[v2,07/12] btrace, gdbserver: Add ptwrite to btrace_config_pt.

Message ID 20210614145411.689277-3-felix.willgerodt@intel.com
State Superseded
Headers show
Series
  • Extensions for PTWRITE
Related show

Commit Message

Philippe Waroquiers via Gdb-patches June 14, 2021, 2:54 p.m.
This enables gdb and gdbserver to communicate about ptwrite support.  If
ptwrite support would be enabled unconditionally, GDBs with older libipt
versions would break.

gdb/ChangeLog:
2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

	* btrace.c (parse_xml_btrace_conf_pt): Add ptwrite to pt.conf.
	(btrace_conf_pt_attributes): Add ptwrite.

gdb/doc/ChangeLog:
2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

	* gdb.texinfo (General Query Packets): Document Qbtrace-conf:pt:ptwrite.
	(Branch Trace Configuration Format): Document ptwrite in btrace-conf.

gdbserver/ChangeLog:
2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

	* linux-low.cc (linux_process_target::read_btrace_conf): Add ptwrite.
	* server.cc (handle_btrace_conf_general_set): Handle pt:ptwrite.
	(supported_btrace_packets): Add Qbtrace-conf:pt:ptwrite.

gdbsupport/ChangeLog:
2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

	* btrace-common.h (btrace_config_pt): Add ptwrite.
---
 gdb/btrace.c                 |  7 ++++++-
 gdb/doc/gdb.texinfo          | 21 +++++++++++++++++++++
 gdb/features/btrace-conf.dtd |  1 +
 gdb/remote.c                 | 30 ++++++++++++++++++++++++++++++
 gdbserver/linux-low.cc       |  1 +
 gdbserver/server.cc          | 16 ++++++++++++++++
 gdbsupport/btrace-common.h   |  6 ++++++
 7 files changed, 81 insertions(+), 1 deletion(-)

-- 
2.25.4

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Comments

Philippe Waroquiers via Gdb-patches June 14, 2021, 3:53 p.m. | #1
> Date: Mon, 14 Jun 2021 16:54:06 +0200

> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>

> 

> This enables gdb and gdbserver to communicate about ptwrite support.  If

> ptwrite support would be enabled unconditionally, GDBs with older libipt

> versions would break.

> 

> gdb/ChangeLog:

> 2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

> 

> 	* btrace.c (parse_xml_btrace_conf_pt): Add ptwrite to pt.conf.

> 	(btrace_conf_pt_attributes): Add ptwrite.

> 

> gdb/doc/ChangeLog:

> 2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

> 

> 	* gdb.texinfo (General Query Packets): Document Qbtrace-conf:pt:ptwrite.

> 	(Branch Trace Configuration Format): Document ptwrite in btrace-conf.

> 

> gdbserver/ChangeLog:

> 2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

> 

> 	* linux-low.cc (linux_process_target::read_btrace_conf): Add ptwrite.

> 	* server.cc (handle_btrace_conf_general_set): Handle pt:ptwrite.

> 	(supported_btrace_packets): Add Qbtrace-conf:pt:ptwrite.

> 

> gdbsupport/ChangeLog:

> 2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

> 

> 	* btrace-common.h (btrace_config_pt): Add ptwrite.


The documentation part is OK, thanks.

Patch

diff --git a/gdb/btrace.c b/gdb/btrace.c
index 9f117a5e90d..2c4f3f67c6b 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -2261,7 +2261,7 @@  parse_xml_btrace_conf_pt (struct gdb_xml_parser *parser,
 			  std::vector<gdb_xml_value> &attributes)
 {
   struct btrace_config *conf;
-  struct gdb_xml_value *size;
+  struct gdb_xml_value *size, *ptwrite;
 
   conf = (struct btrace_config *) user_data;
   conf->format = BTRACE_FORMAT_PT;
@@ -2270,10 +2270,15 @@  parse_xml_btrace_conf_pt (struct gdb_xml_parser *parser,
   size = xml_find_attribute (attributes, "size");
   if (size != NULL)
     conf->pt.size = (unsigned int) *(ULONGEST *) size->value.get ();
+
+  ptwrite = xml_find_attribute (attributes, "ptwrite");
+  if (ptwrite != NULL)
+    conf->pt.ptwrite = (bool) *(ULONGEST *) ptwrite->value.get ();
 }
 
 static const struct gdb_xml_attribute btrace_conf_pt_attributes[] = {
   { "size", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+  { "ptwrite", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 };
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 5e4f8e73b7d..60c1340d31d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -41906,6 +41906,11 @@  These are the currently defined stub features and their properties:
 @tab @samp{-}
 @tab Yes
 
