Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff....@intel.com>
CC: Feng Tian <feng.t...@intel.com>
CC: Jiewen Yao <jiewen....@intel.com>
CC: Michael Kinney <michael.d.kin...@intel.com>
---
UefiCpuPkg/CpuMpPei/CpuMpPei.h | 12 ++++
UefiCpuPkg/CpuMpPei/Ia32/MpEqu.inc | 4 ++
UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.asm | 79 ++++++++++++++++++++
UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.nasm | 74 +++++++++++++++++++
UefiCpuPkg/CpuMpPei/PeiMpServices.c | 132 ++++++++++++++++++++++++++++++++++
UefiCpuPkg/CpuMpPei/PeiMpServices.h | 65 +++++++++++++++++
UefiCpuPkg/CpuMpPei/X64/MpEqu.inc | 3 +
UefiCpuPkg/CpuMpPei/X64/MpFuncs.asm | 106 +++++++++++++++++++++++++++
UefiCpuPkg/CpuMpPei/X64/MpFuncs.nasm | 106 +++++++++++++++++++++++++++
9 files changed, 581 insertions(+)
diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.h b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
index ed6cf05..d8ee2ee 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.h
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
@@ -58,6 +58,16 @@ typedef struct {
UINTN RendezvousFunnelSize;
} MP_ASSEMBLY_ADDRESS_MAP;
+//
+// CPU exchange information for switch BSP
+//
+typedef struct {
+ UINT8 State; // offset 0
+ UINTN StackPointer; // offset 4 / 8
+ IA32_DESCRIPTOR Gdtr; // offset 8 / 16
+ IA32_DESCRIPTOR Idtr; // offset 14 / 26
+} CPU_EXCHANGE_ROLE_INFO;
+
typedef struct _PEI_CPU_MP_DATA PEI_CPU_MP_DATA;
#pragma pack()
@@ -124,6 +134,8 @@ struct _PEI_CPU_MP_DATA {
UINTN ApFunctionArgument;
volatile UINT32 FinishedCount;
BOOLEAN InitFlag;
+ CPU_EXCHANGE_ROLE_INFO BSPInfo;
+ CPU_EXCHANGE_ROLE_INFO APInfo;
MTRR_SETTINGS MtrrTable;
PEI_CPU_DATA *CpuData;
volatile MP_CPU_EXCHANGE_INFO *MpCpuExchangeInfo;
diff --git a/UefiCpuPkg/CpuMpPei/Ia32/MpEqu.inc
b/UefiCpuPkg/CpuMpPei/Ia32/MpEqu.inc
index 1f02dad..50ec8c9 100644
--- a/UefiCpuPkg/CpuMpPei/Ia32/MpEqu.inc
+++ b/UefiCpuPkg/CpuMpPei/Ia32/MpEqu.inc
@@ -24,6 +24,10 @@ PROTECT_MODE_DS equ 18h
VacantFlag equ 00h
NotVacantFlag equ 0ffh
+CPU_SWITCH_STATE_IDLE equ 0
+CPU_SWITCH_STATE_STORED equ 1
+CPU_SWITCH_STATE_LOADED equ 2
+
LockLocation equ (RendezvousFunnelProcEnd -
RendezvousFunnelProcStart)
StackStartAddressLocation equ LockLocation + 04h
StackSizeLocation equ LockLocation + 08h
diff --git a/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.asm
b/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.asm
index 9861472..63c8048 100644
--- a/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.asm
+++ b/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.asm
@@ -161,6 +161,85 @@ AsmGetAddressMap PROC near C PUBLIC
ret
AsmGetAddressMap ENDP
+PAUSE32 MACRO
+ DB 0F3h
+ DB 090h
+ ENDM
+
+;-------------------------------------------------------------------------------------
+;AsmExchangeRole procedure follows. This procedure executed by current BSP,
that is
+;about to become an AP. It switches it'stack with the current AP.
