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 X-Spam-Level: X-Spam-Status: No, score=-26.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 4CAECC433FE for ; Fri, 11 Dec 2020 20:36:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC84323137 for ; Fri, 11 Dec 2020 20:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390228AbgLKSth (ORCPT ); Fri, 11 Dec 2020 13:49:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394216AbgLKSsO (ORCPT ); Fri, 11 Dec 2020 13:48:14 -0500 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05051C0619D4 for ; Fri, 11 Dec 2020 10:46:48 -0800 (PST) Received: by mail-pg1-x549.google.com with SMTP id g24so7086297pgh.14 for ; Fri, 11 Dec 2020 10:46:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=D6dzW9Nv9PxzQobvhFlQDWUjMujzTJKPO9b+q7PtBxA=; b=j80QiI4Ul6UgEkfC+jupmsvTxkEELd8wbgUjUZ6N8GZBz3X4UojppIFANKFCwEcr0b hjg7atDwt+r6dl376cixss8x61cmNs3p6kdE0NH0HxFb1RFB4vQfxhmnXPW46RXzb3jX w/C2Yv2wPOS6QjdjcS5NeKPbqbdp8shMph/o4hHfNZ5sJb5N3Ar0+qPkmusVLmg+5im/ FXu/NZwu9TMocoPetDYE2QWKb90ZDlr4lbZ3N2VjoMkHvJaSPTfqO5DKNCfYjLKaMtOp PjFKT07Sh00XUoerVDLql1CWKexmWjEKEMlFf7a6DuR4Wtg99akEQhhQl7HctgCVr2eD quKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=D6dzW9Nv9PxzQobvhFlQDWUjMujzTJKPO9b+q7PtBxA=; b=qI4YPOBvKY1mUe9uP8JJkiU+0S1X9+f3tSOL4jYnFVQgfulYtWTBy9XZfHrLnMnZ/S 0k4wZvX0jl0MXVw20vLTGYN+cIFsvEPNV/QaW2EfQtkeLtRnSKmbxdJju12Ck6y5Y/Px gY9zwPYmwPsRbZvDMOuluIwz2lJBHnWBlWEiyXkWJ1qBoXy20PQfjB1OkpiYpaJjcfGB SU5iwgPAixCmS+4F08njZbdhDTuxuSMBAs/il7jQo5DXV1Ju6SqEtwn9xJysZHrSQOSb 6dO85Pp98zl4G/CxcQSKjwvK+wC96xxbhca1jM8fpYdpvbsm0VACnd+MzmTwVdW1WHrU pZVg== X-Gm-Message-State: AOAM532E/JreS4oWg8F7eG2JBY8CsinnG+ZM3Q+5bXWqhRe5gQPsxUwW 9dO2co7zMx5vB37toLF8IVPZM/521U57yZu3sEs= X-Google-Smtp-Source: ABdhPJzTxDOAZu/cl6nSaAjpW3k/LNI+wnG91vRp8xhL+7QirY0I3Vi1skb6ONtaVKsVxERXnDfxMhqkc0oDgftg5yE= Sender: "samitolvanen via sendgmr" X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a17:902:bb8c:b029:d9:261:5809 with SMTP id m12-20020a170902bb8cb02900d902615809mr3908181pls.29.1607712407508; Fri, 11 Dec 2020 10:46:47 -0800 (PST) Date: Fri, 11 Dec 2020 10:46:23 -0800 In-Reply-To: <20201211184633.3213045-1-samitolvanen@google.com> Message-Id: <20201211184633.3213045-7-samitolvanen@google.com> Mime-Version: 1.0 References: <20201211184633.3213045-1-samitolvanen@google.com> X-Mailer: git-send-email 2.29.2.576.ga3fc446d84-goog Subject: [PATCH v9 06/16] kbuild: lto: add a default list of used symbols From: Sami Tolvanen To: Masahiro Yamada , Steven Rostedt , Will Deacon Cc: Josh Poimboeuf , Peter Zijlstra , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org With CONFIG_LTO_CLANG, LLVM bitcode has not yet been compiled into a binary when the .mod files are generated, which means they don't yet contain references to certain symbols that will be present in the final binaries. This includes intrinsic functions, such as memcpy, memmove, and memset [1], and stack protector symbols [2]. This change adds a default symbol list to use with CONFIG_TRIM_UNUSED_KSYMS when Clang's LTO is used. [1] https://llvm.org/docs/LangRef.html#standard-c-c-library-intrinsics [2] https://llvm.org/docs/LangRef.html#llvm-stackprotector-intrinsic Signed-off-by: Sami Tolvanen --- init/Kconfig | 1 + scripts/lto-used-symbollist | 5 +++++ 2 files changed, 6 insertions(+) create mode 100644 scripts/lto-used-symbollist diff --git a/init/Kconfig b/init/Kconfig index 0872a5a2e759..e88c919c1bf1 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2297,6 +2297,7 @@ config TRIM_UNUSED_KSYMS config UNUSED_KSYMS_WHITELIST string "Whitelist of symbols to keep in ksymtab" depends on TRIM_UNUSED_KSYMS + default "scripts/lto-used-symbollist" if LTO_CLANG help By default, all unused exported symbols will be un-exported from the build when TRIM_UNUSED_KSYMS is selected. diff --git a/scripts/lto-used-symbollist b/scripts/lto-used-symbollist new file mode 100644 index 000000000000..38e7bb9ebaae --- /dev/null +++ b/scripts/lto-used-symbollist @@ -0,0 +1,5 @@ +memcpy +memmove +memset +__stack_chk_fail +__stack_chk_guard -- 2.29.2.576.ga3fc446d84-goog