1 //===-- ThreadMachCore.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 "ThreadMachCore.h"
10 
11 #include "lldb/Breakpoint/Watchpoint.h"
12 #include "lldb/Host/SafeMachO.h"
13 #include "lldb/Symbol/ObjectFile.h"
14 #include "lldb/Target/AppleArm64ExceptionClass.h"
15 #include "lldb/Target/Process.h"
16 #include "lldb/Target/RegisterContext.h"
17 #include "lldb/Target/StopInfo.h"
18 #include "lldb/Target/Target.h"
19 #include "lldb/Target/Unwind.h"
20 #include "lldb/Utility/ArchSpec.h"
21 #include "lldb/Utility/DataExtractor.h"
22 #include "lldb/Utility/RegisterValue.h"
23 #include "lldb/Utility/State.h"
24 #include "lldb/Utility/StreamString.h"
25 
26 #include "ProcessMachCore.h"
27 //#include "RegisterContextKDP_arm.h"
28 //#include "RegisterContextKDP_i386.h"
29 //#include "RegisterContextKDP_x86_64.h"
30 
31 using namespace lldb;
32 using namespace lldb_private;
33 
34 // Thread Registers
35 
36 ThreadMachCore::ThreadMachCore(Process &process, lldb::tid_t tid)
37     : Thread(process, tid), m_thread_name(), m_dispatch_queue_name(),
38       m_thread_dispatch_qaddr(LLDB_INVALID_ADDRESS), m_thread_reg_ctx_sp() {}
39 
40 ThreadMachCore::~ThreadMachCore() { DestroyThread(); }
41 
42 const char *ThreadMachCore::GetName() {
43   if (m_thread_name.empty())
44     return nullptr;
45   return m_thread_name.c_str();
46 }
47 
48 void ThreadMachCore::RefreshStateAfterStop() {
49   // Invalidate all registers in our register context. We don't set "force" to
50   // true because the stop reply packet might have had some register values
51   // that were expedited and these will already be copied into the register
52   // context by the time this function gets called. The KDPRegisterContext
53   // class has been made smart enough to detect when it needs to invalidate
54   // which registers are valid by putting hooks in the register read and
55   // register supply functions where they check the process stop ID and do the
56   // right thing.
57   const bool force = false;
58   GetRegisterContext()->InvalidateIfNeeded(force);
59 }
60 
61 bool ThreadMachCore::ThreadIDIsValid(lldb::tid_t thread) { return thread != 0; }
62 
63 lldb::RegisterContextSP ThreadMachCore::GetRegisterContext() {
64   if (!m_reg_context_sp)
65     m_reg_context_sp = CreateRegisterContextForFrame(nullptr);
66   return m_reg_context_sp;
67 }
68 
69 lldb::RegisterContextSP
70 ThreadMachCore::CreateRegisterContextForFrame(StackFrame *frame) {
71   lldb::RegisterContextSP reg_ctx_sp;
72   uint32_t concrete_frame_idx = 0;
73 
74   if (frame)
75     concrete_frame_idx = frame->GetConcreteFrameIndex();
76 
77   if (concrete_frame_idx == 0) {
78     if (!m_thread_reg_ctx_sp) {
79       ProcessSP process_sp(GetProcess());
80 
81       ObjectFile *core_objfile =
82           static_cast<ProcessMachCore *>(process_sp.get())->GetCoreObjectFile();
83       if (core_objfile)
84         m_thread_reg_ctx_sp =
85             core_objfile->GetThreadContextAtIndex(GetID(), *this);
86     }
87     reg_ctx_sp = m_thread_reg_ctx_sp;
88   } else {
89     reg_ctx_sp = GetUnwinder().CreateRegisterContextForFrame(frame);
90   }
91   return reg_ctx_sp;
92 }
93 
94 static bool IsCrashExceptionClass(AppleArm64ExceptionClass EC) {
95   switch (EC) {
96   case AppleArm64ExceptionClass::ESR_EC_UNCATEGORIZED:
97   case AppleArm64ExceptionClass::ESR_EC_SVC_32:
98   case AppleArm64ExceptionClass::ESR_EC_SVC_64:
99     // In the ARM exception model, a process takes an exception when asking the
100     // kernel to service a system call. Don't treat this like a crash.
101     return false;
102   default:
103     return true;
104   }
105 }
106 
107 bool ThreadMachCore::CalculateStopInfo() {
108   ProcessSP process_sp(GetProcess());
109   if (process_sp) {
110     StopInfoSP stop_info;
111     RegisterContextSP reg_ctx_sp = GetRegisterContext();
112 
113     if (reg_ctx_sp) {
114       Target &target = process_sp->GetTarget();
115       const ArchSpec arch_spec = target.GetArchitecture();
116       const uint32_t cputype = arch_spec.GetMachOCPUType();
117 
118       if (cputype == llvm::MachO::CPU_TYPE_ARM64 ||
119           cputype == llvm::MachO::CPU_TYPE_ARM64_32) {
120         const RegisterInfo *esr_info = reg_ctx_sp->GetRegisterInfoByName("esr");
121         const RegisterInfo *far_info = reg_ctx_sp->GetRegisterInfoByName("far");
122         RegisterValue esr, far;
123         if (reg_ctx_sp->ReadRegister(esr_info, esr) &&
124             reg_ctx_sp->ReadRegister(far_info, far)) {
125           const uint32_t esr_val = esr.GetAsUInt32();
126           const AppleArm64ExceptionClass exception_class =
127               getAppleArm64ExceptionClass(esr_val);
128           if (IsCrashExceptionClass(exception_class)) {
129             StreamString S;
130             S.Printf("%s (fault address: 0x%" PRIx64 ")",
131                      toString(exception_class), far.GetAsUInt64());
132             stop_info =
133                 StopInfo::CreateStopReasonWithException(*this, S.GetData());
134           }
135         }
136       }
137     }
138 
139     // Set a stop reason for crashing threads only so that they get selected
140     // preferentially.
141     if (stop_info)
142       SetStopInfo(stop_info);
143     return true;
144   }
145   return false;
146 }
147