linux-kernel - Re: [PATCH] ELF: supply userspace with available page shifts (AT_PAGE_SHIFT

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Message-ID: <87v89dvuxg.fsf@oldenburg.str.redhat.com>
Date:   Tue, 05 Dec 2023 10:51:39 +0100
From:   Florian Weimer <fweimer@...hat.com>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
        x86@...nel.org
Subject: Re: [PATCH] ELF: supply userspace with available page shifts
 (AT_PAGE_SHIFT_LIST)

* 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.

Thanks,
Florian