From: Rich Felker <dalias@libc.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>,
mtk.manpages@gmail.com, nd@arm.com, linux-man@vger.kernel.org,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: glibc and linux-man disagrees about pkey_alloc
Date: Wed, 16 May 2018 11:18:44 -0400 [thread overview]
Message-ID: <20180516151844.GX1392@brightrain.aerifal.cx> (raw)
In-Reply-To: <1f2551f3-3d6d-3905-433e-967af2c3be87@redhat.com>
On Wed, May 16, 2018 at 04:36:03PM +0200, Florian Weimer wrote:
> On 05/16/2018 01:10 PM, Szabolcs Nagy wrote:
> >glibc sysdeps/unix/sysv/linux/bits/mman-shared.h:
> >
> >int pkey_alloc (unsigned int __flags, unsigned int
> >__access_rights) __THROW;
> >
> >linux-man http://man7.org/linux/man-pages/man2/pkey_alloc.2.html :
> >
> >int pkey_alloc(unsigned long flags, unsigned long access_rights);
> >
> >i assume the documentation should be fixed (as the glibc
> >code is already in use)
>
> unsigned long on the kernel side is unsigned long long in userspace
> for the x32 variant of x86-64, so the kernel types aren't that
> helpful for describing the user-space interface in an
> architecture-independent fashion. I expect the flags to be
> consistent across architectures, so there can only be 32 of them
> anyway, and access rights currently use two bits on x86 (and three
> on POWER, I think).
There's possibly some argument to be made that by the time 32 bits are
filled, 32-bit archs will be legacy-only and won't be getting new pkey
hardware features, in which case having the full 64 bits available
would be nice... But I don't really care what decision is made as long
as it's consistent.
Rich
prev parent reply other threads:[~2018-05-16 15:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-16 11:10 glibc and linux-man disagrees about pkey_alloc Szabolcs Nagy
2018-05-16 11:19 ` Dmitry V. Levin
2018-05-16 11:33 ` Szabolcs Nagy
2018-05-18 15:26 ` Michael Kerrisk (man-pages)
2018-05-16 14:36 ` Florian Weimer
2018-05-16 15:18 ` Rich Felker [this message]
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