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From: Michal Marek <mmarek@suse.cz>
To: Stephen Rothwell <sfr@canb.auug.org.au>,
	Nicholas Piggin <npiggin@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
	Al Viro <viro@zeniv.linux.org.uk>,
	PowerPC <linuxppc-dev@lists.ozlabs.org>
Subject: Re: linux-next: build warnings after merge of the kbuild tree
Date: Fri, 19 Aug 2016 10:37:00 +0200	[thread overview]
Message-ID: <5babe9ef-0e3d-6975-9ba4-9a29a700b24d@suse.cz> (raw)
In-Reply-To: <20160819150914.36106b5b@canb.auug.org.au>

On 2016-08-19 07:09, Stephen Rothwell wrote:
> Hi Nick,
> 
> On Fri, 19 Aug 2016 13:38:54 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>>
>> On Thu, 18 Aug 2016 11:09:48 +1000 Nicholas Piggin <npiggin@gmail.com> wrote:
>>>
>>> On Wed, 17 Aug 2016 14:59:59 +0200
>>> Michal Marek <mmarek@suse.cz> wrote:
>>>   
>>>> On 2016-08-17 03:44, Stephen Rothwell wrote:    
>>>>>
>>>>> After merging the kbuild tree, today's linux-next build (powerpc
>>>>> ppc64_defconfig) produced these warnings:
>>>>>
>>>>> WARNING: 25 bad relocations
>>>>> c000000000cf2570 R_PPC64_ADDR64    __crc___arch_hweight16      
>>>> [...]    
>>>>> Introduced by commit
>>>>>
>>>>>   9445aa1a3062 ("ppc: move exports to definitions")
>>>>>
>>>>> I have reverted that commit for today.
>>>>>
>>>>> [cc-ing the ppc guys for clues - also involved is commit
>>>>>
>>>>>   22823ab419d8 ("EXPORT_SYMBOL() for asm")
>>>>> ]      
>>>>
>>>> FWIW, I see these warnings as well. Any help from ppc developers is
>>>> appreciated - should the R_PPC64_ADDR64 be whitelisted for exported asm
>>>> symbols (their CRCs actually)?    
>>>
>>> The dangling relocation is a side effect of linker unable to resolve the
>>> reference to the undefined weak symbols. So the real question is, why has
>>> genksyms not overridden these symbols with their CRC values?
>>>
>>> This may not even be powerpc specific, but  I'll poke at it a bit more
>>> when I get a chance.  
>>
>> Not sure if this is relevant, but with the commit reverted, the
>> __crc___... symbols are absolute.
>>
>> 00000000f55b3b3d A __crc___arch_hweight16
> 
> Ignore that :-)
> 
> I just had a look at a x86_64 allmodconfig result and it looks like the
> weak symbols are not resolved their either ...
> 
> I may be missing something, but genksyms generates the crc's off the
> preprocessed C source code and we don't have any for the asm files ...

Of course you are right. Which means that we are losing type information
for these exports for CONFIG_MODVERSIONS purposes. I guess it's
acceptable, since the asm functions are pretty basic and their
signatures do not change.

Michal

  parent reply	other threads:[~2016-08-19  8:37 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-17  1:44 linux-next: build warnings after merge of the kbuild tree Stephen Rothwell
2016-08-17 12:59 ` Michal Marek
2016-08-18  1:09   ` Nicholas Piggin
2016-08-19  3:38     ` Stephen Rothwell
2016-08-19  5:09       ` Stephen Rothwell
2016-08-19  5:32         ` Nicholas Piggin
2016-08-19  8:37         ` Michal Marek [this message]
2016-08-19 10:44           ` Nicholas Piggin
2016-08-22 10:47             ` Nicholas Piggin
2016-08-26  3:58               ` Nicholas Piggin
2016-08-26  6:21                 ` Nicholas Mc Guire
  -- strict thread matches above, loose matches on Subject: below --
2022-06-01 23:28 Stephen Rothwell
2019-09-04  0:13 Stephen Rothwell
2019-09-04  1:00 ` Masahiro Yamada
2019-09-04  6:22   ` Masahiro Yamada
2019-09-04 12:33     ` Stephen Rothwell
2019-09-04 12:32   ` Stephen Rothwell
2018-05-30 22:40 Stephen Rothwell
2018-05-31  1:12 ` Masahiro Yamada
2018-05-31  1:26   ` Kees Cook
2018-05-31  3:53     ` Kees Cook
2018-06-01  1:56       ` Masahiro Yamada
2018-06-01  4:01         ` Kees Cook
2018-06-02 20:39           ` Arnd Bergmann
2018-06-04  8:39             ` Arnd Bergmann
2017-07-19  0:05 Stephen Rothwell
2016-06-09  2:22 Stephen Rothwell
2016-06-09  2:56 ` Kees Cook
2016-06-09  4:05   ` Stephen Rothwell
2016-06-09 10:57     ` Michal Marek
2016-06-09 17:37       ` Emese Revfy
2016-06-09 17:58         ` Kees Cook
2016-06-09 11:10     ` Michael Ellerman
2016-06-09 17:42 ` Emese Revfy

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