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Re: [Qemu-devel] [PATCH v8 05/16] gdbstub: add multiprocess support to v
From: |
Luc Michel |
Subject: |
Re: [Qemu-devel] [PATCH v8 05/16] gdbstub: add multiprocess support to vCont packets |
Date: |
Fri, 22 Mar 2019 15:01:30 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.3 |
On 3/22/19 2:29 PM, Jan Kiszka wrote:
> On 07.12.18 10:01, Luc Michel wrote:
>> Add the gdb_first_attached_cpu() and gdb_next_attached_cpu() to iterate
>> over all the CPUs in currently attached processes.
>>
>> Add the gdb_first_cpu_in_process() and gdb_next_cpu_in_process() to
>> iterate over CPUs of a given process.
>>
>> Use them to add multiprocess extension support to vCont packets.
>>
>> Signed-off-by: Luc Michel <address@hidden>
>> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
>> Reviewed-by: Edgar E. Iglesias <address@hidden>
>> Acked-by: Alistair Francis <address@hidden>
>> ---
>> gdbstub.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++-------
>> 1 file changed, 102 insertions(+), 15 deletions(-)
>>
>> diff --git a/gdbstub.c b/gdbstub.c
>> index 911faa225a..77b3dbb2c8 100644
>> --- a/gdbstub.c
>> +++ b/gdbstub.c
>> @@ -721,10 +721,40 @@ static CPUState *find_cpu(uint32_t thread_id)
>> }
>>
>> return NULL;
>> }
>>
>> +static CPUState *get_first_cpu_in_process(const GDBState *s,
>> + GDBProcess *process)
>> +{
>> + CPUState *cpu;
>> +
>> + CPU_FOREACH(cpu) {
>> + if (gdb_get_cpu_pid(s, cpu) == process->pid) {
>> + return cpu;
>> + }
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static CPUState *gdb_next_cpu_in_process(const GDBState *s, CPUState *cpu)
>> +{
>> + uint32_t pid = gdb_get_cpu_pid(s, cpu);
>> + cpu = CPU_NEXT(cpu);
>> +
>> + while (cpu) {
>> + if (gdb_get_cpu_pid(s, cpu) == pid) {
>> + break;
>> + }
>> +
>> + cpu = CPU_NEXT(cpu);
>> + }
>> +
>> + return cpu;
>> +}
>> +
>> static CPUState *gdb_get_cpu(const GDBState *s, uint32_t pid, uint32_t tid)
>> {
>> GDBProcess *process;
>> CPUState *cpu;
>>
>> @@ -750,10 +780,41 @@ static CPUState *gdb_get_cpu(const GDBState *s,
>> uint32_t pid, uint32_t tid)
>> }
>>
>> return cpu;
>> }
>>
>> +/* Return the cpu following @cpu, while ignoring
>> + * unattached processes.
>> + */
>> +static CPUState *gdb_next_attached_cpu(const GDBState *s, CPUState *cpu)
>> +{
>> + cpu = CPU_NEXT(cpu);
>> +
>> + while (cpu) {
>> + if (gdb_get_cpu_process(s, cpu)->attached) {
>> + break;
>> + }
>> +
>> + cpu = CPU_NEXT(cpu);
>> + }
>> +
>> + return cpu;
>> +}
>> +
>> +/* Return the first attached cpu */
>> +static CPUState *gdb_first_attached_cpu(const GDBState *s)
>> +{
>> + CPUState *cpu = first_cpu;
>> + GDBProcess *process = gdb_get_cpu_process(s, cpu);
>> +
>> + if (!process->attached) {
>> + return gdb_next_attached_cpu(s, cpu);
>> + }
>> +
>> + return cpu;
>> +}
>> +
>> static const char *get_feature_xml(const char *p, const char **newp,
>> CPUClass *cc)
>> {
>> size_t len;
>> int i;
>> @@ -1088,14 +1149,16 @@ static int is_query_packet(const char *p, const char
>> *query, char separator)
>> * returns -ENOTSUP if a command is unsupported, -EINVAL or -ERANGE if
>> there is
>> * a format error, 0 on success.
