scalar.h"
23 #include "lldb/Utility/StreamString.h"
24 #include "lldb/Utility/StringExtractorGDBRemote.h"
25 
26 #include <memory>
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 using namespace lldb_private::process_gdb_remote;
31 
32 // GDBRemoteRegisterContext constructor
GDBRemoteRegisterContext(ThreadGDBRemote & thread,uint32_t concrete_frame_idx,GDBRemoteDynamicRegisterInfoSP reg_info_sp,bool read_all_at_once,bool write_all_at_once)33 GDBRemoteRegisterContext::GDBRemoteRegisterContext(
34     ThreadGDBRemote &thread, uint32_t concrete_frame_idx,
35     GDBRemoteDynamicRegisterInfoSP reg_info_sp, bool read_all_at_once,
36     bool write_all_at_once)
37     : RegisterContext(thread, concrete_frame_idx),
38       m_reg_info_sp(std::move(reg_info_sp)), m_reg_valid(), m_reg_data(),
39       m_read_all_at_once(read_all_at_once),
40       m_write_all_at_once(write_all_at_once), m_gpacket_cached(false) {
41   // Resize our vector of bools to contain one bool for every register. We will
42   // use these boolean values to know when a register value is valid in
43   // m_reg_data.
44   m_reg_valid.resize(m_reg_info_sp->GetNumRegisters());
45 
46   // Make a heap based buffer that is big enough to store all registers
47   DataBufferSP reg_data_sp(
48       new DataBufferHeap(m_reg_info_sp->GetRegisterDataByteSize(), 0));
49   m_reg_data.SetData(reg_data_sp);
50   m_reg_data.SetByteOrder(thread.GetProcess()->GetByteOrder());
51 }
52 
53 // Destructor
54 GDBRemoteRegisterContext::~GDBRemoteRegisterContext() = default;
55 
InvalidateAllRegisters()56 void GDBRemoteRegisterContext::InvalidateAllRegisters() {
57   SetAllRegisterValid(false);
58 }
59 
SetAllRegisterValid(bool b)60 void GDBRemoteRegisterContext::SetAllRegisterValid(bool b) {
61   m_gpacket_cached = b;
62   std::vector<bool>::iterator pos, end = m_reg_valid.end();
63   for (pos = m_reg_valid.begin(); pos != end; ++pos)
64     *pos = b;
65 }
66 
GetRegisterCount()67 size_t GDBRemoteRegisterContext::GetRegisterCount() {
68   return m_reg_info_sp->GetNumRegisters();
69 }
70 
71 const RegisterInfo *
GetRegisterInfoAtIndex(size_t reg)72 GDBRemoteRegisterContext::GetRegisterInfoAtIndex(size_t reg) {
73   return m_reg_info_sp->GetRegisterInfoAtIndex(reg);
74 }
75 
GetRegisterSetCount()76 size_t GDBRemoteRegisterContext::GetRegisterSetCount() {
77   return m_reg_info_sp->GetNumRegisterSets();
78 }
79 
GetRegisterSet(size_t reg_set)80 const RegisterSet *GDBRemoteRegisterContext::GetRegisterSet(size_t reg_set) {
81   return m_reg_info_sp->GetRegisterSet(reg_set);
82 }
83 
ReadRegister(const RegisterInfo * reg_info,RegisterValue & value)84 bool GDBRemoteRegisterContext::ReadRegister(const RegisterInfo *reg_info,
85                                             RegisterValue &value) {
86   // Read the register
87   if (ReadRegisterBytes(reg_info)) {
88     const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
89     if (m_reg_valid[reg] == false)
90       return false;
91     if (reg_info->value_regs &&
92         reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
93         reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
94       std::vector<char> combined_data;
95       uint32_t offset = 0;
96       for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
97         const RegisterInfo *parent_reg = GetRegisterInfo(
98             eRegisterKindLLDB, reg_info->value_regs[i]);
99         if (!parent_reg)
100           return false;
101         combined_data.resize(offset + parent_reg->byte_size);
102         if (m_reg_data.CopyData(parent_reg->byte_offset, parent_reg->byte_size,