+;AsmExchangeRole (IN CPU_EXCHANGE_INFO *MyInfo, IN CPU_EXCHANGE_INFO
*OthersInfo);
+;-------------------------------------------------------------------------------------
+AsmExchangeRole PROC near C PUBLIC
+ ; DO NOT call other functions in this function, since 2 CPU may use 1 stack
+ ; at the same time. If 1 CPU try to call a function, stack will be
corrupted.
+ pushad
+ mov ebp,esp
+
+ ; esi contains MyInfo pointer
+ mov esi, dword ptr [ebp+24h]
+
+ ; edi contains OthersInfo pointer
+ mov edi, dword ptr [ebp+28h]
+
+ ;Store EFLAGS, GDTR and IDTR register to stack
+ pushfd
+ mov eax, cr4
+ push eax ; push cr4 firstly
+ mov eax, cr0
+ push eax
+
+ sgdt fword ptr [esi+8]
+ sidt fword ptr [esi+14]
+
+ ; Store the its StackPointer
+ mov dword ptr [esi+4],esp
+
+ ; update its switch state to STORED
+ mov byte ptr [esi], CPU_SWITCH_STATE_STORED
+
+WaitForOtherStored:
+ ; wait until the other CPU finish storing its state
+ cmp byte ptr [edi], CPU_SWITCH_STATE_STORED
+ jz OtherStored
+ PAUSE32
+ jmp WaitForOtherStored
+
+OtherStored:
+ ; Since another CPU already stored its state, load them
+ ; load GDTR value
+ lgdt fword ptr [edi+8]
+
+ ; load IDTR value
+ lidt fword ptr [edi+14]
+
+ ; load its future StackPointer
+ mov esp, dword ptr [edi+4]
+
+ ; update the other CPU's switch state to LOADED
+ mov byte ptr [edi], CPU_SWITCH_STATE_LOADED
+
+WaitForOtherLoaded:
+ ; wait until the other CPU finish loading new state,
+ ; otherwise the data in stack may corrupt
+ cmp byte ptr [esi], CPU_SWITCH_STATE_LOADED
+ jz OtherLoaded
+ PAUSE32
+ jmp WaitForOtherLoaded
+
+OtherLoaded:
+ ; since the other CPU already get the data it want, leave this procedure
+ pop eax
+ mov cr0, eax
+ pop eax
+ mov cr4, eax
+ popfd
+
+ popad
+ ret
+AsmExchangeRole ENDP
+
AsmInitializeGdt PROC near C PUBLIC
push ebp
mov ebp, esp
diff --git a/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.nasm
b/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.nasm
index a3c4ae9..fe45cf1 100644
--- a/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.nasm
+++ b/UefiCpuPkg/CpuMpPei/Ia32/MpFuncs.nasm
@@ -149,6 +149,80 @@ ASM_PFX(AsmGetAddressMap):
popad
ret
+;-------------------------------------------------------------------------------------
+;AsmExchangeRole procedure follows. This procedure executed by current BSP,
that is
+;about to become an AP. It switches it'stack with the current AP.
+;AsmExchangeRole (IN CPU_EXCHANGE_INFO *MyInfo, IN CPU_EXCHANGE_INFO
*OthersInfo);
+;-------------------------------------------------------------------------------------
+global ASM_PFX(AsmExchangeRole)
+ASM_PFX(AsmExchangeRole):
+ ; DO NOT call other functions in this function, since 2 CPU may use 1 stack
+ ; at the same time. If 1 CPU try to call a function, stack will be
corrupted.
