From 5aae8a53708025d4e718f0d2e7c2f766779ddc71 Mon Sep 17 00:00:00 2001 From: "K.Prasad" Date: Tue, 15 Jun 2010 11:35:19 +0530 Subject: powerpc, hw_breakpoints: Implement hw_breakpoints for 64-bit server processors Implement perf-events based hw-breakpoint interfaces for PowerPC 64-bit server (Book III S) processors. This allows access to a given location to be used as an event that can be counted or profiled by the perf_events subsystem. This is done using the DABR (data breakpoint register), which can also be used for process debugging via ptrace. When perf_event hw_breakpoint support is configured in, the perf_event subsystem manages the DABR and arbitrates access to it, and ptrace then creates a perf_event when it is requested to set a data breakpoint. [Adopted suggestions from Paul Mackerras to - emulate_step() all system-wide breakpoints and single-step only the per-task breakpoints - perform arch-specific cleanup before unregistration through arch_unregister_hw_breakpoint() ] Signed-off-by: K.Prasad Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/process.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 9d255b4f0a0e..cbf3521d50b6 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include @@ -462,8 +463,14 @@ struct task_struct *__switch_to(struct task_struct *prev, #ifdef CONFIG_PPC_ADV_DEBUG_REGS switch_booke_debug_regs(&new->thread); #else +/* + * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would + * schedule DABR + */ +#ifndef CONFIG_HAVE_HW_BREAKPOINT if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) set_dabr(new->thread.dabr); +#endif /* CONFIG_HAVE_HW_BREAKPOINT */ #endif @@ -642,7 +649,11 @@ void flush_thread(void) { discard_lazy_cpu_state(); +#ifdef CONFIG_HAVE_HW_BREAKPOINTS + flush_ptrace_hw_breakpoint(current); +#else /* CONFIG_HAVE_HW_BREAKPOINTS */ set_debug_reg_defaults(¤t->thread); +#endif /* CONFIG_HAVE_HW_BREAKPOINTS */ } void @@ -660,6 +671,9 @@ void prepare_to_copy(struct task_struct *tsk) flush_altivec_to_thread(current); flush_vsx_to_thread(current); flush_spe_to_thread(current); +#ifdef CONFIG_HAVE_HW_BREAKPOINT + flush_ptrace_hw_breakpoint(tsk); +#endif /* CONFIG_HAVE_HW_BREAKPOINT */ } /* -- cgit v1.2.3