Re: [PATCH] gdbstub: Switch to the thread receiving a signal

[Pavel Labath <pavel@labath.sk>]

Ping.

(This is my first qemu patch, so please let me know if I am doing 
something wrong.)

regards,
pavel

On 30/09/2021 11:51, Pavel Labath wrote:
> Respond with Txxthread:yyyy; instead of a plain Sxx to indicate which
> thread received the signal. Otherwise, the debugger will associate it
> with the main one. Also automatically select this thread, as that is
> what gdb expects.
> 
> Signed-off-by: Pavel Labath <pavel@labath.sk>
> ---
>   gdbstub.c                                     |  9 ++-
>   tests/tcg/multiarch/Makefile.target           |  7 +++
>   .../gdbstub/test-thread-breakpoint.py         | 60 +++++++++++++++++++
>   3 files changed, 74 insertions(+), 2 deletions(-)
>   create mode 100644 tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py
> 
> diff --git a/gdbstub.c b/gdbstub.c
> index 36b85aa..7bd4479 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -3138,8 +3138,13 @@ gdb_handlesig(CPUState *cpu, int sig)
>       tb_flush(cpu);
>   
>       if (sig != 0) {
> -        snprintf(buf, sizeof(buf), "S%02x", target_signal_to_gdb(sig));
> -        put_packet(buf);
> +        gdbserver_state.c_cpu = cpu;
> +        gdbserver_state.g_cpu = cpu;
> +        g_string_printf(gdbserver_state.str_buf,
> +                        "T%02xthread:", target_signal_to_gdb(sig));
> +        gdb_append_thread_id(cpu, gdbserver_state.str_buf);
> +        g_string_append_c(gdbserver_state.str_buf, ';');
> +        put_strbuf();
>       }
>       /* put_packet() might have detected that the peer terminated the
>          connection.  */
> diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target
> index 85a6fb7..c7b7e8b 100644
> --- a/tests/tcg/multiarch/Makefile.target
> +++ b/tests/tcg/multiarch/Makefile.target
> @@ -73,6 +73,13 @@ run-gdbstub-qxfer-auxv-read: sha1
>   		--bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \
>   	"basic gdbstub qXfer:auxv:read support")
>   
> +run-gdbstub-thread-breakpoint: testthread
> +	$(call run-test, $@, $(GDB_SCRIPT) \
> +		--gdb $(HAVE_GDB_BIN) \
> +		--qemu $(QEMU) --qargs "$(QEMU_OPTS)" \
> +		--bin $< --test $(MULTIARCH_SRC)/gdbstub/test-thread-breakpoint.py, \
> +	"hitting a breakpoint on non-main thread")
> +
>   else
>   run-gdbstub-%:
>   	$(call skip-test, "gdbstub test $*", "need working gdb")
> diff --git a/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py
> new file mode 100644
> index 0000000..798d508
> --- /dev/null
> +++ b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py
> @@ -0,0 +1,60 @@
> +from __future__ import print_function
> +#
> +# Test auxiliary vector is loaded via gdbstub
> +#
> +# This is launched via tests/guest-debug/run-test.py
> +#
> +
> +import gdb
> +import sys
> +
> +failcount = 0
> +
> +def report(cond, msg):
> +    "Report success/fail of test"
> +    if cond:
> +        print ("PASS: %s" % (msg))
> +    else:
> +        print ("FAIL: %s" % (msg))
> +        global failcount
> +        failcount += 1
> +
> +def run_test():
> +    "Run through the tests one by one"
> +
> +    sym, ok = gdb.lookup_symbol("thread1_func")
> +    gdb.execute("b thread1_func")
> +    gdb.execute("c")
> +
> +    frame = gdb.selected_frame()
> +    report(str(frame.function()) == "thread1_func", "break @ %s"%frame)
> +
> +#
> +# This runs as the script it sourced (via -x, via run-test.py)
> +#
> +try:
> +    inferior = gdb.selected_inferior()
> +    arch = inferior.architecture()
> +    print("ATTACHED: %s" % arch.name())
> +except (gdb.error, AttributeError):
> +    print("SKIPPING (not connected)", file=sys.stderr)
> +    exit(0)
> +
> +if gdb.parse_and_eval('$pc') == 0:
> +    print("SKIP: PC not set")
> +    exit(0)
> +
> +try:
> +    # These are not very useful in scripts
> +    gdb.execute("set pagination off")
> +    gdb.execute("set confirm off")
> +
> +    # Run the actual tests
> +    run_test()
> +except (gdb.error):
> +    print ("GDB Exception: %s" % (sys.exc_info()[0]))
> +    failcount += 1
> +    pass
> +
> +print("All tests complete: %d failures" % failcount)
> +exit(failcount)
>