From patchwork Tue Oct 13 00:32:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11834831 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 B8FC3109B for ; Tue, 13 Oct 2020 02:45:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9CA9520678 for ; Tue, 13 Oct 2020 02:45:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Q8OgoYWJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727768AbgJMAed (ORCPT ); Mon, 12 Oct 2020 20:34:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727725AbgJMAdj (ORCPT ); Mon, 12 Oct 2020 20:33:39 -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 424A2C0613BB for ; Mon, 12 Oct 2020 17:32:58 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id x14so5804915ybg.7 for ; Mon, 12 Oct 2020 17:32:58 -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=Q8OgoYWJ38A1DTeEf63Hk3c3hYYH4ZF0z/4PTOL57lC91oiRnkf9gd9B9qku6Q1r6u wJpqEn6EAi4UteX1DyN2q/JvaTTtpy84jR6VL0m2JhAl1RoRGIYWTX9l1lTaDfwxSMKw LefJJwRakxdtpPQ08/FQAf92Wa1ozzQh8P2RP2YZPMgSGdz7KcYbVYFd9TUmBqArokGv +ldWe6u3YKRcL8TPbph9eLO/Rzlrbtj3yh/gdxcr/CPwfeRwl+euqw8SSVnfC+RC6cR4 StF7LmGsoqGTDk0I/EG14+cMInf9+wTZSixivfF3ZGh1ldNUWQxtZk/Jwl6sRHt0BJIe TMlQ== 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=qtnT1vi2xsHbwDxzXbhsOBEZEIhQGhJ38e/ddfEWejohJ0lr0YmhvFaGCbhM7PpNcx vdcse8Ez/MLb5+wYHwVGcO25wbdeOqDI8vg1F2PRblhtPNcWz+XrKcQe4pQiNWfb7NXc 89MOezvVDXwqulLM5IcsP24VNUFFcxohDDgQEEBWeSiu0UoGRC3b8z7RC2iaIgYHLkMo mJfI0XQgxCyam6lCgLe5pX/sLv+EnV2Rf76EbcoVn7m8z+RdwrMo0Pz4/jsS3kD8JOYW RWEE6b54tjrG2vqYJ/n18H/Aggb3AmqyZ2pqI+BGFSZPDinPYbdT6d4C14G+bUFHX6Sg Wefw== X-Gm-Message-State: AOAM531Nois64/+j1jOHNWuUV8IspiCkpBH277Puw7ZL1SihlAxPu3Af pzDjPeNmfFmVVvZ49D+1e4p46GfeDbZfqLPMicw= X-Google-Smtp-Source: ABdhPJwbnvZ4QCf51zdpzXBwYixY461mQNfzv2AaPBdgQJxvN6CQhpCGMZEflp7FPw1Aa3EKTn0uJBFEhoLOmniOABo= 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:a25:842:: with SMTP id 63mr33820736ybi.311.1602549177444; Mon, 12 Oct 2020 17:32:57 -0700 (PDT) Date: Mon, 12 Oct 2020 17:32:01 -0700 In-Reply-To: <20201013003203.4168817-1-samitolvanen@google.com> Message-Id: <20201013003203.4168817-24-samitolvanen@google.com> Mime-Version: 1.0 References: <20201013003203.4168817-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH v6 23/25] x86, vdso: disable LTO only for vDSO From: Sami Tolvanen To: Masahiro Yamada , Steven Rostedt Cc: Will Deacon , 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)