[PATCH 0/3] hw_breakpoint: Fix and simplify local address updates for wprobe

[Jinchao Wang]

Hi Masami,

While reviewing wprobe v10, I prepared three patches to fix and simplify
the HWBP support required by wprobe.

This series is based on linux-trace/probes/for-next, the same base used by
wprobe v10. It is intended to replace patches 5-7 in v10, so it should not
be applied on top of topic/wprobe-v2.

Patch 1 fixes the x86 HWBP slot and DR7 races when an operation is
interrupted by an NMI.

Patch 2 adds arch_modify_local_hw_breakpoint_addr(), which updates only
the watched address of an installed breakpoint on the local CPU.

Patch 3 adds the matching generic modify_local_hw_breakpoint_addr() API.
It keeps the original patch structure and Masami's authorship, while
removing attribute parsing, type/length updates and rollback.

With the address-only interface, the install/uninstall refactoring in the
old patch 5 is no longer needed.

I can take care of follow-up maintenance related to fast local HWBP
watched-address updates.

The patches passed checkpatch and the relevant x86_32 and x86_64 object
builds.

Jinchao Wang (2):
  x86/hw_breakpoints: Make DR7 updates NMI safe
  x86/hw_breakpoints: Add arch_modify_local_hw_breakpoint_addr() API

Masami Hiramatsu (Google) (1):
  HWBP: Add modify_local_hw_breakpoint_addr() API

 arch/Kconfig                         |   8 ++
 arch/x86/Kconfig                     |   1 +
 arch/x86/include/asm/debugreg.h      |  36 ++++++---
 arch/x86/include/asm/hw_breakpoint.h |   2 +
 arch/x86/kernel/cpu/mce/core.c       |  20 +++--
 arch/x86/kernel/hw_breakpoint.c      | 114 ++++++++++++++++-----------
 arch/x86/kernel/nmi.c                |  10 ++-
 arch/x86/kernel/traps.c              |  10 ++-
 include/linux/hw_breakpoint.h        |   6 ++
 kernel/events/hw_breakpoint.c        |  30 +++++++
 10 files changed, 166 insertions(+), 71 deletions(-)


base-commit: 1a416ae446afa42d2d8500ce25bd61c564508721
-- 
2.53.0