diff options
Diffstat (limited to 'UefiCpuPkg')
| -rw-r--r-- | UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm index 9231aa5b3d..d64fcd48d0 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm @@ -47,6 +47,8 @@ ASM_PFX(SmmStartup): mov eax, 0x80000001 ; read capability
cpuid
mov ebx, edx ; rdmsr will change edx. keep it in ebx.
+ and ebx, BIT20 ; extract NX capability bit
+ shr ebx, 9 ; shift bit to IA32_EFER.NXE[BIT11] position
DB 0x66, 0xb8 ; mov eax, imm32
ASM_PFX(gSmmCr3): DD 0
mov cr3, eax
@@ -56,11 +58,8 @@ ASM_PFX(gSmmCr4): DD 0 mov cr4, eax
mov ecx, 0xc0000080 ; IA32_EFER MSR
rdmsr
- test ebx, BIT20 ; check NXE capability
- jz .1
- or ah, BIT3 ; set NXE bit
+ or eax, ebx ; set NXE bit if NX is available
wrmsr
-.1:
DB 0x66, 0xb8 ; mov eax, imm32
ASM_PFX(gSmmCr0): DD 0
mov di, PROTECT_MODE_DS
|