Timeline

2025-06-23

init

2025-11-05

busybox build error in archlinux

Environment

Win11 WSL2:

Environment

busybox Compilation

1
2
3
4
5
wget https://www.busybox.net/downloads/busybox-1.37.0.tar.bz2
bzip2 -d busybox-1.37.0.tar.bz2
tar xvf busybox-1.37.0.tar

cd busybox-1.37.0

Patch

This version has some issues when compiling directly for aarch64 — a patch is needed:

1
emacs libbb-sha-add-missing-shaNI-guard.patch

Reference:

libbb/sha: add missing sha-NI guard

https://lists.busybox.net/pipermail/busybox/2024-September/090899.html

The patch is as follows:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
---
 libbb/hash_md5_sha.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libbb/hash_md5_sha.c b/libbb/hash_md5_sha.c
index 57a801459..75a61c32c 100644
--- a/libbb/hash_md5_sha.c
+++ b/libbb/hash_md5_sha.c
@@ -1313,7 +1313,9 @@ unsigned FAST_FUNC sha1_end(sha1_ctx_t *ctx, void *resbuf)
    hash_size = 8;
    if (ctx->process_block == sha1_process_block64
 #if ENABLE_SHA1_HWACCEL
+# if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
     || ctx->process_block == sha1_process_block64_shaNI
+# endif
 #endif
    ) {
        hash_size = 5;
--
2.25.1

Enter the busybox source directory and execute:

1
patch -p1 < libbb-sha-add-missing-shaNI-guard.patch

Compilation

1
2
3
4
5
6
7
8
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- distclean
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
# Settings
# --- Build Option
#   [*] Build static binary (no shared libs)
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j$(nproc)
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- install

make menuconfig Failure

The make menuconfig step may fail on Arch Linux or with higher GCC versions:

1
2
3
4
5
6
7
8
9
10
[zhaohang@cyberboy busybox-1.37.0]$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
 *** Unable to find the ncurses libraries or the
 *** required header files.
 *** 'make menuconfig' requires the ncurses libraries.
 ***
 *** Install ncurses (ncurses-devel) and try again.
 ***
make[2]: *** [.../scripts/kconfig/lxdialog/Makefile:15: ...] Error 1
make[1]: *** [.../scripts/kconfig/Makefile:14: menuconfig] Error 2
make: *** [Makefile:444: menuconfig] Error 2

Even with ncurses installed, it still fails:

1
sudo pacman -S ncurses

Reference solution:

Busybox build fails with ncurses header not found in archlinux

https://stackoverflow.com/questions/78491346/busybox-build-fails-with-ncurses-header-not-found-in-archlinux-spoiler-i-alrea

The discussion above notes that higher GCC versions have a breaking change — the main function must have a return type:

1
2
3
emacs scripts/kconfig/lxdialog/check-lxdialog.sh
# Change line 50: main() {} to
# int main() {return 0;}

tc Build Error

If using a higher Linux kernel version, you need to disable tc. Reference:

[Bug 15934] New: Busybox fails to build with linux kernels >= 6.8

https://lists.busybox.net/pipermail/busybox-cvs/2024-January/041752.html

Disable it in make menuconfig:

1
2
Networking Utilities  --->
    [ ] TC        # Disable

Creating inittab, rcS, and fstab Files

1
2
3
4
5
6
7
8
9
10
11
12
13
cd _install

mkdir -p dev etc home lib/modules lib64 mnt proc root sys tmp var

touch etc/inittab

mkdir -p etc/init.d/
touch etc/init.d/rcS

touch etc/fstab

chmod 755 etc/inittab
chmod 755 etc/init.d/rcS

inittab syntax:

1
<id>:<runlevels>:<action>:<process>
  • id : /dev/id
  • runlevels : ignored
  • action : when to execute — options: sysinit, respawn, askfirst, wait, once, restart, ctrlaltdel, and shutdown
  • process : application or script

etc/inittab content:

1
2
3
4
::sysinit:/etc/init.d/rcS
::respawn:-/bin/sh
::askfirst:-/bin/sh
::ctrlaltdel:/bin/umount -a -r

etc/init.d/rcS content:

1
2
3
4
5
6
7
8
/bin/mount -a
mkdir -p /dev/pts
mount -t devpts devpts /dev/pts
mount -t configfs none /sys/kernel/config
if [ -e /proc/sys/kernel/hotplug ]; then
    echo /sbin/mdev > /proc/sys/kernel/hotplug
fi
mdev -s

etc/fstab content:

1
2
3
4
5
6
#device mount-point type option dump fsck
proc  /proc proc  defaults 0 0
tmpfs /tmp tmpfs defaults 0 0
none  /tmp  ramfs defaults 0 0
sysfs /sys  sysfs defaults 0 0
mdev  /dev  ramfs defaults 0 0

