xref: /freebsd-src/contrib/llvm-project/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp (revision 349cc55c9796c4596a5b9904cd3281af295f878f)
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 "lldb/Target/ExecutionContext.h"
12 #include "lldb/Target/Target.h"
13 #include "lldb/Utility/DataBufferHeap.h"
14 #include "lldb/Utility/DataExtractor.h"
15 #include "lldb/Utility/RegisterValue.h"
16 #include "lldb/Utility/Scalar.h"
17 #include "lldb/Utility/StreamString.h"
18 #include "ProcessGDBRemote.h"
19 #include "ProcessGDBRemoteLog.h"
20 #include "ThreadGDBRemote.h"
21 #include "Utility/ARM_DWARF_Registers.h"
22 #include "Utility/ARM_ehframe_Registers.h"
23 #include "lldb/Utility/StringExtractorGDBRemote.h"
24 
25 #include <memory>
26 
27 using namespace lldb;
28 using namespace lldb_private;
29 using namespace lldb_private::process_gdb_remote;
30 
31 // GDBRemoteRegisterContext constructor
32 GDBRemoteRegisterContext::GDBRemoteRegisterContext(
33     ThreadGDBRemote &thread, uint32_t concrete_frame_idx,
34     GDBRemoteDynamicRegisterInfoSP reg_info_sp, bool read_all_at_once,
35     bool write_all_at_once)
36     : RegisterContext(thread, concrete_frame_idx),
37       m_reg_info_sp(std::move(reg_info_sp)), m_reg_valid(), m_reg_data(),
38       m_read_all_at_once(read_all_at_once),
39       m_write_all_at_once(write_all_at_once), m_gpacket_cached(false) {
40   // Resize our vector of bools to contain one bool for every register. We will
41   // use these boolean values to know when a register value is valid in
42   // m_reg_data.
43   m_reg_valid.resize(m_reg_info_sp->GetNumRegisters());
44 
45   // Make a heap based buffer that is big enough to store all registers
46   DataBufferSP reg_data_sp(
47       new DataBufferHeap(m_reg_info_sp->GetRegisterDataByteSize(), 0));
48   m_reg_data.SetData(reg_data_sp);
49   m_reg_data.SetByteOrder(thread.GetProcess()->GetByteOrder());
50 }
51 
52 // Destructor
53 GDBRemoteRegisterContext::~GDBRemoteRegisterContext() = default;
54 
55 void GDBRemoteRegisterContext::InvalidateAllRegisters() {
56   SetAllRegisterValid(false);
57 }
58 
59 void GDBRemoteRegisterContext::SetAllRegisterValid(bool b) {
60   m_gpacket_cached = b;
61   std::vector<bool>::iterator pos, end = m_reg_valid.end();
62   for (pos = m_reg_valid.begin(); pos != end; ++pos)
63     *pos = b;
64 }
65 
66 size_t GDBRemoteRegisterContext::GetRegisterCount() {
67   return m_reg_info_sp->GetNumRegisters();
68 }
69 
70 const RegisterInfo *
71 GDBRemoteRegisterContext::GetRegisterInfoAtIndex(size_t reg) {
72   return m_reg_info_sp->GetRegisterInfoAtIndex(reg);
73 }
74 
75 size_t GDBRemoteRegisterContext::GetRegisterSetCount() {
76   return m_reg_info_sp->GetNumRegisterSets();
77 }
78 
79 const RegisterSet *GDBRemoteRegisterContext::GetRegisterSet(size_t reg_set) {
80   return m_reg_info_sp->GetRegisterSet(reg_set);
81 }
82 
83 bool GDBRemoteRegisterContext::ReadRegister(const RegisterInfo *reg_info,
84                                             RegisterValue &value) {
85   // Read the register
86   if (ReadRegisterBytes(reg_info)) {
87     const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
88     if (m_reg_valid[reg] == false)
89       return false;
90     if (reg_info->value_regs &&
91         reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
92         reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
93       std::vector<char> combined_data;
94       uint32_t offset = 0;
95       for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
96         const RegisterInfo *parent_reg = GetRegisterInfo(
97             eRegisterKindLLDB, reg_info->value_regs[i]);
98         if (!parent_reg)
