core: cpu: provide function to acquire ISR stack usage

core/include/arch/thread_arch.h

@@ -58,6 +58,11 @@ typedef void *(*thread_task_func_t)(void *arg);
  */
 char *thread_arch_stack_init(thread_task_func_t task_func, void *arg, void *stack_start, int stack_size);
 
+/**
+ * @brief   Get the number of bytes used on the ISR stack
+ */
+int thread_arch_isr_stack_usage(void);
+
 /**
  * @brief Print the current stack to stdout
  */

cpu/arm7_common/arm_cpu.c

@@ -28,6 +28,13 @@ void thread_yield_higher(void)
     __asm__("svc 0\n");
 }
 
+/* This function calculates the ISR_usage */
+int thread_arch_isr_stack_usage(void)
+{
+    /* TODO */
+    return -1;
+}
+
 /*----------------------------------------------------------------------------
  * Processor specific routine - here for ARM7
  * sizeof(void*) = sizeof(int)

cpu/atmega_common/thread_arch.c

@@ -198,6 +198,13 @@ void thread_arch_stack_print(void)
     printf("stack size: %u bytes\n", size);
 }
 
+/* This function calculates the ISR_usage */
+int thread_arch_isr_stack_usage(void)
+{
+    /* TODO */
+    return -1;
+}
+
 void thread_arch_start_threading(void) __attribute__((naked));
 void thread_arch_start_threading(void)
 {

cpu/cortexm_common/include/cpu.h

@@ -48,6 +48,15 @@ extern "C" {
 #define ARCH_HAS_ATOMIC_COMPARE_AND_SWAP 1
 #endif
 
+/**
+ * @brief Interrupt stack canary value
+ *
+ * @note 0xe7fe is the ARM Thumb machine code equivalent of asm("bl #-2\n") or
+ * 'while (1);', i.e. an infinite loop.
+ * @internal
+ */
+#define STACK_CANARY_WORD   (0xE7FEE7FEu)
+
 /**
  * @brief   Initialization of the CPU
  */

cpu/cortexm_common/thread_arch.c

@@ -100,6 +100,9 @@
 #include "irq.h"
 #include "cpu.h"
 
+extern uint32_t _estack;
+extern uint32_t _sstack;
+
 /**
  * @brief   Noticeable marker marking the beginning of a stack segment
  *
@@ -251,6 +254,15 @@ void thread_arch_stack_print(void)
     printf("current stack size: %i byte\n", count);
 }
 
+/* This function returns the number of bytes used on the ISR stack */
+int thread_arch_isr_stack_usage(void)
+{
+    uint32_t  *ptr = &_sstack;
+
+    while (*(ptr++) == STACK_CANARY_WORD) {}
+    return (ISR_STACKSIZE - (ptr - &_sstack));
+}
+
 __attribute__((naked)) void NORETURN thread_arch_start_threading(void)
 {
     __asm__ volatile (

cpu/cortexm_common/vectors_cortexm.c

@@ -31,14 +31,6 @@
 #include "panic.h"
 #include "vectors_cortexm.h"
 
-/**
- * @brief Interrupt stack canary value
- *
- * @note 0xe7fe is the ARM Thumb machine code equivalent of __asm__("bl #-2\n") or
- * 'while (1);', i.e. an infinite loop.
- */
-#define STACK_CANARY_WORD 0xE7FEE7FEu
-
 /**
  * @brief   Memory markers, defined in the linker script
  * @{

cpu/msp430-common/cpu.c

@@ -33,6 +33,13 @@ __attribute__((naked)) void thread_yield_higher(void)
     UNREACHABLE();
 }
 
+/* This function calculates the ISR_usage */
+int thread_arch_isr_stack_usage(void)
+{
+    /* TODO */
+    return -1;
+}
+
 NORETURN void cpu_switch_context_exit(void)
 {
     sched_active_thread = sched_threads[0];

cpu/native/native_cpu.c

@@ -74,6 +74,13 @@ void thread_print_stack(void)
     return;
 }
 
+/* This function calculates the ISR_usage */
+int thread_arch_isr_stack_usage(void)
+{
+    /* TODO */
+    return -1;
+}
+
 char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_start, int stacksize)
 {
     char *stk;

cpu/x86/x86_thread_arch.c

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2016 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @author  Martine Lenders <mlenders@inf.fu-berlin.de>
+ */
+
+#include "thread_arch.h"
+
+/* This function calculates the ISR_usage */
+int thread_arch_isr_stack_usage(void)
+{
+    /* TODO */
+    return -1;
+}
+
+/** @} */