Re: [PATCH next resend 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.

Re: [PATCH next resend 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.

[kernel test robot]

Hi David,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master]
[cannot apply to next-20230725]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Laight/minmax-Allow-min-max-clamp-if-the-arguments-have-the-same-signedness/20230725-204940
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/a09512c8526b46759669d0b879144563%40AcuMS.aculab.com
patch subject: [PATCH next resend 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.
config: mips-randconfig-r016-20230725 (https://download.01.org/0day-ci/archive/20230726/202307260256.nzImScXA-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230726/202307260256.nzImScXA-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202307260256.nzImScXA-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/irqchip/irq-mips-cpu.c:288:1: error: call to undeclared function '__typecheck'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
         | ^
   include/linux/irqchip.h:37:38: note: expanded from macro 'IRQCHIP_DECLARE'
      37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
         |                                             ^
   include/linux/irqchip.h:24:3: note: expanded from macro 'typecheck_irq_init_cb'
      24 |         (__typecheck(typecheck_irq_init_cb, &fn) ? fn : fn)
         |          ^
>> drivers/irqchip/irq-mips-cpu.c:288:1: error: initializer element is not a compile-time constant
     288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
         | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/irqchip.h:37:2: note: expanded from macro 'IRQCHIP_DECLARE'
      37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/of.h:1493:3: note: expanded from macro 'OF_DECLARE_2'
    1493 |                 _OF_DECLARE(table, name, compat, fn, of_init_fn_2)
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/of.h:1481:2: note: expanded from macro '_OF_DECLARE'
    1481 |         _OF_DECLARE_STUB(table, name, compat, fn, fn_type)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/of.h:1470:16: note: expanded from macro '_OF_DECLARE_STUB'
    1470 |                      .data = (fn == (fn_type)NULL) ? fn : fn }
         |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   2 errors generated.
--
>> drivers/irqchip/irq-mchp-eic.c:275:1: error: call to undeclared function '__typecheck'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     275 | IRQCHIP_MATCH("microchip,sama7g5-eic", mchp_eic_init)
         | ^
   include/linux/irqchip.h:45:17: note: expanded from macro 'IRQCHIP_MATCH'
      45 |                                     .data = typecheck_irq_init_cb(fn), },
         |                                             ^
   include/linux/irqchip.h:24:3: note: expanded from macro 'typecheck_irq_init_cb'
      24 |         (__typecheck(typecheck_irq_init_cb, &fn) ? fn : fn)
         |          ^
>> drivers/irqchip/irq-mchp-eic.c:275:1: error: initializer element is not a compile-time constant
     275 | IRQCHIP_MATCH("microchip,sama7g5-eic", mchp_eic_init)
         | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/irqchip.h:45:17: note: expanded from macro 'IRQCHIP_MATCH'
      45 |                                     .data = typecheck_irq_init_cb(fn), },
         |                                             ^~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/irqchip.h:24:2: note: expanded from macro 'typecheck_irq_init_cb'
      24 |         (__typecheck(typecheck_irq_init_cb, &fn) ? fn : fn)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   2 errors generated.


vim +/__typecheck +288 drivers/irqchip/irq-mips-cpu.c

0916b46962cbcac arch/mips/kernel/irq_cpu.c     Gabor Juhos       2013-01-31  281  
afe8dc254711b72 arch/mips/kernel/irq_cpu.c     Andrew Bresticker 2014-09-18  282  int __init mips_cpu_irq_of_init(struct device_node *of_node,
0f84c305351c993 arch/mips/kernel/irq_cpu.c     Andrew Bresticker 2014-09-18  283  				struct device_node *parent)
0f84c305351c993 arch/mips/kernel/irq_cpu.c     Andrew Bresticker 2014-09-18  284  {
0f84c305351c993 arch/mips/kernel/irq_cpu.c     Andrew Bresticker 2014-09-18  285  	__mips_cpu_irq_init(of_node);
0916b46962cbcac arch/mips/kernel/irq_cpu.c     Gabor Juhos       2013-01-31  286  	return 0;
0916b46962cbcac arch/mips/kernel/irq_cpu.c     Gabor Juhos       2013-01-31  287  }
892b8cf06d8a1e7 drivers/irqchip/irq-mips-cpu.c Paul Burton       2015-05-24 @288  IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

RE: [PATCH next resend 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.

