From patchwork Sat Oct 31 22:31:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 11871807 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC344C4741F for ; Sat, 31 Oct 2020 22:31:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6078E20791 for ; Sat, 31 Oct 2020 22:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604183507; bh=h81m6A0eBQpOpeNziJROeLT53Gkl9+MuCT0vOM4ACm4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nQZ8IAWPe/yC49s7HiBU5AC/EYtl5K1uaGE5RoWmoEiXd+W+fx5xOR5BSfPM0qiva 2HjOWZ8TY1jefXyztdb1xYvQyC93FG4Si9+stvEbJjYeWpmhZHE8Z5kW12dlQ73kit yjd00JEk2oPbUsU0LDB5Y3ybTjt3n1Z6pp4yke7s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726003AbgJaWbr convert rfc822-to-8bit (ORCPT ); Sat, 31 Oct 2020 18:31:47 -0400 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:30542 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725842AbgJaWbq (ORCPT ); Sat, 31 Oct 2020 18:31:46 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-216-1haZIE5wPSmyLyCvS_t6Lg-1; Sat, 31 Oct 2020 18:31:42 -0400 X-MC-Unique: 1haZIE5wPSmyLyCvS_t6Lg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0DA4B1084D62; Sat, 31 Oct 2020 22:31:41 +0000 (UTC) Received: from krava.redhat.com (unknown [10.40.192.83]) by smtp.corp.redhat.com (Postfix) with ESMTP id D137C6F142; Sat, 31 Oct 2020 22:31:38 +0000 (UTC) From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: dwarves@vger.kernel.org, bpf@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , Yonghong Song , Hao Luo , "Frank Ch. Eigler" , Mark Wielaard Subject: [PATCH 1/2] btf_encoder: Move find_all_percpu_vars in generic collect_symbols Date: Sat, 31 Oct 2020 23:31:30 +0100 Message-Id: <20201031223131.3398153-2-jolsa@kernel.org> In-Reply-To: <20201031223131.3398153-1-jolsa@kernel.org> References: <20201031223131.3398153-1-jolsa@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jolsa@kernel.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Moving find_all_percpu_vars under generic collect_symbols function that walks over symbols and calls collect_percpu_var. We will add another collect function that needs to go through all the symbols, so it's better we go through them just once. There's no functional change intended. Signed-off-by: Jiri Olsa Acked-by: Hao Luo --- btf_encoder.c | 124 +++++++++++++++++++++++++++----------------------- 1 file changed, 67 insertions(+), 57 deletions(-) diff --git a/btf_encoder.c b/btf_encoder.c index 4c92908beab2..1866bb16a8ba 100644 --- a/btf_encoder.c +++ b/btf_encoder.c @@ -250,75 +250,85 @@ static bool percpu_var_exists(uint64_t addr, uint32_t *sz, const char **name) return true; } -static int find_all_percpu_vars(struct btf_elf *btfe) +static int collect_percpu_var(struct btf_elf *btfe, GElf_Sym *sym) { - uint32_t core_id; - GElf_Sym sym; + const char *sym_name; + uint64_t addr; + uint32_t size; - /* cache variables' addresses, preparing for searching in symtab. */ - percpu_var_cnt = 0; + /* compare a symbol's shndx to determine if it's a percpu variable */ + if (elf_sym__section(sym) != btfe->percpu_shndx) + return 0; + if (elf_sym__type(sym) != STT_OBJECT) + return 0; - /* search within symtab for percpu variables */ - elf_symtab__for_each_symbol(btfe->symtab, core_id, sym) { - const char *sym_name; - uint64_t addr; - uint32_t size; + addr = elf_sym__value(sym); + /* + * Store only those symbols that have allocated space in the percpu section. + * This excludes the following three types of symbols: + * + * 1. __ADDRESSABLE(sym), which are forcely emitted as symbols. + * 2. __UNIQUE_ID(prefix), which are