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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: mm, x86, powerpc: pkey semantics for key-0 ?
Date: Thu, 8 Mar 2018 10:25:17 -0800	[thread overview]
Message-ID: <20180308182517.GO1060@ram.oc3035372033.ibm.com> (raw)
In-Reply-To: <2a7737cf-a5ba-c814-fdc7-45b5cdd47376@intel.com>

Dave,

Is there a reason why the default key; key-0, is not allowed to be
explicitly associated with pages using pkey_mprotect()?

I see valid usecases where an application may initially want to
associate an address-range with some key and latter choose to revert to
its initial state, by associating key-0.  However our implementation
(both x86 and power) do not allow pkey_mprotect() to be called with
key-0.

I do not see a reason why it must be blocked.

Thoughts?
RP

  reply	other threads:[~2018-03-08 18:25 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-21 23:52 [PATCH v12 0/3] mm, x86, powerpc: Enhancements to Memory Protection Keys Ram Pai
2018-02-21 23:52 ` [PATCH v12 1/3] mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS is enabled Ram Pai
2018-02-23  7:11   ` kbuild test robot
2018-02-24  1:05     ` Ram Pai
2018-02-25 11:57       ` Aneesh Kumar K.V
2018-02-26  7:26         ` Ram Pai
2018-02-23  8:06   ` kbuild test robot
2018-02-26 21:12   ` Dave Hansen
2018-02-21 23:52 ` [PATCH v12 2/3] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey Ram Pai
2018-02-26 21:14   ` Dave Hansen
2018-02-21 23:52 ` [PATCH v12 3/3] mm, x86, powerpc: display pkey in smaps only if arch supports pkeys Ram Pai
2018-02-26 21:16   ` Dave Hansen
2018-03-08 18:25     ` Ram Pai [this message]
2018-03-08 19:30       ` mm, x86, powerpc: pkey semantics for key-0 ? Dave Hansen

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