Adding Device Files

1
2
3
cd dev
sudo mknod console c 5 1
sudo mknod null c 1 3

Adding Library Files

This step is optional:

1
2
3
4
cd _install
cp /usr/aarch64-linux-gnu/lib/ld-linux-aarch64.so.1 lib/
cp /usr/aarch64-linux-gnu/lib/libc.so.6 lib/
cp /usr/aarch64-linux-gnu/lib/libm.so.6 lib/

Packaging

1
2
3
cd busybox-1.37.0/_install
find . | cpio -o -H newc | gzip -c > ../initramfs.cpio.gz
cp ../initramfs.cpio.gz ~/tftp

Linux Kernel Compilation

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
sudo apt-get install gcc-aarch64-linux-gnu
sudo apt install libssl-dev

wget https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.238.tar.xz
tar xvf linux-5.10.238.tar.xz
cd linux-5.10.238
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- clean
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
# This step is needed for kernel module development, optional
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- modules_prepare
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- Image -j$(nproc)

cp arch/arm64/boot/Image ~/tftp

Emacs + clangd for Reading Linux Source Code

Create .clangd in the Linux source root:

1
2
3
CompileFlags:
  Add: -Wno-unknown-warning-option
  Remove: [-m*, -f*]

Generate compile_commands.json (requires python3):

1
./scripts/clang-tools/gen_compile_commands.py

Emacs configuration reference:

My Emacs Configuration

https://even629.com/posts/28521/

Emacs + dts-lsp for Reading Device Trees

Uses dts-lsp:

1
$ npm i -g devicetree-language-server

Create .dir-locals.el in the kernel root directory with the following content:

1
2
3
4
5
6
7
8
9
10
11
12
13
((dts-mode
  . ((eglot-workspace-configuration
      . ((devicetree
          (cwd . "/home/zhaohang/repository/linux/rk3568_linux_5.10/kernel")          
          (defaultIncludePaths . ["include"])
          (defaultBindingType . "DevicetreeOrg")
          (defaultDeviceOrgBindingsMetaSchema . ["/home/zhaohang/repository/dt-schema/dtschema/meta-schemas"])
          (defaultDeviceOrgTreeBindings . [
                                           ;; "/home/zhaohang/repository/dt-schema/dtschema/schemas"
                                           "/home/zhaohang/repository/linux/rk3568_linux_5.10/kernel/Documentation/devicetree/bindings"
                                           ])
          (defaultShowFormattingErrorAsDiagnostics . :json-false)
          ))))))

Where dt-schema comes from:

eglot configuration in Emacs:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
(use-package dts-mode
  :ensure t
  :defer t
  )

;; LSP language server configuration
(use-package eglot
  :ensure t
  :defer 1
  :config
  (setq eglot-server-programs
        '(((c-mode-hook c++-mode-hook c++-ts-mode c-ts-mode)
                                                       . ("clangd"
                                                          "--enable-config"
                                                          "--background-index"
                                                          ;; "--background-index-priority=low"
                                                          "--clang-tidy"
                                                          "--completion-style=detailed"
                                                          "--header-insertion=never"
                                                          "--pretty"
                                                          ))
          ((dts-mode)                                  . ("devicetree-language-server" "--stdio"))
          ((rust-mode rust-ts-mode)                    . ("rust-analyzer" :initializationOptions
                                                          (:cargo (:buildScripts (:enable t))
                                                                  :procMacro (:enable t))))
          ((python-mode python-ts-mode)                . ("pyright-langserver" "--stdio"))

          ))

  ;; Disable lsp auto-formatting
  (setq eglot-ignored-server-capabilities '(:documentOnTypeFormattingProvider))
  )

;; Auto-enable eglot
(dolist (hook '(c-mode-hook c-ts-mode-hook c++-mode-hook c++-ts-mode-hook
                            dts-mode-hook
                            rust-mode-hook rust-ts-mode-hook
                            python-mode-hook python-ts-mode-hook
                    ))
  (add-hook hook 'eglot-ensure))

Running in Qemu

1
2
3
4
5
6
7
8
9
10
qemu-system-aarch64 \
  -cpu cortex-a57 \
  -m 512M \
  -machine type=virt \
  -nographic \
  -smp 2 \
  -kernel ~/tftp/Image  \
  -initrd ~/tftp/initramfs.cpio.gz   \
  -append "rdinit=/linuxrc console=ttyAMA0" \
  -device virtio-scsi-device

Boot log:

1
2
3
4
5
6
7
8
[    0.000000] Booting Linux on physical CPU 0x0000000000 [0x411fd070]
[    0.000000] Linux version 5.10.238 ...
...
Please press Enter to activate this console.
~ #
~ # ls
bin      etc      lib      mnt      root     sys      usr
dev      home     linuxrc  proc     sbin     tmp      var

Press command + a, then x to exit Qemu.