#include "CpuDxe.h"
#include "CpuMp.h"

Functions
EFI_STATUS EFIAPI	GetNumberOfProcessors (IN EFI_MP_SERVICES_PROTOCOL This, OUT UINTN NumberOfProcessors, OUT UINTN *NumberOfEnabledProcessors)

EFI_STATUS EFIAPI	GetProcessorInfo (IN EFI_MP_SERVICES_PROTOCOL This, IN UINTN ProcessorNumber, OUT EFI_PROCESSOR_INFORMATION ProcessorInfoBuffer)

EFI_STATUS EFIAPI	StartupAllAPs (IN EFI_MP_SERVICES_PROTOCOL This, IN EFI_AP_PROCEDURE Procedure, IN BOOLEAN SingleThread, IN EFI_EVENT WaitEvent OPTIONAL, IN UINTN TimeoutInMicroseconds, IN VOID ProcedureArgument OPTIONAL, OUT UINTN **FailedCpuList OPTIONAL)

EFI_STATUS EFIAPI	StartupThisAP (IN EFI_MP_SERVICES_PROTOCOL This, IN EFI_AP_PROCEDURE Procedure, IN UINTN ProcessorNumber, IN EFI_EVENT WaitEvent OPTIONAL, IN UINTN TimeoutInMicroseconds, IN VOID ProcedureArgument OPTIONAL, OUT BOOLEAN *Finished OPTIONAL)

EFI_STATUS EFIAPI	SwitchBSP (IN EFI_MP_SERVICES_PROTOCOL *This, IN UINTN ProcessorNumber, IN BOOLEAN EnableOldBSP)

EFI_STATUS EFIAPI	EnableDisableAP (IN EFI_MP_SERVICES_PROTOCOL This, IN UINTN ProcessorNumber, IN BOOLEAN EnableAP, IN UINT32 HealthFlag OPTIONAL)

EFI_STATUS EFIAPI	WhoAmI (IN EFI_MP_SERVICES_PROTOCOL This, OUT UINTN ProcessorNumber)

VOID	InitializeMpSupport (VOID)

Variables
EFI_HANDLE	mMpServiceHandle = NULL

UINTN	mNumberOfProcessors = 1

EFI_MP_SERVICES_PROTOCOL	mMpServicesTemplate

Detailed Description

CPU DXE Module to produce CPU MP Protocol.

SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file CpuMp.c.

Function Documentation

◆ EnableDisableAP()

EFI_STATUS EFIAPI EnableDisableAP	(	IN EFI_MP_SERVICES_PROTOCOL *	This,
		IN UINTN	ProcessorNumber,
		IN BOOLEAN	EnableAP,
		IN UINT32 *HealthFlag	OPTIONAL
	)

This service lets the caller enable or disable an AP from this point onward. This service may only be called from the BSP.

This service allows the caller enable or disable an AP from this point onward. The caller can optionally specify the health status of the AP by Health. If an AP is being disabled, then the state of the disabled AP is implementation dependent. If an AP is enabled, then the implementation must guarantee that a complete initialization sequence is performed on the AP, so the AP is in a state that is compatible with an MP operating system. This service may not be supported after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled.

If the enable or disable AP operation cannot be completed prior to the return from this service, then EFI_UNSUPPORTED must be returned.

Parameters

[in]	This	A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
[in]	ProcessorNumber	The handle number of AP. 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_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
[in]	EnableAP	Specifies the new state for the processor for enabled, FALSE for disabled.
[in]	HealthFlag	If not NULL, a pointer to a value that specifies the new health status of the AP. This flag corresponds to StatusFlag defined in EFI_MP_SERVICES_PROTOCOL.GetProcessorInfo(). Only the PROCESSOR_HEALTH_STATUS_BIT is used. All other bits are ignored. If it is NULL, this parameter is ignored.

Return values

EFI_SUCCESS	The specified AP was enabled or disabled successfully.
EFI_UNSUPPORTED	Enabling or disabling an AP cannot be completed prior to this service returning.
EFI_UNSUPPORTED	Enabling or disabling an AP is not supported.
EFI_DEVICE_ERROR	The calling processor is an AP.
EFI_NOT_FOUND	Processor with the handle specified by ProcessorNumber does not exist.
EFI_INVALID_PARAMETER	ProcessorNumber specifies the BSP.

