/** @file
When installed, the MP Services Protocol produces a collection of services
that are needed for MP management.
The MP Services Protocol provides a generalized way of performing following tasks:
- Retrieving information of multi-processor environment and MP-related status of
specific processors.
- Dispatching user-provided function to APs.
- Maintain MP-related processor status.
The MP Services Protocol must be produced on any system with more than one logical
processor.
The Protocol is available only during boot time.
MP Services Protocol is hardware-independent. Most of the logic of this protocol
is architecturally neutral. It abstracts the multi-processor environment and
status of processors, and provides interfaces to retrieve information, maintain,
and dispatch.
MP Services Protocol may be consumed by ACPI module. The ACPI module may use this
protocol to retrieve data that are needed for an MP platform and report them to OS.
MP Services Protocol may also be used to program and configure processors, such
as MTRR synchronization for memory space attributes setting in DXE Services.
MP Services Protocol may be used by non-CPU DXE drivers to speed up platform boot
by taking advantage of the processing capabilities of the APs, for example, using
APs to help test system memory in parallel with other device initialization.
Diagnostics applications may also use this protocol for multi-processor.
Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.
This program and the accompanying materials are licensed and made available under
the terms and conditions of the BSD License that accompanies this distribution.
The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
@par Revision Reference:
This Protocol is defined in the UEFI Platform Initialization Specification 1.2,
Volume 2:Driver Execution Environment Core Interface.
**/
#ifndef _MP_SERVICE_PROTOCOL_H_
#define _MP_SERVICE_PROTOCOL_H_
///
/// Global ID for the EFI_MP_SERVICES_PROTOCOL.
///
#define EFI_MP_SERVICES_PROTOCOL_GUID \
{ \
0x3fdda605, 0xa76e, 0x4f46, {0xad, 0x29, 0x12, 0xf4, 0x53, 0x1b, 0x3d, 0x08} \
}
///
/// Forward declaration for the EFI_MP_SERVICES_PROTOCOL.
///
typedef struct _EFI_MP_SERVICES_PROTOCOL EFI_MP_SERVICES_PROTOCOL;
///
/// Terminator for a list of failed CPUs returned by StartAllAPs().
///
#define END_OF_CPU_LIST 0xffffffff
///
/// This bit is used in the StatusFlag field of EFI_PROCESSOR_INFORMATION and
/// indicates whether the processor is playing the role of BSP. If the bit is 1,
/// then the processor is BSP. Otherwise, it is AP.
///
#define PROCESSOR_AS_BSP_BIT 0x00000001
///
/// This bit is used in the StatusFlag field of EFI_PROCESSOR_INFORMATION and
/// indicates whether the processor is enabled. If the bit is 1, then the
/// processor is enabled. Otherwise, it is disabled.
///
#define PROCESSOR_ENABLED_BIT 0x00000002
///
/// This bit is used in the StatusFlag field of EFI_PROCESSOR_INFORMATION and
/// indicates whether the processor is healthy. If the bit is 1, then the
/// processor is healthy. Otherwise, some fault has been detected for the processor.
///
#define PROCESSOR_HEALTH_STATUS_BIT 0x00000004
///
/// Structure that describes the pyhiscal location of a logical CPU.
///
typedef struct {
///
/// Zero-based physical package number that identifies the cartridge of the processor.
///
UINT32 Package;
///
/// Zero-based physical core number within package of the processor.
///
UINT32 Core;
///
/// Zero-based logical thread number within core of the processor.
///
UINT32 Thread;
} EFI_CPU_PHYSICAL_LOCATION;
///
/// Structure that describes information about a logical CPU.
///
typedef struct {
///
/// The unique processor ID determined by system hardware. For IA32 and X64,
/// the processor ID is the same as the Local APIC ID. Only the lower 8 bits
/// are used, and higher bits are reserved. For IPF, the lower 16 bits contains
/// id/eid, and higher bits are reserved.
///
UINT64 ProcessorId;
///
/// Flags indicating if the processor is BSP or AP, if the processor is enabled
/// or disabled, and if the processor is healthy. Bits 3..31 are reserved and
/// must be 0.
///
///
/// BSP ENABLED HEALTH Description
/// === ======= ====== ===================================================
/// 0 0 0 Unhealthy Disabled AP.
/// 0 0 1 Healthy Disabled AP.
/// 0 1 0 Unhealthy Enabled AP.
/// 0 1 1 Healthy Enabled AP.
