Докладчик покажет, как с помощью bare-metal programming подружить Raspberry Pi с GPIO, памятью и Ethernet, и пояснит, кому и зачем это может понадобиться.

1. Bare-metal programming на
примере Raspberry Pi
10/03/2017
DCG #7812
г. Санкт-Петербург

2. Who am i
Ранее:
• DC4919;
• Bushwhackers;
• BalalaikaCr3w.
Сейчас:
• Evil Dwarfs;
• Безопасность АСУ ТП;
• OWASP Russia;
• jbfc;
• It sec pro course;
• ASP Labs.
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3. Bare-metal
• Обучение
http://www.cl.cam.ac.uk/freshers/raspberr
ypi/tutorials/
http://wiki.osdev.org/Raspberry_Pi_Bare_Bo
nes
• Производительность
• For fun!
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4. Raspberry pi
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5. Why raspberry pi
• дёшево
• много материалов (-RP 3)
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6. CPU
RPi:
• ARM1176GTZF
RPi 2:
• Cortex A7
RPi 3:
• Cortex A53(Aarch-64)
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7. CPU
RPi:
• arm-none-eabi-gcc -O2 -mfpu=vfp -mfloat-
abi=hard -march=armv6zk -mtune=arm1176jzf-s
arm-test.c
RPi 2:
• arm-none-eabi-gcc -O2 -mfpu=vfp -mfloat-
abi=hard -march=armv7-a -mtune=cortex-a7 arm-
test.c
RPi 3:
• aarch64-elf-gcc (linaro cross gcc)
(https://releases.linaro.org/components/toolchain/binaries/6.1-
2016.08/aarch64-elf/ )
*arm-none-eabi-objcopy kernel.elf -O binary kernel.img
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8. Cortex A53
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9. How it works
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RAM 0
X00000000
-------------------
IO
0x3f0000000
or
0x20000000
-------------------
GPIO
0x3f0200000
or
0x20200000
-------------------
...
GPU
CPU

10. Steps
1. Start GPU
– Read SD
2. CPU
– bootload.bin, start.elf, config
3. Start CPU cores
– Run Kernel.img
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11. Files
1. bootloader.bin
загружает start.elf
2. start.elf
прошивка GPU которая стартует CPU
3. config.txt
конфигурация
4. kernel.img
OS или ваша программа
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12. config.txt
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Examples:
arm_control=0x200 (запуск в x64)
kernel_old=1 (загрузка с 0)
disable_commandline_tags=1
kernel_old=1
disable_commandline_tags=1
kernel_address=0x06000000

13. Other files
https://github.com/raspberrypi/firmware
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14. GPIO
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https://rawgit.com/msperl/rpi-registers/master/rpi-registers.html

15. UART
Examples:
https://github.com/gingold-adacore/rpi3-
fosdem17
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16. Blink
Examples:
http://www.valvers.com/open-
software/raspberry-pi/step01-bare-metal-
programming-in-cpt1/ (RPI, RPI 2)
https://github.com/dwelch67/raspberrypi
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17. Wanna more
Examples:
https://github.com/PeterLemon/RaspberryPi
https://www.raspberrypi.org/forums/viewtopic.
php?t=72260
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18. USB
Examples:
https://github.com/rsta2/uspi
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19. Free SCADA
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20. Q?
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