99           return false;
100         combined_data.resize(offset + parent_reg->byte_size);
101         if (m_reg_data.CopyData(parent_reg->byte_offset, parent_reg->byte_size,
102                                 combined_data.data() + offset) !=
103             parent_reg->byte_size)
104           return false;
105         offset += parent_reg->byte_size;
106       }
107 
108       Status error;
109       return value.SetFromMemoryData(
110                  reg_info, combined_data.data(), combined_data.size(),
111                  m_reg_data.GetByteOrder(), error) == combined_data.size();
112     } else {
113       const bool partial_data_ok = false;
114       Status error(value.SetValueFromData(
115           reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
116       return error.Success();
117     }
118   }
119   return false;
120 }
121 
122 bool GDBRemoteRegisterContext::PrivateSetRegisterValue(
123     uint32_t reg, llvm::ArrayRef<uint8_t> data) {
124   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
125   if (reg_info == nullptr)
126     return false;
127 
128   // Invalidate if needed
129   InvalidateIfNeeded(false);
130 
131   const size_t reg_byte_size = reg_info->byte_size;
132   memcpy(const_cast<uint8_t *>(
133              m_reg_data.PeekData(reg_info->byte_offset, reg_byte_size)),
134          data.data(), std::min(data.size(), reg_byte_size));
135   bool success = data.size() >= reg_byte_size;
136   if (success) {
137     SetRegisterIsValid(reg, true);
138   } else if (data.size() > 0) {
139     // Only set register is valid to false if we copied some bytes, else leave
140     // it as it was.
141     SetRegisterIsValid(reg, false);
142   }
143   return success;
144 }
145 
146 bool GDBRemoteRegisterContext::PrivateSetRegisterValue(uint32_t reg,
147                                                        uint64_t new_reg_val) {
148   const RegisterInfo *reg_info = GetRegisterInfoAtIndex(reg);
149   if (reg_info == nullptr)
150     return false;
151 
152   // Early in process startup, we can get a thread that has an invalid byte
153   // order because the process hasn't been completely set up yet (see the ctor
154   // where the byte order is setfrom the process).  If that's the case, we
155   // can't set the value here.
156   if (m_reg_data.GetByteOrder() == eByteOrderInvalid) {
157     return false;
158   }
159 
160   // Invalidate if needed
161   InvalidateIfNeeded(false);
162 
163   DataBufferSP buffer_sp(new DataBufferHeap(&new_reg_val, sizeof(new_reg_val)));
164   DataExtractor data(buffer_sp, endian::InlHostByteOrder(), sizeof(void *));
165 
166   // If our register context and our register info disagree, which should never
167   // happen, don't overwrite past the end of the buffer.
168   if (m_reg_data.GetByteSize() < reg_info->byte_offset + reg_info->byte_size)
169     return false;
170 
171   // Grab a pointer to where we are going to put this register
172   uint8_t *dst = const_cast<uint8_t *>(
173       m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
174 
175   if (dst == nullptr)
176     return false;
177 
178   if (data.CopyByteOrderedData(0,                          // src offset
179                                reg_info->byte_size,        // src length
180                                dst,                        // dst
181                                reg_info->byte_size,        // dst length
182                                m_reg_data.GetByteOrder())) // dst byte order
183   {
184     SetRegisterIsValid(reg, true);
185     return true;
186   }
187   return false;
188 }
189 
190 // Helper function for GDBRemoteRegisterContext::ReadRegisterBytes().
