From: Ram Pai <linuxram@us.ibm.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: mpe@ellerman.id.au, mingo@redhat.com, akpm@linux-foundation.org,
linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
x86@kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org, benh@kernel.crashing.org,
paulus@samba.org, khandual@linux.vnet.ibm.com,
aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com,
hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com,
ebiederm@xmission.com, corbet@lwn.net, arnd@arndb.de,
fweimer@redhat.com, msuchanek@suse.com,
Ulrich.Weigand@de.ibm.com
Subject: Re: [PATCH] x86, powerpc : pkey-mprotect must allow pkey-0
Date: Fri, 9 Mar 2018 21:55:44 -0800 [thread overview]
Message-ID: <20180310055544.GU1060@ram.oc3035372033.ibm.com> (raw)
In-Reply-To: <60886e4a-59d4-541a-a6af-d4504e6719ad@intel.com>
On Fri, Mar 09, 2018 at 02:40:32PM -0800, Dave Hansen wrote:
> On 03/09/2018 12:12 AM, Ram Pai wrote:
> > Once an address range is associated with an allocated pkey, it cannot be
> > reverted back to key-0. There is no valid reason for the above behavior. On
> > the contrary applications need the ability to do so.
>
> Why don't we just set pkey 0 to be allocated in the allocation bitmap by
> default?
ok. that will make it allocatable. But it will not be associatable,
given the bug in the current code. And what will be the
default key associated with a pte? zero? or something else?
>
> We *could* also just not let it be special and let it be freed. An app
> could theoretically be careful and make sure nothing is using it.
unable to see how this solves the problem. Need some more explaination.
RP
next prev parent reply other threads:[~2018-03-10 5:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-09 8:12 [PATCH] x86, powerpc : pkey-mprotect must allow pkey-0 Ram Pai
2018-03-09 8:37 ` Balbir Singh
2018-03-09 19:54 ` Ram Pai
2018-03-09 8:43 ` Ingo Molnar
2018-03-09 20:09 ` Ram Pai
2018-03-09 10:19 ` Michael Ellerman
2018-03-09 20:06 ` Ram Pai
2018-03-12 15:46 ` Dave Hansen
2018-03-09 11:04 ` Florian Weimer
2018-03-09 20:00 ` Ram Pai
2018-03-14 8:00 ` Florian Weimer
2018-03-14 8:05 ` Florian Weimer
2018-03-14 14:08 ` Dave Hansen
2018-03-09 22:40 ` Dave Hansen
2018-03-10 5:55 ` Ram Pai [this message]
2018-03-10 6:50 ` Dave Hansen
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