[PATCH v4 6/7] Add support for LWP-based threads on FreeBSD.

[PATCH v4 6/7] Add support for LWP-based threads on FreeBSD.

[John Baldwin]

Older versions of FreeBSD supported userland threading via a pure
user-space threading library (N threads scheduled on 1 process) and
a N:M model (N threads scheduled on M LWPs).  However, modern FreeBSD
versions only support a M:M threading model where each user thread is
backed by a dedicated LWP.  This thread target only supports this
threading model.  It also uses ptrace to query and alter LWP state
directly rather than using libthread_db to simplify the implementation.

FreeBSD recently gained support for reporting LWP events (birth and death
of LWPs).  GDB will use LWP events when present.  For older systems it
fetches the list of LWPs in the to_update_thread_list target op to update
the list of threads on each stop.

This target supports scheduler locking by using ptrace to suspend
individual LWPs as necessary before resuming a process.

gdb/ChangeLog:

	* configure.ac: Check for support for LWP names on FreeBSD.
	* fbsd-nat.c [PT_LWPINFO] New variable debug_fbsd_lwp.
	[TDP_RFPPWAIT || HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME]
	(fbsd_fetch_kinfo_proc): Move function earlier.
	[PT_LWPINFO] (fbsd_thread_alive): New function.
	[PT_LWPINFO] (fbsd_pid_to_str): New function.
	[HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME] (fbsd_thread_name): New function.
	[PT_LWP_EVENTS] (fbsd_enable_lwp_events): New function.
	[PT_LWPINFO] (fbsd_add_threads): New function.
	[PT_LWPINFO] (fbsd_update_thread_list): New function.
	[PT_LWPINFO] New variable super_resume.
	[PT_LWPINFO] (resume_one_thread_cb): New function.
	[PT_LWPINFO] (resume_all_threads_cb): New function.
	[PT_LWPINFO] (fbsd_resume): New function.
	(fbsd_remember_child): Save full ptid instead of plain pid.
	(fbsd_is_child_pending): Return ptid of saved child process.
	(fbsd_wait): Include lwp in returned ptid and switch to LWP ptid on
	first stop.
	[PT_LWP_EVENTS] Handle LWP events.
	[TDP_RFPPWAIT] Include LWP in child ptid.
	(fbsd_post_startup_inferior) [PT_LWP_EVENTS]: Enable LWP events.
	(fbsd_post_attach) [PT_LWP_EVENTS]: Enable LWP events.
	Add threads for existing processes.
	(fbsd_nat_add_target) [PT_LWPINFO]: Set "to_thread_alive" to
	"fbsd_thread_alive".
	Set "to_pid_to_str" to "fbsd_pid_to_str".
	[HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME]: Set "to_thread_name" to
	"fbsd_thread_name".
	[PT_LWPINFO]: Set "to_update_thread_list" to "fbsd_update_thread_list".
	Set "to_has_thread_control" to "tc_schedlock".
	Set "to_resume" to "fbsd_resume".
	(_initialize_fbsd_nat): New function.
	* configure: Regenerate.
	* config.in: Regenerate.

gdb/doc/ChangeLog:

	* gdb.texinfo (Debugging Output): Document "set/show debug fbsd-lwp".
---
 gdb/ChangeLog       |  37 +++++
 gdb/NEWS            |   6 +
 gdb/config.in       |   3 +
 gdb/configure       |  16 ++
 gdb/configure.ac    |   7 +
 gdb/doc/ChangeLog   |   4 +
 gdb/doc/gdb.texinfo |   5 +
 gdb/fbsd-nat.c      | 423 ++++++++++++++++++++++++++++++++++++++++++++++++----
 8 files changed, 469 insertions(+), 32 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 5361932..ad81391 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,42 @@
 2016-01-16  John Baldwin  <jhb@FreeBSD.org>
 
+	* configure.ac: Check for support for LWP names on FreeBSD.
+	* fbsd-nat.c [PT_LWPINFO] New variable debug_fbsd_lwp.
+	[TDP_RFPPWAIT || HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME]
+	(fbsd_fetch_kinfo_proc): Move function earlier.
+	[PT_LWPINFO] (fbsd_thread_alive): New function.
+	[PT_LWPINFO] (fbsd_pid_to_str): New function.
+	[HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME] (fbsd_thread_name): New function.
+	[PT_LWP_EVENTS] (fbsd_enable_lwp_events): New function.
+	[PT_LWPINFO] (fbsd_add_threads): New function.
+	[PT_LWPINFO] (fbsd_update_thread_list): New function.
+	[PT_LWPINFO] New variable super_resume.
+	[PT_LWPINFO] (resume_one_thread_cb): New function.
+	[PT_LWPINFO] (resume_all_threads_cb): New function.
+	[PT_LWPINFO] (fbsd_resume): New function.
+	(fbsd_remember_child): Save full ptid instead of plain pid.
+	(fbsd_is_child_pending): Return ptid of saved child process.
+	(fbsd_wait): Include lwp in returned ptid and switch to LWP ptid on
+	first stop.
+	[PT_LWP_EVENTS] Handle LWP events.
+	[TDP_RFPPWAIT] Include LWP in child ptid.
+	(fbsd_post_startup_inferior) [PT_LWP_EVENTS]: Enable LWP events.
+	(fbsd_post_attach) [PT_LWP_EVENTS]: Enable LWP events.
+	Add threads for existing processes.
+	(fbsd_nat_add_target) [PT_LWPINFO]: Set "to_thread_alive" to
+	"fbsd_thread_alive".
+	Set "to_pid_to_str" to "fbsd_pid_to_str".
+	[HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME]: Set "to_thread_name" to
+	"fbsd_thread_name".
+	[PT_LWPINFO]: Set "to_update_thread_list" to "fbsd_update_thread_list".
+	Set "to_has_thread_control" to "tc_schedlock".
+	Set "to_resume" to "fbsd_resume".
+	(_initialize_fbsd_nat): New function.
+	* configure: Regenerate.
+	* config.in: Regenerate.
+
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
 	* amd64bsd-nat.c (amd64bsd_fetch_inferior_registers): Use
 	get_ptrace_pid.
 	(amd64bsd_store_inferior_registers): Use get_ptrace_pid.
diff --git a/gdb/NEWS b/gdb/NEWS
index 9d3a47c..4f276a1 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -3,6 +3,8 @@
 
 *** Changes since GDB 7.10
 
+* GDB now supports debugging kernel-based threads on FreeBSD.
+
 * Per-inferior thread numbers
 
   Thread numbers are now per inferior instead of global.  If you're
@@ -93,6 +95,10 @@ set debug bfd-cache
 show debug bfd-cache
   Control display of debugging info regarding bfd caching.
 
+set debug fbsd-lwp
+show debug fbsd-lwp
+  Control display of debugging info regarding FreeBSD threads.
+
 set remote multiprocess-extensions-packet
 show remote multiprocess-extensions-packet
   Set/show the use of the remote protocol multiprocess extensions.
diff --git a/gdb/config.in b/gdb/config.in
index 6196fa0..dc9da0a 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -450,6 +450,9 @@
 /* Define to 1 if your system has struct lwp. */
 #undef HAVE_STRUCT_LWP
 
+/* Define to 1 if `struct ptrace_lwpinfo' is a member of `pl_tdname'. */
+#undef HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME
+
 /* Define to 1 if your system has struct reg in <machine/reg.h>. */
 #undef HAVE_STRUCT_REG
 
diff --git a/gdb/configure b/gdb/configure
index 4abedd3..5c2699a 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -12963,6 +12963,22 @@ $as_echo "#define HAVE_PT_GETXMMREGS 1" >>confdefs.h
 
 fi
 
+# See if <sys/ptrace.h> supports LWP names on FreeBSD
+# Older FreeBSD versions don't have the pl_tdname member of
+# `struct ptrace_lwpinfo'.
+ac_fn_c_check_member "$LINENO" "struct ptrace_lwpinfo" "pl_tdname" "ac_cv_member_struct_ptrace_lwpinfo_pl_tdname" "#include <sys/ptrace.h>
+"
+if test "x$ac_cv_member_struct_ptrace_lwpinfo_pl_tdname" = x""yes; then :
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME 1
+_ACEOF
+
+
+fi
+
+
+
 # Detect which type of /proc is in use, such as for Solaris.
 
 if test "${target}" = "${host}"; then
diff --git a/gdb/configure.ac b/gdb/configure.ac
index e2a7e68..e10a523 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1510,6 +1510,13 @@ if test $gdb_cv_have_pt_getxmmregs = yes; then
   [Define if sys/ptrace.h defines the PT_GETXMMREGS request.])
 fi
 
+# See if <sys/ptrace.h> supports LWP names on FreeBSD
+# Older FreeBSD versions don't have the pl_tdname member of
+# `struct ptrace_lwpinfo'.
+AC_CHECK_MEMBERS([struct ptrace_lwpinfo.pl_tdname], [], [],
+                 [#include <sys/ptrace.h>])
+
+
 # Detect which type of /proc is in use, such as for Solaris.
 
 if test "${target}" = "${host}"; then
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index db280b9..48015c6 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
+	* gdb.texinfo (Debugging Output): Document "set/show debug fbsd-lwp".
+
 2016-01-15  Pedro Alves  <palves@redhat.com>
 
