rebased unwind_branch on top of current master

1 files changed, 31 insertions, 6 deletions

diff --git a/runtime/stack-x86_64.c b/runtime/stack-x86_64.c
index 186b2ad4..3ba99201 100644
--- a/runtime/stack-x86_64.c
+++ b/runtime/stack-x86_64.c
@@ -1,6 +1,6 @@
 /* -*- linux-c -*-
  * x86_64 stack tracing functions
- * Copyright (C) 2005, 2006, 2007 Red Hat Inc.
+ * Copyright (C) 2005-2008 Red Hat Inc.
  *
  * This file is part of systemtap, and is free software.  You can
  * redistribute it and/or modify it under the terms of the GNU General
@@ -8,13 +8,38 @@
  * later version.
  */
 
-static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels)
+// todo: don't use unwinder  for kernel if CONFIG_FRAME
+
+/* DWARF unwinder failed.  Just dump intereting addresses on kernel stack. */
+static void _stp_stack_print_fallback(unsigned long stack, int verbose)
 {
-	unsigned long *stack = (unsigned long *)REG_SP(regs);
 	unsigned long addr;
 
-	while ((long)stack & (THREAD_SIZE-1)) {
-		addr = *stack++;
-		_stp_func_print(addr, verbose, 1);
+	while (stack & (THREAD_SIZE - 1)) {
+		if (unlikely(__stp_get_user(addr, (unsigned long *)stack))) {
+			/* cannot access stack.  give up. */
+			return;
+		}
+		_stp_func_print(addr, verbose, 0);
+		stack++;
+	}
+}
+
+static void __stp_stack_print(struct pt_regs *regs, int verbose, int levels)
+{
+	struct unwind_frame_info info;
+	arch_unw_init_frame_info(&info, regs);
+
+	/* we haven't actually executed the instruction at the IP yet. */
+	UNW_PC(&info) -= 1;
+
+	while (!arch_unw_user_mode(&info)) {
+		int ret = unwind(&info);
+		dbug_unwind(1, "ret=%d PC=%lx\n", ret, UNW_PC(&info));
+		if (ret < 0) {
+			_stp_stack_print_fallback(UNW_SP(&info), verbose);
+			break;
+		}
+		_stp_func_print(UNW_PC(&info), verbose, 1);
 	}
 }