From: Alexey Dobriyan <adobriyan@gmail.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
x86@kernel.org
Subject: Re: [PATCH] ELF: supply userspace with available page shifts (AT_PAGE_SHIFT_LIST)
Date: Tue, 5 Dec 2023 17:26:22 +0300 [thread overview]
Message-ID: <75344429-1f34-4a14-ab10-8613846d694e@p183> (raw)
In-Reply-To: <87v89dvuxg.fsf@oldenburg.str.redhat.com>
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 :-)
next prev parent reply other threads:[~2023-12-05 14:26 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-04 17:18 [PATCH] ELF: supply userspace with available page shifts (AT_PAGE_SHIFT_LIST) Alexey Dobriyan
2023-12-05 9:51 ` Florian Weimer
2023-12-05 14:26 ` Alexey Dobriyan [this message]
2023-12-05 16:01 ` [PATCH v2] ELF: supply userspace with available page shifts (AT_PAGE_SHIFT_MASK) Alexey Dobriyan
2023-12-06 20:47 ` Kees Cook
2023-12-06 21:05 ` Florian Weimer
2023-12-06 21:09 ` Kees Cook
2023-12-07 15:04 ` Alexey Dobriyan
2023-12-07 14:57 ` Alexey Dobriyan
2023-12-07 15:32 ` Florian Weimer
2023-12-08 18:29 ` Kees Cook
2023-12-08 18:35 ` Florian Weimer
2023-12-08 18:38 ` Kees Cook
2023-12-09 9:44 ` Alexey Dobriyan
2023-12-07 18:44 ` [PATCH v3] ELF: AT_PAGE_SHIFT_MASK -- supply userspace with available page shifts Alexey Dobriyan
2023-12-12 21:09 ` Kees Cook
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