Rework initialization and interrupt stack support

Statically initialize the interrupt stack area
(_Configuration_Interrupt_stack_area_begin,
_Configuration_Interrupt_stack_area_end, and
_Configuration_Interrupt_stack_size) via <rtems/confdefs.h>.  Place the
interrupt stack area in a special section ".rtemsstack.interrupt".  Let
BSPs define the optimal placement of this section in their linker
command files (e.g. in a fast on-chip memory).

This change makes makes the CPU_HAS_SOFTWARE_INTERRUPT_STACK and
CPU_HAS_HARDWARE_INTERRUPT_STACK CPU port defines superfluous, since the
low level initialization code has all information available via global
symbols.

This change makes the CPU_ALLOCATE_INTERRUPT_STACK CPU port define
superfluous, since the interrupt stacks are allocated by confdefs.h for
all architectures.  There is no need for BSP-specific linker command
file magic (except the section placement), see previous ARM linker
command file as a bad example.

Remove _CPU_Install_interrupt_stack().  Initialize the hardware
interrupt stack in _CPU_Initialize() if necessary (e.g.
m68k_install_interrupt_stack()).

The optional _CPU_Interrupt_stack_setup() is still useful to customize
the registration of the interrupt stack area in the per-CPU information.

The initialization stack can reuse the interrupt stack, since

  * interrupts are disabled during the sequential system initialization,
    and

  * the boot_card() function does not return.

This stack resuse saves memory.

Changes per architecture:

arm:

  * Mostly replace the linker symbol based configuration of stacks with
    the standard <rtems/confdefs.h> configuration via
    CONFIGURE_INTERRUPT_STACK_SIZE.  The size of the FIQ, ABT and UND
    mode stack is still defined via linker symbols.  These modes are
    rarely used in applications and the default values provided by the
    BSP should be sufficient in most cases.

  * Remove the bsp_processor_count linker symbol hack used for the SMP
    support. This is possible since the interrupt stack area is now
    allocated by the linker and not allocated from the heap.  This makes
    some configure.ac stuff obsolete.  Remove the now superfluous BSP
    variants altcycv_devkit_smp and realview_pbx_a9_qemu_smp.

bfin:

  * Remove unused magic linker command file allocation of initialization
    stack.  Maybe a previous linker command file copy and paste problem?
    In the start.S the initialization stack is set to a hard coded value.

lm32, m32c, mips, nios2, riscv, sh, v850:

  * Remove magic linker command file allocation of initialization stack.
    Reuse interrupt stack for initialization stack.

m68k:

  * Remove magic linker command file allocation of initialization stack.
    Reuse interrupt stack for initialization stack.

powerpc:

  * Remove magic linker command file allocation of initialization stack.
    Reuse interrupt stack for initialization stack.

  * Used dedicated memory region (REGION_RTEMSSTACK) for the interrupt
    stack on BSPs using the shared linkcmds.base (replacement for
    REGION_RWEXTRA).

sparc:

  * Remove the hard coded initialization stack.  Use the interrupt stack
    for the initialization stack on the boot processor.  This saves
    16KiB of RAM.

Update #3459.

3 files changed, 66 insertions, 76 deletions

diff --git a/cpukit/include/rtems/confdefs.h b/cpukit/include/rtems/confdefs.h
index 7f3ffdff0d..e56826af5a 100644
--- a/cpukit/include/rtems/confdefs.h
+++ b/cpukit/include/rtems/confdefs.h
@@ -1182,12 +1182,13 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
   #error "CONFIGURE_IDLE_TASK_STACK_SIZE less than CONFIGURE_MINIMUM_TASK_STACK_SIZE"
 #endif
 
-/**
- * @brief Interrupt stack size configuration.
+/*
+ * Interrupt stack configuration.
  *
  * By default, the interrupt stack will be of minimum size.
  * The BSP or application may override this value.
  */
+
 #ifndef CONFIGURE_INTERRUPT_STACK_SIZE
   #ifdef BSP_INTERRUPT_STACK_SIZE
     #define CONFIGURE_INTERRUPT_STACK_SIZE BSP_INTERRUPT_STACK_SIZE
@@ -1196,18 +1197,23 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
   #endif
 #endif
 
