Re: bpf: Request to add -mcpu=v4 support for ARM/MIPS/NFP/POWERPC/RISCV/S390/SPARC/X86_32

[Louis Peens <louis.peens@corigine.com>]

On Mon, Aug 21, 2023 at 12:47:11PM -0700, Jakub Kicinski wrote:
> On Sat, 19 Aug 2023 18:41:30 -0700 Yonghong Song wrote:
> > Hi,
> > 
> > A new set of bpf insns have been recently added in llvm with flag
> > [-mcpu=v4](https://reviews.llvm.org/D144829). In the kernel,
> > x86_64 and arm64 have implemented -mcpu=v4 support:
> >    x86_64: 
> > https://lore.kernel.org/all/20230728011143.3710005-1-yonghong.song@linux.dev/
> >    arm64: 
> > https://lore.kernel.org/bpf/20230815154158.717901-1-xukuohai@huaweicloud.com/
> > 
> > The following arch's do not have -mcpu=v4 support yet:
> >    arm, mips, nfp, powerpc, riscv, sc90, sparc and x86_32
> > 
> > If you have a chance, could you take a look at what
> > x86_64/arm64 does and add support to the above arch'es?
> 
> Louis, is anyone on your side still working on BPF for NFP?
> div/mod and the jump will be impossible but there may be instructions
> for sign extend or bswap?
There isn't a lot of activity on the BPF side for nfp, but here and
there some things do get addressed. I will run it past the team, it does
seem like those might be possible with the architecture - thanks for the
ping.