Re: [PATCH v3 3/9] gdbstub: Add support for target-specific stubs

[Gustavo Romero <gustavo.romero@linaro.org>]

Hi Alex,

On 6/21/24 5:11 AM, Alex Bennée wrote:
> Gustavo Romero <gustavo.romero@linaro.org> writes:
> 
>> Currently, it's not possible to have stubs specific to a given target,
>> even though there are GDB features which are target-specific, like, for
>> instance, memory tagging.
>>
>> This commit introduces gdb_extend_qsupported_features,
>> gdb_extend_query_table, and gdb_extend_set_table functions as interfaces
>> to extend the qSupported string, the query handler table, and the set
>> handler table, allowing target-specific stub implementations.
>>
>> Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
>> ---
>>   gdbstub/gdbstub.c          | 59 ++++++++++++++++++++++++++++++++++----
>>   include/gdbstub/commands.h | 22 ++++++++++++++
>>   2 files changed, 75 insertions(+), 6 deletions(-)
>>
>> diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
>> index 9ff2f4177d..e69cc5131e 100644
>> --- a/gdbstub/gdbstub.c
>> +++ b/gdbstub/gdbstub.c
>> @@ -1609,6 +1609,12 @@ static void handle_query_thread_extra(GArray *params, void *user_ctx)
>>       gdb_put_strbuf();
>>   }
>>   
>> +static char *extended_qsupported_features;
>> +void gdb_extend_qsupported_features(char *qsupported_features)
>> +{
> 
>    /*
>     * We don't support different sets of CPU gdb features on different
>     * CPUs yet so assert things are the same.
>     */
> 
>     g_assert(!extended_qsupported_features ||
>     g_strcmp0(extended_qsupported_features, qsupported_features) == 0)
>
Done in v4. Thanks.


Cheers,
Gustavo

  
>> +    extended_qsupported_features = qsupported_features;
>> +}
>> +
>>   static void handle_query_supported(GArray *params, void *user_ctx)
>>   {
>>       CPUClass *cc;
>> @@ -1648,6 +1654,11 @@ static void handle_query_supported(GArray *params, void *user_ctx)
>>       }
>>   
>>       g_string_append(gdbserver_state.str_buf, ";vContSupported+;multiprocess+");
>> +
>> +    if (extended_qsupported_features) {
>> +        g_string_append(gdbserver_state.str_buf, extended_qsupported_features);
>> +    }
>> +
>>       gdb_put_strbuf();
>>   }
>>   
>> @@ -1729,6 +1740,14 @@ static const GdbCmdParseEntry gdb_gen_query_set_common_table[] = {
>>       },
>>   };
>>   
>> +static GdbCmdParseEntry *extended_query_table;
>> +static int extended_query_table_size;
>> +void gdb_extend_query_table(GdbCmdParseEntry *table, int size)
>> +{
>> +    extended_query_table = table;
>> +    extended_query_table_size = size;
> 
> Similar assert here.
> 
>> +}
>> +
>>   static const GdbCmdParseEntry gdb_gen_query_table[] = {
>>       {
>>           .handler = handle_query_curr_tid,
>> @@ -1821,6 +1840,14 @@ static const GdbCmdParseEntry gdb_gen_query_table[] = {
>>   #endif
>>   };
>>   
>> +static GdbCmdParseEntry *extended_set_table;
>> +static int extended_set_table_size;
>> +void gdb_extend_set_table(GdbCmdParseEntry *table, int size)
>> +{
> 
> ditto
> 
>> +    extended_set_table = table;
>> +    extended_set_table_size = size;
>> +}
>> +
>>   static const GdbCmdParseEntry gdb_gen_set_table[] = {
>>       /* Order is important if has same prefix */
>>       {
>> @@ -1859,11 +1886,21 @@ static void handle_gen_query(GArray *params, void *user_ctx)
>>           return;
>>       }
>>   
>> -    if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
>> -                            gdb_gen_query_table,
>> -                            ARRAY_SIZE(gdb_gen_query_table))) {
>> -        gdb_put_packet("");
>> +    if (process_string_cmd(gdb_get_cmd_param(params, 0)->data,
>> +                           gdb_gen_query_table,
>> +                           ARRAY_SIZE(gdb_gen_query_table))) {
>> +        return;
>> +    }
>> +
>> +    if (extended_query_table &&
>> +        process_string_cmd(gdb_get_cmd_param(params, 0)->data,
>> +                           extended_query_table,
>> +                           extended_query_table_size)) {
>> +        return;
>>       }
>> +
>> +    /* Can't handle query, return Empty response. */
>> +    gdb_put_packet("");
>>   }
>>   
>>   static void handle_gen_set(GArray *params, void *user_ctx)
>> @@ -1878,11 +1915,21 @@ static void handle_gen_set(GArray *params, void *user_ctx)
>>           return;
>>       }
>>   
>> -    if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
>> +    if (process_string_cmd(gdb_get_cmd_param(params, 0)->data,
>>                              gdb_gen_set_table,
>>                              ARRAY_SIZE(gdb_gen_set_table))) {
>> -        gdb_put_packet("");
>> +        return;
>>       }
>> +
>> +    if (extended_set_table &&
>> +        process_string_cmd(gdb_get_cmd_param(params, 0)->data,
>> +                           extended_set_table,
>> +                           extended_set_table_size)) {
>> +        return;
>> +    }
>> +
>> +    /* Can't handle set, return Empty response. */
>> +    gdb_put_packet("");
>>   }
>>   
>>   static void handle_target_halt(GArray *params, void *user_ctx)
>> diff --git a/include/gdbstub/commands.h b/include/gdbstub/commands.h
>> index dd45c38472..2204c3ddbe 100644
>> --- a/include/gdbstub/commands.h
>> +++ b/include/gdbstub/commands.h
>> @@ -71,4 +71,26 @@ typedef struct GdbCmdParseEntry {
>>    */
>>   int gdb_put_packet(const char *buf);
>>   
>> +/**
>> + * gdb_extend_query_table() - Extend query table.
>> + * @table: The table with the additional query packet handlers.
>> + * @size: The number of handlers to be added.
>> + */
>> +void gdb_extend_query_table(GdbCmdParseEntry *table, int size);
>> +
>> +/**
>> + * gdb_extend_set_table() - Extend set table.
>> + * @table: The table with the additional set packet handlers.
>> + * @size: The number of handlers to be added.
>> + */
>> +void gdb_extend_set_table(GdbCmdParseEntry *table, int size);
>> +
>> +/**
>> + * gdb_extend_qsupported_features() - Extend the qSupported features string.
>> + * @qsupported_features: The additional qSupported feature(s) string. The string
>> + * should start with a semicolon and, if there are more than one feature, the
>> + * features should be separate by a semiocolon.
>> + */
>> +void gdb_extend_qsupported_features(char *qsupported_features);
>> +
>>   #endif /* GDBSTUB_COMMANDS_H */
> 
> Otherwise:
> 
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>