+ pushad
+ mov ebp,esp
+
+ ; esi contains MyInfo pointer
+ mov esi, [ebp + 24h]
+
+ ; edi contains OthersInfo pointer
+ mov edi, [ebp + 28h]
+
+ ;Store EFLAGS, GDTR and IDTR register to stack
+ pushfd
+ mov eax, cr4
+ push eax ; push cr4 firstly
+ mov eax, cr0
+ push eax
+
+ sgdt [esi + 8]
+ sidt [esi + 14]
+
+ ; Store the its StackPointer
+ mov [esi + 4],esp
+
+ ; update its switch state to STORED
+ mov byte [esi], CPU_SWITCH_STATE_STORED
+
+WaitForOtherStored:
+ ; wait until the other CPU finish storing its state
+ cmp byte [edi], CPU_SWITCH_STATE_STORED
+ jz OtherStored
+ pause
+ jmp WaitForOtherStored
+
+OtherStored:
+ ; Since another CPU already stored its state, load them
+ ; load GDTR value
+ lgdt [edi + 8]
+
+ ; load IDTR value
+ lidt [edi + 14]
+
+ ; load its future StackPointer
+ mov esp, [edi + 4]
+
+ ; update the other CPU's switch state to LOADED
+ mov byte [edi], CPU_SWITCH_STATE_LOADED
+
+WaitForOtherLoaded:
+ ; wait until the other CPU finish loading new state,
+ ; otherwise the data in stack may corrupt
+ cmp byte [esi], CPU_SWITCH_STATE_LOADED
+ jz OtherLoaded
+ pause
+ jmp WaitForOtherLoaded
+
+OtherLoaded:
+ ; since the other CPU already get the data it want, leave this procedure
+ pop eax
+ mov cr0, eax
+ pop eax
+ mov cr4, eax
+ popfd
+
+ popad
+ ret
+
global ASM_PFX(AsmInitializeGdt)
ASM_PFX(AsmInitializeGdt):
push ebp
diff --git a/UefiCpuPkg/CpuMpPei/PeiMpServices.c
b/UefiCpuPkg/CpuMpPei/PeiMpServices.c
index bf10a48..9a89045 100644
--- a/UefiCpuPkg/CpuMpPei/PeiMpServices.c
+++ b/UefiCpuPkg/CpuMpPei/PeiMpServices.c
@@ -154,6 +154,25 @@ GetProcessorNumber (
}
/**
+ Worker function for SwitchBSP().
+
+ Worker function for SwitchBSP(), assigned to the AP which is intended to
become BSP.
+
+ @param Buffer Pointer to CPU MP Data
+**/
+VOID
+EFIAPI
+FutureBSPProc (
+ IN VOID *Buffer
+ )
+{
+ PEI_CPU_MP_DATA *DataInHob;
+
+ DataInHob = (PEI_CPU_MP_DATA *) Buffer;
+ AsmExchangeRole (&DataInHob->APInfo, &DataInHob->BSPInfo);
+}
+
+/**
This service retrieves the number of logical processor in the platform
and the number of those logical processors that are enabled on this boot.
This service may only be called from the BSP.
@@ -631,6 +650,119 @@ PeiStartupThisAP (
return Status;
}
+/**
+ This service switches the requested AP to be the BSP from that point onward.
+ This service changes the BSP for all purposes. This call can only be
performed
+ by the current BSP.
+
+ This service switches the requested AP to be the BSP from that point onward.
+ This service changes the BSP for all purposes. The new BSP can take over the
+ execution of the old BSP and continue seamlessly from where the old one left
+ off.
+
+ If the BSP cannot be switched prior to the return from this service, then
+ EFI_UNSUPPORTED must be returned.
+
+ @param[in] PeiServices General purpose services available to every
PEIM.
+ @param[in] This A pointer to the EFI_PEI_MP_SERVICES_PPI
instance.
+ @param[in] ProcessorNumber The handle number of AP that is to become the
new
+ BSP. The range is from 0 to the total number of
+ logical processors minus 1. The total number of
+ logical processors can be retrieved by
+ EFI_PEI_MP_SERVICES_PPI.GetNumberOfProcessors().
+ @param[in] EnableOldBSP If TRUE, then the old BSP will be listed as an
+ enabled AP. Otherwise, it will be disabled.
+
+ @retval EFI_SUCCESS BSP successfully switched.
+ @retval EFI_UNSUPPORTED Switching the BSP cannot be completed prior
to
+ this service returning.
