nptl: Move stack list variables into _rtld_global

Now __thread_gscope_wait (the function behind THREAD_GSCOPE_WAIT,
formerly __wait_lookup_done) can be implemented directly in ld.so,
eliminating the unprotected GL (dl_wait_lookup_done) function
pointer.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

7 files changed, 70 insertions, 13 deletions

diff --git a/nptl_db/structs.def b/nptl_db/structs.def
index 472e900..2ca3359 100644
--- a/nptl_db/structs.def
+++ b/nptl_db/structs.def
@@ -69,8 +69,6 @@ DB_STRUCT (td_eventbuf_t)
 DB_STRUCT_FIELD (td_eventbuf_t, eventnum)
 DB_STRUCT_FIELD (td_eventbuf_t, eventdata)
 
-DB_SYMBOL (stack_used)
-DB_SYMBOL (__stack_user)
 DB_SYMBOL (nptl_version)
 DB_FUNCTION (__nptl_create_event)
 DB_FUNCTION (__nptl_death_event)
@@ -106,6 +104,8 @@ DB_STRUCT (rtld_global)
 DB_RTLD_VARIABLE (_rtld_global)
 #endif
 DB_RTLD_GLOBAL_FIELD (dl_tls_dtv_slotinfo_list)
+DB_RTLD_GLOBAL_FIELD (dl_stack_user)
+DB_RTLD_GLOBAL_FIELD (dl_stack_used)
 
 DB_STRUCT (dtv_slotinfo_list)
 DB_STRUCT_FIELD (dtv_slotinfo_list, len)
diff --git a/nptl_db/td_init.c b/nptl_db/td_init.c
index 86773dc..79a1f90 100644
--- a/nptl_db/td_init.c
+++ b/nptl_db/td_init.c
@@ -29,3 +29,17 @@ td_init (void)
   LOG ("td_init");
   return TD_OK;
 }
+
+bool
+__td_ta_rtld_global (td_thragent_t *ta)
+{
+  if (ta->ta_addr__rtld_global == 0
+      && td_mod_lookup (ta->ph, LD_SO, SYM__rtld_global,
+                        &ta->ta_addr__rtld_global) != PS_OK)
+    {
+      ta->ta_addr__rtld_global = (void*)-1;
+      return false;
+    }
+  else
+    return ta->ta_addr__rtld_global != (void*)-1;
+}
diff --git a/nptl_db/td_ta_map_lwp2thr.c b/nptl_db/td_ta_map_lwp2thr.c
index d04d4be..81ff488 100644
--- a/nptl_db/td_ta_map_lwp2thr.c
+++ b/nptl_db/td_ta_map_lwp2thr.c
@@ -187,7 +187,7 @@ td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
      fake a special descriptor for the initial thread.  */
 
   psaddr_t list;
-  td_err_e err = DB_GET_SYMBOL (list, ta, __stack_user);
+  td_err_e err = __td_ta_stack_user (ta, &list);
   if (err != TD_OK)
     return err;
 
diff --git a/nptl_db/td_ta_thr_iter.c b/nptl_db/td_ta_thr_iter.c
index d59782b..e406bcb 100644
--- a/nptl_db/td_ta_thr_iter.c
+++ b/nptl_db/td_ta_thr_iter.c
@@ -133,14 +133,14 @@ td_ta_thr_iter (const td_thragent_t *ta_arg, td_thr_iter_f *callback,
      have to iterate over both lists separately.  We start with the
      list of threads with user-defined stacks.  */
 
-  err = DB_GET_SYMBOL (list, ta, __stack_user);
+  err = __td_ta_stack_user (ta, &list);
   if (err == TD_OK)
     err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
 			       list, true);
 
   /* And the threads with stacks allocated by the implementation.  */
   if (err == TD_OK)
-    err = DB_GET_SYMBOL (list, ta, stack_used);
+    err = __td_ta_stack_used (ta, &list);
   if (err == TD_OK)
     err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
 			       list, false);
diff --git a/nptl_db/td_thr_tlsbase.c b/nptl_db/td_thr_tlsbase.c
index 8198934..eeba0a0 100644
--- a/nptl_db/td_thr_tlsbase.c
+++ b/nptl_db/td_thr_tlsbase.c
@@ -28,12 +28,7 @@ dtv_slotinfo_list (td_thragent_t *ta,
   td_err_e err;
   psaddr_t head;
 
