History log of /freebsd-head/sys/gdb/gdb_int.h
Revision Date Author Comments
b6995dbc52725d5d20b1958d2bf4c31306451b63 17-Oct-2019 cem <cem@FreeBSD.org> gdb(4): Implement support for NoAckMode

When the underlying debugport transport is reliable, GDB's additional
checksums and acknowledgements are redundant. NoAckMode eliminates the
the acks and allows us to skip checking RX checksums. The GDB packet
framing does not change, so unfortunately (valid) checksums are still
included as message trailers.

The gdb(4) stub in FreeBSD advertises support for the feature in response to
the client's 'qSupported' request IFF the current debugport has the
gdb_dbfeatures flag GDB_DBGP_FEAT_RELIABLE set. Currently, only netgdb(4)
supports this feature.

If the remote GDB client supports the feature and does not have it disabled
via a GDB configuration knob, it may instruct our gdb(4) stub to enter
NoAckMode. Unless and until it issues that command, we must continue to
transmit acks as usual (and for now, we continue to wait until we receive
them as well, even if we know the debugport is on a reliable transport).

In the kernel sources, the sense of the flag representing the state of the
feature is reversed from that of the GDB command. (I.e., it is
'gdb_ackmode', not 'gdb_noackmode.') This is to avoid confusing double-
negative conditions.

For reference, see:
* https://sourceware.org/gdb/onlinedocs/gdb/Packet-Acknowledgment.html
* https://sourceware.org/gdb/onlinedocs/gdb/General-Query-Packets.html#QStartNoAckMode

Reviewed by: jhb, markj (both earlier version)
Differential Revision: https://reviews.freebsd.org/D21761
45bf92cd2073000d53c185c6b871f8ac9c9aaeec 17-Oct-2019 cem <cem@FreeBSD.org> Implement NetGDB(4)

NetGDB(4) is a component of a system using a panic-time network stack to
remotely debug crashed FreeBSD kernels over the network, instead of
traditional serial interfaces.

There are three pieces in the complete NetGDB system.

First, a dedicated proxy server must be running to accept connections from
both NetGDB and gdb(1), and pass bidirectional traffic between the two

Second, the NetGDB client is activated much like ordinary 'gdb' and
similarly to 'netdump' in ddb(4) after a panic. Like other debugnet(4)
clients (netdump(4)), the network interface on the route to the proxy server
must be online and support debugnet(4).

Finally, the remote (k)gdb(1) uses 'target remote <proxy>:<port>' (like any
other TCP remote) to connect to the proxy server.

The NetGDB v1 protocol speaks the literal GDB remote serial protocol, and
uses a 1:1 relationship between GDB packets and sequences of debugnet
packets (fragmented by MTU). There is no encryption utilized to keep
debugging sessions private, so this is only appropriate for local
segments or trusted networks.

Submitted by: John Reimer <john.reimer AT emc.com> (earlier version)
Discussed some with: emaste, markj
Relnotes: sure
Differential Revision: https://reviews.freebsd.org/D21568
1430355eaac6319c5618a630173868cbd850d168 08-Sep-2019 cem <cem@FreeBSD.org> gdb(4): Root a sysctl tree at 'debug.gdb.'

Like debug.ddb and debug.kdb. Rename 'debug.gdbcons' to 'debug.gdb.cons,'
but leave the old name as a compatibility alias.
2eac8765d1d35dc9af0f3768a50a36614b64762c 22-Aug-2019 cem <cem@FreeBSD.org> gdb(4): Style

No functional change.

I was surprised to find that no sys/ header already defines the -1 EOF
convention anywhere, so defined one locally.
ddc3aef3cd088aeb7c0740cd9db469cf68904dec 19-Aug-2019 cem <cem@FreeBSD.org> gdb(4): Pack 'info threads' responses into fewer packets

We suffer at least one round trip ACK latency every command / packet that
GDB has to send and receive, and the response format for 'info threads'
supports packing many threads IDs into a single packet, so do so.

Adds and uses a new API, gdb_txbuf_has_capacity(), which checks for a
certain number of bytes available in the outgoing txbuf.

On an example amd64 VM, the number of RTTs to transmit this list is reduced
by a factor of 110x. This is especially beneficial with recent GDB, which
seems to request the list at least twice during attach.
273d7fd5bbbdc1d47c696eaf4fc75779393a1c12 27-Nov-2017 pfg <pfg@FreeBSD.org> sys/gdb: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
00d578928eca75be320b36d37543a7e2a4f9fbdb 27-May-2016 grehan <grehan@FreeBSD.org> Create branch for bhyve graphics import.
b46fbbac90c150e0c7ed397aee01711a8e2b6461 05-Sep-2014 benno <benno@FreeBSD.org> Add support for gdb's memory searching capabilities to our in-kernel gdb

Submitted by: Daniel O'Connor <daniel.oconnor@isilon.com>
Reviewed by: jhb
Sponsored by: EMC Isilon Storage Division
eb1a5f8de9f7ea602c373a710f531abbf81141c4 21-Feb-2014 gjb <gjb@FreeBSD.org> Move ^/user/gjb/hacking/release-embedded up one directory, and remove
^/user/gjb/hacking since this is likely to be merged to head/ soon.

Sponsored by: The FreeBSD Foundation
6b01bbf146ab195243a8e7d43bb11f8835c76af8 27-Dec-2013 gjb <gjb@FreeBSD.org> Copy head@r259933 -> user/gjb/hacking/release-embedded for initial
inclusion of (at least) arm builds with the release.

Sponsored by: The FreeBSD Foundation
09f9c897d33c41618ada06fbbcf1a9b3812dee53 19-Oct-2010 jamie <jamie@FreeBSD.org> A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.
f1216d1f0ade038907195fc114b7e630623b402c 19-Mar-2010 delphij <delphij@FreeBSD.org> Create a custom branch where I will be able to do the merge.
19b6af98ec71398e77874582eb84ec5310c7156f 22-Nov-2008 dfr <dfr@FreeBSD.org> Clone Kip's Xen on stable/6 tree so that I can work on improving FreeBSD/amd64
performance in Xen's HVM mode.
cf5320822f93810742e3d4a1ac8202db8482e633 19-Oct-2008 lulf <lulf@FreeBSD.org> - Import the HEAD csup code which is the basis for the cvsmode work.
2b0d21fae435871bcb97cd52a823b403fb7a5a55 23-Mar-2006 sam <sam@FreeBSD.org> add support for copying console messages to a remote gdb

Reviewed by: kan
872b48591b4303f2f41cb64cf1c4be26b5348f2f 06-Jan-2005 imp <imp@FreeBSD.org> /* -> /*- for copyright notices, minor format tweaks as necessary
6e0dcca8a9676834e327681abedbeca81a0907f2 10-Jul-2004 marcel <marcel@FreeBSD.org> Introduce the GDB debugger backend for the new KDB framework. The
backend improves over the old GDB support in the following ways:
o Unified implementation with minimal MD code.
o A simple interface for devices to register themselves as debug
ports, ala consoles.
o Compression by using run-length encoding.
o Implements GDB threading support.