Re: [PATCH 4/4] asm-generic/bitsperlong.h: Add sanity checks for __BITS_PER_LONG

Arnd Bergmann
2026-01-19T14:58:11Z

On Mon, Jan 19, 2026, at 14:41, Thomas Weißschuh wrote:
> On Mon, Jan 19, 2026 at 01:45:04PM +0100, Arnd Bergmann wrote:
>> On Mon, Jan 19, 2026, at 11:56, Thomas Weißschuh wrote:
>> > On Mon, Jan 19, 2026 at 10:37:58AM +0000, David Laight wrote:
>> >>
>> >> Don't you need a check that it isn't wrong on a user system?
>> >> Which is what I thought it was doing.
>> >
>> > Not really. The overrides defined by arch/*/include/uapi/asm/bitsperlong.h are
>> > being tested here. If they work in the kernel build I assume they also work
>> > in userspace.
>>
>> I think You could just move check into include/asm-generic/bitsperlong.h
>> to make this more obvious with the #ifdef __KERNEL__, and remove the
>> disabled check from my original version there.
>
> Ok. I'd like to keep your existing test though, as it tests something different
> and it would be nice to have that too at some point.

Sure, that works too. I wonder if one of the recent vdso cleanups
also happened to address the problem with the incorrect BITS_PER_LONG
being visible in the vdso code. Maybe we can already turn that on again.

Arnd