Hello,

This is version 2 of the patchset originally posted here:

http://lists.infradead.org/pipermail/linux-arm-kernel/2010-November/032717.html

There are a substantial number of changes:

* Support for CONFIG_PREEMPT kernels.

* Hugely improved watchpoint single-step capabilities without violating
  RCU requirements.

* sparse no longer generates warnings for hw_breakpoint.c.

* We no longer advertise reserved breakpoints to GDB.

All feedback welcome. I would especially value feedback on patch [4/8]
(`disable preemption during debug exception handling') to know if there's
a better solution.


Will Deacon (8):
  ARM: hw_breakpoint: ensure OS lock is clear before writing to debug
    registers
  ARM: hw_breakpoint: reset control registers in hotplug path
  ARM: hw_breakpoint: correct and simplify alignment fixup code
  ARM: hw_breakpoint: disable preemption during debug exception
    handling
  ARM: hw_breakpoint: don't advertise reserved breakpoints
  ARM: hw_breakpoint: do not allocate new breakpoints with
    rcu_read_lock held
  ARM: ptrace: fix style issue with hw_breakpoint interface
  ARM: hw_breakpoint: fix warnings generated by sparse

 arch/arm/include/asm/hw_breakpoint.h |    2 +-
 arch/arm/kernel/entry-armv.S         |    4 +
 arch/arm/kernel/entry-header.S       |   19 ++
 arch/arm/kernel/hw_breakpoint.c      |  464 ++++++++++++++++++++--------------
 arch/arm/kernel/ptrace.c             |    4 +-
 5 files changed, 305 insertions(+), 188 deletions(-)