[PATCH v2 2/2] powerpc/bpf: enable kfunc call

[Naveen N Rao]

On Tue, Feb 13, 2024 at 07:54:27AM +0000, Christophe Leroy wrote:
> 
> 
> Le 01/02/2024 à 18:12, Hari Bathini a écrit :
> > With module addresses supported, override bpf_jit_supports_kfunc_call()
> > to enable kfunc support. Module address offsets can be more than 32-bit
> > long, so override bpf_jit_supports_far_kfunc_call() to enable 64-bit
> > pointers.
> 
> What's the impact on PPC32 ? There are no 64-bit pointers on PPC32.

Looking at commit 1cf3bfc60f98 ("bpf: Support 64-bit pointers to 
kfuncs"), which added bpf_jit_supports_far_kfunc_call(), that does look 
to be very specific to platforms where module addresses are farther than 
s32. This is true for powerpc 64-bit, but shouldn't be needed for 
32-bit.

> 
> > 
> > Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
> > ---
> > 
> > * No changes since v1.
> > 
> > 
> >   arch/powerpc/net/bpf_jit_comp.c | 10 ++++++++++
> >   1 file changed, 10 insertions(+)
> > 
> > diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
> > index 7b4103b4c929..f896a4213696 100644
> > --- a/arch/powerpc/net/bpf_jit_comp.c
> > +++ b/arch/powerpc/net/bpf_jit_comp.c
> > @@ -359,3 +359,13 @@ void bpf_jit_free(struct bpf_prog *fp)
> >   
> >   	bpf_prog_unlock_free(fp);
> >   }
> > +
> > +bool bpf_jit_supports_kfunc_call(void)
> > +{
> > +	return true;
> > +}
> > +
> > +bool bpf_jit_supports_far_kfunc_call(void)
> > +{
> > +	return true;
> > +}

I am not sure there is value in keeping this as a separate patch since 
all support code for kfunc calls is introduced in an earlier patch.  
Consider folding this into the previous patch.

- Naveen