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2024-06-24gdbstub: move enums into separate headerAlex Bennée1-0/+1
This is an experiment to further reduce the amount we throw into the exec headers. It might not be as useful as I initially thought because just under half of the users also need gdbserver_start(). Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20240620152220.2192768-3-alex.bennee@linaro.org>
2024-03-13gdbstub: Fix double close() of the follow-fork-mode socketIlya Leoshkevich1-2/+1
When the terminal GDB_FORK_ENABLED state is reached, the coordination socket is not needed anymore and is therefore closed. However, if there is a communication error between QEMU gdbstub and GDB, the generic error handling code attempts to close it again. Fix by closing it later - before returning - instead. Fixes: Coverity CID 1539966 Fixes: d547e711a8a5 ("gdbstub: Implement follow-fork-mode child") Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240312001813.13720-1-iii@linux.ibm.com>
2024-03-13gdbstub: Add Xfer:siginfo:read stubGustavo Romero1-0/+23
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>
2024-03-13gdbstub: Save target's siginfoGustavo Romero1-4/+19
Save target's siginfo into gdbserver_state so it can be used later, for example, in any stub that requires the target's si_signo and si_code. This change affects only linux-user mode. Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org> Suggested-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20240309030901.1726211-4-gustavo.romero@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2024-03-13gdbstub: Rename back gdb_handlesigGustavo Romero1-4/+4
Rename gdb_handlesig_reason back to gdb_handlesig. There is no need to add a wrapper for gdb_handlesig and rename it when a new parameter is added. Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20240309030901.1726211-2-gustavo.romero@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
2024-03-06gdbstub: Implement follow-fork-mode childIlya Leoshkevich1-2/+210
Currently it's not possible to use gdbstub for debugging linux-user code that runs in a forked child, which is normally done using the `set follow-fork-mode child` GDB command. Purely on the protocol level, the missing piece is the fork-events feature. However, a deeper problem is supporting $Hg switching between different processes - right now it can do only threads. Implementing this for the general case would be quite complicated, but, fortunately, for the follow-fork-mode case there are a few factors that greatly simplify things: fork() happens in the exclusive section, there are only two processes involved, and before one of them is resumed, the second one is detached. This makes it possible to implement a simplified scheme: the parent and the child share the gdbserver socket, it's used only by one of them at any given time, which is coordinated through a separate socketpair. The processes can read from the gdbserver socket only one byte at a time, which is not great for performance, but, fortunately, the follow-fork-mode handling involves only a few messages. Advertise the fork-events support, and remember whether GDB has it as well. Implement the state machine that is initialized on fork(), decides the current owner of the gdbserver socket, and is terminated when one of the two processes is detached. The logic for the parent and the child is the same, only the initial state is different. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-12-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-13-alex.bennee@linaro.org>
2024-03-06gdbstub: Introduce gdb_handle_detach_user()Ilya Leoshkevich1-0/+5
The upcoming follow-fork-mode child support needs to perform certain actions when GDB detaches from the stopped parent or the stopped child. Introduce a user-specific hook for this. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-11-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-12-alex.bennee@linaro.org>
2024-03-06gdbstub: Introduce gdb_handle_set_thread_user()Ilya Leoshkevich1-0/+5
The upcoming follow-fork-mode child support needs to perform certain actions when GDB switches between the stopped parent and the stopped child. Introduce a user-specific hook for this. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-10-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-11-alex.bennee@linaro.org>
2024-03-06gdbstub: Introduce gdb_handle_query_supported_user()Ilya Leoshkevich1-0/+4
The upcoming follow-fork-mode child support requires advertising the fork-events feature, which is user-specific. Introduce a user-specific hook for this. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-9-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-10-alex.bennee@linaro.org>
2024-03-06gdbstub: Call gdbserver_fork() both in parent and in childIlya Leoshkevich1-3/+2
The upcoming follow-fork-mode child support requires post-fork message exchange between the parent and the child. Prepare gdbserver_fork() for this purpose. Rename it to gdbserver_fork_end() to better reflect its purpose. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-8-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-9-alex.bennee@linaro.org>
2024-03-06{linux,bsd}-user: Pass pid to gdbserver_fork()Ilya Leoshkevich1-1/+1
The upcoming follow-fork-mode child support requires knowing the child pid. Pass it down. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-7-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-8-alex.bennee@linaro.org>
2024-03-06gdbstub: Introduce gdbserver_fork_start()Ilya Leoshkevich1-0/+4
The upcoming follow-fork-mode child support requires knowing when fork() is about to happen in order to initialize its state. Add a hook for that. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-5-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-6-alex.bennee@linaro.org>
2024-03-06gdbstub: Support disablement in a multi-threaded processIlya Leoshkevich1-4/+15
The upcoming follow-fork-mode child support will require disabling gdbstub in the parent process, which may have multiple threads (which are represented as CPUs). Loop over all CPUs in order to remove breakpoints and disable single-step. Move the respective code into a separate function. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-2-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-3-alex.bennee@linaro.org>
2024-02-09gdbstub: Implement catching syscallsIlya Leoshkevich1-0/+91
GDB supports stopping on syscall entry and exit using the "catch syscall" command. It relies on 3 packets, which are currently not supported by QEMU: * qSupported:QCatchSyscalls+ [1] * QCatchSyscalls: [2] * T05syscall_entry: and T05syscall_return: [3] Implement generation and handling of these packets. [1] https://sourceware.org/gdb/current/onlinedocs/gdb.html/General-Query-Packets.html#qSupported [2] https://sourceware.org/gdb/current/onlinedocs/gdb.html/General-Query-Packets.html#QCatchSyscalls [3] https://sourceware.org/gdb/current/onlinedocs/gdb.html/Stop-Reply-Packets.html Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240202152506.279476-5-iii@linux.ibm.com> [AJB: GString -> g_strdup_printf] Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240207163812.3231697-14-alex.bennee@linaro.org>
