From patchwork Sun Jul 28 10:09:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Denis Efremov (Oracle)" X-Patchwork-Id: 11062927 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9B7FB13A0 for ; Sun, 28 Jul 2019 10:09:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 811B9287E5 for ; Sun, 28 Jul 2019 10:09:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7038528971; Sun, 28 Jul 2019 10:09:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E0838287E5 for ; Sun, 28 Jul 2019 10:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725975AbfG1KJu (ORCPT ); Sun, 28 Jul 2019 06:09:50 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:54084 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725961AbfG1KJu (ORCPT ); Sun, 28 Jul 2019 06:09:50 -0400 Received: by mail-wm1-f68.google.com with SMTP id x15so51344539wmj.3; Sun, 28 Jul 2019 03:09:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=UDJukCltcBoDIamYjAzjZ4beReUXQTV1IlWv2RKZBIo=; b=PHWpmSHGn0qN1rLjzViuNkJnXzq1f2nCbIiQUoEWGWWkU4iuellFtBzdMZiyWoefzg 4TuZzXX6Q7uaBT9smt7ECPUF7e/m6qEbq1NXHxsWyIIGqEy5XjuC6RD3Lf38uXdA+P+r fg9u8iLtg4aBOwifwonfyXY28Dn/qISObjF/mCThaeKc7jZ4i286Gsia+rbIZtOlqUJX BNHcTP/cgzAspT8AaENX/8bZ431ci9ubnxXXdixSbfYHkQc/c3vJFM6ZI2uqxI9Oe+lh cBks8/x1ztJJLwJEu4RQuJAzoJu910wtV9VzebG4/aHGuBpzaquuCNlW8BSTZzreAl0O m/IQ== X-Gm-Message-State: APjAAAW1JPkyjTM4SWtLfQaaU+BpihT8qSqXE9nrRNQlgLCtCF0PjaNr qc9A2UNhVJa5EoX6P36/fPw= X-Google-Smtp-Source: APXvYqwoz6Z+wgrSR4vFsGkD7BNjOhJJW1on8ALUEDE+NyuhaIUMaLGwF3tD4pd4jlaK7QTI3b9slw== X-Received: by 2002:a1c:cb43:: with SMTP id b64mr92535116wmg.135.1564308587840; Sun, 28 Jul 2019 03:09:47 -0700 (PDT) Received: from localhost.localdomain (broadband-188-32-48-208.ip.moscow.rt.ru. [188.32.48.208]) by smtp.googlemail.com with ESMTPSA id y16sm124811890wrg.85.2019.07.28.03.09.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 28 Jul 2019 03:09:46 -0700 (PDT) From: Denis Efremov To: Masahiro Yamada Cc: Denis Efremov , Michal Marek , Emil Velikov , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] modpost: check for static EXPORT_SYMBOL* functions Date: Sun, 28 Jul 2019 13:09:06 +0300 Message-Id: <20190728100906.18847-1-efremov@linux.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190714152817.24693-1-efremov@linux.com> References: <20190714152817.24693-1-efremov@linux.com> MIME-Version: 1.0 Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch adds a check to warn about static EXPORT_SYMBOL* functions during the modpost. In most of the cases, a static symbol marked for exporting is an odd combination that should be fixed either by deleting the exporting mark or by removing the static attribute and adding the appropriate declaration to headers. This check could help to detect the following problems: 1. 550113d4e9f5 ("i2c: add newly exported functions to the header, too") 2. 54638c6eaf44 ("net: phy: make exported variables non-static") 3. 98ef2046f28b ("mm: remove the exporting of totalram_pages") 4. 73df167c819e ("s390/zcrypt: remove the exporting of ap_query_configuration") 5. a57caf8c527f ("sunrpc/cache: remove the exporting of cache_seq_next") 6. e4e4730698c9 ("crypto: skcipher - remove the exporting of skcipher_walk_next") 7. 14b4c48bb1ce ("gve: Remove the exporting of gve_probe") 8. 9b79ee9773a8 ("scsi: libsas: remove the exporting of sas_wait_eh") 9. ... Build time impact, allmodconfig, Dell XPS 15 9570 (measurements 3x): $ make mrproper; make allmodconfig; time make -j12; \ git checkout HEAD~1; \ make mrproper; make allmodconfig; time make -j12 1. (with patch) 17635,94s user 1895,54s system 1085% cpu 29:59,22 total (w/o patch) 17275,42s user 1803,87s system 1112% cpu 28:35,66 total 2. (with patch) 17369,51s user 1763,28s system 1111% cpu 28:41,47 total (w/o patch) 16880,50s user 1670,93s system 1113% cpu 27:46,56 total 3. (with patch) 17937,88s user 1842,53s system 1109% cpu 29:42,26 total (w/o patch) 17267,55s user 1725,09s system 1111% cpu 28:28,17 total Thus, the current implementation adds approx. 1 min for allmodconfig. Acked-by: Emil Velikov Signed-off-by: Denis Efremov --- scripts/mod/modpost.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index f277e116e0eb..85e885235c96 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -169,6 +169,7 @@ struct symbol { unsigned int kernel:1; /* 1 if symbol is from kernel * (only for external modules) **/ unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */ + unsigned int is_static:1; /* 1 if symbol is not global */ enum export export; /* Type of export */ char name[0]; }; @@ -201,6 +202,7 @@ static struct symbol *alloc_symbol(const char *name, unsigned int weak, strcpy(s->name, name); s->weak = weak; s->next = next; + s->is_static = 1; return s; } @@ -1980,6 +1982,22 @@ static void read_symbols(const char *modname) handle_modversions(mod, &info, sym, symname); handle_moddevtable(mod, &info, sym, symname); } + + // check for static EXPORT_SYMBOL_* functions && global vars + for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { + unsigned char bind = ELF_ST_BIND(sym->st_info); + unsigned char type = ELF_ST_TYPE(sym->st_info); + + if (type == STT_OBJECT || type == STT_FUNC) { + struct symbol *s = + find_symbol(remove_dot(info.strtab + + sym->st_name)); + + if (s && (bind == STB_GLOBAL || bind == STB_WEAK)) + s->is_static = 0; + } + } + if (!is_vmlinux(modname) || vmlinux_section_warnings) check_sec_ref(mod, modname, &info); @@ -2425,6 +2443,7 @@ int main(int argc, char **argv) char *dump_write = NULL, *files_source = NULL; int opt; int err; + size_t n; struct ext_sym_list *extsym_iter; struct ext_sym_list *extsym_start = NULL; @@ -2520,6 +2539,19 @@ int main(int argc, char **argv) if (sec_mismatch_count && sec_mismatch_fatal) fatal("modpost: Section mismatches detected.\n" "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); + for (n = 0; n < SYMBOL_HASH_SIZE; n++) { + struct symbol *s = symbolhash[n]; + + while (s) { + if (s->is_static) + warn("\"%s\" [%s] is the static %s\n", + s->name, s->module->name, + export_str(s->export)); + + s = s->next; + } + } + free(buf.p); return err;