191 bool GDBRemoteRegisterContext::GetPrimordialRegister(
192     const RegisterInfo *reg_info, GDBRemoteCommunicationClient &gdb_comm) {
193   const uint32_t lldb_reg = reg_info->kinds[eRegisterKindLLDB];
194   const uint32_t remote_reg = reg_info->kinds[eRegisterKindProcessPlugin];
195 
196   if (DataBufferSP buffer_sp =
197           gdb_comm.ReadRegister(m_thread.GetProtocolID(), remote_reg))
198     return PrivateSetRegisterValue(
199         lldb_reg, llvm::ArrayRef<uint8_t>(buffer_sp->GetBytes(),
200                                           buffer_sp->GetByteSize()));
201   return false;
202 }
203 
204 bool GDBRemoteRegisterContext::ReadRegisterBytes(const RegisterInfo *reg_info) {
205   ExecutionContext exe_ctx(CalculateThread());
206 
207   Process *process = exe_ctx.GetProcessPtr();
208   Thread *thread = exe_ctx.GetThreadPtr();
209   if (process == nullptr || thread == nullptr)
210     return false;
211 
212   GDBRemoteCommunicationClient &gdb_comm(
213       ((ProcessGDBRemote *)process)->GetGDBRemote());
214 
215   InvalidateIfNeeded(false);
216 
217   const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
218 
219   if (!GetRegisterIsValid(reg)) {
220     if (m_read_all_at_once && !m_gpacket_cached) {
221       if (DataBufferSP buffer_sp =
222               gdb_comm.ReadAllRegisters(m_thread.GetProtocolID())) {
223         memcpy(const_cast<uint8_t *>(m_reg_data.GetDataStart()),
224                buffer_sp->GetBytes(),
225                std::min(buffer_sp->GetByteSize(), m_reg_data.GetByteSize()));
226         if (buffer_sp->GetByteSize() >= m_reg_data.GetByteSize()) {
227           SetAllRegisterValid(true);
228           return true;
229         } else if (buffer_sp->GetByteSize() > 0) {
230           for (auto x : llvm::enumerate(m_reg_info_sp->registers())) {
231             const struct RegisterInfo &reginfo = x.value();
232             m_reg_valid[x.index()] =
233                 (reginfo.byte_offset + reginfo.byte_size <=
234                  buffer_sp->GetByteSize());
235           }
236 
237           m_gpacket_cached = true;
238           if (GetRegisterIsValid(reg))
239             return true;
240         } else {
241           Log *log(ProcessGDBRemoteLog::GetLogIfAnyCategoryIsSet(GDBR_LOG_THREAD |
242                                                                 GDBR_LOG_PACKETS));
243           LLDB_LOGF(
244               log,
245               "error: GDBRemoteRegisterContext::ReadRegisterBytes tried "
246               "to read the "
247               "entire register context at once, expected at least %" PRId64
248               " bytes "
249               "but only got %" PRId64 " bytes.",
250               m_reg_data.GetByteSize(), buffer_sp->GetByteSize());
251           return false;
252         }
253       }
254     }
255     if (reg_info->value_regs) {
256       // Process this composite register request by delegating to the
257       // constituent primordial registers.
258 
259       // Index of the primordial register.
260       bool success = true;
261       for (uint32_t idx = 0; success; ++idx) {
262         const uint32_t prim_reg = reg_info->value_regs[idx];
263         if (prim_reg == LLDB_INVALID_REGNUM)
264           break;
265         // We have a valid primordial register as our constituent. Grab the
266         // corresponding register info.
267         const RegisterInfo *prim_reg_info =
268             GetRegisterInfo(eRegisterKindLLDB, prim_reg);
269         if (prim_reg_info == nullptr)
270           success = false;
271         else {
272           // Read the containing register if it hasn't already been read
273           if (!GetRegisterIsValid(prim_reg))
274             success = GetPrimordialRegister(prim_reg_info, gdb_comm);
275         }
276       }
277 
278       if (success) {
279         // If we reach this point, all primordial register requests have
280         // succeeded. Validate this composite register.
