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From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 08/10] x86, mpx: add prctl commands PR_MPX_REGISTER, PR_MPX_UNREGISTER
Date: Fri, 12 Sep 2014 20:42:23 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.10.1409122038590.4178@nanos> (raw)
In-Reply-To: <alpine.DEB.2.10.1409121812550.4178@nanos>

On Fri, 12 Sep 2014, Thomas Gleixner wrote:
> On Fri, 12 Sep 2014, Dave Hansen wrote:
> The proper solution to this problem is:
> 
>     do_bounds()
> 	bd_addr = get_bd_addr_from_xsave();
> 	bd_entry = bndstatus & ADDR_MASK:

Just for clarification. You CANNOT avoid the xsave here because it's
the only way to access BNDSTATUS according to the manual.

"The BNDCFGU and BNDSTATUS registers are accessible only with
 XSAVE/XRSTOR family of instructions"

So there is no point to cache BNDCFGU as you get it anyway when you
need to retrieve the invalid BD entry.

Thanks,

	tglx

WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 08/10] x86, mpx: add prctl commands PR_MPX_REGISTER, PR_MPX_UNREGISTER
Date: Fri, 12 Sep 2014 20:42:23 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.10.1409122038590.4178@nanos> (raw)
In-Reply-To: <alpine.DEB.2.10.1409121812550.4178@nanos>

On Fri, 12 Sep 2014, Thomas Gleixner wrote:
> On Fri, 12 Sep 2014, Dave Hansen wrote:
> The proper solution to this problem is:
> 
>     do_bounds()
> 	bd_addr = get_bd_addr_from_xsave();
> 	bd_entry = bndstatus & ADDR_MASK:

Just for clarification. You CANNOT avoid the xsave here because it's
the only way to access BNDSTATUS according to the manual.

"The BNDCFGU and BNDSTATUS registers are accessible only with
 XSAVE/XRSTOR family of instructions"

So there is no point to cache BNDCFGU as you get it anyway when you
need to retrieve the invalid BD entry.

Thanks,

	tglx

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  reply	other threads:[~2014-09-12 18:42 UTC|newest]