103                                 combined_data.data() + offset) !=
104             parent_reg->byte_size)
105           return false;
106         offset += parent_reg->byte_size;
107       }
108 
109       Status error;
110       return value.SetFromMemoryData(
111                  *reg_info, combined_data.data(), combined_data.size(),
112                  m_reg_data.GetByteOrder(), error) == combined_data.size();
113     } else {
114       const bool partial_data_ok = false;
115       Status error(value.SetValueFromData(
116           *reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
117       return error.Success();
118     }
119   }
120   return false;
121 }
122 
PrivateSetRegisterValue(uint32_t reg,llvm::ArrayRef<uint8_t> data)123 bool GDBRemoteRegisterContext::PrivateSetRegisterValue(
124     uint32_t reg, llvm::ArrayRef<uint8_t> data) {
125   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
126   if (reg_info == nullptr)
127     return false;
128 
129   // Invalidate if needed
130   InvalidateIfNeeded(false);
131 
132   const size_t reg_byte_size = reg_info->byte_size;
133   memcpy(const_cast<uint8_t *>(
134              m_reg_data.PeekData(reg_info->byte_offset, reg_byte_size)),
135          data.data(), std::min(data.size(), reg_byte_size));
136   bool success = data.size() >= reg_byte_size;
137   if (success) {
138     SetRegisterIsValid(reg, true);
139   } else if (data.size() > 0) {
140     // Only set register is valid to false if we copied some bytes, else leave
141     // it as it was.
142     SetRegisterIsValid(reg, false);
143   }
144   return success;
145 }
146 
PrivateSetRegisterValue(uint32_t reg,uint64_t new_reg_val)147 bool GDBRemoteRegisterContext::PrivateSetRegisterValue(uint32_t reg,
148                                                        uint64_t new_reg_val) {
149   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
150   if (reg_info == nullptr)
151     return false;
152 
153   // Early in process startup, we can get a thread that has an invalid byte
154   // order because the process hasn't been completely set up yet (see the ctor
155   // where the byte order is setfrom the process).  If that's the case, we
156   // can't set the value here.
157   if (m_reg_data.GetByteOrder() == eByteOrderInvalid) {
158     return false;
159   }
160 
161   // Invalidate if needed
162   InvalidateIfNeeded(false);
163 
164   DataBufferSP buffer_sp(new DataBufferHeap(&new_reg_val, sizeof(new_reg_val)));
165   DataExtractor data(buffer_sp, endian::InlHostByteOrder(), sizeof(void *));
166 
167   // If our register context and our register info disagree, which should never
168   // happen, don't overwrite past the end of the buffer.
169   if (m_reg_data.GetByteSize() < reg_info->byte_offset + reg_info->byte_size)
170     return false;
171 
172   // Grab a pointer to where we are going to put this register
173   uint8_t *dst = const_cast<uint8_t *>(
174       m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
175 
176   if (dst == nullptr)
177     return false;
178 
179   if (data.CopyByteOrderedData(0,                          // src offset
180                                reg_info->byte_size,        // src length
181                                dst,                        // dst
182                                reg_info->byte_size,        // dst length
183                                m_reg_data.GetByteOrder())) // dst byte order
184   {
185     SetRegisterIsValid(reg, true);
186     return true;
187   }
188   return false;
189 }
190 
191 // Helper function for GDBRemoteRegisterContext::ReadRegisterBytes().
