Currently, both synchronous and asynchronous error are queued and handled by a dedicated kthread in workqueue. Memory failure for synchronous error is synced by a trick. Although the task could be killed by page fault, the memory failure is handled in a kthread context so that the hwpoison-aware mechanisms, e.g. PF_MCE_EARLY, early kill, does not work as expected. To this end, separate synchronous and asynchronous error handling into different paths like X86 does: - task work for synchronous error. - and workqueue for asynchronous error. This patch set is based on a new UEFI proposal submitted by our colleague Yingwen.[1] > Background: > > In ARM world, two type events (Sync/Async) from hardware IP need OS/VMM take different actions. > Current CPER memory error record is not able to distinguish sync/async type event right now. > Current OS/VMM need to take extra actions beyond CPER which is heavy burden to identify the > two type events > > Sync event (e.g. CPU consume poisoned data) --> Firmware -> CPER error log --> OS/VMM take recovery action. > Async event (e.g. Memory controller detect UE event) --> Firmware --> CPER error log --> OS take page action. > > > Proposal: > > - In section description Flags field(UEFI spec section N.2, add sync flag as below. OS/VMM > could depend on this flag to distinguish sync/async events. > - Bit8 – sync flag; if set this flag indicates that this event record is synchronous(e.g. > cpu core consumes poison data, then cause instruction/data abort); if not set, this event record is asynchronous. > > Best regards, > Yingwen Chen > > [ Shuai Xue: The thread is only opened to the member of UEFI Workgroup. > Paste here for discussion.] [1] https://members.uefi.org/wg/uswg/mail/thread/9453 Shuai Xue (2): ACPI: APEI: set memory failure flags as MF_ACTION_REQUIRED on synchronous events ACPI: APEI: separate synchronous error handling into task work drivers/acpi/apei/ghes.c | 120 ++++++++++++++++++++++----------------- include/linux/cper.h | 22 +++++++ 2 files changed, 89 insertions(+), 53 deletions(-) -- 2.20.1.12.g72788fdb
