powerpc: Hardware breakpoints rewrite to handle non DABR breakpoint registers

This is a rewrite so that we don't assume we are using the DABR throughout the
code.  We now use the arch_hw_breakpoint to store the breakpoint in a generic
manner in the thread_struct, rather than storing the raw DABR value.

The ptrace GET/SET_DEBUGREG interface currently passes the raw DABR in from
userspace.  We keep this functionality, so that future changes (like the POWER8
DAWR), will still fake the DABR to userspace.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 114ea24..a008cf5 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -66,7 +66,7 @@
 int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
 int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
 int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
-int (*__debugger_dabr_match)(struct pt_regs *regs) __read_mostly;
+int (*__debugger_break_match)(struct pt_regs *regs) __read_mostly;
 int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;
 
 EXPORT_SYMBOL(__debugger);
@@ -74,7 +74,7 @@
 EXPORT_SYMBOL(__debugger_bpt);
 EXPORT_SYMBOL(__debugger_sstep);
 EXPORT_SYMBOL(__debugger_iabr_match);
-EXPORT_SYMBOL(__debugger_dabr_match);
+EXPORT_SYMBOL(__debugger_break_match);
 EXPORT_SYMBOL(__debugger_fault_handler);
 #endif