mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-09-09 06:13:21 +09:00
334 lines
6.3 KiB
ArmAsm
334 lines
6.3 KiB
ArmAsm
/*
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* armboot - Startup Code for ARM720 CPU-core
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*
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* Copyright (c) 2001 Marius Gröger <mag@sysgo.de>
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* Copyright (c) 2002 Alex Züpke <azu@sysgo.de>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <asm-offsets.h>
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#include <config.h>
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#include <version.h>
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#include <asm/hardware.h>
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/*
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*************************************************************************
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*
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* Jump vector table as in table 3.1 in [1]
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*
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*************************************************************************
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*/
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.globl _start
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_start: b reset
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ldr pc, _undefined_instruction
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ldr pc, _software_interrupt
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ldr pc, _prefetch_abort
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ldr pc, _data_abort
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ldr pc, _not_used
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ldr pc, _irq
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ldr pc, _fiq
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#ifdef CONFIG_SPL_BUILD
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_undefined_instruction: .word _undefined_instruction
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_software_interrupt: .word _software_interrupt
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_prefetch_abort: .word _prefetch_abort
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_data_abort: .word _data_abort
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_not_used: .word _not_used
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_irq: .word _irq
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_fiq: .word _fiq
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_pad: .word 0x12345678 /* now 16*4=64 */
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#else
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_undefined_instruction: .word undefined_instruction
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_software_interrupt: .word software_interrupt
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_prefetch_abort: .word prefetch_abort
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_data_abort: .word data_abort
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_not_used: .word not_used
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_irq: .word irq
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_fiq: .word fiq
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_pad: .word 0x12345678 /* now 16*4=64 */
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#endif /* CONFIG_SPL_BUILD */
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.balignl 16,0xdeadbeef
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/*
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*************************************************************************
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*
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* Startup Code (reset vector)
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*
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* do important init only if we don't start from RAM!
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* relocate armboot to ram
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* setup stack
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* jump to second stage
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*
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*************************************************************************
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*/
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.globl _TEXT_BASE
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_TEXT_BASE:
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#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_TEXT_BASE)
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.word CONFIG_SPL_TEXT_BASE
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#else
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.word CONFIG_SYS_TEXT_BASE
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#endif
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/*
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* These are defined in the board-specific linker script.
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* Subtracting _start from them lets the linker put their
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* relative position in the executable instead of leaving
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* them null.
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*/
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.globl _bss_start_ofs
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_bss_start_ofs:
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.word __bss_start - _start
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.globl _bss_end_ofs
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_bss_end_ofs:
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.word __bss_end - _start
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.globl _end_ofs
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_end_ofs:
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.word _end - _start
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#ifdef CONFIG_USE_IRQ
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/* IRQ stack memory (calculated at run-time) */
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.globl IRQ_STACK_START
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IRQ_STACK_START:
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.word 0x0badc0de
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/* IRQ stack memory (calculated at run-time) */
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.globl FIQ_STACK_START
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FIQ_STACK_START:
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.word 0x0badc0de
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#endif
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/* IRQ stack memory (calculated at run-time) + 8 bytes */
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.globl IRQ_STACK_START_IN
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IRQ_STACK_START_IN:
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.word 0x0badc0de
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/*
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* the actual reset code
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*/
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reset:
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/*
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* set the cpu to SVC32 mode
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*/
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mrs r0,cpsr
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bic r0,r0,#0x1f
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orr r0,r0,#0xd3
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msr cpsr,r0
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/*
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* we do sys-critical inits only at reboot,
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* not when booting from ram!
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*/
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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bl cpu_init_crit
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#endif
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bl _main
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/*------------------------------------------------------------------------------*/
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.globl c_runtime_cpu_setup
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c_runtime_cpu_setup:
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mov pc, lr
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/*
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*************************************************************************
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*
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* CPU_init_critical registers
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*
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* setup important registers
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* setup memory timing
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*
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*************************************************************************
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*/
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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cpu_init_crit:
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mov ip, lr
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/*
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* before relocating, we have to setup RAM timing
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* because memory timing is board-dependent, you will
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* find a lowlevel_init.S in your board directory.
