From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf@vger.kernel.org, "Alexei Starovoitov" <ast@kernel.org>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Pablo Neira Ayuso" <pablo@netfilter.org>,
"Florian Westphal" <fw@strlen.de>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Lorenzo Bianconi" <lorenzo@kernel.org>,
netdev@vger.kernel.org, netfilter-devel@vger.kernel.org
Subject: Re: [PATCH bpf-next v6 01/13] bpf: Introduce BTF ID flags and 8-byte BTF set
Date: Wed, 20 Jul 2022 20:42:54 +0200 [thread overview]
Message-ID: <CAP01T753gZgg2501YR9rhCTCiHAf-zUe3USPqptAV43RWzJCVg@mail.gmail.com> (raw)
In-Reply-To: <20220719183745.4ojhwpuo7ookjvvk@MacBook-Pro-3.local>
On Tue, 19 Jul 2022 at 20:37, Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Tue, Jul 19, 2022 at 03:24:18PM +0200, Kumar Kartikeya Dwivedi wrote:
> >
> > +#define ____BTF_ID_FLAGS_LIST(_0, _1, _2, _3, _4, _5, N, ...) _1##_##_2##_##_3##_##_4##_##_5##__
> > +#define __BTF_ID_FLAGS_LIST(...) ____BTF_ID_FLAGS_LIST(0x0, ##__VA_ARGS__, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
> > +
> > +#define __FLAGS(prefix, ...) \
> > + __PASTE(prefix, __BTF_ID_FLAGS_LIST(__VA_ARGS__))
> > +
> > +#define BTF_ID_FLAGS(prefix, name, ...) \
> > + BTF_ID(prefix, name) \
> > + __BTF_ID(__ID(__FLAGS(__BTF_ID__flags__, ##__VA_ARGS__)))
> > +
> > /*
> > * The BTF_ID_LIST macro defines pure (unsorted) list
> > * of BTF IDs, with following layout:
> > @@ -145,10 +164,53 @@ asm( \
> > ".popsection; \n"); \
> > extern struct btf_id_set name;
> >
> > +/*
> > + * The BTF_SET8_START/END macros pair defines sorted list of
> > + * BTF IDs and their flags plus its members count, with the
> > + * following layout:
> > + *
> > + * BTF_SET8_START(list)
> > + * BTF_ID_FLAGS(type1, name1, flags...)
> > + * BTF_ID_FLAGS(type2, name2, flags...)
> > + * BTF_SET8_END(list)
> > + *
> > + * __BTF_ID__set8__list:
> > + * .zero 8
> > + * list:
> > + * __BTF_ID__type1__name1__3:
> > + * .zero 4
> > + * __BTF_ID__flags__0x0_0x0_0x0_0x0_0x0__4:
> > + * .zero 4
>
> Overall looks great,
> but why encode flags into a name?
> Why reuse ____BTF_ID for flags and complicate resolve_btfid?
> Instead of .zero 4 insert the actual flags as .word ?
>
> The usage will be slightly different.
> Instead of:
> BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE, KF_RET_NULL)
> it will be
> BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE | KF_RET_NULL)
Nice, I didn't know you could do complex expressions like this for asm
directives like .word, but it makes sense now. TIL. I'm not very well
versed with GNU as. I will rework this and drop the resolve_btfids
changes for flags. Thanks a lot!
next prev parent reply other threads:[~2022-07-20 18:43 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 13:24 [PATCH bpf-next v6 00/13] New nf_conntrack kfuncs for insertion, changing timeout, status Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 01/13] bpf: Introduce BTF ID flags and 8-byte BTF set Kumar Kartikeya Dwivedi
2022-07-19 18:37 ` Alexei Starovoitov
2022-07-20 18:42 ` Kumar Kartikeya Dwivedi [this message]
2022-07-19 13:24 ` [PATCH bpf-next v6 02/13] tools/resolve_btfids: Add support for resolving kfunc flags Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 03/13] bpf: Switch to new kfunc flags infrastructure Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 04/13] bpf: Add support for forcing kfunc args to be trusted Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 05/13] bpf: Add documentation for kfuncs Kumar Kartikeya Dwivedi
2022-07-20 17:03 ` Toke Høiland-Jørgensen
2022-07-20 18:45 ` Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 06/13] net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 07/13] net: netfilter: Add kfuncs to allocate and insert CT Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 08/13] net: netfilter: Add kfuncs to set and change CT timeout Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 09/13] net: netfilter: Add kfuncs to set and change CT status Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 10/13] selftests/bpf: Add verifier tests for trusted kfunc args Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 11/13] selftests/bpf: Add tests for new nf_conntrack kfuncs Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 12/13] selftests/bpf: Add negative " Kumar Kartikeya Dwivedi
2022-07-19 13:24 ` [PATCH bpf-next v6 13/13] selftests/bpf: Fix test_verifier failed test in unprivileged mode Kumar Kartikeya Dwivedi
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