diff options
Diffstat (limited to 'UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm')
| -rw-r--r-- | UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm index 1d67f510e9..bfcdbd31c1 100644 --- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm +++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm @@ -179,6 +179,14 @@ ProgramStack: mov esp, dword [edi + CPU_INFO_IN_HOB.ApTopOfStack]
CProcedureInvoke:
+ ;
+ ; Reserve 4 bytes for CpuMpData.
+ ; When the AP wakes up again via INIT-SIPI-SIPI, push 0 will cause the existing CpuMpData to be overwritten with 0.
+ ; CpuMpData is filled in via InitializeApData() during the first time INIT-SIPI-SIPI,
+ ; while overwirrten may occurs when under ApInHltLoop but InitFlag is not set to ApInitConfig.
+ ; Therefore reservation is implemented by sub esp instead of push 0.
+ ;
+ sub esp, 4
push ebp ; push BIST data at top of AP stack
xor ebp, ebp ; clear ebp for call stack trace
push ebp
|