Message ID | 20181123091729.29921-4-luc.michel@greensocs.com |
---|---|
State | New |
Headers | show |
Series | gdbstub: support for the multiprocess extension | expand |
Hi Luc, On 23/11/18 10:17, Luc Michel wrote: > The gdb_get_cpu_pid() function does the PID lookup for the given CPU. It > checks if the CPU is a direct child of a CPU cluster. If it is, the > returned PID is the cluster ID plus one (cluster IDs start at 0, GDB > PIDs at 1). When the CPU is not a child of such a container, the PID of > the first process is returned. > > The gdb_fmt_thread_id() function generates the string to be used to identify > a given thread, in a response packet for the peer. This function > supports generating thread IDs when multiprocess mode is enabled (in the > form `p<pid>.<tid>'). > > Use them in the reply to a '?' request. > > Signed-off-by: Luc Michel <luc.michel@greensocs.com> > Acked-by: Alistair Francis <alistair.francis@wdc.com> > Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> > --- > gdbstub.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 58 insertions(+), 2 deletions(-) > > diff --git a/gdbstub.c b/gdbstub.c > index 26f5a7449a..4fbc05dfe3 100644 > --- a/gdbstub.c > +++ b/gdbstub.c > @@ -638,10 +638,52 @@ static int memtox(char *buf, const char *mem, int len) > } > } > return p - buf; > } > > +static uint32_t gdb_get_cpu_pid(const GDBState *s, CPUState *cpu) > +{ > +#ifndef CONFIG_USER_ONLY > + gchar *path, *name; Setting ... gchar *path, *name = NULL; > + Object *obj; > + CPUClusterState *cluster; > + uint32_t ret; > + > + path = object_get_canonical_path(OBJECT(cpu)); > + name = object_get_canonical_path_component(OBJECT(cpu)); ... we might move this line ... > + > + if (path == NULL) { > + ret = s->processes[0].pid; > + goto out; > + } ... here: name = object_get_canonical_path_component(OBJECT(cpu)); > + > + /* > + * Retrieve the CPU parent path by removing the last '/' and the CPU name > + * from the CPU canonical path. */ > + path[strlen(path) - strlen(name) - 1] = '\0'; Can we get there with path != NULL && name == NULL? > + > + obj = object_resolve_path_type(path, TYPE_CPU_CLUSTER, NULL); > + > + if (obj == NULL) { > + ret = s->processes[0].pid; > + goto out; > + } > + > + cluster = CPU_CLUSTER(obj); > + ret = cluster->cluster_id + 1; > + > +out: > + g_free(name); > + g_free(path); > + > + return ret; > + > +#else [*] > + return s->processes[0].pid; > +#endif > +} > + > static const char *get_feature_xml(const char *p, const char **newp, > CPUClass *cc) > { > size_t len; > int i; > @@ -907,10 +949,23 @@ static CPUState *find_cpu(uint32_t thread_id) > } > > return NULL; > } > > +static char *gdb_fmt_thread_id(const GDBState *s, CPUState *cpu, > + char *buf, size_t buf_size) > +{ > + if (s->multiprocess) { > + snprintf(buf, buf_size, "p%02x.%02x", > + gdb_get_cpu_pid(s, cpu), cpu_gdb_index(cpu)); > + } else { > + snprintf(buf, buf_size, "%02x", cpu_gdb_index(cpu)); > + } > + > + return buf; > +} > + > static int is_query_packet(const char *p, const char *query, char separator) > { > unsigned int query_len = strlen(query); > > return strncmp(p, query, query_len) == 0 && > @@ -1018,22 +1073,23 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf) > const char *p; > uint32_t thread; > int ch, reg_size, type, res; > uint8_t mem_buf[MAX_PACKET_LENGTH]; > char buf[sizeof(mem_buf) + 1 /* trailing NUL */]; > + char thread_id[16]; > uint8_t *registers; > target_ulong addr, len; > > trace_gdbstub_io_command(line_buf); > > p = line_buf; > ch = *p++; > switch(ch) { > case '?': > /* TODO: Make this return the correct value for user-mode. */ Is this comment still relevant? If so, wouldn't it be better placed in [*]? > - snprintf(buf, sizeof(buf), "T%02xthread:%02x;", GDB_SIGNAL_TRAP, > - cpu_gdb_index(s->c_cpu)); > + snprintf(buf, sizeof(buf), "T%02xthread:%s;", GDB_SIGNAL_TRAP, > + gdb_fmt_thread_id(s, s->c_cpu, thread_id, sizeof(thread_id))); > put_packet(s, buf); > /* Remove all the breakpoints when this query is issued, > * because gdb is doing and initial connect and the state > * should be cleaned up. > */ >
