x86/decoder: Add TEST opcode to Group3-2
[ 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@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: Sasha Levin <sashal@kernel.org>
2 files changed