config: Add CONFIGURE_IDLE_TASK_STORAGE_SIZE

By default, allocate the IDLE task storage areas from the RTEMS Workspace.
This avoids having to estimate the thread-local storage size in the default
configuration.

Add the application configuration option CONFIGURE_IDLE_TASK_STORAGE_SIZE to
request a static allocation of the task storage area for IDLE tasks.

Update #3835.
Update #4524.

6 files changed, 104 insertions, 32 deletions

diff --git a/cpukit/include/rtems/confdefs/percpu.h b/cpukit/include/rtems/confdefs/percpu.h
index b91590bfd9..a6b35e0eaf 100644
--- a/cpukit/include/rtems/confdefs/percpu.h
+++ b/cpukit/include/rtems/confdefs/percpu.h
@@ -136,20 +136,6 @@ RTEMS_DEFINE_GLOBAL_SYMBOL(
 
 const size_t _Thread_Idle_stack_size = CONFIGURE_IDLE_TASK_STACK_SIZE;
 
-/*
- * If the user provides a custom idle stack allocator, then we do not need
- * memory reserved for the stacks but the symbol is still referenced in
- * threadcreateidle.c. The code path just never uses it. Make it minimal
- * size to proceed.
- */
-#ifndef CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE
-  char _Thread_Idle_stacks[
-    _CONFIGURE_MAXIMUM_PROCESSORS
-      * ( CONFIGURE_IDLE_TASK_STACK_SIZE + CPU_IDLE_TASK_IS_FP * CONTEXT_FP_SIZE )
-  ] RTEMS_ALIGNED( CPU_INTERRUPT_STACK_ALIGNMENT )
-  RTEMS_SECTION( ".rtemsstack.idle" );
-#endif
-
 #if defined(CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION) && \
   !defined(CONFIGURE_IDLE_TASK_BODY)
   #error "If you define CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION, then you must define CONFIGURE_IDLE_TASK_BODY as well"
diff --git a/cpukit/include/rtems/confdefs/threads.h b/cpukit/include/rtems/confdefs/threads.h
index 4040bcb50a..5ccfffaf6e 100644
--- a/cpukit/include/rtems/confdefs/threads.h
+++ b/cpukit/include/rtems/confdefs/threads.h
@@ -235,6 +235,10 @@ const size_t _Thread_Control_add_on_count =
 #endif
 
 const size_t _Thread_Initial_thread_count =
+#if !defined(CONFIGURE_IDLE_TASK_STORAGE_SIZE) && \
+  !defined(CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE)
+  _CONFIGURE_MAXIMUM_PROCESSORS +
+#endif
   rtems_resource_maximum_per_allocation( _CONFIGURE_TASKS ) +
   rtems_resource_maximum_per_allocation( CONFIGURE_MAXIMUM_POSIX_THREADS );
 
diff --git a/cpukit/include/rtems/confdefs/wkspace.h b/cpukit/include/rtems/confdefs/wkspace.h
index 82de8633bf..da766fd8af 100644
--- a/cpukit/include/rtems/confdefs/wkspace.h
+++ b/cpukit/include/rtems/confdefs/wkspace.h
@@ -47,6 +47,7 @@
 #include <rtems/confdefs/inittask.h>
 #include <rtems/confdefs/initthread.h>
 #include <rtems/confdefs/objectsposix.h>
+#include <rtems/confdefs/percpu.h>
 #include <rtems/confdefs/threads.h>
 #include <rtems/confdefs/wkspacesupport.h>
 #include <rtems/score/coremsg.h>
@@ -111,8 +112,18 @@
     + 1024 * CONFIGURE_MEMORY_OVERHEAD \
     + _CONFIGURE_HEAP_HANDLER_OVERHEAD )
 
