From: Florian Weimer <fweimer@redhat.com>
To: Andy Lutomirski <luto@kernel.org>, linuxram@us.ibm.com
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Linux-MM <linux-mm@kvack.org>,
Dave Hansen <dave.hansen@intel.com>
Subject: Re: pkeys on POWER: Access rights not reset on execve
Date: Sat, 19 May 2018 07:26:17 +0200 [thread overview]
Message-ID: <b5875cbf-16f6-41cd-1f9e-cb94b0eb3a18@redhat.com> (raw)
In-Reply-To: <CALCETrWMP9kTmAFCR0WHR3YP93gLSzgxhfnb0ma_0q=PCuSdQA@mail.gmail.com>
On 05/19/2018 03:50 AM, Andy Lutomirski wrote:
> Now another thread calls pkey_alloc(), so UAMR is asynchronously changed,
> and the thread will write zero to the relevant AMR bits. If I understand
> correctly, this means that the decision to mask off unallocated keys via
> UAMR effectively forces the initial value of newly-allocated keys in other
> threads in the allocating process to be zero, whatever zero means. (I
> didn't get far enough in the POWER docs to figure out what zero means.) So
(Note that this belongs on the other thread, here I originally wanted to
talk about the lack of reset of AMR to the default value on execve.)
I don't think UAMOR is updated asynchronously. On pkey_alloc, it is
only changed for the current thread, and future threads launched from
it. Existing threads are unaffected. This still results in a
programming model which is substantially different from x86.
> I don't think you're doing anyone any favors by making UAMR dynamic.
This is still true, I think.
Thanks,
Florian
next prev parent reply other threads:[~2018-05-19 5:26 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 14:27 pkeys on POWER: Access rights not reset on execve Florian Weimer
2018-05-19 1:19 ` Ram Pai
2018-05-19 1:50 ` Andy Lutomirski
2018-05-19 5:26 ` Florian Weimer [this message]
2018-05-19 20:27 ` Ram Pai
2018-05-19 23:47 ` Andy Lutomirski
2018-05-20 6:04 ` Ram Pai
2018-05-20 6:06 ` Andy Lutomirski
2018-05-20 19:11 ` Ram Pai
2018-05-21 11:29 ` Florian Weimer
2018-06-03 20:18 ` Ram Pai
2018-06-04 10:12 ` Florian Weimer
2018-06-04 14:01 ` Ram Pai
2018-06-04 17:57 ` Florian Weimer
2018-06-04 19:02 ` Ram Pai
2018-06-04 21:00 ` Florian Weimer
2018-06-08 2:34 ` Ram Pai
2018-06-08 5:53 ` Florian Weimer
2018-06-08 10:15 ` Michal Suchánek
2018-06-08 10:44 ` Florian Weimer
2018-06-08 12:54 ` Michal Suchánek
2018-06-08 12:57 ` Florian Weimer
2018-06-08 13:49 ` Michal Suchánek
2018-06-08 13:51 ` Florian Weimer
2018-06-08 14:17 ` Michal Suchánek
2018-06-11 17:23 ` Ram Pai
2018-06-11 17:29 ` Florian Weimer
2018-06-11 20:08 ` Ram Pai
2018-06-12 12:17 ` Florian Weimer
2018-05-19 5:12 ` Florian Weimer
2018-05-19 11:11 ` Florian Weimer
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