From patchwork Sun Feb 4 21:06:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Xu X-Patchwork-Id: 13544794 X-Patchwork-Delegate: bpf@iogearbox.net Received: from wout2-smtp.messagingengine.com (wout2-smtp.messagingengine.com [64.147.123.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D27D532C9C; Sun, 4 Feb 2024 21:06:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=64.147.123.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707080821; cv=none; b=R7crLjqtx/396ByLciCf9D0Iu3D4np3LlRTD7VRbXqWpU6mZB1wllRy6c2seQ6n2zyGsD7JpnLObHo4aY3jnAHgetW0tI7nAfFe4Rsp0G8nkRjtz1lZbhfc5N9lxJe6ZZY49lbHw74WSdlgbsOaMMmI7BIgDN3Nzh1WW68rE7OA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707080821; c=relaxed/simple; bh=YAsD/PAFWTIjhY4PrFZj7zLRMfr6sUXw/riMUTifiN4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VFJ2vHGZgmtqYBfV8Bfaq6bZeFjNZsGowdHUWxh/JyixAnwfUTTFc9l8pDYK/CnVhxMb7wYJiG46YQN5QnoSsYBLuYRz/UOP31xIa6eMOe2SoC7Bh5UBS7t+q6MYNrHc9BBJIkOwjG83nVWe/73hPnbcuqVN8NamoV1tHSwEXxg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dxuuu.xyz; spf=pass smtp.mailfrom=dxuuu.xyz; dkim=pass (2048-bit key) header.d=dxuuu.xyz header.i=@dxuuu.xyz header.b=gtQxJm4k; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=vJZe1EsH; arc=none smtp.client-ip=64.147.123.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dxuuu.xyz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=dxuuu.xyz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=dxuuu.xyz header.i=@dxuuu.xyz header.b="gtQxJm4k"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="vJZe1EsH" Received: from compute7.internal (compute7.nyi.internal [10.202.2.48]) by mailout.west.internal (Postfix) with ESMTP id 3A5423200A0A; Sun, 4 Feb 2024 16:06:56 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute7.internal (MEProxy); Sun, 04 Feb 2024 16:06:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dxuuu.xyz; h=cc :cc:content-transfer-encoding:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:subject:subject:to:to; s=fm2; t=1707080815; x= 1707167215; bh=EFrOfStAu11VQIYVVSfiFO1xvDu+gV2R6+8jhfL5s5o=; b=g tQxJm4k0Sj763PETXN1Uzl2sXs2LMt+C+Vr98PxiG8kb4V6crVeuT0VD2tJC4GBk 4aMdpZCArNVmFAHLOkoLMFCpexMdu7Z+5lCKhgfof1N9gLUNURVxXDerMxtMg4Tj tDwQ6iF++PEu6fEq9BsgKhrGn2h5HE9AmonRp42Wvtcfw7kiagSGP3iA+uIabYzt dKkEm3Ge7FA3IsHyhCvSwiJmaWasoFed3f9slCAy14GnONlolJxwz+wQjpEie0+J RLq7e4OS6RUg+D7Pyqysrw39wGyeTKVEBx5IcbPPNL+6p7QtON++uqKuZ1HM5gZ/ aEj4CMFnoMa+F+uhjSGYQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:date:date:feedback-id:feedback-id:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm3; t=1707080815; x= 1707167215; bh=EFrOfStAu11VQIYVVSfiFO1xvDu+gV2R6+8jhfL5s5o=; b=v JZe1EsHKEPtaQ+cteY2V62aWGtSKOYBPH3vVtv93WFUt3z6RfxmkTz7Asv8pKy+3 LBVZA2uRhZnzSH0xrTLWeL4GlT+RgKj0TIDHQcaPxIntAeBBJYllBXUixL2IrbfT Z2IJSf4sgyOf8CyJc3FM5Vb2GDJGpSoNgqQira/JSm4JL665ULVi4rVq8/bK23f+ /PjDNwl19q8uTn6adHjJj2jdG82xP/AsIZGBUJy8pgUhYgMv/iiNJdAFmnLcKZCa 4NH7RksWyE3NFs9Katt4gSmZxhp1AjzVfELJ28AlPO//NasIbfoeWhXPWYmHxu9p sLXeJ0ZqKiopGr9MQIsUA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvkedrfedukedgudeggecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecufghrlhcuvffnffculdefhedmnecujfgurhephf fvvefufffkofgjfhgggfestdekredtredttdenucfhrhhomhepffgrnhhivghlucgiuhcu oegugihusegugihuuhhurdighiiiqeenucggtffrrghtthgvrhhnpeelieduhefhteffie dutdejgfdutdekudelueelveekjeeitdefueeutdelhedvfeenucffohhmrghinhepkhgv rhhnvghlrdhorhhgnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilh hfrhhomhepugiguhesugiguhhuuhdrgiihii