[David Laight]

> From: kernel test robot <lkp@intel.com>
> Sent: 25 July 2023 19:33
...
> 
> All errors (new ones prefixed by >>):
> 
> >> drivers/irqchip/irq-mips-cpu.c:288:1: error: call to undeclared function '__typecheck'; ISO C99 and
> later do not support implicit function declarations [-Wimplicit-function-declaration]
>      288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
>          | ^
>    include/linux/irqchip.h:37:38: note: expanded from macro 'IRQCHIP_DECLARE'
>       37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
>          |                                             ^
>    include/linux/irqchip.h:24:3: note: expanded from macro 'typecheck_irq_init_cb'
>       24 |         (__typecheck(typecheck_irq_init_cb, &fn) ? fn : fn)
>          |          ^
> >> drivers/irqchip/irq-mips-cpu.c:288:1: error: initializer element is not a compile-time constant
>      288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
>          | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/irqchip.h:37:2: note: expanded from macro 'IRQCHIP_DECLARE'
>       37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
>          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/of.h:1493:3: note: expanded from macro 'OF_DECLARE_2'
>     1493 |                 _OF_DECLARE(table, name, compat, fn, of_init_fn_2)
>          |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/of.h:1481:2: note: expanded from macro '_OF_DECLARE'
>     1481 |         _OF_DECLARE_STUB(table, name, compat, fn, fn_type)
>          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/of.h:1470:16: note: expanded from macro '_OF_DECLARE_STUB'
>     1470 |                      .data = (fn == (fn_type)NULL) ? fn : fn }
>          |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It looks like irqchip.h is using __typecheck() which is really
an internal part of the implementation of min() and max().
The patched version doesn't use it - hence the build fail.
I can re-instate it, but this all looks wrong to me.

The type of typecheck_irq_init_cb is the same as that of fn_type (although
they are defined separately).
Both headers seem to be testing the type - and it must match both.
So if the test in of.h worked the one in irqchip.h wouldn't have been added.
So I suspect it doesn't actually do anything - the RHS is NULL, the type
probably doesn't matter.

Possibly:
		.data = {sizeof ((fn) == (fn_type)(fn)) ? fn : fn }
would actually generate the required compile-time error.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

Re: [PATCH next resend 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.

[Marc Zyngier]

On Wed, 26 Jul 2023 10:19:48 +0100,
David Laight <David.Laight@ACULAB.COM> wrote:
> 
> > From: kernel test robot <lkp@intel.com>
> > Sent: 25 July 2023 19:33
> ...
> > 
> > All errors (new ones prefixed by >>):
> > 
> > >> drivers/irqchip/irq-mips-cpu.c:288:1: error: call to undeclared function '__typecheck'; ISO C99 and
> > later do not support implicit function declarations [-Wimplicit-function-declaration]
> >      288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
> >          | ^
> >    include/linux/irqchip.h:37:38: note: expanded from macro 'IRQCHIP_DECLARE'
> >       37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
> >          |                                             ^
> >    include/linux/irqchip.h:24:3: note: expanded from macro 'typecheck_irq_init_cb'
> >       24 |         (__typecheck(typecheck_irq_init_cb, &fn) ? fn : fn)
> >          |          ^
> > >> drivers/irqchip/irq-mips-cpu.c:288:1: error: initializer element is not a compile-time constant
> >      288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
> >          | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >    include/linux/irqchip.h:37:2: note: expanded from macro 'IRQCHIP_DECLARE'
> >       37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
> >          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >    include/linux/of.h:1493:3: note: expanded from macro 'OF_DECLARE_2'
> >     1493 |                 _OF_DECLARE(table, name, compat, fn, of_init_fn_2)
> >          |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >    include/linux/of.h:1481:2: note: expanded from macro '_OF_DECLARE'
> >     1481 |         _OF_DECLARE_STUB(table, name, compat, fn, fn_type)
> >          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >    include/linux/of.h:1470:16: note: expanded from macro '_OF_DECLARE_STUB'
> >     1470 |                      .data = (fn == (fn_type)NULL) ? fn : fn }
> >          |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> It looks like irqchip.h is using __typecheck() which is really
> an internal part of the implementation of min() and max().
> The patched version doesn't use it - hence the build fail.
> I can re-instate it, but this all looks wrong to me.