-/**
- * This reserves memory for the interrupt stack if it is to be allocated
- * by RTEMS rather than the BSP.
- *
- * @todo Try to get to the point where all BSPs support allocating the
- *       memory from the Workspace.
- */
-#if (CPU_ALLOCATE_INTERRUPT_STACK == 0)
-  #define _CONFIGURE_INTERRUPT_STACK_MEMORY 0
-#else
-  #define _CONFIGURE_INTERRUPT_STACK_MEMORY \
-     _Configure_From_workspace( CONFIGURE_INTERRUPT_STACK_SIZE )
+#if CONFIGURE_INTERRUPT_STACK_SIZE % CPU_INTERRUPT_STACK_ALIGNMENT != 0
+  #error "CONFIGURE_INTERRUPT_STACK_SIZE fails to meet the CPU port interrupt stack alignment"
+#endif
+
+#ifdef CONFIGURE_INIT
+  RTEMS_DEFINE_GLOBAL_SYMBOL(
+    _Configuration_Interrupt_stack_size,
+    CONFIGURE_INTERRUPT_STACK_SIZE
+  );
+
+  char _Configuration_Interrupt_stack_area_begin[
+    CONFIGURE_MAXIMUM_PROCESSORS * CONFIGURE_INTERRUPT_STACK_SIZE
+  ] RTEMS_ALIGNED( CPU_INTERRUPT_STACK_ALIGNMENT )
+  RTEMS_SECTION( ".rtemsstack.interrupt.begin" );
+
+  const char _Configuration_Interrupt_stack_area_end[ 0 ]
+    RTEMS_SECTION( ".rtemsstack.interrupt.end" ) = { };
 #endif
 
 /**
@@ -2720,9 +2726,7 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
  * This macro accounts for general RTEMS system overhead.
  */
 #define _CONFIGURE_MEMORY_FOR_SYSTEM_OVERHEAD \
-  ( _CONFIGURE_MEMORY_FOR_INTERNAL_TASKS + \
-    _CONFIGURE_INTERRUPT_STACK_MEMORY \
-  )
+  _CONFIGURE_MEMORY_FOR_INTERNAL_TASKS
 
 /**
  * This macro reserves the memory required by the statically configured
@@ -2752,18 +2756,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
    _CONFIGURE_MEMORY_FOR_USER_EXTENSIONS(CONFIGURE_MAXIMUM_USER_EXTENSIONS) \
   )
 
-/*
- * This macro provides a summation of the memory required by SMP as configured.
- */
-#if defined(RTEMS_SMP)
-  #define _CONFIGURE_MEMORY_FOR_SMP \
-     (CONFIGURE_MAXIMUM_PROCESSORS * \
-      _Configure_From_workspace( CONFIGURE_INTERRUPT_STACK_SIZE ) \
-     )
-#else
-  #define _CONFIGURE_MEMORY_FOR_SMP 0
-#endif
-
 /**
  * This calculates the memory required for the executive workspace.
  *
@@ -2783,7 +2775,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
    _CONFIGURE_MEMORY_FOR_POSIX + \
    _CONFIGURE_MEMORY_FOR_STATIC_EXTENSIONS + \
    _CONFIGURE_MEMORY_FOR_MP + \
-   _CONFIGURE_MEMORY_FOR_SMP + \
    CONFIGURE_MESSAGE_BUFFER_MEMORY + \
    (CONFIGURE_MEMORY_OVERHEAD * 1024) + \
    _CONFIGURE_HEAP_HANDLER_OVERHEAD \
@@ -3082,7 +3073,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
     CONFIGURE_TICKS_PER_TIMESLICE,            /* ticks per timeslice quantum */
     CONFIGURE_IDLE_TASK_BODY,                 /* user's IDLE task */
     CONFIGURE_IDLE_TASK_STACK_SIZE,           /* IDLE task stack size */
-    CONFIGURE_INTERRUPT_STACK_SIZE,           /* interrupt stack size */
     CONFIGURE_TASK_STACK_ALLOCATOR_INIT,      /* stack allocator init */
     CONFIGURE_TASK_STACK_ALLOCATOR,           /* stack allocator */
     CONFIGURE_TASK_STACK_DEALLOCATOR,         /* stack deallocator */
@@ -3239,7 +3229,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
     uint32_t POSIX;
 
     /* System overhead pieces */
-    uint32_t INTERRUPT_STACK_MEMORY;
     uint32_t MEMORY_FOR_IDLE_TASK;
 
     /* Classic API Pieces */
@@ -3288,7 +3277,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
     _CONFIGURE_MEMORY_FOR_POSIX,
 
     /* System overhead pieces */
-    _CONFIGURE_INTERRUPT_STACK_MEMORY,
     _CONFIGURE_MEMORY_FOR_INTERNAL_TASKS,
 
     /* Classic API Pieces */
diff --git a/cpukit/include/rtems/config.h b/cpukit/include/rtems/config.h
index 6b97376511..248ace0721 100644
--- a/cpukit/include/rtems/config.h
+++ b/cpukit/include/rtems/config.h
@@ -184,13 +184,6 @@ typedef struct {
    */
   uint32_t                       idle_task_stack_size;
 
-  /** 
-   * This field specifies the size of the interrupt stack.  If less than or
-   * equal to the minimum stack size, then the interrupt stack will be of
-   * minimum stack size.
-   */
-  uint32_t                       interrupt_stack_size;
-
   /**
    * @brief Optional task stack allocator initialization hook.
    */
@@ -313,8 +306,34 @@ extern const rtems_configuration_table Configuration;
 #define rtems_configuration_get_idle_task_stack_size() \
         (Configuration.idle_task_stack_size)
 
