How to cross-compile programs from amd64 to arm64

[bartsmykla]

I'm trying to cross-compile some of the programs built on top of libbpf-bootstrap, but I'm lacking expertise with C/C++ ecosystem. I see that support for cross-compilation was added in 7b60b4f
I would appreciate help with:

• what are the packages I have to have installed on Ubuntu 22.04 (amd64) to cross-compile programs to arm64?
• do I have to cross-compile libelf and zlib first? If so, any hints how can I do it?

My current results:

~ CROSS_COMPILE=aarch64-linux-gnu-g make all
  BINARY   bind
/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: cannot find -lelf: No such file or directory
/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: cannot find -lz: No such file or directory

[anakryiko]

@wangjie could you please help? I'm not very familiar with cross-compilation, unfortunately.

[setNull]

I'm trying to cross-compile some of the programs built on top of libbpf-bootstrap, but I'm lacking expertise with C/C++ ecosystem. I see that support for cross-compilation was added in 7b60b4f I would appreciate help with:

• what are the packages I have to have installed on Ubuntu 22.04 (amd64) to cross-compile programs to arm64?
• do I have to cross-compile libelf and zlib first? If so, any hints how can I do it?

My current results:

~ CROSS_COMPILE=aarch64-linux-gnu-g make all
  BINARY   bind
/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: cannot find -lelf: No such file or directory
/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: cannot find -lz: No such file or directory

Hi bartsmykla,
Yes, libbpf depends on libelf and libz, so you need declare where the libraries and header files can be found.
such as, make EXTRA_CFLAGS="-IXXX" EXTRA_LDFLAGS="-LXXX" ARCH=arm64.
You can get a copy of these libraries from here for quickly verification if you don't want to cross-compile them yourself.

[JiaHuann]

the same here，thanks

[JiaHuann]

libbpf-bootstrap-android
x86 -> android aarch64.
I embbed deps and add externel path to involve BTF file for android kernel，wish this can help you.

[anakryiko]

can you submit a clear PR with only necessary changes?

[JiaHuann]

can you submit a clear PR with only necessary changes?

Ok，I will do it recently.