Definition at line 471 of file CpuMp.c.

◆ GetNumberOfProcessors()

EFI_STATUS EFIAPI GetNumberOfProcessors	(	IN EFI_MP_SERVICES_PROTOCOL *	This,
		OUT UINTN *	NumberOfProcessors,
		OUT UINTN *	NumberOfEnabledProcessors
	)

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.

This function is used to retrieve the following information:

The number of logical processors that are present in the system.
The number of enabled logical processors in the system at the instant this call is made.

Because MP Service Protocol provides services to enable and disable processors dynamically, the number of enabled logical processors may vary during the course of a boot session.

If this service is called from an AP, then EFI_DEVICE_ERROR is returned. If NumberOfProcessors or NumberOfEnabledProcessors is NULL, then EFI_INVALID_PARAMETER is returned. Otherwise, the total number of processors is returned in NumberOfProcessors, the number of currently enabled processor is returned in NumberOfEnabledProcessors, and EFI_SUCCESS is returned.

Parameters

[in]	This	A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
[out]	NumberOfProcessors	Pointer to the total number of logical processors in the system, including the BSP and disabled APs.
[out]	NumberOfEnabledProcessors	Pointer to the number of enabled logical processors that exist in system, including the BSP.

Return values

EFI_SUCCESS	The number of logical processors and enabled logical processors was retrieved.
EFI_DEVICE_ERROR	The calling processor is an AP.
EFI_INVALID_PARAMETER	NumberOfProcessors is NULL.
EFI_INVALID_PARAMETER	NumberOfEnabledProcessors is NULL.

Definition at line 63 of file CpuMp.c.

◆ GetProcessorInfo()

EFI_STATUS EFIAPI GetProcessorInfo	(	IN EFI_MP_SERVICES_PROTOCOL *	This,
		IN UINTN	ProcessorNumber,
		OUT EFI_PROCESSOR_INFORMATION *	ProcessorInfoBuffer
	)

Gets detailed MP-related information on the requested processor at the instant this call is made. This service may only be called from the BSP.

This service retrieves detailed MP-related information about any processor on the platform. Note the following:

The processor information may change during the course of a boot session.
The information presented here is entirely MP related.

Information regarding the number of caches and their sizes, frequency of operation, slot numbers is all considered platform-related information and is not provided by this service.

Parameters

[in]	This	A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
[in]	ProcessorNumber	The handle number of processor.
[out]	ProcessorInfoBuffer	A pointer to the buffer where information for the requested processor is deposited.

Return values

EFI_SUCCESS	Processor information was returned.
EFI_DEVICE_ERROR	The calling processor is an AP.
EFI_INVALID_PARAMETER	ProcessorInfoBuffer is NULL.
EFI_NOT_FOUND	The processor with the handle specified by ProcessorNumber does not exist in the platform.

Definition at line 107 of file CpuMp.c.

◆ InitializeMpSupport()

VOID InitializeMpSupport ( VOID )

Initialize Multi-processor support.

Definition at line 519 of file CpuMp.c.

◆ StartupAllAPs()

EFI_STATUS EFIAPI StartupAllAPs	(	IN EFI_MP_SERVICES_PROTOCOL *	This,
		IN EFI_AP_PROCEDURE	Procedure,
		IN BOOLEAN	SingleThread,
		IN EFI_EVENT WaitEvent	OPTIONAL,
		IN UINTN	TimeoutInMicroseconds,
		IN VOID *ProcedureArgument	OPTIONAL,
		OUT UINTN **FailedCpuList	OPTIONAL
	)

This service executes a caller provided function on all enabled APs. APs can run either simultaneously or one at a time in sequence. This service supports both blocking and non-blocking requests. The non-blocking requests use EFI events so the BSP can detect when the APs have finished. This service may only be called from the BSP.

This function is used to dispatch all the enabled APs to the function specified by Procedure. If any enabled AP is busy, then EFI_NOT_READY is returned immediately and Procedure is not started on any AP.

If SingleThread is TRUE, all the enabled APs execute the function specified by Procedure one by one, in ascending order of processor handle number. Otherwise, all the enabled APs execute the function specified by Procedure simultaneously.

