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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 D8C35C1B0E3 for ; Wed, 11 Jul 2018 20:37:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8831C20C0C for ; Wed, 11 Jul 2018 20:37:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="fuPvhDmy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8831C20C0C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390312AbeGKUmi (ORCPT ); Wed, 11 Jul 2018 16:42:38 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:41137 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390286AbeGKUmh (ORCPT ); Wed, 11 Jul 2018 16:42:37 -0400 Received: by mail-pg1-f196.google.com with SMTP id z8-v6so1748325pgu.8 for ; Wed, 11 Jul 2018 13:36:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=zbkP//JFKhVRhh8B5f8winKslJMgyIBJ8s7W/9N89AE=; b=fuPvhDmyzhG8j+GJ5IeIi7yZeY/GqMYyert8l2k//jXMBO3sU0SDBGII8thD440TLL H7E1gaHn3R6Iyp783UtiV3WLnEncJCEBAtL9to9l+o9L6/TJ41cezeme41IseUe+4oT+ clkBXCvHTpVBRlYWPBpF4E5J8jAi4DjUZNhBs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=zbkP//JFKhVRhh8B5f8winKslJMgyIBJ8s7W/9N89AE=; b=Zd5UUpZ8MsXS6o9ToNfP2puVUN22l1YfhtNYDYI3bnv4AhxT4Je6pkgFHadTZFaVFv ot0JNuu5Zg0OZJQ6pgZe2cj3XmYWX9PPEYJDQJ51ku1FCctOKM38lywMSxz8HLUfyxyz 17q7M89/kjWRw4oopsw/upmM1mOV5+TNDZ8VJGxjjzZUI2qFB25B3NceUMj7Fswi2wVC oHKe7nAApwPTX2XIpJ20RXKJNEYjQzTozEQU+nXMt+Q8lwYRyMVAYHDMjU/0o+Pw1Udt hSs+NNTNQyk+f03H0ACp14j8qMaBNlEm5d1fT/9Rh3FtwkNJ/cMkUg/5i5N+8GadrVM8 NETA== X-Gm-Message-State: AOUpUlF5KXFRHivuLS7SdxBniY4CSLGHSx1YM/mVI3N7lcZGm24cIhaw Ii18Fnd48OEeUosJyOSXix8P7Q== X-Google-Smtp-Source: AAOMgpepV5D3hXGjQPONIQWKHnKjYnMEWl4+AlUQZK99ilxTACsZh9+0+dEBeo0kkAvkBrSh5sgV+A== X-Received: by 2002:a62:c699:: with SMTP id x25-v6mr180974pfk.16.1531341393327; Wed, 11 Jul 2018 13:36:33 -0700 (PDT) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id y85-v6sm17725654pfa.170.2018.07.11.13.36.26 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 11 Jul 2018 13:36:28 -0700 (PDT) From: Kees Cook To: Herbert Xu Cc: Kees Cook , "Gustavo A. R. Silva" , Arnd Bergmann , Eric Biggers , Alasdair Kergon , Giovanni Cabiddu , Lars Persson , Mike Snitzer , Rabin Vincent , Tim Chen , "David S. Miller" , Masahiro Yamada , linux-crypto@vger.kernel.org, qat-linux@intel.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH v4 10/14] kbuild: Introduce FRAME_WARN_BUMP_FLAG Date: Wed, 11 Jul 2018 13:36:15 -0700 Message-Id: <20180711203619.1020-11-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180711203619.1020-1-keescook@chromium.org> References: <20180711203619.1020-1-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When building with CONFIG_FRAME_WARN, it is sometimes useful to give certain compilation units small additional headroom. This is normally useful when VLA removal exposes a large stack allocation, especially with FRAME_WARN at 1024 or smaller. This adds 20%. Signed-off-by: Kees Cook --- Makefile | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Makefile b/Makefile index c9132594860b..06fe93edd052 100644 --- a/Makefile +++ b/Makefile @@ -684,7 +684,13 @@ endif ifneq ($(CONFIG_FRAME_WARN),0) KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN}) +# Small code (mostly exposed by VLA removal) needs some additional +# headroom, especially for a FRAME_WARN of 1024. This adds 20% which +# can be used by the CFLAG_FRAME_WARN_BUMP option. +FRAME_WARN_BUMP_SIZE := $(shell expr $(CONFIG_FRAME_WARN) / 5 + $(CONFIG_FRAME_WARN)) +FRAME_WARN_BUMP_FLAG := $(call cc-option,-Wframe-larger-than=$(FRAME_WARN_BUMP_SIZE)) endif +export FRAME_WARN_BUMP_FLAG stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector stackp-flags-$(CONFIG_STACKPROTECTOR) := -fstack-protector -- 2.17.1