Re: [RFC Patch 4/6] Modify process handling code to handle hardware debug registers

Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/process.c
===================================================================

--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/process.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/process.c

@@ -50,6 +50,7 @@
 #include <asm/syscalls.h>
 #ifdef CONFIG_PPC64
 #include <asm/firmware.h>
+#include <asm/hw_breakpoint.h>
 #endif
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>

@@ -254,8 +255,10 @@ void do_dabr(struct pt_regs *regs, unsig
 			11, SIGSEGV) == NOTIFY_STOP)
 		return;
 
+#ifndef CONFIG_PPC64
 	if (debugger_dabr_match(regs))
 		return;
+#endif
 
 	/* Clear the DAC and struct entries.  One shot trigger */
 #if defined(CONFIG_BOOKE)

@@ -372,8 +375,13 @@ struct task_struct *__switch_to(struct t
 
 #endif /* CONFIG_SMP */
 
+#ifdef CONFIG_PPC64
+		if (unlikely(test_tsk_thread_flag(new, TIF_DEBUG)))
+			switch_to_thread_hw_breakpoint(new);
+#else

@@ -605,6 +617,9 @@ int copy_thread(unsigned long clone_flag
 	struct pt_regs *childregs, *kregs;
 	extern void ret_from_fork(void);
 	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+#ifdef CONFIG_PPC64
+	struct task_struct *tsk = current;
+#endif
 
 	CHECK_FULL_REGS(regs);
 	/* Copy registers */

@@ -672,6 +687,9 @@ int copy_thread(unsigned long clone_flag
 	 * function.
  	 */
 	kregs->nip = *((unsigned long *)ret_from_fork);
+
+	if (unlikely(test_tsk_thread_flag(tsk, TIF_DEBUG)))
+		copy_thread_hw_breakpoint(tsk, p, clone_flags);