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From: Gustavo Romero <gustavo.romero@linaro.org>
To: "Alex Bennée" <alex.bennee@linaro.org>
Cc: qemu-devel@nongnu.org, philmd@linaro.org,
	peter.maydell@linaro.org, richard.henderson@linaro.org
Subject: Re: [PATCH v2 3/9] gdbstub: Add support for target-specific stubs
Date: Mon, 17 Jun 2024 03:33:29 -0300	[thread overview]
Message-ID: <c80bfaab-7974-bc0f-c66f-96d75e2d7e2b@linaro.org> (raw)
In-Reply-To: <871q4zvk5o.fsf@draig.linaro.org>

Hi Alex,

On 6/14/24 8:27 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)
>> +{
> 
> Maybe g_assert(!extended_qsupported_features)?
> 
>> +    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)
>> +{
> 
> g_assert(!extended_query_table)
> 
>> +    extended_query_table = table;
>> +    extended_query_table_size = size;
>> +}
>> +
>>   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)
>> +{
>> +    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);
>> +
> 
> We should make it clear these functions should only be called once
> (although I guess in a heterogeneous future we might have to do something
> more clever).

There a some cases where actually the API functions are called multiple
times it looks like. For instance, the assert is hit in the following test:

$ ./build/qemu-aarch64 ./build/tests/tcg/aarch64-linux-user/munmap-pthread

Probably because pthread_create is involved, but I can't explain it yet.


Cheers,
Gustavo


  reply	other threads:[~2024-06-17  6:34 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-13 17:20 [PATCH v2 0/9] Add MTE stubs for aarch64 user mode Gustavo Romero
2024-06-13 17:20 ` [PATCH v2 1/9] gdbstub: Clean up process_string_cmd Gustavo Romero
2024-06-14 11:24   ` Alex Bennée
2024-06-13 17:20 ` [PATCH v2 2/9] gdbstub: Move GdbCmdParseEntry into a new header file Gustavo Romero
2024-06-14 11:25   ` Alex Bennée
2024-06-13 17:20 ` [PATCH v2 3/9] gdbstub: Add support for target-specific stubs Gustavo Romero
2024-06-14 11:27   ` Alex Bennée
2024-06-17  6:33     ` Gustavo Romero [this message]
2024-06-17  9:41       ` Alex Bennée
2024-06-13 17:20 ` [PATCH v2 4/9] target/arm: Fix exception case in allocation_tag_mem_probe Gustavo Romero
2024-06-14 11:29   ` Alex Bennée
2024-06-13 17:20 ` [PATCH v2 5/9] target/arm: Make some MTE helpers widely available Gustavo Romero
2024-06-13 17:32   ` Philippe Mathieu-Daudé
2024-06-13 18:13     ` Gustavo Romero
2024-06-14 12:34       ` Philippe Mathieu-Daudé
2024-06-17  6:37         ` Gustavo Romero
2024-06-13 17:21 ` [PATCH v2 6/9] target/arm: Factor out code for setting MTE TCF0 field Gustavo Romero
2024-06-13 17:35   ` Philippe Mathieu-Daudé
2024-06-13 18:15     ` Gustavo Romero
2024-06-14  9:02       ` Philippe Mathieu-Daudé
2024-06-17  6:56         ` Gustavo Romero
2024-06-14 11:21   ` Alex Bennée
2024-06-13 17:21 ` [PATCH v2 7/9] gdbstub: Make get cpu and hex conversion functions non-internal Gustavo Romero
2024-06-14 11:34   ` Alex Bennée
2024-06-13 17:21 ` [PATCH v2 8/9] gdbstub: Add support for MTE in user mode Gustavo Romero
2024-06-14 10:51   ` Alex Bennée
2024-06-14 16:16     ` Gustavo Romero
2024-06-13 17:21 ` [PATCH v2 9/9] tests/tcg/aarch64: Add MTE gdbstub tests Gustavo Romero
2024-06-14 11:42   ` Alex Bennée
2024-06-14 15:58     ` Gustavo Romero
2024-06-14 15:49 ` [PATCH v2 0/9] Add MTE stubs for aarch64 user mode Alex Bennée
2024-06-14 16:01   ` Gustavo Romero
2024-06-17  7:02   ` Gustavo Romero
2024-06-17  9:50     ` Alex Bennée
2024-06-24  5:40       ` Gustavo Romero

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