Please see f1985002839a ("irqchip: Provide stronger type checking for
IRQCHIP_MATCH/IRQCHIP_DECLARE") for the rationale.

Given that this has uncovered a number of bugs, I'm not letting this
go without an equivalent replacement.

> The type of typecheck_irq_init_cb is the same as that of fn_type (although
> they are defined separately).
> Both headers seem to be testing the type - and it must match both.
> So if the test in of.h worked the one in irqchip.h wouldn't have been added.
> So I suspect it doesn't actually do anything - the RHS is NULL, the type
> probably doesn't matter.

They are used in different contexts. See IRQCHIP_MATCH().

	M.

-- 
Without deviation from the norm, progress is not possible.

RE: [PATCH next resend 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.

[David Laight]

From: Marc Zyngier
> Sent: 26 July 2023 10:51
> 
> On Wed, 26 Jul 2023 10:19:48 +0100,
> David Laight <David.Laight@ACULAB.COM> wrote:
> >
> > > From: kernel test robot <lkp@intel.com>
> > > Sent: 25 July 2023 19:33
> > ...
> > >
> > > All errors (new ones prefixed by >>):
> > >
> > > >> drivers/irqchip/irq-mips-cpu.c:288:1: error: call to undeclared function '__typecheck'; ISO C99
> and
> > > later do not support implicit function declarations [-Wimplicit-function-declaration]
> > >      288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
> > >          | ^
> > >    include/linux/irqchip.h:37:38: note: expanded from macro 'IRQCHIP_DECLARE'
> > >       37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
> > >          |                                             ^
> > >    include/linux/irqchip.h:24:3: note: expanded from macro 'typecheck_irq_init_cb'
> > >       24 |         (__typecheck(typecheck_irq_init_cb, &fn) ? fn : fn)
> > >          |          ^
> > > >> drivers/irqchip/irq-mips-cpu.c:288:1: error: initializer element is not a compile-time constant
> > >      288 | IRQCHIP_DECLARE(cpu_intc, "mti,cpu-interrupt-controller", mips_cpu_irq_of_init);
> > >          | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >    include/linux/irqchip.h:37:2: note: expanded from macro 'IRQCHIP_DECLARE'
> > >       37 |         OF_DECLARE_2(irqchip, name, compat, typecheck_irq_init_cb(fn))
> > >          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >    include/linux/of.h:1493:3: note: expanded from macro 'OF_DECLARE_2'
> > >     1493 |                 _OF_DECLARE(table, name, compat, fn, of_init_fn_2)
> > >          |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >    include/linux/of.h:1481:2: note: expanded from macro '_OF_DECLARE'
> > >     1481 |         _OF_DECLARE_STUB(table, name, compat, fn, fn_type)
> > >          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >    include/linux/of.h:1470:16: note: expanded from macro '_OF_DECLARE_STUB'
> > >     1470 |                      .data = (fn == (fn_type)NULL) ? fn : fn }
> > >          |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > It looks like irqchip.h is using __typecheck() which is really
> > an internal part of the implementation of min() and max().
> > The patched version doesn't use it - hence the build fail.
> > I can re-instate it, but this all looks wrong to me.
> 
> Please see f1985002839a ("irqchip: Provide stronger type checking for
> IRQCHIP_MATCH/IRQCHIP_DECLARE") for the rationale.
> 
> Given that this has uncovered a number of bugs, I'm not letting this
> go without an equivalent replacement.
..
> 
> They are used in different contexts. See IRQCHIP_MATCH().

Ah, I was seeing the error in the expansion of IRQCHIP_DECLARE()
which is doing the type check twice.
It can just pass 'fn'.

The cast NULL check does work.
So IRQCHIP_MATCH() can use the simpler 'fn = (fn_type)NULL ? fn : fn' test
that _OF_DECLARE_STUB() uses.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)