On Mon, Aug 14, 2023 at 08:58:34AM +0200, Krzysztof Kozlowski wrote: > On 10/08/2023 17:44, Greg Kroah-Hartman wrote: > > On Thu, Aug 10, 2023 at 10:50:42AM +0200, Krzysztof Kozlowski wrote: > >> `devtype` is enum, thus cast of pointer on 64-bit compile test with W=1 > >> causes: > >> > >> mxs-auart.c:1598:15: error: cast to smaller integer type 'enum mxs_auart_type' from 'const void *' [-Werror,-Wvoid-pointer-to-enum-cast] > >> > >> Cc: Andi Shyti <andi.shyti@xxxxxxxxxx> > >> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> > >> --- > >> drivers/tty/serial/mxs-auart.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c > >> index 8eeecf8ad359..a9b32722b049 100644 > >> --- a/drivers/tty/serial/mxs-auart.c > >> +++ b/drivers/tty/serial/mxs-auart.c > >> @@ -1595,7 +1595,7 @@ static int mxs_auart_probe(struct platform_device *pdev) > >> return -EINVAL; > >> } > >> > >> - s->devtype = (enum mxs_auart_type)of_device_get_match_data(&pdev->dev); > >> + s->devtype = (uintptr_t)of_device_get_match_data(&pdev->dev); > > > > This feels like a compiler issue as devtype is a enum mxs_auart_type > > variable, so the cast shoudl be correct. > > While the cast is obviously safe here, the warning in general is > reasonable - people were make too many mistakes by assuming pointers are > integers... But this isn't a pointer, it's an enumerated type thrown into a void *, so cast it properly (void * == unsigned long). > Just for the record (not saying that others doing is proof of correctness): > > https://lore.kernel.org/lkml/20230809-cbl-1903-v1-1-df9d66a3ba3e@xxxxxxxxxx/T/ > > But maybe Nathan can share his thoughts whether we should just disable > this warning for kernel? I thought that Linus had some objection to the compilers doing something foolish here as well, but I can't find it in my archives at the moment (am traveling). > > And if not, unitptr_t isn't a valid kernel type, so that's not a good > > It is in include/linux/types.h, so do you mean that it is not > recommended for in-kernel usage? I can go with kernel_ulong_t - which is > a kernel type - if the cast is agreed. not recommended for in-kernel usage. thanks, greg k-h