+ @retval EFI_UNSUPPORTED Switching the BSP is not supported.
+ @retval EFI_SUCCESS The calling processor is an AP.
+ @retval EFI_NOT_FOUND The processor with the handle specified by
+ ProcessorNumber does not exist.
+ @retval EFI_INVALID_PARAMETER ProcessorNumber specifies the current BSP or
+ a disabled AP.
+ @retval EFI_NOT_READY The specified AP is busy.
+
+**/
+EFI_STATUS
+EFIAPI
+PeiSwitchBSP (
+ IN CONST EFI_PEI_SERVICES **PeiServices,
+ IN EFI_PEI_MP_SERVICES_PPI *This,
+ IN UINTN ProcessorNumber,
+ IN BOOLEAN EnableOldBSP
+ )
+{
+ PEI_CPU_MP_DATA *PeiCpuMpData;
+ UINTN CallerNumber;
+ MSR_IA32_APIC_BASE ApicBaseMsr;
+
+ PeiCpuMpData = GetMpHobData ();
+ if (PeiCpuMpData == NULL) {
+ return EFI_NOT_FOUND;
+ }
+
+ //
+ // Check whether caller processor is BSP
+ //
+ PeiWhoAmI (PeiServices, This, &CallerNumber);
+ if (CallerNumber != PeiCpuMpData->BspNumber) {
+ return EFI_SUCCESS;
+ }
+
+ if (ProcessorNumber >= PeiCpuMpData->CpuCount) {
+ return EFI_NOT_FOUND;
+ }
+
+ //
+ // Check whether specified AP is disabled
+ //
+ if (PeiCpuMpData->CpuData[ProcessorNumber].State == CpuStateDisabled) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // Check whether ProcessorNumber specifies the current BSP
+ //
+ if (ProcessorNumber == PeiCpuMpData->BspNumber) {
+ return EFI_INVALID_PARAMETER;
+ }
+
+ //
+ // Check whether specified AP is busy
+ //
+ if (PeiCpuMpData->CpuData[ProcessorNumber].State == CpuStateBusy) {
+ return EFI_NOT_READY;
+ }
+
+ //
+ // Clear the BSP bit of MSR_IA32_APIC_BASE
+ //
+ ApicBaseMsr.Uint64 = AsmReadMsr64 (MSR_IA32_APIC_BASE_ADDRESS);
+ ApicBaseMsr.Bits.Bsp = 0;
+ AsmWriteMsr64 (MSR_IA32_APIC_BASE_ADDRESS, ApicBaseMsr.Uint64);
+
+ PeiCpuMpData->BSPInfo.State = CPU_SWITCH_STATE_IDLE;
+ PeiCpuMpData->APInfo.State = CPU_SWITCH_STATE_IDLE;
+
+ //
+ // Need to wakeUp AP (future BSP).
+ //
+ WakeUpAP (PeiCpuMpData, FALSE,
PeiCpuMpData->CpuData[ProcessorNumber].ApicId, FutureBSPProc, PeiCpuMpData);
+
+ AsmExchangeRole (&PeiCpuMpData->BSPInfo, &PeiCpuMpData->APInfo);
+
+ //
+ // Set the BSP bit of MSR_IA32_APIC_BASE on new BSP
+ //
+ ApicBaseMsr.Uint64 = AsmReadMsr64 (MSR_IA32_APIC_BASE_ADDRESS);
+ ApicBaseMsr.Bits.Bsp = 1;
+ AsmWriteMsr64 (MSR_IA32_APIC_BASE_ADDRESS, ApicBaseMsr.Uint64);
+
+ return EFI_SUCCESS;
+}
+
/**
This return the handle number for the calling processor. This service may be
diff --git a/UefiCpuPkg/CpuMpPei/PeiMpServices.h
b/UefiCpuPkg/CpuMpPei/PeiMpServices.h
index cafa783..fe8b459 100644
--- a/UefiCpuPkg/CpuMpPei/PeiMpServices.h
+++ b/UefiCpuPkg/CpuMpPei/PeiMpServices.h
@@ -17,10 +17,31 @@
#include "CpuMpPei.h"
+//
+// The MP data for switch BSP
+//
+#define CPU_SWITCH_STATE_IDLE 0
+#define CPU_SWITCH_STATE_STORED 1
+#define CPU_SWITCH_STATE_LOADED 2
#define CPU_CHECK_AP_INTERVAL 0x100 // 100 microseconds
/**
+ This function is called by both the BSP and the AP which is to become the
BSP to
+ Exchange execution context including stack between them. After return from
this
+ function, the BSP becomes AP and the AP becomes the BSP.
