Currently, it's not possible to have stubs specific to a given target,
even though there are GDB features which are target-specific, like, for
instance, memory tagging.
This commit introduces gdb_extend_qsupported_features,
gdb_extend_query_table, and gdb_extend_set_table functions as interfaces
to extend the qSupported string, the query handler table, and the set
handler table, allowing target-specific stub implementations.
Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240628050850.536447-4-gustavo.romero@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240705084047.857176-33-alex.bennee@linaro.org>
Move GdbCmdParseEntry and its associated types into a separate header
file to allow the use of GdbCmdParseEntry and other gdbstub command
functions outside of gdbstub.c.
Since GdbCmdParseEntry and get_param are now public, kdoc
GdbCmdParseEntry and rename get_param to gdb_get_cmd_param.
This commit also makes gdb_put_packet public since is used in gdbstub
command handling.
Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240628050850.536447-3-gustavo.romero@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240705084047.857176-32-alex.bennee@linaro.org>
Add stub to handle Xfer:siginfo:read packet query that requests the
machine's siginfo data.
This is used when GDB user executes 'print $_siginfo' and when the
machine stops due to a signal, for instance, on SIGSEGV. The information
in siginfo allows GDB to determiner further details on the signal, like
the fault address/insn when the SIGSEGV is caught.
Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Message-Id: <20240309030901.1726211-5-gustavo.romero@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Fixes: 761e3c1088 "gdbstub: fixes cases where wrong threads were reported to GDB on SIGINT"
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Try to bring up the code to more modern standards by:
- use dynamic GString built xml over a fixed buffer
- use autofree to save on explicit g_free() calls
- don't hand hack strstr to find the delimiter
- fix up style of xml_builtin and invert loop
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230829161528.2707696-11-alex.bennee@linaro.org>
When starting a remote connection GDB sends an '+':
/* Ack any packet which the remote side has already sent. */
remote_serial_write ("+", 1);
which gets flagged as a garbage character in the gdbstub state
machine. As gdb does send it out lets be permissive about the handling
so we can better see real issues.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: gdb-patches@sourceware.org
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230810153640.1879717-9-alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Previously, qemu-user would always report PID 1 to GDB. This was changed
at dc14a7a6e9 (gdbstub: Report the actual qemu-user pid, 2023-06-30),
but read_thread_id() still considers GDB packets with "no PID" as "PID
1", which is not the qemu-user PID. Fix that by parsing "no PID" as "0",
which the GDB Remote Protocol defines as "any process".
Note that this should have no effect for system emulation as, in this
case, gdb_create_default_process() will assign PID 1 for the first
process and that is what the gdbstub uses for GDB requests with no PID,
or PID 0.
This issue was found with hexagon-lldb, which sends a "Hg" packet with
only the thread-id, but no process-id, leading to the invalid usage of
"PID 1" by qemu-hexagon and a subsequent "E22" reply.
Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <78a3b06f6ab90a7ff8e73ae14a996eb27ec76c85.1690904195.git.quic_mathbern@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The gdb remote protocol has a special interrupt character (0x03) that is
transmitted outside the regular packet processing, and represents a
Ctrl-C pressed in the client. Despite not being a regular packet, it
does expect a regular stop response if the stub successfully stops the
running program.
See: https://sourceware.org/gdb/onlinedocs/gdb/Interrupts.html
Inhibiting the stop reply packet can lead to gdb client hang. So permit
a stop response when receiving a character from gdb that stops the vm.
Additionally, add a warning if that was not a 0x03 character, because
the gdb session is likely to end up getting confused if this happens.
Cc: qemu-stable@nongnu.org
Fixes: 758370052f ("gdbstub: only send stop-reply packets when allowed to")
Reported-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Message-id: 20230711085903.304496-1-npiggin@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Currently the GDB's generate-core-file command doesn't work well with
qemu-user: the resulting dumps are huge [1] and at the same time
incomplete (argv and envp are missing). The reason is that GDB has no
access to proc mappings and therefore has to fall back to using
heuristics for discovering them. This is, in turn, because qemu-user
does not implement the Host I/O feature of the GDB Remote Serial
Protocol.
Implement vFile:{open,close,pread,readlink} and also
qXfer:exec-file:read+. With that, generate-core-file begins to work on
aarch64 and s390x.
[1] https://sourceware.org/pipermail/gdb-patches/2023-May/199432.html
Co-developed-by: Dominik 'Disconnect3d' Czarnota <dominik.b.czarnota@gmail.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230621203627.1808446-7-iii@linux.ibm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230630180423.558337-37-alex.bennee@linaro.org>
GDB's remote serial protocol allows stop-reply messages to be sent by
the stub either as a notification packet or as a reply to a GDB command
(provided that the cmd accepts such a response). QEMU currently does not
implement notification packets, so it should only send stop-replies
synchronously and when requested. Nevertheless, it still issues
unsolicited stop messages through gdb_vm_state_change().
Although this behavior doesn't seem to cause problems with GDB itself
(the messages are just ignored), it can impact other debuggers that
implement the GDB remote serial protocol, like hexagon-lldb. Let's
change the gdbstub to send stop messages only as a response to a
previous GDB command that accepts such a reply.
Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <a49c0897fc22a6a7827c8dfc32aef2e1d933ec6b.1683214375.git.quic_mathbern@quicinc.com>
Our GDB syscall support is the last chunk of code that needs target
specific support so move it to a new file. We take the opportunity to
move the syscall state into its own singleton instance and add in a
few helpers for the main gdbstub to interact with the module.
I also moved the gdb_exit() declaration into syscalls.h as it feels
pretty related and most of the callers of it treat it as such.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230302190846.2593720-22-alex.bennee@linaro.org>
Message-Id: <20230303025805.625589-22-richard.henderson@linaro.org>
