[rtems commit] libtests/ofw01: Fix wrapped in bsp_fdt_get()

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    963a26c34b89d1d2d2ea6ffde251b771b68ac5ef
Changeset: http://git.rtems.org/rtems/commit/?id=963a26c34b89d1d2d2ea6ffde251b771b68ac5ef

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Tue Jan 11 11:45:47 2022 +0100

libtests/ofw01: Fix wrapped in bsp_fdt_get()

Use the stack pointer to check if we have to return the real device tree
since bsp_fdt_get() may get called before the BSS is cleared to zero.

---

 testsuites/libtests/ofw01/init.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/testsuites/libtests/ofw01/init.c b/testsuites/libtests/ofw01/init.c
index 6006121..6afed33 100644
--- a/testsuites/libtests/ofw01/init.c
+++ b/testsuites/libtests/ofw01/init.c
@@ -37,6 +37,7 @@
 #include <bsp/fdt.h>
 #include <ofw/ofw.h>
 #include <ofw/ofw_test.h>
+#include <rtems/score/isr.h>
 
 #include "some.h"
 
@@ -50,7 +51,20 @@ const void *__real_bsp_fdt_get(void);
 
 const void *__wrap_bsp_fdt_get(void)
 {
-  if (test_bin != NULL) {
+  uintptr_t sp;
+
+  sp = (uintptr_t) __builtin_frame_address(0);
+  RTEMS_OBFUSCATE_VARIABLE(sp);
+
+  /*
+   * Use the stack pointer to check if we have to return the real device tree
+   * since bsp_fdt_get() may get called before the BSS is cleared to zero.
+   */
+  if (
+    (sp < (uintptr_t) _ISR_Stack_area_begin ||
+    sp >= (uintptr_t) _ISR_Stack_area_end) &&
+    test_bin != NULL
+  ) {
     return test_bin;
   }