GetPrimordialRegister(const RegisterInfo * reg_info,GDBRemoteCommunicationClient & gdb_comm)192 bool GDBRemoteRegisterContext::GetPrimordialRegister(
193     const RegisterInfo *reg_info, GDBRemoteCommunicationClient &gdb_comm) {
194   const uint32_t lldb_reg = reg_info->kinds[eRegisterKindLLDB];
195   const uint32_t remote_reg = reg_info->kinds[eRegisterKindProcessPlugin];
196 
197   if (DataBufferSP buffer_sp =
198           gdb_comm.ReadRegister(m_thread.GetProtocolID(), remote_reg))
199     return PrivateSetRegisterValue(
200         lldb_reg, llvm::ArrayRef<uint8_t>(buffer_sp->GetBytes(),
201                                           buffer_sp->GetByteSize()));
202   return false;
203 }
204 
ReadRegisterBytes(const RegisterInfo * reg_info)205 bool GDBRemoteRegisterContext::ReadRegisterBytes(const RegisterInfo *reg_info) {
206   ExecutionContext exe_ctx(CalculateThread());
207 
208   Process *process = exe_ctx.GetProcessPtr();
209   Thread *thread = exe_ctx.GetThreadPtr();
210   if (process == nullptr || thread == nullptr)
211     return false;
212 
213   GDBRemoteCommunicationClient &gdb_comm(
214       ((ProcessGDBRemote *)process)->GetGDBRemote());
215 
216   InvalidateIfNeeded(false);
217 
218   const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
219 
220   if (!GetRegisterIsValid(reg)) {
221     if (m_read_all_at_once && !m_gpacket_cached) {
222       if (DataBufferSP buffer_sp =
223               gdb_comm.ReadAllRegisters(m_thread.GetProtocolID())) {
224         memcpy(const_cast<uint8_t *>(m_reg_data.GetDataStart()),
225                buffer_sp->GetBytes(),
226                std::min(buffer_sp->GetByteSize(), m_reg_data.GetByteSize()));
227         if (buffer_sp->GetByteSize() >= m_reg_data.GetByteSize()) {
228           SetAllRegisterValid(true);
229           return true;
230         } else if (buffer_sp->GetByteSize() > 0) {
231           for (auto x : llvm::enumerate(
232                    m_reg_info_sp->registers<
233                        DynamicRegisterInfo::reg_collection_const_range>())) {
234             const struct RegisterInfo &reginfo = x.value();
235             m_reg_valid[x.index()] =
236                 (reginfo.byte_offset + reginfo.byte_size <=
237                  buffer_sp->GetByteSize());
238           }
239 
240           m_gpacket_cached = true;
241           if (GetRegisterIsValid(reg))
242             return true;
243         } else {
244           Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
245           LLDB_LOGF(
246               log,
247               "error: GDBRemoteRegisterContext::ReadRegisterBytes tried "
248               "to read the "
249               "entire register context at once, expected at least %" PRId64
250               " bytes "
251               "but only got %" PRId64 " bytes.",
252               m_reg_data.GetByteSize(), buffer_sp->GetByteSize());
253           return false;
254         }
255       }
256     }
257     if (reg_info->value_regs) {
258       // Process this composite register request by delegating to the
259       // constituent primordial registers.
260 
261       // Index of the primordial register.
262       bool success = true;
263       for (uint32_t idx = 0; success; ++idx) {
264         const uint32_t prim_reg = reg_info->value_regs[idx];
265         if (prim_reg == LLDB_INVALID_REGNUM)
266           break;
267         // We have a valid primordial register as our constituent. Grab the
268         // corresponding register info.
269         const RegisterInfo *prim_reg_info =
270             GetRegisterInfo(eRegisterKindLLDB, prim_reg);
271         if (prim_reg_info == nullptr)
272           success = false;
273         else {
274           // Read the containing register if it hasn't already been read
275           if (!GetRegisterIsValid(prim_reg))
276             success = GetPrimordialRegister(prim_reg_info, gdb_comm);
277         }
278       }
279 
280       if (success) {
281         // If we reach this point, all primordial register requests have
282         // succeeded. Validate this composite register.
