From: Kees Cook <keescook@chromium.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <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 v2] ELF: supply userspace with available page shifts (AT_PAGE_SHIFT_MASK)
Date: Fri, 8 Dec 2023 10:38:07 -0800 [thread overview]
Message-ID: <202312081037.895E558@keescook> (raw)
In-Reply-To: <87lea4czki.fsf@oldenburg.str.redhat.com>
On Fri, Dec 08, 2023 at 07:35:25PM +0100, Florian Weimer wrote:
> * Kees Cook:
>
> > I significantly prefer APIs not being arch-specific, so I'd prefer we
> > always include AT_PAGE_SHIFT_MASK. For an architecture that doesn't
> > define its own ARCH_AT_PAGE_SHIFT_MASK, it's not _inaccurate_ to report
> > 1 << PAGE_SHIFT, but it might be incomplete.
>
> The downside is that as an application programmer, I have to go and
> chase for the information the legacy way if I encounter
> getauxval(AT_PAGE_SHIFT_MASK) == getpagesize() for a longer time
> because the interface does not signal the absence of any extended
> page sizes.
Are there architectures besides x86 where AT_PAGE_SHIFT_MASK isn't a
single bit? If so, let's get them added now along with x86.
--
Kees Cook
next prev parent reply other threads:[~2023-12-08 18:38 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
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 [this message]
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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