Commit 1a227336 authored by Luc Michel's avatar Luc Michel Committed by Peter Maydell
Browse files

gdbstub: add multiprocess support to '?' packets 



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 default 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: default avatarLuc Michel <luc.michel@greensocs.com>
Acked-by: default avatarAlistair Francis <alistair.francis@wdc.com>
Reviewed-by: default avatarEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 20181207090135.7651-4-luc.michel@greensocs.com
[PMM: fixed checkpatch blockquote style nit]
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent 8f468636

gdbstub.c

+64 −2
Original line number Diff line number Diff line
@@ -640,6 +640,54 @@ 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 = NULL;

    Object *obj;

    CPUClusterState *cluster;

    uint32_t ret;



    path = object_get_canonical_path(OBJECT(cpu));



    if (path == NULL) {

        /* Return the default process' PID */

        ret = s->processes[s->process_num - 1].pid;

        goto out;

    }



    name = object_get_canonical_path_component(OBJECT(cpu));

    assert(name != NULL);



    /*

     * 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) {

        /* Return the default process' PID */

        ret = s->processes[s->process_num - 1].pid;

        goto out;

    }



    cluster = CPU_CLUSTER(obj);

    ret = cluster->cluster_id + 1;



out:

    g_free(name);

    g_free(path);



    return ret;



#else

    /* TODO: In user mode, we should use the task state PID */

    return s->processes[s->process_num - 1].pid;

#endif

}



static const char *get_feature_xml(const char *p, const char **newp,

                                   CPUClass *cc)

{
@@ -909,6 +957,19 @@ 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);
@@ -1020,6 +1081,7 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf) 
    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;
@@ -1030,8 +1092,8 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf) 
    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