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