From 1756a4f78b76812a6284086b2afee830650f7784 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 22 Jan 2020 13:11:54 +0900 Subject: [PATCH] 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 Signed-off-by: Masami Hiramatsu Signed-off-by: Borislav Petkov Acked-by: Randy Dunlap Tested-by: Randy Dunlap Link: https://lkml.kernel.org/r/157966631413.9580.10311036595431878351.stgit@devnote2 Signed-off-by: Sasha Levin --- 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 0f7eb4f..82e105b 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 0f7eb4f..82e105b 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 -- 2.7.4