281         SetRegisterIsValid(reg_info, true);
282       }
283     } else {
284       // Get each register individually
285       GetPrimordialRegister(reg_info, gdb_comm);
286     }
287 
288     // Make sure we got a valid register value after reading it
289     if (!GetRegisterIsValid(reg))
290       return false;
291   }
292 
293   return true;
294 }
295 
296 bool GDBRemoteRegisterContext::WriteRegister(const RegisterInfo *reg_info,
297                                              const RegisterValue &value) {
298   DataExtractor data;
299   if (value.GetData(data)) {
300     if (reg_info->value_regs &&
301         reg_info->value_regs[0] != LLDB_INVALID_REGNUM &&
302         reg_info->value_regs[1] != LLDB_INVALID_REGNUM) {
303       uint32_t combined_size = 0;
304       for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
305         const RegisterInfo *parent_reg = GetRegisterInfo(
306             eRegisterKindLLDB, reg_info->value_regs[i]);
307         if (!parent_reg)
308           return false;
309         combined_size += parent_reg->byte_size;
310       }
311 
312       if (data.GetByteSize() < combined_size)
313         return false;
314 
315       uint32_t offset = 0;
316       for (int i = 0; reg_info->value_regs[i] != LLDB_INVALID_REGNUM; i++) {
317         const RegisterInfo *parent_reg = GetRegisterInfo(
318             eRegisterKindLLDB, reg_info->value_regs[i]);
319         assert(parent_reg);
320 
321         DataExtractor parent_data{data, offset, parent_reg->byte_size};
322         if (!WriteRegisterBytes(parent_reg, parent_data, 0))
323           return false;
324         offset += parent_reg->byte_size;
325       }
326       assert(offset == combined_size);
327       return true;
328     } else
329       return WriteRegisterBytes(reg_info, data, 0);
330   }
331   return false;
332 }
333 
334 // Helper function for GDBRemoteRegisterContext::WriteRegisterBytes().
335 bool GDBRemoteRegisterContext::SetPrimordialRegister(
336     const RegisterInfo *reg_info, GDBRemoteCommunicationClient &gdb_comm) {
337   StreamString packet;
338   StringExtractorGDBRemote response;
339   const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
340   // Invalidate just this register
341   SetRegisterIsValid(reg, false);
342 
343   return gdb_comm.WriteRegister(
344       m_thread.GetProtocolID(), reg_info->kinds[eRegisterKindProcessPlugin],
345       {m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size),
346        reg_info->byte_size});
347 }
348 
349 bool GDBRemoteRegisterContext::WriteRegisterBytes(const RegisterInfo *reg_info,
350                                                   DataExtractor &data,
351                                                   uint32_t data_offset) {
352   ExecutionContext exe_ctx(CalculateThread());
353 
354   Process *process = exe_ctx.GetProcessPtr();
355   Thread *thread = exe_ctx.GetThreadPtr();
356   if (process == nullptr || thread == nullptr)
357     return false;
358 
359   GDBRemoteCommunicationClient &gdb_comm(
360       ((ProcessGDBRemote *)process)->GetGDBRemote());
361 
362   assert(m_reg_data.GetByteSize() >=
363          reg_info->byte_offset + reg_info->byte_size);
364 
365   // If our register context and our register info disagree, which should never
366   // happen, don't overwrite past the end of the buffer.
367   if (m_reg_data.GetByteSize() < reg_info->byte_offset + reg_info->byte_size)
368     return false;
369 
370   // Grab a pointer to where we are going to put this register
371   uint8_t *dst = const_cast<uint8_t *>(
372       m_reg_data.PeekData(reg_info->byte_offset, reg_info->byte_size));
373 
374   if (dst == nullptr)
375     return false;
376 
377   // Code below is specific to AArch64 target in SVE state
378   // If vector granule (vg) register is being written then thread's
379   // register context reconfiguration is triggered on success.
380   bool do_reconfigure_arm64_sve = false;
381   const ArchSpec &arch = process->GetTarget().GetArchitecture();
382   if (arch.IsValid() && arch.GetTriple().isAArch64())
383     if (strcmp(reg_info->name, "vg") == 0)
384       do_reconfigure_arm64_sve = true;
385 
386   if (data.CopyByteOrderedData(data_offset,                // src offset
387                                reg_info->byte_size,        // src length
388                                dst,                        // dst
389                                reg_info->byte_size,        // dst length
390                                m_reg_data.GetByteOrder())) // dst byte order
391   {
392     GDBRemoteClientBase::Lock lock(gdb_comm);
393     if (lock) {
394       if (m_write_all_at_once) {
395         // Invalidate all register values
396         InvalidateIfNeeded(true);
397 
398         // Set all registers in one packet
399         if (gdb_comm.WriteAllRegisters(
400                 m_thread.GetProtocolID(),
401                 {m_reg_data.GetDataStart(), size_t(m_reg_data.GetByteSize())}))
402 
403         {
404           SetAllRegisterValid(false);
405 
406           if (do_reconfigure_arm64_sve)
407             AArch64SVEReconfigure();
408 
409           return true;
410         }
411       } else {
412         bool success = true;
413 
414         if (reg_info->value_regs) {
415           // This register is part of another register. In this case we read
416           // the actual register data for any "value_regs", and once all that
417           // data is read, we will have enough data in our register context
418           // bytes for the value of this register
419 
420           // Invalidate this composite register first.
