On 10/22/19 10:49 PM, Masami Hiramatsu wrote: > Hi, > > On Mon, 14 Oct 2019 08:30:02 -0700 > Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: > >> On 10/13/19 11:47 PM, Stephen Rothwell wrote: >>> Hi all, >>> >>> Changes since 20191011: >>> >> >> on x86_64: >> >> 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) > > Hmm, curious. > > x86-opcode-map.txt said, > f7: Grp3_2 Ev (1A) > > and "0x0b" is 00001011b, Group encoding bits are 5,4,3 (reg field), > so group index is 001. > > GrpTable: Grp3_2 > 0: TEST Ev,Iz > 1: > > Hmm, "f7 0b" is not assigned to any instruction... (testl should be f7 03) > > I've checked Intel SDM May 2019 version(*), but the Opcode Map (Table A-6. Opecode > Extensions for One- and Two-byte Opecodes by Group Number) showed the group index > 001 is still blank. I've also checked that Table B-13 (General Purpose Instruction > Formats and Encodings for Non-64-Bit Modes (Note that this has no REX prefix)) but > I couldn't find "f7 0b". > > At last, I found that on AMD64 Architecture Programmer's Manual Volume 3, Appendix A.2 > Table A-6. ModRM.reg Extensions for the Primary Opcode Map(**), which shows that both > f7 + reg=000 and f7 + reg=001 are same. So only on AMD64, it is officially available > instruction. > > (*) https://software.intel.com/sites/default/files/managed/a4/60/325383-sdm-vol-2abcd.pdf > (**) https://www.amd.com/system/files/TechDocs/24594.pdf > > OK, so this should be fixed with below patch. > > ------ >>From b3f45b86df25be59fcf417730ab4c69c6310eaad Mon Sep 17 00:00:00 2001 > From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > Date: Wed, 23 Oct 2019 14:45:35 +0900 > Subject: [PATCH] x86/decoder: Add TEST opcode to Group3-2 > > 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 not > added f7 XX/001/XXX (Group 3-2). Actually these TEST opcode is not > described in Intel SDM Vol2, but described 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 TEST opcode according to AMD64 APM Vol.3. > > Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Thanks. > --- > arch/x86/lib/x86-opcode-map.txt | 2 +- > tools/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 e0b85930dd77..4635ce298d1d 100644 > --- a/arch/x86/lib/x86-opcode-map.txt > +++ b/arch/x86/lib/x86-opcode-map.txt > @@ -907,7 +907,7 @@ 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/arch/x86/lib/x86-opcode-map.txt b/tools/arch/x86/lib/x86-opcode-map.txt > index e0b85930dd77..4635ce298d1d 100644 > --- a/tools/arch/x86/lib/x86-opcode-map.txt > +++ b/tools/arch/x86/lib/x86-opcode-map.txt > @@ -907,7 +907,7 @@ EndTable > > GrpTable: Grp3_2 > 0: TEST Ev,Iz > -1: > +1: TEST Ev,Iz > 2: NOT Ev > 3: NEG Ev > 4: MUL rAX,Ev > -- ~Randy