 	* gdb.texinfo (Threads) <thread ID lists>: Document star ranges.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a08a196..26ba1e2 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -23594,6 +23594,11 @@ expression parsing.  The default is off.
 @item show debug expression
 Displays the current state of displaying debugging info about
 @value{GDBN} expression parsing.
+@item set debug fbsd-lwp
+@cindex FreeBSD LWP debug messages
+Turns on or off debugging messages from the FreeBSD LWP debug support.
+@item show debug fbsd-lwp
+Show the current state of FreeBSD LWP debugging messages.
 @item set debug frame
 @cindex frame debugging info
 Turns on or off display of @value{GDBN} frame debugging info.  The
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 702e51d..d2ec527 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -22,6 +22,7 @@
 #include "inferior.h"
 #include "regcache.h"
 #include "regset.h"
+#include "gdbcmd.h"
 #include "gdbthread.h"
 #include "gdb_wait.h"
 #include <sys/types.h>
@@ -204,11 +205,283 @@ fbsd_find_memory_regions (struct target_ops *self,
 #endif
 
 #ifdef PT_LWPINFO
+static int debug_fbsd_lwp;
+
 static ptid_t (*super_wait) (struct target_ops *,
 			     ptid_t,
 			     struct target_waitstatus *,
 			     int);
 
+static void
+show_fbsd_lwp_debug (struct ui_file *file, int from_tty,
+		     struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("Debugging of FreeBSD lwp module is %s.\n"), value);
+}
+
+#if defined(TDP_RFPPWAIT) || defined(HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME)
+/* Fetch the external variant of the kernel's internal process
+   structure for the process PID into KP.  */
+
+static void
+fbsd_fetch_kinfo_proc (pid_t pid, struct kinfo_proc *kp)
+{
+  size_t len;
+  int mib[4];
+
+  len = sizeof *kp;
+  mib[0] = CTL_KERN;
+  mib[1] = KERN_PROC;
+  mib[2] = KERN_PROC_PID;
+  mib[3] = pid;
+  if (sysctl (mib, 4, kp, &len, NULL, 0) == -1)
+    perror_with_name (("sysctl"));
+}
+#endif
+
+/*
+  FreeBSD's first thread support was via a "reentrant" version of libc
+  (libc_r) that first shipped in 2.2.7.  This library multiplexed all
+  of the threads in a process onto a single kernel thread.  This
+  library is supported via the bsd-uthread target.
+
+  FreeBSD 5.1 introduced two new threading libraries that made use of
+  multiple kernel threads.  The first (libkse) scheduled M user
+  threads onto N (<= M) kernel threads (LWPs).  The second (libthr)
+  bound each user thread to a dedicated kernel thread.  libkse shipped
+  as the default threading library (libpthread).
+
+  FreeBSD 5.3 added a libthread_db to abstract the interface across
+  the various thread libraries (libc_r, libkse, and libthr).
+
+  FreeBSD 7.0 switched the default threading library from from libkse
+  to libpthread and removed libc_r.
+
+  FreeBSD 8.0 removed libkse and the in-kernel support for it.  The
+  only threading library supported by 8.0 and later is libthr which
+  ties each user thread directly to an LWP.  To simplify the
+  implementation, this target only supports LWP-backed threads using
+  ptrace directly rather than libthread_db.
+
+  FreeBSD 11.0 introduced LWP event reporting via PT_LWP_EVENTS.
+*/
+
+/* Return true if PTID is still active in the inferior.  */
+
+static int
+fbsd_thread_alive (struct target_ops *ops, ptid_t ptid)
+{
+  if (ptid_lwp_p (ptid))
+    {
+      struct ptrace_lwpinfo pl;
+
+      if (ptrace (PT_LWPINFO, ptid_get_lwp (ptid), (caddr_t) &pl, sizeof pl)
+	  == -1)
+	return 0;
+#ifdef PL_FLAG_EXITED
+      if (pl.pl_flags & PL_FLAG_EXITED)
+	return 0;
+#endif
+    }
+
+  return 1;
+}
+
+/* Convert PTID to a string.  Returns the string in a static
+   buffer.  */
+
+static char *
+fbsd_pid_to_str (struct target_ops *ops, ptid_t ptid)
+{
+  lwpid_t lwp;
+
+  lwp = ptid_get_lwp (ptid);
+  if (lwp != 0)
+    {
+      static char buf[64];
+      int pid = ptid_get_pid (ptid);
+
+      xsnprintf (buf, sizeof buf, "process %d, LWP %d", pid, lwp);
+      return buf;
+    }
+
+  return normal_pid_to_str (ptid);
+}
+
+#ifdef HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME
+/* Return the name assigned to a thread by an application.  Returns
+   the string in a static buffer.  */
+
+static const char *
+fbsd_thread_name (struct target_ops *self, struct thread_info *thr)
+{
+  struct ptrace_lwpinfo pl;
+  struct kinfo_proc kp;
+  int pid = ptid_get_pid (thr->ptid);
+  long lwp = ptid_get_lwp (thr->ptid);
+  static char buf[sizeof pl.pl_tdname + 1];
+
+  /* Note that ptrace_lwpinfo returns the process command in pl_tdname
+     if a name has not been set explicitly.  Return a NULL name in
+     that case.  */
+  fbsd_fetch_kinfo_proc (pid, &kp);
+  if (ptrace (PT_LWPINFO, lwp, (caddr_t) &pl, sizeof pl) == -1)
+    perror_with_name (("ptrace"));
+  if (strcmp (kp.ki_comm, pl.pl_tdname) == 0)
+    return NULL;
+  xsnprintf (buf, sizeof buf, "%s", pl.pl_tdname);
+  return buf;
+}
+#endif
+
+#ifdef PT_LWP_EVENTS
+/* Enable LWP events for a specific process.
+
+   To catch LWP events, PT_LWP_EVENTS is set on every traced process.
+   This enables stops on the birth for new LWPs (excluding the "main" LWP)
+   and the death of LWPs (excluding the last LWP in a process).  Note
+   that unlike fork events, the LWP that creates a new LWP does not
+   report an event.  */
+
+static void
+fbsd_enable_lwp_events (pid_t pid)
+{
+  if (ptrace (PT_LWP_EVENTS, pid, (PTRACE_TYPE_ARG3)0, 1) == -1)
+    perror_with_name (("ptrace"));
+}
+#endif
+
+/* Add threads for any new LWPs in a process.
+
+   When LWP events are used, this function is only used to detect existing
+   threads when attaching to a process.  On older systems, this function is
+   called to discover new threads each time the thread list is updated.  */
+
+static void
+fbsd_add_threads (pid_t pid)
+{
+  struct cleanup *cleanup;
+  lwpid_t *lwps;
+  int i, nlwps;
+
+  gdb_assert (!in_thread_list (pid_to_ptid (pid)));
+  nlwps = ptrace (PT_GETNUMLWPS, pid, NULL, 0);
+  if (nlwps == -1)
+    perror_with_name (("ptrace"));
+
+  lwps = XCNEWVEC (lwpid_t, nlwps);
+  cleanup = make_cleanup (xfree, lwps);
+
+  nlwps = ptrace (PT_GETLWPLIST, pid, (caddr_t) lwps, nlwps);
+  if (nlwps == -1)
+    perror_with_name (("ptrace"));
+
+  for (i = 0; i < nlwps; i++)
+    {
+      ptid_t ptid = ptid_build (pid, lwps[i], 0);
+
+      if (!in_thread_list (ptid))
+	{
+#ifdef PT_LWP_EVENTS
+	  struct ptrace_lwpinfo pl;
+
+	  /* Don't add exited threads.  Note that this is only called
+	     when attaching to a multi-threaded process.  */
+	  if (ptrace (PT_LWPINFO, lwps[i], (caddr_t) &pl, sizeof pl) == -1)
+	    perror_with_name (("ptrace"));
+	  if (pl.pl_flags & PL_FLAG_EXITED)
+	    continue;
+#endif
+	  if (debug_fbsd_lwp)
+	    fprintf_unfiltered (gdb_stdlog,
+				"FLWP: adding thread for LWP %u\n",
+				lwps[i]);
+	  add_thread (ptid);
+	}
+    }
+  do_cleanups (cleanup);
+}
+
+/* Implement the "to_update_thread_list" target_ops method.  */
+
+static void
+fbsd_update_thread_list (struct target_ops *ops)
+{
+#ifdef PT_LWP_EVENTS
+  /* With support for thread events, threads are added/deleted from the
+     list as events are reported, so just try deleting exited threads.  */
+  delete_exited_threads ();
+#else
+  prune_threads ();
+
+  fbsd_add_threads (ptid_get_pid (inferior_ptid));
+#endif
+}
+
+static void (*super_resume) (struct target_ops *,
+			     ptid_t,
+			     int,
+			     enum gdb_signal);
+
+static int
+resume_one_thread_cb (struct thread_info *tp, void *data)
+{
+  ptid_t *ptid = data;
+  int request;
+
+  if (ptid_get_pid (tp->ptid) != ptid_get_pid (*ptid))
+    return 0;
+
+  if (ptid_get_lwp (tp->ptid) == ptid_get_lwp (*ptid))
+    request = PT_RESUME;
+  else
+    request = PT_SUSPEND;
+
+  if (ptrace (request, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
+    perror_with_name (("ptrace"));
+  return 0;
+}
+
+static int
+resume_all_threads_cb (struct thread_info *tp, void *data)
+{
+  ptid_t *filter = data;
+
+  if (!ptid_match (tp->ptid, *filter))
+    return 0;
+
+  if (ptrace (PT_RESUME, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
+    perror_with_name (("ptrace"));
+  return 0;
+}
+
+/* Implement the "to_resume" target_ops method.  */
+
+static void
+fbsd_resume (struct target_ops *ops,
+	     ptid_t ptid, int step, enum gdb_signal signo)
+{
+
+  if (debug_fbsd_lwp)
+    fprintf_unfiltered (gdb_stdlog,
+			"FLWP: fbsd_resume for ptid (%d, %ld, %ld)\n",
+			ptid_get_pid (ptid), ptid_get_lwp (ptid),
+			ptid_get_tid (ptid));
+  if (ptid_lwp_p (ptid))
+    {
+      /* If ptid is a specific LWP, suspend all other LWPs in the process.  */
+      iterate_over_threads (resume_one_thread_cb, &ptid);
+    }
+  else
+    {
+      /* If ptid is a wildcard, resume all matching threads (they won't run
+	 until the process is continued however).  */
+      iterate_over_threads (resume_all_threads_cb, &ptid);
+      ptid = inferior_ptid;
+    }
+  super_resume (ops, ptid, step, signo);
+}
+
 #ifdef TDP_RFPPWAIT
 /*
   To catch fork events, PT_FOLLOW_FORK is set on every traced process
@@ -246,7 +519,7 @@ static ptid_t (*super_wait) (struct target_ops *,
 struct fbsd_fork_child_info
 {
   struct fbsd_fork_child_info *next;
-  pid_t child;			/* Pid of new child.  */
+  ptid_t child;			/* Pid of new child.  */
 };
 
