From patchwork Tue Sep 29 21:46:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11807133 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 08465139F for ; Tue, 29 Sep 2020 21:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D329C20789 for ; Tue, 29 Sep 2020 21:48:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Imh3zKnl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728943AbgI2Vsh (ORCPT ); Tue, 29 Sep 2020 17:48:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729218AbgI2Vrp (ORCPT ); Tue, 29 Sep 2020 17:47:45 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B92BC0613A6 for ; Tue, 29 Sep 2020 14:47:36 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id s9so108666qks.21 for ; Tue, 29 Sep 2020 14:47:36 -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=19TlqdLHcWDTmI9u6TYfXzttwjA+Dmg1Ug41aa4j6uk=; b=Imh3zKnlf2nNedw1LEfjqkhMgHeK71AVCBTejoYYCUi6PprkQk88VjzniR9FHbE1XH A/II2EqGYTLeEsZmDBTUvx/jf+f+d3tAzBZHwlmB+xrtw4+Z2cxN48VSSgTsz6Lj1ySD au/YMsmvn17ksVH6myXy9K4BV+sk2zN+Jafs8YeXGbiW03h8j+LFgn5hDUVmYV3j8Dwy l5E/DW5nnZBvg1KomyJxVSBEJYPTHNIcVL8vsj7kyNFLz2DfWMaRIUqUjSw2EGwIoKgP 4DyUsfcM0sMb+V2Mle0bHYnakGr+xwU5kaLeprG/fr2kotBwhV+W2FpWkSGvxSxGnZ4G GCHA== 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=19TlqdLHcWDTmI9u6TYfXzttwjA+Dmg1Ug41aa4j6uk=; b=Le4ZNcSJ+2GAa5DMvJBc67X518d1phH8fEPDb4gjaImBWvMwK45Ceo3mhAaNuQLCKA NxO85f7qkIoxjQ6G3d3bdGbzC/rTRifNTBBbtkZlmvrlT46mufPBLF4nf/H883No7eLl TpLhDotDtTcSspm12IuOgQNde3+GcghNFTgzViEnNM8xDZP7IfF0H9YDe+OnGkMlYNDq g6+Cp1zIbynRlUAxK468Mg4zXJnvboZiJRazEvtxBltCrTkgli+s9+gSk9pHHayjFy53 dUCLxL8Mq71RwDqrBEXe7Gr6ipujITC+xk7v6gcipaIbU9znCFJ+zMG669aw94QVj78U rzDg== X-Gm-Message-State: AOAM530saU888H87WdH+9k8JcYeSaAMOubJkV0FYeSl8tkH9aRnm3zdg OWBJcg4NPgeekOgEN3JYtzRyBSjTzpFTYkdhbN4= X-Google-Smtp-Source: ABdhPJwlpWalcJXzE9B3fP2Zu3YiL4EE4FmSmcZUIR72EOxrhafPHlFtIMBSkfJpTgmFk8E2fcAes0b129xUXc5bjus= 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:ad4:4594:: with SMTP id x20mr6549973qvu.4.1601416055400; Tue, 29 Sep 2020 14:47:35 -0700 (PDT) Date: Tue, 29 Sep 2020 14:46:29 -0700 In-Reply-To: <20200929214631.3516445-1-samitolvanen@google.com> Message-Id: <20200929214631.3516445-28-samitolvanen@google.com> Mime-Version: 1.0 References: <20200929214631.3516445-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.709.gb0816b6eb0-goog Subject: [PATCH v4 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 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@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)