If WaitEvent is NULL, execution is in blocking mode. The BSP waits until all APs finish or TimeoutInMicroseconds expires. Otherwise, execution is in non-blocking mode, and the BSP returns from this service without waiting for APs. If a non-blocking mode is requested after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled, then EFI_UNSUPPORTED must be returned.

If the timeout specified by TimeoutInMicroseconds expires before all APs return from Procedure, then Procedure on the failed APs is terminated. All enabled APs are always available for further calls to EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and EFI_MP_SERVICES_PROTOCOL.StartupThisAP(). If FailedCpuList is not NULL, its content points to the list of processor handle numbers in which Procedure was terminated.

Note: It is the responsibility of the consumer of the EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() to make sure that the nature of the code that is executed on the BSP and the dispatched APs is well controlled. The MP Services Protocol does not guarantee that the Procedure function is MP-safe. Hence, the tasks that can be run in parallel are limited to certain independent tasks and well-controlled exclusive code. EFI services and protocols may not be called by APs unless otherwise specified.

In blocking execution mode, BSP waits until all APs finish or TimeoutInMicroseconds expires.

In non-blocking execution mode, BSP is freed to return to the caller and then proceed to the next task without having to wait for APs. The following sequence needs to occur in a non-blocking execution mode:

The caller that intends to use this MP Services Protocol in non-blocking mode creates WaitEvent by calling the EFI CreateEvent() service. The caller invokes EFI_MP_SERVICES_PROTOCOL.StartupAllAPs(). If the parameter WaitEvent is not NULL, then StartupAllAPs() executes in non-blocking mode. It requests the function specified by Procedure to be started on all the enabled APs, and releases the BSP to continue with other tasks.
The caller can use the CheckEvent() and WaitForEvent() services to check the state of the WaitEvent created in step 1.
When the APs complete their task or TimeoutInMicroSecondss expires, the MP Service signals WaitEvent by calling the EFI SignalEvent() function. If FailedCpuList is not NULL, its content is available when WaitEvent is signaled. If all APs returned from Procedure prior to the timeout, then FailedCpuList is set to NULL. If not all APs return from Procedure before the timeout, then FailedCpuList is filled in with the list of the failed APs. The buffer is allocated by MP Service Protocol using AllocatePool(). It is the caller's responsibility to free the buffer with FreePool() service.
This invocation of SignalEvent() function informs the caller that invoked EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() that either all the APs completed the specified task or a timeout occurred. The contents of FailedCpuList can be examined to determine which APs did not complete the specified task prior to the timeout.

Parameters

[in]	This	A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
[in]	Procedure	A pointer to the function to be run on enabled APs of the system. See type EFI_AP_PROCEDURE.
[in]	SingleThread	If TRUE, then all the enabled APs execute the function specified by Procedure one by one, in ascending order of processor handle number. If FALSE, then all the enabled APs execute the function specified by Procedure simultaneously.
[in]	WaitEvent	The event created by the caller with CreateEvent() service. If it is NULL, then execute in blocking mode. BSP waits until all APs finish or TimeoutInMicroseconds expires. If it's not NULL, then execute in non-blocking mode. BSP requests the function specified by Procedure to be started on all the enabled APs, and go on executing immediately. If all return from Procedure, or TimeoutInMicroseconds expires, this event is signaled. The BSP can use the CheckEvent() or WaitForEvent() services to check the state of event. Type EFI_EVENT is defined in CreateEvent() in the Unified Extensible Firmware Interface Specification.
[in]	TimeoutInMicroseconds	Indicates the time limit in microseconds for APs to return from Procedure, either for blocking or non-blocking mode. Zero means infinity. If the timeout expires before all APs return from Procedure, then Procedure on the failed APs is terminated. All enabled APs are available for next function assigned by EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() or EFI_MP_SERVICES_PROTOCOL.StartupThisAP(). If the timeout expires in blocking mode, BSP returns EFI_TIMEOUT. If the timeout expires in non-blocking mode, WaitEvent is signaled with SignalEvent().
[in]	ProcedureArgument	The parameter passed into Procedure for all APs.
[out]	FailedCpuList	If NULL, this parameter is ignored. Otherwise, if all APs finish successfully, then its content is set to NULL. If not all APs finish before timeout expires, then its content is set to address of the buffer holding handle numbers of the failed APs. The buffer is allocated by MP Service Protocol, and it's the caller's responsibility to free the buffer with FreePool() service. In blocking mode, it is ready for consumption when the call returns. In non-blocking mode, it is ready when WaitEvent is signaled. The list of failed CPU is terminated by END_OF_CPU_LIST.

