From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH v8 27/27] x86/cet/shstk: Add Shadow Stack instructions to opcode map Date: Fri, 8 Nov 2019 15:27:29 +0200 Message-ID: <15568c48-b950-484d-d176-0f0e38a94bf7@intel.com> References: <20190813205225.12032-1-yu-cheng.yu@intel.com> <20190813205225.12032-28-yu-cheng.yu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190813205225.12032-28-yu-cheng.yu@intel.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Yu-cheng Yu , x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz List-Id: linux-api@vger.kernel.org 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 > --- > 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 > >