On 11/25/18 10:22 PM, Philippe Mathieu-Daudé wrote: > Hi Luc, > > On 23/11/18 10:17, Luc Michel wrote: >> The gdb_get_cpu_pid() function does the PID lookup for the given CPU. It >> checks if the CPU is a direct child of a CPU cluster. If it is, the >> returned PID is the cluster ID plus one (cluster IDs start at 0, GDB >> PIDs at 1). When the CPU is not a child of such a container, the PID of >> the first process is returned. >> >> The gdb_fmt_thread_id() function generates the string to be used to identify >> a given thread, in a response packet for the peer. This function >> supports generating thread IDs when multiprocess mode is enabled (in the >> form `p<pid>.<tid>'). >> >> Use them in the reply to a '?' request. >> >> Signed-off-by: Luc Michel <luc.michel@greensocs.com> >> Acked-by: Alistair Francis <alistair.francis@wdc.com> >> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> >> --- >> gdbstub.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- >> 1 file changed, 58 insertions(+), 2 deletions(-) >> >> diff --git a/gdbstub.c b/gdbstub.c >> index 26f5a7449a..4fbc05dfe3 100644 >> --- a/gdbstub.c >> +++ b/gdbstub.c >> @@ -638,10 +638,52 @@ static int memtox(char *buf, const char *mem, int len) >> } >> } >> return p - buf; >> } >> >> +static uint32_t gdb_get_cpu_pid(const GDBState *s, CPUState *cpu) >> +{ >> +#ifndef CONFIG_USER_ONLY >> + gchar *path, *name; > > Setting ... > > gchar *path, *name = NULL; > >> + Object *obj; >> + CPUClusterState *cluster; >> + uint32_t ret; >> + >> + path = object_get_canonical_path(OBJECT(cpu)); >> + name = object_get_canonical_path_component(OBJECT(cpu)); > > ... we might move this line ... > >> + >> + if (path == NULL) { >> + ret = s->processes[0].pid; >> + goto out; >> + } > > ... hereOK I'll change that. > > name = object_get_canonical_path_component(OBJECT(cpu)); > >> + >> + /* >> + * Retrieve the CPU parent path by removing the last '/' and the CPU name >> + * from the CPU canonical path. */ >> + path[strlen(path) - strlen(name) - 1] = '\0'; > > Can we get there with path != NULL && name == NULL? I think the only way we could end up in this case is if cpu == object_get_root(), which does not make much sense. I can add an assert(name != NULL) here to enforce that. > >> + >> + obj = object_resolve_path_type(path, TYPE_CPU_CLUSTER, NULL); >> + >> + if (obj == NULL) { >> + ret = s->processes[0].pid; >> + goto out; >> + } >> + >> + cluster = CPU_CLUSTER(obj); >> + ret = cluster->cluster_id + 1; >> + >> +out: >> + g_free(name); >> + g_free(path); >> + >> + return ret; >> + >> +#else > > [*] > >> + return s->processes[0].pid; >> +#endif >> +} >> + >> static const char *get_feature_xml(const char *p, const char **newp, >> CPUClass *cc) >> { >> size_t len; >> int i; >> @@ -907,10 +949,23 @@ static CPUState *find_cpu(uint32_t thread_id) >> } >> >> return NULL; >> } >> >> +static char *gdb_fmt_thread_id(const GDBState *s, CPUState *cpu, >> + char *buf, size_t buf_size) >> +{ >> + if (s->multiprocess) { >> + snprintf(buf, buf_size, "p%02x.%02x", >> + gdb_get_cpu_pid(s, cpu), cpu_gdb_index(cpu)); >> + } else { >> + snprintf(buf, buf_size, "%02x", cpu_gdb_index(cpu)); >> + } >> + >> + return buf; >> +} >> + >> static int is_query_packet(const char *p, const char *query, char separator) >> { >> unsigned int query_len = strlen(query); >> >> return strncmp(p, query, query_len) == 0 && >> @@ -1018,22 +1073,23 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf) >> const char *p; >> uint32_t thread; >> int ch, reg_size, type, res; >> uint8_t mem_buf[MAX_PACKET_LENGTH]; >> char buf[sizeof(mem_buf) + 1 /* trailing NUL */]; >> + char thread_id[16]; >> uint8_t *registers; >> target_ulong addr, len; >> >> trace_gdbstub_io_command(line_buf); >> >> p = line_buf; >> ch = *p++; >> switch(ch) { >> case '?': >> /* TODO: Make this return the correct value for user-mode. */ > > Is this comment still relevant? > > If so, wouldn't it be better placed in [*]? git blame shows that at the time when this comment was added (1fddef4b1ba from 2005), the Stop Reply packet was like this: + /* TODO: Make this return the correct value for user-mode. */ snprintf(buf, sizeof(buf), "S%02x", SIGTRAP); Which is the form that contains only a signal number. So this comment must refer to this hard-coded signal, so I think it is still valid :-) However, you are right pointing out that the PID used in user-mode should probably be the one of the QEMU process running the guest binary (as it is done for TIDs I believe). I'll add a comment at [*] to point that out. Thanks.