 static struct fbsd_fork_child_info *fbsd_pending_children;
@@ -255,7 +528,7 @@ static struct fbsd_fork_child_info *fbsd_pending_children;
    corresponding fork event in the parent.  */
 
 static void
-fbsd_remember_child (pid_t pid)
+fbsd_remember_child (ptid_t pid)
 {
   struct fbsd_fork_child_info *info = XCNEW (struct fbsd_fork_child_info);
 
@@ -265,45 +538,29 @@ fbsd_remember_child (pid_t pid)
 }
 
 /* Check for a previously-recorded new child process event for PID.
-   If one is found, remove it from the list.  */
+   If one is found, remove it from the list and return the PTID.  */
 
-static int
+static ptid_t
 fbsd_is_child_pending (pid_t pid)
 {
   struct fbsd_fork_child_info *info, *prev;
+  ptid_t ptid;
 
   prev = NULL;
   for (info = fbsd_pending_children; info; prev = info, info = info->next)
     {
-      if (info->child == pid)
+      if (ptid_get_pid (info->child) == pid)
 	{
 	  if (prev == NULL)
 	    fbsd_pending_children = info->next;
 	  else
 	    prev->next = info->next;
+	  ptid = info->child;
 	  xfree (info);
-	  return 1;
+	  return ptid;
 	}
     }
-  return 0;
-}
-
-/* Fetch the external variant of the kernel's internal process
-   structure for the process PID into KP.  */
-
-static void
-fbsd_fetch_kinfo_proc (pid_t pid, struct kinfo_proc *kp)
-{
-  size_t len;
-  int mib[4];
-
-  len = sizeof *kp;
-  mib[0] = CTL_KERN;
-  mib[1] = KERN_PROC;
-  mib[2] = KERN_PROC_PID;
-  mib[3] = pid;
-  if (sysctl (mib, 4, kp, &len, NULL, 0) == -1)
-    perror_with_name (("sysctl"));
+  return null_ptid;
 }
 #endif
 
@@ -328,21 +585,83 @@ fbsd_wait (struct target_ops *ops,
 	  int status;
 
 	  pid = ptid_get_pid (wptid);
-	  if (ptrace (PT_LWPINFO, pid, (caddr_t)&pl, sizeof pl) == -1)
+	  if (ptrace (PT_LWPINFO, pid, (caddr_t) &pl, sizeof pl) == -1)
 	    perror_with_name (("ptrace"));
 
+	  wptid = ptid_build (pid, pl.pl_lwpid, 0);
+
+#ifdef PT_LWP_EVENTS
+	  if (pl.pl_flags & PL_FLAG_EXITED)
+	    {
+	      /* If GDB attaches to a multi-threaded process, exiting
+		 threads might be skipped during fbsd_post_attach that
+		 have not yet reported their PL_FLAG_EXITED event.
+		 Ignore EXITED events for an unknown LWP.  */
+	      if (in_thread_list (wptid))
+		{
+		  if (debug_fbsd_lwp)
+		    fprintf_unfiltered (gdb_stdlog,
+					"FLWP: deleting thread for LWP %u\n",
+					pl.pl_lwpid);
+		  if (print_thread_events)
+		    printf_unfiltered (_("[%s exited]\n"), target_pid_to_str
+				       (wptid));
+		  delete_thread (wptid);
+		}
+	      if (ptrace (PT_CONTINUE, pid, (caddr_t) 1, 0) == -1)
+		perror_with_name (("ptrace"));
+	      continue;
+	    }
+#endif
+
+	  /* Switch to an LWP PTID on the first stop in a new process.
+	     This is done after handling PL_FLAG_EXITED to avoid
+	     switching to an exited LWP.  It is done before checking
+	     PL_FLAG_BORN in case the first stop reported after
+	     attaching to an existing process is a PL_FLAG_BORN
+	     event.  */
+	  if (in_thread_list (pid_to_ptid (pid)))
+	    {
+	      if (debug_fbsd_lwp)
+		fprintf_unfiltered (gdb_stdlog,
+				    "FLWP: using LWP %u for first thread\n",
+				    pl.pl_lwpid);
+	      thread_change_ptid (pid_to_ptid (pid), wptid);
+	    }
+
+#ifdef PT_LWP_EVENTS
+	  if (pl.pl_flags & PL_FLAG_BORN)
+	    {
+	      /* If GDB attaches to a multi-threaded process, newborn
+		 threads might be added by fbsd_add_threads that have
+		 not yet reported their PL_FLAG_BORN event.  Ignore
+		 BORN events for an already-known LWP.  */
+	      if (!in_thread_list (wptid))
+		{
+		  if (debug_fbsd_lwp)
+		    fprintf_unfiltered (gdb_stdlog,
+					"FLWP: adding thread for LWP %u\n",
+					pl.pl_lwpid);
+		  add_thread (wptid);
+		}
+	      ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
+	      return wptid;
+	    }
+#endif
+
 #ifdef TDP_RFPPWAIT
 	  if (pl.pl_flags & PL_FLAG_FORKED)
 	    {
 	      struct kinfo_proc kp;
+	      ptid_t child_ptid;
 	      pid_t child;
 
 	      child = pl.pl_child_pid;
 	      ourstatus->kind = TARGET_WAITKIND_FORKED;
-	      ourstatus->value.related_pid = pid_to_ptid (child);
 
 	      /* Make sure the other end of the fork is stopped too.  */
-	      if (!fbsd_is_child_pending (child))
+	      child_ptid = fbsd_is_child_pending (child);
+	      if (ptid_equal (child_ptid, null_ptid))
 		{
 		  pid = waitpid (child, &status, 0);
 		  if (pid == -1)
@@ -354,6 +673,7 @@ fbsd_wait (struct target_ops *ops,
 		    perror_with_name (("ptrace"));
 
 		  gdb_assert (pl.pl_flags & PL_FLAG_CHILD);
+		  child_ptid = ptid_build (child, pl.pl_lwpid, 0);
 		}
 
 	      /* For vfork, the child process will have the P_PPWAIT
@@ -361,6 +681,7 @@ fbsd_wait (struct target_ops *ops,
 	      fbsd_fetch_kinfo_proc (child, &kp);
 	      if (kp.ki_flag & P_PPWAIT)
 		ourstatus->kind = TARGET_WAITKIND_VFORKED;
+	      ourstatus->value.related_pid = child_ptid;
 
 	      return wptid;
 	    }
@@ -370,7 +691,7 @@ fbsd_wait (struct target_ops *ops,
 	      /* Remember that this child forked, but do not report it
 		 until the parent reports its corresponding fork
 		 event.  */
-	      fbsd_remember_child (ptid_get_pid (wptid));
+	      fbsd_remember_child (wptid);
 	      continue;
 	    }
 #endif
@@ -449,13 +770,19 @@ fbsd_enable_follow_fork (pid_t pid)
   if (ptrace (PT_FOLLOW_FORK, pid, (PTRACE_TYPE_ARG3)0, 1) == -1)
     perror_with_name (("ptrace"));
 }
+#endif
 
 /* Implement the "to_post_startup_inferior" target_ops method.  */
 
 static void
 fbsd_post_startup_inferior (struct target_ops *self, ptid_t pid)
 {
+#ifdef TDP_RFPPWAIT
   fbsd_enable_follow_fork (ptid_get_pid (pid));
+#endif
+#ifdef PT_LWP_EVENTS
+  fbsd_enable_lwp_events (ptid_get_pid (pid));
+#endif
 }
 
 /* Implement the "to_post_attach" target_ops method.  */
@@ -463,9 +790,14 @@ fbsd_post_startup_inferior (struct target_ops *self, ptid_t pid)
 static void
 fbsd_post_attach (struct target_ops *self, int pid)
 {
+#ifdef TDP_RFPPWAIT
   fbsd_enable_follow_fork (pid);
-}
 #endif
+#ifdef PT_LWP_EVENTS
+  fbsd_enable_lwp_events (pid);
+#endif
+  fbsd_add_threads (pid);
+}
 
