sparc64: Fix stack dumping and tracing when function graph is enabled.

Like x86, when the function graph tracer is enabled, emit the ftrace
stub as well as the program counter it will be transformed back into.

We duplicate a lot of similar stack walking logic in 3 or 4 spots, so
eventually we should consolidate things like x86 does.

Thanks to Frederic Weisbecker for pointing this out.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index e2771939341..34ce49f80ea 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -14,6 +14,7 @@
 
 #include <linux/perf_event.h>
 #include <linux/kprobes.h>
+#include <linux/ftrace.h>
 #include <linux/kernel.h>
 #include <linux/kdebug.h>
 #include <linux/mutex.h>
@@ -1276,6 +1277,9 @@ static void perf_callchain_kernel(struct pt_regs *regs,
                                   struct perf_callchain_entry *entry)
 {
         unsigned long ksp, fp;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        int graph = 0;
+#endif
 
         callchain_store(entry, PERF_CONTEXT_KERNEL);
         callchain_store(entry, regs->tpc);
@@ -1303,6 +1307,16 @@ static void perf_callchain_kernel(struct pt_regs *regs,
                         fp = (unsigned long)sf->fp + STACK_BIAS;
                 }
                 callchain_store(entry, pc);
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+                if ((pc + 8UL) == (unsigned long) &return_to_handler) {
+                        int index = current->curr_ret_stack;
+                        if (current->ret_stack && index >= graph) {
+                                pc = current->ret_stack[index - graph].ret;
+                                callchain_store(entry, pc);
+                                graph++;
+                        }
+                }
+#endif
         } while (entry->nr < PERF_MAX_STACK_DEPTH);
 }