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.

1 files changed, 7 insertions, 86 deletions

diff --git a/cpukit/score/cpu/no_cpu/include/rtems/score/cpu.h b/cpukit/score/cpu/no_cpu/include/rtems/score/cpu.h
index c843e2661a..2cbad57843 100644
--- a/cpukit/score/cpu/no_cpu/include/rtems/score/cpu.h
+++ b/cpukit/score/cpu/no_cpu/include/rtems/score/cpu.h
@@ -46,35 +46,6 @@ extern "C" {
 /* conditional compilation parameters */
 
 /**
- * Does RTEMS manage a dedicated interrupt stack in software?
- *
- * If TRUE, then a stack is allocated in @ref _ISR_Handler_initialization.
- * If FALSE, nothing is done.
- *
- * If the CPU supports a dedicated interrupt stack in hardware,
- * then it is generally the responsibility of the BSP to allocate it
- * and set it up.
- *
- * If the CPU does not support a dedicated interrupt stack, then
- * the porter has two options: (1) execute interrupts on the
- * stack of the interrupted task, and (2) have RTEMS manage a dedicated
- * interrupt stack.
- *
- * If this is TRUE, @ref CPU_ALLOCATE_INTERRUPT_STACK should also be TRUE.
- *
- * Only one of @ref CPU_HAS_SOFTWARE_INTERRUPT_STACK and
- * @ref CPU_HAS_HARDWARE_INTERRUPT_STACK should be set to TRUE.  It is
- * possible that both are FALSE for a particular CPU.  Although it
- * is unclear what that would imply about the interrupt processing
- * procedure on that CPU.
- *
- * Port Specific Information:
- *
- * XXX document implementation including references if appropriate
- */
-#define CPU_HAS_SOFTWARE_INTERRUPT_STACK FALSE
-
-/**
  * Does the CPU follow the simple vectored interrupt model?
  *
  * If TRUE, then RTEMS allocates the vector table it internally manages.
@@ -88,40 +59,6 @@ extern "C" {
 #define CPU_SIMPLE_VECTORED_INTERRUPTS TRUE
 
 /**
- * Does this CPU have hardware support for a dedicated interrupt stack?
- *
- * If TRUE, then it must be installed during initialization.
- * If FALSE, then no installation is performed.
- *
- * If this is TRUE, @ref CPU_ALLOCATE_INTERRUPT_STACK should also be TRUE.
- *
- * Only one of @ref CPU_HAS_SOFTWARE_INTERRUPT_STACK and
- * @ref CPU_HAS_HARDWARE_INTERRUPT_STACK should be set to TRUE.  It is
- * possible that both are FALSE for a particular CPU.  Although it
- * is unclear what that would imply about the interrupt processing
- * procedure on that CPU.
- *
- * Port Specific Information:
- *
- * XXX document implementation including references if appropriate
- */
-#define CPU_HAS_HARDWARE_INTERRUPT_STACK TRUE
-
-/**
- * Does RTEMS allocate a dedicated interrupt stack in the Interrupt Manager?
- *
- * If TRUE, then the memory is allocated during initialization.
- * If FALSE, then the memory is allocated during initialization.
- *
- * This should be TRUE is CPU_HAS_SOFTWARE_INTERRUPT_STACK is TRUE.
- *
- * Port Specific Information:
- *
- * XXX document implementation including references if appropriate
- */
-#define CPU_ALLOCATE_INTERRUPT_STACK TRUE
-
-/**
  * Does the RTEMS invoke the user's ISR with the vector number and
  * a pointer to the saved interrupt frame (1) or just the vector
  * number (0)?
@@ -521,16 +458,13 @@ extern Context_Control_fp _CPU_Null_fp_context;
 /**
  * @defgroup CPUInterrupt Processor Dependent Interrupt Management
  *
- * On some CPUs, RTEMS supports a software managed interrupt stack.
- * This stack is allocated by the Interrupt Manager and the switch
- * is performed in @ref _ISR_Handler.  These variables contain pointers
- * to the lowest and highest addresses in the chunk of memory allocated
- * for the interrupt stack.  Since it is unknown whether the stack
- * grows up or down (in general), this give the CPU dependent
- * code the option of picking the version it wants to use.
- *
- * NOTE: These two variables are required if the macro
- *       @ref CPU_HAS_SOFTWARE_INTERRUPT_STACK is defined as TRUE.
+ * RTEMS supports a software managed interrupt stack.  The interrupt stacks
+ * are statically allocated by <rtems/confdefs.h> and the switch is performed
+ * by hardware or the interrupt processing code.  These variables contain
+ * pointers to the lowest and highest addresses in the chunk of memory
+ * allocated for the interrupt stack.  Since it is unknown whether the stack
+ * grows up or down (in general), this give the CPU dependent code the option
+ * of picking the version it wants to use.
  *
  * Port Specific Information:
  *
@@ -1126,19 +1060,6 @@ void _CPU_ISR_install_vector(
 );
 
 /**
- * @ingroup CPUInterrupt
- * This routine installs the hardware interrupt stack pointer.
- *
- * NOTE:  It need only be provided if @ref CPU_HAS_HARDWARE_INTERRUPT_STACK
- *        is TRUE.
- *
- * Port Specific Information:
- *
- * XXX document implementation including references if appropriate
- */
-void _CPU_Install_interrupt_stack( void );
-
-/**
  * This routine is the CPU dependent IDLE thread body.
  *
  * NOTE:  It need only be provided if @ref CPU_PROVIDES_IDLE_THREAD_BODY