 #ifdef PL_FLAG_EXEC
 /* If the FreeBSD kernel supports PL_FLAG_EXEC, then traced processes
@@ -491,16 +823,25 @@ fbsd_nat_add_target (struct target_ops *t)
   t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
   t->to_find_memory_regions = fbsd_find_memory_regions;
 #ifdef PT_LWPINFO
+  t->to_thread_alive = fbsd_thread_alive;
+  t->to_pid_to_str = fbsd_pid_to_str;
+#ifdef HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME
+  t->to_thread_name = fbsd_thread_name;
+#endif
+  t->to_update_thread_list = fbsd_update_thread_list;
+  t->to_has_thread_control = tc_schedlock;
+  super_resume = t->to_resume;
+  t->to_resume = fbsd_resume;
   super_wait = t->to_wait;
   t->to_wait = fbsd_wait;
+  t->to_post_startup_inferior = fbsd_post_startup_inferior;
+  t->to_post_attach = fbsd_post_attach;
 #ifdef TDP_RFPPWAIT
   t->to_follow_fork = fbsd_follow_fork;
   t->to_insert_fork_catchpoint = fbsd_insert_fork_catchpoint;
   t->to_remove_fork_catchpoint = fbsd_remove_fork_catchpoint;
   t->to_insert_vfork_catchpoint = fbsd_insert_vfork_catchpoint;
   t->to_remove_vfork_catchpoint = fbsd_remove_vfork_catchpoint;
-  t->to_post_startup_inferior = fbsd_post_startup_inferior;
-  t->to_post_attach = fbsd_post_attach;
 #endif
 #ifdef PL_FLAG_EXEC
   t->to_insert_exec_catchpoint = fbsd_insert_exec_catchpoint;
@@ -509,3 +850,21 @@ fbsd_nat_add_target (struct target_ops *t)
 #endif
   add_target (t);
 }
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+extern initialize_file_ftype _initialize_fbsd_nat;
+
+void
+_initialize_fbsd_nat (void)
+{
+#ifdef PT_LWPINFO
+  add_setshow_boolean_cmd ("fbsd-lwp", class_maintenance,
+			   &debug_fbsd_lwp, _("\
+Set debugging of FreeBSD lwp module."), _("\
+Show debugging of FreeBSD lwp module."), _("\
+Enables printf debugging output."),
+			   NULL,
+			   &show_fbsd_lwp_debug,
+			   &setdebuglist, &showdebuglist);
+#endif
+}
-- 
2.7.0

[PATCH v4 2/7] Add a psuedosection for the NT_FREEBSD_THRMISC note.

[John Baldwin]

bfd/ChangeLog:

	* elf.c (elfcore_grok_note): Recognize NT_FREEBSD_THRMISC notes.
---
 bfd/ChangeLog | 4 ++++
 bfd/elf.c     | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index b6a7c5f..d157d3e 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,7 @@
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
+	* elf.c (elfcore_grok_note): Recognize NT_FREEBSD_THRMISC notes.
+
 2016-01-12  Yury Usishchev  <y.usishchev@samsung.com>
 
 	* elf32-arm.c (elf32_arm_fix_exidx_coverage): Insert cantunwind
diff --git a/bfd/elf.c b/bfd/elf.c
index a1f857a..b2a50bf 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -9287,6 +9287,13 @@ elfcore_grok_note (bfd *abfd, Elf_Internal_Note *note)
     case NT_SIGINFO:
       return elfcore_make_note_pseudosection (abfd, ".note.linuxcore.siginfo",
 					      note);
+
+    case NT_FREEBSD_THRMISC:
+      if (note->namesz == 8
+	  && strcmp (note->namedata, "FreeBSD") == 0)
+	return elfcore_make_note_pseudosection (abfd, ".thrmisc", note);
+      else
+	return TRUE;
     }
 }
 
-- 
2.7.0

[PATCH v4 0/7] Support kernel-backed user threads on FreeBSD

[John Baldwin]

This set of patches adds support for examining kernel-backed user threads on
FreeBSD.  There is more history in a comment in fbsd-nat.c, but this target
uses ptrace directly (instead of libthread_db) to support the current
threading library (libthr) on FreeBSD which uses a kernel thread for each
user thread.  Support for thread names in both core dumps (via FreeBSD's
OS-specific NT_THRMISC core note) and live is supported as is scheduler
locking.  gcore generates register notes for each thread as well.

The first two patches are to binutils to support FreeBSD-specific core
notes.  The last four are to GDB.

I've dropped binutils@ since the binutils patches have already been
ok'd and they haven't changed.

Relative to the previous version, this adds a new 'core_thread_name'
gdbarch method and moves the logic to fetch thread names for cores out of
fbsd_core_pid_to_str to a new fbsd_core_thread_name function.

John Baldwin (7):
  Add support to readelf for reading FreeBSD ELF core notes.
  Add a psuedosection for the NT_FREEBSD_THRMISC note.
  Add support for extracting thread names from cores.
  Display per-thread information for threads in FreeBSD cores.
  Use LWP IDs with ptrace register requests on FreeBSD.
  Add support for LWP-based threads on FreeBSD.
  Dump register notes for each thread when generating a FreeBSD core.

 bfd/ChangeLog        |   4 +
 bfd/elf.c            |   7 +
 binutils/ChangeLog   |   5 +
 binutils/readelf.c   |  35 +++++
 gdb/ChangeLog        |  82 ++++++++++
 gdb/NEWS             |   6 +
 gdb/amd64bsd-nat.c   |  24 +--
 gdb/config.in        |   3 +
 gdb/configure        |  16 ++
 gdb/configure.ac     |   7 +
 gdb/corelow.c        |  10 ++
 gdb/doc/ChangeLog    |   4 +
 gdb/doc/gdb.texinfo  |   5 +
 gdb/fbsd-nat.c       | 423 +++++++++++++++++++++++++++++++++++++++++++++++----
 gdb/fbsd-tdep.c      | 210 +++++++++++++++++++++----
 gdb/gdbarch.c        |  32 ++++
 gdb/gdbarch.h        |   9 ++
 gdb/gdbarch.sh       |   4 +
 gdb/i386bsd-nat.c    |  30 ++--
 gdb/inf-ptrace.c     |   2 +-
 gdb/inf-ptrace.h     |   5 +
 gdb/ppcfbsd-nat.c    |  12 +-
 include/ChangeLog    |  13 ++
 include/elf/common.h |  14 ++
 24 files changed, 870 insertions(+), 92 deletions(-)

-- 
2.7.0

[PATCH v4 1/7] Add support to readelf for reading FreeBSD ELF core notes.

[John Baldwin]

binutils/ChangeLog:

	* readelf.c (get_freebsd_elfcore_note_type): New
	(process_note): Add support for FreeBSD core notes.

include/ChangeLog:

	* elf/common.h (NT_FREEBSD_THRMISC): Define.
	(NT_FREEBSD_PROCSTAT_PROC): Define.
	(NT_FREEBSD_PROCSTAT_FILES): Define.
	(NT_FREEBSD_PROCSTAT_VMMAP): Define.
	(NT_FREEBSD_PROCSTAT_GROUPS): Define.
	(NT_FREEBSD_PROCSTAT_UMASK): Define.
	(NT_FREEBSD_PROCSTAT_RLIMIT): Define.
	(NT_FREEBSD_PROCSTAT_OSREL): Define.
	(NT_FREEBSD_PROCSTAT_PSSTRINGS): Define.
	(NT_FREEBSD_PROCSTAT_AUXV): Define.
---
 binutils/ChangeLog   |  5 +++++
 binutils/readelf.c   | 35 +++++++++++++++++++++++++++++++++++
 include/ChangeLog    | 13 +++++++++++++
 include/elf/common.h | 14 ++++++++++++++
 4 files changed, 67 insertions(+)

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 21dcb2c..47773c9 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,8 @@
+2016-01-09  John Baldwin  <jhb@FreeBSD.org>
+
+	* readelf.c (get_freebsd_elfcore_note_type): New
+	(process_note): Add support for FreeBSD core notes.
+
 2016-01-01  Alan Modra  <amodra@gmail.com>
 
 	Update year range in copyright notice of all files.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 47ac1ad..fa9cda1 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -15388,6 +15388,37 @@ process_netbsd_elf_note (Elf_Internal_Note * pnote)
 }
 
 static const char *
+get_freebsd_elfcore_note_type (unsigned e_type)
+{
+  static char buff[64];
+
+  switch (e_type)
+    {
+    case NT_FREEBSD_THRMISC:
+      return _("NT_THRMISC (thrmisc structure)");
+    case NT_FREEBSD_PROCSTAT_PROC:
+      return _("NT_PROCSTAT_PROC (proc data)");
+    case NT_FREEBSD_PROCSTAT_FILES:
+      return _("NT_PROCSTAT_FILES (files data)");
+    case NT_FREEBSD_PROCSTAT_VMMAP:
+      return _("NT_PROCSTAT_VMMAP (vmmap data)");
+    case NT_FREEBSD_PROCSTAT_GROUPS:
+      return _("NT_PROCSTAT_GROUPS (groups data)");
+    case NT_FREEBSD_PROCSTAT_UMASK:
+      return _("NT_PROCSTAT_UMASK (umask data)");
+    case NT_FREEBSD_PROCSTAT_RLIMIT:
+      return _("NT_PROCSTAT_RLIMIT (rlimit data)");
+    case NT_FREEBSD_PROCSTAT_OSREL:
+      return _("NT_PROCSTAT_OSREL (osreldate data)");
+    case NT_FREEBSD_PROCSTAT_PSSTRINGS:
+      return _("NT_PROCSTAT_PSSTRINGS (ps_strings data)");
+    case NT_FREEBSD_PROCSTAT_AUXV:
+      return _("NT_PROCSTAT_AUXV (auxv data)");
+    }
+  return get_note_type (e_type);
+}
+
+static const char *
 get_netbsd_elfcore_note_type (unsigned e_type)
 {
   static char buff[64];
@@ -15636,6 +15667,10 @@ process_note (Elf_Internal_Note * pnote)
     /* GNU-specific object file notes.  */
     nt = get_gnu_elf_note_type (pnote->type);
 
