base/SOURCES/gdb-rhbz1261564-aarch64-hw-watchpoint-2of5.patch

http://sourceware.org/ml/gdb-patches/2015-02/msg00733.html
Subject: [PATCH 4/8] remote+docs: software/hardware breakpoint traps

This adjusts target remote to tell the core whether a trap was caused
by a breakpoint.

To that end, the patch teaches GDB about new RSP stop reasons "T05
swbreak" and "T05 hwbreak", that remote targets report back to GDB,
similarly to how "T05 watch" indicates a stop caused by a watchpoint.

Because targets that can report these events are expected to
themselves adjust the PC after a software breakpoint, these new stop
reasons must only be reported if the stub is talking to a GDB that
understands them.  Because of that, the use of the new stop reasons
needs to be handshaked on initial connection, using the qSupported
mechanism.  GDB simply sends "swbreak+" in its qSupports query, and
the stub reports back "swbreak+" too.

Because these new stop reasons are required to fix a fundamental
non-stop mode problem, this commit extends the remote non-stop intro
section in the manual, documenting the events as required.

To be clear, GDB will still cope with remote targets that don't
support these new stop reasons; it will behave just like today.

Tested on x86-64 Fedora 20, native and gdbserver.

gdb/ChangeLog:
2015-02-25  Pedro Alves  <palves@redhat.com>

	* NEWS: Mention the new "swbreak" and "hwbreak" stop reasons.
	* remote.c (struct remote_state) <remote_stopped_by_watchpoint_p>:
	Delete field.
	<stop_reason>: New field.
	(PACKET_swbreak_feature, PACKET_hwbreak_feature): New enum values.
	(packet_set_cmd_state): New function.
	(remote_protocol_features): Register the "swbreak" and "hwbreak"
	features.
	(remote_query_supported): If not disabled with the corresponding
	"set remote foo-packet" command, report support for the swbreak
	and hwbreak features.
	(struct stop_reply) <remote_stopped_by_watchpoint_p>: Delete
	field.
	<stop_reason>: New field.
	(remote_parse_stop_reply): Handle "swbreak" and "hwbreak".
	(remote_wait_as): Adjust.
	(remote_stopped_by_sw_breakpoint)
	(remote_supports_stopped_by_sw_breakpoint)
	(remote_stopped_by_hw_breakpoint)
	(remote_supports_stopped_by_hw_breakpoint): New functions.
	(remote_stopped_by_watchpoint): New function.
	(init_remote_ops): Install them.
	(_initialize_remote): Register new "set/show remote
	swbreak-feature-packet" and "set/show remote
	swbreak-feature-packet" commands.

gdb/doc/ChangeLog:
2015-02-25  Pedro Alves  <palves@redhat.com>

	* gdb.texinfo (Remote Configuration): Document the "set/show
	remote swbreak-feature-packet" and "set/show remote
	hwbreak-feature-packet" commands.
	(Packets) <Z0>: Add cross link to the "swbreak" stop reason's
	decription.
	(Stop Reply Packets): Document the swbreak and hwbreak stop
	reasons.
	(General Query Packets): Document the swbreak and hwbreak
	qSupported features.
	(Remote Non-Stop): Explain that swbreak and hwbreak are required.
---
 gdb/NEWS            |  10 +++++
 gdb/doc/gdb.texinfo |  80 +++++++++++++++++++++++++++++++++++
 gdb/remote.c        | 119 ++++++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 200 insertions(+), 9 deletions(-)

Index: gdb-7.6.1/gdb/remote.c
===================================================================
--- gdb-7.6.1.orig/gdb/remote.c	2016-03-13 19:41:32.258628611 +0100
+++ gdb-7.6.1/gdb/remote.c	2016-03-13 19:42:35.787094677 +0100
@@ -728,6 +728,9 @@
 /* This is non-zero if target stopped for a watchpoint.  */
 static int remote_stopped_by_watchpoint_p;
 
+/* RHEL: TARGET_STOPPED_BY_HW_BREAKPOINT */
+static int stopped_by_hw_breakpoint;
+
 static struct target_ops remote_ops;
 
 static struct target_ops extended_remote_ops;
@@ -1289,11 +1292,24 @@
   PACKET_Qbtrace_off,
   PACKET_Qbtrace_bts,
   PACKET_qXfer_btrace,
+
+  /* Support for hwbreak+ feature.  */
+  PACKET_hwbreak_feature,
+
   PACKET_MAX
 };
 
 static struct packet_config remote_protocol_packets[PACKET_MAX];
 
