sysinit: Add RTEMS_SYSINIT_ZERO_MEMORY

Use a dedicate system initialization step to zero the memory used for
the workspace and C program heap.

This avoids dead code in case CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY is
not configured.

4 files changed, 27 insertions, 15 deletions

diff --git a/cpukit/include/rtems/confdefs.h b/cpukit/include/rtems/confdefs.h
index 7d0d3fbeab..982e3ddb56 100644
--- a/cpukit/include/rtems/confdefs.h
+++ b/cpukit/include/rtems/confdefs.h
@@ -2778,11 +2778,6 @@ struct _reent *__getreent(void)
     CONFIGURE_TASK_STACK_ALLOCATOR_INIT,      /* stack allocator init */
     CONFIGURE_TASK_STACK_ALLOCATOR,           /* stack allocator */
     CONFIGURE_TASK_STACK_DEALLOCATOR,         /* stack deallocator */
-    #ifdef CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY /* true to clear memory */
-      true,
-    #else
-      false,
-    #endif
     #ifdef CONFIGURE_UNIFIED_WORK_AREAS       /* true for unified work areas */
       true,
     #else
@@ -2807,6 +2802,16 @@ struct _reent *__getreent(void)
     #endif
   };
 
+  #ifdef CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY
+    const bool _Memory_Zero_before_use = true;
+
+    RTEMS_SYSINIT_ITEM(
+      _Memory_Zero_free_areas,
+      RTEMS_SYSINIT_ZERO_MEMORY,
+      RTEMS_SYSINIT_ORDER_MIDDLE
+    );
+  #endif
+
   #if CONFIGURE_RECORD_PER_PROCESSOR_ITEMS > 0
     #if (CONFIGURE_RECORD_PER_PROCESSOR_ITEMS & (CONFIGURE_RECORD_PER_PROCESSOR_ITEMS - 1)) != 0
       #error "CONFIGURE_RECORD_PER_PROCESSOR_ITEMS must be a power of two"
diff --git a/cpukit/include/rtems/config.h b/cpukit/include/rtems/config.h
index 15e944dd2f..fac5c6e009 100644
--- a/cpukit/include/rtems/config.h
+++ b/cpukit/include/rtems/config.h
@@ -29,6 +29,7 @@
 
 #include <rtems/score/object.h>
 #include <rtems/score/isr.h>
+#include <rtems/score/memory.h>
 #include <rtems/score/userextdata.h>
 #include <rtems/score/watchdogticks.h>
 #include <rtems/rtems/config.h>
@@ -148,14 +149,6 @@ typedef struct {
    */
   rtems_stack_free_hook          stack_free_hook;
 
-  /** 
-   * If this element is TRUE, then RTEMS will zero the Executive Workspace.
-   * When this element is FALSE, it is assumed that the BSP or invoking
-   * environment has ensured that memory was cleared before RTEMS was
-   * invoked.
-   */
-  bool                           do_zero_of_workspace;
-
   /**
    * @brief Specifies if a unified work area is used or not.
    *
@@ -241,7 +234,7 @@ uint32_t rtems_configuration_get_maximum_extensions( void );
   * RTEMS is responsible for zeroing the Executive Workspace.
   */
 #define rtems_configuration_get_do_zero_of_workspace() \
-   (Configuration.do_zero_of_workspace)
+  _Memory_Zero_before_use
 
 #define rtems_configuration_get_number_of_initial_extensions() \
   ((uint32_t) _User_extensions_Initial_count)
diff --git a/cpukit/include/rtems/score/memory.h b/cpukit/include/rtems/score/memory.h
index f26c7f4031..ffc4897ed5 100644
--- a/cpukit/include/rtems/score/memory.h
+++ b/cpukit/include/rtems/score/memory.h
@@ -331,6 +331,19 @@ void *_Memory_Allocate(
  */
 void _Memory_Fill( const Memory_Information *information, int c );
 
+/**
+ * @brief Indicates if the memory is zeroed during system initialization.
+ *
+ * This value is provided via <rtems/confdefs.h> in case
+ * CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY is defined.
+ */
+extern const bool _Memory_Zero_before_use;
+
+/**
+ * @brief Zeros all free memory areas of the system.
+ */
+void _Memory_Zero_free_areas( void );
+
 /** @} */
 
 #ifdef __cplusplus
diff --git a/cpukit/include/rtems/sysinit.h b/cpukit/include/rtems/sysinit.h
index 58f35542b7..d181c42780 100644
--- a/cpukit/include/rtems/sysinit.h
+++ b/cpukit/include/rtems/sysinit.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2018 embedded brains GmbH.  All rights reserved.
+ * Copyright (c) 2015, 2020 embedded brains GmbH.  All rights reserved.
  *
  *  embedded brains GmbH
  *  Dornierstr. 4
@@ -30,6 +30,7 @@ extern "C" {
 #define RTEMS_SYSINIT_BSP_EARLY                  000140
 #define RTEMS_SYSINIT_MEMORY                     000180
 #define RTEMS_SYSINIT_DIRTY_MEMORY               0001c0
+#define RTEMS_SYSINIT_ZERO_MEMORY                0001e0
 #define RTEMS_SYSINIT_ISR_STACK                  000200
 #define RTEMS_SYSINIT_PER_CPU_DATA               000220
 #define RTEMS_SYSINIT_SBRK                       000240