+  else if (const_strneq (pnote->namedata, "FreeBSD"))
+    /* FreeBSD-specific core file notes.  */
+    nt = get_freebsd_elfcore_note_type (pnote->type);
+
   else if (const_strneq (pnote->namedata, "NetBSD-CORE"))
     /* NetBSD-specific core file notes.  */
     nt = get_netbsd_elfcore_note_type (pnote->type);
diff --git a/include/ChangeLog b/include/ChangeLog
index 80fc4a8..7dadeba 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,16 @@
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
+	* elf/common.h (NT_FREEBSD_THRMISC): Define.
+	(NT_FREEBSD_PROCSTAT_PROC): Define.
+	(NT_FREEBSD_PROCSTAT_FILES): Define.
+	(NT_FREEBSD_PROCSTAT_VMMAP): Define.
+	(NT_FREEBSD_PROCSTAT_GROUPS): Define.
+	(NT_FREEBSD_PROCSTAT_UMASK): Define.
+	(NT_FREEBSD_PROCSTAT_RLIMIT): Define.
+	(NT_FREEBSD_PROCSTAT_OSREL): Define.
+	(NT_FREEBSD_PROCSTAT_PSSTRINGS): Define.
+	(NT_FREEBSD_PROCSTAT_AUXV): Define.
+
 2016-01-11  Nick Clifton  <nickc@redhat.com>
 
 	Import this change from GCC mainline:
diff --git a/include/elf/common.h b/include/elf/common.h
index ce506fc..767ad3e 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -595,6 +595,20 @@
 /* Note segment for SystemTap probes.  */
 #define NT_STAPSDT	3
 
+/* Note segments for core files on FreeBSD systems.  Note name is
+   "FreeBSD".  */
+
+#define	NT_FREEBSD_THRMISC	7	/* Thread miscellaneous info. */
+#define	NT_FREEBSD_PROCSTAT_PROC	8	/* Procstat proc data. */
+#define	NT_FREEBSD_PROCSTAT_FILES	9	/* Procstat files data. */
+#define	NT_FREEBSD_PROCSTAT_VMMAP	10	/* Procstat vmmap data. */
+#define	NT_FREEBSD_PROCSTAT_GROUPS	11	/* Procstat groups data. */
+#define	NT_FREEBSD_PROCSTAT_UMASK	12	/* Procstat umask data. */
+#define	NT_FREEBSD_PROCSTAT_RLIMIT	13	/* Procstat rlimit data. */
+#define	NT_FREEBSD_PROCSTAT_OSREL	14	/* Procstat osreldate data. */
+#define	NT_FREEBSD_PROCSTAT_PSSTRINGS	15	/* Procstat ps_strings data. */
+#define	NT_FREEBSD_PROCSTAT_AUXV	16	/* Procstat auxv data. */
+
 /* Note segments for core files on NetBSD systems.  Note name
    must start with "NetBSD-CORE".  */
 
-- 
2.7.0

[PATCH v4 7/7] Dump register notes for each thread when generating a FreeBSD core.

[John Baldwin]

gdb/ChangeLog:

	* fbsd-tdep.c (find_stop_signal): Remove.
	(struct fbsd_collect_regset_section_cb) <lwp>: New field.
	<stop_signal>: New field.
	<abort_iteration>: New field.
	(fbsd_collect_regset_section_cb): Use new fields.
	(fbsd_collect_thread_registers): New function.
	(struct fbsd_corefile_thread_data): New structure.
	(fbsd_corefile_thread): New function.
	(fbsd_make_corefile_notes): Use new function to dump notes for each
	non-exited thread in a process.
---
 gdb/ChangeLog   |  13 +++++
 gdb/fbsd-tdep.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++----------
 2 files changed, 131 insertions(+), 26 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ad81391..7eaa5b4 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,18 @@
 2016-01-16  John Baldwin  <jhb@FreeBSD.org>
 
+	* fbsd-tdep.c (find_stop_signal): Remove.
+	(struct fbsd_collect_regset_section_cb) <lwp>: New field.
+	<stop_signal>: New field.
+	<abort_iteration>: New field.
+	(fbsd_collect_regset_section_cb): Use new fields.
+	(fbsd_collect_thread_registers): New function.
+	(struct fbsd_corefile_thread_data): New structure.
+	(fbsd_corefile_thread): New function.
+	(fbsd_make_corefile_notes): Use new function to dump notes for each
+	non-exited thread in a process.
+
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
 	* configure.ac: Check for support for LWP names on FreeBSD.
 	* fbsd-nat.c [PT_LWPINFO] New variable debug_fbsd_lwp.
 	[TDP_RFPPWAIT || HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME]
diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
index b4e7eff..fa414e5 100644
--- a/gdb/fbsd-tdep.c
+++ b/gdb/fbsd-tdep.c
@@ -102,17 +102,9 @@ find_signalled_thread (struct thread_info *info, void *data)
   return 0;
 }
 
-static enum gdb_signal
-find_stop_signal (void)
-{
-  struct thread_info *info =
-    iterate_over_threads (find_signalled_thread, NULL);
-
-  if (info)
-    return info->suspend.stop_signal;
-  else
-    return GDB_SIGNAL_0;
-}
+/* Structure for passing information from
+   fbsd_collect_thread_registers via an iterator to
+   fbsd_collect_regset_section_cb. */
 
 struct fbsd_collect_regset_section_cb_data
 {
@@ -120,6 +112,9 @@ struct fbsd_collect_regset_section_cb_data
   bfd *obfd;
   char *note_data;
   int *note_size;
+  unsigned long lwp;
+  enum gdb_signal stop_signal;
+  int abort_iteration;
 };
 
 static void
@@ -131,6 +126,9 @@ fbsd_collect_regset_section_cb (const char *sect_name, int size,
   struct fbsd_collect_regset_section_cb_data *data
     = (struct fbsd_collect_regset_section_cb_data *) cb_data;
 
+  if (data->abort_iteration)
+    return;
+
   gdb_assert (regset->collect_regset);
 
   buf = (char *) xmalloc (size);
@@ -139,13 +137,73 @@ fbsd_collect_regset_section_cb (const char *sect_name, int size,
   /* PRSTATUS still needs to be treated specially.  */
   if (strcmp (sect_name, ".reg") == 0)
     data->note_data = (char *) elfcore_write_prstatus
-      (data->obfd, data->note_data, data->note_size,
-       ptid_get_pid (inferior_ptid), find_stop_signal (), buf);
+      (data->obfd, data->note_data, data->note_size, data->lwp,
+       gdb_signal_to_host (data->stop_signal), buf);
   else
     data->note_data = (char *) elfcore_write_register_note
       (data->obfd, data->note_data, data->note_size,
        sect_name, buf, size);
   xfree (buf);
+
+  if (data->note_data == NULL)
+    data->abort_iteration = 1;
+}
+
+/* Records the thread's register state for the corefile note
+   section.  */
+
+static char *
+fbsd_collect_thread_registers (const struct regcache *regcache,
+			       ptid_t ptid, bfd *obfd,
+			       char *note_data, int *note_size,
+			       enum gdb_signal stop_signal)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct fbsd_collect_regset_section_cb_data data;
+
+  data.regcache = regcache;
+  data.obfd = obfd;
+  data.note_data = note_data;
+  data.note_size = note_size;
+  data.stop_signal = stop_signal;
+  data.abort_iteration = 0;
+  data.lwp = ptid_get_lwp (ptid);
+
+  gdbarch_iterate_over_regset_sections (gdbarch,
+					fbsd_collect_regset_section_cb,
+					&data, regcache);
+  return data.note_data;
+}
+
+struct fbsd_corefile_thread_data
+{
+  struct gdbarch *gdbarch;
+  bfd *obfd;
+  char *note_data;
+  int *note_size;
+  enum gdb_signal stop_signal;
+};
+
+/* Records the thread's register state for the corefile note
+   section.  */
+
+static void
+fbsd_corefile_thread (struct thread_info *info,
+		      struct fbsd_corefile_thread_data *args)
+{
+  struct cleanup *old_chain;
+  struct regcache *regcache;
+
+  regcache = get_thread_arch_regcache (info->ptid, args->gdbarch);
+
+  old_chain = save_inferior_ptid ();
+  inferior_ptid = info->ptid;
+  target_fetch_registers (regcache, -1);
+  do_cleanups (old_chain);
+
+  args->note_data = fbsd_collect_thread_registers
+    (regcache, info->ptid, args->obfd, args->note_data,
+     args->note_size, args->stop_signal);
 }
 
 /* Create appropriate note sections for a corefile, returning them in
@@ -154,10 +212,10 @@ fbsd_collect_regset_section_cb (const char *sect_name, int size,
 static char *
 fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 {
-  struct regcache *regcache = get_current_regcache ();
-  char *note_data;
+  struct fbsd_corefile_thread_data thread_args;
+  char *note_data = NULL;
   Elf_Internal_Ehdr *i_ehdrp;
-  struct fbsd_collect_regset_section_cb_data data;
+  struct thread_info *curr_thr, *signalled_thr, *thr;
 
