Re: [PATCH v7 27/27] x86/cet/shstk: Add Shadow Stack instructions to opcode map

Adrian Hunter
2019-11-01T14:05:00Z

On 6/06/19 11:06 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.

Does the notrack prefix also need to be catered for somehow?

>
> 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

AFAICT WRSS does not have 66 prefix

> 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
> 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
>
>