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 CF6D8C433EF for ; Fri, 22 Apr 2022 10:01:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1446361AbiDVKEN (ORCPT ); Fri, 22 Apr 2022 06:04:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1446354AbiDVKEM (ORCPT ); Fri, 22 Apr 2022 06:04:12 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36EE253B7C; Fri, 22 Apr 2022 03:01:19 -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 C7C8961E25; Fri, 22 Apr 2022 10:01:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02857C385AA; Fri, 22 Apr 2022 10:01:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650621678; bh=SoXivtN+WDMyu86XjuSaxFCb9sQo39F8l+g0EQFcewY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lJolsis8aO6YR5ZczGJaUsva2pb/UDje6HqW1zQxTgfzGnnkXJ1BTW3HWhXhU7q/k KCng61TLm2CCRtbaPtKnn5oCKVmcNhr7y12IzJtjcbhADwRn+HktpQJ385f8yx6srf +KD65U4HVkut0pg+g2If5zeNFJJVXdRrHvlo6eAieAwZtyXKece+6M+ionkq+YF9fE 7T7eYZeEsAEV5YVGGu0ugEMJupWlgC8lJBhs4fz408f9kj18gQJZvIZ92ncW5Cf+2S JkwzBiIWRk71Cg0N6e8FxK8wnzmqNfxRZfW82aSh1EYYA7VzytDEL/A7cZ4C3+zi9e vSY/AMJrd1dkw== 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: [PATCH perf/core 4/5] perf tools: Register perfkprobe libbpf section handler Date: Fri, 22 Apr 2022 12:00:24 +0200 Message-Id: <20220422100025.1469207-5-jolsa@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220422100025.1469207-1-jolsa@kernel.org> References: <20220422100025.1469207-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org Perf is using section name to declare special kprobe arguments, which no longer works with current libbpf, that either requires certain form of the section name or allows to register custom handler. Adding support for 'perfkprobe/' section name handler to take care of perf kprobe programs. The handler servers two purposes: - allows perf programs to have special arguments in section name - allows perf to use pre-load callback where we can attach init code (zeroing all argument registers) to each perf program The second is essential part of new prologue generation code, that's coming in following patch. Signed-off-by: Jiri Olsa --- tools/perf/util/bpf-loader.c | 50 ++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index f8ad581ea247..92dd8cc18edb 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -86,6 +86,7 @@ bpf_perf_object__next(struct bpf_perf_object *prev) (perf_obj) = (tmp), (tmp) = bpf_perf_object__next(tmp)) static bool libbpf_initialized; +static int libbpf_sec_handler; static int bpf_perf_object__add(struct bpf_object *obj) { @@ -99,12 +100,61 @@ static int bpf_perf_object__add(struct bpf_object *obj) return perf_obj ? 0 : -ENOMEM; } +static struct bpf_insn prologue_init_insn[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_MOV64_IMM(BPF_REG_1, 0), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_MOV64_IMM(BPF_REG_4, 0), + BPF_MOV64_IMM(BPF_REG_5, 0), +}; + +#define LIBBPF_SEC_PREFIX "perfkprobe/" + +static int libbpf_prog_prepare_load_fn(struct bpf_program *prog, + struct bpf_prog_load_opts *opts __maybe_unused, + long cookie __maybe_unused) +{ + size_t init_size_cnt = ARRAY_SIZE(prologue_init_insn); + size_t orig_insn_cnt, insn_cnt, init_size, orig_size; + const struct bpf_insn *orig_insn; + struct bpf_insn *insn; + + /* prepend initialization code to program instructions */ + orig_insn = bpf_program__insns(prog); + orig_insn_cnt = bpf_program__insn_cnt(prog); + init_size = init_size_cnt * sizeof(*insn); + orig_size = orig_insn_cnt * sizeof(*insn); + + insn_cnt = orig_insn_cnt + init_size_cnt; + insn = malloc(insn_cnt * sizeof(*insn)); + if (!insn) + return -ENOMEM; + + memcpy(insn, prologue_init_insn, init_size); + memcpy((char *) insn + init_size, orig_insn, orig_size); + bpf_program__set_insns(prog, insn, insn_cnt); + return 0; +} + static int libbpf_init(void) { + LIBBPF_OPTS(libbpf_prog_handler_opts, handler_opts, + .prog_prepare_load_fn = libbpf_prog_prepare_load_fn, + ); + if (libbpf_initialized) return 0; libbpf_set_print(libbpf_perf_print); + libbpf_sec_handler = libbpf_register_prog_handler(LIBBPF_SEC_PREFIX, + BPF_PROG_TYPE_KPROBE, + 0, &handler_opts); + if (libbpf_sec_handler < 0) { + pr_debug("bpf: failed to register libbpf section handler: %d\n", + libbpf_sec_handler); + return -BPF_LOADER_ERRNO__INTERNAL; + } libbpf_initialized = true; return 0; } -- 2.35.1