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;
+ 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.
*/
--
2.19.1
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.
--
Luc
>
>> - 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.
>> */
>>
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