[RFC PATCH v2 00/10] Machine check handling in linux host.

[Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>]

Hi,

Please find the patch set that performs the machine check handling inside linux
host. The design is to be able to handle re-entrancy so that we do not clobber
the machine check information during nested machine check interrupt.

The patch 2 introduces separate emergency stack in paca structure exclusively
for machine check exception handling.  Patch 3 implements the logic to save the
raw MCE info onto the emergency stack and prepares to take another exception.
Patch 4 and 5 adds CPU-side hooks for early machine check handler and TLB
flush.  The patch 6 and 7 is responsible to detect SLB/TLB errors and flush
them off in the real mode. The patch 9 implements the logic to decode and save
high level MCE information to per cpu buffer without clobbering. The patch 10
adds the basic error handling to the high level C code with MMU on.

I have tested SLB multihit scenario on powernv.

Please review and let me know your comments.

Changes in v2:
- Moved early machine check handling code under CPU_FTR_HVMODE section.
  This makes sure that the early machine check handler will get executed
  only in hypervisor kernel.
- Add dedicated emergency stack for machine check so that we don't end up
  disturbing others who use same emergency stack.
- Fixed the machine check early handle where it used to assume that r1 always
  contains the valid stack pointer.
- Fixed an issue where per-cpu mce_nest_count variable underflows when kvm
  fails to handle MC error and exit the guest.
- Fixed the code to restore r13 before exiting early handler.

Thanks,
-Mahesh.
---

Mahesh Salgaonkar (10):
      powerpc/book3s: Split the common exception prolog logic into two section.
      powerpc/book3s: Introduce exclusive emergency stack for machine check exception.
      powerpc/book3s: handle machine check in Linux host.
      powerpc/book3s: Introduce a early machine check hook in cpu_spec.
      powerpc/book3s: Add flush_tlb operation in cpu_spec.
      powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power7.
      powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power8.
      powerpc/book3s: Decode and save machine check event.
      powerpc/powernv: Remove machine check handling in OPAL.
      powerpc/powernv: Machine check exception handling.


 arch/powerpc/include/asm/bitops.h        |    5 +
 arch/powerpc/include/asm/cputable.h      |   12 +
 arch/powerpc/include/asm/exception-64s.h |   67 ++++---
 arch/powerpc/include/asm/mce.h           |  195 ++++++++++++++++++++
 arch/powerpc/include/asm/paca.h          |    9 +
 arch/powerpc/kernel/Makefile             |    1 
 arch/powerpc/kernel/asm-offsets.c        |    4 
 arch/powerpc/kernel/cpu_setup_power.S    |   38 +++-
 arch/powerpc/kernel/cputable.c           |   16 ++
 arch/powerpc/kernel/exceptions-64s.S     |  108 +++++++++++
 arch/powerpc/kernel/mce.c                |  191 ++++++++++++++++++++
 arch/powerpc/kernel/mce_power.c          |  287 ++++++++++++++++++++++++++++++
 arch/powerpc/kernel/setup_64.c           |    8 +
 arch/powerpc/kernel/traps.c              |   15 ++
 arch/powerpc/kvm/book3s_hv_ras.c         |   50 +++--
 arch/powerpc/platforms/powernv/opal.c    |   84 ++++++---
 arch/powerpc/xmon/xmon.c                 |    2 
 17 files changed, 998 insertions(+), 94 deletions(-)
 create mode 100644 arch/powerpc/include/asm/mce.h
 create mode 100644 arch/powerpc/kernel/mce.c
 create mode 100644 arch/powerpc/kernel/mce_power.c

-- 
-Mahesh