[linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 2785 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   2052923327794192c5d884623b5ee5fec1867bda
commit: d106ad47e292fde47fc09e16a2ddc13609ff2ad1 [5868/6773] mm-fix-phys_to_target_node-and-memory_add_physaddr_to_nid-exports-v4
config: powerpc64-randconfig-r026-20201118 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b2613fb2f0f53691dd0211895afbb9413457fca7)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc64 cross compiling tool for clang build
        # apt-get install binutils-powerpc64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=d106ad47e292fde47fc09e16a2ddc13609ff2ad1
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout d106ad47e292fde47fc09e16a2ddc13609ff2ad1
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping' [-Wmissing-prototypes]
   int __weak create_section_mapping(unsigned long start, unsigned long end,
              ^
   arch/powerpc/mm/mem.c:91:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int __weak create_section_mapping(unsigned long start, unsigned long end,
   ^
   static 
   1 warning generated.

vim +/create_section_mapping +91 arch/powerpc/mm/mem.c

bc02af93dd2bbdd Yasunori Goto          2006-06-27  90  
4e00c5affdd4b04 Logan Gunthorpe        2020-04-10 @91  int __weak create_section_mapping(unsigned long start, unsigned long end,
4e00c5affdd4b04 Logan Gunthorpe        2020-04-10  92  				  int nid, pgprot_t prot)
fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05  93  {
fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05  94  	return -ENODEV;
fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05  95  }
fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05  96  

:::::: The code at line 91 was first introduced by commit
:::::: 4e00c5affdd4b04e6392001716333971932f3d0c powerpc/mm: thread pgprot_t through create_section_mapping()

:::::: TO: Logan Gunthorpe <logang@deltatee.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 32306 bytes --]

Re: [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[Dan Williams]

On Wed, Nov 18, 2020 at 4:27 AM kernel test robot <lkp@intel.com> wrote:
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   2052923327794192c5d884623b5ee5fec1867bda
> commit: d106ad47e292fde47fc09e16a2ddc13609ff2ad1 [5868/6773] mm-fix-phys_to_target_node-and-memory_add_physaddr_to_nid-exports-v4
> config: powerpc64-randconfig-r026-20201118 (attached as .config)
> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b2613fb2f0f53691dd0211895afbb9413457fca7)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install powerpc64 cross compiling tool for clang build
>         # apt-get install binutils-powerpc64-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=d106ad47e292fde47fc09e16a2ddc13609ff2ad1
>         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>         git fetch --no-tags linux-next master
>         git checkout d106ad47e292fde47fc09e16a2ddc13609ff2ad1
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64

I get:

Makefile:597: arch/powerpc64/Makefile: No such file or directory
make[1]: *** No rule to make target 'arch/powerpc64/Makefile'.  Stop.
make: *** [Makefile:712: include/config/auto.conf.cmd] Error 2

...changing it to ARCH=powerpc I get:

Assembler messages:
Fatal error: invalid listing option `3'
clang: error: assembler command failed with exit code 1 (use -v to see
invocation)
make[1]: *** [scripts/Makefile.build:283: scripts/mod/empty.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1199: prepare0] Error 2

This is on a Fedora 31 host.

>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> >> arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping' [-Wmissing-prototypes]
>    int __weak create_section_mapping(unsigned long start, unsigned long end,
>               ^
>    arch/powerpc/mm/mem.c:91:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>    int __weak create_section_mapping(unsigned long start, unsigned long end,
>    ^
>    static
>    1 warning generated.

I do not see these errors with gcc.

I feel like clang errors should be flagged / de-emphasized when the
same error does not appear on gcc.

Re: [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[Nick Desaulniers]

On Wed, Nov 18, 2020 at 11:22 AM Dan Williams <dan.j.williams@intel.com> wrote:
>
> On Wed, Nov 18, 2020 at 4:27 AM kernel test robot <lkp@intel.com> wrote:
> >
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> > head:   2052923327794192c5d884623b5ee5fec1867bda
> > commit: d106ad47e292fde47fc09e16a2ddc13609ff2ad1 [5868/6773] mm-fix-phys_to_target_node-and-memory_add_physaddr_to_nid-exports-v4
> > config: powerpc64-randconfig-r026-20201118 (attached as .config)

^ randconfig

> > compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b2613fb2f0f53691dd0211895afbb9413457fca7)
> > reproduce (this is a W=1 build):

^ W=1

> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # install powerpc64 cross compiling tool for clang build
> >         # apt-get install binutils-powerpc64-linux-gnu
> >         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=d106ad47e292fde47fc09e16a2ddc13609ff2ad1
> >         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> >         git fetch --no-tags linux-next master
> >         git checkout d106ad47e292fde47fc09e16a2ddc13609ff2ad1
> >         # save the attached .config to linux build tree
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64
>
> I get:
>
> Makefile:597: arch/powerpc64/Makefile: No such file or directory
> make[1]: *** No rule to make target 'arch/powerpc64/Makefile'.  Stop.
> make: *** [Makefile:712: include/config/auto.conf.cmd] Error 2
>
> ...changing it to ARCH=powerpc I get:
>
> Assembler messages:
> Fatal error: invalid listing option `3'
> clang: error: assembler command failed with exit code 1 (use -v to see
> invocation)
> make[1]: *** [scripts/Makefile.build:283: scripts/mod/empty.o] Error 1
> make[1]: *** Waiting for unfinished jobs....
> make: *** [Makefile:1199: prepare0] Error 2
>
> This is on a Fedora 31 host.
>
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All warnings (new ones prefixed by >>):
> >
> > >> arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping' [-Wmissing-prototypes]
> >    int __weak create_section_mapping(unsigned long start, unsigned long end,
> >               ^
> >    arch/powerpc/mm/mem.c:91:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
> >    int __weak create_section_mapping(unsigned long start, unsigned long end,
> >    ^
> >    static
> >    1 warning generated.
>
> I do not see these errors with gcc.
>
> I feel like clang errors should be flagged / de-emphasized when the
> same error does not appear on gcc.

