diff options
| author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-11-24 13:56:30 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-11-24 08:36:12 +0100 |
| commit | 12a78d43de767eaf8fb272facb7a7b6f2dc6a9df (patch) | |
| tree | 12c3c4cd7829cf5a8bb1dabd5262366ba7164996 | |
| parent | fd2fa6c18b729e19c51240453a521f76c766247e (diff) | |
| download | lwn-12a78d43de767eaf8fb272facb7a7b6f2dc6a9df.tar.gz lwn-12a78d43de767eaf8fb272facb7a7b6f2dc6a9df.zip | |
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.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/lib/x86-opcode-map.txt | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt index 12e377184ee4..c4d55919fac1 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 |