xref: /llvm-project/lldb/source/Plugins/Process/FreeBSD/NativeRegisterContextFreeBSD_arm64.cpp (revision ad5e2bf6e934abd9fef39d3b88f40d4f3c1a7d60)
1 //===-- NativeRegisterContextFreeBSD_arm64.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 #if defined(__aarch64__)
10 
11 #include "NativeRegisterContextFreeBSD_arm64.h"
12 
13 #include "lldb/Utility/DataBufferHeap.h"
14 #include "lldb/Utility/RegisterValue.h"
15 #include "lldb/Utility/Status.h"
16 
17 #include "Plugins/Process/FreeBSD/NativeProcessFreeBSD.h"
18 #include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
19 #include "Plugins/Process/Utility/RegisterFlagsDetector_arm64.h"
20 #include "Plugins/Process/Utility/RegisterInfoPOSIX_arm64.h"
21 
22 // clang-format off
23 #include <sys/param.h>
24 #include <sys/ptrace.h>
25 #include <sys/types.h>
26 // clang-format on
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 using namespace lldb_private::process_freebsd;
31 
32 // A NativeRegisterContext is constructed per thread, but all threads' registers
33 // will contain the same fields. Therefore this mutex prevents each instance
34 // competing with the other, and subsequent instances from having to detect the
35 // fields all over again.
36 static std::mutex g_register_flags_detector_mutex;
37 static Arm64RegisterFlagsDetector g_register_flags_detector;
38 
39 NativeRegisterContextFreeBSD *
40 NativeRegisterContextFreeBSD::CreateHostNativeRegisterContextFreeBSD(
41     const ArchSpec &target_arch, NativeThreadFreeBSD &native_thread) {
42   std::lock_guard<std::mutex> lock(g_register_flags_detector_mutex);
43   if (!g_register_flags_detector.HasDetected()) {
44     NativeProcessFreeBSD &process = native_thread.GetProcess();
45     g_register_flags_detector.DetectFields(
46         process.GetAuxValue(AuxVector::AUXV_FREEBSD_AT_HWCAP).value_or(0),
47         process.GetAuxValue(AuxVector::AUXV_AT_HWCAP2).value_or(0));
48   }
49 
50   return new NativeRegisterContextFreeBSD_arm64(target_arch, native_thread);
51 }
52 
53 NativeRegisterContextFreeBSD_arm64::NativeRegisterContextFreeBSD_arm64(
54     const ArchSpec &target_arch, NativeThreadFreeBSD &native_thread)
55     : NativeRegisterContextRegisterInfo(
56           native_thread, new RegisterInfoPOSIX_arm64(target_arch, 0))
57 #ifdef LLDB_HAS_FREEBSD_WATCHPOINT
58       ,
59       m_read_dbreg(false)
60 #endif
61 {
62   g_register_flags_detector.UpdateRegisterInfo(
63       GetRegisterInfoInterface().GetRegisterInfo(),
64       GetRegisterInfoInterface().GetRegisterCount());
65 
66   ::memset(&m_hwp_regs, 0, sizeof(m_hwp_regs));
67   ::memset(&m_hbp_regs, 0, sizeof(m_hbp_regs));
68 }
69 
70 RegisterInfoPOSIX_arm64 &
71 NativeRegisterContextFreeBSD_arm64::GetRegisterInfo() const {
72   return static_cast<RegisterInfoPOSIX_arm64 &>(*m_register_info_interface_up);
73 }
74 
75 uint32_t NativeRegisterContextFreeBSD_arm64::GetRegisterSetCount() const {
76   return GetRegisterInfo().GetRegisterSetCount();
77 }
78 
79 const RegisterSet *
80 NativeRegisterContextFreeBSD_arm64::GetRegisterSet(uint32_t set_index) const {
81   return GetRegisterInfo().GetRegisterSet(set_index);
82 }
83 
84 uint32_t NativeRegisterContextFreeBSD_arm64::GetUserRegisterCount() const {
85   uint32_t count = 0;
86   for (uint32_t set_index = 0; set_index < GetRegisterSetCount(); ++set_index)
87     count += GetRegisterSet(set_index)->num_registers;
88   return count;
89 }
90 
91 Status NativeRegisterContextFreeBSD_arm64::ReadRegisterSet(uint32_t set) {
92   switch (set) {
93   case RegisterInfoPOSIX_arm64::GPRegSet:
94     return NativeProcessFreeBSD::PtraceWrapper(PT_GETREGS, m_thread.GetID(),
95                                                m_reg_data.data());
96   case RegisterInfoPOSIX_arm64::FPRegSet:
97     return NativeProcessFreeBSD::PtraceWrapper(
