gsp-phys: freeze-safe release, boot-proof READY, and guest-wiring P2/P3/P5-wave1

Host-freeze fix bundle (validated 2/2 supervised cycles):
- power unlock now latches D0/D3cold by default (new gsp_phys_repower,
  default 0); releasing the claim can no longer power-gate the board and
  hard-freeze the host on resume
- bounded post-rebind readiness gate before dropping the locks; bounded D0
  settle/verify before the unbind
- READY means a live GSP-RM session: the async worker and the module-owned
  join only expose READY when init-done is seen and no unload was sent;
  otherwise the claim is released fail-open
- FWSEC reads DMEM0/IMEM back before STARTCPU and fails fast when the
  staging is not visible
- the claim harness leaves the board latched by default and takes
  --restore-power to opt back into the old restore

Guest-wiring:
- P2: generation-keyed fn65 static-config snapshot cache plus a default-off
  identity overlay (new gsp_phys_static_live) for name/short-name/VBIOS;
  the probe cycle runs once per backend generation at READY
- P3: default-off read-only RM_CONTROL forwarding whitelist (new
  gsp_phys_ctrl_forward) with emulated-handle translation to the adopted
  server handles and full emulation fallback
- P5 wave 1: default-off shadow execution of guest CE pushes on the ladder
  channel (new gsp_phys_work_forward) via a dedicated ordered work item;
  the ladder stage-4 submission is refactored into a shared bounded helper
  and the software release path stays authoritative

Live: module-owned boot to init-done, guest smoke ALL OK 64/64 with P2/P3
enabled, 514 shadow copies observed on the physical CE; all cycles released
cleanly with WPR2 down and no reboot.

1 files changed, 11 insertions, 0 deletions

diff --git a/kernel/gsp_sema_service.h b/kernel/gsp_sema_service.h
index 7778443..ae9b7da 100644
--- a/kernel/gsp_sema_service.h
+++ b/kernel/gsp_sema_service.h
@@ -66,6 +66,17 @@ int  gsp_sema_service_counter_add(u32 h_object, u64 pa);
 void gsp_sema_service_doorbell(u32 token);
 
 /*
+ * P5 wave-1 shadow work lifetime hooks. The backend release path must call
+ * gsp_sema_service_work_quiesce() before it frees the ladder buffers: it
+ * pauses new shadow requests and waits (bounded by the submit's 200 ms poll
+ * cap) for the in-flight one to finish, so no poll ever touches freed memory.
+ * gsp_sema_service_work_resume() re-enables requests when a new backend
+ * session starts.
+ */
+void gsp_sema_service_work_quiesce(void);
+void gsp_sema_service_work_resume(void);
+
+/*
  * Discover and pin GR (compute) channel rings after the CE region of the
  * channel video-memory allocation. Set false to leave GR rings untranslated
  * (the pump then only runs the CE channels).