Re: [PATCH bpf-next v2 2/2] bpf,riscv: Implement bpf_addr_space_cast instruction

[Puranjay Mohan]

On Mon, Mar 25, 2024 at 8:10 PM Conor Dooley <conor@xxxxxxxxxx> wrote:
>
> On Mon, Mar 25, 2024 at 03:54:34PM +0000, Puranjay Mohan wrote:
> > LLVM generates bpf_addr_space_cast instruction while translating
> > pointers between native (zero) address space and
> > __attribute__((address_space(N))). The addr_space=0 is reserved as
> > bpf_arena address space.
> >
> > rY = addr_space_cast(rX, 0, 1) is processed by the verifier and
> > converted to normal 32-bit move: wX = wY
> >
> > rY = addr_space_cast(rX, 1, 0) has to be converted by JIT.
> >
> > Signed-off-by: Puranjay Mohan <puranjay12@xxxxxxxxx>
>
> Doesn't compile for allmodconfig:
>   ../arch/riscv/net/bpf_jit_comp64.c:1086:7: error: call to undeclared function 'insn_is_cast_user'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>
> Cheers,
> Conor.

Yes,
I mentioned in the cover letter that a patch is required.
It just got merged in bpf-next/master:
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=770546ae9f4c1ae1ebcaf0874f0dd9631d77ec97

So, rebasing on the latest bpf-next/master should fix the issue.

Thanks,
Puranjay