   /* Put a "FreeBSD" label in the ELF header.  */
   i_ehdrp = elf_elfheader (obfd);
@@ -165,16 +223,6 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 
   gdb_assert (gdbarch_iterate_over_regset_sections_p (gdbarch));
 
-  data.regcache = regcache;
-  data.obfd = obfd;
-  data.note_data = NULL;
-  data.note_size = note_size;
-  target_fetch_registers (regcache, -1);
-  gdbarch_iterate_over_regset_sections (gdbarch,
-					fbsd_collect_regset_section_cb,
-					&data, regcache);
-  note_data = data.note_data;
-
   if (get_exec_file (0))
     {
       const char *fname = lbasename (get_exec_file (0));
@@ -188,6 +236,50 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 					  fname, psargs);
     }
 
+  /* Thread register information.  */
+  TRY
+    {
+      update_thread_list ();
+    }
+  CATCH (e, RETURN_MASK_ERROR)
+    {
+      exception_print (gdb_stderr, e);
+    }
+  END_CATCH
+
+  /* Like the kernel, prefer dumping the signalled thread first.
+     "First thread" is what tools use to infer the signalled thread.
+     In case there's more than one signalled thread, prefer the
+     current thread, if it is signalled.  */
+  curr_thr = inferior_thread ();
+  if (curr_thr->suspend.stop_signal != GDB_SIGNAL_0)
+    signalled_thr = curr_thr;
+  else
+    {
+      signalled_thr = iterate_over_threads (find_signalled_thread, NULL);
+      if (signalled_thr == NULL)
+	signalled_thr = curr_thr;
+    }
+
+  thread_args.gdbarch = gdbarch;
+  thread_args.obfd = obfd;
+  thread_args.note_data = note_data;
+  thread_args.note_size = note_size;
+  thread_args.stop_signal = signalled_thr->suspend.stop_signal;
+
+  fbsd_corefile_thread (signalled_thr, &thread_args);
+  ALL_NON_EXITED_THREADS (thr)
+    {
+      if (thr == signalled_thr)
+	continue;
+      if (ptid_get_pid (thr->ptid) != ptid_get_pid (inferior_ptid))
+	continue;
+
+      fbsd_corefile_thread (thr, &thread_args);
+    }
+
+  note_data = thread_args.note_data;
+
   return note_data;
 }
 
-- 
2.7.0

[PATCH v4 3/7] Add support for extracting thread names from cores.

[John Baldwin]

Add a new gdbarch method to extract a thread name from a core for a
given thread.  Use this new method in core_thread_name to implement the
to_thread_name target op.

gdb/ChangeLog:

	* corelow.c (core_thread_name): New function.
	(init_core_ops): Use "core_thread_name" for the "to_thread_name"
	target op.
	* gdbarch.sh (core_thread_name): New gdbarch callback.
	* gdbarch.h: Re-generate.
	* gdbarch.c: Re-generate.
---
 gdb/ChangeLog  |  9 +++++++++
 gdb/corelow.c  | 10 ++++++++++
 gdb/gdbarch.c  | 32 ++++++++++++++++++++++++++++++++
 gdb/gdbarch.h  |  9 +++++++++
 gdb/gdbarch.sh |  4 ++++
 5 files changed, 64 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index fe8fd6c..bbac503 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
+	* corelow.c (core_thread_name): New function.
+	(init_core_ops): Use "core_thread_name" for the "to_thread_name"
+	target op.
+	* gdbarch.sh (core_thread_name): New gdbarch callback.
+	* gdbarch.h: Re-generate.
+	* gdbarch.c: Re-generate.
+
 2016-01-15  Sandra Loosemore  <sandra@codesourcery.com>
 
 	* charset.c [PHONY_ICONV] (GDB_DEFAULT_HOST_CHARSET):
diff --git a/gdb/corelow.c b/gdb/corelow.c
index 90e3d56..224719e 100644
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -986,6 +986,15 @@ core_pid_to_str (struct target_ops *ops, ptid_t ptid)
   return buf;
 }
 
+static const char *
+core_thread_name (struct target_ops *self, struct thread_info *thr)
+{
+  if (core_gdbarch
+      && gdbarch_core_thread_name_p (core_gdbarch))
+    return gdbarch_core_thread_name (core_gdbarch, thr);
+  return NULL;
+}
+
 static int
 core_has_memory (struct target_ops *ops)
 {
@@ -1038,6 +1047,7 @@ init_core_ops (void)
   core_ops.to_thread_alive = core_thread_alive;
   core_ops.to_read_description = core_read_description;
   core_ops.to_pid_to_str = core_pid_to_str;
+  core_ops.to_thread_name = core_thread_name;
   core_ops.to_stratum = process_stratum;
   core_ops.to_has_memory = core_has_memory;
   core_ops.to_has_stack = core_has_stack;
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index d45af1a..4143744 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -269,6 +269,7 @@ struct gdbarch
   gdbarch_core_xfer_shared_libraries_ftype *core_xfer_shared_libraries;
   gdbarch_core_xfer_shared_libraries_aix_ftype *core_xfer_shared_libraries_aix;
   gdbarch_core_pid_to_str_ftype *core_pid_to_str;
+  gdbarch_core_thread_name_ftype *core_thread_name;
   const char * gcore_bfd_target;
   int vtable_function_descriptors;
   int vbit_in_delta;
@@ -612,6 +613,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
   /* Skip verify of core_xfer_shared_libraries, has predicate.  */
   /* Skip verify of core_xfer_shared_libraries_aix, has predicate.  */
   /* Skip verify of core_pid_to_str, has predicate.  */
+  /* Skip verify of core_thread_name, has predicate.  */
   /* Skip verify of gcore_bfd_target, has predicate.  */
   /* Skip verify of vtable_function_descriptors, invalid_p == 0 */
   /* Skip verify of vbit_in_delta, invalid_p == 0 */
@@ -824,6 +826,12 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
                       "gdbarch_dump: core_read_description = <%s>\n",
                       host_address_to_string (gdbarch->core_read_description));
   fprintf_unfiltered (file,
+                      "gdbarch_dump: gdbarch_core_thread_name_p() = %d\n",
+                      gdbarch_core_thread_name_p (gdbarch));
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: core_thread_name = <%s>\n",
+                      host_address_to_string (gdbarch->core_thread_name));
+  fprintf_unfiltered (file,
                       "gdbarch_dump: gdbarch_core_xfer_shared_libraries_p() = %d\n",
                       gdbarch_core_xfer_shared_libraries_p (gdbarch));
   fprintf_unfiltered (file,
@@ -3554,6 +3562,30 @@ set_gdbarch_core_pid_to_str (struct gdbarch *gdbarch,
 }
 
 int
+gdbarch_core_thread_name_p (struct gdbarch *gdbarch)
+{
+  gdb_assert (gdbarch != NULL);
+  return gdbarch->core_thread_name != NULL;
+}
+
+const char *
+gdbarch_core_thread_name (struct gdbarch *gdbarch, struct thread_info *thr)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->core_thread_name != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_core_thread_name called\n");
+  return gdbarch->core_thread_name (gdbarch, thr);
+}
+
+void
+set_gdbarch_core_thread_name (struct gdbarch *gdbarch,
+                              gdbarch_core_thread_name_ftype core_thread_name)
+{
+  gdbarch->core_thread_name = core_thread_name;
+}
+
+int
 gdbarch_gcore_bfd_target_p (struct gdbarch *gdbarch)
 {
   gdb_assert (gdbarch != NULL);
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 3c16af2..3fadcd1 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -63,6 +63,7 @@ struct ravenscar_arch_ops;
 struct elf_internal_linux_prpsinfo;
 struct mem_range;
 struct syscalls_info;
+struct thread_info;
 
 #include "regcache.h"
 
@@ -866,6 +867,14 @@ typedef char * (gdbarch_core_pid_to_str_ftype) (struct gdbarch *gdbarch, ptid_t
 extern char * gdbarch_core_pid_to_str (struct gdbarch *gdbarch, ptid_t ptid);
 extern void set_gdbarch_core_pid_to_str (struct gdbarch *gdbarch, gdbarch_core_pid_to_str_ftype *core_pid_to_str);
 
+/* How the core target extracts the name of a thread from a core file. */
+
+extern int gdbarch_core_thread_name_p (struct gdbarch *gdbarch);
+
+typedef const char * (gdbarch_core_thread_name_ftype) (struct gdbarch *gdbarch, struct thread_info *thr);
+extern const char * gdbarch_core_thread_name (struct gdbarch *gdbarch, struct thread_info *thr);
+extern void set_gdbarch_core_thread_name (struct gdbarch *gdbarch, gdbarch_core_thread_name_ftype *core_thread_name);
+
 /* BFD target to use when generating a core file. */
 
 extern int gdbarch_gcore_bfd_target_p (struct gdbarch *gdbarch);
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index f80cd51..4ac6b90 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -721,6 +721,9 @@ M:ULONGEST:core_xfer_shared_libraries_aix:gdb_byte *readbuf, ULONGEST offset, UL
 # How the core target converts a PTID from a core file to a string.
 M:char *:core_pid_to_str:ptid_t ptid:ptid
 
+# How the core target extracts the name of a thread from a core file.
+M:const char *:core_thread_name:struct thread_info *thr:thr
+
 # BFD target to use when generating a core file.
 V:const char *:gcore_bfd_target:::0:0:::pstring (gdbarch->gcore_bfd_target)
 
@@ -1247,6 +1250,7 @@ struct ravenscar_arch_ops;
 struct elf_internal_linux_prpsinfo;
 struct mem_range;
 struct syscalls_info;
+struct thread_info;
 
 #include "regcache.h"
 
-- 
2.7.0

[PATCH v4 5/7] Use LWP IDs with ptrace register requests on FreeBSD.

