Hi Adrian, On Tue, Jan 17, 2023 at 5:42 PM John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx> wrote: > On 1/6/23 16:17, Geert Uytterhoeven wrote: > >> I'm not seeing this one, but I am getting this one instead: > >> > >> In file included from ./arch/sh/include/asm/hw_irq.h:6, > >> from ./include/linux/irq.h:596, > >> from ./include/asm-generic/hardirq.h:17, > >> from ./arch/sh/include/asm/hardirq.h:9, > >> from ./include/linux/hardirq.h:11, > >> from ./include/linux/interrupt.h:11, > >> from ./include/linux/serial_core.h:13, > >> from ./include/linux/serial_sci.h:6, > >> from arch/sh/kernel/cpu/sh2/setup-sh7619.c:11: > >> ./include/linux/sh_intc.h:100:63: error: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Werror=sizeof-pointer-div] > >> 100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) > >> | ^ > >> ./include/linux/sh_intc.h:105:31: note: in expansion of macro '_INTC_ARRAY' > >> 105 | _INTC_ARRAY(vectors), _INTC_ARRAY(groups), \ > >> | ^~~~~~~~~~~ > > > > The easiest fix for the latter is to disable CONFIG_WERROR. > > Unfortunately I don't know a simple solution to get rid of the warning. > > I did some research and it seems that what the macro _INT_ARRAY() does with "sizeof(a)/sizeof(*a)" > is a commonly used way to calculate array sizes and the kernel has even its own macro for that > called ARRAY_SIZE() which Linus asks people to use here [1]. > > So, I replaced _INTC_ARRAY() with ARRAY_SIZE() (see below), however the kernel's own ARRAY_SIZE() > macro triggers the same compiler warning. I'm CC'ing Michael Karcher who has more knowledge on > writing proper C code than me and maybe an idea how to fix this warning. > > Thanks, > Adrian > > > [1] https://lkml.org/lkml/2015/9/3/428 > > diff --git a/include/linux/sh_intc.h b/include/linux/sh_intc.h > index c255273b0281..07a187686a84 100644 > --- a/include/linux/sh_intc.h > +++ b/include/linux/sh_intc.h > @@ -97,14 +97,12 @@ struct intc_hw_desc { > unsigned int nr_subgroups; > }; > > -#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) > - > #define INTC_HW_DESC(vectors, groups, mask_regs, \ > prio_regs, sense_regs, ack_regs) \ > { \ > - _INTC_ARRAY(vectors), _INTC_ARRAY(groups), \ > - _INTC_ARRAY(mask_regs), _INTC_ARRAY(prio_regs), \ > - _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \ > + ARRAY_SIZE(vectors), ARRAY_SIZE(groups), \ > + ARRAY_SIZE(mask_regs), ARRAY_SIZE(prio_regs), \ > + ARRAY_SIZE(sense_regs), ARRAY_SIZE(ack_regs), \ > } The issue is that some of the parameters are not arrays, but NULL. E.g.: arch/sh/kernel/cpu/sh2/setup-sh7619.c:static DECLARE_INTC_DESC(intc_desc, "sh7619", vectors, NULL, arch/sh/kernel/cpu/sh2/setup-sh7619.c- NULL, prio_registers, NULL); -- Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