/// 1 0 0 Invalid. The BSP can never be in the disabled state.
/// 1 0 1 Invalid. The BSP can never be in the disabled state.
/// 1 1 0 Unhealthy Enabled BSP.
/// 1 1 1 Healthy Enabled BSP.
///
///
UINT32 StatusFlag;
///
/// The physical location of the processor, including the physical package number
/// that identifies the cartridge, the physical core number within package, and
/// logical thread number within core.
///
EFI_CPU_PHYSICAL_LOCATION Location;
} EFI_PROCESSOR_INFORMATION;
/**
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.
@param[in] This A pointer to the EFI_MP_SERVICES_PROTOCOL
instance.
@param[out] NumberOfProcessors Pointer to the total number of logical
processors in the system, including the BSP
and disabled APs.
@param[out] NumberOfEnabledProcessors Pointer to the number of enabled logical
processors that exist in system, including
the BSP.
@retval EFI_SUCCESS The number of logical processors and enabled
logical processors was retrieved.
@retval EFI_DEVICE_ERROR The calling processor is an AP.
@retval EFI_INVALID_PARAMETER NumberOfProcessors is NULL.
@retval EFI_INVALID_PARAMETER NumberOfEnabledProcessors is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_MP_SERVICES_GET_NUMBER_OF_PROCESSORS)(
IN EFI_MP_SERVICES_PROTOCOL *This,
OUT UINTN *NumberOfProcessors,
OUT UINTN *NumberOfEnabledProcessors
);
/**
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.
@param[in] This A pointer to the EFI_MP_SERVICES_PROTOCOL
instance.
@param[in] ProcessorNumber The handle number of processor.
@param[out] ProcessorInfoBuffer A pointer to the buffer where information for
the requested processor is deposited.
@retval EFI_SUCCESS Processor information was returned.
@retval EFI_DEVICE_ERROR The calling processor is an AP.
@retval EFI_INVALID_PARAMETER ProcessorInfoBuffer is NULL.
@retval EFI_NOT_FOUND The processor with the handle specified by
ProcessorNumber does not exist in the platform.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_MP_SERVICES_GET_PROCESSOR_INFO)(
IN EFI_MP_SERVICES_PROTOCOL *This,
IN UINTN ProcessorNumber,
OUT EFI_PROCESSOR_INFORMATION *ProcessorInfoBuffer
);
/**
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 TimeoutInMicroSecs 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.
@param[in] This A pointer to the EFI_MP_SERVICES_PROTOCOL
instance.
@param[in] Procedure A pointer to the function to be run on
enabled APs of the system. See type
EFI_AP_PROCEDURE.
@param[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.
@param[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.
@param[in] TimeoutInMicrosecsond 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().
@param[in] ProcedureArgument The parameter passed into Procedure for
all APs.
@param[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.
@retval EFI_SUCCESS In blocking mode, all APs have finished before
the timeout expired.
@retval EFI_SUCCESS In non-blocking mode, function has been dispatched
to all enabled APs.
@retval EFI_UNSUPPORTED A non-blocking mode request was made after the
UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
signaled.
@retval EFI_DEVICE_ERROR Caller processor is AP.
@retval EFI_NOT_STARTED No enabled APs exist in the system.
@retval EFI_NOT_READY Any enabled APs are busy.
@retval EFI_TIMEOUT In blocking mode, the timeout expired before
all enabled APs have finished.
@retval EFI_INVALID_PARAMETER Procedure is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_MP_SERVICES_STARTUP_ALL_APS)(
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 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().
@param[in] This A pointer to the EFI_MP_SERVICES_PROTOCOL
instance.
@param[in] Procedure A pointer to the function to be run on the
designated AP of the system. See type
EFI_AP_PROCEDURE.
@param[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().
@param[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.
@param[in] TimeoutInMicrosecsond 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().
@param[in] ProcedureArgument The parameter passed into Procedure on the
specified AP.
@param[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.
@retval EFI_SUCCESS In blocking mode, specified AP finished before
the timeout expires.
@retval EFI_SUCCESS In non-blocking mode, the function has been
dispatched to specified AP.
@retval EFI_UNSUPPORTED A non-blocking mode request was made after the
UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was
signaled.
@retval EFI_DEVICE_ERROR The calling processor is an AP.
@retval EFI_TIMEOUT In blocking mode, the timeout expired before
the specified AP has finished.
