From 761e3c10881b5f521b19b713cf8d16c72c47affb Mon Sep 17 00:00:00 2001 From: Matheus Branco Borella Date: Tue, 29 Aug 2023 17:15:24 +0100 Subject: gdbstub: fixes cases where wrong threads were reported to GDB on SIGINT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This fix is implemented by having the vCont handler set the value of `gdbserver_state.c_cpu` if any threads are to be resumed. The specific CPU picked is arbitrarily from the ones to be resumed, but it should be okay, as all GDB cares about is that it is a resumed thread. Signed-off-by: Matheus Branco Borella Message-Id: <20230804182633.47300-2-dark.ryu.550@gmail.com> [AJB: style and whitespace fixes] Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1725 Signed-off-by: Alex Bennée Message-Id: <20230829161528.2707696-9-alex.bennee@linaro.org> --- gdbstub/gdbstub.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'gdbstub/gdbstub.c') diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index 5f28d5cf57..e7d48fa0d4 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -597,6 +597,15 @@ static int gdb_handle_vcont(const char *p) * or incorrect parameters passed. */ res = 0; + + /* + * target_count and last_target keep track of how many CPUs we are going to + * step or resume, and a pointer to the state structure of one of them, + * respectivelly + */ + int target_count = 0; + CPUState *last_target = NULL; + while (*p) { if (*p++ != ';') { return -ENOTSUP; @@ -637,6 +646,9 @@ static int gdb_handle_vcont(const char *p) while (cpu) { if (newstates[cpu->cpu_index] == 1) { newstates[cpu->cpu_index] = cur_action; + + target_count++; + last_target = cpu; } cpu = gdb_next_attached_cpu(cpu); @@ -654,6 +666,9 @@ static int gdb_handle_vcont(const char *p) while (cpu) { if (newstates[cpu->cpu_index] == 1) { newstates[cpu->cpu_index] = cur_action; + + target_count++; + last_target = cpu; } cpu = gdb_next_cpu_in_process(cpu); @@ -671,11 +686,25 @@ static int gdb_handle_vcont(const char *p) /* only use if no previous match occourred */ if (newstates[cpu->cpu_index] == 1) { newstates[cpu->cpu_index] = cur_action; + + target_count++; + last_target = cpu; } break; } } + /* + * if we're about to resume a specific set of CPUs/threads, make it so that + * in case execution gets interrupted, we can send GDB a stop reply with a + * correct value. it doesn't really matter which CPU we tell GDB the signal + * happened in (VM pauses stop all of them anyway), so long as it is one of + * the ones we resumed/single stepped here. + */ + if (target_count > 0) { + gdbserver_state.c_cpu = last_target; + } + gdbserver_state.signal = signal; gdb_continue_partial(newstates); return res; -- cgit 1.4.1 From 5b030993dba1bbb841431506c0919c7a7bef986c Mon Sep 17 00:00:00 2001 From: Alex Bennée Date: Tue, 29 Aug 2023 17:15:25 +0100 Subject: gdbstub: remove unused user_ctx field MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This was always NULL so drop it. Reviewed-by: Philippe Mathieu-Daudé Acked-by: Ilya Leoshkevich Signed-off-by: Alex Bennée Message-Id: <20230829161528.2707696-10-alex.bennee@linaro.org> --- gdbstub/gdbstub.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'gdbstub/gdbstub.c') diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index e7d48fa0d4..8e9bc17e07 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -836,7 +836,7 @@ static inline int startswith(const char *string, const char *pattern) return !strncmp(string, pattern, strlen(pattern)); } -static int process_string_cmd(void *user_ctx, const char *data, +static int process_string_cmd(const char *data, const GdbCmdParseEntry *cmds, int num_cmds) { int i; @@ -863,7 +863,7 @@ 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); + cmd->handler(params, NULL); return 0; } @@ -881,7 +881,7 @@ static void run_cmd_parser(const char *data, const GdbCmdParseEntry *cmd) /* In case there was an error during the command parsing we must * send a NULL packet to indicate the command is not supported */ - if (process_string_cmd(NULL, data, cmd, 1)) { + if (process_string_cmd(data, cmd, 1)) { gdb_put_packet(""); } } @@ -1394,7 +1394,7 @@ static void handle_v_commands(GArray *params, void *user_ctx) return; } - if (process_string_cmd(NULL, get_param(params, 0)->data, + if (process_string_cmd(get_param(params, 0)->data, gdb_v_commands_table, ARRAY_SIZE(gdb_v_commands_table))) { gdb_put_packet(""); @@ -1738,13 +1738,13 @@ static void handle_gen_query(GArray *params, void *user_ctx) return; } - if (!process_string_cmd(NULL, get_param(params, 0)->data, + if (!process_string_cmd(get_param(params, 0)->data, gdb_gen_query_set_common_table, ARRAY_SIZE(gdb_gen_query_set_common_table))) { return; } - if (process_string_cmd(NULL, get_param(params, 0)->data, + if (process_string_cmd(get_param(params, 0)->data, gdb_gen_query_table, ARRAY_SIZE(gdb_gen_query_table))) { gdb_put_packet(""); @@ -1757,13 +1757,13 @@ static void handle_gen_set(GArray *params, void *user_ctx) return; } - if (!process_string_cmd(NULL, get_param(params, 0)->data, + if (!process_string_cmd(get_param(params, 0)->data, gdb_gen_query_set_common_table, ARRAY_SIZE(gdb_gen_query_set_common_table))) { return; } - if (process_string_cmd(NULL, get_param(params, 0)->data, + if (process_string_cmd(get_param(params, 0)->data, gdb_gen_set_table, ARRAY_SIZE(gdb_gen_set_table))) { gdb_put_packet(""); -- cgit 1.4.1 From 56e534bd116afda6f7b9ef96691549373c64040d Mon Sep 17 00:00:00 2001 From: Alex Bennée Date: Tue, 29 Aug 2023 17:15:26 +0100 Subject: gdbstub: refactor get_feature_xml MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Alex Bennée Message-Id: <20230829161528.2707696-11-alex.bennee@linaro.org> --- gdbstub/gdbstub.c | 81 +++++++++++++++++++++++++++-------------------------- gdbstub/internals.h | 2 +- 2 files changed, 43 insertions(+), 40 deletions(-) (limited to 'gdbstub/gdbstub.c') diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index 8e9bc17e07..729e54139a 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -354,64 +354,67 @@ static CPUState *gdb_get_cpu(uint32_t pid, uint32_t tid) static const char *get_feature_xml(const char *p, const char **newp, GDBProcess *process) { - size_t len; - int i; - const char *name; CPUState *cpu = gdb_get_first_cpu_in_process(process); CPUClass *cc = CPU_GET_CLASS(cpu); + size_t len; - len = 0; - while (p[len] && p[len] != ':') - len++; - *newp = p + len; + /* + * qXfer:features:read:ANNEX:OFFSET,LENGTH' + * ^p ^newp + */ + char *term = strchr(p, ':'); + *newp = term + 1; + len = term - p; - name = NULL; + /* Is it the main target xml? */ if (strncmp(p, "target.xml", len) == 0) { - char *buf = process->target_xml; - const size_t buf_sz = sizeof(process->target_xml); - - /* Generate the XML description for this CPU. */ - if (!buf[0]) { + if (!process->target_xml) { GDBRegisterState *r; + GString *xml = g_string_new(""); + + g_string_append(xml, + "" + ""); - pstrcat(buf, buf_sz, - "" - "" - ""); if (cc->gdb_arch_name) { - gchar *arch = cc->gdb_arch_name(cpu); - pstrcat(buf, buf_sz, ""); - pstrcat(buf, buf_sz, arch); - pstrcat(buf, buf_sz, ""); - g_free(arch); + g_autofree gchar *arch = cc->gdb_arch_name(cpu); + g_string_append_printf(xml, + "%s", + arch); } - pstrcat(buf, buf_sz, "gdb_core_xml_file); - pstrcat(buf, buf_sz, "\"/>"); + g_string_append(xml, "gdb_core_xml_file); + g_string_append(xml, "\"/>"); for (r = cpu->gdb_regs; r; r = r->next) { - pstrcat(buf, buf_sz, "xml); - pstrcat(buf, buf_sz, "\"/>"); + g_string_append(xml, "xml); + g_string_append(xml, "\"/>"); } - pstrcat(buf, buf_sz, ""); + g_string_append(xml, ""); + + process->target_xml = g_string_free(xml, false); + return process->target_xml; } - return buf; } + /* Is it dynamically generated by the target? */ if (cc->gdb_get_dynamic_xml) { - char *xmlname = g_strndup(p, len); + g_autofree char *xmlname = g_strndup(p, len); const char *xml = cc->gdb_get_dynamic_xml(cpu, xmlname); - - g_free(xmlname); if (xml) { return xml; } } - for (i = 0; ; i++) { - name = xml_builtin[i][0]; - if (!name || (strncmp(name, p, len) == 0 && strlen(name) == len)) - break; + /* Is it one of the encoded gdb-xml/ files? */ + for (int i = 0; xml_builtin[i][0]; i++) { + const char *name = xml_builtin[i][0]; + if ((strncmp(name, p, len) == 0) && + strlen(name) == len) { + return xml_builtin[i][1]; + } } - return name ? xml_builtin[i][1] : NULL; + + /* failed */ + return NULL; } static int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg) @@ -2245,6 +2248,6 @@ void gdb_create_default_process(GDBState *s) process = &s->processes[s->process_num - 1]; process->pid = pid; process->attached = false; - process->target_xml[0] = '\0'; + process->target_xml = NULL; } diff --git a/gdbstub/internals.h b/gdbstub/internals.h index f2b46cce41..4876ebd74f 100644 --- a/gdbstub/internals.h +++ b/gdbstub/internals.h @@ -33,7 +33,7 @@ typedef struct GDBProcess { uint32_t pid; bool attached; - char target_xml[1024]; + char *target_xml; } GDBProcess; enum RSState { -- cgit 1.4.1 From d0e5fa849db4d729e0607ef597cb31eac79532a3 Mon Sep 17 00:00:00 2001 From: Alex Bennée Date: Tue, 29 Aug 2023 17:15:27 +0100 Subject: gdbstub: replace global gdb_has_xml with a function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Richard Henderson Signed-off-by: Alex Bennée Message-Id: <20230829161528.2707696-12-alex.bennee@linaro.org> --- gdbstub/gdbstub.c | 12 +++++++----- gdbstub/internals.h | 1 + gdbstub/softmmu.c | 1 - gdbstub/user.c | 1 - include/exec/gdbstub.h | 10 +++++----- target/arm/gdbstub.c | 8 ++++---- target/ppc/gdbstub.c | 4 ++-- 7 files changed, 19 insertions(+), 18 deletions(-) (limited to 'gdbstub/gdbstub.c') diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index 729e54139a..fdebfe25ea 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -75,8 +75,6 @@ void gdb_init_gdbserver_state(void) gdbserver_state.sstep_flags &= gdbserver_state.supported_sstep_flags; } -bool gdb_has_xml; - /* writes 2*len+1 bytes in buf */ void gdb_memtohex(GString *buf, const uint8_t *mem, int len) { @@ -351,6 +349,11 @@ static CPUState *gdb_get_cpu(uint32_t pid, uint32_t tid) } } +bool gdb_has_xml(void) +{ + return !!gdb_get_cpu_process(gdbserver_state.g_cpu)->target_xml; +} + static const char *get_feature_xml(const char *p, const char **newp, GDBProcess *process) { @@ -1084,7 +1087,7 @@ static void handle_set_reg(GArray *params, void *user_ctx) { int reg_size; - if (!gdb_has_xml) { + if (!gdb_get_cpu_process(gdbserver_state.g_cpu)->target_xml) { gdb_put_packet(""); return; } @@ -1105,7 +1108,7 @@ static void handle_get_reg(GArray *params, void *user_ctx) { int reg_size; - if (!gdb_has_xml) { + if (!gdb_get_cpu_process(gdbserver_state.g_cpu)->target_xml) { gdb_put_packet(""); return; } @@ -1572,7 +1575,6 @@ static void handle_query_xfer_features(GArray *params, void *user_ctx) return; } - gdb_has_xml = true; p = get_param(params, 0)->data; xml = get_feature_xml(p, &p, process); if (!xml) { diff --git a/gdbstub/internals.h b/gdbstub/internals.h index 4876ebd74f..fee243081f 100644 --- a/gdbstub/internals.h +++ b/gdbstub/internals.h @@ -33,6 +33,7 @@ typedef struct GDBProcess { uint32_t pid; bool attached; + /* If gdb sends qXfer:features:read:target.xml this will be populated */ char *target_xml; } GDBProcess; diff --git a/gdbstub/softmmu.c b/gdbstub/softmmu.c index f509b7285d..9f0b8b5497 100644 --- a/gdbstub/softmmu.c +++ b/gdbstub/softmmu.c @@ -97,7 +97,6 @@ static void gdb_chr_event(void *opaque, QEMUChrEvent event) vm_stop(RUN_STATE_PAUSED); replay_gdb_attached(); - gdb_has_xml = false; break; default: break; diff --git a/gdbstub/user.c b/gdbstub/user.c index 5b375be1d9..7ab6e5d975 100644 --- a/gdbstub/user.c +++ b/gdbstub/user.c @@ -198,7 +198,6 @@ static void gdb_accept_init(int fd) gdbserver_state.c_cpu = gdb_first_attached_cpu(); gdbserver_state.g_cpu = gdbserver_state.c_cpu; gdbserver_user_state.fd = fd; - gdb_has_xml = false; } static bool gdb_accept_socket(int gdb_fd) diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h index 7d743fe1e9..0ee39cfdd1 100644 --- a/include/exec/gdbstub.h +++ b/include/exec/gdbstub.h @@ -31,12 +31,12 @@ int gdbserver_start(const char *port_or_device); void gdb_set_stop_cpu(CPUState *cpu); /** - * gdb_has_xml: - * This is an ugly hack to cope with both new and old gdb. - * If gdb sends qXfer:features:read then assume we're