Implementation sources

Exceptions & traps

The arm64 exception path, the Mach trap and BSD syscall dispatch tables, and the register and saved-state accessors behind them.

Exception vectors and first-level handlersosfmk/arm64/locore.s

Second-level exception handlersosfmk/arm64/sleh.c

Kernel entry and CPU bring-uposfmk/arm64/start.s

Mach trap tableosfmk/kern/syscall_sw.c

BSD system call dispatch (arm)bsd/dev/arm/systemcalls.c

Mach exception deliveryosfmk/kern/exception.c

Processor and exception-syndrome registers (arm64)osfmk/arm64/proc_reg.h

Saved-state (exception frame) accessorsosfmk/mach/arm/thread_status.h

Exception delivery structuresosfmk/kern/exception.h

Thread and thread_ro structuresosfmk/kern/thread.h

Debugging

Panic, the in-kernel debugger, and the Kernel Debug Protocol (KDP) used by remote debuggers and core dumps.

Kernel debugging and panic APIosfmk/kern/debug.h

Panic and debugger entryosfmk/kern/debug.c

Kernel Debug Protocol (KDP)osfmk/kdp/kdp.c

Kernel core dumpsosfmk/kdp/kdp_core.h

Task-port authorization, task and thread suspension, exception-port ownership, arm64 debug state, and executable-memory updates. These implementation references use the pinned XNU checkout; current SDK declarations remain in the API reference.

Task-port access and authorizationbsd/kern/kern_proc.c

Task suspension, resume tokens, and thread enumerationosfmk/kern/task.c

Thread suspension, aborts, and state accessosfmk/kern/thread_act.c

Exception-port registration and restorationosfmk/kern/ipc_tt.c

arm64 register and debug-state accessosfmk/arm64/status.c

arm64 debug-register installationosfmk/arm64/pcb.c

Debugger memory operations and cache attributesosfmk/vm/vm_user.c

VM protection, code writes, and target cache traversalosfmk/vm/vm_map.c

Physical-page instruction-cache synchronizationosfmk/arm/pmap/pmap.c

IPC rights and reply-port copyin checksosfmk/ipc/ipc_right.c

MIG (Mach Interface Generator)

The migcom compiler (from Apple’s bootstrap_cmds) that turns .defs interface files into the C stubs and Request/Reply message structs behind the Mach routines — the code generating what you see on the header pages.

MIG compiler driverbootstrap_cmds/migcom.tproj/mig.c

MIG codegen: header (.h)bootstrap_cmds/migcom.tproj/header.c

MIG codegen: user stubsbootstrap_cmds/migcom.tproj/user.c

MIG codegen: server demuxbootstrap_cmds/migcom.tproj/server.c

MIG routine modelbootstrap_cmds/migcom.tproj/routine.c

MIG type marshalingbootstrap_cmds/migcom.tproj/type.c

LLDB debugserver

Apple’s user-space debugger server implementation: acquiring a task port, installing and restoring exception ports, coordinating task and thread suspension, writing executable memory, and arm64 hardware single stepping.

debugserver task control and exception threadllvm-project/lldb/tools/debugserver/source/MacOSX/MachTask.mm

debugserver Mach exception messages and saved portsllvm-project/lldb/tools/debugserver/source/MacOSX/MachException.cpp

debugserver process launch, attach, stop, and resumellvm-project/lldb/tools/debugserver/source/MacOSX/MachProcess.mm

debugserver per-thread suspension and resume preparationllvm-project/lldb/tools/debugserver/source/MacOSX/MachThread.cpp

debugserver all-stop thread coordinationllvm-project/lldb/tools/debugserver/source/MacOSX/MachThreadList.cpp

debugserver memory writes and instruction-cache flushesllvm-project/lldb/tools/debugserver/source/MacOSX/MachVMMemory.cpp

debugserver arm64 single-step statellvm-project/lldb/tools/debugserver/source/MacOSX/arm64/DNBArchImplARM64.cpp

Register spotlights

The x18 registerevery use of it in the hosted sources

Debugging references

GNU Mach kernel debugger (ddb)the built-in interactive kernel debugger — commands, variables, expressions