+
+ @param MyInfo Pointer to buffer holding the exchanging information for
the executing processor.
+ @param OthersInfo Pointer to buffer holding the exchanging information for
the peer.
+**/
+VOID
+EFIAPI
+AsmExchangeRole (
+ IN CPU_EXCHANGE_ROLE_INFO *MyInfo,
+ IN CPU_EXCHANGE_ROLE_INFO *OthersInfo
+ );
+
+/**
This service retrieves the number of logical processor in the platform
and the number of those logical processors that are enabled on this boot.
This service may only be called from the BSP.
@@ -243,6 +264,50 @@ PeiStartupThisAP (
IN VOID *ProcedureArgument OPTIONAL
);
+/**
+ This service switches the requested AP to be the BSP from that point onward.
+ This service changes the BSP for all purposes. This call can only be
performed
+ by the current BSP.
+
+ This service switches the requested AP to be the BSP from that point onward.
+ This service changes the BSP for all purposes. The new BSP can take over the
+ execution of the old BSP and continue seamlessly from where the old one left
+ off.
+
+ If the BSP cannot be switched prior to the return from this service, then
+ EFI_UNSUPPORTED must be returned.
+
+ @param[in] PeiServices General purpose services available to every
PEIM.
+ @param[in] This A pointer to the EFI_PEI_MP_SERVICES_PPI
instance.
+ @param[in] ProcessorNumber The handle number of AP that is to become the
new
+ BSP. The range is from 0 to the total number of
+ logical processors minus 1. The total number of
+ logical processors can be retrieved by
+ EFI_PEI_MP_SERVICES_PPI.GetNumberOfProcessors().
+ @param[in] EnableOldBSP If TRUE, then the old BSP will be listed as an
+ enabled AP. Otherwise, it will be disabled.
+
+ @retval EFI_SUCCESS BSP successfully switched.
+ @retval EFI_UNSUPPORTED Switching the BSP cannot be completed prior
to
+ this service returning.
+ @retval EFI_UNSUPPORTED Switching the BSP is not supported.
+ @retval EFI_SUCCESS The calling processor is an AP.
+ @retval EFI_NOT_FOUND The processor with the handle specified by
+ ProcessorNumber does not exist.
+ @retval EFI_INVALID_PARAMETER ProcessorNumber specifies the current BSP or
+ a disabled AP.
+ @retval EFI_NOT_READY The specified AP is busy.
