Re: [PATCH v2 3/5] kbuild: Use relative path for $(objtree)

From: Michal Marek <mmarek@suse.cz>
To: Randy Dunlap <rdunlap@infradead.org>,
	Richard Weinberger <richard.weinberger@gmail.com>
Cc: linux-kbuild@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [PATCH v2 3/5] kbuild: Use relative path for $(objtree)
Date: Tue, 10 Jun 2014 00:14:36 +0200	[thread overview]
Message-ID: <539631CC.9040002@suse.cz> (raw)
In-Reply-To: <539625D1.2090905@infradead.org>

Dne 9.6.2014 23:23, Randy Dunlap napsal(a):
> On 06/05/14 08:56, Michal Marek wrote:
>> On Wed, Jun 04, 2014 at 03:12:33PM +0200, Michal Marek wrote:
>>> On 2014-06-04 11:43, Michal Marek wrote:
>>>> On 2014-06-04 11:03, Richard Weinberger wrote:
>>>>> To reproduce run:
>>>>> make defconfig ARCH=um O=/mnt/o && make linux ARCH=um O=/mnt/
>>>>>
>>>>> If there is anything in UML which needs fixing, please tell. :-)
>>>>
>>>> I'll have a look, thanks for the report.
>>>
>>> Findings so far: For some reason, syscalls_32.h is generated in the
>>> source tree (which is wrong) and syscalls_64.h is not generated at all.
>>> Looking further.
>>
>> Can you try the below patch? The same pattern is used in the rules for
>> tools/ and tools/% in the main Makefile, need to look into that as well.
>> But UML should work now.
>>
>> Michal
>>
>> From d4bc590f8716f7dde6b7bca319097ac30a8cb0b4 Mon Sep 17 00:00:00 2001
>> From: Michal Marek <mmarek@suse.cz>
>> Date: Thu, 5 Jun 2014 17:44:44 +0200
>> Subject: [PATCH] um: Fix for relative objtree when generating x86 headers
>>
>> In an O= build, rely on the generated Makefile to call the main Makefile
>> properly. When building in the source tree, we do not need to specify
>> the -C and O= either. This fixes the problem when $(objtree) is a
>> relative path and the -C changes the directory.
>>
>> Reported-by: Richard Weinberger <richard.weinberger@gmail.com>
>> Signed-off-by: Michal Marek <mmarek@suse.cz>
>> ---
>>  arch/um/Makefile | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/arch/um/Makefile b/arch/um/Makefile
>> index 36e658a..e4b1a96 100644
>> --- a/arch/um/Makefile
>> +++ b/arch/um/Makefile
>> @@ -111,8 +111,7 @@ endef
>>  KBUILD_KCONFIG := $(HOST_DIR)/um/Kconfig
>>  
>>  archheaders:
>> -	$(Q)$(MAKE) -C '$(srctree)' KBUILD_SRC= \
>> -		ARCH=$(HEADER_ARCH) O='$(objtree)' archheaders
>> +	$(Q)$(MAKE) KBUILD_SRC= ARCH=$(HEADER_ARCH) archheaders
>>  
>>  archprepare: include/generated/user_constants.h
>>  
>>
> 
> I still get this build error when building uml for i386:
> 
>   CC      arch/x86/um/user-offsets.s
> ../arch/x86/um/user-offsets.c:14:29: fatal error: asm/syscalls_32.h: No such file or directory
> compilation terminated.
> make[2]: *** [arch/x86/um/user-offsets.s] Error 1

Thanks for testing the patch. I cannot reproduce it though:

  make ARCH=um SUBARCH=i386 O=/dev/shm/li defconfig
  make ARCH=um SUBARCH=i386 O=/dev/shm/li

works fine (at least it gets to the point when it starts compiling the
actual kernel source). This is the previous kbuild/kbuild branch (commit
9da0763) with the above fix applied.

Also, you pointed out i386 -- Does it mean that the fix worked for you
on x86_64?

Thanks,
Michal