Re: [PATCH bpf-next 1/3] libbpf: add asm/unistd.h to xsk to get __NR_mmap2

[Ivan Khoronzhuk]

On Tue, Aug 13, 2019 at 04:38:13PM -0700, Andrii Nakryiko wrote:

Hi, Andrii

> On Tue, Aug 13, 2019 at 3:24 AM Ivan Khoronzhuk
> <ivan.khoronzhuk@xxxxxxxxxx> wrote:
> > That's needed to get __NR_mmap2 when mmap2 syscall is used.
> >
> > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
> > ---
> >  tools/lib/bpf/xsk.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
> > index 5007b5d4fd2c..f2fc40f9804c 100644
> > --- a/tools/lib/bpf/xsk.c
> > +++ b/tools/lib/bpf/xsk.c
> > @@ -12,6 +12,7 @@
> >  #include <stdlib.h>
> >  #include <string.h>
> >  #include <unistd.h>
> > +#include <asm/unistd.h>
>
> asm/unistd.h is not present in Github libbpf projection. Is there any

Look on includes from
tools/lib/bpf/libpf.c
tools/lib/bpf/bpf.c

That's how it's done... Copping headers to arch/arm will not
solve this, it includes both of them anyway, and anyway it needs
asm/unistd.h inclusion here, only because xsk.c needs __NR_*


> way to avoid including this header? Generally, libbpf can't easily use
> all of kernel headers, we need to re-implemented all the extra used
> stuff for Github version of libbpf, so we try to minimize usage of new
> headers that are not just plain uapi headers from include/uapi.

Yes I know, it's far away from real number of changes needed.
I faced enough about this already and kernel headers, especially
for arm32 it's a bit decency problem. But this patch it's part of
normal one. I have couple issues despite this normally fixed mmap2
that is the same even if uapi includes are coppied to tools/arch/arm.

In continuation of kernel headers inclusion and arm build:

For instance, what about this rough "kernel headers" hack:
https://github.com/ikhorn/af_xdp_stuff/commit/aa645ccca4d844f404ec3c2b27402d4d7848d1b5

or this one related for arm32 only:
https://github.com/ikhorn/af_xdp_stuff/commit/2c6c6d538605aac39600dcb3c9b66de11c70b963

I have more...

> >  #include <arpa/inet.h>
> >  #include <asm/barrier.h>
> >  #include <linux/compiler.h>
> > --
> > 2.17.1

--
Regards,
Ivan Khoronzhuk