From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Wed, 22 Jan 2020 13:11:54 +0900
Subject: x86/decoder: Add TEST opcode to Group3-2
Git-commit: 8b7e20a7ba54836076ff35a28349dabea4cec48f
Patch-mainline: 5.6-rc1
References: git-fixes

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@infradead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lkml.kernel.org/r/157966631413.9580.10311036595431878351.stgit@devnote2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 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(-)

--- a/arch/x86/lib/x86-opcode-map.txt
+++ b/arch/x86/lib/x86-opcode-map.txt
@@ -929,7 +929,7 @@ EndTable
 
 GrpTable: Grp3_2
 0: TEST Ev,Iz
-1:
+1: TEST Ev,Iz
 2: NOT Ev
 3: NEG Ev
 4: MUL rAX,Ev
--- a/tools/objtool/arch/x86/lib/x86-opcode-map.txt
+++ b/tools/objtool/arch/x86/lib/x86-opcode-map.txt
@@ -929,7 +929,7 @@ EndTable
 
 GrpTable: Grp3_2
 0: TEST Ev,Iz
-1:
+1: TEST Ev,Iz
 2: NOT Ev
 3: NEG Ev
 4: MUL rAX,Ev