linux-kernel - [PATCH AUTOSEL 4.9 110/141] x86/decoder: Add TEST opcode to Group3-2

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Message-Id: <20200214162122.19794-110-sashal@kernel.org>
Date:   Fri, 14 Feb 2020 11:20:50 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        Borislav Petkov <bp@...e.de>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.9 110/141] x86/decoder: Add TEST opcode to Group3-2

From: Masami Hiramatsu <mhiramat@...nel.org>

[ Upstream commit 8b7e20a7ba54836076ff35a28349dabea4cec48f ]

Add TEST opcode to Group3-2 reg=001b as same as Group3-1 does.

Commit

  12a78d43de76 ("x86/decoder: Add new TEST instruction pattern")

added a TEST opcode assignment to f6 XX/001/XXX (Group 3-1), but did
not add f7 XX/001/XXX (Group 3-2).

Actually, this TEST opcode variant (ModRM.reg /1) is not described in
the Intel SDM Vol2 but in AMD64 Architecture Programmer's Manual Vol.3,
Appendix A.2 Table A-6. ModRM.reg Extensions for the Primary Opcode Map.

Without this fix, Randy found a warning by insn_decoder_test related
to this issue as below.

    HOSTCC  arch/x86/tools/insn_decoder_test
    HOSTCC  arch/x86/tools/insn_sanity
    TEST    posttest
  arch/x86/tools/insn_decoder_test: warning: Found an x86 instruction decoder bug, please report this.
  arch/x86/tools/insn_decoder_test: warning: ffffffff81000bf1:	f7 0b 00 01 08 00    	testl  $0x80100,(%rbx)
  arch/x86/tools/insn_decoder_test: warning: objdump says 6 bytes, but insn_get_length() says 2
  arch/x86/tools/insn_decoder_test: warning: Decoded and checked 11913894 instructions with 1 failures
    TEST    posttest
  arch/x86/tools/insn_sanity: Success: decoded and checked 1000000 random instructions with 0 errors (seed:0x871ce29c)

To fix this error, add the TEST opcode according to AMD64 APM Vol.3.

 [ bp: Massage commit message. ]

Reported-by: Randy Dunlap <rdunlap@...radead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Acked-by: Randy Dunlap <rdunlap@...radead.org>
Tested-by: Randy Dunlap <rdunlap@...radead.org>
Link: https://lkml.kernel.org/r/157966631413.9580.10311036595431878351.stgit@devnote2
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/lib/x86-opcode-map.txt               | 2 +-
 tools/objtool/arch/x86/lib/x86-opcode-map.txt | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt
index 0f7eb4f5bdb71..82e105b284e01 100644
--- a/arch/x86/lib/x86-opcode-map.txt
+++ b/arch/x86/lib/x86-opcode-map.txt
@@ -909,7 +909,7 @@ EndTable
 
 GrpTable: Grp3_2
 0: TEST Ev,Iz
-1:
+1: TEST Ev,Iz
 2: NOT Ev
 3: NEG Ev
 4: MUL rAX,Ev
diff --git a/tools/objtool/arch/x86/lib/x86-opcode-map.txt b/tools/objtool/arch/x86/lib/x86-opcode-map.txt
index 0f7eb4f5bdb71..82e105b284e01 100644
--- a/tools/objtool/arch/x86/lib/x86-opcode-map.txt
+++ b/tools/objtool/arch/x86/lib/x86-opcode-map.txt
@@ -909,7 +909,7 @@ EndTable
 
 GrpTable: Grp3_2
 0: TEST Ev,Iz
-1:
+1: TEST Ev,Iz
 2: NOT Ev
 3: NEG Ev
 4: MUL rAX,Ev
-- 
2.20.1