From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226g79r3QOU2qIg/ayH9sotfWJtpBDpQV29hxoRADtBYfZxugnOc83Hv+6/Ww3If/jA1rlx2 ARC-Seal: i=1; a=rsa-sha256; t=1518512443; cv=none; d=google.com; s=arc-20160816; b=s7kvS9K3F3WDvVDdKwH1P0oqd5B+diIAX4CfXy6Km2WE9vhHrWWa1W1vNY53fqR2aC WUI3oN9illSkeJ/N9UCcFeYl/FuqnQI7PCUTsr1AdRHT9uKFFAPgvyehQdjgp4cOncvS gasj6bxUm9v651/gzOOAHKAQbhiz+2OPXHAUjCrHsYPDlWVDIszbrXuGVwiQAXS914oS gZa2yC89NXTXYLVHFgfm+fZphJlFTu5hj4duwBTq5HzpR66FtN3xOjIa8kkEsrDMLchS sXbtRF8w423acxX/HrYDpqjf3OZVSvb7RHIv4axYzfsrYqiDUTfRc8eWZOgGOMwb9GtR llYA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:references:in-reply-to :mime-version:dkim-signature:dkim-filter:arc-authentication-results; bh=OoHN3L+EgMi3QdRVCikhsLANjFHuDxATT8s2PGOuNn0=; b=cWfMl6PC6B8hnIQ1a5MerUGiNDNZHlUUHI6+K84Ji/6NRK15IuCIrPOu55C2g+1ffr Ef7fquaLK6l5qmxlpBAdYLvoFBZzk+HEjH3XgPGzpQD14zMDDiLIz7yAEPbJg4NOjGJn y9fnIXEWD+nVEcEbuT2s5fXzwbDhJensEeyhDO01tSP5twSWlWa1BMUEwYxxcGBR1WmP 0IWe0jKYtkOQKbY/KEiJjy59Nf356Ty1i8JlCRrMpgZqDJNxsKYmc6fu+gjGf7Uy6F5q idA7pHHI+KVdwVqazYxAP9ikeAZ+2p3gQoAL5LI3XYOz99U8nTx6udmS+fHfncJIS2B6 tWBA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@nifty.com header.s=dec2015msa header.b=QH7LZWwI; spf=softfail (google.com: domain of transitioning yamada.masahiro@socionext.com does not designate 210.131.2.83 as permitted sender) smtp.mailfrom=yamada.masahiro@socionext.com Authentication-Results: mx.google.com; dkim=pass header.i=@nifty.com header.s=dec2015msa header.b=QH7LZWwI; spf=softfail (google.com: domain of transitioning yamada.masahiro@socionext.com does not designate 210.131.2.83 as permitted sender) smtp.mailfrom=yamada.masahiro@socionext.com DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-04.nifty.com w1D906tR012229 X-Nifty-SrcIP: [209.85.213.51] MIME-Version: 1.0 In-Reply-To: References: <20180210054843.z3g7wvcmlccvww3h@huvuddator> <20180210074924.3nhxsza5zdbaahxx@huvuddator> <20180210080556.mycqsjhxbaguwhay@huvuddator> <20180210085519.737ckf4bcl57h4g2@huvuddator> <20180211103432.pf2ot6nd7nbhdhsy@huvuddator> <49c196ec-891d-2030-bd6c-7222feb22059@infradead.org> From: Masahiro Yamada Date: Tue, 13 Feb 2018 17:59:25 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH 4/7] kconfig: support new special property shell= To: Arnd Bergmann Cc: Randy Dunlap , Kees Cook , Ulf Magnusson , Linus Torvalds , Linux Kbuild mailing list , Greg Kroah-Hartman , Andrew Morton , Nicolas Pitre , "Luis R . Rodriguez" , Sam Ravnborg , Michal Marek , Martin Schwidefsky , Pavel Machek , linux-s390 , Jiri Kosina , Linux Kernel Mailing List , Tejun Heo , Ingo Molnar , "Van De Ven, Arjan" Content-Type: text/plain; charset="UTF-8" X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591850368607646970?= X-GMAIL-MSGID: =?utf-8?q?1592275703402855740?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 2018-02-13 17:35 GMT+09:00 Arnd Bergmann : > On Tue, Feb 13, 2018 at 2:53 AM, Randy Dunlap wrote: >> On 02/12/2018 05:41 PM, Masahiro Yamada wrote: >>> 2018-02-13 8:48 GMT+09:00 Randy Dunlap : >>>> On 02/12/2018 07:24 AM, Kees Cook wrote: >>>>> On Mon, Feb 12, 2018 at 6:39 AM, Masahiro Yamada >>>>> wrote: >>>> >>>>>>> (And in thinking about this, does Kconfig know the true $CC in use? >>>>>>> i.e. the configured cross compiler, etc?) >>>>>> >>>>>> I was thinking of removing CONFIG_CROSS_COMPILE. >>>>>> >>>>>> A user can dynamically change CROSS_COMPILE from >>>>>> "make menuconfig". >>>>> >>>>> Most builds I've seen implement cross compilers as an environment >>>>> variable during all "make" invocations. >>>> >>>> I agree. I think you would break a bunch of build bots if you remove that. >>> >>> >>> For clarification, I suggested to remove CONFIG_CROSS_COMPILE. >>> >>> The following code: >>> https://github.com/torvalds/linux/blob/v4.16-rc1/Makefile#L315 >>> https://github.com/torvalds/linux/blob/v4.16-rc1/init/Kconfig#L58 >>> >>> I hope build bots are not using this. >>> >>> >>> Passing CROSS_COMPILE via the command line, environment >>> is still supported. >> >> OK, I misunderstood. That one can go away IMO. > > Removing it will break the workflow for some people in a minor way > though. Could we have the top-level Makefile try to detect the > CROSS_COMPILE? Instead of just using CC=gcc as the default, > we could check for ${ARCH}!=`uname -m` and then see if $PATH > contains a ${ARCH}-linux-gcc, ${ARCH}-elf-gcc or ${ARCH}-gcc. > > it will need slightly more complexity to deal with architectures > that have different identifiers in linux and gcc, but I think it would > be a nice feature anyway. > > Arnd Some architectures such as m68k, mips, etc. do this in their arch/*/Makefile by using $(call cc-cross-prefix, ...) But, currently we do not do this globally. It would be possible to do it, but it does not mean backward-compatible with CONFIG_CROSS_COMPILE. -- Best Regards Masahiro Yamada