PR9810: Mostly revert "PR6961: initial sketch: set up dummy pt_regs for non-trap based probes"

5 files changed, 31 insertions, 35 deletions

diff --git a/ChangeLog b/ChangeLog
index 8c8728b1..46046680 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-02-03  Frank Ch. Eigler  <fche@elastic.org>
+
+	PR6961/9810.
+	* tapsets.cxx (common_probe_entryfn_prologue): Revert.
+	* translate.cxx (emit_common_header): Revert.
+
 2009-02-03  Dave Brolley  <brolley@redhat.com>
 
 	* NEWS: Update status of client/server.
diff --git a/tapset/ChangeLog b/tapset/ChangeLog
index da184191..1a7df352 100644
--- a/tapset/ChangeLog
+++ b/tapset/ChangeLog
@@ -1,3 +1,8 @@
+2009-02-03  Frank Ch. Eigler  <fche@elastic.org>
+
+	PR 6961/9810.
+	* context-unwind.stp (print_backtrace, backtrace): Revert.
+
 2009-01-06  Frank Ch. Eigler  <fche@elastic.org>
 
 	PR 9699.
diff --git a/tapset/context-unwind.stp b/tapset/context-unwind.stp
index 4c5ed34b..a0836ed6 100644
--- a/tapset/context-unwind.stp
+++ b/tapset/context-unwind.stp
@@ -23,10 +23,11 @@
  *  except that deeper stack nesting may be supported.  Return nothing.
  */
 function print_backtrace () %{
-	if (! CONTEXT->regs)
-                WARN_ON (! CONTEXT->regs);
-        else
-                _stp_stack_print(CONTEXT->regs, 1, CONTEXT->pi, MAXTRACE);
+	if (CONTEXT->regs) {
+		_stp_stack_print(CONTEXT->regs, 1, CONTEXT->pi, MAXTRACE);
+	} else {
+		_stp_printf("Systemtap probe: %s\n", CONTEXT->probe_point);
+	}
 %}
 
 /**
@@ -36,10 +37,10 @@ function print_backtrace () %{
  *  stack.  It may be truncated due to maximum string length.
  */
 function backtrace:string () %{ /* pure */
-	if (! CONTEXT->regs)
-                WARN_ON (! CONTEXT->regs);
-        else
-                _stp_stack_snprint (THIS->__retvalue, MAXSTRINGLEN, CONTEXT->regs, 0, CONTEXT->pi, MAXTRACE);
+	if (CONTEXT->regs)
+		_stp_stack_snprint (THIS->__retvalue, MAXSTRINGLEN, CONTEXT->regs, 0, CONTEXT->pi, MAXTRACE);
+	else 
+		strlcpy (THIS->__retvalue, "", MAXSTRINGLEN);
 %}
 
 /**
diff --git a/tapsets.cxx b/tapsets.cxx
index 86e4a1e3..c8742fbd 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -159,8 +159,7 @@ be_derived_probe::join_group (systemtap_session& s)
 void
 common_probe_entryfn_prologue (translator_output* o, string statestr,
 			       bool overload_processing = true,
-                               bool interruptible = true,
-                               bool fakeregs = false)
+                               bool interruptible = true)
 {
   o->newline() << "struct context* __restrict__ c;";
   if (! interruptible)
@@ -216,6 +215,7 @@ common_probe_entryfn_prologue (translator_output* o, string statestr,
   o->newline() << "c->last_stmt = 0;";
   o->newline() << "c->last_error = 0;";
   o->newline() << "c->nesting = 0;";
+  o->newline() << "c->regs = 0;";
   o->newline() << "c->unwaddr = 0;";
   // reset unwound address cache
   o->newline() << "c->pi = 0;";
@@ -240,20 +240,6 @@ common_probe_entryfn_prologue (translator_output* o, string statestr,
   o->newline() << "c->cycles_base = 0;";
   o->newline() << "#endif";
   */
-
-  /* PR6961: Let's prep a bare-bones pt_regs struct, just in case our
-     kind of probe point does not supply one. */
-  if (fakeregs)
-    {
-      o->newline() << "#ifdef STP_NEED_UNWIND_DATA";
-      o->newline() << "memset (& c->regs_buffer, 0, sizeof (c->regs_buffer));";
-      o->newline() << "REG_IP((& c->regs_buffer)) = (unsigned long)__builtin_return_address (0);";
-      o->newline() << "REG_SP((& c->regs_buffer)) = (unsigned long)& c;";
-      o->newline() << "c->regs = & c->regs_buffer;";
-      o->newline() << "#endif";
-    }
-  else
-    o->newline() << "c->regs = 0;";
 }
 