[John Baldwin]

This allows gdb to fetch per-thread registers for multi-threaded FreeBSD
processes.

Export get_ptrace_pid() from inf-ptrace.c and use it to determine the PID
to pass to ptrace in pan-BSD native targets.  NetBSD and OpenBSD also accept
LWP IDs for ptrace requests to fetch per-thread state.

gdb/ChangeLog:

	* amd64bsd-nat.c (amd64bsd_fetch_inferior_registers): Use
	get_ptrace_pid.
	(amd64bsd_store_inferior_registers): Use get_ptrace_pid.
	(amd64bsd_dr_get): Use get_ptrace_pid.
	(amd64bsd_dr_set): Use get_ptrace_pid.
	* i386bsd-nat.c (i386bsd_fetch_inferior_registers): Use get_ptrace_pid.
	(i386bsd_store_inferior_registers): Use get_ptrace_pid.
	(i386bsd_dr_get): Use get_ptrace_pid.
	(i386bsd_dr_set): Use get_ptrace_pid.
	* inf-ptrace.c (get_ptrace_pid): Export.
	* inf-ptrace.h (get_ptrace_pid): Declare.
	* ppcfbsd-nat.c (ppcfbsd_fetch_inferior_registers): Use lwp id.
	(ppcfbsd_store_inferior_registers): Use lwp id.
---
 gdb/ChangeLog      | 16 ++++++++++++++++
 gdb/amd64bsd-nat.c | 24 ++++++++++++------------
 gdb/i386bsd-nat.c  | 30 +++++++++++++++---------------
 gdb/inf-ptrace.c   |  2 +-
 gdb/inf-ptrace.h   |  5 +++++
 gdb/ppcfbsd-nat.c  | 12 ++++++------
 6 files changed, 55 insertions(+), 34 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8f0fd34..5361932 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,21 @@
 2016-01-16  John Baldwin  <jhb@FreeBSD.org>
 
+	* amd64bsd-nat.c (amd64bsd_fetch_inferior_registers): Use
+	get_ptrace_pid.
+	(amd64bsd_store_inferior_registers): Use get_ptrace_pid.
+	(amd64bsd_dr_get): Use get_ptrace_pid.
+	(amd64bsd_dr_set): Use get_ptrace_pid.
+	* i386bsd-nat.c (i386bsd_fetch_inferior_registers): Use get_ptrace_pid.
+	(i386bsd_store_inferior_registers): Use get_ptrace_pid.
+	(i386bsd_dr_get): Use get_ptrace_pid.
+	(i386bsd_dr_set): Use get_ptrace_pid.
+	* inf-ptrace.c (get_ptrace_pid): Export.
+	* inf-ptrace.h (get_ptrace_pid): Declare.
+	* ppcfbsd-nat.c (ppcfbsd_fetch_inferior_registers): Use lwp id.
+	(ppcfbsd_store_inferior_registers): Use lwp id.
+
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
 	* fbsd_tdep.c (fbsd_core_pid_to_str): New function.
 	(fbsd_core_thread_name): New function.
 	(fbsd_init_abi): Add "core_pid_to_str" gdbarch method.
diff --git a/gdb/amd64bsd-nat.c b/gdb/amd64bsd-nat.c
index aa79c13..fb7e4fa 100644
--- a/gdb/amd64bsd-nat.c
+++ b/gdb/amd64bsd-nat.c
@@ -52,7 +52,7 @@ amd64bsd_fetch_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 	perror_with_name (_("Couldn't get registers"));
 
@@ -70,7 +70,7 @@ amd64bsd_fetch_inferior_registers (struct target_ops *ops,
       if (amd64bsd_xsave_len != 0)
 	{
 	  xstateregs = alloca (amd64bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
@@ -79,7 +79,7 @@ amd64bsd_fetch_inferior_registers (struct target_ops *ops,
 	}
 #endif
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get floating point status"));
 
@@ -100,13 +100,13 @@ amd64bsd_store_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't get registers"));
 
       amd64_collect_native_gregset (regcache, &regs, regnum);
 
-      if (ptrace (PT_SETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETREGS, get_ptrace_pid (inferior_ptid),
 	          (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't write registers"));
 
@@ -123,26 +123,26 @@ amd64bsd_store_inferior_registers (struct target_ops *ops,
       if (amd64bsd_xsave_len != 0)
 	{
 	  xstateregs = alloca (amd64bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
 	  amd64_collect_xsave (regcache, regnum, xstateregs, 0);
 
-	  if (ptrace (PT_SETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_SETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, amd64bsd_xsave_len) == -1)
 	    perror_with_name (_("Couldn't write extended state status"));
 	  return;
 	}
 #endif
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get floating point status"));
 
       amd64_collect_fxsave (regcache, regnum, &fpregs);
 
-      if (ptrace (PT_SETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETFPREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't write floating point status"));
     }
@@ -172,7 +172,7 @@ amd64bsd_dr_get (ptid_t ptid, int regnum)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't read debug registers"));
 
@@ -184,7 +184,7 @@ amd64bsd_dr_set (int regnum, unsigned long value)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't get debug registers"));
 
@@ -195,7 +195,7 @@ amd64bsd_dr_set (int regnum, unsigned long value)
 
   DBREG_DRX ((&dbregs), regnum) = value;
 
-  if (ptrace (PT_SETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_SETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't write debug registers"));
 }
diff --git a/gdb/i386bsd-nat.c b/gdb/i386bsd-nat.c
index 71f962c..5d45c33 100644
--- a/gdb/i386bsd-nat.c
+++ b/gdb/i386bsd-nat.c
@@ -138,7 +138,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 	perror_with_name (_("Couldn't get registers"));
 
@@ -160,7 +160,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
 	  char *xstateregs;
 
 	  xstateregs = alloca (i386bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
@@ -171,7 +171,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
       
 #ifdef HAVE_PT_GETXMMREGS
       if (have_ptrace_xmmregs != 0
-	  && ptrace(PT_GETXMMREGS, ptid_get_pid (inferior_ptid),
+	  && ptrace(PT_GETXMMREGS, get_ptrace_pid (inferior_ptid),
 		    (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 	{
 	  have_ptrace_xmmregs = 1;
@@ -181,7 +181,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
 	{
 	  have_ptrace_xmmregs = 0;
 #endif
-          if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+          if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't get floating point status"));
 
@@ -203,13 +203,13 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't get registers"));
 
       i386bsd_collect_gregset (regcache, &regs, regnum);
 
-      if (ptrace (PT_SETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETREGS, get_ptrace_pid (inferior_ptid),
 	          (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't write registers"));
 
@@ -230,13 +230,13 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
 	  char *xstateregs;
 
 	  xstateregs = alloca (i386bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
 	  i387_collect_xsave (regcache, -1, xstateregs, 0);
 
-	  if (ptrace (PT_SETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_SETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, i386bsd_xsave_len) == -1)
 	    perror_with_name (_("Couldn't write extended state status"));
 	  return;
@@ -245,14 +245,14 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
 
 #ifdef HAVE_PT_GETXMMREGS
       if (have_ptrace_xmmregs != 0
-	  && ptrace(PT_GETXMMREGS, ptid_get_pid (inferior_ptid),
+	  && ptrace(PT_GETXMMREGS, get_ptrace_pid (inferior_ptid),
 		    (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 	{
 	  have_ptrace_xmmregs = 1;
 
 	  i387_collect_fxsave (regcache, regnum, xmmregs);
 
-	  if (ptrace (PT_SETXMMREGS, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_SETXMMREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
             perror_with_name (_("Couldn't write XMM registers"));
 	}
@@ -260,13 +260,13 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
 	{
 	  have_ptrace_xmmregs = 0;
 #endif
-          if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+          if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't get floating point status"));
 
           i387_collect_fsave (regcache, regnum, &fpregs);
 
-          if (ptrace (PT_SETFPREGS, ptid_get_pid (inferior_ptid),
+          if (ptrace (PT_SETFPREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't write floating point status"));
 #ifdef HAVE_PT_GETXMMREGS
@@ -305,7 +305,7 @@ i386bsd_dr_get (ptid_t ptid, int regnum)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't read debug registers"));
 
@@ -317,7 +317,7 @@ i386bsd_dr_set (int regnum, unsigned int value)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't get debug registers"));
 
@@ -328,7 +328,7 @@ i386bsd_dr_set (int regnum, unsigned int value)
 
   DBREG_DRX ((&dbregs), regnum) = value;
 
-  if (ptrace (PT_SETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_SETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't write debug registers"));
 }
diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
index 8f8f4ee..329d8fb 100644
--- a/gdb/inf-ptrace.c
+++ b/gdb/inf-ptrace.c
@@ -304,7 +304,7 @@ inf_ptrace_interrupt (struct target_ops *self, ptid_t ptid)
 /* Return which PID to pass to ptrace in order to observe/control the
    tracee identified by PTID.  */
 
