arm: Added breakpoint in stack overflow trap.

arch/arm/src/armv7-m/Kconfig

@@ -116,6 +116,16 @@ config ARMV7M_STACKCHECK
 		CFLAGS when you compile. This addition to your CFLAGS should probably
 		be added to the definition of the CFFLAGS in your board Make.defs file.
 
+config ARMV7M_STACKCHECK_BREAKPOINT
+	bool "Breakpoint on stack overflow"
+	default n
+	depends on ARMV7M_STACKCHECK
+	---help---
+		If enabled, a hard-coded breakpoint will be inserted to the stack
+		overflow trap. This is useful to stop the execution of the program
+		and diagnose the issue before the hardfault handler is called (and
+		context information is lost).
+
 config ARMV7M_ITMSYSLOG
 	bool "ITM SYSLOG support"
 	default n

arch/arm/src/armv7-m/arm_stackcheck.c

@@ -69,6 +69,14 @@ void __stack_overflow_trap(void)
 
   uint32_t regval;
 
+#ifdef CONFIG_ARMV7M_STACKCHECK_BREAKPOINT
+  regval = getreg32(NVIC_DHCSR);
+  if (regval & NVIC_DHCSR_C_DEBUGEN)
+    {
+      __asm("bkpt 1");
+    }
+#endif
+
   /* force hard fault */
 
   regval  = getreg32(NVIC_INTCTRL);

arch/arm/src/armv8-m/Kconfig

@@ -115,6 +115,16 @@ config ARMV8M_STACKCHECK_HARDWARE
 
 endchoice
 
+config ARMV8M_STACKCHECK_BREAKPOINT
+	bool "Breakpoint on stack overflow"
+	default n
+	depends on ARMV8M_STACKCHECK
+	---help---
+		If enabled, a hard-coded breakpoint will be inserted to the stack
+		overflow trap. This is useful to stop the execution of the program
+		and diagnose the issue before the hardfault handler is called (and
+		context information is lost).
+
 config ARMV8M_ITMSYSLOG
 	bool "ITM SYSLOG support"
 	default n

arch/arm/src/armv8-m/arm_stackcheck.c

@@ -69,6 +69,14 @@ void __stack_overflow_trap(void)
 
   uint32_t regval;
 
+#ifdef CONFIG_ARMV8M_STACKCHECK_BREAKPOINT
+  regval = getreg32(NVIC_DHCSR);
+  if (regval & NVIC_DHCSR_C_DEBUGEN)
+    {
+      __asm("bkpt 1");
+    }
+#endif
+
   /* force hard fault */
 
   regval  = getreg32(NVIC_INTCTRL);