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RE: [PATCH 0/2] Split tdesc_(amd64|i386)_mpx into tdesc(amd64|i386)_mpx_* and tdesc(amd64|i386)_avx_mpx_*
- From: "Tedeschi, Walfred" <walfred dot tedeschi at intel dot com>
- To: Marcin Koscielnicki <koriakin at 0x04 dot net>, "palves at redhat dot com" <palves at redhat dot com>, "eliz at gnu dot org" <eliz at gnu dot org>, "brobecker at adacore dot com" <brobecker at adacore dot com>
- Cc: "gdb-patches at sourceware dot org" <gdb-patches at sourceware dot org>
- Date: Wed, 2 Mar 2016 10:02:54 +0000
- Subject: RE: [PATCH 0/2] Split tdesc_(amd64|i386)_mpx into tdesc(amd64|i386)_mpx_* and tdesc(amd64|i386)_avx_mpx_*
- Authentication-results: sourceware.org; auth=none
- References: <1456130945-25045-1-git-send-email-walfred dot tedeschi at intel dot com> <56CF5430 dot 2000502 at 0x04 dot net>
-----Original Message-----
From: Marcin Kościelnicki [mailto:koriakin@0x04.net]
Sent: Thursday, February 25, 2016 8:21 PM
To: Tedeschi, Walfred; palves@redhat.com; eliz@gnu.org; brobecker@adacore.com
Cc: gdb-patches@sourceware.org
Subject: Re: [PATCH 0/2] Split tdesc_(amd64|i386)_mpx into tdesc(amd64|i386)_mpx_* and tdesc(amd64|i386)_avx_mpx_*
On 22/02/16 09:49, Walfred Tedeschi wrote:
> CPU features can occur in any combination. The current assumption that
> feature "A" implies in feature "B" does not necessarily hold.
>
> This patch series construct an additional combination of the Intel(R)
> Memory Protection Extensions (MPX) with Intel(R) Advanced Vector
> Extensions (AVX).
>
> Starting from the current implementation that has MPX combined with AVX.
> A new target description having only MPX will be created using a two
> step approach as described below:
>
> First step:
> Mirror (i386|amd64)mpx target descriptors onto (i386|amd64)-avx-mpx
> ones.
>
> Add a redundant target description for the MPX and AVX case using a
> combined feature name to reflect that, i.e. avx-mpx. A new flag 2is
> also added to address MPX case without AVX.
>
>
> Second step:
> Refactor (i386|amd64)-mpx target descriptors.
>
> AVX feature is removed from the set of files that described MPX alone
> feature. Present on GDB code previous to this patch.
>
>
> Tests were done with hardware having MPX and AVX as is.
> For MPX standing alone tests were done forcing the XCR0 bits.
>
>
FYI, I've just refactored a few things in x86 tdescs, to properly pass them into the IPA - you will have a conflict with my commit ae91f6253926e4dadebcae90772f4f5a5bd06056. You will have to add an X86_TDESC_AVX_MPX enum value, emit it in gdbserver when you're using one of the new tdescs, and recognize it in the IPAs. Sorry for the inconvenience.
Marcin,
Thanks a lot for the heads up!
I looks like it is time to refactor the tdesc_selection, or? I suppose I have seen this code now 5 times.
May I do it and send as a separated patch?
Thanks and regards,
-Fred
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