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*/
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bl lowlevel_init
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mov lr, ip
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mov pc, lr
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#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
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#ifndef CONFIG_SPL_BUILD
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/*
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*************************************************************************
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*
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* Interrupt handling
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*
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*************************************************************************
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*/
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@
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@ IRQ stack frame.
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@
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#define S_FRAME_SIZE 72
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#define S_OLD_R0 68
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#define S_PSR 64
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#define S_PC 60
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#define S_LR 56
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#define S_SP 52
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#define S_IP 48
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#define S_FP 44
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#define S_R10 40
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#define S_R9 36
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#define S_R8 32
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#define S_R7 28
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#define S_R6 24
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#define S_R5 20
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#define S_R4 16
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#define S_R3 12
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#define S_R2 8
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#define S_R1 4
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#define S_R0 0
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#define MODE_SVC 0x13
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#define I_BIT 0x80
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/*
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* use bad_save_user_regs for abort/prefetch/undef/swi ...
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* use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
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*/
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.macro bad_save_user_regs
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sub sp, sp, #S_FRAME_SIZE
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stmia sp, {r0 - r12} @ Calling r0-r12
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add r8, sp, #S_PC
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ldr r2, IRQ_STACK_START_IN
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ldmia r2, {r2 - r4} @ get pc, cpsr, old_r0
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add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
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add r5, sp, #S_SP
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mov r1, lr
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stmia r5, {r0 - r4} @ save sp_SVC, lr_SVC, pc, cpsr, old_r
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mov r0, sp
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.endm
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.macro irq_save_user_regs
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sub sp, sp, #S_FRAME_SIZE
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stmia sp, {r0 - r12} @ Calling r0-r12
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add r8, sp, #S_PC
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stmdb r8, {sp, lr}^ @ Calling SP, LR
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str lr, [r8, #0] @ Save calling PC
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mrs r6, spsr
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str r6, [r8, #4] @ Save CPSR
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str r0, [r8, #8] @ Save OLD_R0
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mov r0, sp
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.endm
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.macro irq_restore_user_regs
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ldmia sp, {r0 - lr}^ @ Calling r0 - lr
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mov r0, r0
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ldr lr, [sp, #S_PC] @ Get PC
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add sp, sp, #S_FRAME_SIZE
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subs pc, lr, #4 @ return & move spsr_svc into cpsr
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.endm
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.macro get_bad_stack
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ldr r13, IRQ_STACK_START_IN @ setup our mode stack
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str lr, [r13] @ save caller lr / spsr
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mrs lr, spsr
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str lr, [r13, #4]
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mov r13, #MODE_SVC @ prepare SVC-Mode
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msr spsr_c, r13
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mov lr, pc
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movs pc, lr
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.endm
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.macro get_irq_stack @ setup IRQ stack
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ldr sp, IRQ_STACK_START
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.endm
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.macro get_fiq_stack @ setup FIQ stack
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ldr sp, FIQ_STACK_START
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.endm
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/*
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* exception handlers
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*/
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.align 5
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undefined_instruction:
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get_bad_stack
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bad_save_user_regs
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bl do_undefined_instruction
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.align 5
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software_interrupt:
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get_bad_stack
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bad_save_user_regs
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bl do_software_interrupt
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.align 5
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prefetch_abort:
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get_bad_stack
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bad_save_user_regs
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bl do_prefetch_abort
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.align 5
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data_abort:
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get_bad_stack
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bad_save_user_regs
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bl do_data_abort
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.align 5
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not_used:
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get_bad_stack
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bad_save_user_regs
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bl do_not_used
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#ifdef CONFIG_USE_IRQ
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.align 5
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irq:
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get_irq_stack
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irq_save_user_regs
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bl do_irq
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irq_restore_user_regs
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.align 5
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fiq:
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get_fiq_stack
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/* someone ought to write a more effiction fiq_save_user_regs */
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irq_save_user_regs
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bl do_fiq
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irq_restore_user_regs
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#else
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.align 5
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irq:
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get_bad_stack
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bad_save_user_regs
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bl do_irq
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.align 5
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fiq:
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get_bad_stack
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bad_save_user_regs
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bl do_fiq
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#endif
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#endif /* CONFIG_SPL_BUILD */
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