Re: [PATCH 4/6] s390: add system call to run tasks with modified branch prediction

[Christian Borntraeger]

On 01/17/2018 11:03 AM, Florian Weimer wrote:
> On 01/17/2018 10:48 AM, Martin Schwidefsky wrote:
>> ÂÂÂÂÂÂÂÂ rc = syscall(__NR_s390_modify_bp);
>> ÂÂÂÂÂÂÂÂ if (rc) {
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ perror("s390_modify_bp");
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ exit(EXIT_FAILURE);
>> ÂÂÂÂÂÂÂÂ }
> 
> Isn't this traditionally done through personality or prctl?

I think we want this per thread (and not per process). So I assume personality
will not work out. Can a prctl be done per thread?

> 
> This looks like something other architectures may want as well.

Probably.