86 lines
1.4 KiB
ArmAsm
86 lines
1.4 KiB
ArmAsm
/*
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* \brief Startup code for bootstrap
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* \author Stefan Kalkowski
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* \date 2019-05-11
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*/
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/*
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* Copyright (C) 2019 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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.section ".text.crt0"
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.global _start
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_start:
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/***********************
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** Detect CPU number **
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***********************/
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mrs x0, mpidr_el1
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and x0, x0, #0b11111111
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cbz x0, _crt0_fill_bss_zero
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/**
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* Hack for Qemu, which starts all cpus at once
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*/
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1:
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ldr x1, =_crt0_qemu_start_secondary_cpus
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ldr w1, [x1]
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cbnz w1, _crt0_enable_fpu
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wfe
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b 1b
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.global _crt0_qemu_start_secondary_cpus
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_crt0_qemu_start_secondary_cpus:
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.long 0
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/***************************
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** Zero-fill BSS segment **
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***************************/
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_crt0_fill_bss_zero:
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ldr x1, =_bss_start
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ldr x2, =_bss_end
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1:
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cmp x2, x1
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b.eq _crt0_enable_fpu
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str xzr, [x1], #8
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b 1b
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/****************
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** Enable FPU **
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****************/
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.global _crt0_enable_fpu
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_crt0_enable_fpu:
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mov x1, #0b11
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lsl x1, x1, #20
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msr cpacr_el1, x1
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/**********************
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** Initialize stack **
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**********************/
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.set STACK_SIZE, 0x2000
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ldr x1, =_crt0_start_stack
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ldr x2, [x1]
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mul x0, x0, x2
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add x1, x1, x0
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mov sp, x1
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bl init
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.p2align 4
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.rept NR_OF_CPUS
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.space STACK_SIZE
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.endr
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_crt0_start_stack:
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.long STACK_SIZE
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