StarletBootstrapProbe: report StarOS's panic words

StarOS's panic path (ADR-0014 R6) writes no trace line: it sets the guard
word __panic_state, stores __panic_code and halts. LoadBootstrapELF now
returns both symbols when an image has them (optional, but both or
neither, as words of the data segment), and the probe stops a run whose
guard is set: it prints the trace published so far and
"Starlet panic state <n> code <n>", and passes --expect-panic when the
state is 1. Images without these symbols (StarletOS) load and run as
before; a REV:PANIC trace line still satisfies --expect-panic.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Source/Core/Core/IOS/Starlet/BootstrapELF.cpp

@@ -192,6 +192,14 @@ bool LoadBootstrapELF(std::span<const u8> image, ARMBus& bus, BootstrapELFInfo*
         parsed.fault_spsr = address;
         found_fault_spsr = true;
       }
+      else if (*name == "__panic_state")
+      {
+        parsed.panic_state = address;
+      }
+      else if (*name == "__panic_code")
+      {
+        parsed.panic_code = address;
+      }
     }
   }
   const auto data_segment =
@@ -208,6 +216,12 @@ bool LoadBootstrapELF(std::span<const u8> image, ARMBus& bus, BootstrapELFInfo*
   {
     return Fail(error, "bootstrap ELF is missing the trace or fault symbols");
   }
+  // The panic words are optional, but both or neither, as words of the data segment.
+  if ((parsed.panic_state != 0) != (parsed.panic_code != 0) ||
+      (parsed.panic_state != 0 && (!in_data(parsed.panic_state, 4) || !in_data(parsed.panic_code, 4))))
+  {
+    return Fail(error, "bootstrap ELF has an invalid panic symbol");
+  }
 
   for (const Segment& segment : segments)
   {

Source/Core/Core/IOS/Starlet/BootstrapELF.h

@@ -19,6 +19,10 @@ struct BootstrapELFInfo
   u32 fault_code = 0;
   u32 fault_lr = 0;
   u32 fault_spsr = 0;
+  // Optional (StarOS ADR-0014 R6): the panic path's guard and code words, 0 when the image has
+  // none. A nonzero guard means the panic handler ran.
+  u32 panic_state = 0;
+  u32 panic_code = 0;
 };
 
 // Load the Phase 01 ELF into a bus already configured with the high SRAM mapping.