+@item @samp{Qbtrace-conf:pt:ptwrite}
+@tab Yes
+@tab @samp{-}
+@tab Yes
+
 @item @samp{QNonStop}
 @tab No
 @tab @samp{-}
@@ -42217,6 +42222,9 @@  The remote stub understands the @samp{Qbtrace-conf:bts:size} packet.
 @item Qbtrace-conf:pt:size
 The remote stub understands the @samp{Qbtrace-conf:pt:size} packet.
 
+@item Qbtrace-conf:pt:ptwrite
+The remote stub understands the @samp{Qbtrace-conf:pt:ptwrite} packet.
+
 @item swbreak
 The remote stub reports the @samp{swbreak} stop reason for memory
 breakpoints.
@@ -42717,6 +42725,18 @@  The ring buffer size has been set.
 A badly formed request or an error was encountered.
 @end table
 
+@item Qbtrace-conf:pt:ptwrite=@var{value}
+Control recording of ptwrite packets.  This was added for backwards-
+compatibility.
+
+Reply:
+@table @samp
+@item OK
+The ptwrite config parameter has been set.
+@item E.errtext
+A badly formed request or an error was encountered.
+@end table
+
 @end table
 
 @node Architecture-Specific Protocol Details
@@ -45359,6 +45379,7 @@  The formal DTD for the branch trace configuration format is given below:
 
 <!ELEMENT pt	EMPTY>
 <!ATTLIST pt	size	CDATA	#IMPLIED>
+<!ATTLIST pt	ptwrite	CDATA	#IMPLIED>
 @end smallexample
 
 @include agentexpr.texi
diff --git a/gdb/features/btrace-conf.dtd b/gdb/features/btrace-conf.dtd
index 4b060bb408c..339ce4a4966 100644
--- a/gdb/features/btrace-conf.dtd
+++ b/gdb/features/btrace-conf.dtd
@@ -12,3 +12,4 @@ 
 
 <!ELEMENT pt	EMPTY>
 <!ATTLIST pt	size	CDATA	#IMPLIED>
+<!ATTLIST pt	ptwrite	CDATA	#IMPLIED>
diff --git a/gdb/remote.c b/gdb/remote.c
index 22933eeaeec..554dbbf107b 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -2168,6 +2168,9 @@  enum {
   /* Support for the Qbtrace-conf:pt:size packet.  */
   PACKET_Qbtrace_conf_pt_size,
 
+  /* Support for the Qbtrace-conf:pt:ptwrite packet.  */
+  PACKET_Qbtrace_conf_pt_ptwrite,
+
   /* Support for exec events.  */
   PACKET_exec_event_feature,
 
@@ -5328,6 +5331,8 @@  static const struct protocol_feature remote_protocol_features[] = {
     PACKET_exec_event_feature },
   { "Qbtrace-conf:pt:size", PACKET_DISABLE, remote_supported_packet,
     PACKET_Qbtrace_conf_pt_size },
+  { "Qbtrace-conf:pt:ptwrite", PACKET_DISABLE, remote_supported_packet,
+    PACKET_Qbtrace_conf_pt_ptwrite },
   { "vContSupported", PACKET_DISABLE, remote_supported_packet, PACKET_vContSupported },
   { "QThreadEvents", PACKET_DISABLE, remote_supported_packet, PACKET_QThreadEvents },
   { "no-resumed", PACKET_DISABLE, remote_supported_packet, PACKET_no_resumed },
@@ -14028,6 +14033,28 @@  remote_target::btrace_sync_conf (const btrace_config *conf)
 
       rs->btrace_config.pt.size = conf->pt.size;
     }
+
+  packet = &remote_protocol_packets[PACKET_Qbtrace_conf_pt_ptwrite];
+  if (packet_config_support (packet) == PACKET_ENABLE
+      && conf->pt.ptwrite != rs->btrace_config.pt.ptwrite)
+    {
+      pos = buf;
+      pos += xsnprintf (pos, endbuf - pos, "%s=%d", packet->name,
+                        conf->pt.ptwrite);
+
+      putpkt (buf);
+      getpkt (&rs->buf, 0);
+
+      if (packet_ok (buf, packet) == PACKET_ERROR)
+	{
+	  if (buf[0] == 'E' && buf[1] == '.')
+	    error (_("Failed to sync ptwrite config: %s"), buf + 2);
+	  else
+	    error (_("Failed to sync ptwrite config."));
+	}
+
+      rs->btrace_config.pt.ptwrite = conf->pt.ptwrite;
+    }
 }
 
