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x86/decoder: Add TEST opcode to Group3-2
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Add TEST opcode to Group3-2 reg=001b as same as Group3-1 does.

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  12a78d4 ("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
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Masami Hiramatsu authored and Borislav Petkov committed Jan 22, 2020
1 parent def9d27 commit 8b7e20a
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Showing 2 changed files with 2 additions and 2 deletions.
2 changes: 1 addition & 1 deletion arch/x86/lib/x86-opcode-map.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -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
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2 changes: 1 addition & 1 deletion tools/arch/x86/lib/x86-opcode-map.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -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
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