From: John Fastabend <john.fastabend@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>, davem@davemloft.net
Cc: daniel@iogearbox.net, x86@kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, kernel-team@fb.com
Subject: RE: [PATCH bpf-next 02/10] bpf: add typecast to bpf helpers to help BTF generation
Date: Sat, 05 Oct 2019 21:00:32 -0700 [thread overview]
Message-ID: <5d9966e09618b_41932aacfa49e5b8cb@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20191005050314.1114330-3-ast@kernel.org>
Alexei Starovoitov wrote:
> When pahole converts dwarf to btf it emits only used types.
> Wrap existing bpf helper functions into typedef and use it in
> typecast to make gcc emits this type into dwarf.
> Then pahole will convert it to btf.
> The "btf_#name_of_helper" types will be used to figure out
> types of arguments of bpf helpers.
> The generate code before and after is the same.
> Only dwarf and btf are different.
>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> ---
> include/linux/filter.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index 2ce57645f3cd..d3d51d7aff2c 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -464,10 +464,11 @@ static inline bool insn_is_zext(const struct bpf_insn *insn)
> #define BPF_CALL_x(x, name, ...) \
> static __always_inline \
> u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \
> + typedef u64 (*btf_##name)(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \
> u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \
> u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)) \
> { \
> - return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
> + return ((btf_##name)____##name)(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
> } \
> static __always_inline \
> u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))
> --
> 2.20.0
>
Acked-by: John Fastabend <john.fastabend@gmail.com>
next prev parent reply other threads:[~2019-10-06 4:00 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-05 5:03 [PATCH bpf-next 00/10] bpf: revolutionize bpf tracing Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 01/10] bpf: add typecast to raw_tracepoints to help BTF generation Alexei Starovoitov
2019-10-05 18:40 ` Andrii Nakryiko
2019-10-06 3:58 ` John Fastabend
2019-10-05 5:03 ` [PATCH bpf-next 02/10] bpf: add typecast to bpf helpers " Alexei Starovoitov
2019-10-05 18:41 ` Andrii Nakryiko
2019-10-06 4:00 ` John Fastabend [this message]
2019-10-05 5:03 ` [PATCH bpf-next 03/10] bpf: process in-kernel BTF Alexei Starovoitov
2019-10-06 6:36 ` Andrii Nakryiko
2019-10-06 23:49 ` Alexei Starovoitov
2019-10-07 0:20 ` Andrii Nakryiko
2019-10-09 20:51 ` Martin Lau
2019-10-10 3:43 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 04/10] libbpf: auto-detect btf_id of raw_tracepoint Alexei Starovoitov
2019-10-07 23:41 ` Andrii Nakryiko
2019-10-09 2:26 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 05/10] bpf: implement accurate raw_tp context access via BTF Alexei Starovoitov
2019-10-07 16:32 ` Alan Maguire
2019-10-09 3:59 ` Alexei Starovoitov
2019-10-08 0:35 ` Andrii Nakryiko
2019-10-09 3:30 ` Alexei Starovoitov
2019-10-09 4:01 ` Andrii Nakryiko
2019-10-09 5:10 ` Andrii Nakryiko
2019-10-10 3:54 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 06/10] bpf: add support for BTF pointers to interpreter Alexei Starovoitov
2019-10-08 3:08 ` Andrii Nakryiko
2019-10-05 5:03 ` [PATCH bpf-next 07/10] bpf: add support for BTF pointers to x86 JIT Alexei Starovoitov
2019-10-05 6:03 ` Eric Dumazet
2019-10-09 17:38 ` Andrii Nakryiko
2019-10-09 17:46 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 08/10] bpf: check types of arguments passed into helpers Alexei Starovoitov
2019-10-09 18:01 ` Andrii Nakryiko
2019-10-09 19:58 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 09/10] bpf: disallow bpf_probe_read[_str] helpers Alexei Starovoitov
2019-10-09 5:29 ` Andrii Nakryiko
2019-10-09 19:38 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 10/10] selftests/bpf: add kfree_skb raw_tp test Alexei Starovoitov
2019-10-09 5:36 ` Andrii Nakryiko
2019-10-09 17:37 ` Alexei Starovoitov
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