+#if defined(CONFIGURE_IDLE_TASK_STORAGE_SIZE) || \
+  defined(CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE)
+  #define _CONFIGURE_IDLE_TASK_STACKS 0
+#else
+  #define _CONFIGURE_IDLE_TASK_STACKS \
+    ( _CONFIGURE_MAXIMUM_PROCESSORS * \
+      _Configure_From_stackspace( CONFIGURE_IDLE_TASK_STACK_SIZE ) )
+#endif
+
 #define _CONFIGURE_STACK_SPACE_SIZE \
   ( _CONFIGURE_INIT_TASK_STACK_EXTRA \
+    + _CONFIGURE_IDLE_TASK_STACKS \
     + _CONFIGURE_POSIX_INIT_THREAD_STACK_EXTRA \
     + _CONFIGURE_LIBBLOCK_TASKS_STACK_EXTRA \
     + CONFIGURE_EXTRA_TASK_STACKS \
@@ -212,15 +223,40 @@ const uintptr_t _Stack_Space_size = _CONFIGURE_STACK_SPACE_SIZE;
   #error "CONFIGURE_TASK_STACK_ALLOCATOR and CONFIGURE_TASK_STACK_DEALLOCATOR must be both defined or both undefined"
 #endif
 
-/*
- * Custom IDLE thread stacks allocator. If this is provided, it is assumed
- * that the allocator is providing its own memory for these stacks.
- */
-#ifdef CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE
-  const Stack_Allocator_allocate_for_idle _Stack_Allocator_allocate_for_idle =
-    CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE;
+#ifdef CONFIGURE_IDLE_TASK_STORAGE_SIZE
+  #ifdef CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE
+    #error "CONFIGURE_IDLE_TASK_STORAGE_SIZE and CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE are mutually exclusive"
+  #endif
+
+  #define _CONFIGURE_IDLE_TASK_STORAGE_SIZE \
+    RTEMS_ALIGN_UP( \
+      RTEMS_TASK_STORAGE_SIZE( \
+        CONFIGURE_IDLE_TASK_STORAGE_SIZE, \
+        RTEMS_DEFAULT_ATTRIBUTES \
+      ), \
+      CPU_INTERRUPT_STACK_ALIGNMENT \
+    )
+
+  const size_t _Stack_Allocator_allocate_for_idle_storage_size =
+    _CONFIGURE_IDLE_TASK_STORAGE_SIZE;
+
+  char _Stack_Allocator_allocate_for_idle_storage_areas[
+    _CONFIGURE_MAXIMUM_PROCESSORS * _CONFIGURE_IDLE_TASK_STORAGE_SIZE
+  ] RTEMS_ALIGNED( CPU_INTERRUPT_STACK_ALIGNMENT )
+  RTEMS_SECTION( ".rtemsstack.idle" );
+
+  #define CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE \
+    _Stack_Allocator_allocate_for_idle_static
 #endif
 
+#ifndef CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE
+  #define CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE \
+    _Stack_Allocator_allocate_for_idle_workspace
+#endif
+
+const Stack_Allocator_allocate_for_idle _Stack_Allocator_allocate_for_idle =
+  CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE;
+
 #ifdef CONFIGURE_DIRTY_MEMORY
   RTEMS_SYSINIT_ITEM(
     _Memory_Dirty_free_areas,
diff --git a/cpukit/include/rtems/score/interr.h b/cpukit/include/rtems/score/interr.h
index d0ecf0f5c8..f21e8d58a1 100644
--- a/cpukit/include/rtems/score/interr.h
+++ b/cpukit/include/rtems/score/interr.h
@@ -229,7 +229,8 @@ typedef enum {
   INTERNAL_ERROR_NO_MEMORY_FOR_PER_CPU_DATA = 40,
   INTERNAL_ERROR_TOO_LARGE_TLS_SIZE = 41,
   INTERNAL_ERROR_RTEMS_INIT_TASK_CONSTRUCT_FAILED = 42,
-  INTERNAL_ERROR_IDLE_THREAD_CREATE_FAILED = 43
+  INTERNAL_ERROR_IDLE_THREAD_CREATE_FAILED = 43,
+  INTERNAL_ERROR_NO_MEMORY_FOR_IDLE_TASK_STORAGE = 44
 } Internal_errors_Core_list;
 