+/* Returns the packet's corresponding "set remote foo-packet" command
+   state.  See struct packet_config for more details.  */
+
+static enum auto_boolean
+packet_set_cmd_state (int packet)
+{
+  return remote_protocol_packets[packet].detect;
+}
+
 static void
 set_remote_protocol_packet_cmd (char *args, int from_tty,
 				struct cmd_list_element *c)
@@ -4017,7 +4033,8 @@
   { "Qbtrace:off", PACKET_DISABLE, remote_supported_packet, PACKET_Qbtrace_off },
   { "Qbtrace:bts", PACKET_DISABLE, remote_supported_packet, PACKET_Qbtrace_bts },
   { "qXfer:btrace:read", PACKET_DISABLE, remote_supported_packet,
-    PACKET_qXfer_btrace }
+    PACKET_qXfer_btrace },
+  { "hwbreak", PACKET_DISABLE, remote_supported_packet, PACKET_hwbreak_feature }
 };
 
 static char *remote_support_xml;
@@ -4086,6 +4103,9 @@
 
       q = remote_query_supported_append (q, "multiprocess+");
 
+      if (packet_set_cmd_state (PACKET_hwbreak_feature) != AUTO_BOOLEAN_FALSE)
+	q = remote_query_supported_append (q, "hwbreak+");
+
       if (remote_support_xml)
 	q = remote_query_supported_append (q, remote_support_xml);
 
@@ -5202,6 +5222,9 @@
   int stopped_by_watchpoint_p;
   CORE_ADDR watch_data_address;
 
+  /* RHEL: TARGET_STOPPED_BY_HW_BREAKPOINT */
+  int stopped_by_hw_breakpoint;
+
   int solibs_changed;
   int replay_event;
 
@@ -5467,6 +5490,7 @@
   event->solibs_changed = 0;
   event->replay_event = 0;
   event->stopped_by_watchpoint_p = 0;
+  event->stopped_by_hw_breakpoint = 0;
   event->regcache = NULL;
   event->core = -1;
 
@@ -5522,6 +5546,23 @@
 		  p = unpack_varlen_hex (++p1, &addr);
 		  event->watch_data_address = (CORE_ADDR) addr;
 		}
+	      else if (strncmp (p, "hwbreak", p1 - p) == 0)
+		{
+		  event->stopped_by_hw_breakpoint = 1;
+
+		  /* Make sure the stub doesn't forget to indicate support
+		     with qSupported.  */
+		  //if (packet_support (PACKET_hwbreak_feature) != PACKET_ENABLE)
+		  //  error (_("Unexpected hwbreak stop reason"));
+
+		  /* See above.  */
+		  //p = skip_to_semicolon (p1 + 1);
+		  p1++;
+		  p_temp = p1;
+		  while (*p_temp && *p_temp != ';')
+		    p_temp++;
+		  p = p_temp;
+		}
 	      else if (strncmp (p, "library", p1 - p) == 0)
 		{
 		  p1++;
@@ -5783,6 +5824,7 @@
 
       remote_stopped_by_watchpoint_p = stop_reply->stopped_by_watchpoint_p;
       remote_watch_data_address = stop_reply->watch_data_address;
+      stopped_by_hw_breakpoint = stop_reply->stopped_by_hw_breakpoint;
 
       remote_notice_new_inferior (ptid, 0);
       demand_private_info (ptid)->core = stop_reply->core;
@@ -8310,6 +8352,16 @@
   return -1;
 }
 
+/* The to_stopped_by_hw_breakpoint method of target remote.  */
+
+static int
+remote_stopped_by_hw_breakpoint (struct target_ops *ops)
+{
+  struct remote_state *rs = get_remote_state ();
+
+  return stopped_by_hw_breakpoint;
+}
+
 static int
 remote_stopped_by_watchpoint (void)
 {
@@ -11372,6 +11424,7 @@
   remote_ops.to_files_info = remote_files_info;
   remote_ops.to_insert_breakpoint = remote_insert_breakpoint;
   remote_ops.to_remove_breakpoint = remote_remove_breakpoint;
+  remote_ops.to_stopped_by_hw_breakpoint = remote_stopped_by_hw_breakpoint;
   remote_ops.to_stopped_by_watchpoint = remote_stopped_by_watchpoint;
   remote_ops.to_stopped_data_address = remote_stopped_data_address;
   remote_ops.to_watchpoint_addr_within_range =
@@ -12010,6 +12063,9 @@
   add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_btrace],
        "qXfer:btrace", "read-btrace", 0);
 
+  add_packet_config_cmd (&remote_protocol_packets[PACKET_hwbreak_feature],
+                         "hwbreak-feature", "hwbreak-feature", 0);
+
   /* Keep the old ``set remote Z-packet ...'' working.  Each individual
      Z sub-packet has its own set and show commands, but users may
      have sets to this variable in their .gdbinit files (or in their