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| author | K.Prasad <prasad@linux.vnet.ibm.com> | 2010-06-15 11:35:19 +0530 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2010-06-22 19:40:50 +1000 |
| commit | 5aae8a53708025d4e718f0d2e7c2f766779ddc71 (patch) | |
| tree | d151e2c29e78248cee620cf5094a15316abd17d2 /arch/powerpc/kernel/process.c | |
| parent | f7136c5150c29846d7a1d09109449d96b2f63445 (diff) | |
| download | kernel_samsung_smdk4412-5aae8a53708025d4e718f0d2e7c2f766779ddc71.zip kernel_samsung_smdk4412-5aae8a53708025d4e718f0d2e7c2f766779ddc71.tar.gz kernel_samsung_smdk4412-5aae8a53708025d4e718f0d2e7c2f766779ddc71.tar.bz2 | |
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 <paulus@samba.org> 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 <prasad@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/process.c')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 9d255b4..cbf3521 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -37,6 +37,7 @@ #include <linux/kernel_stat.h> #include <linux/personality.h> #include <linux/random.h> +#include <linux/hw_breakpoint.h> #include <asm/pgtable.h> #include <asm/uaccess.h> @@ -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 */ } /* |