283         SetRegisterIsValid(reg_info, true);
284       }
285     } else {
286       // Get each register individually
287       GetPrimordialRegister(reg_info, gdb_comm);
288     }
289 
290     // Make sure we got a valid register value after reading it
291     if (!GetRegisterIsValid(reg))
292       return false;
293   }
294 
295   return true;
296 }
297 
WriteRegister(const RegisterInfo * reg_info,const RegisterValue & value)298 bool GDBRemoteRegisterContext::WriteRegister(const RegisterInfo *reg_info,
299                                              const RegisterValue &value) {
300   DataExtractor data;
301   if (value.GetData(data)) {
302     if (reg_info->value_regs &&
303         reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
304         reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
305       uint32_t combined_size = 0;
306       for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
307         const RegisterInfo *parent_reg = GetRegisterInfo(
308             eRegisterKindLLDB, reg_info->value_regs[i]);
309         if (!parent_reg)
310           return false;
311         combined_size += parent_reg->byte_size;
312       }
313 
314       if (data.GetByteSize() < combined_size)
315         return false;
316 
317       uint32_t offset = 0;
318       for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
319         const RegisterInfo *parent_reg = GetRegisterInfo(
320             eRegisterKindLLDB, reg_info->value_regs[i]);
321         assert(parent_reg);
322 
323         DataExtractor parent_data{data, offset, parent_reg->byte_size};
324         if (!WriteRegisterBytes(parent_reg, parent_data, 0))
325           return false;
326         offset += parent_reg->byte_size;
327       }
328       assert(offset == combined_size);
329       return true;
330     } else
331       return WriteRegisterBytes(reg_info, data, 0);
332   }
333   return false;
334 }
335 
336 // Helper function for GDBRemoteRegisterContext::WriteRegisterBytes().
SetPrimordialRegister(const RegisterInfo * reg_info,GDBRemoteCommunicationClient & gdb_comm)337 bool GDBRemoteRegisterContext::SetPrimordialRegister(
338     const RegisterInfo *reg_info, GDBRemoteCommunicationClient &gdb_comm) {
339   StreamString packet;
340   StringExtractorGDBRemote response;
341   const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
342   // Invalidate just this register
343   SetRegisterIsValid(reg, false);
344 
345   return gdb_comm.WriteRegister(
346       m_thread.GetProtocolID(), reg_info->kinds[eRegisterKindProcessPlugin],
347       {m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size),
348        reg_info->byte_size});
349 }
350 
WriteRegisterBytes(const RegisterInfo * reg_info,DataExtractor & data,uint32_t data_offset)351 bool GDBRemoteRegisterContext::WriteRegisterBytes(const RegisterInfo *reg_info,
352                                                   DataExtractor &data,
353                                                   uint32_t data_offset) {
354   ExecutionContext exe_ctx(CalculateThread());
355 
356   Process *process = exe_ctx.GetProcessPtr();
357   Thread *thread = exe_ctx.GetThreadPtr();
358   if (process == nullptr || thread == nullptr)
359     return false;
360 
361   GDBRemoteCommunicationClient &gdb_comm(
362       ((ProcessGDBRemote *)process)->GetGDBRemote());
363 
364   assert(m_reg_data.GetByteSize() >=
365          reg_info->byte_offset + reg_info->byte_size);
366 
367   // If our register context and our register info disagree, which should never
368   // happen, don't overwrite past the end of the buffer.
