Re: Perf not able to cross compile

[Arnaldo Carvalho de Melo]

Em Thu, Feb 01, 2024 at 11:52:07AM +0000, James Clark escreveu:
> 
> 
> On 01/02/2024 11:32, Anders Roxell wrote:
> > Hey,
> > 
> > I'm trying to cross compile perf ARCH=arm64 on my x86_64 host from
> > linus tree [1], branch master.
> > 
> > 
> > This is the failue I see, full log [2]:
> > 
> > ...
> >   CC      /home/tuxbuild/.cache/tuxmake/builds/1/build/libbpf/staticobjs/elf.o
> >   CC      /home/tuxbuild/.cache/tuxmake/builds/1/build/libbpf/staticobjs/features.o
> > cc1: error: ‘-fcf-protection=full’ is not supported for this target
> > error: command '/usr/local/bin/sccache' failed with exit code 1
> > cp: cannot stat
> > '/home/tuxbuild/.cache/tuxmake/builds/1/build/python_ext_build/lib/perf*.so':
> > No such file or directory
> > make[2]: *** [Makefile.perf:678:
> > /home/tuxbuild/.cache/tuxmake/builds/1/build/python/perf.cpython-311-x86_64-linux-gnu.so]
> > Error 1
> > make[2]: *** Waiting for unfinished jobs....
> >   LD      /home/tuxbuild/.cache/tuxmake/builds/1/build/libbpf/staticobjs/libbpf-in.o
> >   LINK    /home/tuxbuild/.cache/tuxmake/builds/1/build/libbpf/libbpf.a
> > make[1]: *** [Makefile.perf:261: sub-make] Error 2
> > make: *** [Makefile:70: all] Error 2
> > 
> > Running 'x86_64-linux-gnu-python3-config --cflags' I see
> > '-fcf-protection' in the output and this happens when I'm building
> > cross compile arm64 on my x86_64 host machine. Building on an arm64
> > host works. cross compile x86_64 on my x86_64 host works too.
> > 
> > I have 'aarch64-linux-gnu-python3-config' installed but that isn't used.
> > 
> > $ x86_64-linux-gnu-python3-config --cflags
> > -I/usr/include/python3.11 -I/usr/include/python3.11  -Wsign-compare -g
> >   -fstack-protector-strong -fstack-clash-protection -Wformat
> > -Werror=format-security -fcf-protection  -DNDEBUG -g -fwrapv -O2 -Wall
> > $ aarch64-linux-gnu-python3-config --cflags
> > -I/usr/include/python3.11 -I/usr/include/python3.11  -Wsign-compare -g
> >   -fstack-protector-strong -fstack-clash-protection -Wformat
> > -Werror=format-security -mbranch-protection=standard  -DNDEBUG -g
> > -fwrapv -O2 -Wall
> > 
> > I tried to set PYTHON and PYTHON_CONFIG too, but didn't work.
> > 
> > It doesn't try to use $(CROSS_COMPILE)python3-config, any idea how to
> > use the correct config?
> > 
> > Cheers,
> > Anders
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > [2]  https://storage.tuxsuite.com/public/linaro/lkft/builds/2bc6x6cISHzG9Jgo0oAVv2OgLOG/build.log
> 
> 
> Hi Anders,
> 
> I see something similar but in the end it works. Despite the name, I
> also get perf.cpython-311-x86_64-linux-gnu.so generated in my build, but
> it's actually an arm binary.
> 
> For me I'm using python3.10, and the x86 config options don't include
> -fcf-protection which is probably why it can compile successfully with
> the arm compiler.
> 
> It looks like your assumption is correct and it's not using
> $(CROSS_COMPILE)python3-config but just python3-config. The answer to
> how to fix it is probably to start hacking at the makefiles, if PYTHON
> and PYTHON_CONFIG don't work either.

Right, that seems like a good direction in trying to fix this.

- Arnaldo