98         PT_GETFPREGS, m_thread.GetID(),
99         m_reg_data.data() + sizeof(RegisterInfoPOSIX_arm64::GPR));
100   }
101   llvm_unreachable("NativeRegisterContextFreeBSD_arm64::ReadRegisterSet");
102 }
103 
104 Status NativeRegisterContextFreeBSD_arm64::WriteRegisterSet(uint32_t set) {
105   switch (set) {
106   case RegisterInfoPOSIX_arm64::GPRegSet:
107     return NativeProcessFreeBSD::PtraceWrapper(PT_SETREGS, m_thread.GetID(),
108                                                m_reg_data.data());
109   case RegisterInfoPOSIX_arm64::FPRegSet:
110     return NativeProcessFreeBSD::PtraceWrapper(
111         PT_SETFPREGS, m_thread.GetID(),
112         m_reg_data.data() + sizeof(RegisterInfoPOSIX_arm64::GPR));
113   }
114   llvm_unreachable("NativeRegisterContextFreeBSD_arm64::WriteRegisterSet");
115 }
116 
117 Status
118 NativeRegisterContextFreeBSD_arm64::ReadRegister(const RegisterInfo *reg_info,
119                                                  RegisterValue &reg_value) {
120   Status error;
121 
122   if (!reg_info)
123     return Status::FromErrorString("reg_info NULL");
124 
125   const uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
126 
127   if (reg == LLDB_INVALID_REGNUM)
128     return Status::FromErrorStringWithFormat(
129         "no lldb regnum for %s",
130         reg_info && reg_info->name ? reg_info->name : "<unknown register>");
131 
132   uint32_t set = GetRegisterInfo().GetRegisterSetFromRegisterIndex(reg);
133   error = ReadRegisterSet(set);
134   if (error.Fail())
135     return error;
136 
137   assert(reg_info->byte_offset + reg_info->byte_size <= m_reg_data.size());
138   reg_value.SetBytes(m_reg_data.data() + reg_info->byte_offset,
139                      reg_info->byte_size, endian::InlHostByteOrder());
140   return error;
141 }
142 
143 Status NativeRegisterContextFreeBSD_arm64::WriteRegister(
144     const RegisterInfo *reg_info, const RegisterValue &reg_value) {
145   Status error;
146 
147   if (!reg_info)
148     return Status::FromErrorString("reg_info NULL");
149 
150   const uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
151 
152   if (reg == LLDB_INVALID_REGNUM)
153     return Status::FromErrorStringWithFormat(
154         "no lldb regnum for %s",
155         reg_info && reg_info->name ? reg_info->name : "<unknown register>");
156 
157   uint32_t set = GetRegisterInfo().GetRegisterSetFromRegisterIndex(reg);
158   error = ReadRegisterSet(set);
159   if (error.Fail())
160     return error;
161 
162   assert(reg_info->byte_offset + reg_info->byte_size <= m_reg_data.size());
163   ::memcpy(m_reg_data.data() + reg_info->byte_offset, reg_value.GetBytes(),
164            reg_info->byte_size);
165 
166   return WriteRegisterSet(set);
167 }
168 
169 Status NativeRegisterContextFreeBSD_arm64::ReadAllRegisterValues(
170     lldb::WritableDataBufferSP &data_sp) {
171   Status error;
172 
173   error = ReadRegisterSet(RegisterInfoPOSIX_arm64::GPRegSet);
174   if (error.Fail())
175     return error;
176 
177   error = ReadRegisterSet(RegisterInfoPOSIX_arm64::FPRegSet);
178   if (error.Fail())
179     return error;
180 
181   data_sp.reset(new DataBufferHeap(m_reg_data.size(), 0));
182   uint8_t *dst = data_sp->GetBytes();
183   ::memcpy(dst, m_reg_data.data(), m_reg_data.size());
184 
185   return error;
186 }
187 
188 Status NativeRegisterContextFreeBSD_arm64::WriteAllRegisterValues(
189     const lldb::DataBufferSP &data_sp) {
190   Status error;
191 
192   if (!data_sp) {
193     error = Status::FromErrorStringWithFormat(
194         "NativeRegisterContextFreeBSD_arm64::%s invalid data_sp provided",
195         __FUNCTION__);
196     return error;
197   }
198 
199   if (data_sp->GetByteSize() != m_reg_data.size()) {
200     error = Status::FromErrorStringWithFormat(
