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>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 58d0572de6f9..01006040f59e 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -34,6 +34,7 @@ obj-y				+= vdso32/
 obj-$(CONFIG_PPC64)             += setup_64.o sys_ppc32.o \
                                    signal_64.o ptrace32.o \
                                    paca.o nvram_64.o firmware.o
+obj-$(CONFIG_HAVE_HW_BREAKPOINT)        += hw_breakpoint.o
 obj-$(CONFIG_PPC_BOOK3S_64)     += cpu_setup_ppc970.o cpu_setup_pa6t.o
 obj64-$(CONFIG_RELOCATABLE)     += reloc_64.o
 obj-$(CONFIG_PPC_BOOK3E_64)     += exceptions-64e.o