From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kbuild <linux-kbuild@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Sam Ravnborg <sam@ravnborg.org>,
Ulf Magnusson <ulfalizer@gmail.com>,
Nicholas Piggin <npiggin@gmail.com>,
Emese Revfy <re.emese@gmail.com>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 21/30] stack-protector: test compiler capability in Kconfig and drop AUTO mode
Date: Sun, 15 Apr 2018 18:40:20 +0900 [thread overview]
Message-ID: <CAK7LNATM=7b_KReRZ8MqhiLPfP_itaxOW-17zHZpzSn_AOgThw@mail.gmail.com> (raw)
In-Reply-To: <CAGXu5jLt4xoxXTw83-npD4WmumPzSC9WnbOkkDoR=VYa5R4rYw@mail.gmail.com>
2018-04-14 1:41 GMT+09:00 Kees Cook <keescook@chromium.org>:
> On Thu, Apr 12, 2018 at 10:06 PM, Masahiro Yamada
> <yamada.masahiro@socionext.com> wrote:
>> +stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector
>> +stackp-flags-$(CONFIG_CC_STACKPROTECTOR) := -fstack-protector
>> +stackp-flags-$(CONFIG_CC_STACKPROTECTOR_STRONG) := -fstack-protector-strong
>> +
>> +KBUILD_CFLAGS += $(stackp-flags-y)
>
> So, technically, this works just fine. I wonder if it has an overly
> confusing result, in that the compiler under normal situations will
> see:
>
> gcc ... -fno-stack-protector -fstack-protector -fstack-protector-strong ...
Kees, you are wrong.
Look at my code closely.
I used := operator instead of +=.
$(stackp-flags-y) contains only one flag at most.
> How about something like this instead:
>
> ifdef CONFIG_CC_STACKPROTECTOR_STRONG
> KBUILD_CFLAGS += -fstack-protector-strong
> else
> ifdef CONFIG_CC_STACKPROTECTOR
> KBUILD_CFLAGS += -fstack-protector
> else
> KBUILD_CFLAGS += -fno-stack-protector
> endif
> endif
>
My code is much cleaner, and working fine.
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2018-04-15 9:41 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-13 5:06 [PATCH 00/30] kconfig: move compiler capability tests to Kconfig Masahiro Yamada
2018-04-13 5:06 ` [PATCH 01/30] gcc-plugins: fix build condition of SANCOV plugin Masahiro Yamada
2018-05-04 14:21 ` Masahiro Yamada
2018-05-04 16:21 ` Kees Cook
2018-05-05 1:35 ` Masahiro Yamada
2018-04-13 5:06 ` [PATCH 02/30] kbuild: remove kbuild cache Masahiro Yamada
2018-04-13 5:06 ` [PATCH 03/30] kbuild: remove CONFIG_CROSS_COMPILE support Masahiro Yamada
2018-04-13 5:06 ` [PATCH 04/30] kconfig: reference environment variables directly and remove 'option env=' Masahiro Yamada
2018-04-13 5:06 ` [PATCH 05/30] kconfig: remove string expansion in file_lookup() Masahiro Yamada
2018-04-13 5:06 ` [PATCH 06/30] kconfig: remove string expansion for mainmenu after yyparse() Masahiro Yamada
2018-04-13 5:06 ` [PATCH 07/30] kconfig: remove sym_expand_string_value() Masahiro Yamada
2018-04-13 5:06 ` [PATCH 08/30] kconfig: add built-in function support Masahiro Yamada
2018-04-15 7:57 ` Ulf Magnusson
2018-04-15 15:12 ` Masahiro Yamada
2018-04-13 5:06 ` [PATCH 09/30] kconfig: add 'shell' built-in function Masahiro Yamada
2018-04-13 5:06 ` [PATCH 10/30] kconfig: replace $(UNAME_RELEASE) with function call Masahiro Yamada
2018-04-13 5:06 ` [PATCH 11/30] kconfig: begin PARAM state only when seeing a command keyword Masahiro Yamada
2018-04-13 5:06 ` [PATCH 12/30] kconfig: support variable and user-defined function Masahiro Yamada
2018-04-13 5:06 ` [PATCH 13/30] kconfig: support simply expanded variable Masahiro Yamada
2018-04-13 5:06 ` [PATCH 14/30] kconfig: support append assignment operator Masahiro Yamada
2018-04-13 5:06 ` [PATCH 15/30] kconfig: expand lefthand side of assignment statement Masahiro Yamada
2018-04-13 5:06 ` [PATCH 16/30] kconfig: add 'info' and 'warning' built-in functions Masahiro Yamada
2018-04-13 5:06 ` [PATCH 17/30] Documentation: kconfig: document a new Kconfig macro language Masahiro Yamada
2018-04-14 23:33 ` Randy Dunlap
2018-04-17 15:05 ` Masahiro Yamada
2018-04-15 8:08 ` Ulf Magnusson
2018-04-17 15:07 ` Masahiro Yamada
2018-04-18 8:33 ` Ulf Magnusson
2018-04-13 5:06 ` [PATCH 18/30] kconfig: test: test text expansion Masahiro Yamada
2018-04-13 5:06 ` [PATCH 19/30] kconfig: show compiler version text in the top comment Masahiro Yamada
2018-04-13 5:06 ` [PATCH 20/30] kconfig: add basic helper macros to scripts/Kconfig.include Masahiro Yamada
2018-04-15 7:41 ` Ulf Magnusson
2018-04-15 15:02 ` Masahiro Yamada
2018-04-13 5:06 ` [PATCH 21/30] stack-protector: test compiler capability in Kconfig and drop AUTO mode Masahiro Yamada
2018-04-13 16:41 ` Kees Cook
2018-04-13 18:11 ` Linus Torvalds
2018-04-13 20:41 ` Kees Cook
2018-04-15 13:28 ` Masahiro Yamada
2018-04-15 16:04 ` Kees Cook
2018-04-15 9:40 ` Masahiro Yamada [this message]
2018-04-13 5:06 ` [PATCH 22/30] kconfig: add CC_IS_GCC and GCC_VERSION Masahiro Yamada
2018-04-13 5:06 ` [PATCH 23/30] kconfig: add CC_IS_CLANG and CLANG_VERSION Masahiro Yamada
2018-04-13 5:06 ` [PATCH 24/30] gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT Masahiro Yamada
2018-04-13 5:06 ` [PATCH 25/30] kcov: test compiler capability in Kconfig and correct dependency Masahiro Yamada
2018-04-13 5:06 ` [PATCH 26/30] gcc-plugins: move GCC version check for PowerPC to Kconfig Masahiro Yamada
2018-04-13 5:06 ` [PATCH 27/30] gcc-plugins: test plugin support in Kconfig and clean up Makefile Masahiro Yamada
2018-04-13 5:06 ` [PATCH 28/30] gcc-plugins: allow to enable GCC_PLUGINS for COMPILE_TEST Masahiro Yamada
2018-04-13 5:06 ` [PATCH 29/30] arm64: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig Masahiro Yamada
2018-04-13 5:06 ` [PATCH 30/30] kbuild: test dead code/data elimination support in Kconfig Masahiro Yamada
2018-04-13 5:17 ` [PATCH 00/30] kconfig: move compiler capability tests to Kconfig Masahiro Yamada
2018-04-13 5:52 ` Kees Cook
2018-04-13 12:21 ` Masahiro Yamada
2018-04-13 13:55 ` Masahiro Yamada
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