perf_counter: provide generic callchain bits
Provide the generic callchain support bits. If hw_event->callchain is
set the arch specific perf_callchain() function is called upon to
provide a perf_callchain_entry structure filled with the current
callchain.
If it does so, it is added to the overflow output event.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171024.254266860@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index edf5bfb..43083af 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -140,8 +140,9 @@
include_tid : 1, /* include the tid */
mmap : 1, /* include mmap data */
munmap : 1, /* include munmap data */
+ callchain : 1, /* add callchain data */
- __reserved_1 : 52;
+ __reserved_1 : 51;
__u32 extra_config_len;
__u32 __reserved_4;
@@ -219,6 +220,7 @@
PERF_EVENT_OVERFLOW = 1UL << 31,
__PERF_EVENT_IP = 1UL << 30,
__PERF_EVENT_TID = 1UL << 29,
+ __PERF_EVENT_CALLCHAIN = 1UL << 28,
};
#ifdef __KERNEL__
@@ -504,6 +506,15 @@
extern void perf_counter_munmap(unsigned long addr, unsigned long len,
unsigned long pgoff, struct file *file);
+#define MAX_STACK_DEPTH 255
+
+struct perf_callchain_entry {
+ u64 nr;
+ u64 ip[MAX_STACK_DEPTH];
+};
+
+extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
+
#else
static inline void
perf_counter_task_sched_in(struct task_struct *task, int cpu) { }