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

[Warner Losh]

> 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.

Warner

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