Files
rtems/bsps/lm32/shared/start/start.S
Sebastian Huber 511dc4b2be 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.
2018-06-27 08:58:16 +02:00

161 lines
2.5 KiB
ArmAsm

/* LM32 startup code
*
* This is the entry point on reset and when loading the
* executive from a bootloader.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*
* Jukka Pietarinen <jukka.pietarinen@mrf.fi>, 2008,
* Micro-Research Finland Oy
*/
#include "bspopts.h"
.section .boot,"a",@progbits
.align 4
.globl start
.type start,@function
.globl _start
.type _start,@function
.globl __start
.type __start,@function
.globl LatticeDDInit
.type LatticeDDInit,@function
.globl crt0
.type crt0,@function
LatticeDDInit:
__start:
_start:
start:
/* Clear r0 */
xor r0,r0,r0
/* Disable interrupts */
wcsr IE, r0
/* Mask all interrupts */
wcsr IM,r0
/* Set exception base address */
mvhi r1, hi(start)
ori r1, r1, lo(start)
wcsr EBA, r1
bi crt0
nop
/*
* Unused handlers call debug handlers
*/
breakpoint_handler:
rcsr r7, DEBA
addi r7, r7, 32
b r7
nop
nop
nop
nop
nop
instruction_bus_error_handler:
rcsr r7, DEBA
addi r7, r7, 64
b r7
nop
nop
nop
nop
nop
watchpoint_handler:
rcsr r7, DEBA
addi r7, r7, 96
b r7
nop
nop
nop
nop
nop
data_bus_error_handler:
rcsr r7, DEBA
addi r7, r7, 128
b r7
nop
nop
nop
nop
nop
divide_by_zero_handler:
rcsr r7, DEBA
addi r7, r7, 160
b r7
nop
nop
nop
nop
nop
interrupt_handler:
.extern _ISR_Handler
mvhi r0, hi(_ISR_Handler)
ori r0, r0, lo(_ISR_Handler)
b r0
nop
nop
nop
nop
nop
system_call_handler:
rcsr r7, DEBA
addi r7, r7, 224
b r7
nop
nop
nop
nop
nop
crt0:
/* Flush data cache */
addi r1, r0, 1
wcsr DCC, r1
nop
nop
nop
nop
/* Flush Instruction Cache */
wcsr ICC, r1
nop
nop
nop
nop
/* Initialize stack pointer */
mvhi sp, hi(_Configuration_Interrupt_stack_area_end-4)
ori sp, sp, lo(_Configuration_Interrupt_stack_area_end-4)
/* Initialize global pointer */
mvhi gp, hi(_edata)
ori gp, gp, lo(_edata)
/* Clear bss */
mvhi r1, hi(_clear_start)
ori r1, r1, lo(_clear_start)
mvhi r3, hi(_clear_end)
ori r3, r3, lo(_clear_end)
.clear_bss:
be r1, r3, .end_clear_bss
sw (r1+0), r0
addi r1, r1, 4
bi .clear_bss
.end_clear_bss:
mvi r1, 0
be r4, r0, .no_rescue
mvhi r1, hi(.rescue_str)
ori r1, r1, lo(.rescue_str)
.no_rescue:
mvhi r7, hi(boot_card)
ori r7, r7, lo(boot_card)
call r7
# boot_card returns when RTEMS is shutdown
.dead_end:
bi .dead_end
.section .rodata
.rescue_str:
.ascii "rescue"