Thread overview: 130+ 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 ` 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   ` 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   ` 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   ` Qiaowei Ren
2014-09-11  8:46 ` [PATCH v8 04/10] x86, mpx: hook #BR exception handler to allocate bound tables Qiaowei Ren
2014-09-11  8:46   ` Qiaowei Ren
2014-09-12 22:58   ` Dave Hansen
2014-09-12 22:58     ` Dave Hansen
2014-09-13  7:24     ` Ren, Qiaowei
2014-09-13  7:24       ` Ren, Qiaowei
2014-09-24 14:40   ` Dave Hansen
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   ` Qiaowei Ren
2014-09-11  8:46 ` [PATCH v8 06/10] mips: sync struct siginfo with general version Qiaowei Ren
2014-09-11  8:46   ` Qiaowei Ren
2014-09-11 22:13   ` Thomas Gleixner
2014-09-11 22:13     ` Thomas Gleixner
2014-09-12  2:54     ` Ren, Qiaowei
2014-09-12  2:54       ` Ren, Qiaowei
2014-09-12  8:17       ` Thomas Gleixner
2014-09-12  8:17         ` Thomas Gleixner
2014-09-13  7:13         ` Ren, Qiaowei
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  8:46   ` Qiaowei Ren
2014-09-11 22:18   ` Thomas Gleixner
2014-09-11 22:18     ` Thomas Gleixner
2014-09-11 22:32     ` Dave Hansen
2014-09-11 22:32       ` Dave Hansen
2014-09-11 22:35       ` H. Peter Anvin
2014-09-11 22:35         ` H. Peter Anvin
2014-09-11 23:37         ` Thomas Gleixner
2014-09-11 23:37           ` Thomas Gleixner
2014-09-12  4:44           ` H. Peter Anvin
2014-09-12  4:44             ` H. Peter Anvin
2014-09-12 13:10             ` Thomas Gleixner
2014-09-12 13:10               ` Thomas Gleixner
2014-09-12 13:39               ` H. Peter Anvin
2014-09-12 13:39                 ` H. Peter Anvin
2014-09-12 17:48                 ` Thomas Gleixner
2014-09-12 17:48                   ` Thomas Gleixner
2014-09-12 17:52         ` Thomas Gleixner
2014-09-12 17:52           ` Thomas Gleixner
2014-09-12 19:07           ` H. Peter Anvin
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  8:46   ` Qiaowei Ren
2014-09-11 15:03   ` Dave Hansen
2014-09-11 15:03     ` Dave Hansen
2014-09-12  3:10     ` Ren, Qiaowei
2014-09-12  3:10       ` Ren, Qiaowei
2014-09-11 23:28   ` Thomas Gleixner
2014-09-11 23:28     ` Thomas Gleixner
2014-09-12  0:10     ` Dave Hansen
2014-09-12  0:10       ` Dave Hansen
2014-09-12  8:11       ` Thomas Gleixner
2014-09-12  8:11         ` Thomas Gleixner
2014-09-12  9:24         ` Thomas Gleixner
2014-09-12  9:24           ` Thomas Gleixner
2014-09-12 14:36           ` Dave Hansen
2014-09-12 14:36             ` Dave Hansen
2014-09-12 17:34             ` Thomas Gleixner
2014-09-12 17:34               ` Thomas Gleixner
2014-09-12 18:42               ` Thomas Gleixner [this message]
2014-09-12 18:42                 ` Thomas Gleixner
2014-09-12 20:35                 ` Dave Hansen
2014-09-12 20:35                   ` Dave Hansen
2014-09-12 20:18               ` Dave Hansen
2014-09-12 20:18                 ` Dave Hansen
2014-09-13  9:01                 ` Thomas Gleixner
2014-09-13  9:01                   ` Thomas Gleixner
2014-09-12 15:22         ` Dave Hansen
2014-09-12 15:22           ` Dave Hansen
2014-09-12 17:42           ` Thomas Gleixner
2014-09-12 17:42             ` Thomas Gleixner
2014-09-12 20:33             ` Dave Hansen
2014-09-12 20:33               ` Dave Hansen
2014-09-15  0:00   ` One Thousand Gnomes
2014-09-15  0:00     ` One Thousand Gnomes
2014-09-16  3:20     ` Ren, Qiaowei
2014-09-16  3:20       ` Ren, Qiaowei
2014-09-16  4:17       ` Dave Hansen
2014-09-16  4:17         ` Dave Hansen
2014-09-16  7:50   ` Kevin Easton
2014-09-16  7:50     ` Kevin Easton
2014-09-18  0:40     ` Ren, Qiaowei
2014-09-18  0:40       ` Ren, Qiaowei
2014-09-18  3:23       ` Kevin Easton
2014-09-18  3:23         ` Kevin Easton
2014-09-18  2:37         ` Ren, Qiaowei
2014-09-18  2:37           ` Ren, Qiaowei
2014-09-18  4:43         ` Dave Hansen
2014-09-18  4:43           ` Dave Hansen
2014-09-18  7:17           ` Kevin Easton
2014-09-18  7:17             ` Kevin Easton
2014-09-18  6:20             ` Dave Hansen
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  8:46   ` Qiaowei Ren
2014-09-11 14:59   ` Dave Hansen
2014-09-11 14:59     ` Dave Hansen
2014-09-12  3:02     ` Ren, Qiaowei
2014-09-12  3:02       ` Ren, Qiaowei
2014-09-12  4:59       ` Dave Hansen
2014-09-12  4:59         ` Dave Hansen
2014-09-15 20:53   ` Dave Hansen
2014-09-15 20:53     ` Dave Hansen
2014-09-16  8:06     ` Ren, Qiaowei
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
2014-09-11  8:46   ` Qiaowei Ren
2014-09-12  0:51 ` [PATCH v8 00/10] Intel MPX support Dave Hansen
2014-09-12  0:51   ` Dave Hansen
2014-09-12 19:21   ` Thomas Gleixner
2014-09-12 19:21     ` Thomas Gleixner
2014-09-12 21:23     ` Dave Hansen
2014-09-12 21:23       ` Dave Hansen
2014-09-13  9:25       ` Thomas Gleixner
2014-09-13  9:25         ` Thomas Gleixner
2014-09-12 21:31     ` Dave Hansen
2014-09-12 21:31       ` Dave Hansen
2014-09-12 22:08     ` Dave Hansen
2014-09-12 22:08       ` Dave Hansen
2014-09-13  9:39       ` Thomas Gleixner
2014-09-13  9:39         ` Thomas Gleixner

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