mirror of
https://github.com/fergalmoran/ladybird.git
synced 2025-12-31 13:48:25 +00:00
d0c1db5efc
After building and running
objcopy -O binary Build/aarch64/Kernel/Prekernel/Prekernel \
/media/sdcard/kernel8.img
things start booting on an actual RPi4 :^)
(Assuming the sdcard contains RPi firmware, an empty config.txt,
and no other kernel*.img files).
43 lines
987 B
ArmAsm
43 lines
987 B
ArmAsm
/*
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* Copyright (c) 2021, Nico Weber <thakis@chromium.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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// In a specially-named text section so that the linker script can put it first in .text.
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.section ".text.first"
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.global start
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.type start, @function
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start:
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// Let only core 0 continue, put other cores to sleep.
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mrs x13, MPIDR_EL1
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and x13, x13, 0xff
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cbnz x13, halt
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// Let stack start before .text for now.
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// 512 kiB (0x80000) of stack are probably not sufficient, especially once we give the other cores some stack too,
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// but for now it's ok.
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ldr x14, =start
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mov sp, x14
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// Clear BSS.
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ldr x14, =start_of_bss
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ldr x15, =size_of_bss_divided_by_8
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Lbss_clear_loop:
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str xzr, [x14], #8
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subs x15, x15, #1
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bne Lbss_clear_loop
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b init
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.globl wait_cycles
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.type wait_cycles, @function
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wait_cycles:
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Lstart:
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// This is probably too fast when caching and branch prediction is turned on.
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// FIXME: Make timer-based.
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subs x0, x0, #1
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bne Lstart
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ret
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