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=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 17595C2D0A2 for ; Fri, 9 Oct 2020 16:15:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CAF8822261 for ; Fri, 9 Oct 2020 16:15:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Of/McM9M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389828AbgJIQPX (ORCPT ); Fri, 9 Oct 2020 12:15:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389863AbgJIQPI (ORCPT ); Fri, 9 Oct 2020 12:15:08 -0400 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9903DC0613BD for ; Fri, 9 Oct 2020 09:14:34 -0700 (PDT) Received: by mail-pf1-x449.google.com with SMTP id j5so7121504pff.6 for ; Fri, 09 Oct 2020 09:14:34 -0700 (PDT) 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=hXDRuVDCt6QcdhcOoOZPfzkgSyHjAxTz3vM4hOZGaOg=; b=Of/McM9MKCVt3xMTzgE2jLFxrK6HLM9gHntYJNTcjy9ApZaKHz0NdjwbrXXqJ0KeXL QILhcYMJykX0DmdfDMEtd1i9+jSTop+Teol7A0HSxWBP/JcipzZjeYHbk2YDLsmk1NQ5 G2UUcHyxFMpvulEN8vXHpV9R6Nt0Bh4/MBsRvGu0XRXB7N2md6vLGW5FRJ7LZH5lBvgB pDYYRrNjX76WD2872VTFDZDZcdeeeYnq5VF5RlcVhEUVYIDLvVOw1Myce0txxTVpNib1 ITGnOYce1pEF2cgi2zX7oPIqItMYk/+MigcROat7aHTJYH0uDLF+ZV1tegP02Tx/IS94 4skA== 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=hXDRuVDCt6QcdhcOoOZPfzkgSyHjAxTz3vM4hOZGaOg=; b=umglxriairaaNkGcsw8WhJZCv9sHm9wvikTHVwmJb5AUhpJ/Ip5lpEVnA3TWyeokQq xrXDWbuVkyhMr1EWIAfI4P0hCWgLiuo54XCgvaDavQNPm7cyS+9C0nq6bqz9iXr0gvUV EppvU0n9Np1HiR2jKBuYkCV0jMnI+biibBLSrtYng528vBuQJTHYVqk/rQvIzBWIfuBR 6tMP7w4AY8PvqNekQei2DFR6qI8tDeb1lX2VGVhfVJWFs2yZwPeDWSnt0yQOM0B2XH8g 9tGuHCLGu+GJ9Rh9knwzdSj7jGl+qzc74G04tH+GuRNNlREnN3fjL2dAvlm+n1hpMQ1k bLsg== X-Gm-Message-State: AOAM532wiOt0H36EgeMWhImqS7K0OzZehXzLnCHuJVLe8xU7QjJFVux4 NjZWMXqQTfeS6A4skQK08FvRczmov0rmClDjUSc= X-Google-Smtp-Source: ABdhPJyBk60af/C9C5g9kK9znnQdELrD7eCQBW2IcTXEuF7Dn8nzTsEw+V/y+nNCQlumSGoUUFgDmGGBfFH5vdLVxvs= 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:a62:c701:0:b029:142:2501:39e4 with SMTP id w1-20020a62c7010000b0290142250139e4mr13194002pfg.51.1602260074046; Fri, 09 Oct 2020 09:14:34 -0700 (PDT) Date: Fri, 9 Oct 2020 09:13:36 -0700 In-Reply-To: <20201009161338.657380-1-samitolvanen@google.com> Message-Id: <20201009161338.657380-28-samitolvanen@google.com> Mime-Version: 1.0 References: <20201009161338.657380-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v5 27/29] x86, vdso: disable LTO only for vDSO From: Sami Tolvanen To: Masahiro Yamada , Will Deacon , Steven Rostedt Cc: 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, x86@kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Disable LTO for the vDSO. Note that while we could use Clang's LTO for the 64-bit vDSO, it won't add noticeable benefit for the small amount of C code. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- arch/x86/entry/vdso/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index ecc27018ae13..9b742f21d2db 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -90,7 +90,7 @@ ifneq ($(RETPOLINE_VDSO_CFLAGS),) endif endif -$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) +$(vobjs): KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) # # vDSO code runs in userspace and -pg doesn't help with profiling anyway. @@ -148,6 +148,7 @@ KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32)) +KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic KBUILD_CFLAGS_32 += -fno-stack-protector KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) -- 2.28.0.1011.ga647a8990f-goog