RFC ARM: add support for hw-breakpoints [v3]

This is version 3 of the RFC patches originally posted at:

v1.) http://lists.infradead.org/pipermail/linux-arm-kernel/2010-February/009084.html
v2.) http://lists.infradead.org/pipermail/linux-arm-kernel/2010-March/011170.html

Changes from v2 include:
- Based on 2.6.35-rc2
- Updated to use new hw-breakpoint API features
- Addressed some comments from Frederic on LKML
- Complete redesign of the ptrace interface so that it follows the ARM ARM (v7) register structure more closely.

Unfortunately, I've only managed to compile-test this and check that the resulting image boots. The main reasons for posting are (a) to support current GDB development and (b) to attract comments on the code.

All comments welcome.

Will Deacon (4):
ARM: hw-breakpoint: add mechanism for hooking into prefetch aborts
ARM: hw-breakpoint: add ARM backend for the hw-breakpoint framework
ARM: hw-breakpoint: add new ptrace requests for hw-breakpoint
interaction
ARM: hw-breakpoint: add HAVE_HW_BREAKPOINT to Kconfig

 arch/arm/Kconfig                     |    1 +
 arch/arm/include/asm/hw_breakpoint.h |  117 ++++++
 arch/arm/include/asm/processor.h     |    4 +
 arch/arm/include/asm/ptrace.h        |    2 +
 arch/arm/include/asm/system.h        |    3 +
 arch/arm/kernel/Makefile             |    1 +
 arch/arm/kernel/hw_breakpoint.c      |  734 ++++++++++++++++++++++++++++++++++
 arch/arm/kernel/ptrace.c             |  196 +++++++++
 arch/arm/mm/fault.c                  |   11 +
 9 files changed, 1069 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/hw_breakpoint.h
 create mode 100644 arch/arm/kernel/hw_breakpoint.c