Fix VFS pre-RTOS mutex fallback, revert timeouts, improve CI test

- lib/dmvfs/src/dmvfs.c: lock_mutex() now falls back to Dmod_EnterCritical()
  when Dmod_Mutex_Lock fails (e.g. before vTaskStartScheduler). unlock_mutex()
  is symmetric: calls Dmod_ExitCritical() when Dmod_Mutex_Unlock fails.
  This ensures filesystem mounts (mount_embedded_filesystems) always succeed
  regardless of RTOS state, allowing board modules (dmgpio, dmclk, etc.) to
  load and configure via dmell/dmdevfs.

- scripts/run_renode_tests.sh: revert CONNECT_TIMEOUT 120->90 and
  MONITOR_TIMEOUT 60->30 (original values are sufficient with proper fix).

- scripts/verify_renode_logs.sh: add support for lines starting with '!'
  meaning the pattern must NOT appear in the firmware log.

- configs/renode/expected_logs.txt: add !HardFault_Handler invoked! as a
  crash guard (negative check placed at top); add explanatory comments for
  the boot sequence and pattern syntax.

Co-authored-by: JohnAmadis <17320783+JohnAmadis@users.noreply.github.com>

Author: Copilot

configs/renode/expected_logs.txt

@@ -7,12 +7,23 @@
 # .dmod.outputs sections, leading to an immediate hard-fault whenever a
 # loaded driver (e.g. dmgpio via dmdevfs) tried to log a message.
 #
-# All lines below must appear in the monitor-gdb output.  If the firmware
-# crashes before completing initialization, none of the later lines will
-# appear and the test will fail.
+# With the fix applied the boot sequence is:
+#   1. Heap initialised
+#   2. modules.dmp loaded, dmell enabled
+#   3. Filesystems mounted (/configs, /dev)  -- requires the dmvfs pre-RTOS
+#      mutex fallback fix so that mounts succeed before vTaskStartScheduler
+#   4. FreeRTOS scheduler starts
+#   5. dmell loads and configures board drivers (dmgpio, dmclk, etc.)
+#      -- this is where the hard-fault used to occur with the corrupt
+#         .dmod.inputs linker bug
 #
-# Each line is a literal substring to match in the log (grep -q).
-# Lines starting with # and empty lines are ignored.
+# Lines starting with ! must NOT appear in the log (crash guard).
+# The pattern matched is everything after the leading '!'.
+# All other non-empty, non-comment lines must appear in the log.
 
+# --- crash guard: a hard-fault means something is still broken ---
+!HardFault_Handler invoked!
+
+# --- positive checks: firmware must reach these milestones ---
 Heap initialized
 DMOD-Boot started

scripts/run_renode_tests.sh

@@ -41,8 +41,8 @@ EXPECTED_LOGS="$SOURCE_DIR/configs/renode/expected_logs.txt"
 VERIFY_SCRIPT="$SOURCE_DIR/scripts/verify_renode_logs.sh"
 
 # Timeouts (seconds)
-CONNECT_TIMEOUT=120
-MONITOR_TIMEOUT=60
+CONNECT_TIMEOUT=90
+MONITOR_TIMEOUT=30
 
 echo "=============================================="
 echo " dmod-boot Renode emulation tests"

scripts/verify_renode_logs.sh

@@ -1,6 +1,14 @@
 #!/bin/bash
 # Verify that expected log messages appear in Renode firmware execution
 # Usage: verify_renode_logs.sh <log_file> <expected_logs_file>
+#
+# Lines in the expected_logs_file:
+#   - Empty lines and lines starting with # are ignored.
+#   - Lines starting with ! are "must NOT appear" patterns; the pattern
+#     being checked is the text after the leading '!'.
+#     Example: !HardFault_Handler invoked!
+#             (checks that the text "HardFault_Handler invoked!" is absent)
+#   - All other lines are "must appear" patterns.
 
 set -e
 
@@ -33,13 +41,25 @@ while IFS= read -r expected_log || [ -n "$expected_log" ]; do
     if [ -z "$expected_log" ] || [[ "$expected_log" =~ ^#.* ]]; then
         continue
     fi
-    
-    echo -n "Checking for: '$expected_log' ... "
-    if grep -q "$expected_log" "$LOG_FILE"; then
-        echo "✓ FOUND"
+
+    # Lines starting with ! are "must NOT appear" patterns
+    if [[ "$expected_log" =~ ^!.* ]]; then
+        pattern="${expected_log:1}"
+        echo -n "Checking absent: '$pattern' ... "
+        if grep -q "$pattern" "$LOG_FILE"; then
+            echo "✗ FOUND (should be absent)"
+            ALL_FOUND=false
+        else
+            echo "✓ ABSENT"
+        fi
     else
-        echo "✗ NOT FOUND"
-        ALL_FOUND=false
+        echo -n "Checking for: '$expected_log' ... "
+        if grep -q "$expected_log" "$LOG_FILE"; then
+            echo "✓ FOUND"
+        else
+            echo "✗ NOT FOUND"
+            ALL_FOUND=false
+        fi
     fi
 done < "$EXPECTED_LOGS_FILE"