From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70ECCC433F5 for ; Tue, 10 May 2022 07:47:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233367AbiEJHvS (ORCPT ); Tue, 10 May 2022 03:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234014AbiEJHvQ (ORCPT ); Tue, 10 May 2022 03:51:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 087A518C582; Tue, 10 May 2022 00:47:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7E24660C11; Tue, 10 May 2022 07:47:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40E14C385C9; Tue, 10 May 2022 07:47:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652168838; bh=G2fb7PblCjCawCg9BEx1U6t/qNzr4r9GSumb8avo1wQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gvDxfQJoZ1ErEEIJTvzZ1dSFKhxZL4Qc07p3bvZvhYKmKcEoNyi505Mt2HiCO6cyv Qdcvr/mrQGlA1EnDEt7pTLqs7jYKLtEf+HQ6ygcKCLGzHB654u1gSlMOcg4BZbPh+z kOCNADdO+4XWxP4YYTbVXqTuh6DWXnOd80jO6sHMi+JVdB1QxuQDNm1oaalL5K1xHa qZM3oRjboaNarPxT0L5fxG56WJjG/hxu3wDB5GjTYlGyV9PKZvRpSzxqgeQGJHRz78 iI1m3r+VfQBYq0WLnOCfcDwI0itnAjwoYgpQBwmXPLyfXbfx/6OtGOkJlxcySyhnVi VyBO8Bh8BE47w== From: Jiri Olsa To: Arnaldo Carvalho de Melo , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: linux-perf-users@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Ingo Molnar , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , Ian Rogers Subject: [PATCHv2 bpf-next 1/3] libbpf: Add bpf_program__set_insns function Date: Tue, 10 May 2022 09:46:57 +0200 Message-Id: <20220510074659.2557731-2-jolsa@kernel.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220510074659.2557731-1-jolsa@kernel.org> References: <20220510074659.2557731-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Adding bpf_program__set_insns that allows to set new instructions for program. This is a very advanced libbpf API and users need to know what they are doing. This should be used from prog_prepare_load_fn callback only. We can have changed instructions after calling prog_prepare_load_fn callback, reloading them. Signed-off-by: Jiri Olsa --- tools/lib/bpf/libbpf.c | 22 ++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 18 ++++++++++++++++++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 41 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 15117b9a4d1e..7c17ab9f99ca 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6862,6 +6862,8 @@ static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_prog prog->name, err); return err; } + insns = prog->insns; + insns_cnt = prog->insns_cnt; } if (obj->gen_loader) { @@ -8790,6 +8792,26 @@ size_t bpf_program__insn_cnt(const struct bpf_program *prog) return prog->insns_cnt; } +int bpf_program__set_insns(struct bpf_program *prog, + struct bpf_insn *new_insns, size_t new_insn_cnt) +{ + struct bpf_insn *insns; + + if (prog->obj->loaded) + return -EBUSY; + + insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns)); + if (!insns) { + pr_warn("prog '%s': failed to realloc prog code\n", prog->name); + return -ENOMEM; + } + memcpy(insns, new_insns, new_insn_cnt * sizeof(*insns)); + + prog->insns = insns; + prog->insns_cnt = new_insn_cnt; + return 0; +} + int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, bpf_program_prep_t prep) { diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 114b1f6f73a5..5f94459db751 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -323,6 +323,24 @@ struct bpf_insn; * different. */ LIBBPF_API const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog); + +/** + * @brief **bpf_program__set_insns()** can set BPF program's underlying + * BPF instructions. + * + * WARNING: This is a very advanced libbpf API and users need to know + * what they are doing. This should be used from prog_prepare_load_fn + * callback only. + * + * @param prog BPF program for which to return instructions + * @param new_insns a pointer to an array of BPF instructions + * @param new_insn_cnt number of `struct bpf_insn`'s that form + * specified BPF program + * @return 0, on success; negative error code, otherwise + */ +LIBBPF_API int bpf_program__set_insns(struct bpf_program *prog, + struct bpf_insn *new_insns, size_t new_insn_cnt); + /** * @brief **bpf_program__insn_cnt()** returns number of `struct bpf_insn`'s * that form specified BPF program. diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index b5bc84039407..9eb14ce152dc 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -448,6 +448,7 @@ LIBBPF_0.8.0 { bpf_object__open_subskeleton; bpf_program__attach_kprobe_multi_opts; bpf_program__attach_usdt; + bpf_program__set_insns; libbpf_register_prog_handler; libbpf_unregister_prog_handler; } LIBBPF_0.7.0; -- 2.35.3