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, 0 insertions, 73 deletions

diff --git a/cpukit/score/cpu/v850/cpu_asm.S b/cpukit/score/cpu/v850/cpu_asm.S
index 328c71cea2..e9aa738d13 100644
--- a/cpukit/score/cpu/v850/cpu_asm.S
+++ b/cpukit/score/cpu/v850/cpu_asm.S
@@ -138,76 +138,3 @@ restore:
 __CPU_Context_restore:
         mov      r6, r7         /* move to second parameter register */
         br       restore
-
-#if 0
-/**
- *  This routine provides the RTEMS interrupt management.
- *
- *  v850 Specific Information:
- *
- *  XXX document implementation including references if appropriate
- */
-void _ISR_Handler(void); /* C warning avoidance */
-void _ISR_Handler(void)
-{
-   /*
-    *  This discussion ignores a lot of the ugly details in a real
-    *  implementation such as saving enough registers/state to be
-    *  able to do something real.  Keep in mind that the goal is
-    *  to invoke a user's ISR handler which is written in C and
-    *  uses a certain set of registers.
-    *
-    *  Also note that the exact order is to a large extent flexible.
-    *  Hardware will dictate a sequence for a certain subset of
-    *  _ISR_Handler while requirements for setting
-    */
-
-  /*
-   *  At entry to "common" _ISR_Handler, the vector number must be
-   *  available.  On some CPUs the hardware puts either the vector
-   *  number or the offset into the vector table for this ISR in a
-   *  known place.  If the hardware does not give us this information,
-   *  then the assembly portion of RTEMS for this port will contain
-   *  a set of distinct interrupt entry points which somehow place
-   *  the vector number in a known place (which is safe if another
-   *  interrupt nests this one) and branches to _ISR_Handler.
-   *
-   *  save some or all context on stack
-   *  may need to save some special interrupt information for exit
-   *
-   *  #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE )
-   *    if ( _ISR_Nest_level == 0 )
-   *      switch to software interrupt stack
-   *  #endif
-   *
-   *  _ISR_Nest_level++;
-   *
-   *  _Thread_Dispatch_disable_level++;
-   *
-   *  (*_ISR_Vector_table[ vector ])( vector );
-   *
-   *  _Thread_Dispatch_disable_level--;
-   *
-   *  --_ISR_Nest_level;
-   *
-   *  if ( _ISR_Nest_level )
-   *    goto the label "exit interrupt (simple case)"
-   *
-   *  if ( _Thread_Dispatch_disable_level )
-   *    goto the label "exit interrupt (simple case)"
-   *
-   *  if ( _Thread_Dispatch_necessary ) {
-   *    call _Thread_Dispatch() or prepare to return to _ISR_Dispatch
-   *    prepare to get out of interrupt
-   *    return from interrupt  (maybe to _ISR_Dispatch)
-   *
-   *  LABEL "exit interrupt (simple case):
-   *  #if ( CPU_HAS_SOFTWARE_INTERRUPT_STACK == TRUE )
-   *    if outermost interrupt
-   *      restore stack
-   *  #endif
-   *  prepare to get out of interrupt
-   *  return from interrupt
-   */
-}
-#endif