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From: Florian Weimer <fweimer@redhat.com>
To: Ram Pai <linuxram@us.ibm.com>,
	mpe@ellerman.id.au, mingo@redhat.com, akpm@linux-foundation.org
Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
	x86@kernel.org, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org, dave.hansen@intel.com,
	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, msuchanek@suse.com,
	Ulrich.Weigand@de.ibm.com
Subject: Re: [PATCH] x86, powerpc : pkey-mprotect must allow pkey-0
Date: Fri, 9 Mar 2018 12:04:49 +0100	[thread overview]
Message-ID: <ec90ed75-2810-bcc3-8439-8dc85a6b46ac@redhat.com> (raw)
In-Reply-To: <1520583161-11741-1-git-send-email-linuxram@us.ibm.com>

On 03/09/2018 09:12 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.

mprotect without a key does not necessarily use key 0, e.g. if 
protection keys are used to emulate page protection flag combination 
which is not directly supported by the hardware.

Therefore, it seems to me that filtering out non-allocated keys is the 
right thing to do.

Thanks,
Florian

  parent reply	other threads:[~2018-03-09 11:05 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 [this message]
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
2018-03-10  6:50     ` Dave Hansen

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