201         "NativeRegisterContextFreeBSD_arm64::%s data_sp contained mismatched "
202         "data size, expected %" PRIu64 ", actual %" PRIu64,
203         __FUNCTION__, m_reg_data.size(), data_sp->GetByteSize());
204     return error;
205   }
206 
207   const uint8_t *src = data_sp->GetBytes();
208   if (src == nullptr) {
209     error = Status::FromErrorStringWithFormat(
210         "NativeRegisterContextFreeBSD_arm64::%s "
211         "DataBuffer::GetBytes() returned a null "
212         "pointer",
213         __FUNCTION__);
214     return error;
215   }
216   ::memcpy(m_reg_data.data(), src, m_reg_data.size());
217 
218   error = WriteRegisterSet(RegisterInfoPOSIX_arm64::GPRegSet);
219   if (error.Fail())
220     return error;
221 
222   return WriteRegisterSet(RegisterInfoPOSIX_arm64::FPRegSet);
223 }
224 
225 llvm::Error NativeRegisterContextFreeBSD_arm64::CopyHardwareWatchpointsFrom(
226     NativeRegisterContextFreeBSD &source) {
227 #ifdef LLDB_HAS_FREEBSD_WATCHPOINT
228   auto &r_source = static_cast<NativeRegisterContextFreeBSD_arm64 &>(source);
229   llvm::Error error = r_source.ReadHardwareDebugInfo();
230   if (error)
231     return error;
232 
233   m_dbreg = r_source.m_dbreg;
234   m_hbp_regs = r_source.m_hbp_regs;
235   m_hwp_regs = r_source.m_hwp_regs;
236   m_max_hbp_supported = r_source.m_max_hbp_supported;
237   m_max_hwp_supported = r_source.m_max_hwp_supported;
238   m_read_dbreg = true;
239 
240   // on FreeBSD this writes both breakpoints and watchpoints
241   return WriteHardwareDebugRegs(eDREGTypeWATCH);
242 #else
243   return llvm::Error::success();
244 #endif
245 }
246 
247 llvm::Error NativeRegisterContextFreeBSD_arm64::ReadHardwareDebugInfo() {
248 #ifdef LLDB_HAS_FREEBSD_WATCHPOINT
249   Log *log = GetLog(POSIXLog::Registers);
250 
251   // we're fully stateful, so no need to reread control registers ever
252   if (m_read_dbreg)
253     return llvm::Error::success();
254 
255   Status res = NativeProcessFreeBSD::PtraceWrapper(PT_GETDBREGS,
256                                                    m_thread.GetID(), &m_dbreg);
257   if (res.Fail())
258     return res.ToError();
259 
260   LLDB_LOG(log, "m_dbreg read: debug_ver={0}, nbkpts={1}, nwtpts={2}",
261            m_dbreg.db_debug_ver, m_dbreg.db_nbkpts, m_dbreg.db_nwtpts);
262   m_max_hbp_supported = m_dbreg.db_nbkpts;
263   m_max_hwp_supported = m_dbreg.db_nwtpts;
264   assert(m_max_hbp_supported <= m_hbp_regs.size());
265   assert(m_max_hwp_supported <= m_hwp_regs.size());
266 
267   m_read_dbreg = true;
268   return llvm::Error::success();
269 #else
270   return llvm::createStringError(
271       llvm::inconvertibleErrorCode(),
272       "Hardware breakpoints/watchpoints require FreeBSD 14.0");
273 #endif
274 }
275 
276 llvm::Error
277 NativeRegisterContextFreeBSD_arm64::WriteHardwareDebugRegs(DREGType) {
278 #ifdef LLDB_HAS_FREEBSD_WATCHPOINT
279   assert(m_read_dbreg && "dbregs must be read before writing them back");
280 
281   // copy data from m_*_regs to m_dbreg before writing it back
282   for (uint32_t i = 0; i < m_max_hbp_supported; i++) {
283     m_dbreg.db_breakregs[i].dbr_addr = m_hbp_regs[i].address;
284     m_dbreg.db_breakregs[i].dbr_ctrl = m_hbp_regs[i].control;
285   }
286   for (uint32_t i = 0; i < m_max_hwp_supported; i++) {
287     m_dbreg.db_watchregs[i].dbw_addr = m_hwp_regs[i].address;
288     m_dbreg.db_watchregs[i].dbw_ctrl = m_hwp_regs[i].control;
289   }
290 
291   return NativeProcessFreeBSD::PtraceWrapper(PT_SETDBREGS, m_thread.GetID(),
292                                              &m_dbreg)
293       .ToError();
294 #else
295   return llvm::createStringError(
296       llvm::inconvertibleErrorCode(),
297       "Hardware breakpoints/watchpoints require FreeBSD 14.0");
298 #endif
299 }
300 
301 #endif // defined (__aarch64__)
302