+
+**/
+EFI_STATUS
+EFIAPI
+PeiSwitchBSP (
+ IN CONST EFI_PEI_SERVICES **PeiServices,
+ IN EFI_PEI_MP_SERVICES_PPI *This,
+ IN UINTN ProcessorNumber,
+ IN BOOLEAN EnableOldBSP
+ );
+
/**
This return the handle number for the calling processor. This service may be
diff --git a/UefiCpuPkg/CpuMpPei/X64/MpEqu.inc
b/UefiCpuPkg/CpuMpPei/X64/MpEqu.inc
index 28a826c..946fe50 100644
--- a/UefiCpuPkg/CpuMpPei/X64/MpEqu.inc
+++ b/UefiCpuPkg/CpuMpPei/X64/MpEqu.inc
@@ -26,6 +26,9 @@ LONG_MODE_DS equ 30h
VacantFlag equ 00h
NotVacantFlag equ 0ffh
+CPU_SWITCH_STATE_IDLE equ 0
+CPU_SWITCH_STATE_STORED equ 1
+CPU_SWITCH_STATE_LOADED equ 2
LockLocation equ (RendezvousFunnelProcEnd -
RendezvousFunnelProcStart)
StackStartAddressLocation equ LockLocation + 08h
diff --git a/UefiCpuPkg/CpuMpPei/X64/MpFuncs.asm
b/UefiCpuPkg/CpuMpPei/X64/MpFuncs.asm
index 9e85fac..6622c43 100644
--- a/UefiCpuPkg/CpuMpPei/X64/MpFuncs.asm
+++ b/UefiCpuPkg/CpuMpPei/X64/MpFuncs.asm
@@ -193,6 +193,112 @@ AsmGetAddressMap PROC
ret
AsmGetAddressMap ENDP
+;-------------------------------------------------------------------------------------
+;AsmExchangeRole procedure follows. This procedure executed by current BSP,
that is
+;about to become an AP. It switches it'stack with the current AP.
+;AsmExchangeRole (IN CPU_EXCHANGE_INFO *MyInfo, IN CPU_EXCHANGE_INFO
*OthersInfo);
+;-------------------------------------------------------------------------------------
+AsmExchangeRole PROC
+ ; DO NOT call other functions in this function, since 2 CPU may use 1 stack
+ ; at the same time. If 1 CPU try to call a function, stack will be
corrupted.
+
+ push rax
+ push rbx
+ push rcx
+ push rdx
+ push rsi
+ push rdi
+ push rbp
+ push r8
+ push r9
+ push r10
+ push r11
+ push r12
+ push r13
+ push r14
+ push r15
+
+ mov rax, cr0
+ push rax
+
+ mov rax, cr4
+ push rax
+
+ ; rsi contains MyInfo pointer
+ mov rsi, rcx
+
+ ; rdi contains OthersInfo pointer
+ mov rdi, rdx
+
+ ;Store EFLAGS, GDTR and IDTR regiter to stack
+ pushfq
+ sgdt fword ptr [rsi + 16]
+ sidt fword ptr [rsi + 26]
+
+ ; Store the its StackPointer
+ mov qword ptr [rsi + 8], rsp
+
+ ; update its switch state to STORED
+ mov byte ptr [rsi], CPU_SWITCH_STATE_STORED
+
+WaitForOtherStored:
+ ; wait until the other CPU finish storing its state
+ cmp byte ptr [rdi], CPU_SWITCH_STATE_STORED
+ jz OtherStored
+ pause
+ jmp WaitForOtherStored
+
+OtherStored:
+ ; Since another CPU already stored its state, load them
+ ; load GDTR value
+ lgdt fword ptr [rdi + 16]
+
+ ; load IDTR value
+ lidt fword ptr [rdi + 26]
+
+ ; load its future StackPointer
+ mov rsp, qword ptr [rdi + 8]
+
+ ; update the other CPU's switch state to LOADED
+ mov byte ptr [rdi], CPU_SWITCH_STATE_LOADED
+
+WaitForOtherLoaded:
+ ; wait until the other CPU finish loading new state,
+ ; otherwise the data in stack may corrupt
+ cmp byte ptr [rsi], CPU_SWITCH_STATE_LOADED
+ jz OtherLoaded
+ pause
+ jmp WaitForOtherLoaded
+
+OtherLoaded:
+ ; since the other CPU already get the data it want, leave this procedure
+ popfq
+
+ pop rax
+ mov cr4, rax
+
+ pop rax
+ mov cr0, rax
+
+ pop r15
+ pop r14
+ pop r13
+ pop r12
+ pop r11
+ pop r10
+ pop r9
+ pop r8
+ pop rbp
+ pop rdi
+ pop rsi
+ pop rdx
+ pop rcx
+ pop rbx
+ pop rax
+
+ ret
+AsmExchangeRole ENDP
+
AsmInitializeGdt PROC
push rbp
mov rbp, rsp
diff --git a/UefiCpuPkg/CpuMpPei/X64/MpFuncs.nasm
b/UefiCpuPkg/CpuMpPei/X64/MpFuncs.nasm
index 09c2fbc..8b93c0d 100644
--- a/UefiCpuPkg/CpuMpPei/X64/MpFuncs.nasm
+++ b/UefiCpuPkg/CpuMpPei/X64/MpFuncs.nasm
@@ -187,6 +187,112 @@ ASM_PFX(AsmGetAddressMap):
mov qword [rcx + 18h], RendezvousFunnelProcEnd -
RendezvousFunnelProcStart
ret
+;-------------------------------------------------------------------------------------
+;AsmExchangeRole procedure follows. This procedure executed by current BSP,
that is
+;about to become an AP. It switches it'stack with the current AP.