>> */
>> static int gdb_handle_vcont(GDBState *s, const char *p)
>> {
>> - int res, idx, signal = 0;
>> + int res, signal = 0;
>> char cur_action;
>> char *newstates;
>> unsigned long tmp;
>> + uint32_t pid, tid;
>> + GDBProcess *process;
>> CPUState *cpu;
>> #ifdef CONFIG_USER_ONLY
>> int max_cpus = 1; /* global variable max_cpus exists only in system
>> mode */
>>
>> CPU_FOREACH(cpu) {
>> @@ -1134,29 +1197,52 @@ static int gdb_handle_vcont(GDBState *s, const char
>> *p)
>> } else if (cur_action != 'c' && cur_action != 's') {
>> /* unknown/invalid/unsupported command */
>> res = -ENOTSUP;
>> goto out;
>> }
>> - /* thread specification. special values: (none), -1 = all; 0 = any
>> */
>> - if ((p[0] == ':' && p[1] == '-' && p[2] == '1') || (p[0] != ':')) {
>> - if (*p == ':') {
>> - p += 3;
>> - }
>> - for (idx = 0; idx < max_cpus; idx++) {
>> - if (newstates[idx] == 1) {
>> - newstates[idx] = cur_action;
>> +
>> + if (*p++ != ':') {
>> + res = -ENOTSUP;
>> + goto out;
>> + }
>> +
>> + switch (read_thread_id(p, &p, &pid, &tid)) {
>> + case GDB_READ_THREAD_ERR:
>> + res = -EINVAL;
>> + goto out;
>> +
>> + case GDB_ALL_PROCESSES:
>> + cpu = gdb_first_attached_cpu(s);
>> + while (cpu) {
>> + if (newstates[cpu->cpu_index] == 1) {
>> + newstates[cpu->cpu_index] = cur_action;
>> }
>> +
>> + cpu = gdb_next_attached_cpu(s, cpu);
>> }
>> - } else if (*p == ':') {
>> - p++;
>> - res = qemu_strtoul(p, &p, 16, &tmp);
>> - if (res) {
>> + break;
>> +
>> + case GDB_ALL_THREADS:
>> + process = gdb_get_process(s, pid);
>> +
>> + if (!process->attached) {
>> + res = -EINVAL;
>> goto out;
>> }
>>
>> - /* 0 means any thread, so we pick the first valid CPU */
>> - cpu = tmp ? find_cpu(tmp) : first_cpu;
>> + cpu = get_first_cpu_in_process(s, process);
>> + while (cpu) {
>> + if (newstates[cpu->cpu_index] == 1) {
>> + newstates[cpu->cpu_index] = cur_action;
>> + }
>> +
>> + cpu = gdb_next_cpu_in_process(s, cpu);
>> + }
>> + break;
>> +
>> + case GDB_ONE_THREAD:
>> + cpu = gdb_get_cpu(s, pid, tid);
>>
>> /* invalid CPU/thread specified */
>> if (!cpu) {
>> res = -EINVAL;
>> goto out;
>> @@ -1164,10 +1250,11 @@ static int gdb_handle_vcont(GDBState *s, const char
>> *p)
>>
>> /* only use if no previous match occourred */
>> if (newstates[cpu->cpu_index] == 1) {
>> newstates[cpu->cpu_index] = cur_action;
>> }
>> + break;
>> }
>> }
>> s->signal = signal;
>> gdb_continue_partial(s, newstates);
>>
>>
>
> This breaks system-level debugging with gdb, at least with version
> 7.7.50 and for x86 targets.
I think it's related to
https://www.mail-archive.com/address@hidden/msg601065.html
[snip]
> Sending packet: $vCont;s:1;c#c1...Ack
> Packet received: E22
> warning: Remote failure reply: E22
[snip]
The vCont packet does not specifies a thread-id for the last action.
This is a valid syntax, incorrectly treated as an error by the stub.
Lucien: do you plan to send a re-roll? Otherwise I'll do it on next
Monday (25/03) because I would like this bug to be fixed before it hits 4.0.
Thanks.
--
Luc