[PATCH 4.14 138/237] x86/decoder: Add TEST opcode to Group3-2

Greg Kroah-Hartman
2020-02-27T14:37:04Z

From: Masami Hiramatsu <mhiramat@kernel.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@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>
---
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 0a0e9112f2842..5cb9f009f2be3 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 0a0e9112f2842..5cb9f009f2be3 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