[adding x86 people] I am still seeing this insn_decoder warning in linux-next. Can we get this patch applied, please? Masami, you might need to resend it... thanks. On 11/27/19 4:04 PM, Randy Dunlap wrote: > 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 Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
