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

8 files changed, 117 insertions, 19 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;
 }
diff --git a/tapset/context-unwind.stp b/tapset/context-unwind.stp
index 741031c0..8f35a783 100644
--- a/tapset/context-unwind.stp
+++ b/tapset/context-unwind.stp
@@ -28,7 +28,7 @@
  */
 function print_backtrace () %{
 	if (CONTEXT->regs) {
-		_stp_stack_print(CONTEXT->regs, 1, CONTEXT->pi, MAXTRACE, NULL);
+		_stp_stack_print(CONTEXT->regs, 1, CONTEXT->pi, MAXTRACE, NULL, NULL);
 	} else {
 		_stp_printf("Systemtap probe: %s\n", CONTEXT->probe_point);
 	}
@@ -42,7 +42,7 @@ function print_backtrace () %{
  */
 function backtrace:string () %{ /* pure */
 	if (CONTEXT->regs)
-		_stp_stack_snprint (THIS->__retvalue, MAXSTRINGLEN, CONTEXT->regs, 0, CONTEXT->pi, MAXTRACE, NULL);
+		_stp_stack_snprint (THIS->__retvalue, MAXSTRINGLEN, CONTEXT->regs, 0, CONTEXT->pi, MAXTRACE, NULL, NULL);
 	else 
 		strlcpy (THIS->__retvalue, "", MAXSTRINGLEN);
 %}
diff --git a/tapset/ucontext-unwind.stp b/tapset/ucontext-unwind.stp
index d699e588..e0d883b8 100644
--- a/tapset/ucontext-unwind.stp
+++ b/tapset/ucontext-unwind.stp
@@ -28,7 +28,7 @@ function print_ubacktrace () %{ /* unprivileged */
         assert_is_myproc();
 	if (CONTEXT->regs) {
 		_stp_stack_print(CONTEXT->regs, 1, CONTEXT->pi, MAXTRACE,
-				 current);
+				 current, CONTEXT->ri);
 	} else {
 		_stp_printf("Systemtap probe: %s\n", CONTEXT->probe_point);
 	}
@@ -47,7 +47,7 @@ function ubacktrace:string () %{ /* pure */ /* unprivileged */
 	if (CONTEXT->regs)
 		_stp_stack_snprint (THIS->__retvalue, MAXSTRINGLEN,
 				    CONTEXT->regs, 0, CONTEXT->pi, MAXTRACE,
-				    current);
+				    current, CONTEXT->ri);
 	else 
 		strlcpy (THIS->__retvalue, "", MAXSTRINGLEN);
 %}
diff --git a/tapsets.cxx b/tapsets.cxx
index cf6f97ef..5729757b 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -142,6 +142,7 @@ common_probe_entryfn_prologue (translator_output* o, string statestr,
   o->newline() << "#ifdef STP_TIMING";
   o->newline() << "c->statp = 0;";
   o->newline() << "#endif";
+  o->newline() << "c->ri = 0;";
   // NB: The following would actually be incorrect.
   // That's because cycles_sum/cycles_base values are supposed to survive
   // between consecutive probes.  Periodically (STP_OVERLOAD_INTERVAL
@@ -3373,8 +3374,15 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long kprobes_ip = REG_IP(c->regs);";
+  s.op->newline() << "if (entry) {";
+  s.op->indent(1);
   s.op->newline() << "SET_REG_IP(regs, (unsigned long) inst->rp->kp.addr);";
-  s.op->newline() << "(entry ? sdp->entry_ph : sdp->ph) (c);";
+  s.op->newline() << "(sdp->entry_ph) (c);";
+  s.op->newline(-1) << "} else {";
+  s.op->indent(1);
+  s.op->newline() << "SET_REG_IP(regs, (unsigned long)inst->ret_addr);";
+  s.op->newline() << "(sdp->ph) (c);";
+  s.op->newline(-1) << "}";
   s.op->newline() << "SET_REG_IP(regs, kprobes_ip);";
   s.op->newline(-1) << "}";
 
@@ -4569,16 +4577,6 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
   if (probes.empty()) return;
   s.op->newline() << "/* ---- user probes ---- */";
 
