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

[Warner Losh <wlosh@bsdimp.com>]

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> On Aug 27, 2021, at 10:00 AM, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> 
> 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 :)

OK. I’ll drop and queue up next time.

Warner


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