From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C5BD727473; Tue, 17 Sep 2024 04:40:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726548015; cv=none; b=sYmkEjoxaCbCn5B8hTp3SfMbtWSSQRpS2DXXS/4GY78G6evOMJMVyQMaTHo9zFsmrTg+x2bUpycAbw+xNJqUFlvF3IQyNnWC32B8rRXpQjwaZ39UJmosNPSrkzeXuXddkEwNpi/f+W89Ng1JCSSxv6R8JicCRdoyXGgT1Y6M3iw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726548015; c=relaxed/simple; bh=CG9TYl6xocSzcYJJoi1xTaKGt4Fy2IBNRupoEwgeoTw=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=OJrJhIxoEPB3FN1mCY8IgIvN89xKXpxxVedny9zKbha0LOrdi//XSAlmj+jfhBxcYSyMVEIp8Sj2yAlimDhkO8oowHskz1L091mSYV4V7O9maZCJAQkQOI1EWYbLKx8NDxEjPdCJppET+2tTV9q3nYe4kEfEjAMz8qa4yBMvHc8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=QinRfGhV; arc=none smtp.client-ip=209.85.214.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QinRfGhV" Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-2053525bd90so35047065ad.0; Mon, 16 Sep 2024 21:40:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1726548013; x=1727152813; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=6Xi3Le89ZCorv8WOuDMesnSd+PNRXsJ+vYBCnGClhdg=; b=QinRfGhVkad4kzXEjDn/jGAm/hPgU/PMfsnKQ/uTQu2FlJCkGAawKWWYu98YeJ5VR2 27jZ0YxGYvGzWGWbR7m1bSsSzmrlWa9xxhey5ZTpPM1iMc/6GpXsARNrsMLaFgt44SpE F8iKQs6jAC+PsR44g+hFC5BZ3fKEcgCbq/rfn1wQin7i3UwKIOFvTWqWwtLBRc7QpOOO Yh57MhU5iw7HZHsE8MAOt+UPZ5OGsEX5OblJJc44/cwXpv0wyPow8qUg7I/w12v0VJpS JklWEM4bli1o2XzjXoujP5yWBE53NwuSojkKNmF//ik/ezhdgXpCnwp2mq+pZzoFfXSB u6Qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726548013; x=1727152813; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=6Xi3Le89ZCorv8WOuDMesnSd+PNRXsJ+vYBCnGClhdg=; b=ugMxi2OlQvfn2b7iwsDiAT1jFU6XCNXtouuKN2pZtIIkFP3uT8+qiKLzzdVqrzkbnP MdxifvDRbF5dVreSiwNauLdeTmvLqgHMWmNfc3lN5KgAU6Cx5m7Ct8Ng+y+JRNrBM6An moD72A9r06eGZa0aNwKqKucZLwruF+LLgJUOlDu0EnE3vw34GuhmdFjtnqwB1wZysbhC 3Jkp2vE/21shiXPwJTocCntJVRwuoo7mGeekPy7qDEB7MsFZLzycZFr/YsLUXOKUYlQW nlN5d+t57aMfHI3OcWJa0iOQjnv02OgkhihJrliUd9KQ7a/5mWF2gviBxnQRnfnbEAAr WTsA== X-Forwarded-Encrypted: i=1; AJvYcCUGKVicsbqLkOagqPnSxORcEl8RMS3fOEnfJWMeb+b5zYmjCq1YALjShxnm0zM2MjY4SVtA90P5@vger.kernel.org X-Gm-Message-State: AOJu0Yy3tvbvzoKZGosZ6Ho7WRIWiAdQY+uvwC+jvP1tOuln1cUmoy26 AOqTyJhVHYpToeKMTn+VBh7STawacB+pqHoeR8+yT+ka0YdPFFtg X-Google-Smtp-Source: AGHT+IGqdeLeQsB5OnpU8yF2oIlfkjGO+qPJU2oc1cqdrn52ml71uSDVcw5XqBQ1cJdRp6ww5Nf6GA== X-Received: by 2002:a17:903:41c9:b0:206:b915:58e with SMTP id d9443c01a7336-20781d6197emr212058305ad.22.1726548012769; Mon, 16 Sep 2024 21:40:12 -0700 (PDT) Received: from [192.168.0.235] ([38.34.87.7]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-207946d4eadsm43355235ad.124.2024.09.16.21.40.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Sep 2024 21:40:12 -0700 (PDT) Message-ID: Subject: Re: [PATCH dwarves v1] pahole: generate "bpf_fastcall" decl tags for eligible kfuncs From: Eduard Zingerman To: Alan Maguire , dwarves@vger.kernel.org, arnaldo.melo@gmail.com Cc: bpf@vger.kernel.org, kernel-team@fb.