421 
422           for (uint32_t idx = 0; success; ++idx) {
423             const uint32_t reg = reg_info->value_regs[idx];
424             if (reg == LLDB_INVALID_REGNUM)
425               break;
426             // We have a valid primordial register as our constituent. Grab the
427             // corresponding register info.
428             const RegisterInfo *value_reg_info =
429                 GetRegisterInfo(eRegisterKindLLDB, reg);
430             if (value_reg_info == nullptr)
431               success = false;
432             else
433               success = SetPrimordialRegister(value_reg_info, gdb_comm);
434           }
435         } else {
436           // This is an actual register, write it
437           success = SetPrimordialRegister(reg_info, gdb_comm);
438 
439           if (success && do_reconfigure_arm64_sve)
440             AArch64SVEReconfigure();
441         }
442 
443         // Check if writing this register will invalidate any other register
444         // values? If so, invalidate them
445         if (reg_info->invalidate_regs) {
446           for (uint32_t idx = 0, reg = reg_info->invalidate_regs[0];
447                reg != LLDB_INVALID_REGNUM;
448                reg = reg_info->invalidate_regs[++idx])
449             SetRegisterIsValid(ConvertRegisterKindToRegisterNumber(
450                                    eRegisterKindLLDB, reg),
451                                false);
452         }
453 
454         return success;
455       }
456     } else {
457       Log *log(ProcessGDBRemoteLog::GetLogIfAnyCategoryIsSet(GDBR_LOG_THREAD |
458                                                              GDBR_LOG_PACKETS));
459       if (log) {
460         if (log->GetVerbose()) {
461           StreamString strm;
462           gdb_comm.DumpHistory(strm);
463           LLDB_LOGF(log,
464                     "error: failed to get packet sequence mutex, not sending "
465                     "write register for \"%s\":\n%s",
466                     reg_info->name, strm.GetData());
467         } else
468           LLDB_LOGF(log,
469                     "error: failed to get packet sequence mutex, not sending "
470                     "write register for \"%s\"",
471                     reg_info->name);
472       }
473     }
474   }
475   return false;
476 }
477 
478 bool GDBRemoteRegisterContext::ReadAllRegisterValues(
479     RegisterCheckpoint &reg_checkpoint) {
480   ExecutionContext exe_ctx(CalculateThread());
481 
482   Process *process = exe_ctx.GetProcessPtr();
483   Thread *thread = exe_ctx.GetThreadPtr();
484   if (process == nullptr || thread == nullptr)
485     return false;
486 
487   GDBRemoteCommunicationClient &gdb_comm(
488       ((ProcessGDBRemote *)process)->GetGDBRemote());
489 
490   uint32_t save_id = 0;
491   if (gdb_comm.SaveRegisterState(thread->GetProtocolID(), save_id)) {
492     reg_checkpoint.SetID(save_id);
493     reg_checkpoint.GetData().reset();
494     return true;
495   } else {
496     reg_checkpoint.SetID(0); // Invalid save ID is zero
497     return ReadAllRegisterValues(reg_checkpoint.GetData());
498   }
499 }
500 
501 bool GDBRemoteRegisterContext::WriteAllRegisterValues(
502     const RegisterCheckpoint &reg_checkpoint) {
503   uint32_t save_id = reg_checkpoint.GetID();
504   if (save_id != 0) {
505     ExecutionContext exe_ctx(CalculateThread());
506 
507     Process *process = exe_ctx.GetProcessPtr();
508     Thread *thread = exe_ctx.GetThreadPtr();
509     if (process == nullptr || thread == nullptr)
510       return false;
511 
512     GDBRemoteCommunicationClient &gdb_comm(
513         ((ProcessGDBRemote *)process)->GetGDBRemote());
514 
515     return gdb_comm.RestoreRegisterState(m_thread.GetProtocolID(), save_id);
