From patchwork Thu Apr 6 19:29:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matheus Tavares Bernardino X-Patchwork-Id: 13203943 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 95A06C76196 for ; Thu, 6 Apr 2023 19:30:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pkVJi-00089d-Qz; Thu, 06 Apr 2023 15:30:42 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pkVJh-00087h-3B for qemu-devel@nongnu.org; Thu, 06 Apr 2023 15:30:41 -0400 Received: from mx0a-0031df01.pphosted.com ([205.220.168.131]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pkVJc-0002HW-SZ for qemu-devel@nongnu.org; Thu, 06 Apr 2023 15:30:38 -0400 Received: from pps.filterd (m0279864.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 336IxolA026564; Thu, 6 Apr 2023 19:30:32 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=qcppdkim1; bh=h66j6eZ+I80USXh0GrYgRS1QgD8Txh3yUiMfM2aguDc=; b=k3NaIIZ9XnEJQ9mD5jqhq/sFGpdtKHFt/hfxOA8VezHSmniOhujCYVr4OqZOk5497Dml +fkfSROqONQpUK6cdL+3ROlrqE5mwBYUNS8vw7jP9u1GOrbSNZlkYTLSw1g7HYZO05f0 7z1T5iz7iP57gzEHPLb48XK3JKJPyFB6+OzlJr7eD5eFPEkxfXnI7im3mBmQZKNQYywb FLXqNu2HKm6hru4gyJLdM55LQ0fjGvgA34rjFv47WFQP+vyUe4ICOOXKJuikiabbOWll O+++OM8CM96fZlN754GZQWCHOpMJyLFkCkZK+VFv6cddJpYM5S9LosG3gaNkdmxK8J4G FA== Received: from nalasppmta04.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3psmyx2750-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 06 Apr 2023 19:30:32 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA04.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 336JUVcM018594 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 6 Apr 2023 19:30:31 GMT Received: from NASANPPMTA02.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.42; Thu, 6 Apr 2023 12:30:29 -0700 From: Matheus Tavares Bernardino To: CC: , , , , , =?utf-8?q?Philippe_Mathieu-D?= =?utf-8?q?aud=C3=A9?= Subject: [PATCH 1/7] gdbstub: only send stop-reply packets when allowed to Date: Thu, 6 Apr 2023 16:29:43 -0300 Message-ID: <48bce1b417f9701be26d737b596ccbd3dc2db573.1680808943.git.quic_mathbern@quicinc.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: References: MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: -axWKKILaxyytaEu9zX2d3ENeQVceC1d X-Proofpoint-ORIG-GUID: -axWKKILaxyytaEu9zX2d3ENeQVceC1d X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-04-06_11,2023-04-06_03,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 phishscore=0 impostorscore=0 adultscore=0 clxscore=1011 mlxlogscore=999 bulkscore=0 mlxscore=0 lowpriorityscore=0 spamscore=0 suspectscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303200000 definitions=main-2304060172 Received-SPF: pass client-ip=205.220.168.131; envelope-from=quic_mathbern@quicinc.com; helo=mx0a-0031df01.pphosted.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.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 --- gdbstub/internals.h | 5 +++++ gdbstub/gdbstub.c | 37 ++++++++++++++++++++++++++++--------- gdbstub/softmmu.c | 13 +++++++++++-- gdbstub/user.c | 17 +++++++++++------ 4 files changed, 55 insertions(+), 17 deletions(-) diff --git a/gdbstub/internals.h b/gdbstub/internals.h index 94ddff4495..33d21d6488 100644 --- a/gdbstub/internals.h +++ b/gdbstub/internals.h @@ -65,6 +65,11 @@ typedef struct GDBState { GByteArray *mem_buf; int sstep_flags; int supported_sstep_flags; + /* + * Whether we are allowed to send a stop reply packet at this moment. + * Must be set off after sending the stop reply itself. + */ + bool allow_stop_reply; } GDBState; /* lives in main gdbstub.c */ diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index 2a66371aa5..9d326a1d2d 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -777,6 +777,10 @@ typedef void (*GdbCmdHandler)(GArray *params, void *user_ctx); /* * cmd_startswith -> cmd is compared using startswith * + * allow_stop_reply -> true iff the gdbstub can respond to this command with a + * "stop reply" packet. The list of commands that accept such response is + * defined at the GDB Remote Serial Protocol documentation. see: + * https://sourceware.org/gdb/onlinedocs/gdb/Stop-Reply-Packets.html#Stop-Reply-Packets. * * schema definitions: * Each schema parameter entry consists of 2 chars, @@ -802,6 +806,7 @@ typedef struct GdbCmdParseEntry { const char *cmd; bool cmd_startswith; const char *schema; + bool allow_stop_reply; } GdbCmdParseEntry; static inline int startswith(const char *string, const char *pattern) @@ -835,6 +840,7 @@ static int process_string_cmd(void *user_ctx, const char *data, } } + gdbserver_state.allow_stop_reply = cmd->allow_stop_reply; cmd->handler(params, user_ctx); return 0; } @@ -1283,11 +1289,14 @@ static void handle_v_attach(GArray *params, void *user_ctx) gdbserver_state.g_cpu = cpu; gdbserver_state.c_cpu = cpu; - g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP); - gdb_append_thread_id(cpu, gdbserver_state.str_buf); - g_string_append_c(gdbserver_state.str_buf, ';'); + if (gdbserver_state.allow_stop_reply) { + g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP); + gdb_append_thread_id(cpu, gdbserver_state.str_buf); + g_string_append_c(gdbserver_state.str_buf, ';'); + gdbserver_state.allow_stop_reply = false; cleanup: - gdb_put_strbuf(); + gdb_put_strbuf(); + } } static void handle_v_kill(GArray *params, void *user_ctx) @@ -1310,12 +1319,14 @@ static const GdbCmdParseEntry gdb_v_commands_table[] = { .handler = handle_v_cont, .cmd = "Cont", .cmd_startswith = 1, + .allow_stop_reply = true, .schema = "s0" }, { .handler = handle_v_attach, .cmd = "Attach;", .cmd_startswith = 1, + .allow_stop_reply = true, .schema = "l0" }, { @@ -1698,10 +1709,13 @@ static void handle_gen_set(GArray *params, void *user_ctx) static void handle_target_halt(GArray *params, void *user_ctx) { - g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP); - gdb_append_thread_id(gdbserver_state.c_cpu, gdbserver_state.str_buf); - g_string_append_c(gdbserver_state.str_buf, ';'); - gdb_put_strbuf(); + if (gdbserver_state.allow_stop_reply) { + g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP); + gdb_append_thread_id(gdbserver_state.c_cpu, gdbserver_state.str_buf); + g_string_append_c(gdbserver_state.str_buf, ';'); + gdb_put_strbuf(); + gdbserver_state.allow_stop_reply = false; + } /* * Remove all the breakpoints when this query is issued, * because gdb is doing an initial connect and the state @@ -1725,7 +1739,8 @@ static int gdb_handle_packet(const char *line_buf) static const GdbCmdParseEntry target_halted_cmd_desc = { .handler = handle_target_halt, .cmd = "?", - .cmd_startswith = 1 + .cmd_startswith = 1, + .allow_stop_reply = true, }; cmd_parser = &target_halted_cmd_desc; } @@ -1736,6 +1751,7 @@ static int gdb_handle_packet(const char *line_buf) .handler = handle_continue, .cmd = "c", .cmd_startswith = 1, + .allow_stop_reply = true, .schema = "L0" }; cmd_parser = &continue_cmd_desc; @@ -1747,6 +1763,7 @@ static int gdb_handle_packet(const char *line_buf) .handler = handle_cont_with_sig, .cmd = "C", .cmd_startswith = 1, + .allow_stop_reply = true, .schema = "l0" }; cmd_parser = &cont_with_sig_cmd_desc; @@ -1785,6 +1802,7 @@ static int gdb_handle_packet(const char *line_buf) .handler = handle_step, .cmd = "s", .cmd_startswith = 1, + .allow_stop_reply = true, .schema = "L0" }; cmd_parser = &step_cmd_desc; @@ -1976,6 +1994,7 @@ void gdb_read_byte(uint8_t ch) { uint8_t reply; + gdbserver_state.allow_stop_reply = false; #ifndef CONFIG_USER_ONLY if (gdbserver_state.last_packet->len) { /* Waiting for a response to the last packet. If we see the start diff --git a/gdbstub/softmmu.c b/gdbstub/softmmu.c index 22ecd09d04..99d994e6bf 100644 --- a/gdbstub/softmmu.c +++ b/gdbstub/softmmu.c @@ -43,6 +43,7 @@ static void reset_gdbserver_state(void) g_free(gdbserver_state.processes); gdbserver_state.processes = NULL; gdbserver_state.process_num = 0; + gdbserver_state.allow_stop_reply = false; } /* @@ -139,6 +140,10 @@ static void gdb_vm_state_change(void *opaque, bool running, RunState state) return; } + if (!gdbserver_state.allow_stop_reply) { + return; + } + gdb_append_thread_id(cpu, tid); switch (state) { @@ -205,6 +210,7 @@ static void gdb_vm_state_change(void *opaque, bool running, RunState state) send_packet: gdb_put_packet(buf->str); + gdbserver_state.allow_stop_reply = false; /* disable single step if it was enabled */ cpu_single_step(cpu, 0); @@ -422,8 +428,11 @@ void gdb_exit(int code) trace_gdbstub_op_exiting((uint8_t)code); - snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code); - gdb_put_packet(buf); + if (gdbserver_state.allow_stop_reply) { + snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code); + gdb_put_packet(buf); + gdbserver_state.allow_stop_reply = false; + } qemu_chr_fe_deinit(&gdbserver_system_state.chr, true); } diff --git a/gdbstub/user.c b/gdbstub/user.c index 80488b6bb9..bb03622c83 100644 --- a/gdbstub/user.c +++ b/gdbstub/user.c @@ -127,11 +127,14 @@ int gdb_handlesig(CPUState *cpu, int sig) if (sig != 0) { gdb_set_stop_cpu(cpu); - g_string_printf(gdbserver_state.str_buf, - "T%02xthread:", gdb_target_signal_to_gdb(sig)); - gdb_append_thread_id(cpu, gdbserver_state.str_buf); - g_string_append_c(gdbserver_state.str_buf, ';'); - gdb_put_strbuf(); + if (gdbserver_state.allow_stop_reply) { + g_string_printf(gdbserver_state.str_buf, + "T%02xthread:", gdb_target_signal_to_gdb(sig)); + gdb_append_thread_id(cpu, gdbserver_state.str_buf); + g_string_append_c(gdbserver_state.str_buf, ';'); + gdb_put_strbuf(); + gdbserver_state.allow_stop_reply = false; + } } /* * gdb_put_packet() might have detected that the peer terminated the @@ -174,12 +177,14 @@ void gdb_signalled(CPUArchState *env, int sig) { char buf[4]; - if (!gdbserver_state.init || gdbserver_user_state.fd < 0) { + if (!gdbserver_state.init || gdbserver_user_state.fd < 0 || + !gdbserver_state.allow_stop_reply) { return; } snprintf(buf, sizeof(buf), "X%02x", gdb_target_signal_to_gdb(sig)); gdb_put_packet(buf); + gdbserver_state.allow_stop_reply = false; } static void gdb_accept_init(int fd)