improved runtime error handling

firmware/application/debug.cpp

@@ -29,13 +29,14 @@
 #include "ui_painter.hpp"
 #include "portapack.hpp"
 #include "ui_font_fixed_8x16.hpp"
+#include "string_format.hpp"
 
 void runtime_error(LED);
 std::string number_to_hex_string(uint32_t);
 void draw_line(int32_t, const char *, regarm_t);
 static bool error_shown = false;
 
-extern void draw_guru_meditation_header(uint8_t source, const char *hint) {
+void draw_guru_meditation_header(uint8_t source, const char *hint) {
     ui::Painter painter;
     ui::Style style_default {
         .font = ui::font::fixed_8x16,
@@ -81,7 +82,7 @@ void draw_guru_meditation(uint8_t source, const char *hint) {
     	runtime_error(hackrf::one::led_tx);
 }
 
-void draw_guru_meditation(uint8_t source, const char *hint, struct extctx *ctxp) {
+void draw_guru_meditation(uint8_t source, const char *hint, struct extctx *ctxp, uint32_t cfsr = 0) {
     if(error_shown == false)
     {
         error_shown = true;
@@ -102,6 +103,10 @@ void draw_guru_meditation(uint8_t source, const char *hint, struct extctx *ctxp)
             // to see whats causing the fault.
             draw_line(80 + i++ * 20, "lr:", ctxp->lr_thd);
             draw_line(80 + i++ * 20, "pc:", ctxp->pc);
+
+            // see SCB_CFSR_* in libopencm3/cm3/scb.h for details
+            if (cfsr != 0)
+                draw_line(80 + i++ * 20, "cfsr:", (void *)cfsr);
         }
     }
     
@@ -121,23 +126,7 @@ void draw_line(int32_t y_offset, const char *label, regarm_t value){
     };
 
     painter.draw_string({ 15, y_offset }, style_default, label);
-    painter.draw_string({ 15 + 8*8, y_offset }, style_default, number_to_hex_string((uint32_t)value));
+    painter.draw_string({ 15 + 8*8, y_offset }, style_default, to_string_hex((uint32_t)value, 8));
-}
-
-std::string number_to_hex_string(uint32_t number){
-    char str[16];
-    char* p = &str[16];
-    do {
-        p--;
-        uint32_t digit = number % 16; 
-        number /= 16;
-        *p = digit>=10 ? 'A' + (digit-10) : '0' + digit;
-    } while ( number > 0 );
-    p--;
-    *p = 'x';
-    p--;
-    *p = '0';
-    return std::string(p, &str[16]-p);
 }
 
 void runtime_error(LED led) {
@@ -198,6 +187,11 @@ CH_IRQ_HANDLER(HardFaultVector) {
         ctxp = (struct extctx *)__get_MSP();
 
     port_disable();
+
+    auto stack_space_left = get_free_stack_space();
+    if (stack_space_left < 16)
+        draw_guru_meditation(CORTEX_M0, "Stack Overflow", ctxp);
+
     draw_guru_meditation(CORTEX_M0, "Hard Fault", ctxp);
 
     CH_IRQ_EPILOGUE();

firmware/application/debug.hpp

@@ -26,6 +26,18 @@
 #include "hackrf_gpio.hpp"
 
 extern void draw_guru_meditation(uint8_t, const char *);
-extern void draw_guru_meditation(uint8_t, const char *, struct extctx *);
+extern void draw_guru_meditation(uint8_t, const char *, struct extctx *, uint32_t);
+
+extern uint32_t __process_stack_base__;
+extern uint32_t __process_stack_end__;
+#define CRT0_STACKS_FILL_PATTERN    0x55555555
+
+inline uint32_t get_free_stack_space(){
+    uint32_t *p;
+    for (p = &__process_stack_base__; *p == CRT0_STACKS_FILL_PATTERN && p < &__process_stack_end__; p++);
+    auto stack_space_left = p - &__process_stack_base__;
+
+    return stack_space_left;
+}
 
