树莓派编译uboot及内核

为了实验ebpf，需要自己编译内核开启相关选项，正好手头有树莓派的板子，所以正好用上。

更换内核

首先我自己用官方工具在sd卡上烧录了64位无桌面的系统，然后按照官方的文档，进行了内核的交叉编译，更换后使用uname -a发现确实更换成功了。wsl2挂载sd卡，折腾了好久，详见WSL2简单探索
挂载sd卡:

#!/bin/bashsudo mkdir -p /mnt
sudo mkdir -p /mnt/fat32
sudo mkdir -p /mnt/ext4
sudo mount /dev/sdd1 /mnt/fat32
sudo mount /dev/sdd2 /mnt/ext4

卸载sd卡

#!/bin/bashsudo umount /mnt/fat32
sudo umount /mnt/ext4

编译:

#!/bin/bashKERNEL=kernel8
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bcm2711_defconfig
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- Image modules dtbs -j12

安装:

#!/bin/bash
root=/mnt
bootfs=${root}/fat32
rootfs=${root}/ext4
sudo env PATH=$PATH make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- INSTALL_MOD_PATH=${rootfs} modules_install
#sudo mkdir -p ${bootfs}
#sudo mkdir -p ${bootfs}/overlays/
sudo cp arch/arm64/boot/Image ${bootfs}/kernel-myconfig.img
sudo cp arch/arm64/boot/dts/broadcom/*.dtb ${bootfs}/
sudo cp arch/arm64/boot/dts/overlays/*.dtb* ${bootfs}/overlays/
sudo cp arch/arm64/boot/dts/overlays/README ${bootfs}/overlays/
#tar -acvf output.tar.gz output/
#sudo scp output.tar.gz pi@link.local:/home/pi

安装uboot使用tftp升级。

使用以下脚本编译一次成功

#!/bin/bash
ARCH=arm64
CROSS_COMPILE=aarch64-linux-gnu-
make rpi_3_defconfig
make -j 12

config.h的配置，最主要的可能是这一句。

kernel=u-boot.bin

然而编好改完启动不起来，怀疑是配置有问题，但是看了官方文档，确认64位 3b的板子就是这个defconfig.
重新编译另一个defconfig，成功加载。

#!/bin/bash
export ARCH=arm64
export CROSS_COMPILE=aarch64-linux-gnu-
#make rpi_3_defconfig
make rpi_arm64_defconfig
make -j 12

最终uboot能成功加载，并且从sd卡启动系统成功:

U-Boot> help
?         - alias for 'help'
...
fatload   - load binary file from a dos filesystem
fatls     - list files in a directory (default /)
mmc       - MMC sub system
U-Boot> mmc partPartition Map for MMC device 0  --   Partition Type: DOSPart    Start Sector    Num Sectors     UUID            Type1     8192            524288          95d33193-01     0c2     532480          61988864        95d33193-02     83
U-Boot> fatls mmc 0:1 overlays/29707   bcm2710-rpi-2-b.dtb18693   COPYING.linux1594   LICENCE.broadcom145   issue.txt 
...52476   bootcode.bin131   cmdline.txt2217   config.txt
...8219600   kernel8.img624640   u-boot.bin
...21590528   kernel-myconfig.img
41 file(s), 4 dir(s)U-Boot> fatload mmc 0:1 ${kernel_addr_r} kernel-myconfig.img
21590528 bytes read in 903 ms (22.8 MiB/s)
U-Boot> booti ${kernel_addr_r} - ${fdt_addr}
Moving Image from 0x80000 to 0x200000, end=17e0000
## Flattened Device Tree blob at 2eff7f00Booting using the fdt blob at 0x2eff7f00
Working FDT set to 2eff7f00Using Device Tree in place at 000000002eff7f00, end 000000002f002ffe
Working FDT set to 2eff7f00