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, URIBL_BLOCKED,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 67C48C433DF for ; Wed, 19 Aug 2020 19:17:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BC1820882 for ; Wed, 19 Aug 2020 19:17:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RqgI8CJy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727047AbgHSTRr (ORCPT ); Wed, 19 Aug 2020 15:17:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727013AbgHSTRX (ORCPT ); Wed, 19 Aug 2020 15:17:23 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95F92C061383 for ; Wed, 19 Aug 2020 12:17:23 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id w11so26839131ybi.23 for ; Wed, 19 Aug 2020 12:17:23 -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=/urKDqIkN4zGAhl6LxHMUbH10s5ZvVFc504ba3S5u7E=; b=RqgI8CJyXmWUn6Vo8lcLGmL7Sryn+W/FkZ33sxWqlgyz8meu39k4+6oomx7QFIBp3x Gg+82ihdMho3l7JJ+S2CfjEP3vQubdhyeoQjj85loSSZleZOVl/jOK3cGE8XEH01Ej2N AbQ/Vy7C7JnBDZKmbQ+iklaXV4MNxz3nqNMJxtOowSWnBqpDLp9YXD8p4zPXjqRgGid9 DF9aV54NmI8wKPj4ZWIE4q6Hj/KIDGSRh80b9cn08g+O8nK8QAGEuQ1iYxBDUmPybqOx 5zO6eUDXW1sIoB9BFjqIqf3ncr2pKUn9kYElgbeTJbWgIVBEyg7Xn7mdJSFdCsmpBLdU DioQ== 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=/urKDqIkN4zGAhl6LxHMUbH10s5ZvVFc504ba3S5u7E=; b=OIGyrb63RCfDt3k+SqvizN94nLw1b1d7+ZhY9fGddu3lrXx4yt6XtC7Dnpf2dK1Ako py36mmhHmDyWJOdXgz+Ar4T48npZeFuTBRRtfm6yLIytag6DHGfMUIpjVsTXng4kR9/7 ncVPDKyZRvp4EDCz2S71re2qz7UuCRnZvX6djNga1owKQWNdEB7ATQoc7CoyVQzdWPAk /B+lI3fXruaEfF6kSz33QTZ7DNDqq7ANZk2hMgDDiCJDyUKxCk2HsdyWkJxNF3m9X9vT nc0h2ykz1i6PRZNAP3v2D94vr1V60/t77iuw6sExZC+pkXg4AWK+GKYU2Gl7DYMAw+si m5ww== X-Gm-Message-State: AOAM532HRCAR7vkZc4Iuf4y5WgqrDNZWC80nQ70+BtldQIT+TCE6Y8LL QRLox7yzMzA/PUiFcYNL+phRLQ3mPhMlI4b63W0= X-Google-Smtp-Source: ABdhPJxkKEkPVTHl269NKfdD2vrGr8Zp3w5z/UJIqWfoTv/OqXKdyliMdkTMwO8mqpQXuu+Uw3MDyewftRdnreJ7fJE= X-Received: by 2002:a25:c2c7:: with SMTP id s190mr34810966ybf.161.1597864642671; Wed, 19 Aug 2020 12:17:22 -0700 (PDT) Date: Wed, 19 Aug 2020 12:16:53 -0700 In-Reply-To: <20200819191654.1130563-1-ndesaulniers@google.com> Message-Id: <20200819191654.1130563-5-ndesaulniers@google.com> Mime-Version: 1.0 References: <20200819191654.1130563-1-ndesaulniers@google.com> X-Mailer: git-send-email 2.28.0.297.g1956fa8f8d-goog Subject: [PATCH v2 4/5] x86/boot: use -fno-builtin-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 We're reverting commit 5f074f3e192f ("lib/string.c: implement a basic bcmp") in favor of -fno-builtin-bcmp. Remove the additional definition here, too. arch/x86/purgatory/Makefile uses -ffreestanding, so there's no risk of this libcall optimization occurring for arch/x86/boot/purgatory.ro. arch/x86/boot/Makefile resets KBUILD_CFLAGS, so make sure to reset this flag that was set for the top level Makefile. Fixes: 4ce97317f41d ("x86/purgatory: Do not use __builtin_memcpy and __builtin_memset") Reviewed-by: Kees Cook Signed-off-by: Nick Desaulniers --- arch/x86/boot/Makefile | 1 + arch/x86/boot/string.c | 8 -------- 2 files changed, 1 insertion(+), 8 deletions(-) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index fe605205b4ce..ef7f15bfceab 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -70,6 +70,7 @@ KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables +KBUILD_CFLAGS += -fno-builtin-bcmp GCOV_PROFILE := n UBSAN_SANITIZE := n diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c index 8a3fff9128bb..23d91aa7691e 100644 --- a/arch/x86/boot/string.c +++ b/arch/x86/boot/string.c @@ -37,14 +37,6 @@ int memcmp(const void *s1, const void *s2, size_t len) return diff; } -/* - * Clang may lower `memcmp == 0` to `bcmp == 0`. - */ -int bcmp(const void *s1, const void *s2, size_t len) -{ - return memcmp(s1, s2, len); -} - int strcmp(const char *str1, const char *str2) { const unsigned char *s1 = (const unsigned char *)str1; -- 2.28.0.297.g1956fa8f8d-goog