516   } else {
517     return WriteAllRegisterValues(reg_checkpoint.GetData());
518   }
519 }
520 
521 bool GDBRemoteRegisterContext::ReadAllRegisterValues(
522     lldb::DataBufferSP &data_sp) {
523   ExecutionContext exe_ctx(CalculateThread());
524 
525   Process *process = exe_ctx.GetProcessPtr();
526   Thread *thread = exe_ctx.GetThreadPtr();
527   if (process == nullptr || thread == nullptr)
528     return false;
529 
530   GDBRemoteCommunicationClient &gdb_comm(
531       ((ProcessGDBRemote *)process)->GetGDBRemote());
532 
533   const bool use_g_packet =
534       !gdb_comm.AvoidGPackets((ProcessGDBRemote *)process);
535 
536   GDBRemoteClientBase::Lock lock(gdb_comm);
537   if (lock) {
538     if (gdb_comm.SyncThreadState(m_thread.GetProtocolID()))
539       InvalidateAllRegisters();
540 
541     if (use_g_packet &&
542         (data_sp = gdb_comm.ReadAllRegisters(m_thread.GetProtocolID())))
543       return true;
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(ProcessGDBRemoteLog::GetLogIfAnyCategoryIsSet(GDBR_LOG_THREAD |
564                                                            GDBR_LOG_PACKETS));
565     if (log) {
566       if (log->GetVerbose()) {
567         StreamString strm;
568         gdb_comm.DumpHistory(strm);
569         LLDB_LOGF(log,
570                   "error: failed to get packet sequence mutex, not sending "
571                   "read all registers:\n%s",
572                   strm.GetData());
573       } else
574         LLDB_LOGF(log,
575                   "error: failed to get packet sequence mutex, not sending "
576                   "read all registers");
577     }
578   }
579 
580   data_sp.reset();
581   return false;
582 }
583 
584 bool GDBRemoteRegisterContext::WriteAllRegisterValues(
585     const lldb::DataBufferSP &data_sp) {
586   if (!data_sp || data_sp->GetBytes() == nullptr || data_sp->GetByteSize() == 0)
587     return false;
588 
589   ExecutionContext exe_ctx(CalculateThread());
590 
591   Process *process = exe_ctx.GetProcessPtr();
592   Thread *thread = exe_ctx.GetThreadPtr();
593   if (process == nullptr || thread == nullptr)
594     return false;
595 
596   GDBRemoteCommunicationClient &gdb_comm(
597       ((ProcessGDBRemote *)process)->GetGDBRemote());
598 
599   const bool use_g_packet =
600       !gdb_comm.AvoidGPackets((ProcessGDBRemote *)process);
601 
602   GDBRemoteClientBase::Lock lock(gdb_comm);
603   if (lock) {
604     // The data_sp contains the G response packet.
605     if (use_g_packet) {
606       if (gdb_comm.WriteAllRegisters(
607               m_thread.GetProtocolID(),
608               {data_sp->GetBytes(), size_t(data_sp->GetByteSize())}))
609         return true;
610 
611       uint32_t num_restored = 0;
612       // We need to manually go through all of the registers and restore them
613       // manually
614       DataExtractor restore_data(data_sp, m_reg_data.GetByteOrder(),
615                                  m_reg_data.GetAddressByteSize());
616 
617       const RegisterInfo *reg_info;
618 
619       // The g packet contents may either include the slice registers
620       // (registers defined in terms of other registers, e.g. eax is a subset
621       // of rax) or not.  The slice registers should NOT be in the g packet,
622       // but some implementations may incorrectly include them.
623       //
624       // If the slice registers are included in the packet, we must step over
625       // the slice registers when parsing the packet -- relying on the
626       // RegisterInfo byte_offset field would be incorrect. If the slice
627       // registers are not included, then using the byte_offset values into the
628       // data buffer is the best way to find individual register values.