-  // If uprobes isn't in the kernel, pull it in from the runtime.
-  s.op->newline() << "#if defined(CONFIG_UPROBES) || defined(CONFIG_UPROBES_MODULE)";
-  s.op->newline() << "#include <linux/uprobes.h>";
-  s.op->newline() << "#else";
-  s.op->newline() << "#include \"uprobes/uprobes.h\"";
-  s.op->newline() << "#endif";
-  s.op->newline() << "#ifndef UPROBES_API_VERSION";
-  s.op->newline() << "#define UPROBES_API_VERSION 1";
-  s.op->newline() << "#endif";
-
   // We'll probably need at least this many:
   unsigned minuprobes = probes.size();
   // .. but we don't want so many that .bss is inflated (PR10507):
@@ -4723,6 +4721,7 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline(1) << "struct stap_uprobe *sup = container_of(inst->rp, struct stap_uprobe, urp);";
   s.op->newline() << "const struct stap_uprobe_spec *sups = &stap_uprobe_specs [sup->spec_index];";
   common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", "sups->pp");
+  s.op->newline() << "c->ri = inst;";
   s.op->newline() << "if (sup->spec_index < 0 ||"
                   << "sup->spec_index >= " << probes.size() << ") return;"; // XXX: should not happen
   // XXX: kretprobes saves "c->pi = inst;" too
@@ -4734,7 +4733,7 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline() << "{";
   s.op->indent(1);
   s.op->newline() << "unsigned long uprobes_ip = REG_IP(c->regs);";
-  s.op->newline() << "SET_REG_IP(regs, inst->rp->u.vaddr);";
+  s.op->newline() << "SET_REG_IP(regs, inst->ret_addr);";
   s.op->newline() << "(*sups->ph) (c);";
   s.op->newline() << "SET_REG_IP(regs, uprobes_ip);";
   s.op->newline(-1) << "}";
diff --git a/testsuite/systemtap.context/uprobe_uaddr.exp b/testsuite/systemtap.context/uprobe_uaddr.exp
new file mode 100644
index 00000000..521dfa57
--- /dev/null
+++ b/testsuite/systemtap.context/uprobe_uaddr.exp
@@ -0,0 +1,58 @@
+# Tests uaddr in function call and return probes. For a call probe we
+# expect the address to be in the function; for a return probe it
+# should be in the function's caller.
+
+set test "uprobe_uaddr"
+
+# Only run on make installcheck and utrace present.
+if {! [installtest_p]} { untested "$test"; return }
+if {! [utrace_p]} { untested "$test"; return }
+
+set testpath  "$srcdir/$subdir"
+set testsrc   "$testpath/uprobe_stmt_num.c"
+set testexe   "[pwd]/$test"
+
+# We want debug info and no optimization (every line counts).
+set testflags "additional_flags=-g additional_flags=-O0"
+set teststp   "$testpath/$test.stp"
+
+set res [target_compile $testsrc $testexe executable $testflags]
+if { $res != "" } {
+    verbose "target_compile failed: $res" 2
+    fail "unable to compile $testsrc"
+    return
+}
+
+set cmd [concat stap -c $testexe $teststp]
+send_log "cmd: $cmd\n"
+catch {eval exec $cmd} output
+send_log "cmd output:\n $output\n"
+
+set output_lines [split $output "\n"]
+
+set lines [llength $output_lines]
+if { $lines == 6 } {
+    pass "$test"
+} else {
+    fail "$test ($lines)"
+}
+
+set result_funcs [list "main *" "func *" "func2 *" "func *" "main *"]
+
+foreach expected $result_funcs output $output_lines {
+    if {$expected != ""} {
+        if [string match $expected $output] {
+            pass "$test"
+        } else {
+            fail "$test $output"
+        }
+    } else {
+        break;
+    }
+}
+
+if [string match "main *" [lindex $output_lines 5]] {
+    fail "$test return from main"
+} else {
+    pass "$test"
+}
diff --git a/testsuite/systemtap.context/uprobe_uaddr.stp b/testsuite/systemtap.context/uprobe_uaddr.stp
new file mode 100644
index 00000000..1528e559
--- /dev/null
+++ b/testsuite/systemtap.context/uprobe_uaddr.stp
@@ -0,0 +1,24 @@
+probe process("uprobe_uaddr").function("main").call {
+    println(usymdata(uaddr()))
+}
+
+probe process("uprobe_uaddr").function("main").return {
+    println(usymdata(uaddr()))
+}
+
+probe process("uprobe_uaddr").function("func").call {
+    println(usymdata(uaddr()))
+}
+
+probe process("uprobe_uaddr").function("func").return {
+    println(usymdata(uaddr()))
+}
+
+probe process("uprobe_uaddr").function("func2").call {
+    println(usymdata(uaddr()))
+}
+
+probe process("uprobe_uaddr").function("func2").return {
+    println(usymdata(uaddr()))
+}
+
diff --git a/translate.cxx b/translate.cxx
index aca0d868..e6c8cde9 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -905,6 +905,7 @@ c_unparser::emit_common_header ()
   o->newline() << "cycles_t cycles_base;";
   o->newline() << "cycles_t cycles_sum;";
   o->newline() << "#endif";
+  o->newline() << "struct uretprobe_instance *ri;";
 
 
   // PR10516: probe locals