Messages in this thread | | | Date | Fri, 12 Sep 2014 19:52:37 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v8 07/10] x86, mpx: decode MPX instruction to get bound violation information |
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On Thu, 11 Sep 2014, H. Peter Anvin wrote:
> On 09/11/2014 03:32 PM, Dave Hansen wrote: > > On 09/11/2014 03:18 PM, Thomas Gleixner wrote: > >> On Thu, 11 Sep 2014, Qiaowei Ren wrote: > >>> This patch sets bound violation fields of siginfo struct in #BR > >>> exception handler by decoding the user instruction and constructing > >>> the faulting pointer. > >>> > >>> This patch does't use the generic decoder, and implements a limited > >>> special-purpose decoder to decode MPX instructions, simply because the > >>> generic decoder is very heavyweight not just in terms of performance > >>> but in terms of interface -- because it has to. > >> > >> And why is that an argument to add another special purpose decoder? > > > > Peter asked for it to be done this way specifically: > > > > https://lkml.org/lkml/2014/6/19/411 > > > > Specifically because marshaling the data in and out of the generic > decoder was more complex than a special-purpose decoder.
Well, I did not see the trainwreck which tried to use the generic decoder, but as I explained in the other mail, there is no reason not to use it and I can't see any complexity in retrieving the data beyond calling insn_get_length(insn);
Thanks,
tglx
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