introduced to generate unique ids. + * 3. __exitcall(fn), functions which are labeled as exit calls. + * + * In addition, the variables defined using DEFINE_PERCPU_FIRST are + * also not included, which currently includes: + * + * 1. fixed_percpu_data + */ + if (!addr) + return 0; - /* compare a symbol's shndx to determine if it's a percpu variable */ - if (elf_sym__section(&sym) != btfe->percpu_shndx) - continue; - if (elf_sym__type(&sym) != STT_OBJECT) - continue; + size = elf_sym__size(sym); + if (!size) + return 0; /* ignore zero-sized symbols */ - addr = elf_sym__value(&sym); - /* - * Store only those symbols that have allocated space in the percpu section. - * This excludes the following three types of symbols: - * - * 1. __ADDRESSABLE(sym), which are forcely emitted as symbols. - * 2. __UNIQUE_ID(prefix), which are introduced to generate unique ids. - * 3. __exitcall(fn), functions which are labeled as exit calls. - * - * In addition, the variables defined using DEFINE_PERCPU_FIRST are - * also not included, which currently includes: - * - * 1. fixed_percpu_data - */ - if (!addr) - continue; + sym_name = elf_sym__name(sym, btfe->symtab); + if (!btf_name_valid(sym_name)) { + dump_invalid_symbol("Found symbol of invalid name when encoding btf", + sym_name, btf_elf__verbose, btf_elf__force); + if (btf_elf__force) + return 0; + return -1; + } - size = elf_sym__size(&sym); - if (!size) - continue; /* ignore zero-sized symbols */ + if (btf_elf__verbose) + printf("Found per-CPU symbol '%s' at address 0x%lx\n", sym_name, addr); - sym_name = elf_sym__name(&sym, btfe->symtab); - if (!btf_name_valid(sym_name)) { - dump_invalid_symbol("Found symbol of invalid name when encoding btf", - sym_name, btf_elf__verbose, btf_elf__force); - if (btf_elf__force) - continue; - return -1; - } + if (percpu_var_cnt == MAX_PERCPU_VAR_CNT) { + fprintf(stderr, "Reached the limit of per-CPU variables: %d\n", + MAX_PERCPU_VAR_CNT); + return -1; + } + percpu_vars[percpu_var_cnt].addr = addr; + percpu_vars[percpu_var_cnt].sz = size; + percpu_vars[percpu_var_cnt].name = sym_name; + percpu_var_cnt++; - if (btf_elf__verbose) - printf("Found per-CPU symbol '%s' at address 0x%lx\n", sym_name, addr); + return 0; +} + +static int collect_symbols(struct btf_elf *btfe, bool collect_percpu_vars) +{ + uint32_t core_id; + GElf_Sym sym; - if (percpu_var_cnt == MAX_PERCPU_VAR_CNT) { - fprintf(stderr, "Reached the limit of per-CPU variables: %d\n", - MAX_PERCPU_VAR_CNT); + /* cache variables' addresses, preparing for searching in symtab. */ + percpu_var_cnt = 0; + + /* search within symtab for percpu variables */ + elf_symtab__for_each_symbol(btfe->symtab, core_id, sym) { + if (collect_percpu_vars && collect_percpu_var(btfe, &sym)) return -1; - } - percpu_vars[percpu_var_cnt].addr = addr; - percpu_vars[percpu_var_cnt].sz = size; - percpu_vars[percpu_var_cnt].name = sym_name; - percpu_var_cnt++; } - if (percpu_var_cnt) - qsort(percpu_vars, percpu_var_cnt, sizeof(percpu_vars[0]), percpu_var_cmp); + if (collect_percpu_vars) { + if (percpu_var_cnt) + qsort(percpu_vars, percpu_var_cnt, sizeof(percpu_vars[0]), percpu_var_cmp); - if (btf_elf__verbose) - printf("Found %d per-CPU variables!\n", percpu_var_cnt); + if (btf_elf__verbose) + printf("Found %d per-CPU variables!\n", percpu_var_cnt); + } return 0; } @@ -347,7 +357,7 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force, if (!btfe) return -1; - if (!skip_encoding_vars && find_all_percpu_vars(btfe)) + if (collect_symbols(btfe, !skip_encoding_vars)) goto out; has_index_type = false;