Re: [PATCH v2 41/43] bsd-user: Implement cpu_copy() helper routine

[Philippe Mathieu-Daudé]

On 8/27/21 4:56 PM, Warner Losh wrote:
>> On Aug 26, 2021, at 10:47 PM, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>>
>> On 8/26/21 11:11 PM, imp@bsdimp.com wrote:
>>> From: Warner Losh <imp@FreeBSD.org>
>>>
>>> cpu_copy shouldbe called when processes are creating new threads. It
>>
>> Typo "should be"
>>
>>> copies the current state of the CPU to a new cpu state needed for the
>>> new thread.
>>>
>>> Signed-off-by: Stacey Son <sson@FreeBSD.org>
>>> Signed-off-by: Warner Losh <imp@bsdimp.com>
>>> Signed-off-by: Justin Hibbits <chmeeedalf@gmail.com>
>>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>>> ---
>>> bsd-user/main.c | 30 ++++++++++++++++++++++++++++++
>>> 1 file changed, 30 insertions(+)
>>>
>>> diff --git a/bsd-user/main.c b/bsd-user/main.c
>>> index e2ed9e32ba..b35bcf4d1e 100644
>>> --- a/bsd-user/main.c
>>> +++ b/bsd-user/main.c
>>> @@ -180,6 +180,36 @@ void init_task_state(TaskState *ts)
>>>     ts->sigqueue_table[i].next = NULL;
>>> }
>>>
>>> +CPUArchState *cpu_copy(CPUArchState *env)
>>> +{
>>> +    CPUState *cpu = env_cpu(env);
>>> +    CPUState *new_cpu = cpu_create(cpu_type);
>>> +    CPUArchState *new_env = new_cpu->env_ptr;
>>> +    CPUBreakpoint *bp;
>>> +    CPUWatchpoint *wp;
>>> +
>>> +    /* Reset non arch specific state */
>>> +    cpu_reset(new_cpu);
>>> +
>>> +    memcpy(new_env, env, sizeof(CPUArchState));
>>> +
>>> +    /*
>>> +     * Clone all break/watchpoints.
>>> +     * Note: Once we support ptrace with hw-debug register access, make 
>>> sure
>>> +     * BP_CPU break/watchpoints are handled correctly on clone.
>>> +     */
>>> +    QTAILQ_INIT(&cpu->breakpoints);
>>> +    QTAILQ_INIT(&cpu->watchpoints);
>>> +    QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
>>> +        cpu_breakpoint_insert(new_cpu, bp->pc, bp->flags, NULL);
>>> +    }
>>> +    QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
>>> +        cpu_watchpoint_insert(new_cpu, wp->vaddr, wp->len, wp->flags, 
>>> NULL);
>>> +    }
>>> +
>>> +    return new_env;
>>> +}
>>
>> But where is it called?
> 
> It’s in the bsd-user fork’d proc code:
> 
> https://github.com/qemu-bsd-user/qemu-bsd-user/blob/079d45942db8d1038806cb459992b4f016b52b51/bsd-user/freebsd/os-thread.c#L1566
> 
> Is where it’s called from. I wanted to get it out of the way in this review 
> since I was trying to get all the changes to main.c done, but if you’d like, 
> I can drop it and submit in the next round.

Better keep it for next round :)