saimaa: BKPT in exception vectors for fault capture

qemu/saimaa.c

@@ -113,6 +113,11 @@ static uint64_t saimaa_vec_read(void *opaque, hwaddr off, unsigned size)
                 (unsigned)off, (unsigned long)pc - (th ? 4 : 8));
         saimaa_vec_n++;
     }
+    /* BKPT at exception vectors: data/prefetch abort fetch traps to gdb */
+    if (off == 0x8 || off == 0xC || off == 0x10 || off == 0x18 ||
+        off == 0x1C) {
+        return 0xE1200070;
+    }
     return 0;
 }