talking to a newish - * gdb that understands target descriptions. + * gdb_has_xml() - report of gdb supports modern target descriptions + * + * This will report true if the gdb negotiated qXfer:features:read + * target descriptions. */ -extern bool gdb_has_xml; +bool gdb_has_xml(void); /* in gdbstub-xml.c, generated by scripts/feature_to_c.sh */ extern const char *const xml_builtin[][2]; diff --git a/target/arm/gdbstub.c b/target/arm/gdbstub.c index f421c5d041..8fc8351df7 100644 --- a/target/arm/gdbstub.c +++ b/target/arm/gdbstub.c @@ -48,7 +48,7 @@ int arm_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n) } if (n < 24) { /* FPA registers. */ - if (gdb_has_xml) { + if (gdb_has_xml()) { return 0; } return gdb_get_zeroes(mem_buf, 12); @@ -56,7 +56,7 @@ int arm_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n) switch (n) { case 24: /* FPA status register. */ - if (gdb_has_xml) { + if (gdb_has_xml()) { return 0; } return gdb_get_reg32(mem_buf, 0); @@ -102,7 +102,7 @@ int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n) } if (n < 24) { /* 16-23 */ /* FPA registers (ignored). */ - if (gdb_has_xml) { + if (gdb_has_xml()) { return 0; } return 12; @@ -110,7 +110,7 @@ int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n) switch (n) { case 24: /* FPA status register (ignored). */ - if (gdb_has_xml) { + if (gdb_has_xml()) { return 0; } return 4; diff --git a/target/ppc/gdbstub.c b/target/ppc/gdbstub.c index ca39efdc35..2ad11510bf 100644 --- a/target/ppc/gdbstub.c +++ b/target/ppc/gdbstub.c @@ -56,7 +56,7 @@ static int ppc_gdb_register_len(int n) return sizeof(target_ulong); case 32 ... 63: /* fprs */ - if (gdb_has_xml) { + if (gdb_has_xml()) { return 0; } return 8; @@ -76,7 +76,7 @@ static int ppc_gdb_register_len(int n) return sizeof(target_ulong); case 70: /* fpscr */ - if (gdb_has_xml) { + if (gdb_has_xml()) { return 0; } return sizeof(target_ulong); -- cgit 1.4.1 From 8dd7a4b3487ab93ff8fddc5f818942ff39d4550f Mon Sep 17 00:00:00 2001 From: Alex Bennée Date: Tue, 29 Aug 2023 17:15:28 +0100 Subject: gdbstub: move comment for gdb_register_coprocessor MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use proper kdoc style comments for this API function. Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Richard Henderson Signed-off-by: Alex Bennée Message-Id: <20230829161528.2707696-13-alex.bennee@linaro.org> --- gdbstub/gdbstub.c | 6 ------ include/exec/gdbstub.h | 10 ++++++++++ 2 files changed, 10 insertions(+), 6 deletions(-) (limited to 'gdbstub/gdbstub.c') diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c index fdebfe25ea..349d348c7b 100644 --- a/gdbstub/gdbstub.c +++ b/gdbstub/gdbstub.c @@ -456,12 +456,6 @@ static int gdb_write_register(CPUState *cpu, uint8_t *mem_buf, int reg) return 0; } -/* Register a supplemental set of CPU registers. If g_pos is nonzero it - specifies the first register number and these registers are included in - a standard "g" packet. Direction is relative to gdb, i.e. get_reg is - gdb reading a CPU register, and set_reg is gdb modifying a CPU register. - */ - void gdb_register_coprocessor(CPUState *cpu, gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg, int num_regs, const char *xml, int g_pos) diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h index 0ee39cfdd1..16a139043f 100644 --- a/include/exec/gdbstub.h +++ b/include/exec/gdbstub.h @@ -14,6 +14,16 @@ /* Get or set a register. Returns the size of the register. */ typedef int (*gdb_get_reg_cb)(CPUArchState *env, GByteArray *buf, int reg); typedef int (*gdb_set_reg_cb)(CPUArchState *env, uint8_t *buf, int reg); + +/** + * gdb_register_coprocessor() - register a supplemental set of registers + * @cpu - the CPU associated with registers + * @get_reg - get function (gdb reading) + * @set_reg - set function (gdb modifying) + * @num_regs - number of registers in set + * @xml - xml name of set + * @gpos - non-zero to append to "general" register set at @gpos + */ void gdb_register_coprocessor(CPUState *cpu, gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg, int num_regs, const char *xml, int g_pos); -- cgit 1.4.1