core: save the stack_start in the thread context for mpu_stack_guard

core/include/thread.h

@@ -189,7 +189,7 @@ struct _thread {
     msg_t *msg_array;               /**< memory holding messages        */
 #endif
 
-#if defined DEVELHELP || defined(SCHED_TEST_STACK)
+#if defined(DEVELHELP) || defined(SCHED_TEST_STACK) || defined(MODULE_MPU_STACK_GUARD)
     char *stack_start;              /**< thread's stack start address   */
 #endif
 #ifdef DEVELHELP

core/sched.c

@@ -29,6 +29,10 @@
 #include "irq.h"
 #include "log.h"
 
+#ifdef MODULE_MPU_STACK_GUARD
+#include "mpu.h"
+#endif
+
 #ifdef MODULE_SCHEDSTATISTICS
 #include "xtimer.h"
 #endif
@@ -115,6 +119,16 @@ int __attribute__((used)) sched_run(void)
     sched_active_pid = next_thread->pid;
     sched_active_thread = (volatile thread_t *) next_thread;
 
+#ifdef MODULE_MPU_STACK_GUARD
+    mpu_configure(
+        1,                                                /* MPU region 1 */
+        (uintptr_t)sched_active_thread->stack_start + 31, /* Base Address (rounded up) */
+        MPU_ATTR(1, AP_RO_RO, 0, 1, 0, 1, MPU_SIZE_32B)   /* Attributes and Size */
+    );
+
+    mpu_enable();
+#endif
+
     DEBUG("sched_run: done, changed sched_active_thread.\n");
 
     return 1;

core/thread.c

@@ -211,7 +211,7 @@ kernel_pid_t thread_create(char *stack, int stacksize, char priority, int flags,
     cb->pid = pid;
     cb->sp = thread_stack_init(function, arg, stack, stacksize);
 
-#if defined(DEVELHELP) || defined(SCHED_TEST_STACK)
+#if defined(DEVELHELP) || defined(SCHED_TEST_STACK) || defined(MODULE_MPU_STACK_GUARD)
     cb->stack_start = stack;
 #endif
 

tests/sizeof_tcb/main.c

@@ -48,7 +48,7 @@ int main(void)
 #ifdef DEVELHELP
     P(name);
 #endif
-#if defined(DEVELHELP) || defined(SCHED_TEST_STACK)
+#if defined(DEVELHELP) || defined(SCHED_TEST_STACK) || defined(MODULE_MPU_STACK_GUARD)
     P(stack_start);
 #endif