[RFC PATCH v6 26/26] x86/cet/shstk: Add Shadow Stack instructions to opcode map

From: Yu-cheng Yu
Date: Mon Nov 19 2018 - 16:54:40 EST

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@xxxxxxxxx>
---
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
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

--
2.17.1