@retval EFI_NOT_READY The specified AP is busy.
@retval EFI_NOT_FOUND The processor with the handle specified by
ProcessorNumber does not exist.
@retval EFI_INVALID_PARAMETER ProcessorNumber specifies the BSP or disabled AP.
@retval EFI_INVALID_PARAMETER Procedure is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_MP_SERVICES_STARTUP_THIS_AP)(
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 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.
@param[in] This A pointer to the EFI_MP_SERVICES_PROTOCOL 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_MP_SERVICES_PROTOCOL.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.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_MP_SERVICES_SWITCH_BSP)(
IN EFI_MP_SERVICES_PROTOCOL *This,
IN UINTN ProcessorNumber,
IN BOOLEAN EnableOldBSP
);
/**
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.
@param[in] This A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
@param[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().
@param[in] EnableAP Specifies the new state for the processor for
enabled, FALSE for disabled.
@param[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.
@retval EFI_SUCCESS The specified AP was enabled or disabled successfully.
@retval EFI_UNSUPPORTED Enabling or disabling an AP cannot be completed
prior to this service returning.
@retval EFI_UNSUPPORTED Enabling or disabling an AP is not supported.
@retval EFI_DEVICE_ERROR The calling processor is an AP.
@retval EFI_NOT_FOUND Processor with the handle specified by ProcessorNumber
does not exist.
@retval EFI_INVALID_PARAMETER ProcessorNumber specifies the BSP.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_MP_SERVICES_ENABLEDISABLEAP)(
IN EFI_MP_SERVICES_PROTOCOL *This,
IN UINTN ProcessorNumber,
IN BOOLEAN EnableAP,
IN UINT32 *HealthFlag OPTIONAL
);
/**
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.
@param[in] This A pointer to the EFI_MP_SERVICES_PROTOCOL instance.
@param[in] 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().
@retval EFI_SUCCESS The current processor handle number was returned
in ProcessorNumber.
@retval EFI_INVALID_PARAMETER ProcessorNumber is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_MP_SERVICES_WHOAMI)(
IN EFI_MP_SERVICES_PROTOCOL *This,
OUT UINTN *ProcessorNumber
);
///
/// When installed, the MP Services Protocol produces a collection of services
/// that are needed for MP management.
///
/// Before the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT is signaled, the module
/// that produces this protocol is required to place all APs into an idle state
/// whenever the APs are disabled or the APs are not executing code as requested
/// through the StartupAllAPs() or StartupThisAP() services. The idle state of
/// an AP before the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT is signaled is
/// implementation dependent.
///
/// After the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT is signaled, all the APs
/// must be placed in the OS compatible CPU state as defined by the UEFI
/// Specification. Implementations of this protocol may use the UEFI event
/// EFI_EVENT_GROUP_READY_TO_BOOT to force APs into the OS compatible state as
/// defined by the UEFI Specification. Modules that use this protocol must
/// guarantee that all non-blocking mode requests on all APs have been completed
/// before the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT is signaled. Since the
/// order that event notification functions in the same event group are executed
/// is not deterministic, an event of type EFI_EVENT_GROUP_READY_TO_BOOT cannot
/// be used to guarantee that APs have completed their non-blocking mode requests.
///
/// When the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT is signaled, the StartAllAPs()
/// and StartupThisAp() services must no longer support non-blocking mode requests.
/// The support for SwitchBSP() and EnableDisableAP() may no longer be supported
/// after this event is signaled. Since UEFI Applications and UEFI OS Loaders
/// execute after the UEFI event EFI_EVENT_GROUP_READY_TO_BOOT is signaled, these
/// UEFI images must be aware that the functionality of this protocol may be reduced.
///
struct _EFI_MP_SERVICES_PROTOCOL {
EFI_MP_SERVICES_GET_NUMBER_OF_PROCESSORS GetNumberOfProcessors;
EFI_MP_SERVICES_GET_PROCESSOR_INFO GetProcessorInfo;
EFI_MP_SERVICES_STARTUP_ALL_APS StartupAllAPs;
EFI_MP_SERVICES_STARTUP_THIS_AP StartupThisAP;
EFI_MP_SERVICES_SWITCH_BSP SwitchBSP;
EFI_MP_SERVICES_ENABLEDISABLEAP EnableDisableAP;
EFI_MP_SERVICES_WHOAMI WhoAmI;
};
extern EFI_GUID gEfiMpServiceProtocolGuid;
#endif