Modify process handling code to recognise hardware debug registers during copy
and flush operations. Introduce a new TIF_DEBUG task flag to indicate a
process's use of debug register. Load the debug register values into a
new CPU during initialisation.
Signed-off-by: K.Prasad <pra...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/thread_info.h | 2 ++
arch/powerpc/kernel/process.c | 18 ++++++++++++++++++
arch/powerpc/kernel/smp.c | 2 ++
3 files changed, 22 insertions(+)
Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/thread_info.h
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/include/asm/thread_info.h
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/thread_info.h
@@ -114,6 +114,7 @@ static inline struct thread_info *curren
#define TIF_FREEZE 14 /* Freezing for suspend */
#define TIF_RUNLATCH 15 /* Is the runlatch enabled? */
#define TIF_ABI_PENDING 16 /* 32/64 bit switch needed */
+#define TIF_DEBUG 17 /* uses debug registers */
/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
@@ -132,6 +133,7 @@ static inline struct thread_info *curren
#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_RUNLATCH (1<<TIF_RUNLATCH)
#define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING)
+#define _TIF_DEBUG (1<<TIF_DEBUG)
#define _TIF_SYSCALL_T_OR_A
(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
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)))
+ arch_install_thread_hw_breakpoint(new);
+#else
if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
set_dabr(new->thread.dabr);
+#endif /* CONFIG_PPC64 */
#if defined(CONFIG_BOOKE)
/* If new thread DAC (HW breakpoint) is the same then leave it */
@@ -550,6 +558,10 @@ void show_regs(struct pt_regs * regs)
void exit_thread(void)
{
discard_lazy_cpu_state();
+#ifdef CONFIG_PPC64
+ if (unlikely(test_tsk_thread_flag(current, TIF_DEBUG)))
+ flush_thread_hw_breakpoint(current);
+#endif /* CONFIG_PPC64 */
}
void flush_thread(void)
@@ -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);
#else
kregs->nip = (unsigned long)ret_from_fork;
#endif
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/smp.c
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/smp.c
+++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/smp.c
@@ -48,6 +48,7 @@
#include <asm/vdso_datapage.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
+#include <asm/hw_breakpoint.h>
#endif
#ifdef DEBUG
@@ -536,6 +537,7 @@ int __devinit start_secondary(void *unus
local_irq_enable();
+ load_debug_registers();
cpu_idle();
return 0;
}
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