UefiCpuPkg/MpInitLib: Enhance waiting for AP initialization logic.

[mirror_edk2.git] / UefiCpuPkg / Library / MpInitLib / Ia32 / MpFuncs.nasm

diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
index 1b9c6a62f8fe9320b545b826af94f0eef45cf0b0..2b6c27d4ec675f6389436ce3862b01b22284a5b1 100644 (file)
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
@@ -86,6 +86,12 @@ Flat32Start:                                   ; protected mode entry point
 \r
     mov        esi, ebx\r
 \r
+    ; Increment the number of APs executing here as early as possible\r
+    ; This is decremented in C code when AP is finished executing\r
+    mov        edi, esi\r
+    add        edi, NumApsExecutingLocation\r
+    lock inc   dword [edi]\r
+\r
     mov         edi, esi\r
     add         edi, EnableExecuteDisableLocation\r
     cmp         byte [edi], 0\r