From: Florian Weimer <fweimer@redhat.com>
To: Dave Hansen <dave.hansen@linux.intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-x86_64@vger.kernel.org, linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>, Linux API <linux-api@vger.kernel.org>
Subject: Re: MPK: removing a pkey
Date: Fri, 24 Nov 2017 09:35:31 +0100 [thread overview]
Message-ID: <e97e53a1-ba04-c62e-cc64-054b488d5394@redhat.com> (raw)
In-Reply-To: <8051353f-47d3-37a4-a402-41adc8b6eb88@linux.intel.com>
On 11/24/2017 12:29 AM, Dave Hansen wrote:
> Although weird, the thought here was that pkey_mprotect() callers are
> new and should know about the interactions with PROT_EXEC. They can
> also*get* PROT_EXEC semantics if they want.
>
> The only wart here is if you do:
>
> mprotect(..., PROT_EXEC); // key 10 is now the PROT_EXEC key
I thought the PROT_EXEC key is always 1?
> pkey_mprotect(..., PROT_EXEC, key=3);
>
> I'm not sure what this does. We should probably ensure that it returns
> an error.
Without protection key support, PROT_EXEC would imply PROT_READ with an
ordinary mprotect. I think it makes sense to stick to this behavior.
It is what I have documented for glibc:
<https://sourceware.org/ml/libc-alpha/2017-11/msg00841.html>
Thanks,
Florian
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next prev parent reply other threads:[~2017-11-24 8:35 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-05 10:35 MPK: pkey_free and key reuse Florian Weimer
2017-11-08 20:41 ` Dave Hansen
2017-11-09 14:48 ` Florian Weimer
2017-11-09 16:59 ` Dave Hansen
2017-11-23 12:48 ` Florian Weimer
2017-11-23 13:07 ` Vlastimil Babka
2017-11-23 15:25 ` Dave Hansen
2017-11-24 14:55 ` Florian Weimer
[not found] ` <0f006ef4-a7b5-c0cf-5f58-d0fd1f911a54-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-11-22 8:18 ` MPK: removing a pkey (was: pkey_free and key reuse) Vlastimil Babka
2017-11-22 12:15 ` MPK: removing a pkey Florian Weimer
2017-11-22 12:46 ` Vlastimil Babka
[not found] ` <f0495f01-9821-ec36-56b4-333f109eb761-AlSwsSmVLrQ@public.gmane.org>
2017-11-22 12:49 ` Florian Weimer
2017-11-22 16:10 ` Dave Hansen
2017-11-22 16:21 ` Florian Weimer
[not found] ` <9ec19ff3-86f6-7cfe-1a07-1ab1c5d9882c-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-11-22 16:32 ` Dave Hansen
2017-11-23 8:11 ` Vlastimil Babka
[not found] ` <de93997a-7802-96cf-62e2-e59416e745ca-AlSwsSmVLrQ@public.gmane.org>
2017-11-23 15:00 ` Dave Hansen
2017-11-23 21:42 ` Vlastimil Babka
[not found] ` <2d12777f-615a-8101-2156-cf861ec13aa7-AlSwsSmVLrQ@public.gmane.org>
2017-11-23 23:29 ` Dave Hansen
2017-11-24 8:35 ` Florian Weimer [this message]
2017-11-24 8:38 ` Vlastimil Babka
2017-11-23 12:38 ` Florian Weimer
2017-11-23 15:09 ` Dave Hansen
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