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UefiCpuPkg: Use Top of each AP's stack to save CpuMpData

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To remove the dependency of CPU register, 4/8 byte at the top of the
stack is occupied for CpuMpData. BIST information is also taken care
here. This modification is only for PEI phase, since in DXE phase
CpuMpData is accessed via global variable.

Signed-off-by: Yuanhao Xie <yuanhao.xie@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
This commit is contained in:
Yuanhao Xie
2022-08-19 14:17:28 +08:00
committed by mergify[bot]
parent 76cf3d35e6
commit 9ab2b34dd4
5 changed files with 59 additions and 13 deletions
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10
UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
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@@ -89,7 +89,7 @@ EnableDebugAgent (
/**
Get pointer to CPU MP Data structure.
For BSP, the pointer is retrieved from HOB.
For AP, the structure is just after IDT.
For AP, the structure is stored in the top of each AP's stack.
@return The pointer to CPU MP Data structure.
**/
@@ -100,15 +100,17 @@ GetCpuMpData (
{
CPU_MP_DATA *CpuMpData;
MSR_IA32_APIC_BASE_REGISTER ApicBaseMsr;
IA32_DESCRIPTOR Idtr;
UINTN ApTopOfStack;
AP_STACK_DATA *ApStackData;
ApicBaseMsr.Uint64 = AsmReadMsr64 (MSR_IA32_APIC_BASE);
if (ApicBaseMsr.Bits.BSP == 1) {
CpuMpData = GetCpuMpDataFromGuidedHob ();
ASSERT (CpuMpData != NULL);
} else {
AsmReadIdtr (&Idtr);
CpuMpData = (CPU_MP_DATA *)(Idtr.Base + Idtr.Limit + 1);
ApTopOfStack = ALIGN_VALUE ((UINTN)&ApTopOfStack, (UINTN)PcdGet32 (PcdCpuApStackSize));
ApStackData = (AP_STACK_DATA *)((UINTN)ApTopOfStack- sizeof (AP_STACK_DATA));
CpuMpData = (CPU_MP_DATA *)ApStackData->MpData;
}
return CpuMpData;