S12v5: r7 restore in-stub

tools/sbl_uni.py

@@ -104,6 +104,13 @@ def main():
     calls = [] if "--calltrace" in sys.argv else None
     rets = [] if "--retrace" in sys.argv else None
     qlog = [] if "--querylog" in sys.argv else None
+    # frozen-maze breaker: maze entries with identical lr and no bl
+    # between them mean a zero-state-change spin (maze->mid-fn->maze).
+    # After K, redirect once to poll resumption (fresh bls unfreeze lr).
+    _fmlr = [None]
+    _fmct = [0]
+    _FMK = 50
+    _FMPC = 0x8007779
     _traps = []
     _trap_n = [0]
     if "--trap" in sys.argv:
@@ -127,6 +134,25 @@ def main():
     def hook_code(mu, addr, size, data):
         count[0] += 1
         last[0] = addr
+        if 0x08006B8C <= addr < 0x08006B9E:
+            try:
+                _lr = mu.reg_read(_LR)
+            except Exception:
+                _lr = None
+            if _lr == _fmlr[0]:
+                _fmct[0] += 1
+                if _fmct[0] >= _FMK:
+                    _fmct[0] = 0
+                    _fmlr[0] = None
+                    mu.reg_write(_PC, _FMPC)
+                    return
+            else:
+                _fmlr[0] = _lr
+                _fmct[0] = 0
+        elif _fmlr[0] is not None:
+            # any non-maze fetch: reset only on bl (lr change means
+            # fresh calls; other insns keep the freeze assessment)
+            pass
         if _splog is not None:
             try:
                 sp = mu.reg_read(UC_ARM_REG_SP)
@@ -385,16 +411,17 @@ def main():
     # to the dispatcher via stale lr (TZ bringup deferred).
     # NOTE: overwrites 4B of real ARM trampoline (recoverable from ELF).
     mu.mem_write(0x00221EF8, bytes([0x00, 0x20, 0x70, 0x47]))
-    # S12-stub (b27, 84B @0x08006964, ARM): blx-to-padding becomes
+    # S12-stub (b27, 92B @0x08006964, ARM): blx-to-padding becomes
     # smart dispatcher: ldr ip,[sp,#4] (=pushed lr); ip==STUBV/even/
     # non-code => ip=poll resumption 0x8007779; else keep pushed-lr;
-    # then ACK peripheral bit1 ([literal 0x073A100]); bx lr.
-    # PBL would place the real ARM helper here.
+    # restore r7 (peripheral base, S16 dormant); ACK peripheral bit1
+    # ([literal 0x073A100]); bx lr. PBL would place the real helper.
     mu.mem_write(0x08006964, bytes.fromhex(
         "04c09de58d3b06e3003840e303005ce10700000a0100"
         "1ce30500000a2c3ca0e1080053e30400000a2c3ea0e1"
-        "080053e30100000a79c707e300c840e30c309fe50020"
-        "93e5022082e3002083e51eff2fe100a17300"))
+        "080053e30100000a79c707e300c840e300700ae37370"
+        "40e30c309fe5002093e5022082e3002083e51eff2fe1"
+        "00a17300"))
     # S16-stublet (b27, 64B @0x08006CC0): smart return for B66 bx ip.
     # ip==STUBV (fill/maze, never a legit return) => default;
     # ip odd + top 8 (code) => add sp,#8 (pop the helper frame B66