Note this is a W=1 build. For this warning, you either need to mark
functions as having static linkage, or provide a prototype in a header
so that callers know the correct function signature.
-- 
Thanks,
~Nick Desaulniers

Re: [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[Randy Dunlap]

On 11/18/20 11:52 AM, Nick Desaulniers wrote:
> On Wed, Nov 18, 2020 at 11:22 AM Dan Williams <dan.j.williams@intel.com> wrote:
>>
>> On Wed, Nov 18, 2020 at 4:27 AM kernel test robot <lkp@intel.com> wrote:
>>>
>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>>> head:   2052923327794192c5d884623b5ee5fec1867bda
>>> commit: d106ad47e292fde47fc09e16a2ddc13609ff2ad1 [5868/6773] mm-fix-phys_to_target_node-and-memory_add_physaddr_to_nid-exports-v4
>>> config: powerpc64-randconfig-r026-20201118 (attached as .config)
> 
> ^ randconfig
> 
>>> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b2613fb2f0f53691dd0211895afbb9413457fca7)
>>> reproduce (this is a W=1 build):
> 
> ^ W=1
> 
>>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>>         chmod +x ~/bin/make.cross
>>>         # install powerpc64 cross compiling tool for clang build
>>>         # apt-get install binutils-powerpc64-linux-gnu
>>>         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=d106ad47e292fde47fc09e16a2ddc13609ff2ad1
>>>         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>>>         git fetch --no-tags linux-next master
>>>         git checkout d106ad47e292fde47fc09e16a2ddc13609ff2ad1
>>>         # save the attached .config to linux build tree
>>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64
>>
>> I get:
>>
>> Makefile:597: arch/powerpc64/Makefile: No such file or directory
>> make[1]: *** No rule to make target 'arch/powerpc64/Makefile'.  Stop.
>> make: *** [Makefile:712: include/config/auto.conf.cmd] Error 2
>>
>> ...changing it to ARCH=powerpc I get:
>>
>> Assembler messages:
>> Fatal error: invalid listing option `3'
>> clang: error: assembler command failed with exit code 1 (use -v to see
>> invocation)
>> make[1]: *** [scripts/Makefile.build:283: scripts/mod/empty.o] Error 1
>> make[1]: *** Waiting for unfinished jobs....
>> make: *** [Makefile:1199: prepare0] Error 2
>>
>> This is on a Fedora 31 host.
>>
>>>
>>> If you fix the issue, kindly add following tag as appropriate
>>> Reported-by: kernel test robot <lkp@intel.com>
>>>
>>> All warnings (new ones prefixed by >>):
>>>
>>>>> arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping' [-Wmissing-prototypes]
>>>    int __weak create_section_mapping(unsigned long start, unsigned long end,
>>>               ^
>>>    arch/powerpc/mm/mem.c:91:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>>>    int __weak create_section_mapping(unsigned long start, unsigned long end,
>>>    ^
>>>    static
>>>    1 warning generated.
>>
>> I do not see these errors with gcc.
>>
>> I feel like clang errors should be flagged / de-emphasized when the
>> same error does not appear on gcc.
> 
> Note this is a W=1 build. For this warning, you either need to mark
> functions as having static linkage, or provide a prototype in a header
> so that callers know the correct function signature.

Yes, so with gcc, that gave me something like 109 missing prototype
warnings -- including one for 'create_section_mapping'.

-- 
~Randy

Re: [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[Dan Williams]

On Wed, Nov 18, 2020 at 1:20 PM Randy Dunlap <rdunlap@infradead.org> wrote:
[..]
> Yes, so with gcc, that gave me something like 109 missing prototype
> warnings -- including one for 'create_section_mapping'.

You see those with this [1] applied? I don't see those warnings
anymore with gcc-10.2.0 and that patch.

[1]: http://lore.kernel.org/r/160558386174.2948926.2740149041249041764.stgit@dwillia2-desk3.amr.corp.intel.com

Re: [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[Nick Desaulniers]

On Wed, Nov 18, 2020 at 11:22 AM Dan Williams <dan.j.williams@intel.com> wrote:
>
> I do not see these errors with gcc.
>
> I feel like clang errors should be flagged / de-emphasized when the
> same error does not appear on gcc.

Also, note that Clang has warnings GCC does not, and vice versa (I
imagine a Venn Diagram).  I give you the benefit of the doubt to mean
"warnings that both compilers support, but only one is emitting for
whatever reason" which is fair; though warnings unique to one compiler
can be a competitive advantage.
-- 
Thanks,
~Nick Desaulniers

Re: [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

[Randy Dunlap]

On 11/18/20 1:38 PM, Dan Williams wrote:
> On Wed, Nov 18, 2020 at 1:20 PM Randy Dunlap <rdunlap@infradead.org> wrote:
> [..]
>> Yes, so with gcc, that gave me something like 109 missing prototype
>> warnings -- including one for 'create_section_mapping'.
> 
> You see those with this [1] applied? I don't see those warnings
> anymore with gcc-10.2.0 and that patch.
> 
> [1]: http://lore.kernel.org/r/160558386174.2948926.2740149041249041764.stgit@dwillia2-desk3.amr.corp.intel.com
> 

No, I was testing today's linux-next (20201118).
and gcc 7.5.0.

After applying that patch, that 1 out of 111 -Wmissing-prototype warnings
is gone.  :)

Thanks.