diff --git a/gdbstub.c b/gdbstub.c index 26f5a7449a..4fbc05dfe3 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -638,10 +638,52 @@ static int memtox(char *buf, const char *mem, int len) } } return p - buf; } +static uint32_t gdb_get_cpu_pid(const GDBState *s, CPUState *cpu) +{ +#ifndef CONFIG_USER_ONLY + gchar *path, *name; + Object *obj; + CPUClusterState *cluster; + uint32_t ret; + + path = object_get_canonical_path(OBJECT(cpu)); + name = object_get_canonical_path_component(OBJECT(cpu)); + + if (path == NULL) { + ret = s->processes[0].pid; + goto out; + } + + /* + * Retrieve the CPU parent path by removing the last '/' and the CPU name + * from the CPU canonical path. */ + path[strlen(path) - strlen(name) - 1] = '\0'; + + obj = object_resolve_path_type(path, TYPE_CPU_CLUSTER, NULL); + + if (obj == NULL) { + ret = s->processes[0].pid; + goto out; + } + + cluster = CPU_CLUSTER(obj); + ret = cluster->cluster_id + 1; + +out: + g_free(name); + g_free(path); + + return ret; + +#else + return s->processes[0].pid; +#endif +} + static const char *get_feature_xml(const char *p, const char **newp, CPUClass *cc) { size_t len; int i; @@ -907,10 +949,23 @@ static CPUState *find_cpu(uint32_t thread_id) } return NULL; } +static char *gdb_fmt_thread_id(const GDBState *s, CPUState *cpu, + char *buf, size_t buf_size) +{ + if (s->multiprocess) { + snprintf(buf, buf_size, "p%02x.%02x", + gdb_get_cpu_pid(s, cpu), cpu_gdb_index(cpu)); + } else { + snprintf(buf, buf_size, "%02x", cpu_gdb_index(cpu)); + } + + return buf; +} + static int is_query_packet(const char *p, const char *query, char separator) { unsigned int query_len = strlen(query); return strncmp(p, query, query_len) == 0 && @@ -1018,22 +1073,23 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf) const char *p; uint32_t thread; int ch, reg_size, type, res; uint8_t mem_buf[MAX_PACKET_LENGTH]; char buf[sizeof(mem_buf) + 1 /* trailing NUL */]; + char thread_id[16]; uint8_t *registers; target_ulong addr, len; trace_gdbstub_io_command(line_buf); p = line_buf; ch = *p++; switch(ch) { case '?': /* TODO: Make this return the correct value for user-mode. */ - snprintf(buf, sizeof(buf), "T%02xthread:%02x;", GDB_SIGNAL_TRAP, - cpu_gdb_index(s->c_cpu)); + snprintf(buf, sizeof(buf), "T%02xthread:%s;", GDB_SIGNAL_TRAP, + gdb_fmt_thread_id(s, s->c_cpu, thread_id, sizeof(thread_id))); put_packet(s, buf); /* Remove all the breakpoints when this query is issued, * because gdb is doing and initial connect and the state * should be cleaned up. */