[AVR32] Enable debugging only when needed

Keep track of processes being debugged (including the kernel itself)
and turn the OCD system on and off as appropriate. Since enabling
debugging turns off some optimizations in the CPU core, this fixes the
issue that enabling KProbes support or simply running a program under
gdbserver will reduce system performance significantly until the next
reboot.

The CPU performance will still be reduced for all processes while a
process is being debugged, but this is a lot better than reducing the
performance forever.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/include/asm-avr32/ptrace.h b/include/asm-avr32/ptrace.h
index 8c5dba5e33df..9e2d44f4e0fe 100644
--- a/include/asm-avr32/ptrace.h
+++ b/include/asm-avr32/ptrace.h
@@ -121,7 +121,15 @@ struct pt_regs {
 };
 
 #ifdef __KERNEL__
-# define user_mode(regs) (((regs)->sr & MODE_MASK) == MODE_USER)
+
+#include <asm/ocd.h>
+
+#define arch_ptrace_attach(child)       ocd_enable(child)
+
+#define user_mode(regs)                 (((regs)->sr & MODE_MASK) == MODE_USER)
+#define instruction_pointer(regs)       ((regs)->pc)
+#define profile_pc(regs)                instruction_pointer(regs)
+
 extern void show_regs (struct pt_regs *);
 
 static __inline__ int valid_user_regs(struct pt_regs *regs)
@@ -141,9 +149,6 @@ static __inline__ int valid_user_regs(struct pt_regs *regs)
         return 0;
 }
 
-#define instruction_pointer(regs) ((regs)->pc)
-
-#define profile_pc(regs) instruction_pointer(regs)
 
 #endif /* __KERNEL__ */