linux-kernel - Re: [PATCH v2] ELF: supply userspace with available page shifts (AT_PAGE_SHIFT

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Message-ID: <202312061308.630C56CCA@keescook>
Date:   Wed, 6 Dec 2023 13:09:01 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Florian Weimer <fweimer@...hat.com>
Cc:     Alexey Dobriyan <adobriyan@...il.com>,
        Andrew Morton <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 v2] ELF: supply userspace with available page shifts
 (AT_PAGE_SHIFT_MASK)

On Wed, Dec 06, 2023 at 10:05:36PM +0100, Florian Weimer wrote:
> * Kees Cook:
> 
> > On Tue, Dec 05, 2023 at 07:01:34PM +0300, Alexey Dobriyan wrote:
> >> Report available page shifts in arch independent manner, so that
> >> userspace developers won't have to parse /proc/cpuinfo hunting
> >> for arch specific strings:
> >> 
> >> Note!
> >> 
> >> This is strictly for userspace, if some page size is shutdown due
> >> to kernel command line option or CPU bug workaround, than is must not
> >> be reported in aux vector!
> >
> > Given Florian in CC, I assume this is something glibc would like to be
> > using? Please mention this in the commit log.
> 
> Nope, I just wrote a random drive-by comment on the first version.

Ah, okay. Then Alexey, who do you expect to be the consumer of this new
AT value?

-- 
Kees Cook