369   if (m_reg_data.GetByteSize() < reg_info->byte_offset + reg_info->byte_size)
370     return false;
371 
372   // Grab a pointer to where we are going to put this register
373   uint8_t *dst = const_cast<uint8_t *>(
374       m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
375 
376   if (dst == nullptr)
377     return false;
378 
379   const bool should_reconfigure_registers =
380       RegisterWriteCausesReconfigure(reg_info->name);
381 
382   if (data.CopyByteOrderedData(data_offset,                // src offset
383                                reg_info->byte_size,        // src length
384                                dst,                        // dst
385                                reg_info->byte_size,        // dst length
386                                m_reg_data.GetByteOrder())) // dst byte order
387   {
388     GDBRemoteClientBase::Lock lock(gdb_comm);
389     if (lock) {
390       if (m_write_all_at_once) {
391         // Invalidate all register values
392         InvalidateIfNeeded(true);
393 
394         // Set all registers in one packet
395         if (gdb_comm.WriteAllRegisters(
396                 m_thread.GetProtocolID(),
397                 {m_reg_data.GetDataStart(), size_t(m_reg_data.GetByteSize())}))
398 
399         {
400           if (should_reconfigure_registers)
401             ReconfigureRegisterInfo();
402 
403           InvalidateAllRegisters();
404 
405           return true;
406         }
407       } else {
408         bool success = true;
409 
410         if (reg_info->value_regs) {
411           // This register is part of another register. In this case we read
412           // the actual register data for any "value_regs", and once all that
413           // data is read, we will have enough data in our register context
414           // bytes for the value of this register
415 
416           // Invalidate this composite register first.
417 
418           for (uint32_t idx = 0; success; ++idx) {
419             const uint32_t reg = reg_info->value_regs[idx];
420             if (reg == LLDB_INVALID_REGNUM)
421               break;
422             // We have a valid primordial register as our constituent. Grab the
423             // corresponding register info.
424             const RegisterInfo *value_reg_info =
425                 GetRegisterInfo(eRegisterKindLLDB, reg);
426             if (value_reg_info == nullptr)
427               success = false;
428             else
429               success = SetPrimordialRegister(value_reg_info, gdb_comm);
430           }
431         } else {
432           // This is an actual register, write it
433           success = SetPrimordialRegister(reg_info, gdb_comm);
434         }
435 
436         // Check if writing this register will invalidate any other register
437         // values? If so, invalidate them
438         if (reg_info->invalidate_regs) {
439           for (uint32_t idx = 0, reg = reg_info->invalidate_regs[0];
440                reg != LLDB_INVALID_REGNUM;
441                reg = reg_info->invalidate_regs[++idx])
442             SetRegisterIsValid(ConvertRegisterKindToRegisterNumber(
443                                    eRegisterKindLLDB, reg),
444                                false);
445         }
446 
447         if (success && should_reconfigure_registers &&
448             ReconfigureRegisterInfo())
449           InvalidateAllRegisters();
450 
451         return success;
452       }
453     } else {
454       Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
455       if (log) {
456         if (log->GetVerbose()) {
457           StreamString strm;
458           process->DumpPluginHistory(strm);
459           LLDB_LOGF(log,
460                     "error: failed to get packet sequence mutex, not sending "
461                     "write register for \"%s\":\n%s",
462                     reg_info->name, strm.GetData());
463         } else
464           LLDB_LOGF(log,
465                     "error: failed to get packet sequence mutex, not sending "
466                     "write register for \"%s\"",
467                     reg_info->name);
468       }
469     }
470   }
471   return false;
472 }
473 
ReadAllRegisterValues(RegisterCheckpoint & reg_checkpoint)474 bool GDBRemoteRegisterContext::ReadAllRegisterValues(
475     RegisterCheckpoint &reg_checkpoint) {
476   ExecutionContext exe_ctx(CalculateThread());
477 
478   Process *process = exe_ctx.GetProcessPtr();
479   Thread *thread = exe_ctx.GetThreadPtr();
480   if (process == nullptr || thread == nullptr)
