UefiCpuPkg/PiSmmCpuDxeSmm: update comments in IA32 SmmStartup()

The gSmmCr3, gSmmCr4, gSmmCr0 and gSmmJmpAddr global variables are used
for patching assembly instructions, thus we can't yet remove the DB
encodings for those instructions. At least we should add the intended
meanings in comments.

This patch only changes comments.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
[lersek@redhat.com: adapt commit msg to ongoing PatchAssembly discussion]

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm
index e96dd8d2392aea0d321100d455c829a8c98b182b..08534dba64b71cc11065638f5d3af7bd67b9710f 100644 (file)
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm
@@ -47,12 +47,12 @@ ASM_PFX(SmmStartup):
     cpuid\r
     DB      0x66\r
     mov     ebx, edx                    ; rdmsr will change edx. keep it in ebx.\r
-    DB      0x66, 0xb8\r
+    DB      0x66, 0xb8                  ; mov eax, imm32\r
 ASM_PFX(gSmmCr3): DD 0\r
     mov     cr3, eax\r
     DB      0x67, 0x66\r
     lgdt    [cs:ebp + (ASM_PFX(gcSmiInitGdtr) - ASM_PFX(SmmStartup))]\r
-    DB      0x66, 0xb8\r
+    DB      0x66, 0xb8                  ; mov eax, imm32\r
 ASM_PFX(gSmmCr4): DD 0\r
     mov     cr4, eax\r
     DB      0x66\r
@@ -64,11 +64,11 @@ ASM_PFX(gSmmCr4): DD 0
     or      ah, BIT3                    ; set NXE bit\r
     wrmsr\r
 .1:\r
-    DB      0x66, 0xb8\r
+    DB      0x66, 0xb8                  ; mov eax, imm32\r
 ASM_PFX(gSmmCr0): DD 0\r
     DB      0xbf, PROTECT_MODE_DS, 0    ; mov di, PROTECT_MODE_DS\r
     mov     cr0, eax\r
-    DB      0x66, 0xea                   ; jmp far [ptr48]\r
+    DB      0x66, 0xea                  ; jmp far [ptr48]\r
 ASM_PFX(gSmmJmpAddr):\r
     DD      @32bit\r
     DW      PROTECT_MODE_CS\r