[PATCH v2 0/3] arm64/ras: support sea error recovery

[Xie XiuQi]

With ARM v8.2 RAS Extension, SEA are usually triggered when memory errors
are consumed. In some cases, if the error address is in a clean page or a
read-only page, there is a chance to recover. Such as error occurs in a
instruction page, we can reread this page from disk instead of killing process.

Because memory_failure() may sleep, we can not call it directly in SEA exception
context. So we saved faulting physical address associated with a process in the
ghes handler and set __TIF_SEA_NOTIFY. When we return from SEA exception context
and get into do_notify_resume() before the process running, we could check it
and call memory_failure() to do recovery. It's safe, because we are in process
context.

In some platform, when SEA triggerred, physical address could be
reported by memory section or by processor section, so we save 
address at this two place.

This patchset is only for internal review, and it's only compiled OK,
not yet tested now.

---
v2 - v1:
  - wrap arm_proc_error_check and log_arm_hw_error in a single arm_process_error()
  - fix sea_save_info return value issue
  - fix link error if this CONFIG_ARM64_ERR_RECOV is not selected
  - use a notify chain instead of call arch_apei_report_mem_error directly

  https://lkml.org/lkml/2017/9/1/189

Xie XiuQi (3):
  arm64/ras: support sea error recovery
  GHES: add a notify chain for process memory section
  arm64/ras: save error address from memory section for recovery

 arch/arm64/Kconfig                   |  11 +++
 arch/arm64/include/asm/ras.h         |  36 ++++++++
 arch/arm64/include/asm/thread_info.h |   4 +-
 arch/arm64/kernel/Makefile           |   1 +
 arch/arm64/kernel/ras.c              | 174 +++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/signal.c           |   8 ++
 arch/arm64/mm/fault.c                |  27 ++++--
 drivers/acpi/apei/ghes.c             |  14 ++-
 include/acpi/ghes.h                  |   8 ++
 9 files changed, 272 insertions(+), 11 deletions(-)
 create mode 100644 arch/arm64/include/asm/ras.h
 create mode 100644 arch/arm64/kernel/ras.c

-- 
1.8.3.1