powerpc/booke: Add support for advanced debug registers

powerpc/booke: Add support for advanced debug registers

From: Dave Kleikamp <shaggy@linux.vnet.ibm.com>

Based on patches originally written by Torez Smith.

This patch defines context switch and trap related functionality
for BookE specific Debug Registers. It adds support to ptrace()
for setting and getting BookE related Debug Registers

Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Torez Smith  <lnxtorez@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <dwg@au1.ibm.com>
Cc: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Sergio Durigan Junior <sergiodj@br.ibm.com>
Cc: Thiago Jung Bauermann <bauerman@br.ibm.com>
Cc: linuxppc-dev list <Linuxppc-dev@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index ad7044b5a2c7..a0afb555a7c9 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -140,17 +140,15 @@ static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs)
                 return 0;               /* no signals delivered */
         }
 
+#ifndef CONFIG_PPC_ADV_DEBUG_REGS
         /*
          * Reenable the DABR before delivering the signal to
          * user space. The DABR will have been cleared if it
          * triggered inside the kernel.
          */
-        if (current->thread.dabr) {
+        if (current->thread.dabr)
                 set_dabr(current->thread.dabr);
-#ifdef CONFIG_PPC_ADV_DEBUG_REGS
-                mtspr(SPRN_DBCR0, current->thread.dbcr0);
 #endif
-        }
 
         if (is32) {
                 if (ka.sa.sa_flags & SA_SIGINFO)