481     return false;
482 
483   GDBRemoteCommunicationClient &gdb_comm(
484       ((ProcessGDBRemote *)process)->GetGDBRemote());
485 
486   uint32_t save_id = 0;
487   if (gdb_comm.SaveRegisterState(thread->GetProtocolID(), save_id)) {
488     reg_checkpoint.SetID(save_id);
489     reg_checkpoint.GetData().reset();
490     return true;
491   } else {
492     reg_checkpoint.SetID(0); // Invalid save ID is zero
493     return ReadAllRegisterValues(reg_checkpoint.GetData());
494   }
495 }
496 
WriteAllRegisterValues(const RegisterCheckpoint & reg_checkpoint)497 bool GDBRemoteRegisterContext::WriteAllRegisterValues(
498     const RegisterCheckpoint &reg_checkpoint) {
499   uint32_t save_id = reg_checkpoint.GetID();
500   if (save_id != 0) {
501     ExecutionContext exe_ctx(CalculateThread());
502 
503     Process *process = exe_ctx.GetProcessPtr();
504     Thread *thread = exe_ctx.GetThreadPtr();
505     if (process == nullptr || thread == nullptr)
506       return false;
507 
508     GDBRemoteCommunicationClient &gdb_comm(
509         ((ProcessGDBRemote *)process)->GetGDBRemote());
510 
511     return gdb_comm.RestoreRegisterState(m_thread.GetProtocolID(), save_id);
512   } else {
513     return WriteAllRegisterValues(reg_checkpoint.GetData());
514   }
515 }
516 
ReadAllRegisterValues(lldb::WritableDataBufferSP & data_sp)517 bool GDBRemoteRegisterContext::ReadAllRegisterValues(
518     lldb::WritableDataBufferSP &data_sp) {
519   ExecutionContext exe_ctx(CalculateThread());
520 
521   Process *process = exe_ctx.GetProcessPtr();
522   Thread *thread = exe_ctx.GetThreadPtr();
523   if (process == nullptr || thread == nullptr)
524     return false;
525 
526   GDBRemoteCommunicationClient &gdb_comm(
527       ((ProcessGDBRemote *)process)->GetGDBRemote());
528 
529   const bool use_g_packet =
530       !gdb_comm.AvoidGPackets((ProcessGDBRemote *)process);
531 
532   GDBRemoteClientBase::Lock lock(gdb_comm);
533   if (lock) {
534     if (gdb_comm.SyncThreadState(m_thread.GetProtocolID()))
535       InvalidateAllRegisters();
536 
537     if (use_g_packet) {
538       if (DataBufferSP data_buffer =
539               gdb_comm.ReadAllRegisters(m_thread.GetProtocolID())) {
540         data_sp = std::make_shared<DataBufferHeap>(*data_buffer);
541         return true;
542       }
543     }
544 
545     // We're going to read each register
546     // individually and store them as binary data in a buffer.
547     const RegisterInfo *reg_info;
548 
549     for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != nullptr;
550          i++) {
551       if (reg_info
552               ->value_regs) // skip registers that are slices of real registers
553         continue;
554       ReadRegisterBytes(reg_info);
555       // ReadRegisterBytes saves the contents of the register in to the
556       // m_reg_data buffer
557     }
558     data_sp = std::make_shared<DataBufferHeap>(
559         m_reg_data.GetDataStart(), m_reg_info_sp->GetRegisterDataByteSize());
560     return true;
561   } else {
562 
563     Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
564     if (log) {
565       if (log->GetVerbose()) {
566         StreamString strm;
567         process->DumpPluginHistory(strm);
568         LLDB_LOGF(log,
569                   "error: failed to get packet sequence mutex, not sending "
570                   "read all registers:\n%s",
571                   strm.GetData());
572       } else
573         LLDB_LOGF(log,
574                   "error: failed to get packet sequence mutex, not sending "
575                   "read all registers");
576     }
577   }
578 
579   data_sp.reset();
580   return false;
581 }
582 
WriteAllRegisterValues(const lldb::DataBufferSP & data_sp)583 bool GDBRemoteRegisterContext::WriteAllRegisterValues(
584     const lldb::DataBufferSP &data_sp) {
585   if (!data_sp || data_sp->GetBytes() == nullptr || data_sp->GetByteSize() == 0)
586     return false;
587 
588   ExecutionContext exe_ctx(CalculateThread());
589 
590   Process *process = exe_ctx.GetProcessPtr();
591   Thread *thread = exe_ctx.GetThreadPtr();
592   if (process == nullptr || thread == nullptr)
593     return false;
594 
595   GDBRemoteCommunicationClient &gdb_comm(
596       ((ProcessGDBRemote *)process)->GetGDBRemote());
597 
598   const bool use_g_packet =
599       !gdb_comm.AvoidGPackets((ProcessGDBRemote *)process);
600 
601   GDBRemoteClientBase::Lock lock(gdb_comm);
602   if (lock) {
603     // The data_sp contains the G response packet.
