UefiCpuPkg/PiSmmCpuDxeSmm: remove unneeded DBs from X64 SmmStartup()

[mirror_edk2.git] / UefiCpuPkg / PiSmmCpuDxeSmm / X64 / SmmInit.nasm

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm
index b147e72180191afae903c082f5a50b59822e41d1..2eaf1433dcd651d72c297213ee2c05fcdcd2f4ba 100644 (file)
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmInit.nasm
@@ -41,26 +41,23 @@ ASM_PFX(gcSmiInitGdtr):
             DQ      0\r
 \r
 global ASM_PFX(SmmStartup)\r
+\r
+BITS 16\r
 ASM_PFX(SmmStartup):\r
-    DB      0x66\r
     mov     eax, 0x80000001             ; read capability\r
     cpuid\r
-    DB      0x66\r
     mov     ebx, edx                    ; rdmsr will change edx. keep it in ebx.\r
     DB      0x66, 0xb8                   ; mov eax, imm32\r
 ASM_PFX(gSmmCr3): DD 0\r
-    mov     cr3, rax\r
-    DB      0x66, 0x2e\r
-    lgdt    [ebp + (ASM_PFX(gcSmiInitGdtr) - ASM_PFX(SmmStartup))]\r
+    mov     cr3, eax\r
+o32 lgdt    [cs:ebp + (ASM_PFX(gcSmiInitGdtr) - ASM_PFX(SmmStartup))]\r
     DB      0x66, 0xb8                   ; mov eax, imm32\r
 ASM_PFX(gSmmCr4): DD 0\r
     or      ah,  2                      ; enable XMM registers access\r
-    mov     cr4, rax\r
-    DB      0x66\r
+    mov     cr4, eax\r
     mov     ecx, 0xc0000080             ; IA32_EFER MSR\r
     rdmsr\r
     or      ah, BIT0                    ; set LME bit\r
-    DB      0x66\r
     test    ebx, BIT20                  ; check NXE capability\r
     jz      .1\r
     or      ah, BIT3                    ; set NXE bit\r
@@ -68,9 +65,11 @@ ASM_PFX(gSmmCr4): DD 0
     wrmsr\r
     DB      0x66, 0xb8                   ; mov eax, imm32\r
 ASM_PFX(gSmmCr0): DD 0\r
-    mov     cr0, rax                    ; enable protected mode & paging\r
+    mov     cr0, eax                    ; enable protected mode & paging\r
     DB      0x66, 0xea                   ; far jmp to long mode\r
 ASM_PFX(gSmmJmpAddr): DQ 0;@LongMode\r
+\r
+BITS 64\r
 @LongMode:                              ; long-mode starts here\r
     DB      0x48, 0xbc                   ; mov rsp, imm64\r
 ASM_PFX(gSmmInitStack): DQ 0\r