diff --git a/UefiCpuPkg/CpuDxe/CpuMp.c b/UefiCpuPkg/CpuDxe/CpuMp.c index b576d18ca4..878cdf25db 100644 --- a/UefiCpuPkg/CpuDxe/CpuMp.c +++ b/UefiCpuPkg/CpuDxe/CpuMp.c @@ -30,7 +30,7 @@ EFI_MP_SERVICES_PROTOCOL mMpServicesTemplate = { GetProcessorInfo, StartupAllAPs, StartupThisAP, - NULL, // SwitchBSP, + SwitchBSP, EnableDisableAP, WhoAmI }; @@ -891,6 +891,55 @@ StartupThisAP ( return EFI_SUCCESS; } +/** + 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. + +**/ +EFI_STATUS +EFIAPI +SwitchBSP ( + IN EFI_MP_SERVICES_PROTOCOL *This, + IN UINTN ProcessorNumber, + IN BOOLEAN EnableOldBSP + ) +{ + // + // Current always return unsupported. + // + return EFI_UNSUPPORTED; +} + /** This service lets the caller enable or disable an AP from this point onward. This service may only be called from the BSP. diff --git a/UefiCpuPkg/CpuDxe/CpuMp.h b/UefiCpuPkg/CpuDxe/CpuMp.h index 2b3b9b23d4..a53ef52d93 100644 --- a/UefiCpuPkg/CpuDxe/CpuMp.h +++ b/UefiCpuPkg/CpuDxe/CpuMp.h @@ -465,6 +465,49 @@ StartupThisAP ( 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. + +**/ +EFI_STATUS +EFIAPI +SwitchBSP ( + 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.