ARC: perf: Add kernel callchain support

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
index 181baeed4495c23a704f04cae6e9822b5c673537..a6ad1e09e4be13b480f47d7562a0bbd42a7db903 100644 (file)
--- a/arch/arc/kernel/perf_event.c
+++ b/arch/arc/kernel/perf_event.c
@@ -16,6 +16,7 @@
 #include <linux/perf_event.h>
 #include <linux/platform_device.h>
 #include <asm/arcregs.h>
+#include <asm/stacktrace.h>
 
 struct arc_pmu {
        struct pmu      pmu;
@@ -25,6 +26,34 @@ struct arc_pmu {
        int             ev_hw_idx[PERF_COUNT_ARC_HW_MAX];
 };
 
+struct arc_callchain_trace {
+       int depth;
+       void *perf_stuff;
+};
+
+static int callchain_trace(unsigned int addr, void *data)
+{
+       struct arc_callchain_trace *ctrl = data;
+       struct perf_callchain_entry *entry = ctrl->perf_stuff;
+       perf_callchain_store(entry, addr);
+
+       if (ctrl->depth++ < 3)
+               return 0;
+
+       return -1;
+}
+
+void
+perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+       struct arc_callchain_trace ctrl = {
+               .depth = 0,
+               .perf_stuff = entry,
+       };
+
+       arc_unwind_core(NULL, regs, callchain_trace, &ctrl);
+}
+
 static struct arc_pmu *arc_pmu;
 
 /* read counter #idx; note that counter# != event# on ARC! */