Juno includes a system-level wakeup timer which is an implementation of the ARM Generic Timer architecture. The CNTCTL frame contains some registers that are accessible using a Non-Secure access. Juno R0 incorrectly limits these accesses to Secure access only. This issue is documented in the Juno Errata 832219: APB port security breaks SBSA compliance https://developer.arm.com/documentation/epm008857/latest
This results in a crash when the OS tries to access these registers. Therefore, disable memory mapped platform timers for Juno R0. Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org> Cc: Thomas Abraham <thomas.abra...@arm.com> Cc: Sudeep Holla <sudeep.ho...@arm.com> Signed-off-by: Sami Mujawar <sami.muja...@arm.com> Reported-by: Sudeep Holla <sudeep.ho...@arm.com> --- The changes can be seen at: https://github.com/samimujawar/edk2-platforms/tree/1496_junor0_disable_memmap_plat_timers_v1 Platform/ARM/JunoPkg/ConfigurationManager/ConfigurationManagerDxe/ConfigurationManager.c | 48 ++++++++++++-------- 1 file changed, 30 insertions(+), 18 deletions(-) diff --git a/Platform/ARM/JunoPkg/ConfigurationManager/ConfigurationManagerDxe/ConfigurationManager.c b/Platform/ARM/JunoPkg/ConfigurationManager/ConfigurationManagerDxe/ConfigurationManager.c index 48f0fd370f073c8fed1a649d8c4ab28b062a8290..91f035480dcfe81e93febfac2ef703d6c77737f1 100644 --- a/Platform/ARM/JunoPkg/ConfigurationManager/ConfigurationManagerDxe/ConfigurationManager.c +++ b/Platform/ARM/JunoPkg/ConfigurationManager/ConfigurationManagerDxe/ConfigurationManager.c @@ -1,7 +1,7 @@ /** @file Configuration Manager Dxe - Copyright (c) 2017 - 2022, Arm Limited. All rights reserved.<BR> + Copyright (c) 2017 - 2023, Arm Limited. All rights reserved.<BR> SPDX-License-Identifier: BSD-2-Clause-Patent @@ -1380,26 +1380,38 @@ GetArmNameSpaceObject ( break; case EArmObjPlatformGTBlockInfo: - Status = HandleCmObject ( - CmObjectId, - PlatformRepo->GTBlockInfo, - sizeof (PlatformRepo->GTBlockInfo), - ARRAY_SIZE (PlatformRepo->GTBlockInfo), - CmObject - ); + if (PlatformRepo->JunoRevision == JUNO_REVISION_R0) { + // Disable Memory Mapped Platform Timers for Juno R0 + // due to Juno Erratum 832219. + Status = EFI_NOT_FOUND; + } else { + Status = HandleCmObject ( + CmObjectId, + PlatformRepo->GTBlockInfo, + sizeof (PlatformRepo->GTBlockInfo), + ARRAY_SIZE (PlatformRepo->GTBlockInfo), + CmObject + ); + } break; case EArmObjGTBlockTimerFrameInfo: - Status = HandleCmObjectRefByToken ( - This, - CmObjectId, - PlatformRepo->GTBlock0TimerInfo, - sizeof (PlatformRepo->GTBlock0TimerInfo), - ARRAY_SIZE (PlatformRepo->GTBlock0TimerInfo), - Token, - GetGTBlockTimerFrameInfo, - CmObject - ); + if (PlatformRepo->JunoRevision == JUNO_REVISION_R0) { + // Disable Memory Mapped Platform Timers for Juno R0 + // due to Juno Erratum 832219. + Status = EFI_NOT_FOUND; + } else { + Status = HandleCmObjectRefByToken ( + This, + CmObjectId, + PlatformRepo->GTBlock0TimerInfo, + sizeof (PlatformRepo->GTBlock0TimerInfo), + ARRAY_SIZE (PlatformRepo->GTBlock0TimerInfo), + Token, + GetGTBlockTimerFrameInfo, + CmObject + ); + } break; case EArmObjGicCInfo: -- 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)' -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#106149): https://edk2.groups.io/g/devel/message/106149 Mute This Topic: https://groups.io/mt/99569509/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