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, yonghong.song@linux.dev, martin.lau@linux.dev Date: Mon, 16 Sep 2024 21:40:07 -0700 In-Reply-To: References: <20240916091921.2929615-1-eddyz87@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.4 (3.52.4-1.fc40) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2024-09-16 at 11:16 +0100, Alan Maguire wrote: [...] > hi Eduard, >=20 > you've added support for multiple declaration tags as part of this, but > I wonder if we could go slightly further to simplify any additional > future KF_* flags -> decl tag needs? >=20 > Specifically if we had an array of mappings such > that we can add support for new declaration tags by simply adding a new > flag and declaration tag string. When checking flags value in > btf_encoder__tag_kfunc(), we'd just walk the array entries, and for each > matching flag add the associated decl tag. Would that work? Hi Alan, That would be something like below. It works, but looks a bit over-complicated for my taste, wdyt? --- 8< ---------------------------------------- iff --git a/btf_encoder.c b/btf_encoder.c index ae059e0..b6178c3 100644 --- a/btf_encoder.c +++ b/btf_encoder.c @@ -39,7 +39,6 @@ #define BTF_ID_SET8_PFX "__BTF_ID__set8__" #define BTF_SET8_KFUNCS (1 << 0) #define BTF_KFUNC_TYPE_TAG "bpf_kfunc" -#define BTF_FASTCALL_TAG "bpf_fastcall" #define KF_FASTCALL (1 << 12) =20 struct btf_id_and_flag { @@ -1534,6 +1533,15 @@ static int add_kfunc_decl_tag(struct btf *btf, const= char *tag, __u32 id, const return 0; } =20 +enum kf_bit_nums { + KF_BIT_NUM_FASTCALL =3D 12, + KF_BIT_NUM_FASTCALL_NR +}; + +static const char *kfunc_tags[KF_BIT_NUM_FASTCALL_NR] =3D { + [KF_BIT_NUM_FASTCALL] =3D "bpf_fastcall" +}; + static int btf_encoder__tag_kfunc(struct btf_encoder *encoder, struct gobu= ffer *funcs, const char *kfunc, __u32 flags) { struct btf_func key =3D { .name =3D kfunc }; @@ -1559,8 +1567,11 @@ static int btf_encoder__tag_kfunc(struct btf_encoder= *encoder, struct gobuffer * err =3D add_kfunc_decl_tag(btf, BTF_KFUNC_TYPE_TAG, target->type_id= , kfunc); if (err < 0) return err; - if (flags & KF_FASTCALL) { - err =3D add_kfunc_decl_tag(btf, BTF_FASTCALL_TAG, target->t= ype_id, kfunc); + + for (uint32_t i =3D 0; i < KF_BIT_NUM_FASTCALL_NR; i++) { + if (!(flags & (1u << i)) || !kfunc_tags[i]) + continue; + err =3D add_kfunc_decl_tag(btf, kfunc_tags[i], target->type= _id, kfunc); if (err < 0) return err; } ---------------------------------------- >8 --- >=20 > > --- > > btf_encoder.c | 59 +++++++++++++++++++++++++++++++++++++-------------- > > 1 file changed, 43 insertions(+), 16 deletions(-) > >=20 > > diff --git a/btf_encoder.c b/btf_encoder.c > > index 8a2d92e..ae059e0 100644 > > --- a/btf_encoder.c > > +++ b/btf_encoder.c > > @@ -39,15 +39,19 @@ > > #define BTF_ID_SET8_PFX "__BTF_ID__set8__" > > #define BTF_SET8_KFUNCS (1 << 0) > > #define BTF_KFUNC_TYPE_TAG "bpf_kfunc" > > +#define BTF_FASTCALL_TAG "bpf_fastcall" > > +#define KF_FASTCALL (1 << 12) > > + >=20 > probably need an #ifndef KF_FASTCALL/#endif here once this makes it into > uapi. kfunc flags are defined in include/linux/btf.h so these should not be visible in the uapi/linux/btf.h, unless I'm confused. >=20 >=20 > > +struct btf_id_and_flag { > > + uint32_t id; > > + uint32_t flags; > > +}; [...]