set the IP in return probes to the returned-to instruction

It's easily available in kretprobes and uretprobes and is consistent
with the rest of the program state.

* translate.cxx (emit_common_header) : add uretprobe_instance to context.
* tapsets.cxx (common_probe_entryfn_prologue): Initialize ri in
  context to 0.
  (dwarf_derived_probe_group::emit_module_decls): Change IP to return
  address in kretprobes.
  (uprobe_derived_probe_group::emit_module_decls): enter_uretprobe_probe:
  set ri (uretprobe_instance) in context. Change IP to return
  address in uretprobes. Don't emit uprobe include and #define
* runtime/runtime.h : Add includes and #define for uprobes.
* runtime/stack.c (_stp_stack_print, _stp_stack_snprint): Add extra
  argument for uretprobe_instance.
* tapset/context-unwind.stp (print_backtrace, backtrace): Pass NULL
  for uretprobe_instance to _stp_stack_print.
* tapset/ucontext-unwind.stp (print_ubacktrace, ubacktrace): pass
  uretprobe_instance to _stp_stack_print
* testsuite/systemtap.context/uprobe_uaddr.exp : new test for uaddr in
  function probes
* testsuite/systemtap.context/uprobe_uaddr.stp : new file

2 files changed, 19 insertions, 3 deletions

diff --git a/runtime/runtime.h b/runtime/runtime.h
index ba583aeb..a7ee962c 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -31,6 +31,17 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 
+/* If uprobes isn't in the kernel, pull it in from the runtime. */
+#if defined(CONFIG_UPROBES) || defined(CONFIG_UPROBES_MODULE)
+#include <linux/uprobes.h>
+#else
+#include "uprobes/uprobes.h"
+#endif
+#ifndef UPROBES_API_VERSION
+#define UPROBES_API_VERSION 1
+#endif
+
+
 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,15)
 #if !defined (CONFIG_DEBUG_FS)  && !defined (CONFIG_DEBUG_FS_MODULE)
 #error "DebugFS is required and was not found in the kernel."
diff --git a/runtime/stack.c b/runtime/stack.c
index 25dbdbbd..9c23d530 100644
--- a/runtime/stack.c
+++ b/runtime/stack.c
@@ -107,7 +107,7 @@ static void _stp_stack_print_fallback(unsigned long stack, int verbose, int leve
  * @param regs A pointer to the struct pt_regs.
  */
 
-static void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instance *pi, int levels, struct task_struct *tsk)
+static void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe_instance *pi, int levels, struct task_struct *tsk, struct uretprobe_instance *ri)
 {
 	if (verbose) {
 		/* print the current address */
@@ -116,6 +116,11 @@ static void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe
 			_stp_symbol_print((unsigned long)_stp_probe_addr_r(pi));
 			_stp_print("\nReturning to  : ");
 			_stp_symbol_print((unsigned long)_stp_ret_addr_r(pi));
+                } else if (ri) {
+                        _stp_print("Returning from: ");
+                        _stp_usymbol_print(ri->rp->u.vaddr, tsk);
+			_stp_print("\nReturning to  : ");
+                        _stp_usymbol_print(ri->ret_addr, tsk);
 		} else {
 			_stp_print_char(' ');
 			if (tsk)
@@ -138,14 +143,14 @@ static void _stp_stack_print(struct pt_regs *regs, int verbose, struct kretprobe
  * @param regs A pointer to the struct pt_regs.
  * @returns void
  */
-static void _stp_stack_snprint(char *str, int size, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi, int levels, struct task_struct *tsk)
+static void _stp_stack_snprint(char *str, int size, struct pt_regs *regs, int verbose, struct kretprobe_instance *pi, int levels, struct task_struct *tsk, struct uretprobe_instance *ri)
 {
 	/* To get a string, we use a simple trick. First flush the print buffer, */
 	/* then call _stp_stack_print, then copy the result into the output string  */
 	/* and clear the print buffer. */
 	_stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id());
 	_stp_print_flush();
-	_stp_stack_print(regs, verbose, pi, levels, tsk);
+	_stp_stack_print(regs, verbose, pi, levels, tsk, ri);
 	strlcpy(str, pb->buf, size < (int)pb->len ? size : (int)pb->len);
 	pb->len = 0;
 }