tree d151e2c29e78248cee620cf5094a15316abd17d2
parent f7136c5150c29846d7a1d09109449d96b2f63445
author K.Prasad <prasad@linux.vnet.ibm.com> 1276581919 +0530
committer Paul Mackerras <paulus@samba.org> 1277199650 +1000

powerpc, hw_breakpoints: Implement hw_breakpoints for 64-bit server processors

Implement perf-events based hw-breakpoint interfaces for PowerPC
64-bit server (Book III S) processors.  This allows access to a
given location to be used as an event that can be counted or
profiled by the perf_events subsystem.

This is done using the DABR (data breakpoint register), which can
also be used for process debugging via ptrace.  When perf_event
hw_breakpoint support is configured in, the perf_event subsystem
manages the DABR and arbitrates access to it, and ptrace then
creates a perf_event when it is requested to set a data breakpoint.

[Adopted suggestions from Paul Mackerras <paulus@samba.org> to
- emulate_step() all system-wide breakpoints and single-step only the
  per-task breakpoints
- perform arch-specific cleanup before unregistration through
  arch_unregister_hw_breakpoint()
]

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>