From: Thomas Gleixner <tglx@linutronix.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
Qiaowei Ren <qiaowei.ren@intel.com>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 07/10] x86, mpx: decode MPX instruction to get bound violation information
Date: Fri, 12 Sep 2014 19:48:27 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.10.1409121943430.4178@nanos> (raw)
In-Reply-To: <5412F7AB.5040901@zytor.com>
On Fri, 12 Sep 2014, H. Peter Anvin wrote:
> The correct limit is 15 bytes, not anything else, so this is a bug in
> the existing decoder. A sequence of bytes longer than 15 bytes will
Fine. Lets fix it there.
> #UD, regardless of being "otherwise valid".
> Keep in mind the instruction may not be aligned, and you could fit an
> instruction plus a jump and still overrun a page in 15 bytes.
Fair enough. OTOH, I doubt that a text mapping will end exactly at
that jump after the MPX instruction.
So that's simple to fix.
Kill the hardcoded limit in lib/insn.c and let the callsites hand in a
lenght argument. So you can still use it for MPX and avoid 200 lines
of blindly copied and slightly different decoder code.
Thanks,
tglx
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next prev parent reply other threads:[~2014-09-12 17:48 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 [this message]
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
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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