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    SubjectRe: [PATCH v8 27/27] x86/cet/shstk: Add Shadow Stack instructions to opcode map
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    On 13/08/19 11:52 PM, Yu-cheng Yu wrote:
    > Add the following shadow stack management instructions.
    >
    > INCSSP:
    > Increment shadow stack pointer by the steps specified.
    >
    > RDSSP:
    > Read SSP register into a GPR.
    >
    > SAVEPREVSSP:
    > Use "prev ssp" token at top of current shadow stack to
    > create a "restore token" on previous shadow stack.
    >
    > RSTORSSP:
    > Restore from a "restore token" pointed by a GPR to SSP.
    >
    > WRSS:
    > Write to kernel-mode shadow stack (kernel-mode instruction).
    >
    > WRUSS:
    > Write to user-mode shadow stack (kernel-mode instruction).
    >
    > SETSSBSY:
    > Verify the "supervisor token" pointed by IA32_PL0_SSP MSR,
    > if valid, set the token to busy, and set SSP to the value
    > of IA32_PL0_SSP MSR.
    >
    > CLRSSBSY:
    > Verify the "supervisor token" pointed by a GPR, if valid,
    > clear the busy bit from the token.
    >
    > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
    > ---
    > arch/x86/lib/x86-opcode-map.txt | 26 +++++++++++++------
    > tools/objtool/arch/x86/lib/x86-opcode-map.txt | 26 +++++++++++++------
    > 2 files changed, 36 insertions(+), 16 deletions(-)
    >
    > diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt
    > index e0b85930dd77..c5e825d44766 100644
    > --- a/arch/x86/lib/x86-opcode-map.txt
    > +++ b/arch/x86/lib/x86-opcode-map.txt
    > @@ -366,7 +366,7 @@ AVXcode: 1
    > 1b: BNDCN Gv,Ev (F2) | BNDMOV Ev,Gv (66) | BNDMK Gv,Ev (F3) | BNDSTX Ev,Gv
    > 1c:
    > 1d:
    > -1e:
    > +1e: RDSSP Rd (F3),REX.W
    > 1f: NOP Ev
    > # 0x0f 0x20-0x2f
    > 20: MOV Rd,Cd
    > @@ -610,7 +610,17 @@ fe: paddd Pq,Qq | vpaddd Vx,Hx,Wx (66),(v1)
    > ff: UD0
    > EndTable
    >
    > -Table: 3-byte opcode 1 (0x0f 0x38)
    > +Table: 3-byte opcode 1 (0x0f 0x01)
    > +Referrer:
    > +AVXcode:
    > +# Skip 0x00-0xe7
    > +e8: SETSSBSY (f3)
    > +e9:
    > +ea: SAVEPREVSSP (f3)
    > +# Skip 0xeb-0xff
    > +EndTable
    > +
    > +Table: 3-byte opcode 2 (0x0f 0x38)
    > Referrer: 3-byte escape 1
    > AVXcode: 2
    > # 0x0f 0x38 0x00-0x0f
    > @@ -789,12 +799,12 @@ f0: MOVBE Gy,My | MOVBE Gw,Mw (66) | CRC32 Gd,Eb (F2) | CRC32 Gd,Eb (66&F2)
    > f1: MOVBE My,Gy | MOVBE Mw,Gw (66) | CRC32 Gd,Ey (F2) | CRC32 Gd,Ew (66&F2)
    > f2: ANDN Gy,By,Ey (v)
    > f3: Grp17 (1A)
    > -f5: BZHI Gy,Ey,By (v) | PEXT Gy,By,Ey (F3),(v) | PDEP Gy,By,Ey (F2),(v)
    > -f6: ADCX Gy,Ey (66) | ADOX Gy,Ey (F3) | MULX By,Gy,rDX,Ey (F2),(v)
    > +f5: BZHI Gy,Ey,By (v) | PEXT Gy,By,Ey (F3),(v) | PDEP Gy,By,Ey (F2),(v) | WRUSS Pq,Qq (66),REX.W
    > +f6: ADCX Gy,Ey (66) | ADOX Gy,Ey (F3) | MULX By,Gy,rDX,Ey (F2),(v) | WRSS Pq,Qq (66),REX.W
    > f7: BEXTR Gy,Ey,By (v) | SHLX Gy,Ey,By (66),(v) | SARX Gy,Ey,By (F3),(v) | SHRX Gy,Ey,By (F2),(v)
    > EndTable
    >
    > -Table: 3-byte opcode 2 (0x0f 0x3a)
    > +Table: 3-byte opcode 3 (0x0f 0x3a)
    > Referrer: 3-byte escape 2
    > AVXcode: 3
    > # 0x0f 0x3a 0x00-0xff
    > @@ -948,7 +958,7 @@ GrpTable: Grp7
    > 2: LGDT Ms | XGETBV (000),(11B) | XSETBV (001),(11B) | VMFUNC (100),(11B) | XEND (101)(11B) | XTEST (110)(11B)
    > 3: LIDT Ms
    > 4: SMSW Mw/Rv
    > -5: rdpkru (110),(11B) | wrpkru (111),(11B)
    > +5: rdpkru (110),(11B) | wrpkru (111),(11B) | RSTORSSP Mq (F3)
    > 6: LMSW Ew
    > 7: INVLPG Mb | SWAPGS (o64),(000),(11B) | RDTSCP (001),(11B)
    > EndTable
    > @@ -1019,8 +1029,8 @@ GrpTable: Grp15
    > 2: vldmxcsr Md (v1) | WRFSBASE Ry (F3),(11B)
    > 3: vstmxcsr Md (v1) | WRGSBASE Ry (F3),(11B)
    > 4: XSAVE | ptwrite Ey (F3),(11B)
    > -5: XRSTOR | lfence (11B)
    > -6: XSAVEOPT | clwb (66) | mfence (11B)
    > +5: XRSTOR | lfence (11B) | INCSSP Rd (F3),REX.W
    > +6: XSAVEOPT | clwb (66) | mfence (11B) | CLRSSBSY Mq (F3)
    > 7: clflush | clflushopt (66) | sfence (11B)
    > EndTable
    >
    > diff --git a/tools/objtool/arch/x86/lib/x86-opcode-map.txt b/tools/objtool/arch/x86/lib/x86-opcode-map.txt
    > index e0b85930dd77..c5e825d44766 100644
    > --- a/tools/objtool/arch/x86/lib/x86-opcode-map.txt
    > +++ b/tools/objtool/arch/x86/lib/x86-opcode-map.txt
    > @@ -366,7 +366,7 @@ AVXcode: 1
    > 1b: BNDCN Gv,Ev (F2) | BNDMOV Ev,Gv (66) | BNDMK Gv,Ev (F3) | BNDSTX Ev,Gv
    > 1c:
    > 1d:
    > -1e:
    > +1e: RDSSP Rd (F3),REX.W