 /* Read the current thread's btrace configuration from the target and
@@ -15230,6 +15257,9 @@  Show the maximum size of the address (in bits) in a memory packet."), NULL,
   add_packet_config_cmd (&remote_protocol_packets[PACKET_Qbtrace_conf_pt_size],
        "Qbtrace-conf:pt:size", "btrace-conf-pt-size", 0);
 
+  add_packet_config_cmd (&remote_protocol_packets[PACKET_Qbtrace_conf_pt_ptwrite],
+       "Qbtrace-conf:pt:ptwrite", "btrace-conf-pt-ptwrite", 0);
+
   add_packet_config_cmd (&remote_protocol_packets[PACKET_vContSupported],
 			 "vContSupported", "verbose-resume-supported", 0);
 
diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
index 5c6191d941c..6554e9766ab 100644
--- a/gdbserver/linux-low.cc
+++ b/gdbserver/linux-low.cc
@@ -7096,6 +7096,7 @@  linux_process_target::read_btrace_conf (const btrace_target_info *tinfo,
 	case BTRACE_FORMAT_PT:
 	  buffer_xml_printf (buffer, "<pt");
 	  buffer_xml_printf (buffer, " size=\"0x%x\"", conf->pt.size);
+	  buffer_xml_printf (buffer, " ptwrite=\"%d\"", conf->pt.ptwrite);
 	  buffer_xml_printf (buffer, "/>\n");
 	  break;
 	}
diff --git a/gdbserver/server.cc b/gdbserver/server.cc
index 32dcc05924e..b899f50db35 100644
--- a/gdbserver/server.cc
+++ b/gdbserver/server.cc
@@ -546,6 +546,21 @@  handle_btrace_conf_general_set (char *own_buf)
 
       current_btrace_conf.pt.size = (unsigned int) size;
     }
+  else if (strncmp (op, "pt:ptwrite=", strlen ("pt:ptwrite=")) == 0)
+    {
+      int ptwrite;
+      char *endp = NULL;
+
+      errno = 0;
+      ptwrite = strtoul (op + strlen ("pt:ptwrite="), &endp, 16);
+      if (endp == NULL || *endp != 0 || errno != 0 || ptwrite > 1)
+	{
+	  strcpy (own_buf, "E.Bad ptwrite value.");
+	  return -1;
+	}
+
+      current_btrace_conf.pt.ptwrite = (bool) ptwrite;
+    }
   else
     {
       strcpy (own_buf, "E.Bad Qbtrace configuration option.");
@@ -2189,6 +2204,7 @@  supported_btrace_packets (char *buf)
   strcat (buf, ";Qbtrace-conf:bts:size+");
   strcat (buf, ";Qbtrace:pt+");
   strcat (buf, ";Qbtrace-conf:pt:size+");
+  strcat (buf, ";Qbtrace-conf:pt:ptwrite+");
   strcat (buf, ";Qbtrace:off+");
   strcat (buf, ";qXfer:btrace:read+");
   strcat (buf, ";qXfer:btrace-conf:read+");
diff --git a/gdbsupport/btrace-common.h b/gdbsupport/btrace-common.h
index 26d26ec957f..ccdf2fc25af 100644
--- a/gdbsupport/btrace-common.h
+++ b/gdbsupport/btrace-common.h
@@ -117,6 +117,12 @@  struct btrace_config_pt
      This is unsigned int and not size_t since it is registered as
      control variable for "set record btrace pt buffer-size".  */
   unsigned int size;
+
+  /* Configuration bit for ptwrite packets.
+
+     If this is set, gdb will try to enable ptwrite packets if the OS
+     supports this.  */
+  bool ptwrite;
 };
 
 /* A branch tracing configuration.