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MSR_S_CET EQU 6A2h
MSR_S_CET_SH_STK_EN EQU 1
CR4_CET EQU (1 SHL 23)
N_CR4_CET EQU 23
.code
align 16
AsmDisableCet PROC
mov ecx, MSR_S_CET
rdmsr
test al, MSR_S_CET_SH_STK_EN
jz @F ; if z, shadow stack not enabled
; Pop pushed data for 'call'
mov rax, 1
incsspq rax
@@:
mov rax, cr4
btr eax, N_CR4_CET ; clear CR4_CET
mov cr4, rax
ret
AsmDisableCet ENDP
align 16
AsmEnableCet PROC
mov rax, cr4
bts eax, N_CR4_CET ; set CR4_CET
mov cr4, rax
; Use jmp to skip check for 'ret'
pop rax
jmp rax
AsmEnableCet ENDP
end
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