 typedef CPU_Uint32ptr Internal_errors_t;
diff --git a/cpukit/include/rtems/score/stack.h b/cpukit/include/rtems/score/stack.h
index 7577ca0474..9326480373 100644
--- a/cpukit/include/rtems/score/stack.h
+++ b/cpukit/include/rtems/score/stack.h
@@ -11,8 +11,8 @@
  */
 
 /*
- *  COPYRIGHT (c) 1989-2006.
- *  On-Line Applications Research Corporation (OAR).
+ * Copyright (C) 2022 embedded brains GmbH
+ * Copyright (C) 1989, 2021 On-Line Applications Research Corporation (OAR)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -172,7 +172,57 @@ extern const Stack_Allocator_free _Stack_Allocator_free;
  */
 void _Stack_Allocator_do_initialize( void );
 
-/** @} */
+/**
+ * @brief Allocates the IDLE thread storage area from the workspace.
+ *
+ * If the thread storage area cannot be allocated, then the
+ * ::INTERNAL_ERROR_NO_MEMORY_FOR_IDLE_TASK_STACK fatal error will occur.
+ *
+ * @param unused is an unused parameter.
+ *
+ * @param stack_size[in] is pointer to a size_t object.  On function entry, the
+ *   object contains the size of the task storage area to allocate in bytes.
+ *
+ * @return Returns a pointer to the begin of the allocated task storage area.
+ */
+void *_Stack_Allocator_allocate_for_idle_workspace(
+  uint32_t  unused,
+  size_t   *storage_size
+);
+
+/**
+ * @brief The size in bytes of the idle thread storage area used by
+ *   _Stack_Allocator_allocate_for_idle_static().
+ *
+ * Application provided via <rtems/confdefs.h>.
+ */
+extern const size_t _Stack_Allocator_allocate_for_idle_storage_size;
+
+/**
+ * @brief The thread storage areas used by
+ *   _Stack_Allocator_allocate_for_idle_static().
+ *
+ * Application provided via <rtems/confdefs.h>.
+ */
+extern char _Stack_Allocator_allocate_for_idle_storage_areas[];
+
+/**
+ * @brief Allocates the IDLE thread storage from the memory statically
+ *   allocated by <rtems/confdefs.h>.
+ *
+ * @param cpu_index is the index of the CPU for the IDLE thread using this stack.
+ *
+ * @param stack_size[out] is pointer to a size_t object.  On function return, the
+ *   object value is set to the value of
+ *   ::_Stack_Allocator_allocate_for_idle_storage_size.
+ *
+ * @return Returns a pointer to the begin of the allocated task storage area.
+ */
+void *_Stack_Allocator_allocate_for_idle_static(
+  uint32_t  cpu_index,
+  size_t   *storage_size
+);
+
 /**
  * @brief The stack allocator allocate stack for idle thread handler.
  *
@@ -181,6 +231,8 @@ void _Stack_Allocator_do_initialize( void );
 extern const Stack_Allocator_allocate_for_idle
   _Stack_Allocator_allocate_for_idle;
 
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/cpukit/include/rtems/score/thread.h b/cpukit/include/rtems/score/thread.h
index f82d4b954c..2b4d6823f0 100644
--- a/cpukit/include/rtems/score/thread.h
+++ b/cpukit/include/rtems/score/thread.h
@@ -1186,13 +1186,6 @@ Thread_Information name##_Information = { \
   } \
 }
 
-/**
- * @brief The idle thread stacks.
- *
- * Provided by the application via <rtems/confdefs.h>.
- */
-extern char _Thread_Idle_stacks[];
-
 #if defined(RTEMS_MULTIPROCESSING)
 /**
  * @brief The configured thread control block.