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@devno... 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 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