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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 BDC6FC433DF for ; Mon, 17 Aug 2020 22:02:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B7CD2072E for ; Mon, 17 Aug 2020 22:02:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SbD3KyAR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729324AbgHQWCh (ORCPT ); Mon, 17 Aug 2020 18:02:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729255AbgHQWC3 (ORCPT ); Mon, 17 Aug 2020 18:02:29 -0400 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 346FAC061346 for ; Mon, 17 Aug 2020 15:02:28 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id e3so10934288pgs.3 for ; Mon, 17 Aug 2020 15:02:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=LSuJ265AIHX3+q/k1a/Z37Re9kn2OGu2g13JwIWu2AE=; b=SbD3KyARYSzP8T36XfR3PSHqanZP7aAf5JDZqJYGiBhLP4rKgTLGRPXAppDrg1sTl5 A9PvTf6cNxt3GdMtU0KSlh7GmwXcTGaesG0K0g3xTu8P8G7joqPf8pqpMrmBKfoEbjd6 PJZiF857IQv87kAQWEqVMLXO4K6nHk5cg7ima1rEYeAq7T29BawPJFtEEEoh/Txl8pWT TrKCydEAn6SB0ypdUtIwcrhW5JGeTybo2eNnMFkTEVjjLmLpnN6izcqwyzozEc5lZzCj z4Y3sjmLT2yMtfeZS2VtmD78guFvtoZ+47uKaDzT/rFKbG0PUt3gc85QKli8876L8iga 1+dg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=LSuJ265AIHX3+q/k1a/Z37Re9kn2OGu2g13JwIWu2AE=; b=lziEukcoGb4AMKe2TpT8asnLDHyp4ao+2e+b2CP4MZQB4XHcWHpAdrq0WYjZv3dz9K RNhO3TeVl8o5G6vhxjOYj8LNjhpUj4mbsjchZs09fKTps/WVmj/bGEh3mwOuyod8dBet w6lQRPxGUJwVw5wRAPz21h3gTofJCCZRnsZR46PVCoH/BKxnMzR7GSECVGnFXO1791cj /R4X9jmhNpevYRkDroXwGth1mQhzPQoq+esT7QLxcwkh29iPXbEmh2hBYTra0LabHgZR ixOONJNMTADpYB818sY64Qreu12dEXCFxY7T8zcajQCEsAFQi3Xp6DwvLCddbaP+xB28 y3ug== X-Gm-Message-State: AOAM530U5qFsnIQZykr6oNeBOFTEoH0aJlIfDGcpvc2EbUV9ZbsQZ88J pZOOQ1gYyitzEh567rX06pBwgr2Fg28wXZMbtNs= X-Google-Smtp-Source: ABdhPJz0bjSGZm+ZdrPGtRtCXBpejLmPe6KZV95C2FmKOvxUsvXkFXAWlKgIMYvfMsU+gy0mVusHMS/N02PzQC8v5VA= X-Received: by 2002:a62:86ca:: with SMTP id x193mr12601031pfd.152.1597701747572; Mon, 17 Aug 2020 15:02:27 -0700 (PDT) Date: Mon, 17 Aug 2020 15:02:10 -0700 In-Reply-To: <20200817220212.338670-1-ndesaulniers@google.com> Message-Id: <20200817220212.338670-3-ndesaulniers@google.com> Mime-Version: 1.0 References: <20200817220212.338670-1-ndesaulniers@google.com> X-Mailer: git-send-email 2.28.0.220.ged08abb693-goog Subject: [PATCH 2/4] Revert "lib/string.c: implement a basic bcmp" From: Nick Desaulniers To: Masahiro Yamada , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov Cc: Michal Marek , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Kees Cook , Tony Luck , Dmitry Vyukov , Michael Ellerman , Joe Perches , Joel Fernandes , Daniel Axtens , Arvind Sankar , Andy Shevchenko , Alexandru Ardelean , Yury Norov , x86@kernel.org, "H . Peter Anvin" , Ard Biesheuvel , "Paul E . McKenney" , Daniel Kiper , Bruce Ashfield , Marco Elver , Vamshi K Sthambamkadi , Andi Kleen , Linus Torvalds , "=?UTF-8?q?D=C3=A1vid=20Bolvansk=C3=BD?=" , Eli Friedman , Nick Desaulniers Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This reverts commit 5f074f3e192f10c9fade898b9b3b8812e3d83342. Use `-fno-builtin-bcmp` instead. The issue with using `-fno-builtin-*` flags was that they were not retained during an LTO link with LLVM. This was fixed in clang-11 by https://reviews.llvm.org/D71193 (0508c994f0b14144041f2cfd3ba9f9a80f03de08), which is also the minimum supported version of clang for LTO. Signed-off-by: Nick Desaulniers --- Makefile | 1 + include/linux/string.h | 3 --- lib/string.c | 20 -------------------- 3 files changed, 1 insertion(+), 23 deletions(-) diff --git a/Makefile b/Makefile index 211a1b6f6478..722ff5864275 100644 --- a/Makefile +++ b/Makefile @@ -964,6 +964,7 @@ endif # to provide implementations of these routines, then prevent the compiler from # emitting calls to what will be undefined symbols. KBUILD_CFLAGS += -fno-builtin-stpcpy +KBUILD_CFLAGS += -fno-builtin-bcmp # include additional Makefiles when needed include-y := scripts/Makefile.extrawarn diff --git a/include/linux/string.h b/include/linux/string.h index b1f3894a0a3e..f3bdb74bc230 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -155,9 +155,6 @@ extern void * memscan(void *,int,__kernel_size_t); #ifndef __HAVE_ARCH_MEMCMP extern int memcmp(const void *,const void *,__kernel_size_t); #endif -#ifndef __HAVE_ARCH_BCMP -extern int bcmp(const void *,const void *,__kernel_size_t); -#endif #ifndef __HAVE_ARCH_MEMCHR extern void * memchr(const void *,int,__kernel_size_t); #endif diff --git a/lib/string.c b/lib/string.c index 6012c385fb31..69328b8353e1 100644 --- a/lib/string.c +++ b/lib/string.c @@ -922,26 +922,6 @@ __visible int memcmp(const void *cs, const void *ct, size_t count) EXPORT_SYMBOL(memcmp); #endif -#ifndef __HAVE_ARCH_BCMP -/** - * bcmp - returns 0 if and only if the buffers have identical contents. - * @a: pointer to first buffer. - * @b: pointer to second buffer. - * @len: size of buffers. - * - * The sign or magnitude of a non-zero return value has no particular - * meaning, and architectures may implement their own more efficient bcmp(). So - * while this particular implementation is a simple (tail) call to memcmp, do - * not rely on anything but whether the return value is zero or non-zero. - */ -#undef bcmp -int bcmp(const void *a, const void *b, size_t len) -{ - return memcmp(a, b, len); -} -EXPORT_SYMBOL(bcmp); -#endif - #ifndef __HAVE_ARCH_MEMSCAN /** * memscan - Find a character in an area of memory. -- 2.28.0.220.ged08abb693-goog