sh: tracing: Use the DWARF unwinder for CALLER_ADDRx

The major reason for implementing the DWARF unwinder in the first place
was so that we could stop using __builtin_return_address(n), which
doesn't work on SH for n > 0.

Signed-off-by: Matt Fleming <matt@console-pimps.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/arch/sh/include/asm/ftrace.h b/arch/sh/include/asm/ftrace.h
index 12f3a31f20af..5ea9030725c0 100644
--- a/arch/sh/include/asm/ftrace.h
+++ b/arch/sh/include/asm/ftrace.h
@@ -32,6 +32,53 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
         return addr;
 }
 
+
+#ifdef CONFIG_DWARF_UNWINDER
+#include <asm/dwarf.h>
+
+#define HAVE_ARCH_CALLER_ADDR
+
+static inline unsigned long dwarf_return_address(int depth)
+{
+        struct dwarf_frame *frame;
+        unsigned long ra;
+        int i;
+
+        for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
+                struct dwarf_frame *tmp;
+
+                tmp = dwarf_unwind_stack(ra, frame);
+
+                if (frame)
+                        dwarf_free_frame(frame);
+
+                frame = tmp;
+
+                if (!frame || !frame->return_addr)
+                        break;
+
+                ra = frame->return_addr;
+        }
+
+        /* Failed to unwind the stack to the specified depth. */
+        WARN_ON(i != depth + 1);
+
+        if (frame)
+                dwarf_free_frame(frame);
+
+        return ra;
+}
+
+#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
+#define CALLER_ADDR1 dwarf_return_address(1)
+#define CALLER_ADDR2 dwarf_return_address(2)
+#define CALLER_ADDR3 dwarf_return_address(3)
+#define CALLER_ADDR4 dwarf_return_address(4)
+#define CALLER_ADDR5 dwarf_return_address(5)
+#define CALLER_ADDR6 dwarf_return_address(6)
+
+#endif /* CONFIG_DWARF_UNWINDER */
+
 #endif /* __ASSEMBLY__ */
 #endif /* CONFIG_FUNCTION_TRACER */