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From: Kees Cook <keescook@chromium.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kees Cook <keescook@chromium.org>,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
	Arnd Bergmann <arnd@arndb.de>, Eric Biggers <ebiggers@google.com>,
	Alasdair Kergon <agk@redhat.com>,
	Giovanni Cabiddu <giovanni.cabiddu@intel.com>,
	Lars Persson <larper@axis.com>, Mike Snitzer <snitzer@redhat.com>,
	Rabin Vincent <rabinv@axis.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	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	[thread overview]
Message-ID: <20180711203619.1020-11-keescook@chromium.org> (raw)
In-Reply-To: <20180711203619.1020-1-keescook@chromium.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 <keescook@chromium.org>
---
 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


  parent reply	other threads:[~2018-07-11 20:37 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-11 20:36 [PATCH v4 00/14] crypto: Remove VLA usage Kees Cook
2018-07-11 20:36 ` [PATCH v4 01/14] crypto: xcbc: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 02/14] crypto: cbc: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 03/14] crypto: shash: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 04/14] dm integrity: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 05/14] crypto: ahash: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 06/14] dm verity fec: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 07/14] crypto alg: Introduce generic max blocksize and alignmask Kees Cook
2018-07-11 20:36 ` [PATCH v4 08/14] crypto: qat: Remove VLA usage Kees Cook
2018-07-11 20:36 ` [PATCH v4 09/14] crypto: shash: Remove VLA usage in unaligned hashing Kees Cook
2018-07-11 20:36 ` Kees Cook [this message]
2018-07-11 20:36 ` [PATCH v4 11/14] treewide: Prepare to remove VLA usage for AHASH_REQUEST_ON_STACK Kees Cook
2018-07-12 16:02   ` Arnd Bergmann
2018-07-12 20:17     ` Kees Cook
2018-07-12 21:38       ` Arnd Bergmann
2018-07-13  0:40     ` Herbert Xu
2018-07-13  3:33       ` Kees Cook
2018-07-13  3:44         ` Herbert Xu
2018-07-13  5:17           ` Kees Cook
2018-07-13  5:20             ` Herbert Xu
2018-07-13  6:00               ` Kees Cook
2018-07-13 10:14                 ` Arnd Bergmann
2018-07-15  4:28                   ` Kees Cook
2018-07-17 20:59                     ` Arnd Bergmann
2018-07-18 14:50                       ` Ard Biesheuvel
2018-07-18 15:19                         ` Ard Biesheuvel
2018-07-18 15:33                           ` Arnd Bergmann
2018-07-18 15:33                             ` Ard Biesheuvel
2018-07-19  2:51                           ` Kees Cook
2018-07-19  2:55                             ` Ard Biesheuvel
2018-07-19  3:09                               ` Kees Cook
2018-07-19  3:13                                 ` Ard Biesheuvel
2018-07-19 14:54                                   ` Ard Biesheuvel
2018-07-19 18:44                                     ` Kees Cook
2018-07-13  6:16       ` Kees Cook
2018-07-13  6:22         ` Herbert Xu
2018-07-14  3:07           ` Kees Cook
2018-07-15  2:44             ` Herbert Xu
2018-07-15  2:59               ` Kees Cook
2018-07-16  0:01                 ` Herbert Xu
2018-07-16  3:39                   ` Kees Cook
2018-07-16  7:24                     ` Arnd Bergmann
2018-07-11 20:36 ` [PATCH v4 12/14] crypto: ahash: Remove " Kees Cook
2018-07-11 20:36 ` [PATCH v4 13/14] rxrpc: Prepare to remove VLA usage for SKCIPHER_REQUEST_ON_STACK Kees Cook
2018-07-12 15:11   ` Arnd Bergmann
2018-07-12 20:23     ` Kees Cook
2018-07-12 20:30       ` Kees Cook
2018-07-12 21:15         ` Arnd Bergmann
2018-07-12 21:38           ` Kees Cook
2018-07-12 21:28   ` David Howells
2018-07-12 21:34     ` Kees Cook
2018-07-12 22:05   ` David Howells
2018-07-11 20:36 ` [PATCH v4 14/14] crypto: skcipher: Remove " Kees Cook

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