From: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
To: Dave Hansen <dave-gkUM19QKKo4@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
dave.hansen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org
Subject: Re: [PATCH 2/9] mm: implement new pkey_mprotect() system call
Date: Sat, 11 Jun 2016 11:47:44 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.11.1606111147000.5839@nanos> (raw)
In-Reply-To: <20160609000120.A3DD5140-LXbPSdftPKxrdx17CPfAsdBPR1lH4CV8@public.gmane.org>
On Wed, 8 Jun 2016, Dave Hansen wrote:
> Proposed semantics:
> 1. protection key 0 is special and represents the default,
> unassigned protection key. It is always allocated.
> 2. mprotect() never affects a mapping's pkey_mprotect()-assigned
> protection key. A protection key of 0 (even if set explicitly)
> represents an unassigned protection key.
> 2a. mprotect(PROT_EXEC) on a mapping with an assigned protection
> key may or may not result in a mapping with execute-only
> properties. pkey_mprotect() plus pkey_set() on all threads
> should be used to _guarantee_ execute-only semantics.
> 3. mprotect(PROT_EXEC) may result in an "execute-only" mapping. The
> kernel will internally attempt to allocate and dedicate a
> protection key for the purpose of execute-only mappings. This
> may not be possible in cases where there are no free protection
> keys available.
Shouldn't we just reserve a protection key for PROT_EXEC unconditionally?
Thanks,
tglx
next prev parent reply other threads:[~2016-06-11 9:47 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-09 0:01 [PATCH 0/9] [v3] System Calls for Memory Protection Keys Dave Hansen
2016-06-09 0:01 ` [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit Dave Hansen
2016-06-09 0:01 ` [PATCH 2/9] mm: implement new pkey_mprotect() system call Dave Hansen
[not found] ` <20160609000120.A3DD5140-LXbPSdftPKxrdx17CPfAsdBPR1lH4CV8@public.gmane.org>
2016-06-11 9:47 ` Thomas Gleixner [this message]
2016-06-13 16:03 ` Dave Hansen
2016-06-09 0:01 ` [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen
2016-06-09 0:01 ` [PATCH 4/9] x86: wire up mprotect_key() system call Dave Hansen
2016-06-09 0:01 ` [PATCH 5/9] x86, pkeys: allocation/free syscalls Dave Hansen
2016-06-09 0:01 ` [PATCH 6/9] x86, pkeys: add pkey set/get syscalls Dave Hansen
2016-06-09 0:01 ` [PATCH 7/9] generic syscalls: wire up memory protection keys syscalls Dave Hansen
2016-06-09 0:01 ` [PATCH 8/9] pkeys: add details of system call use to Documentation/ Dave Hansen
[not found] ` <20160609000117.71AC7623-LXbPSdftPKxrdx17CPfAsdBPR1lH4CV8@public.gmane.org>
2016-06-09 0:01 ` [PATCH 9/9] x86, pkeys: add self-tests Dave Hansen
2016-06-30 9:41 ` [PATCH 0/9] [v3] System Calls for Memory Protection Keys Ingo Molnar
[not found] ` <20160630094123.GA29268-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-06-30 16:46 ` Dave Hansen
2016-06-30 17:40 ` Andy Lutomirski
-- strict thread matches above, loose matches on Subject: below --
2016-07-07 12:47 [PATCH 0/9] [REVIEW-REQUEST] [v4] " Dave Hansen
2016-07-07 12:47 ` [PATCH 2/9] mm: implement new pkey_mprotect() system call Dave Hansen
2016-07-07 14:40 ` Mel Gorman
2016-07-07 16:51 ` Dave Hansen
2016-07-08 10:15 ` Mel Gorman
2016-06-07 20:47 [PATCH 0/9] [v2] System Calls for Memory Protection Keys Dave Hansen
2016-06-07 20:47 ` [PATCH 2/9] mm: implement new pkey_mprotect() system call Dave Hansen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.2.11.1606111147000.5839@nanos \
--to=tglx-hfztesqfncyowbw4kg4ksq@public.gmane.org \
--cc=akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org \
--cc=dave-gkUM19QKKo4@public.gmane.org \
--cc=dave.hansen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org \
--cc=linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org \
--cc=torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org \
--cc=x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).