629 
630       uint64_t size_including_slice_registers = 0;
631       uint64_t size_not_including_slice_registers = 0;
632       uint64_t size_by_highest_offset = 0;
633 
634       for (uint32_t reg_idx = 0;
635            (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr; ++reg_idx) {
636         size_including_slice_registers += reg_info->byte_size;
637         if (reg_info->value_regs == nullptr)
638           size_not_including_slice_registers += reg_info->byte_size;
639         if (reg_info->byte_offset >= size_by_highest_offset)
640           size_by_highest_offset = reg_info->byte_offset + reg_info->byte_size;
641       }
642 
643       bool use_byte_offset_into_buffer;
644       if (size_by_highest_offset == restore_data.GetByteSize()) {
645         // The size of the packet agrees with the highest offset: + size in the
646         // register file
647         use_byte_offset_into_buffer = true;
648       } else if (size_not_including_slice_registers ==
649                  restore_data.GetByteSize()) {
650         // The size of the packet is the same as concatenating all of the
651         // registers sequentially, skipping the slice registers
652         use_byte_offset_into_buffer = true;
653       } else if (size_including_slice_registers == restore_data.GetByteSize()) {
654         // The slice registers are present in the packet (when they shouldn't
655         // be). Don't try to use the RegisterInfo byte_offset into the
656         // restore_data, it will point to the wrong place.
657         use_byte_offset_into_buffer = false;
658       } else {
659         // None of our expected sizes match the actual g packet data we're
660         // looking at. The most conservative approach here is to use the
661         // running total byte offset.
662         use_byte_offset_into_buffer = false;
663       }
664 
665       // In case our register definitions don't include the correct offsets,
666       // keep track of the size of each reg & compute offset based on that.
667       uint32_t running_byte_offset = 0;
668       for (uint32_t reg_idx = 0;
669            (reg_info = GetRegisterInfoAtIndex(reg_idx)) != nullptr;
670            ++reg_idx, running_byte_offset += reg_info->byte_size) {
671         // Skip composite aka slice registers (e.g. eax is a slice of rax).
672         if (reg_info->value_regs)
673           continue;
674 
675         const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
676 
677         uint32_t register_offset;
678         if (use_byte_offset_into_buffer) {
679           register_offset = reg_info->byte_offset;
680         } else {
681           register_offset = running_byte_offset;
682         }
683 
684         const uint32_t reg_byte_size = reg_info->byte_size;
685 
686         const uint8_t *restore_src =
687             restore_data.PeekData(register_offset, reg_byte_size);
688         if (restore_src) {
689           SetRegisterIsValid(reg, false);
690           if (gdb_comm.WriteRegister(
691                   m_thread.GetProtocolID(),
692                   reg_info->kinds[eRegisterKindProcessPlugin],
693                   {restore_src, reg_byte_size}))
694             ++num_restored;
695         }
696       }
697       return num_restored > 0;
698     } else {
699       // For the use_g_packet == false case, we're going to write each register
700       // individually.  The data buffer is binary data in this case, instead of
701       // ascii characters.
702 
703       bool arm64_debugserver = false;
704       if (m_thread.GetProcess().get()) {
705         const ArchSpec &arch =
706             m_thread.GetProcess()->GetTarget().GetArchitecture();
707         if (arch.IsValid() && (arch.GetMachine() == llvm::Triple::aarch64 ||
708                                arch.GetMachine() == llvm::Triple::aarch64_32) &&
709             arch.GetTriple().getVendor() == llvm::Triple::Apple &&
710             arch.GetTriple().getOS() == llvm::Triple::IOS) {
711           arm64_debugserver = true;
712         }
713       }
714       uint32_t num_restored = 0;
715       const RegisterInfo *reg_info;
716       for (uint32_t i = 0; (reg_info = GetRegisterInfoAtIndex(i)) != nullptr;
717            i++) {
718         if (reg_info->value_regs) // skip registers that are slices of real
719                                   // registers
720           continue;
721         // Skip the fpsr and fpcr floating point status/control register
722         // writing to work around a bug in an older version of debugserver that
723         // would lead to register context corruption when writing fpsr/fpcr.
