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From: Michael Ellerman <mpe@ellerman.id.au>
To: Masahiro Yamada <yamada.masahiro@socionext.com>,
	Arnd Bergmann <arnd@arndb.de>
Cc: Rich Felker <dalias@libc.org>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	X86 ML <x86@kernel.org>, Paul Mackerras <paulus@samba.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	sparclinux <sparclinux@vger.kernel.org>,
	Sam Ravnborg <sam@ravnborg.org>,
	Yoshinori Sato <ysato@users.sourceforge.jp>,
	Jonathan Corbet <corbet@lwn.net>,
	Richard Weinberger <richard@nod.at>,
	Linux-sh list <linux-sh@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@redhat.com>, Emese Revfy <re.emese@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	uml-devel <user-mode-linux-devel@lists.sourceforge.net>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Peter Oberparleiter <oberpar@linux.vnet.ibm.com>,
	Jeff Dike <jdike@addtoit.com>,
	user-mode-linux-user@lists.sourceforge.net,
	Thomas Gleixner <tglx@linutronix.de>,
	Michal Marek <michal.lkml@markovi.net>,
	Ulf Magnusson <ulfalizer@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH 00/23] kconfig: move compiler capability tests to Kconfig
Date: Thu, 22 Feb 2018 14:22:02 +1100	[thread overview]
Message-ID: <87efldr9np.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <CAK7LNAR3OMh9Q9ZfaBq=FpSJ-+DT5-RH_20ohV-iu34pX9hFKw@mail.gmail.com>

Masahiro Yamada <yamada.masahiro@socionext.com> writes:
>
<snip>
>
> (Case 3)
> Compiler flag -foo is sensitive to endian-ness.
>
>
> config CC_NEEDS_BIG_ENDIAN
>           def_bool $(cc-option -mbig-endian) && CPU_BIG_ENDIAN
>
> config CC_NEEDS_LITTLE_ENDIAN
>           def_bool $(cc-option -mlittle-endian) && CPU_LITTLE_ENDIAN
>
> config CC_HAS_FOO
>          bool
>          default $(cc-option -mbig-endian -foo) if CC_NEEDS_BIG_ENDIAN
>          default $(cc-option -mlittle-endian -foo) if CC_NEEDS_LITTLE_ENDIAN
>          default $(cc-option -foo)

We may do something like this on powerpc, where we have 32/64-bit and
big/little endian (on 64-bit) and then some ABI options that we
set/unset depending on endian.

The above looks like it could work though.

cheers


      parent reply	other threads:[~2018-02-22  3:22 UTC|newest]

Thread overview: 16+ 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 06/23] kconfig: reference environments directly and remove 'option env=' syntax Masahiro Yamada
2018-02-18 11:15   ` Ulf Magnusson
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
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 [this message]

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