Re: [PATCH] ELF: supply userspace with available page shifts (AT_PAGE_SHIFT_LIST)

Alexey Dobriyan
2023-12-05T14:26:26Z

On Tue, Dec 05, 2023 at 10:51:39AM +0100, Florian Weimer wrote:
> * Alexey Dobriyan:
>
> > +/*
> > + * Page sizes available for mmap(2) encoded as 1 page shift per byte in
> > + * increasing order.
> > + *
> > + * Thus 32-bit systems get 4 shifts, 64-bit systems get 8 shifts tops.
>
> Couldn't you use the bits in a long instead, to indicate which shifts
> are present? That's always going to be enough.

Yes!

I was so proud of myself for this line:

val |= 21 << (s += 8);

Now it is boring bitmask again :-)