X-ME-Proxy: Feedback-ID: i6a694271:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 4 Feb 2024 16:06:53 -0500 (EST) From: Daniel Xu To: quentin@isovalent.com, daniel@iogearbox.net, ast@kernel.org, andrii@kernel.org, olsajiri@gmail.com, alan.maguire@oracle.com Cc: martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v2 2/2] bpftool: Support dumping kfunc prototypes from BTF Date: Sun, 4 Feb 2024 14:06:35 -0700 Message-ID: <9b8ebd13300e28bd92a2e6de4fb04f85c1b6ce7c.1707080349.git.dxu@dxuuu.xyz> X-Mailer: git-send-email 2.42.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net This patch enables dumping kfunc prototypes from bpftool. This is useful b/c with this patch, end users will no longer have to manually define kfunc prototypes. For the kernel tree, this also means we can drop kfunc prototypes from: tools/testing/selftests/bpf/bpf_kfuncs.h tools/testing/selftests/bpf/bpf_experimental.h Example usage: $ make PAHOLE=/home/dxu/dev/pahole/build/pahole -j30 vmlinux $ ./tools/bpf/bpftool/bpftool btf dump file ./vmlinux format c | rg "__ksym;" | head -3 extern void cgroup_rstat_updated(struct cgroup *cgrp, int cpu) __weak __ksym; extern void cgroup_rstat_flush(struct cgroup *cgrp) __weak __ksym; extern struct bpf_key *bpf_lookup_user_key(u32 serial, u64 flags) __weak __ksym; Note that this patch is only effective after the enabling pahole [0] change is merged and the resulting feature enabled with --btf_features=decl_tag_kfuncs. [0]: https://lore.kernel.org/bpf/cover.1707071969.git.dxu@dxuuu.xyz/ Signed-off-by: Daniel Xu --- tools/bpf/bpftool/btf.c | 45 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 91fcb75babe3..0fd78a476286 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -20,6 +20,8 @@ #include "json_writer.h" #include "main.h" +#define KFUNC_DECL_TAG "bpf_kfunc" + static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_UNKN] = "UNKNOWN", [BTF_KIND_INT] = "INT", @@ -454,6 +456,39 @@ static int dump_btf_raw(const struct btf *btf, return 0; } +static int dump_btf_kfuncs(struct btf_dump *d, const struct btf *btf) +{ + DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts); + int cnt = btf__type_cnt(btf); + int i; + + for (i = 1; i < cnt; i++) { + const struct btf_type *t = btf__type_by_id(btf, i); + const struct btf_type *kft; + const char *name; + int err; + + if (!btf_is_decl_tag(t)) + continue; + + name = btf__name_by_offset(btf, t->name_off); + if (strncmp(name, KFUNC_DECL_TAG, sizeof(KFUNC_DECL_TAG))) + continue; + + printf("extern "); + + kft = btf__type_by_id(btf, t->type); + opts.field_name = btf__name_by_offset(btf, kft->name_off); + err = btf_dump__emit_type_decl(d, kft->type, &opts); + if (err) + return err; + + printf(" __weak __ksym;\n\n"); + } + + return 0; +} + static void __printf(2, 0) btf_dump_printf(void *ctx, const char *fmt, va_list args) { @@ -476,6 +511,12 @@ static int dump_btf_c(const struct btf *btf, printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n"); printf("#endif\n\n"); + printf("#ifndef __ksym\n"); + printf("#define __ksym __attribute__((section(\".ksyms\")))\n"); + printf("#endif\n\n"); + printf("#ifndef __weak\n"); + printf("#define __weak __attribute__((weak))\n"); + printf("#endif\n\n"); if (root_type_cnt) { for (i = 0; i < root_type_cnt; i++) { @@ -491,6 +532,10 @@ static int dump_btf_c(const struct btf *btf, if (err) goto done; } + + err = dump_btf_kfuncs(d, btf); + if (err) + goto done; } printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");