 
@@ -352,7 +338,7 @@ be_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline() << "/* ---- begin/end probes ---- */";
   s.op->newline() << "static void enter_begin_probe (void (*fn)(struct context*), const char* pp) {";
   s.op->indent(1);
-  common_probe_entryfn_prologue (s.op, "STAP_SESSION_STARTING", false, true, true);
+  common_probe_entryfn_prologue (s.op, "STAP_SESSION_STARTING", false, true);
   s.op->newline() << "c->probe_point = pp;";
   s.op->newline() << "(*fn) (c);";
   common_probe_entryfn_epilogue (s.op, false, true);
@@ -360,7 +346,7 @@ be_derived_probe_group::emit_module_decls (systemtap_session& s)
 
   s.op->newline() << "static void enter_end_probe (void (*fn)(struct context*), const char* pp) {";
   s.op->indent(1);
-  common_probe_entryfn_prologue (s.op, "STAP_SESSION_STOPPING", false, true, true);
+  common_probe_entryfn_prologue (s.op, "STAP_SESSION_STOPPING", false, true);
   s.op->newline() << "c->probe_point = pp;";
   s.op->newline() << "(*fn) (c);";
   common_probe_entryfn_epilogue (s.op, false, true);
@@ -368,7 +354,7 @@ be_derived_probe_group::emit_module_decls (systemtap_session& s)
 
   s.op->newline() << "static void enter_error_probe (void (*fn)(struct context*), const char* pp) {";
   s.op->indent(1);
-  common_probe_entryfn_prologue (s.op, "STAP_SESSION_ERROR", false, true, true);
+  common_probe_entryfn_prologue (s.op, "STAP_SESSION_ERROR", false, true);
   s.op->newline() << "c->probe_point = pp;";
   s.op->newline() << "(*fn) (c);";
   common_probe_entryfn_epilogue (s.op, false, true);
@@ -6699,7 +6685,7 @@ utrace_derived_probe_group::emit_module_decls (systemtap_session& s)
       s.op->newline() << "static void stap_utrace_probe_handler(struct task_struct *tsk, struct stap_utrace_probe *p) {";
       s.op->indent(1);
 
-      common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", true, true, true);
+      common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING");
       s.op->newline() << "c->probe_point = p->pp;";
 
       // call probe function
@@ -7553,7 +7539,7 @@ timer_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->line() << ");";
   s.op->newline(-1) << "{";
   s.op->indent(1);
-  common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", true, true, true);
+  common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING");
   s.op->newline() << "c->probe_point = stp->pp;";
   s.op->newline() << "(*stp->ph) (c);";
   common_probe_entryfn_epilogue (s.op);
@@ -7932,7 +7918,7 @@ procfs_derived_probe_group::emit_module_decls (systemtap_session& s)
       s.op->newline() << "int bytes = 0;";
       s.op->newline() << "string_t strdata = {'\\0'};";
 
-      common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", true, true, true);
+      common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING");
       s.op->newline() << "c->probe_point = spp->read_pp;";
 
       s.op->newline() << "if (c->data == NULL)";
@@ -7975,7 +7961,7 @@ procfs_derived_probe_group::emit_module_decls (systemtap_session& s)
       s.op->newline(1) << "struct stap_procfs_probe *spp = (struct stap_procfs_probe *)data;";
       s.op->newline() << "string_t strdata = {'\\0'};";
 
-      common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", true, true, true);
+      common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING");
       s.op->newline() << "c->probe_point = spp->write_pp;";
 
       s.op->newline() << "if (count > (MAXSTRINGLEN - 1))";
@@ -8737,7 +8723,7 @@ mark_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline();
   s.op->newline() << "static void enter_marker_probe (void *probe_data, void *call_data, const char *fmt, va_list *args) {";
   s.op->newline(1) << "struct stap_marker_probe *smp = (struct stap_marker_probe *)probe_data;";
-  common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", true, true, true);
+  common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING");
   s.op->newline() << "c->probe_point = smp->pp;";
   s.op->newline() << "c->marker_name = smp->name;";
   s.op->newline() << "c->marker_format = smp->format;";
@@ -8920,7 +8906,6 @@ mark_builder::build(systemtap_session & sess,
 					  it->first, it->second,
 					  base, loc);
 	      finished_results.push_back (dp);
-              sess.unwindsym_modules.insert ("kernel");
 	    }
 	}
     }
@@ -9067,7 +9052,7 @@ hrtimer_derived_probe_group::emit_module_decls (systemtap_session& s)
   s.op->newline(-1) << "}";
   s.op->newline() << "{";
   s.op->indent(1);
-  common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", true, true, true);
+  common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING");
   s.op->newline() << "c->probe_point = stp->pp;";
   s.op->newline() << "(*stp->ph) (c);";
   common_probe_entryfn_epilogue (s.op);
diff --git a/translate.cxx b/translate.cxx
index d3298802..0d430ea3 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -884,7 +884,6 @@ c_unparser::emit_common_header ()
   // While it's 0, execution continues
   // When it's "something", probe code unwinds, _stp_error's, sets error state
   o->newline() << "const char *last_stmt;";
-  o->newline() << "struct pt_regs regs_buffer;"; // reserved for synthetic
   o->newline() << "struct pt_regs *regs;";
   o->newline() << "unsigned long *unwaddr;";
   // unwaddr is caching unwound address in each probe handler on ia64.