+/**
+ * @brief Global symbol with a value equal to the configure interrupt stack size.
+ *
+ * This global symbol is defined by the application configuration option
+ * CONFIGURE_INIT_TASK_STACK_SIZE via <rtems/confdefs.h>.
+ */
+RTEMS_DECLARE_GLOBAL_SYMBOL( _Configuration_Interrupt_stack_size );
+
+/**
+ * @brief The interrupt stack area begin.
+ *
+ * The interrupt stack area is defined by the application configuration via
+ * <rtems/confdefs.h>.  The size of the area depends on
+ * CONFIGURE_INIT_TASK_STACK_SIZE and CONFIGURE_MAXIMUM_PROCESSORS.
+ */
+extern char _Configuration_Interrupt_stack_area_begin[];
+
+/**
+ * @brief The interrupt stack area end.
+ *
+ * The interrupt stack area is defined by the application configuration via
+ * <rtems/confdefs.h>.  The size of the area depends on
+ * CONFIGURE_INIT_TASK_STACK_SIZE and CONFIGURE_MAXIMUM_PROCESSORS.
+ */
+extern const char _Configuration_Interrupt_stack_area_end[];
+
 #define rtems_configuration_get_interrupt_stack_size() \
-        (Configuration.interrupt_stack_size)
+        ((size_t) _Configuration_Interrupt_stack_size)
 
 #define rtems_configuration_get_stack_allocate_init_hook() \
         (Configuration.stack_allocate_init_hook)
diff --git a/cpukit/include/rtems/score/percpu.h b/cpukit/include/rtems/score/percpu.h
index 7d0a6c06bf..4a8353db47 100644
--- a/cpukit/include/rtems/score/percpu.h
+++ b/cpukit/include/rtems/score/percpu.h
@@ -293,20 +293,15 @@ typedef struct Per_CPU_Control {
     CPU_Per_CPU_control cpu_per_cpu;
   #endif
 
-  #if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE) || \
-      (CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE)
-    /**
-     * This contains a pointer to the lower range of the interrupt stack for
-     * this CPU.  This is the address allocated and freed.
-     */
-    void  *interrupt_stack_low;
+  /**
+   * @brief The interrupt stack low address for this processor.
+   */
+  void *interrupt_stack_low;
 
-    /**
-     * This contains a pointer to the interrupt stack pointer for this CPU.
-     * It will be loaded at the beginning on an ISR.
-     */
-    void  *interrupt_stack_high;
-  #endif
+  /**
+   * @brief The interrupt stack high address for this processor.
+   */
+  void *interrupt_stack_high;
 
   /**
    *  This contains the current interrupt nesting level on this
@@ -800,33 +795,21 @@ RTEMS_INLINE_ROUTINE struct _Thread_Control *_Thread_Get_executing( void )
 
 #if defined( ASM ) || defined( _RTEMS_PERCPU_DEFINE_OFFSETS )
 
-#if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE) || \
-    (CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE)
-  /*
-   *  If this CPU target lets RTEMS allocates the interrupt stack, then
-   *  we need to have places in the per CPU table to hold them.
-   */
-  #define PER_CPU_INTERRUPT_STACK_LOW \
-    CPU_PER_CPU_CONTROL_SIZE
-  #define PER_CPU_INTERRUPT_STACK_HIGH \
-    PER_CPU_INTERRUPT_STACK_LOW + CPU_SIZEOF_POINTER
-  #define PER_CPU_END_STACK             \
-    PER_CPU_INTERRUPT_STACK_HIGH + CPU_SIZEOF_POINTER
-
-  #define INTERRUPT_STACK_LOW \
-    (SYM(_Per_CPU_Information) + PER_CPU_INTERRUPT_STACK_LOW)
-  #define INTERRUPT_STACK_HIGH \
-    (SYM(_Per_CPU_Information) + PER_CPU_INTERRUPT_STACK_HIGH)
-#else
-  #define PER_CPU_END_STACK \
-    CPU_PER_CPU_CONTROL_SIZE
-#endif
+#define PER_CPU_INTERRUPT_STACK_LOW \
+  CPU_PER_CPU_CONTROL_SIZE
+#define PER_CPU_INTERRUPT_STACK_HIGH \
+  PER_CPU_INTERRUPT_STACK_LOW + CPU_SIZEOF_POINTER
+
+#define INTERRUPT_STACK_LOW \
+  (SYM(_Per_CPU_Information) + PER_CPU_INTERRUPT_STACK_LOW)
+#define INTERRUPT_STACK_HIGH \
+  (SYM(_Per_CPU_Information) + PER_CPU_INTERRUPT_STACK_HIGH)
 
 /*
  *  These are the offsets of the required elements in the per CPU table.
  */
 #define PER_CPU_ISR_NEST_LEVEL \
-  PER_CPU_END_STACK
+  PER_CPU_INTERRUPT_STACK_HIGH + CPU_SIZEOF_POINTER
 #define PER_CPU_ISR_DISPATCH_DISABLE \
   PER_CPU_ISR_NEST_LEVEL + 4
 #define PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL \