On 04.02.20 14:27, Thomas Huth wrote:
>> +/*
>> + * Low level uv_call that takes r1 and r2 as parameter and avoids
>> + * stalls for long running busy conditions by doing schedule
>> + */
>> +static inline int uv_call_sched(unsigned long r1, unsigned long r2)
>> +{
>> + int cc = 3;
>> +
>> + while (cc > 1) {
>> + asm volatile(
>> + "0: .insn rrf,0xB9A40000,%[r1],%[r2],0,0\n"
>> + " ipm %[cc]\n"
>> + " srl %[cc],28\n"
>> + : [cc] "=d" (cc)
>> + : [r1] "a" (r1), [r2] "a" (r2)
>
> You could use "d" instead of "a" for both, r1 and r2, here.
Indeed. Fixed.
>
>> + : "memory", "cc");
>> + if (need_resched())
>> + schedule();
>> + }
>
> It's a matter of taste, but I'd rather do:
>
> int cc;
> do {
> ...
> } while (cc > 1);
>
> (i.e. no need to pre-initialize cc with 3)
Yes, I like that better.
>
>> + return cc;
>> +}
>
> Thomas
>