Return values

EFI_SUCCESS	In blocking mode, all APs have finished before the timeout expired.
EFI_SUCCESS	In non-blocking mode, function has been dispatched to all enabled APs.
EFI_UNSUPPORTED	A non-blocking mode request was made after the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was signaled.
EFI_DEVICE_ERROR	Caller processor is AP.
EFI_NOT_STARTED	No enabled APs exist in the system.
EFI_NOT_READY	Any enabled APs are busy.
EFI_TIMEOUT	In blocking mode, the timeout expired before all enabled APs have finished.
EFI_INVALID_PARAMETER	Procedure is NULL.

Definition at line 254 of file CpuMp.c.

◆ StartupThisAP()

EFI_STATUS EFIAPI StartupThisAP	(	IN EFI_MP_SERVICES_PROTOCOL *	This,
		IN EFI_AP_PROCEDURE	Procedure,
		IN UINTN	ProcessorNumber,
		IN EFI_EVENT WaitEvent	OPTIONAL,
		IN UINTN	TimeoutInMicroseconds,
		IN VOID *ProcedureArgument	OPTIONAL,
		OUT BOOLEAN *Finished	OPTIONAL
	)

This service lets the caller get one enabled AP to execute a caller-provided function. The caller can request the BSP to either wait for the completion of the AP or just proceed with the next task by using the EFI event mechanism. See EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() for more details on non-blocking execution support. This service may only be called from the BSP.

This function is used to dispatch one enabled AP to the function specified by Procedure passing in the argument specified by ProcedureArgument. If WaitEvent is NULL, execution is in blocking mode. The BSP waits until the AP finishes or TimeoutInMicroSecondss expires. Otherwise, execution is in non-blocking mode. BSP proceeds to the next task without waiting for the AP. If a non-blocking mode is requested after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled, then EFI_UNSUPPORTED must be returned.

If the timeout specified by TimeoutInMicroseconds expires before the AP returns from Procedure, then execution of Procedure by the AP is terminated. The AP is available for subsequent calls to EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() and EFI_MP_SERVICES_PROTOCOL.StartupThisAP().

Parameters

[in]	This	A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
[in]	Procedure	A pointer to the function to be run on the designated AP of the system. See type EFI_AP_PROCEDURE.
[in]	ProcessorNumber	The handle number of the AP. 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_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
[in]	WaitEvent	The event created by the caller with CreateEvent() service. If it is NULL, then execute in blocking mode. BSP waits until this AP finish or TimeoutInMicroSeconds expires. If it's not NULL, then execute in non-blocking mode. BSP requests the function specified by Procedure to be started on this AP, and go on executing immediately. If this AP return from Procedure or TimeoutInMicroSeconds expires, this event is signaled. The BSP can use the CheckEvent() or WaitForEvent() services to check the state of event. Type EFI_EVENT is defined in CreateEvent() in the Unified Extensible Firmware Interface Specification.
[in]	TimeoutInMicroseconds	Indicates the time limit in microseconds for this AP to finish this Procedure, either for blocking or non-blocking mode. Zero means infinity. If the timeout expires before this AP returns from Procedure, then Procedure on the AP is terminated. The AP is available for next function assigned by EFI_MP_SERVICES_PROTOCOL.StartupAllAPs() or EFI_MP_SERVICES_PROTOCOL.StartupThisAP(). If the timeout expires in blocking mode, BSP returns EFI_TIMEOUT. If the timeout expires in non-blocking mode, WaitEvent is signaled with SignalEvent().
[in]	ProcedureArgument	The parameter passed into Procedure on the specified AP.
[out]	Finished	If NULL, this parameter is ignored. In blocking mode, this parameter is ignored. In non-blocking mode, if AP returns from Procedure before the timeout expires, its content is set to TRUE. Otherwise, the value is set to FALSE. The caller can determine if the AP returned from Procedure by evaluating this value.

