afb083625c
In the case that the STKALIGN bit is set on Cortex M processors, on entry to an exception - the processor can store an additional 4 bytes of padding before regular stacking to achieve 8-byte alignment on exception entry. In the case that this padding is present, the processor will set bit (1 << 9) in the stacked xPSR register. Use the new calculate_process_stack callback to take into account the xPSR register and use it on the standard Cortex_M3 stacking. Note: Change #2301 had some misinformation regarding the padding. On Cortex-M the padding is stored BEFORE stacking so xPSR is always available at a fixed offset. Tested on a Cortex-M0+ (Atmel SAMR21) board which has STKALIGN fixed to a '1' such that this alignment always occurs on non-aligned stacks. Behavior of xPSR verified via the (bad-sorry) assembly program below by setting a breakpoint on the SVC_Handler symbol. The first time SVC_Handler is triggered the stack was 0x20000ff8, the second time SVC_Handler is triggered the stack was 0x20000ffc. Note that in both cases the interrupt handler gets 0x20000fd8 for a stack pointer. GDB exerpt: Breakpoint 1, 0x000040b6 in Reset_Handler () (gdb) hbreak SVC_Handler Hardware assisted breakpoint 2 at 0x40f8 (gdb) cont Continuing. Breakpoint 2, 0x000040f8 in SVC_Handler () (gdb) print $msp $3 = (void *) 0x20000fd8 (gdb) x/9w $msp 0x20000fd8: 0x1 0x2 0x3 0x4 0x20000fe8: 0x88160082 0xa53 0x40ce 0x21000000 0x20000ff8: 0x0 (gdb) cont Continuing. Breakpoint 2, 0x000040f8 in SVC_Handler () (gdb) print $msp $4 = (void *) 0x20000fd8 (gdb) x/9w $msp 0x20000fd8: 0x1 0x2 0x3 0x4 0x20000fe8: 0x88160082 0xa53 0x40e8 0x21000200 0x20000ff8: 0x0 Assembly program: .cpu cortex-m0plus .fpu softvfp .thumb .syntax unified .section .vectors @ pvStack: .word 0x20001000 @ pfnReset_Handler: .word Reset_Handler + 1 @ pfnNMI_Handler: .word 0 @ pfnHardFault_Handler: .word 0 @ pfnReservedM12: .word 0 @ pfnReservedM11: .word 0 @ pfnReservedM10: .word 0 @ pfnReservedM9: .word 0 @ pfnReservedM8: .word 0 @ pfnReservedM7: .word 0 @ pfnReservedM6: .word 0 @ pfnSVC_Handler: .word SVC_Handler + 1 .section .text .global Reset_Handler Reset_Handler: cpsie i ldr r0, .stack_start ldr r2, .stack_last eors r1, r1 .loop_clear: str r1, [r0] adds r0, r0, #4 cmp r0, r2 bne .loop_clear subs r2, r2, #4 mov sp, r2 movs r0, #1 movs r1, #2 movs r2, #3 movs r3, #4 svc #0 ldr r0, .stack_start ldr r2, .stack_last eors r1, r1 .loop_clear2: str r1, [r0] adds r0, r0, #4 cmp r0, r2 bne .loop_clear2 mov sp, r2 movs r0, #1 movs r1, #2 movs r2, #3 movs r3, #4 svc #0 .loop: b .loop .align 4 .stack_start: .word 0x20000f00 .stack_last: .word 0x20000ffc @ first call - 0x2000fff8 -- should already be aligned @ second call - 0x2000fffc -- should hit the alignment code .global SVC_Handler SVC_Handler: bx lr Change-Id: Id0940e6bbd6a59adee1378c0e86fe86830f0c8fc Signed-off-by: Andrew Ruder <andrew.ruder@elecsyscorp.com> Cc: Paul Fertser <fercerpav@gmail.com> Cc: Andreas Fritiofson <andreas.fritiofson@gmail.com> Cc: Evan Hunter <evanhunter920@gmail.com> Cc: Jon Burgess <jburgess777@gmail.com> Reviewed-on: http://openocd.zylin.com/3003 Tested-by: jenkins Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>
41 lines
2.2 KiB
C
41 lines
2.2 KiB
C
/***************************************************************************
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* Copyright (C) 2011 by Broadcom Corporation *
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* Evan Hunter - ehunter@broadcom.com *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, write to the *
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* Free Software Foundation, Inc., *
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
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***************************************************************************/
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#ifndef INCLUDED_RTOS_STANDARD_STACKINGS_H_
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#define INCLUDED_RTOS_STANDARD_STACKINGS_H_
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "rtos.h"
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extern const struct rtos_register_stacking rtos_standard_Cortex_M3_stacking;
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extern const struct rtos_register_stacking rtos_standard_Cortex_R4_stacking;
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extern const struct rtos_register_stacking rtos_standard_NDS32_N1068_stacking;
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int64_t rtos_generic_stack_align8(struct target *target,
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const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
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int64_t stack_ptr);
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int64_t rtos_Cortex_M_stack_align(struct target *target,
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const uint8_t *stack_data, const struct rtos_register_stacking *stacking,
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int64_t stack_ptr, size_t xpsr_offset);
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#endif /* ifndef INCLUDED_RTOS_STANDARD_STACKINGS_H_ */
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