From: Florian Weimer <fweimer@redhat.com>
To: Vlastimil Babka <vbabka@suse.cz>,
Dave Hansen <dave.hansen@linux.intel.com>,
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: Wed, 22 Nov 2017 13:15:24 +0100 [thread overview]
Message-ID: <813f9736-36dd-b2e5-c850-9f2d5f94514a@redhat.com> (raw)
In-Reply-To: <8741e4d6-6ac0-9c07-99f3-95d8d04940b4@suse.cz>
On 11/22/2017 09:18 AM, Vlastimil Babka wrote:
> And, was the pkey == -1 internal wiring supposed to be exposed to the
> pkey_mprotect() signal, or should there have been a pre-check returning
> EINVAL in SYSCALL_DEFINE4(pkey_mprotect), before calling
> do_mprotect_pkey())? I assume it's too late to change it now anyway (or
> not?), so should we also document it?
I think the -1 case to the set the default key is useful because it
allows you to use a key value of -1 to mean “MPK is not supported”, and
still call pkey_mprotect.
I plan to document this behavior on the glibc side, and glibc will call
mprotect (not pkey_mprotect) for key -1, so that you won't get ENOSYS
with kernels which do not support pkey_mprotect.
Thanks,
Florian
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next prev parent reply other threads:[~2017-11-22 12:15 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 ` Florian Weimer [this message]
2017-11-22 12:46 ` MPK: removing a pkey 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
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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