604     if (use_g_packet) {
605       if (gdb_comm.WriteAllRegisters(
606               m_thread.GetProtocolID(),
607               {data_sp->GetBytes(), size_t(data_sp->GetByteSize())}))
608         return true;
609 
610       uint32_t num_restored = 0;
611       // We need to manually go through all of the registers and restore them
612       // manually
613       DataExtractor restore_data(data_sp, m_reg_data.GetByteOrder(),
614                                  m_reg_data.GetAddressByteSize());
615 
616       const RegisterInfo *reg_info;
617 
618       // The g packet contents may either include the slice registers
619       // (registers defined in terms of other registers, e.g. eax is a subset
620       // of rax) or not.  The slice registers should NOT be in the g packet,
621       // but some implementations may incorrectly include them.
622       //
623       // If the slice registers are included in the packet, we must step over
624       // the slice registers when parsing the packet -- relying on the
625       // RegisterInfo byte_offset field would be incorrect. If the slice
626       // registers are not included, then using the byte_offset values into the
627       // data buffer is the best way to find individual register values.
628 
629       uint64_t size_including_slice_registers = 0;
630       uint64_t size_not_including_slice_registers = 0;
631       uint64_t size_by_highest_offset = 0;
632 
633       for (uint32_t reg_idx = 0;
634            (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr; ++reg_idx) {
635         size_including_slice_registers += reg_info->byte_size;
636         if (reg_info->value_regs == nullptr)
637           size_not_including_slice_registers += reg_info->byte_size;
638         if (reg_info->byte_offset >= size_by_highest_offset)
639           size_by_highest_offset = reg_info->byte_offset + reg_info->byte_size;
640       }
641 
642       bool use_byte_offset_into_buffer;
643       if (size_by_highest_offset == restore_data.GetByteSize()) {
644         // The size of the packet agrees with the highest offset: + size in the
645         // register file
646         use_byte_offset_into_buffer = true;
647       } else if (size_not_including_slice_registers ==
648                  restore_data.GetByteSize()) {
649         // The size of the packet is the same as concatenating all of the
650         // registers sequentially, skipping the slice registers
651         use_byte_offset_into_buffer = true;
652       } else if (size_including_slice_registers == restore_data.GetByteSize()) {
653         // The slice registers are present in the packet (when they shouldn't
654         // be). Don't try to use the RegisterInfo byte_offset into the
655         // restore_data, it will point to the wrong place.
656         use_byte_offset_into_buffer = false;
657       } else {
658         // None of our expected sizes match the actual g packet data we're
659         // looking at. The most conservative approach here is to use the
660         // running total byte offset.
661         use_byte_offset_into_buffer = false;
662       }
663 
664       // In case our register definitions don't include the correct offsets,
665       // keep track of the size of each reg & compute offset based on that.
666       uint32_t running_byte_offset = 0;
667       for (uint32_t reg_idx = 0;
668            (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr;
669            ++reg_idx, running_byte_offset += reg_info->byte_size) {
670         // Skip composite aka slice registers (e.g. eax is a slice of rax).
671         if (reg_info->value_regs)
672           continue;
673 
674         const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
675 
676         uint32_t register_offset;
677         if (use_byte_offset_into_buffer) {
678           register_offset = reg_info->byte_offset;
679         } else {
680           register_offset = running_byte_offset;
681         }
682 
683         const uint32_t reg_byte_size = reg_info->byte_size;
684 
685         const uint8_t *restore_src =
686             restore_data.PeekData(register_offset, reg_byte_size);
687         if (restore_src) {
688           SetRegisterIsValid(reg, false);
689           if (gdb_comm.WriteRegister(
690                   m_thread.GetProtocolID(),
691                   reg_info->kinds[eRegisterKindProcessPlugin],
692                   {restore_src, reg_byte_size}))
693             ++num_restored;
694         }
695       }
696       return num_restored > 0;
697     } else {
698       // For the use_g_packet == false case, we're going to write each register
699       // individually.  The data buffer is binary data in this case, instead of
700       // ascii characters.