-static pid_t
+pid_t
 get_ptrace_pid (ptid_t ptid)
 {
   pid_t pid;
diff --git a/gdb/inf-ptrace.h b/gdb/inf-ptrace.h
index ec40590..0a26720 100644
--- a/gdb/inf-ptrace.h
+++ b/gdb/inf-ptrace.h
@@ -33,4 +33,9 @@ extern struct target_ops *
   inf_ptrace_trad_target (CORE_ADDR (*register_u_offset)
 					(struct gdbarch *, int, int));
 
+/* Return which PID to pass to ptrace in order to observe/control the
+   tracee identified by PTID.  */
+
+extern pid_t get_ptrace_pid (ptid_t);
+
 #endif
diff --git a/gdb/ppcfbsd-nat.c b/gdb/ppcfbsd-nat.c
index b41ed70..999e383 100644
--- a/gdb/ppcfbsd-nat.c
+++ b/gdb/ppcfbsd-nat.c
@@ -121,7 +121,7 @@ ppcfbsd_fetch_inferior_registers (struct target_ops *ops,
 {
   gdb_gregset_t regs;
 
-  if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETREGS, ptid_get_lwp (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
     perror_with_name (_("Couldn't get registers"));
 
@@ -132,7 +132,7 @@ ppcfbsd_fetch_inferior_registers (struct target_ops *ops,
       const struct regset *fpregset = ppc_fbsd_fpregset ();
       gdb_fpregset_t fpregs;
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, ptid_get_lwp (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get FP registers"));
 
@@ -149,13 +149,13 @@ ppcfbsd_store_inferior_registers (struct target_ops *ops,
 {
   gdb_gregset_t regs;
 
-  if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETREGS, ptid_get_lwp (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
     perror_with_name (_("Couldn't get registers"));
 
   fill_gregset (regcache, &regs, regno);
 
-  if (ptrace (PT_SETREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_SETREGS, ptid_get_lwp (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
     perror_with_name (_("Couldn't write registers"));
 
@@ -163,13 +163,13 @@ ppcfbsd_store_inferior_registers (struct target_ops *ops,
     {
       gdb_fpregset_t fpregs;
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, ptid_get_lwp (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get FP registers"));
 
       fill_fpregset (regcache, &fpregs, regno);
 
-      if (ptrace (PT_SETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETFPREGS, ptid_get_lwp (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't set FP registers"));
     }
-- 
2.7.0

[PATCH v4 4/7] Display per-thread information for threads in FreeBSD cores.

[John Baldwin]

Display the LWP ID of each thread in a FreeBSD core.  Extract thread
names from the per-thread THRMISC note.

gdb/ChangeLog:

	* fbsd_tdep.c (fbsd_core_pid_to_str): New function.
	(fbsd_core_thread_name): New function.
	(fbsd_init_abi): Add "core_pid_to_str" gdbarch method.
	Add "core_thread_name" gdbarch method.
---
 gdb/ChangeLog   |  7 ++++++
 gdb/fbsd-tdep.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index bbac503..8f0fd34 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
 2016-01-16  John Baldwin  <jhb@FreeBSD.org>
 
+	* fbsd_tdep.c (fbsd_core_pid_to_str): New function.
+	(fbsd_core_thread_name): New function.
+	(fbsd_init_abi): Add "core_pid_to_str" gdbarch method.
+	Add "core_thread_name" gdbarch method.
+
+2016-01-16  John Baldwin  <jhb@FreeBSD.org>
+
 	* corelow.c (core_thread_name): New function.
 	(init_core_ops): Use "core_thread_name" for the "to_thread_name"
 	target op.
diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
index 0ef94d6..b4e7eff 100644
--- a/gdb/fbsd-tdep.c
+++ b/gdb/fbsd-tdep.c
@@ -28,6 +28,70 @@
 #include "fbsd-tdep.h"
 
 
+/* This is how we want PTIDs from core files to be printed.  */
+
+static char *
+fbsd_core_pid_to_str (struct gdbarch *gdbarch, ptid_t ptid)
+{
+  static char buf[80];
+
+  if (ptid_get_lwp (ptid) != 0)
+    {
+      xsnprintf (buf, sizeof buf, "LWP %ld", ptid_get_lwp (ptid));
+      return buf;
+    }
+
+  return normal_pid_to_str (ptid);
+}
+
+/* Extract the name assigned to a thread from a core.  Returns the
+   string in a static buffer.  */
+
+static const char *
+fbsd_core_thread_name (struct gdbarch *gdbarch, struct thread_info *thr)
+{
+  static char buf[80];
+  struct bfd_section *section;
+  bfd_size_type size;
+  char sectionstr[32];
+
+  if (ptid_get_lwp (thr->ptid) != 0)
+    {
+      /* FreeBSD includes a NT_FREEBSD_THRMISC note for each thread
+	 whose contents are defined by a "struct thrmisc" declared in
+	 <sys/procfs.h> on FreeBSD.  The per-thread name is stored as
+	 a null-terminated string as the first member of the
+	 structure.  Rather than define the full structure here, just
+	 extract the null-terminated name from the start of the
+	 note.  */
+      xsnprintf (sectionstr, sizeof sectionstr, ".thrmisc/%ld",
+		ptid_get_lwp (thr->ptid));
+      section = bfd_get_section_by_name (core_bfd, sectionstr);
+      if (section != NULL && bfd_section_size (core_bfd, section) > 0)
+	{
+	  /* Truncate the name if it is longer than "buf".  */
+	  size = bfd_section_size (core_bfd, section);
+	  if (size > sizeof buf - 1)
+	    size = sizeof buf - 1;
+	  if (bfd_get_section_contents (core_bfd, section, buf, (file_ptr) 0,
+					size)
+	      && buf[0] != '\0')
+	    {
+	      buf[size] = '\0';
+
+	      /* Note that each thread will report the process command
+		 as its thread name instead of an empty name if a name
+		 has not been set explicitly.  Return a NULL name in
+		 that case.  */
+	      if (strcmp (buf, elf_tdata (core_bfd)->core->program) != 0)
+		  return buf;
+	    }
+	}
+    }
+
+  return NULL;
+}
+
 static int
 find_signalled_thread (struct thread_info *info, void *data)
 {
@@ -132,5 +196,7 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 void
 fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
+  set_gdbarch_core_pid_to_str (gdbarch, fbsd_core_pid_to_str);
+  set_gdbarch_core_thread_name (gdbarch, fbsd_core_thread_name);
   set_gdbarch_make_corefile_notes (gdbarch, fbsd_make_corefile_notes);
 }
-- 
2.7.0

Re: [PATCH v4 4/7] Display per-thread information for threads in FreeBSD cores.

[Pedro Alves]

This is OK.

On 01/18/2016 06:37 PM, John Baldwin wrote:

> +	      /* Note that each thread will report the process command
> +		 as its thread name instead of an empty name if a name
> +		 has not been set explicitly.  Return a NULL name in
> +		 that case.  */
> +	      if (strcmp (buf, elf_tdata (core_bfd)->core->program) != 0)
> +		  return buf;

(Not sure, but I think the alignment of that return is odd.)

Thanks,
Pedro Alves

Re: [PATCH v4 5/7] Use LWP IDs with ptrace register requests on FreeBSD.

[Pedro Alves]

OK.

Thanks,
Pedro Alves

Re: [PATCH v4 7/7] Dump register notes for each thread when generating a FreeBSD core.

[Pedro Alves]

OK.

Thanks,
Pedro Alves

Re: [PATCH v4 6/7] Add support for LWP-based threads on FreeBSD.

[Pedro Alves]

OK.

Thanks,
Pedro Alves

Re: [PATCH v4 2/7] Add a psuedosection for the NT_FREEBSD_THRMISC note.

[Pedro Alves]

Typo in $subject.  :-)

Thanks,
Pedro Alves

Re: [PATCH v4 3/7] Add support for extracting thread names from cores.

[Pedro Alves]

On 01/18/2016 06:37 PM, John Baldwin wrote:
> Add a new gdbarch method to extract a thread name from a core for a
> given thread.  Use this new method in core_thread_name to implement the
> to_thread_name target op.
> 
> gdb/ChangeLog:
> 
> 	* corelow.c (core_thread_name): New function.
> 	(init_core_ops): Use "core_thread_name" for the "to_thread_name"
> 	target op.
> 	* gdbarch.sh (core_thread_name): New gdbarch callback.
> 	* gdbarch.h: Re-generate.
> 	* gdbarch.c: Re-generate.

OK.  Thanks for doing this.

Thanks,
Pedro Alves

Re: [PATCH v4 2/7] Add a psuedosection for the NT_FREEBSD_THRMISC note.

[John Baldwin]

On Tuesday, January 19, 2016 10:39:00 AM Pedro Alves wrote:
> Typo in $subject.  :-)

Ugh, I edited the commit to specifically fix that.  Not sure how it was
still broken, but I've fixed it for real.

-- 
John Baldwin

Re: [PATCH v4 4/7] Display per-thread information for threads in FreeBSD cores.

[John Baldwin]

On Tuesday, January 19, 2016 10:39:19 AM Pedro Alves wrote:
> This is OK.
> 
> On 01/18/2016 06:37 PM, John Baldwin wrote:
> 
> > +	      /* Note that each thread will report the process command
> > +		 as its thread name instead of an empty name if a name
> > +		 has not been set explicitly.  Return a NULL name in
> > +		 that case.  */
> > +	      if (strcmp (buf, elf_tdata (core_bfd)->core->program) != 0)
> > +		  return buf;
> 
> (Not sure, but I think the alignment of that return is odd.)

Oops, it is, fixed.

-- 
John Baldwin