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From: Dave Hansen <dave.hansen@intel.com>
To: Kevin Easton <kevin@guarana.org>, "Ren, Qiaowei" <qiaowei.ren@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "x86@kernel.org" <x86@kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v8 08/10] x86, mpx: add prctl commands PR_MPX_REGISTER, PR_MPX_UNREGISTER
Date: Wed, 17 Sep 2014 21:43:09 -0700	[thread overview]
Message-ID: <541A62DD.7080502@intel.com> (raw)
In-Reply-To: <20140918032334.GA26560@chicago.guarana.org>

On 09/17/2014 08:23 PM, Kevin Easton wrote:
> I was actually thinking that the kernel would take care of the xsave / 
> xrstor (for current), updating tsk->thread.fpu.state (for non-running
> threads) and sending an IPI for threads running on other CPUs.
> 
> Of course userspace can always then manually change the bounds directory
> address itself, but then it's quite clear that they're doing something
> unsupported.  Just an idea, anyway.

What's the benefit of that?

As it stands now, MPX is likely to be enabled well before any threads
are created, and the MPX enabling state will be inherited by the new
thread at clone() time.  The current mechanism allows a thread to
individually enable or disable MPX independently of the other threads.

I think it makes it both more complicated and less flexible.

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  parent reply	other threads:[~2014-09-18  4:43 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-11  8:46 [PATCH v8 00/10] Intel MPX support Qiaowei Ren
2014-09-11  8:46 ` [PATCH v8 01/10] x86, mpx: introduce VM_MPX to indicate that a VMA is MPX specific Qiaowei Ren
2014-09-11  8:46 ` [PATCH v8 02/10] x86, mpx: add MPX specific mmap interface Qiaowei Ren
2014-09-11  8:46 ` [PATCH v8 03/10] x86, mpx: add macro cpu_has_mpx Qiaowei Ren
2014-09-11  8:46 ` [PATCH v8 04/10] x86, mpx: hook #BR exception handler to allocate bound tables Qiaowei Ren
2014-09-12 22:58   ` Dave Hansen
2014-09-13  7:24     ` Ren, Qiaowei
2014-09-24 14:40   ` Dave Hansen
2014-09-11  8:46 ` [PATCH v8 05/10] x86, mpx: extend siginfo structure to include bound violation information Qiaowei Ren
2014-09-11  8:46 ` [PATCH v8 06/10] mips: sync struct siginfo with general version Qiaowei Ren
2014-09-11 22:13   ` Thomas Gleixner
2014-09-12  2:54     ` Ren, Qiaowei
2014-09-12  8:17       ` Thomas Gleixner
2014-09-13  7:13         ` Ren, Qiaowei
2014-09-11  8:46 ` [PATCH v8 07/10] x86, mpx: decode MPX instruction to get bound violation information Qiaowei Ren
2014-09-11 22:18   ` Thomas Gleixner
2014-09-11 22:32     ` Dave Hansen
2014-09-11 22:35       ` H. Peter Anvin
2014-09-11 23:37         ` Thomas Gleixner
2014-09-12  4:44           ` H. Peter Anvin
2014-09-12 13:10             ` Thomas Gleixner
2014-09-12 13:39               ` H. Peter Anvin
2014-09-12 17:48                 ` Thomas Gleixner
2014-09-12 17:52         ` Thomas Gleixner
2014-09-12 19:07           ` H. Peter Anvin
2014-09-11  8:46 ` [PATCH v8 08/10] x86, mpx: add prctl commands PR_MPX_REGISTER, PR_MPX_UNREGISTER Qiaowei Ren
2014-09-11 15:03   ` Dave Hansen
2014-09-12  3:10     ` Ren, Qiaowei
2014-09-11 23:28   ` Thomas Gleixner
2014-09-12  0:10     ` Dave Hansen
2014-09-12  8:11       ` Thomas Gleixner
2014-09-12  9:24         ` Thomas Gleixner
2014-09-12 14:36           ` Dave Hansen
2014-09-12 17:34             ` Thomas Gleixner
2014-09-12 18:42               ` Thomas Gleixner
2014-09-12 20:35                 ` Dave Hansen
2014-09-12 20:18               ` Dave Hansen
2014-09-13  9:01                 ` Thomas Gleixner
2014-09-12 15:22         ` Dave Hansen
2014-09-12 17:42           ` Thomas Gleixner
2014-09-12 20:33             ` Dave Hansen
2014-09-15  0:00   ` One Thousand Gnomes
2014-09-16  3:20     ` Ren, Qiaowei
2014-09-16  4:17       ` Dave Hansen
2014-09-16  7:50   ` Kevin Easton
2014-09-18  0:40     ` Ren, Qiaowei
2014-09-18  3:23       ` Kevin Easton
2014-09-18  2:37         ` Ren, Qiaowei
2014-09-18  4:43         ` Dave Hansen [this message]
2014-09-18  7:17           ` Kevin Easton
2014-09-18  6:20             ` Dave Hansen
2014-09-11  8:46 ` [PATCH v8 09/10] x86, mpx: cleanup unused bound tables Qiaowei Ren
2014-09-11 14:59   ` Dave Hansen
2014-09-12  3:02     ` Ren, Qiaowei
2014-09-12  4:59       ` Dave Hansen
2014-09-15 20:53   ` Dave Hansen
2014-09-16  8:06     ` Ren, Qiaowei
2014-09-11  8:46 ` [PATCH v8 10/10] x86, mpx: add documentation on Intel MPX Qiaowei Ren
2014-09-12  0:51 ` [PATCH v8 00/10] Intel MPX support Dave Hansen
2014-09-12 19:21   ` Thomas Gleixner
2014-09-12 21:23     ` Dave Hansen
2014-09-13  9:25       ` Thomas Gleixner
2014-09-12 21:31     ` Dave Hansen
2014-09-12 22:08     ` Dave Hansen
2014-09-13  9:39       ` Thomas Gleixner

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