701 
702       bool arm64_debugserver = false;
703       if (m_thread.GetProcess().get()) {
704         const ArchSpec &arch =
705             m_thread.GetProcess()->GetTarget().GetArchitecture();
706         if (arch.IsValid() && (arch.GetMachine() == llvm::Triple::aarch64 ||
707                                arch.GetMachine() == llvm::Triple::aarch64_32) &&
708             arch.GetTriple().getVendor() == llvm::Triple::Apple &&
709             arch.GetTriple().getOS() == llvm::Triple::IOS) {
710           arm64_debugserver = true;
711         }
712       }
713       uint32_t num_restored = 0;
714       const RegisterInfo *reg_info;
715       for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != nullptr;
716            i++) {
717         if (reg_info->value_regs) // skip registers that are slices of real
718                                   // registers
719           continue;
720         // Skip the fpsr and fpcr floating point status/control register
721         // writing to work around a bug in an older version of debugserver that
722         // would lead to register context corruption when writing fpsr/fpcr.
723         if (arm64_debugserver && (strcmp(reg_info->name, "fpsr") == 0 ||
724                                   strcmp(reg_info->name, "fpcr") == 0)) {
725           continue;
726         }
727 
728         SetRegisterIsValid(reg_info, false);
729         if (gdb_comm.WriteRegister(m_thread.GetProtocolID(),
730                                    reg_info->kinds[eRegisterKindProcessPlugin],
731                                    {data_sp->GetBytes() + reg_info->byte_offset,
732                                     reg_info->byte_size}))
733           ++num_restored;
734       }
735       return num_restored > 0;
736     }
737   } else {
738     Log *log(GetLog(GDBRLog::Thread | GDBRLog::Packets));
739     if (log) {
740       if (log->GetVerbose()) {
741         StreamString strm;
742         process->DumpPluginHistory(strm);
743         LLDB_LOGF(log,
744                   "error: failed to get packet sequence mutex, not sending "
745                   "write all registers:\n%s",
746                   strm.GetData());
747       } else
748         LLDB_LOGF(log,
749                   "error: failed to get packet sequence mutex, not sending "
750                   "write all registers");
751     }
752   }
753   return false;
754 }
755 
ConvertRegisterKindToRegisterNumber(lldb::RegisterKind kind,uint32_t num)756 uint32_t GDBRemoteRegisterContext::ConvertRegisterKindToRegisterNumber(
757     lldb::RegisterKind kind, uint32_t num) {
758   return m_reg_info_sp->ConvertRegisterKindToRegisterNumber(kind, num);
759 }
760 
RegisterWriteCausesReconfigure(const llvm::StringRef name)761 bool GDBRemoteRegisterContext::RegisterWriteCausesReconfigure(
762     const llvm::StringRef name) {
763   ExecutionContext exe_ctx(CalculateThread());
764   const Architecture *architecture =
765       exe_ctx.GetProcessRef().GetTarget().GetArchitecturePlugin();
766   return architecture && architecture->RegisterWriteCausesReconfigure(name);
767 }
768 
ReconfigureRegisterInfo()769 bool GDBRemoteRegisterContext::ReconfigureRegisterInfo() {
770   ExecutionContext exe_ctx(CalculateThread());
771   const Architecture *architecture =
772       exe_ctx.GetProcessRef().GetTarget().GetArchitecturePlugin();
773   if (architecture)
774     return architecture->ReconfigureRegisterInfo(*(m_reg_info_sp.get()),
775                                                  m_reg_data, *this);
776   return false;
777 }
778