hw-breakpoint interfaces for BookE - ver II

Hi All,
Please find a new version of the patch that implements generic
hw-breakpoint interfaces for PowerPC BookIII E.

While there are several improvements over the previous version in terms of code placement, support for ptrace and fixes for incorrect issues, the patch remains compile-tested (only)(against 44x/iss476-smp_defconfig config) and is yet to be tested on hardware (for functionality).

Changelog Version II
(Version I:linuxppc-dev message-id: [email protected])
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- ptrace requests (through PTRACE_SET_DEBUGREG and PTRACE_GET_DEBUGREG) are now supported.
- Changes in original arch/powerpc/kernel/hw_breakpoint.c have been percolated down to hw_breakpoint_booke.c (such as introduction of thread_change_pc(), arch_unregister_hw_breakpoint() and changes to hw_breakpoint_handler()) along with some code re-arrangement (for brevity/clarity).

The usage of CONFIG (in this patch) option doesn't largely represent a form that it would turn into after enabling the use of DVCs, DACs by non-ptrace breakpoint requests. They should turn correct as versions of this patch progress.

Kindly let me know your comments.

Thanks,
K.Prasad