Mach messages: restartable

Message catalog and dispatch · All subsystem ranges · Kernel entry map

osfmk/mach/restartable.defs. Listed in the kernel kobject subsystem table, subject to the registration guards and per-slot skips. The destination's typed capability still controls admission. Registration evidence: mig_e.

Reading these entries

IDs are computed from the explicit preprocessing profiles in the catalog guide, counting both routines and skip slots. They are not discovered from a running kernel. Each entry retains all observed names/declaration locations; the displayed fields come from the first non-skipped profile. Alternative declarations can have different fields. simpleroutine is one-way at the MIG interface level.

An interface contract block quotes the adjacent local .defs comment with whitespace normalized. Mechanism paragraphs explain selected implementation decisions. Local body links and call names identify implementation evidence; syntactic call lists are reading aids, not a proof that every listed call executes on every path. Short complete implementation bodies are included where especially useful.

Complete routine and reserved-slot catalog

8000: task_restartable_ranges_register

Validate and register restartable instruction ranges for the current eligible task.

Mechanism: Only the current task may register. Validation precedes the task lock; translated tasks are rejected when Rosetta is configured. Installation requires a single-threaded task, and release kernels also reject replacing an existing registration. The creator installs the validated range representation while task creation is serialized by the task lock; failures leave the old registration intact. task_restartable_ranges_register.

Declarations: task_restartable_ranges_register (server64, server32, client64, client32, libsyscall64, sender64, local64).

Fields after preprocessing (server64):

routine task_restartable_ranges_register(
  target_task : task_t;
  ranges : task_restartable_range_array_t);

Local body: task_restartable_ranges_register. Calls visible in this body include current_task, task_is_translated, _ranges_validate, task_lock, _restartable_ranges_create, task_unlock.

8001: task_restartable_ranges_synchronize

Request synchronization across the task's threads, using reset-PC AST/IPI acknowledgement where needed.

Mechanism: Only the current task is accepted; no registered ranges is a successful no-op. A priority floor bounds scheduler interference while the task lock serializes synchronization, with concurrent callers rejected as already waiting. A release fence precedes posting RESET_PCS ASTs to other threads. The caller waits for required acknowledgments/fault resolution, restarts enumeration after lock-dropping waits, then clears the in-flight flag and releases its priority floor. task_restartable_ranges_synchronize.

Declarations: task_restartable_ranges_synchronize (server64, server32, client64, client32, libsyscall64, sender64, local64).

Fields after preprocessing (server64):

routine task_restartable_ranges_synchronize(
  target_task : task_t);

Local body: task_restartable_ranges_synchronize. Calls visible in this body include current_task, thread_priority_floor_start, task_lock, os_atomic_thread_fence, queue_iterate, current_thread, act_set_ast_reset_pcs, thread_rr_wait_if_needed, task_unlock, thread_priority_floor_end.