-  if (ta->ta_addr__rtld_global == 0
-      && td_mod_lookup (ta->ph, LD_SO, SYM__rtld_global,
-			&ta->ta_addr__rtld_global) != PS_OK)
-    ta->ta_addr__rtld_global = (void*)-1;
-
-  if (ta->ta_addr__rtld_global != (void*)-1)
+  if (__td_ta_rtld_global (ta))
     {
       err = DB_GET_FIELD (head, ta, ta->ta_addr__rtld_global,
 			  rtld_global, _dl_tls_dtv_slotinfo_list, 0);
diff --git a/nptl_db/td_thr_validate.c b/nptl_db/td_thr_validate.c
index c709c5e..d2f4107 100644
--- a/nptl_db/td_thr_validate.c
+++ b/nptl_db/td_thr_validate.c
@@ -20,6 +20,41 @@
 #include "thread_dbP.h"
 #include <stdbool.h>
 
+td_err_e
+__td_ta_stack_user (td_thragent_t *ta, psaddr_t *plist)
+{
+  if (__td_ta_rtld_global (ta))
+    return DB_GET_FIELD_ADDRESS (*plist, ta, ta->ta_addr__rtld_global,
+				 rtld_global, _dl_stack_user, 0);
+  else
+    {
+      if (ta->ta_addr__dl_stack_user == 0
+	  && td_mod_lookup (ta->ph, NULL, SYM__dl_stack_user,
+			    &ta->ta_addr__dl_stack_user) != PS_OK)
+	return TD_ERR;
+      *plist = ta->ta_addr__dl_stack_user;
+      return TD_OK;
+    }
+}
+
+td_err_e
+__td_ta_stack_used (td_thragent_t *ta, psaddr_t *plist)
+{
+
+  if (__td_ta_rtld_global (ta))
+    return DB_GET_FIELD_ADDRESS (*plist, ta, ta->ta_addr__rtld_global,
+				 rtld_global, _dl_stack_used, 0);
+  else
+    {
+      if (ta->ta_addr__dl_stack_used == 0
+	  && td_mod_lookup (ta->ph, NULL, SYM__dl_stack_used,
+			    &ta->ta_addr__dl_stack_used) != PS_OK)
+	return TD_ERR;
+      *plist = ta->ta_addr__dl_stack_used;
+      return TD_OK;
+    }
+}
+
 static td_err_e
 check_thread_list (const td_thrhandle_t *th, psaddr_t head, bool *uninit)
 {
@@ -62,7 +97,7 @@ td_thr_validate (const td_thrhandle_t *th)
 
   /* First check the list with threads using user allocated stacks.  */
   bool uninit = false;
-  err = DB_GET_SYMBOL (list, th->th_ta_p, __stack_user);
+  err = __td_ta_stack_user (th->th_ta_p, &list);
   if (err == TD_OK)
     err = check_thread_list (th, list, &uninit);
 
@@ -70,7 +105,7 @@ td_thr_validate (const td_thrhandle_t *th)
      using implementation allocated stacks.  */
   if (err == TD_NOTHR)
     {
-      err = DB_GET_SYMBOL (list, th->th_ta_p, stack_used);
+      err = __td_ta_stack_used (th->th_ta_p, &list);
       if (err == TD_OK)
 	err = check_thread_list (th, list, &uninit);
 
diff --git a/nptl_db/thread_dbP.h b/nptl_db/thread_dbP.h
index 8a666b8..9574e68 100644
--- a/nptl_db/thread_dbP.h
+++ b/nptl_db/thread_dbP.h
@@ -269,4 +269,17 @@ extern td_err_e _td_check_sizeof (td_thragent_t *ta, uint32_t *sizep,
 extern td_err_e __td_ta_lookup_th_unique (const td_thragent_t *ta,
 					  lwpid_t lwpid, td_thrhandle_t *th);
 
+/* Try to initialize TA->ta_addr__rtld_global.  Return true on
+   success, false on failure (which may be cached).  */
+bool __td_ta_rtld_global (td_thragent_t *ta) attribute_hidden;
+
+/* Obtain the address of the list_t fields _dl_stack_user and
+   _dl_stack_used in _rtld_global, or fall back to the global
+   variables of the same name (to support statically linked
+   programs).  */
+td_err_e __td_ta_stack_user (td_thragent_t *ta, psaddr_t *plist)
+  attribute_hidden;
+td_err_e __td_ta_stack_used (td_thragent_t *ta, psaddr_t *plist)
+  attribute_hidden;
+
 #endif /* thread_dbP.h */