_gpu_dxg_syncobj_gate.nx

_gpu_dxg_syncobj_gate.nx -- SOVEREIGN-GPU ladder R4g (GPU synchronization-object mechanism on the 5080). SUBMITCOMMAND (0x0f) forwards the command buffer UNINSPECTED to the host -> a real submit needs NVIDIA GPU-ISA command packets (an empty submit would fault/TDR the GPU) = the R5 frontier. The SAFE, real mechanism rung is the GPU sync fabric: create a MONITORED FENCE and round-trip it CPU-side (create -> signal -> wait completes). ABI (size-swept LIVE): CREATESYNCHRONIZATIONOBJECT = 0xC0604710 (size 96; device@0, info.type@8=5 MONITORED_FENCE, union@16: initial@16 / fence_cpu_va@24 OUT / fence_gpu_va@32 OUT; sync_object@88 OUT). SIGNALSYNCHRONIZATIONOBJECTFROMCPU = 0xC0204731 (size 32; device@0, object_count@4, objects@8 ptr, fence_values@16 ptr). WAITFORSYNCHRONIZATIONOBJECTFROMCPU = 0xC028473A (size 40; +async_event@24=0 => synchronous). FINDINGS (honest): the fence_cpu_va page mirrors GPU-engine signals, NOT CPU-side signals (stays 0 here); and SIGNAL-from-CPU is fire-and-forget (doesn't validate the handle locally). So the proof uses what IS verifiable: type-validated create + signal->wait round-trip completion + WAIT/count/fd validation. GREEN iff (author=organ, from REAL device returns): A) chain ok; create MONITORED_FENCE ret==0 AND sync_object != 0 AND fence_cpu_va != 0 (real kernel-mapped page); B) create with an INVALID type (99) is REJECTED (negative) -> the create is type-sensitive, not a blind success; C) signal(so,5)==0 AND signal(so,9)==0 AND sync-wait(so,9)==0 -- the create->signal->wait round-trip COMPLETES (a sync wait for an unreached value would block; it returns, so the signals advanced the real fence to 9); D) TAMPER (validated negatives, so wait isn't a blind return-0): wait(bogus handle) -> neg; signal(object_count=0) -> neg; wait on a non-dxg fd -> -ENOTTY. Marker -> knowledge/status/gpu_dxg.log (DXGSYNCGATE). raw syscalls only. NO-WAVE: sync-object mechanism only; the command-buffer SUBMIT path is NVIDIA GPU-ISA (R5), explicitly out of scope. ZERO compute/throughput. license_tier: ORIGINAL