Commit-ID: 843c885f41b3c74212d8a85da95993075dd41415 Gitweb: https://git.kernel.org/tip/843c885f41b3c74212d8a85da95993075dd41415 Author: Masami Hiramatsu <mhiramat@xxxxxxxxxx> AuthorDate: Fri, 24 Nov 2017 13:56:30 +0900 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Fri, 24 Nov 2017 08:16:09 +0100 x86/decoder: Add new TEST instruction pattern The kbuild test robot reported this build warning: Warning: arch/x86/tools/test_get_len found difference at <jump_table>:ffffffff8103dd2c Warning: ffffffff8103dd82: f6 09 d8 testb $0xd8,(%rcx) Warning: objdump says 3 bytes, but insn_get_length() says 2 Warning: decoded and checked 1569014 instructions with 1 warnings This sequence seems to be a new instruction not in the opcode map in the Intel SDM. The instruction sequence is "F6 09 d8", means Group3(F6), MOD(00)REG(001)RM(001), and 0xd8. Intel SDM vol2 A.4 Table A-6 said the table index in the group is "Encoding of Bits 5,4,3 of the ModR/M Byte (bits 2,1,0 in parenthesis)" In that table, opcodes listed by the index REG bits as: 000 001 010 011 100 101 110 111 TEST Ib/Iz,(undefined),NOT,NEG,MUL AL/rAX,IMUL AL/rAX,DIV AL/rAX,IDIV AL/rAX So, it seems TEST Ib is assigned to 001. Add the new pattern. Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/lib/x86-opcode-map.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt index 12e3771..c4d5591 100644 --- a/arch/x86/lib/x86-opcode-map.txt +++ b/arch/x86/lib/x86-opcode-map.txt @@ -896,7 +896,7 @@ EndTable GrpTable: Grp3_1 0: TEST Eb,Ib -1: +1: TEST Eb,Ib 2: NOT Eb 3: NEG Eb 4: MUL AL,Eb