 #endif/*__DEBUG_H__*/

firmware/application/event_m0.cpp

@@ -145,7 +145,11 @@ void EventDispatcher::dispatch(const eventmask_t events) {
 		if (shared_memory.bb_data.data[0] == 0)
 			draw_guru_meditation(CORTEX_M4, shared_memory.m4_panic_msg);
 		else
-			draw_guru_meditation(CORTEX_M4, shared_memory.m4_panic_msg, (struct extctx *)&shared_memory.bb_data.data[4]);
+			draw_guru_meditation(
+				CORTEX_M4,
+				shared_memory.m4_panic_msg,
+				(struct extctx *)&shared_memory.bb_data.data[8],
+				*(uint32_t *)&shared_memory.bb_data.data[4]);
 	}
 
 	if( events & EVT_MASK_APPLICATION ) {

firmware/baseband/debug.cpp

@@ -33,7 +33,8 @@ void write_m4_panic_msg(const char *panic_message, struct extctx *ctxp) {
     }
     else {
         shared_memory.bb_data.data[0] = 1;
-        memcpy(&shared_memory.bb_data.data[4], ctxp, sizeof(struct extctx));
+        *((uint32_t *)&shared_memory.bb_data.data[4]) = SCB->CFSR;
+        memcpy(&shared_memory.bb_data.data[8], ctxp, sizeof(struct extctx));
     }
 
 	for(size_t i=0; i<sizeof(shared_memory.m4_panic_msg); i++) {
@@ -54,6 +55,10 @@ void port_halt(void) {
         dbg_panic_msg = "system halted";
 
     write_m4_panic_msg(dbg_panic_msg, nullptr);
+
+    while (true) {
+        HALT_IF_DEBUGGING();
+    }
 }
 #endif
 
@@ -85,7 +90,6 @@ CH_IRQ_HANDLER(HardFaultVector) {
 #if CH_DBG_ENABLED
     regarm_t _saved_lr;
     asm volatile ("mov     %0, lr" : "=r" (_saved_lr) : : "memory");
-	CH_IRQ_PROLOGUE();
 
     struct extctx *ctxp;
     port_lock_from_isr();
@@ -95,12 +99,18 @@ CH_IRQ_HANDLER(HardFaultVector) {
     else
         ctxp = (struct extctx *)__get_MSP();
 
-    write_m4_panic_msg("Hard Fault", ctxp);
+    volatile uint32_t stack_space_left = get_free_stack_space();
+    if (stack_space_left < 16)
+        write_m4_panic_msg("Stack Overflow", ctxp);
+    
+    else write_m4_panic_msg("Hard Fault", ctxp);
 
 	port_disable();
-    while (true);
 
-    CH_IRQ_EPILOGUE();
+    while (true) {
+        HALT_IF_DEBUGGING();
+    }
+
 #else
 	chSysHalt();
 #endif

firmware/baseband/debug.hpp

@@ -22,4 +22,25 @@
 #ifndef __DEBUG_H__
 #define __DEBUG_H__
 
+#include <ch.h>
+
+extern uint32_t __process_stack_base__;
+extern uint32_t __process_stack_end__;
+#define CRT0_STACKS_FILL_PATTERN    0x55555555
+
+inline uint32_t get_free_stack_space(){
+    uint32_t *p;
+    for (p = &__process_stack_base__; *p == CRT0_STACKS_FILL_PATTERN && p < &__process_stack_end__; p++);
+    auto stack_space_left = p - &__process_stack_base__;
+
+    return stack_space_left;
+}
+
+#define HALT_IF_DEBUGGING()                              \
+  do {                                                   \
+    if ((*(volatile uint32_t *)0xE000EDF0) & (1 << 0)) { \
+      __asm__ __volatile__("bkpt 1");                    \
+    }                                                    \
+} while (0)
+
 #endif/*__DEBUG_H__*/

firmware/common/chibios_cpp.cpp

@@ -26,11 +26,17 @@
 #include <ch.h>
 
 void* operator new(size_t size) {
-	return chHeapAlloc(0x0, size);
+	void *p = chHeapAlloc(0x0, size);
+	if (p == nullptr)
+		chDbgPanic("Out of Memory");
+	return p;
 }
 
 void* operator new[](size_t size) {
-	return chHeapAlloc(0x0, size);
+	void *p = chHeapAlloc(0x0, size);
+	if (p == nullptr)
+		chDbgPanic("Out of Memory");
+	return p;
 }
 
 void operator delete(void* p) noexcept {