Return values

EFI_SUCCESS	In blocking mode, specified AP finished before the timeout expires.
EFI_SUCCESS	In non-blocking mode, the function has been dispatched to specified AP.
EFI_UNSUPPORTED	A non-blocking mode request was made after the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was signaled.
EFI_DEVICE_ERROR	The calling processor is an AP.
EFI_TIMEOUT	In blocking mode, the timeout expired before the specified AP has finished.
EFI_NOT_READY	The specified AP is busy.
EFI_NOT_FOUND	The processor with the handle specified by ProcessorNumber does not exist.
EFI_INVALID_PARAMETER	ProcessorNumber specifies the BSP or disabled AP.
EFI_INVALID_PARAMETER	Procedure is NULL.

Definition at line 362 of file CpuMp.c.

◆ SwitchBSP()

EFI_STATUS EFIAPI SwitchBSP	(	IN EFI_MP_SERVICES_PROTOCOL *	This,
		IN UINTN	ProcessorNumber,
		IN BOOLEAN	EnableOldBSP
	)

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. This service may not be supported after the UEFI Event EFI_EVENT_GROUP_READY_TO_BOOT is signaled.

If the BSP cannot be switched prior to the return from this service, then EFI_UNSUPPORTED must be returned.

Parameters

[in]	This	A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
[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_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().
[in]	EnableOldBSP	If TRUE, then the old BSP will be listed as an enabled AP. Otherwise, it will be disabled.

Return values

EFI_SUCCESS	BSP successfully switched.
EFI_UNSUPPORTED	Switching the BSP cannot be completed prior to this service returning.
EFI_UNSUPPORTED	Switching the BSP is not supported.
EFI_DEVICE_ERROR	The calling processor is an AP.
EFI_NOT_FOUND	The processor with the handle specified by ProcessorNumber does not exist.
EFI_INVALID_PARAMETER	ProcessorNumber specifies the current BSP or a disabled AP.
EFI_NOT_READY	The specified AP is busy.

Definition at line 419 of file CpuMp.c.

◆ WhoAmI()

EFI_STATUS EFIAPI WhoAmI	(	IN EFI_MP_SERVICES_PROTOCOL *	This,
		OUT UINTN *	ProcessorNumber
	)

This return the handle number for the calling processor. This service may be called from the BSP and APs.

This service returns the processor handle number for the calling processor. The returned value is in the range from 0 to the total number of logical processors minus 1. The total number of logical processors can be retrieved with EFI_MP_SERVICES_PROTOCOL.GetNumberOfProcessors(). This service may be called from the BSP and APs. If ProcessorNumber is NULL, then EFI_INVALID_PARAMETER is returned. Otherwise, the current processors handle number is returned in ProcessorNumber, and EFI_SUCCESS is returned.

Parameters

[in]	This	A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
[out]	ProcessorNumber	Pointer to the handle number of AP. 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_MP_SERVICES_PROTOCOL.GetNumberOfProcessors().

Return values

EFI_SUCCESS	The current processor handle number was returned in ProcessorNumber.
EFI_INVALID_PARAMETER	ProcessorNumber is NULL.

Definition at line 507 of file CpuMp.c.

Variable Documentation

◆ mMpServiceHandle

EFI_HANDLE mMpServiceHandle = NULL

Definition at line 12 of file CpuMp.c.

◆ mMpServicesTemplate

EFI_MP_SERVICES_PROTOCOL mMpServicesTemplate

Initial value:

= {
  GetNumberOfProcessors,
  GetProcessorInfo,
  StartupAllAPs,
  StartupThisAP,
  SwitchBSP,
  EnableDisableAP,
  WhoAmI
}

Definition at line 15 of file CpuMp.c.

◆ mNumberOfProcessors

UINTN mNumberOfProcessors = 1

Definition at line 13 of file CpuMp.c.

Functions

Variables

Detailed Description

Function Documentation

◆ EnableDisableAP()

◆ GetNumberOfProcessors()

◆ GetProcessorInfo()

◆ InitializeMpSupport()

◆ StartupAllAPs()

◆ StartupThisAP()

◆ SwitchBSP()

◆ WhoAmI()

Variable Documentation

◆ mMpServiceHandle

◆ mMpServicesTemplate

◆ mNumberOfProcessors