tests/cpu: add basic test for cortexm_stack_limit module

Signed-off-by: Dylan Laduranty <dylan.laduranty@mesotic.com>

tests/cpu/cortexm_stack_limit/Makefile

@@ -0,0 +1,11 @@
+BOARD ?= nrf5340dk-app
+
+include ../Makefile.cpu_common
+
+FEATURES_REQUIRED += cortexm_stack_limit
+
+include $(RIOTBASE)/Makefile.include
+
+ifeq (llvm,$(TOOLCHAIN))
+  CFLAGS += -Wno-infinite-recursion
+endif

tests/cpu/cortexm_stack_limit/main.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2024 Mesotic SAS
+ *
+ * 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.
+ */
+
+/**
+ * @ingroup tests
+ * @{
+ *
+ * @file
+ * @brief Test application for the cortexm_stack_limit pseudo-module
+ *
+ * @author Dylan Laduranty <dylan.laduranty@mesotic.com>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+
+#include "cpu.h"
+#include "thread.h"
+#include "board.h"
+
+#define CANARY_VALUE 0xdeadbeef
+
+static struct {
+    unsigned int canary;
+    char stack[THREAD_STACKSIZE_MAIN];
+} buf;
+
+/* Tell modern GCC (12.x) to not complain that this infinite recursion is
+ * bound to overflow the stack - this is exactly what this test wants to do :)
+ *
+ * Also, tell older versions of GCC that do not know about -Winfinit-recursion
+ * that it is safe to ignore `GCC diagnostics ignored "-Winfinit-recursion"`.
+ * They behave as intended in this case :)
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpragmas"
+#pragma GCC diagnostic ignored "-Winfinite-recursion"
+static int recurse(int counter)
+{
+    if (buf.canary != CANARY_VALUE) {
+#ifdef LED0_ON
+        LED0_ON;
+#endif
+#ifdef LED1_ON
+        LED1_ON;
+#endif
+#ifdef LED2_ON
+        LED2_ON;
+#endif
+#ifdef LED3_ON
+        LED3_ON;
+#endif
+
+        for (;;) {
+            thread_sleep();
+        }
+    }
+
+    counter++;
+    /* Recursing twice here prevents the compiler from optimizing-out the recursion. */
+    return recurse(counter) + recurse(counter);
+}
+#pragma GCC diagnostic pop
+
+static void *thread(void *arg)
+{
+    (void) arg;
+
+    recurse(0);
+
+    return NULL;
+}
+
+int main(void)
+{
+    puts("\nCortex-M Stack limit test\n");
+
+    puts("If the test fails, all onboard LEDs will be on");
+
+#ifdef MODULE_CORTEXM_STACK_LIMIT
+    puts("The cortexm_stack_limit module is present. Expect the board to crash"\
+         " without onboard LEDs on.\n");
+#else
+    puts("The cortexm_stack_limit module is missing! Expect the test to crash"\
+         " with all onboard LEDs on\n");
+#endif
+
+    buf.canary = CANARY_VALUE;
+    thread_create(buf.stack, sizeof(buf.stack), THREAD_PRIORITY_MAIN + 1,
+                  0, thread, NULL, "thread");
+
+    return 0;
+}