From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Ulf Magnusson <ulfalizer@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>,
Randy Dunlap <rdunlap@infradead.org>,
Michal Marek <michal.lkml@markovi.net>,
Peter Oberparleiter <oberpar@linux.vnet.ibm.com>,
kernel-hardening@lists.openwall.com,
Jonathan Corbet <corbet@lwn.net>,
sparclinux@vger.kernel.org,
Linux-sh list <linux-sh@vger.kernel.org>, X86 ML <x86@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Rich Felker <dalias@libc.org>, Jeff Dike <jdike@addtoit.com>,
"H. Peter Anvin" <hpa@zytor.com>,
user-mode-linux-devel@lists.sourceforge.net,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@samba.org>,
user-mode-linux-user@lists.sourceforge.net,
Ingo Molnar <mingo@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Michael Ellerman <mpe@ellerman.id.au>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Richard Weinberger <richard@nod.at>,
Emese Revfy <re.emese@gmail.com>
Subject: Re: [PATCH 00/23] kconfig: move compiler capability tests to Kconfig
Date: Wed, 21 Feb 2018 16:38:25 +0900 [thread overview]
Message-ID: <CAK7LNAQH0WD3A3T97gce0xmZpMy0zWxTO2StfNWaDbiqjQg8gg@mail.gmail.com> (raw)
In-Reply-To: <CAFkk2KT1krKuDkWt0eHcasfC61fTVQNf-1kqw7icLP9OYGYkXQ@mail.gmail.com>
2018-02-20 0:18 GMT+09:00 Ulf Magnusson <ulfalizer@gmail.com>:
>>
>> I'm not happy that we in one context can reference CONFIG variables
>> directly, but inside the $(call ...) and $(shell ...) needs the $ prefix.
>> But I could not come up with something un-ambigious where this could be avoided.
>
> I think we should be careful about allowing references to config
> symbols. It mixes up the parsing and evaluation phases, since $() is
> expanded during parsing (which I consider a feature and think is
> needed to retain sanity).
>
> Patch 06/23 removes the last existing instance of symbol references in
> strings by getting rid of 'option env'. That's an improvement to me.
> We shouldn't add it back.
This is really important design decision,
so I'd like to hear a little more from experts.
For example, x86 allows users to choose sub-arch, either 'i386' or 'x86_64'.
https://github.com/torvalds/linux/blob/v4.16-rc2/arch/x86/Kconfig#L4
If the user toggles CONFIG_64BIT,
the bi-arch compiler will work in a slightly different mode
(at least, back-end parts)
So, my question is, is there a case,
$(cc-option, -m32 -foo) is y, but
$(cc-option, -m64 -foo) is n ?
(or vice versa)
If the answer is yes, $(cc-option -foo) would have to be re-calculated
every time CONFIG_64BIT is toggled.
This is what I'd like to avoid, though.
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2018-02-21 7:38 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-16 18:38 [PATCH 00/23] kconfig: move compiler capability tests to Kconfig Masahiro Yamada
2018-02-16 18:38 ` [PATCH 01/23] kbuild: remove kbuild cache Masahiro Yamada
2018-02-16 18:38 ` [PATCH 02/23] kbuild: remove CONFIG_CROSS_COMPILE support Masahiro Yamada
2018-02-16 18:38 ` [PATCH 03/23] kconfig: add xstrdup() helper Masahiro Yamada
2018-03-01 15:02 ` Masahiro Yamada
2018-02-16 18:38 ` [PATCH 04/23] kconfig: set SYMBOL_AUTO to the symbol marked with defconfig_list Masahiro Yamada
2018-03-01 15:05 ` Masahiro Yamada
2018-03-01 17:11 ` Ulf Magnusson
