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From: Ram Pai <linuxram@us.ibm.com>
To: "Michal Suchánek" <msuchanek@suse.de>
Cc: fweimer@redhat.com, Dave Hansen <dave.hansen@intel.com>,
	Ingo Molnar <mingo@kernel.org>,
	mhocko@kernel.org, Ulrich.Weigand@de.ibm.com, paulus@samba.org,
	aneesh.kumar@linux.vnet.ibm.com, bauerman@linux.vnet.ibm.com,
	Thomas Gleixner <tglx@linutronix.de>,
	linuxppc-dev@lists.ozlabs.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v3] powerpc, pkey: make protection key 0 less special
Date: Tue, 8 May 2018 11:38:53 -0700	[thread overview]
Message-ID: <20180508183853.GA5802@ram.oc3035372033.ibm.com> (raw)
In-Reply-To: <20180508190336.361a508b@naga.suse.cz>

On Tue, May 08, 2018 at 07:03:36PM +0200, Michal Suchánek wrote:
> 
> How is the application denied setting the permissions on key 0 if it
> can program the register directly?

There is a UAMOR register. The userspace can change the permissions of a
given key; by modifying the bits in AMOR register, only if the kernel
has set the corresponding bit in the UAMOR register.  For key-0 the
kernel does not set the corresponding UAMOR bit.

RP

  reply	other threads:[~2018-05-08 18:39 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-04 19:22 [PATCH v3] powerpc, pkey: make protection key 0 less special Ram Pai
2018-05-04 19:59 ` Dave Hansen
2018-05-04 20:21   ` Ram Pai
2018-05-04 21:26 ` Michal Suchánek
2018-05-04 21:31   ` Dave Hansen
2018-05-04 21:45     ` Ram Pai
2018-05-05 12:39       ` Michal Suchánek
2018-05-06 20:10         ` Ram Pai
2018-05-07 11:21           ` Michal Suchánek
2018-05-08 16:38             ` Ram Pai
2018-05-08 17:03               ` Michal Suchánek
2018-05-08 18:38                 ` Ram Pai [this message]
2018-05-09 15:43 ` Michal Suchánek
2018-05-09 15:46   ` Dave Hansen
2018-05-09 15:56     ` Michal Suchánek

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