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-rw-r--r--UefiCpuPkg/Library/MpInitLib/MpEqu.inc2
-rw-r--r--UefiCpuPkg/Library/MpInitLib/MpLib.h13
2 files changed, 9 insertions, 6 deletions
diff --git a/UefiCpuPkg/Library/MpInitLib/MpEqu.inc b/UefiCpuPkg/Library/MpInitLib/MpEqu.inc
index 72af196513..317e627b58 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpEqu.inc
+++ b/UefiCpuPkg/Library/MpInitLib/MpEqu.inc
@@ -67,6 +67,8 @@ endstruc
;
; Equivalent NASM structure of MP_CPU_EXCHANGE_INFO
+; Assembly routines should refrain from directly interacting with
+; the internal details of CPU_MP_DATA.
;
struc MP_CPU_EXCHANGE_INFO
.StackStart: CTYPE_UINTN 1
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index af296f6ac0..a96a6389c1 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -203,6 +203,8 @@ typedef struct _CPU_MP_DATA CPU_MP_DATA;
// MP CPU exchange information for AP reset code
// This structure is required to be packed because fixed field offsets
// into this structure are used in assembly code in this module
+// Assembly routines should refrain from directly interacting with
+// the internal details of CPU_MP_DATA.
//
typedef struct {
UINTN StackStart;
@@ -239,17 +241,16 @@ typedef struct {
#pragma pack()
//
-// CPU MP Data save in memory
+// CPU MP Data save in memory, and intended for use in C code.
+// There are some duplicated fields, such as XD status, between
+// CpuMpData and ExchangeInfo. These duplications in CpuMpData
+// are present to avoid to be direct accessed and comprehended
+// in assembly code.
//
struct _CPU_MP_DATA {
UINT64 CpuInfoInHob;
UINT32 CpuCount;
UINT32 BspNumber;
- //
- // The above fields data will be passed from PEI to DXE
- // Please make sure the fields offset same in the different
- // architecture.
- //
SPIN_LOCK MpLock;
UINTN Buffer;
UINTN CpuApStackSize;