724         if (arm64_debugserver && (strcmp(reg_info->name, "fpsr") == 0 ||
725                                   strcmp(reg_info->name, "fpcr") == 0)) {
726           continue;
727         }
728 
729         SetRegisterIsValid(reg_info, false);
730         if (gdb_comm.WriteRegister(m_thread.GetProtocolID(),
731                                    reg_info->kinds[eRegisterKindProcessPlugin],
732                                    {data_sp->GetBytes() + reg_info->byte_offset,
733                                     reg_info->byte_size}))
734           ++num_restored;
735       }
736       return num_restored > 0;
737     }
738   } else {
739     Log *log(ProcessGDBRemoteLog::GetLogIfAnyCategoryIsSet(GDBR_LOG_THREAD |
740                                                            GDBR_LOG_PACKETS));
741     if (log) {
742       if (log->GetVerbose()) {
743         StreamString strm;
744         gdb_comm.DumpHistory(strm);
745         LLDB_LOGF(log,
746                   "error: failed to get packet sequence mutex, not sending "
747                   "write all registers:\n%s",
748                   strm.GetData());
749       } else
750         LLDB_LOGF(log,
751                   "error: failed to get packet sequence mutex, not sending "
752                   "write all registers");
753     }
754   }
755   return false;
756 }
757 
758 uint32_t GDBRemoteRegisterContext::ConvertRegisterKindToRegisterNumber(
759     lldb::RegisterKind kind, uint32_t num) {
760   return m_reg_info_sp->ConvertRegisterKindToRegisterNumber(kind, num);
761 }
762 
763 bool GDBRemoteRegisterContext::AArch64SVEReconfigure() {
764   if (!m_reg_info_sp)
765     return false;
766 
767   const RegisterInfo *reg_info = m_reg_info_sp->GetRegisterInfo("vg");
768   if (!reg_info)
769     return false;
770 
771   uint64_t fail_value = LLDB_INVALID_ADDRESS;
772   uint32_t vg_reg_num = reg_info->kinds[eRegisterKindLLDB];
773   uint64_t vg_reg_value = ReadRegisterAsUnsigned(vg_reg_num, fail_value);
774 
775   if (vg_reg_value != fail_value && vg_reg_value <= 32) {
776     const RegisterInfo *reg_info = m_reg_info_sp->GetRegisterInfo("p0");
777     if (!reg_info || vg_reg_value == reg_info->byte_size)
778       return false;
779 
780     if (m_reg_info_sp->UpdateARM64SVERegistersInfos(vg_reg_value)) {
781       // Make a heap based buffer that is big enough to store all registers
782       m_reg_data.SetData(std::make_shared<DataBufferHeap>(
783           m_reg_info_sp->GetRegisterDataByteSize(), 0));
784       m_reg_data.SetByteOrder(GetByteOrder());
785 
786       InvalidateAllRegisters();
787 
788       return true;
789     }
790   }
791 
792   return false;
793 }
794 
795 bool GDBRemoteDynamicRegisterInfo::UpdateARM64SVERegistersInfos(uint64_t vg) {
796   // SVE Z register size is vg x 8 bytes.
797   uint32_t z_reg_byte_size = vg * 8;
798 
799   // SVE vector length has changed, accordingly set size of Z, P and FFR
800   // registers. Also invalidate register offsets it will be recalculated
801   // after SVE register size update.
802   for (auto &reg : m_regs) {
803     if (reg.value_regs == nullptr) {
804       if (reg.name[0] == 'z' && isdigit(reg.name[1]))
805         reg.byte_size = z_reg_byte_size;
806       else if (reg.name[0] == 'p' && isdigit(reg.name[1]))
807         reg.byte_size = vg;
808       else if (strcmp(reg.name, "ffr") == 0)
809         reg.byte_size = vg;
810     }
811     reg.byte_offset = LLDB_INVALID_INDEX32;
812   }
813 
814   // Re-calculate register offsets
815   ConfigureOffsets();
816   return true;
817 }
818