b22: rollback NOP + S9v3 baked (sp reset)

tools/sbl_uni.py

@@ -236,6 +236,7 @@ def main():
     # immune to [0]-writes that clobber a static maze copy
     from unicorn.arm_const import UC_ARM_REG_PC as _PC
     _nulllog = []
+    _halt_on_null = "--haltonnull" in sys.argv
 
     def hook_null(mu, addr, size, data):
         if len(_nulllog) < 10:
@@ -247,6 +248,8 @@ def main():
                 r, lr, sp = [], -1, -1
             # walk back: find the branch source from hist
             _nulllog.append((count[0], r, lr, sp))
+        if _halt_on_null and len(_nulllog) == 1:
+            return False
         mu.reg_write(_PC, STUB + 1)
 
     mu.hook_add(UC_HOOK_CODE, hook_null, begin=0x0, end=0xFFF)
@@ -313,6 +316,15 @@ def main():
         "ff2c13d940f20004c0f2220440f20005c0f2220540f2000a"
         "c0f6060a41f2000bc0f6060bdff800f081f60208dff800f0"
         "a53b0108"))
+    # S9 stublet (62B @0x08006C48, b22): labyrinth-epilogue exit router.
+    # ldr r3,[sp,#0x14]: nonzero -> original pop.w (legit return);
+    # zero (empty scaffold frames) -> restore r0/r4/r5/sl/fp, reset sp
+    # to 0x085FFF00 (fresh STUBV-fill stack), jump to sbl_main 0x802f69d
+    # via ip (no literal loads).
+    mu.mem_write(0x08006C48, bytes.fromhex(
+        "059b0bb1bde8f081002040f20004c0f2220440f20005c0f2"
+        "220540f2000ac0f6060a41f2000bc0f6060b4ff60073c0f6"
+        "5f039d464ff29d6cc0f6020c6047"))
     # stack zone fill (STUBV odd)
     mu.mem_write(0x085F0000, struct.pack("<I", STUBV) * (0x10000 // 4))
     # pop-site slots (sp values from traces)
@@ -349,7 +361,7 @@ def main():
     # --- end parity ---
     # stub range is readonly on HW/QEMU: ignore SBL heap-clobber writes,
     # keep maze/stublets intact (restore-on-write with reentrancy guard)
-    STUB_LO, STUB_HI = 0x080068C0, 0x08006C50  # +S7 + banner tail
+    STUB_LO, STUB_HI = 0x080068C0, 0x08006C90  # +S7/S9 + banner tail
     stub_snap = bytes(mu.mem_read(STUB_LO, STUB_HI - STUB_LO))
     _inww = [False]
     _swn = [0]
@@ -461,8 +473,10 @@ def main():
         print("hist:", [hex(pc) for pc, _ in list(hist)[-12:]])
     if elog is not None:
         print(f"entries: {len(elog)}")
-        for n, prev, cur in elog[-30:]:
-            print(f"  insn#{n} {prev:#x} -> {cur:#x}")
+        for n, prev, cur in elog[:10]:
+            print(f"  FIRST insn#{n} {prev:#x} -> {cur:#x}")
+        for n, prev, cur in elog[-10:]:
+            print(f"  LAST insn#{n} {prev:#x} -> {cur:#x}")
     if _splog is not None:
         print(f"sp-highs: {len(_splog)}")
         for n, pc, sp in _splog: