health record support

tutorials/stm32/nucleo-h723zg/cubemx/Core/Src/main.c

@@ -133,7 +133,7 @@ int main(void)
 
   /* Initialize all configured peripherals */
   MX_GPIO_Init();
-  (void) MX_ETH_Init;  // Don't use that stuff, Mongoose handle Ethernet
+  MX_ETH_Init();
   MX_RNG_Init();
   MX_USART3_UART_Init();
   /* USER CODE BEGIN 2 */

tutorials/stm32/nucleo-h723zg/minimal/Makefile

@@ -1,24 +1,22 @@
 # Copyright (c) 2026 Cesanta Software Limited
 # Environment setup: https://mongoose.ws/docs/getting-started/build-environment/
 
+MGDIR = ../../../..
+
 CFLAGS  = -W -Wall -Wextra -Wundef -Wshadow -Wdouble-promotion
 CFLAGS += -Wformat-truncation -fno-common -Wconversion -Wno-sign-conversion
 CFLAGS += -g3 -Os -ffunction-sections -fdata-sections
-CFLAGS += -I. -Icmsis_core/CMSIS/Core/Include -Icmsis_h7/Include -Imongoose
+CFLAGS += -I. -I$(MGDIR) -Icmsis_core/CMSIS/Core/Include -Icmsis_h7/Include
 CFLAGS += -mcpu=cortex-m7 -mthumb -mfloat-abi=hard -mfpu=fpv5-d16 $(CFLAGS_EXTRA)
 LDFLAGS ?= -Tlink.ld -nostdlib -nostartfiles --specs nosys.specs -lc -lgcc -Wl,--gc-sections -Wl,-Map=$@.map
 
 SOURCES = main.c hal.c
 SOURCES += cmsis_h7/Source/Templates/gcc/startup_stm32h723xx.s
-SOURCES += mongoose/mongoose.c
-
+SOURCES += $(MGDIR)/mongoose.c
 
 all build example: firmware.bin
 
-mongoose/mongoose.c mongoose/mongoose.h:
-	cp ../../../../mongoose.[ch] mongoose/
-
-firmware.elf: cmsis_core cmsis_h7 hal.h link.ld Makefile $(SOURCES) mongoose/mongoose.h
+firmware.elf: cmsis_core cmsis_h7 hal.h link.ld Makefile $(SOURCES) $(MGDIR)/mongoose.h mongoose_config.h
 	arm-none-eabi-gcc $(SOURCES) $(CFLAGS) $(CFLAGS_EXTRA) $(LDFLAGS) -o $@
 
 firmware.bin: firmware.elf
@@ -36,7 +34,7 @@ cmsis_h7:
 	git clone -q -c advice.detachedHead=false --depth 1 -b v1.10.6 https://github.com/STMicroelectronics/cmsis_device_h7 $@
 
 clean:
-	rm -rf firmware.* cmsis_* mongoose/mongoose.*
+	rm -rf firmware.* cmsis_*
 
 
 # Automated remote test. Requires env variable VCON_API_KEY set. See https://vcon.io/automated-firmware-tests/

tutorials/stm32/nucleo-h723zg/minimal/link.ld

@@ -23,6 +23,10 @@ SECTIONS {
 
   .eth_ram : { *(.eth_ram .eth_ram*) } > ram_d1 AT > flash
 
+  /* Health record. NOLOAD and in unused DTCM, so startup code neither copies
+     nor zeroes it and the contents survive a warm reset */
+  .mg_health (NOLOAD) : { KEEP(*(.mg_health .mg_health*)) } > dtcmram
+
   . = ALIGN(8);
   _end = .;
 }

tutorials/stm32/nucleo-h723zg/minimal/main.c

@@ -24,10 +24,54 @@ static void log_fn(char ch, void *param) {
 static void blink_task(void) {
   static uint64_t blink_timer = 0;
   if (hal_timer_expired(&blink_timer, 500, hal_get_tick())) {
-    hal_gpio_toggle(LED1);
+    hal_gpio_toggle(LED2);
   }
 }
 
+// Fault handler body. Runs in exception context: no printf, no malloc, no
+// blocking calls. Records the crash reason and a backtrace into the health
+// record, then resets.
+// "used" keeps the linker from garbage-collecting this section: the only
+// reference is the "b fault_c" branch in the naked handler below
+__attribute__((used, noinline)) static void fault_c(uint32_t *sp) {
+  extern uint8_t _estack;  // End of the main RAM region, defined in link.ld
+  size_t n = 0;
+  mg_health_record.reset_reason = MG_HEALTH_RESET_FAULT;
+  // Frame 0 is the faulting PC, frame 1 the caller's LR. Deeper frames come
+  // from a heuristic stack walk: BL pushes an odd return address that lives
+  // in flash. A stack word that merely looks like an address shows up as a
+  // bogus frame when symbolised, which is easy to filter by eye
+  mg_health_record.backtrace[n++] = sp[6] & ~1U;  // Stacked PC
+  mg_health_record.backtrace[n++] = sp[5] & ~1U;  // Stacked LR
+  for (uint32_t *p = sp + 8;
+       n < MG_HEALTH_BACKTRACE &&
+       (uintptr_t) p < (uintptr_t) sp + 4096U &&   // Bound the scan
+       (uintptr_t) p < (uintptr_t) &_estack;       // Stay in RAM
+       p++) {
+    uint32_t v = *p;
+    if ((v & 1U) && v >= 0x08000000U && v < 0x08000000U + 1024U * 1024U) {
+      mg_health_record.backtrace[n++] = v & ~1U;
+    }
+  }
+  NVIC_SystemReset();
+}
+
+// Common fault entry. EXC_RETURN bit 2 tells which stack was in use:
+// 0 = MSP, 1 = PSP. Load the faulting SP into r0 and hand it to fault_c()
+__attribute__((naked)) void HardFault_Handler(void) {
+  __asm volatile(
+      "tst lr, #4\n\t"   // Test EXC_RETURN bit 2
+      "ite eq\n\t"       // If zero, use MSP; else PSP
+      "mrseq r0, msp\n\t"
+      "mrsne r0, psp\n\t"
+      "b fault_c\n\t");
+}
+
+// Route the other fault types through the same entry point
+void MemManage_Handler(void) __attribute__((alias("HardFault_Handler")));
+void BusFault_Handler(void) __attribute__((alias("HardFault_Handler")));
+void UsageFault_Handler(void) __attribute__((alias("HardFault_Handler")));
+
 uint64_t mg_millis(void) {
   return hal_get_tick();
 }
@@ -70,6 +114,15 @@ static void http_ev_handler(struct mg_connection *c, int ev, void *ev_data) {
 
 int main(void) {
   hal_clock_init();
+
+  // Enable MemManage, BusFault and UsageFault so faults are precise and
+  // routed to their own handlers instead of escalating to HardFault
+  SCB->SHCSR |= SCB_SHCSR_MEMFAULTENA_Msk | SCB_SHCSR_BUSFAULTENA_Msk |
+                SCB_SHCSR_USGFAULTENA_Msk;
+
+  MG_OTA_BOOT_CHECK();  // Must be called after clock init
+  MG_HEALTH_INIT();     // Must be called after clock init
+
   hal_uart_init(UART_DEBUG, UART_DEBUG_TX_PIN, UART_DEBUG_RX_PIN, 115200);
   mg_log_set_fn(log_fn, UART_DEBUG);
   hal_rng_init();
@@ -79,8 +132,17 @@ int main(void) {
   hal_gpio_output(LED3);
 
   MG_INFO(("Initialised. CPU clock: %lu MHz", SystemCoreClock / 1000000));
-
-  MG_OTA_BOOT_CHECK();  // Must be called after clock init
+  // Report the previous boot's crash backtrace, if any
+  if (mg_health_reason() == MG_HEALTH_RESET_FAULT) {
+    MG_INFO(("Previous boot faulted. Backtrace:"));
+    for (int i = 0; i < MG_HEALTH_BACKTRACE; i++) {
+      if (mg_health_record.backtrace[i] == 0) break;
+      MG_INFO(("  #%d 0x%08lx", i,
+               (unsigned long) mg_health_record.backtrace[i]));
+    }
+    // * (volatile uint32_t *) 0 = 123;  // Deliberate fault: write to unmapped memory
+  }
+  // for (;;) (void) 0;
 
   struct mg_mgr mgr;
   mg_mgr_init(&mgr);

tutorials/stm32/nucleo-h723zg/minimal/mongoose_config.h

@@ -44,6 +44,16 @@
 #define MG_OTA_STATE_GET()    (RTC->BKP0R)
 #define MG_OTA_STATE_SET(v)   (RTC->BKP0R = (uint32_t) (v))
 
+// Health record lives in the .mg_health region, see link.ld
+#define MG_HEALTH_RAM __attribute__((section(".mg_health")))
+
+// mdash device token
+#define MG_ENABLE_MDASH 1
+
+#ifndef MG_MDASH_KEY
+#define MG_MDASH_KEY ""  // Set this
+#endif
+
 // Construct MAC address from the MCU unique ID
 #define MGUID ((uint32_t *) UID_BASE)
 #define MG_SET_MAC_ADDRESS(mac)      \