2018-02-16 18:38 ` [PATCH 05/23] kconfig: move and rename sym_expand_string_value() Masahiro Yamada
2018-02-16 18:38 ` [PATCH 06/23] kconfig: reference environments directly and remove 'option env=' syntax Masahiro Yamada
2018-02-18 11:15 ` Ulf Magnusson
2018-02-16 18:38 ` [PATCH 07/23] kconfig: add function support and implement 'shell' function Masahiro Yamada
2018-02-17 16:16 ` Ulf Magnusson
2018-02-19 15:57 ` Masahiro Yamada
2018-02-19 17:50 ` Ulf Magnusson
2018-02-19 20:06 ` Ulf Magnusson
2018-02-19 22:06 ` Ulf Magnusson
2018-02-16 18:38 ` [PATCH 08/23] kconfig: add 'macro' keyword to support user-defined function Masahiro Yamada
2018-02-16 19:49 ` Nicolas Pitre
2018-02-16 23:51 ` Ulf Magnusson
2018-02-17 2:30 ` Nicolas Pitre
2018-02-17 4:29 ` Ulf Magnusson
2018-02-17 4:44 ` Nicolas Pitre
2018-02-17 6:06 ` Ulf Magnusson
2018-02-16 18:38 ` [PATCH 09/23] kconfig: add 'cc-option' macro Masahiro Yamada
2018-02-16 18:38 ` [PATCH 10/23] stack-protector: test compiler capability in Kconfig and drop AUTO mode Masahiro Yamada
2018-02-21 4:39 ` Masahiro Yamada
2018-02-16 18:38 ` [PATCH 11/23] kconfig: add 'shell-stdout' function Masahiro Yamada
2018-02-16 19:17 ` Linus Torvalds
2018-02-19 4:48 ` Ulf Magnusson
2018-02-19 17:44 ` Linus Torvalds
2018-02-19 18:01 ` Linus Torvalds
2018-02-19 18:54 ` Ulf Magnusson
2018-02-21 4:59 ` Masahiro Yamada
2018-02-21 16:41 ` Ulf Magnusson
2018-02-21 17:01 ` Linus Torvalds
2018-02-16 18:38 ` [PATCH 12/23] kconfig: replace $UNAME_RELEASE with function call Masahiro Yamada
2018-02-16 18:38 ` [PATCH 13/23] kconfig: expand environments/functions in (main)menu, comment, prompt Masahiro Yamada
2018-02-16 18:38 ` [PATCH 14/23] kconfig: show compiler version text in the top comment Masahiro Yamada
2018-02-16 18:38 ` [PATCH 15/23] kconfig: add CC_IS_GCC and GCC_VERSION Masahiro Yamada
2018-02-16 18:38 ` [PATCH 16/23] kbuild: add clang-version.sh Masahiro Yamada
2018-02-16 18:38 ` [PATCH 17/23] kconfig: add CC_IS_CLANG and CLANG_VERSION Masahiro Yamada
2018-02-16 18:38 ` [PATCH 18/23] gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT Masahiro Yamada
2018-02-16 18:38 ` [PATCH 19/23] kcov: imply GCC_PLUGINS and GCC_PLUGIN_SANCOV instead of select'ing them Masahiro Yamada
2018-02-16 18:38 ` [PATCH 20/23] gcc-plugins: always build plugins with C++ Masahiro Yamada
2018-02-22 18:45 ` Emese Revfy
2018-02-23 12:37 ` Masahiro Yamada
2018-02-16 18:38 ` [PATCH 21/23] gcc-plugins: move GCC version check for PowerPC to Kconfig Masahiro Yamada
2018-02-22 5:04 ` Andrew Donnellan
2018-02-16 18:38 ` [PATCH 22/23] gcc-plugins: test GCC plugin support in Kconfig Masahiro Yamada
2018-02-16 18:38 ` [PATCH 23/23] gcc-plugins: enable GCC_PLUGINS for COMPILE_TEST Masahiro Yamada
2018-02-18 22:13 ` [PATCH 00/23] kconfig: move compiler capability tests to Kconfig Sam Ravnborg
2018-02-19 15:18 ` Ulf Magnusson
2018-02-21 7:38 ` Masahiro Yamada [this message]
2018-02-21 9:56 ` Arnd Bergmann
2018-02-21 10:20 ` Masahiro Yamada
2018-02-21 10:52 ` Arnd Bergmann
2018-02-21 12:57 ` Masahiro Yamada
2018-02-21 16:03 ` Arnd Bergmann
2018-02-21 21:39 ` Ulf Magnusson
2018-03-02 5:50 ` Masahiro Yamada
2018-03-02 9:03 ` Ulf Magnusson
2018-03-02 9:12 ` Ulf Magnusson
2018-02-22 3:22 ` Michael Ellerman
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