+;AsmExchangeRole (IN CPU_EXCHANGE_INFO *MyInfo, IN CPU_EXCHANGE_INFO
*OthersInfo);
+;-------------------------------------------------------------------------------------
+global ASM_PFX(AsmExchangeRole)
+ASM_PFX(AsmExchangeRole):
+ ; DO NOT call other functions in this function, since 2 CPU may use 1 stack
+ ; at the same time. If 1 CPU try to call a function, stack will be
corrupted.
+
+ push rax
+ push rbx
+ push rcx
+ push rdx
+ push rsi
+ push rdi
+ push rbp
+ push r8
+ push r9
+ push r10
+ push r11
+ push r12
+ push r13
+ push r14
+ push r15
+
+ mov rax, cr0
+ push rax
+
+ mov rax, cr4
+ push rax
+
+ ; rsi contains MyInfo pointer
+ mov rsi, rcx
+
+ ; rdi contains OthersInfo pointer
+ mov rdi, rdx
+
+ ;Store EFLAGS, GDTR and IDTR regiter to stack
+ pushfq
+ sgdt [rsi + 16]
+ sidt [rsi + 26]
+
+ ; Store the its StackPointer
+ mov [rsi + 8], rsp
+
+ ; update its switch state to STORED
+ mov byte [rsi], CPU_SWITCH_STATE_STORED
+
+WaitForOtherStored:
+ ; wait until the other CPU finish storing its state
+ cmp byte [rdi], CPU_SWITCH_STATE_STORED
+ jz OtherStored
+ pause
+ jmp WaitForOtherStored
+
+OtherStored:
+ ; Since another CPU already stored its state, load them
+ ; load GDTR value
+ lgdt [rdi + 16]
+
+ ; load IDTR value
+ lidt [rdi + 26]
+
+ ; load its future StackPointer
+ mov rsp, [rdi + 8]
+
+ ; update the other CPU's switch state to LOADED
+ mov byte [rdi], CPU_SWITCH_STATE_LOADED
+
+WaitForOtherLoaded:
+ ; wait until the other CPU finish loading new state,
+ ; otherwise the data in stack may corrupt
+ cmp byte [rsi], CPU_SWITCH_STATE_LOADED
+ jz OtherLoaded
+ pause
+ jmp WaitForOtherLoaded
+
+OtherLoaded:
+ ; since the other CPU already get the data it want, leave this procedure
+ popfq
+
+ pop rax
+ mov cr4, rax
+
+ pop rax
+ mov cr0, rax
+
+ pop r15
+ pop r14
+ pop r13
+ pop r12
+ pop r11
+ pop r10
+ pop r9
+ pop r8
+ pop rbp
+ pop rdi
+ pop rsi
+ pop rdx
+ pop rcx
+ pop rbx
+ pop rax
+
+ ret
+
global ASM_PFX(AsmInitializeGdt)
ASM_PFX(AsmInitializeGdt):
push rbp
--
1.9.5.msysgit.0
------------------------------------------------------------------------------
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