Используя ответ, предоставленный Питером Мэйделлом , я приведу здесь минимальный воспроизводимый пример для людей, которые могут быть заинтересованы.
Загрузка / установка набора инструментов aarch64-elf:
wget "https://developer.arm.com/-/media/Files/downloads/gnu-a/8.3-2019.03/binrel/gcc-arm-8.3-2019.03-x86_64-aarch64-elf.tar.xz?revision=d678fd94-0ac4-485a-8054-1fbc60622a89&la=en"
mkdir -p /opt/arm
tar Jxf gcc-arm-8.3-2019.03-x86_64-aarch64-elf.tar.xz -C /opt/arm
Файлы примеров:
loop.s:
.title "loop.s"
.arch armv8-a
.text
.global Reset_Handler
Reset_Handler: mrs x0, mpidr_el1
and x0,x0, 0b11
cmp x0, #0
b.eq Core0
cmp x0, #1
b.eq Core1
cmp x0, #2
b.eq Core2
cmp x0, #3
b.eq Core3
Error: b .
Core0: b .
Core1: b .
Core2: b .
Core3: b .
.end
build.sh:
#!/bin/bash
set -e
CROSS_COMPILE=/opt/arm/gcc-arm-8.3-2019.03-x86_64-aarch64-elf/bin/aarch64-elf-
AS=${CROSS_COMPILE}as
LD=${CROSS_COMPILE}ld
OBJCOPY=${CROSS_COMPILE}objcopy
OBJDUMP=${CROSS_COMPILE}objdump
${AS} -g -o loop.o loop.s
${LD} -g -gc-sections -g -e Reset_Handler -Ttext-segment=0x40004000 -Map=loop.map -o loop.elf loop.o
${OBJDUMP} -d loop.elf
qemu.sh:
#!/bin/bash
set -e
QEMU_SYSTEM_AARCH64=qemu-system-aarch64
${QEMU_SYSTEM_AARCH64} \
-s -S \
-machine virt,secure=on,virtualization=on \
-cpu cortex-a53 \
-d int \
-m 512M \
-smp 4 \
-display none \
-nographic \
-semihosting \
-serial mon:stdio \
-bios loop.elf \
-device loader,addr=0x40004000,cpu-num=0 \
-device loader,addr=0x40004000,cpu-num=1 \
-device loader,addr=0x40004000,cpu-num=2 \
-device loader,addr=0x40004000,cpu-num=3 \
;
loop.gdb:
target remote localhost:1234
file loop.elf
load loop.elf
disassemble Reset_Handler
info threads
continue
debug.sh:
#!/bin/bash
CROSS_COMPILE=/opt/arm/gcc-arm-8.3-2019.03-x86_64-aarch64-elf/bin/aarch64-elf-
GDB=${CROSS_COMPILE}gdb
${GDB} --command=loop.gdb
Выполнение программы - понадобятся две консоли.
Перваяконсоль:
./build.sh
Вывод должен выглядеть следующим образом:
/opt/arm/gcc-arm-8.3-2019.03-x86_64-aarch64-elf/bin/aarch64-elf-ld: warning: address of `text-segment' isn't multiple of maximum page size
loop.elf: file format elf64-littleaarch64
Disassembly of section .text:
0000000040004000 <Reset_Handler>:
40004000: d53800a0 mrs x0, mpidr_el1
40004004: 92400400 and x0, x0, #0x3
40004008: f100001f cmp x0, #0x0
4000400c: 54000100 b.eq 4000402c <Core0> // b.none
40004010: f100041f cmp x0, #0x1
40004014: 540000e0 b.eq 40004030 <Core1> // b.none
40004018: f100081f cmp x0, #0x2
4000401c: 540000c0 b.eq 40004034 <Core2> // b.none
40004020: f1000c1f cmp x0, #0x3
40004024: 540000a0 b.eq 40004038 <Core3> // b.none
0000000040004028 <Error>:
40004028: 14000000 b 40004028 <Error>
000000004000402c <Core0>:
4000402c: 14000000 b 4000402c <Core0>
0000000040004030 <Core1>:
40004030: 14000000 b 40004030 <Core1>
0000000040004034 <Core2>:
40004034: 14000000 b 40004034 <Core2>
0000000040004038 <Core3>:
40004038: 14000000 b 40004038 <Core3>
Тогда:
./qemu.sh
Вторая консоль:
./debug.sh
Вывод долженвыглядят так:
GNU gdb (GNU Toolchain for the A-profile Architecture 8.3-2019.03 (arm-rel-8.36)) 8.2.1.20190227-git
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "--host=x86_64-pc-linux-gnu --target=aarch64-elf".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://bugs.linaro.org/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word".
warning: No executable has been specified and target does not support
determining executable automatically. Try using the "file" command.
0x0000000040004000 in ?? ()
Loading section .text, size 0x3c lma 0x40004000
Start address 0x40004000, load size 60
Transfer rate: 480 bits in <1 sec, 60 bytes/write.
Dump of assembler code for function Reset_Handler:
=> 0x0000000040004000 <+0>: mrs x0, mpidr_el1
0x0000000040004004 <+4>: and x0, x0, #0x3
0x0000000040004008 <+8>: cmp x0, #0x0
0x000000004000400c <+12>: b.eq 0x4000402c <Core0> // b.none
0x0000000040004010 <+16>: cmp x0, #0x1
0x0000000040004014 <+20>: b.eq 0x40004030 <Core1> // b.none
0x0000000040004018 <+24>: cmp x0, #0x2
0x000000004000401c <+28>: b.eq 0x40004034 <Core2> // b.none
0x0000000040004020 <+32>: cmp x0, #0x3
0x0000000040004024 <+36>: b.eq 0x40004038 <Core3> // b.none
End of assembler dump.
Id Target Id Frame
* 1 Thread 1.1 (CPU#0 [running]) Reset_Handler () at loop.s:5
2 Thread 1.2 (CPU#1 [running]) Reset_Handler () at loop.s:5
3 Thread 1.3 (CPU#2 [running]) Reset_Handler () at loop.s:5
4 Thread 1.4 (CPU#3 [running]) Reset_Handler () at loop.s:5
Все четыре ядра остановлены по адресу 0x40004000/Reset_Handler и запущены командой continue в loop.gdb. Нажмите CTRL+C во второй консоли:
^C
Thread 1 received signal SIGINT, Interrupt.
Core0 () at loop.s:16
16 Core0: b .
(gdb)
Core # 0 выполнял код на метке Core0. Введите следующую команду (все еще во второй консоли):
(gdb) info threads
Id Target Id Frame
* 1 Thread 1.1 (CPU#0 [running]) Core0 () at loop.s:16
2 Thread 1.2 (CPU#1 [running]) Core1 () at loop.s:17
3 Thread 1.3 (CPU#2 [running]) Core2 () at loop.s:18
4 Thread 1.4 (CPU#3 [running]) Core3 () at loop.s:19
(gdb)
Ядра # 1, # 2 и # 3 выполняли код на соответствующих метках Core1, Core2, Core3 до остановки CTRL+C.
Описание регистра MPIDR_EL1 доступно здесь : два последних бита MPIDR_EL1.Aff0 использовались всеми четырьмя ядрами для определения их соответствующих номеров ядер.