From: Marc Zyngier
> Sent: 26 July 2023 10:51
>
> On Wed, 26 Jul 2023 10:19:48 +0100,
> David Laight <David.Laight@xxxxxxxxxx> wrote:
> >
> > > From: kernel test robot <lkp@xxxxxxxxx>
> > > 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
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