    RDSSP is in a Grp with ENDBR32 and ENDBR64

    > 1f: NOP Ev
    > # 0x0f 0x20-0x2f
    > 20: MOV Rd,Cd
    > @@ -610,7 +610,17 @@ fe: paddd Pq,Qq | vpaddd Vx,Hx,Wx (66),(v1)
    > ff: UD0
    > EndTable
    >
    > -Table: 3-byte opcode 1 (0x0f 0x38)
    > +Table: 3-byte opcode 1 (0x0f 0x01)
    > +Referrer:
    > +AVXcode:
    > +# Skip 0x00-0xe7
    > +e8: SETSSBSY (f3)
    > +e9:
    > +ea: SAVEPREVSSP (f3)

    SETSSBSY and SAVEPREVSSP should be in Grp7

    > +# Skip 0xeb-0xff
    > +EndTable
    > +
    > +Table: 3-byte opcode 2 (0x0f 0x38)
    > Referrer: 3-byte escape 1
    > AVXcode: 2
    > # 0x0f 0x38 0x00-0x0f
    > @@ -789,12 +799,12 @@ f0: MOVBE Gy,My | MOVBE Gw,Mw (66) | CRC32 Gd,Eb (F2) | CRC32 Gd,Eb (66&F2)
    > f1: MOVBE My,Gy | MOVBE Mw,Gw (66) | CRC32 Gd,Ey (F2) | CRC32 Gd,Ew (66&F2)
    > f2: ANDN Gy,By,Ey (v)
    > f3: Grp17 (1A)
    > -f5: BZHI Gy,Ey,By (v) | PEXT Gy,By,Ey (F3),(v) | PDEP Gy,By,Ey (F2),(v)
    > -f6: ADCX Gy,Ey (66) | ADOX Gy,Ey (F3) | MULX By,Gy,rDX,Ey (F2),(v)
    > +f5: BZHI Gy,Ey,By (v) | PEXT Gy,By,Ey (F3),(v) | PDEP Gy,By,Ey (F2),(v) | WRUSS Pq,Qq (66),REX.W
    > +f6: ADCX Gy,Ey (66) | ADOX Gy,Ey (F3) | MULX By,Gy,rDX,Ey (F2),(v) | WRSS Pq,Qq (66),REX.W

    I know already commented on this, but WRSS does not have (66) prefix

    Also no other instructions have been annotated with REX.W so maybe omit that

    > f7: BEXTR Gy,Ey,By (v) | SHLX Gy,Ey,By (66),(v) | SARX Gy,Ey,By (F3),(v) | SHRX Gy,Ey,By (F2),(v)
    > EndTable
    >
    > -Table: 3-byte opcode 2 (0x0f 0x3a)
    > +Table: 3-byte opcode 3 (0x0f 0x3a)
    > Referrer: 3-byte escape 2
    > AVXcode: 3
    > # 0x0f 0x3a 0x00-0xff
    > @@ -948,7 +958,7 @@ GrpTable: Grp7
    > 2: LGDT Ms | XGETBV (000),(11B) | XSETBV (001),(11B) | VMFUNC (100),(11B) | XEND (101)(11B) | XTEST (110)(11B)
    > 3: LIDT Ms
    > 4: SMSW Mw/Rv
    > -5: rdpkru (110),(11B) | wrpkru (111),(11B)
    > +5: rdpkru (110),(11B) | wrpkru (111),(11B) | RSTORSSP Mq (F3)
    > 6: LMSW Ew
    > 7: INVLPG Mb | SWAPGS (o64),(000),(11B) | RDTSCP (001),(11B)
    > EndTable
    > @@ -1019,8 +1029,8 @@ GrpTable: Grp15
    > 2: vldmxcsr Md (v1) | WRFSBASE Ry (F3),(11B)
    > 3: vstmxcsr Md (v1) | WRGSBASE Ry (F3),(11B)
    > 4: XSAVE | ptwrite Ey (F3),(11B)
    > -5: XRSTOR | lfence (11B)
    > -6: XSAVEOPT | clwb (66) | mfence (11B)
    > +5: XRSTOR | lfence (11B) | INCSSP Rd (F3),REX.W
    > +6: XSAVEOPT | clwb (66) | mfence (11B) | CLRSSBSY Mq (F3)
    > 7: clflush | clflushopt (66) | sfence (11B)
    > EndTable
    >
    >

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