2024-02-09gdbstub: Add syscall entry/return hooksIlya Leoshkevich1-0/+8
The upcoming syscall catchpoint support needs to get control on syscall entry and return. Provide the necessary hooks for that, which are no-ops for now. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240202152506.279476-4-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240207163812.3231697-13-alex.bennee@linaro.org>
2024-02-09gdbstub: Allow specifying a reason in stop packetsIlya Leoshkevich1-1/+4
The upcoming syscall catchpoint support needs to send stop packets with an associated reason to GDB. Add an extra parameter to gdb_handlesig() for that, and rename it to gdb_handlesig_reason(). Provide a compatibility wrapper with an old name. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240202152506.279476-3-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240207163812.3231697-12-alex.bennee@linaro.org>
2023-10-12gdbstub: replace exit calls with proper shutdown for softmmuClément Chigot1-0/+6
This replaces the exit calls by shutdown requests, ensuring a proper cleanup of Qemu. Features like net/vhost-vdpa.c are expecting qemu_cleanup to be called to remove their last residuals. Signed-off-by: Clément Chigot <chigot@adacore.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-ID: <20231003071427.188697-6-chigot@adacore.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2023-08-30gdbstub: replace global gdb_has_xml with a functionAlex Bennée1-1/+0
Try and make the self reported global hack a little less hackish by providing a query function instead. As gdb_has_xml was always set if we negotiated XML we can now use the presence of ->target_xml as the test instead. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230829161528.2707696-12-alex.bennee@linaro.org>
2023-05-18gdbstub: only send stop-reply packets when allowed toMatheus Tavares Bernardino1-8/+16
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>
2023-03-07gdbstub: split out softmmu/user specifics for syscall handlingAlex Bennée1-0/+14
Most of the syscall code is config agnostic aside from the size of target_ulong. In preparation for the next patch move the final bits of specialisation into the appropriate user and softmmu helpers. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20230302190846.2593720-26-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-26-richard.henderson@linaro.org>
2023-03-07gdbstub: move syscall handling to new fileAlex Bennée1-0/+1
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>
2023-03-07gdbstub: specialise stub_can_reverseAlex Bennée1-0/+5
Currently we only support replay for softmmu mode so it is a constant false for user-mode. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230302190846.2593720-18-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-18-richard.henderson@linaro.org>
2023-03-07gdbstub: introduce gdb_get_max_cpusAlex Bennée1-0/+17
This is needed for handling vcont packets as the way of calculating max cpus vhanges between user and softmmu mode. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230302190846.2593720-17-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-17-richard.henderson@linaro.org>
2023-03-07gdbstub: specialise target_memory_rw_debugAlex Bennée1-0/+15
The two implementations are different enough to encourage having a specialisation and we can move some of the softmmu only stuff out of gdbstub. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230302190846.2593720-16-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-16-richard.henderson@linaro.org>
2023-03-07gdbstub: specialise handle_query_attachedAlex Bennée1-0/+5
In both user and softmmu cases we are just replying with a constant. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230302190846.2593720-15-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-15-richard.henderson@linaro.org>
2023-03-07gdbstub: abstract target specific details from gdb_put_packet_binaryAlex Bennée1-0/+19
We unfortunately handle the checking of packet acknowledgement differently for user and softmmu modes. Abstract the user mode stuff behind gdb_got_immediate_ack with a stub for softmmu. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230302190846.2593720-14-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-14-richard.henderson@linaro.org>
2023-03-07gdbstub: move chunks of user code into own filesAlex Bennée1-0/+344
The process was pretty similar to the softmmu move except we take the time to split stuff between user.c and user-target.c to avoid as much target specific compilation as possible. We also start to make use of our shiny new header scheme so the user-only helpers can be included without the rest of the exec/gsbstub.h cruft. As before we split some functions into user and softmmu versions Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230302190846.2593720-12-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-12-richard.henderson@linaro.org>
2023-03-07gdbstub: fix-up copyright and license filesAlex Bennée1-1/+2
When I started splitting gdbstub apart I was a little too boilerplate with my file headers. Fix up to carry over Fabrice's copyright and the LGPL license header. Fixes: ae7467b1ac (gdbstub: move breakpoint logic to accel ops) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20230302190846.2593720-3-alex.bennee@linaro.org> Message-Id: <20230303025805.625589-3-richard.henderson@linaro.org>
2023-02-27gdbstub: Use vaddr type for generic insert/remove_breakpoint() APIPhilippe Mathieu-Daudé1-3/+2
Both insert/remove_breakpoint() handlers are used in system and user emulation. We can not use the 'hwaddr' type on user emulation, we have to use 'vaddr' which is defined as "wide enough to contain any #target_ulong virtual address". gdbstub.c doesn't require to include "exec/hwaddr.h" anymore. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Fabiano Rosas <farosas@suse.de> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20221216215519.5522-4-philmd@linaro.org>
2022-10-06gdbstub: move guest debug support check to opsAlex Bennée1-0/+6
This removes the final hard coding of kvm_enabled() in gdbstub and moves the check to an AccelOps. Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Mads Ynddal <mads@ynddal.dk> Message-Id: <20220929114231.583801-46-alex.bennee@linaro.org>
2022-10-06gdbstub: move breakpoint logic to accel opsAlex Bennée1-0/+62
As HW virtualization requires specific support to handle breakpoints lets push out special casing out of the core gdbstub code and into AccelOpsClass. This will make it easier to add other accelerator support and reduces some of the stub shenanigans. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Mads Ynddal <mads@ynddal.dk> Message-Id: <20220929114231.583801-45-alex.bennee@linaro.org>