linux-kernel - [PATCH 19/31] x86/insn: perf tools: Pedantically tweak opcode map for MPX instructions

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Message-Id: <1441385115-6744-20-git-send-email-acme@kernel.org>
Date:	Fri,  4 Sep 2015 13:45:03 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Adrian Hunter <adrian.hunter@...el.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andy Lutomirski <luto@...capital.net>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Jiri Olsa <jolsa@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Qiaowei Ren <qiaowei.ren@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 19/31] x86/insn: perf tools: Pedantically tweak opcode map for MPX instructions

From: Adrian Hunter <adrian.hunter@...el.com>

The MPX instructions are presently not described in the SDM
opcode maps, and there are not encoding characters for bnd
registers, address method or operand type.  So the kernel
opcode map is using 'Gv' for bnd registers and 'Ev' for
everything else.  That is fine because the instruction
decoder does not use that information anyway, except as
an indication that there is a ModR/M byte.

Nevertheless, in some cases the 'Gv' and 'Ev' are the wrong
way around, BNDLDX and BNDSTX have 2 operands not 3, and it
wouldn't hurt to identify the mandatory prefixes.

This has no effect on the decoding of valid instructions,
but the addition of the mandatory prefixes will cause some
invalid instructions to error out that wouldn't have
previously.

Note that perf tools has a copy of the instruction decoder
and provides a test for new instructions which includes MPX
instructions e.g.

  $ perf test "x86 ins"
  39: Test x86 instruction decoder - new instructions          : Ok

Or to see the details:

  $ perf test -v "x86 ins"

Commiter notes:

And to see these MPX instructions specifically:

  $ perf test -v "x86 ins" 2>&1 | grep bndldx | head -3
  Decoded ok: 0f 1a 00             	bndldx (%eax),%bnd0
  Decoded ok: 0f 1a 05 78 56 34 12 	bndldx 0x12345678,%bnd0
  Decoded ok: 0f 1a 18             	bndldx (%eax),%bnd3
  $ perf test -v "x86 ins" 2>&1 | grep bndstx | head -3
  Decoded ok: 0f 1b 00             	bndstx %bnd0,(%eax)
  Decoded ok: 0f 1b 05 78 56 34 12 	bndstx %bnd0,0x12345678
  Decoded ok: 0f 1b 18             	bndstx %bnd3,(%eax)
  $

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Qiaowei Ren <qiaowei.ren@...el.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/1441196131-20632-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 arch/x86/lib/x86-opcode-map.txt                     | 8 ++++++--
 tools/perf/util/intel-pt-decoder/x86-opcode-map.txt | 8 ++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt
index 816488c0b97e..a02a195d219c 100644
--- a/arch/x86/lib/x86-opcode-map.txt
+++ b/arch/x86/lib/x86-opcode-map.txt
@@ -353,8 +353,12 @@ AVXcode: 1
 17: vmovhps Mq,Vq (v1) | vmovhpd Mq,Vq (66),(v1)
 18: Grp16 (1A)
 19:
-1a: BNDCL Ev,Gv | BNDCU Ev,Gv | BNDMOV Gv,Ev | BNDLDX Gv,Ev,Gv
-1b: BNDCN Ev,Gv | BNDMOV Ev,Gv | BNDMK Gv,Ev | BNDSTX Ev,GV,Gv
+# Intel SDM opcode map does not list MPX instructions. For now using Gv for
+# bnd registers and Ev for everything else is OK because the instruction
+# decoder does not use the information except as an indication that there is
+# a ModR/M byte.
+1a: BNDCL Gv,Ev (F3) | BNDCU Gv,Ev (F2) | BNDMOV Gv,Ev (66) | BNDLDX Gv,Ev
+1b: BNDCN Gv,Ev (F2) | BNDMOV Ev,Gv (66) | BNDMK Gv,Ev (F3) | BNDSTX Ev,Gv
 1c:
 1d:
 1e:
diff --git a/tools/perf/util/intel-pt-decoder/x86-opcode-map.txt b/tools/perf/util/intel-pt-decoder/x86-opcode-map.txt
index 816488c0b97e..a02a195d219c 100644
--- a/tools/perf/util/intel-pt-decoder/x86-opcode-map.txt
+++ b/tools/perf/util/intel-pt-decoder/x86-opcode-map.txt
@@ -353,8 +353,12 @@ AVXcode: 1
 17: vmovhps Mq,Vq (v1) | vmovhpd Mq,Vq (66),(v1)
 18: Grp16 (1A)
 19:
-1a: BNDCL Ev,Gv | BNDCU Ev,Gv | BNDMOV Gv,Ev | BNDLDX Gv,Ev,Gv
-1b: BNDCN Ev,Gv | BNDMOV Ev,Gv | BNDMK Gv,Ev | BNDSTX Ev,GV,Gv
+# Intel SDM opcode map does not list MPX instructions. For now using Gv for
+# bnd registers and Ev for everything else is OK because the instruction
+# decoder does not use the information except as an indication that there is
+# a ModR/M byte.
+1a: BNDCL Gv,Ev (F3) | BNDCU Gv,Ev (F2) | BNDMOV Gv,Ev (66) | BNDLDX Gv,Ev
+1b: BNDCN Gv,Ev (F2) | BNDMOV Ev,Gv (66) | BNDMK Gv,Ev (F3) | BNDSTX Ev,Gv
 1c:
 1d:
 1e:
-- 
2.1.0

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