[PATCH] [AArch64] support -mfentry feature for arm64
Andrew Haley
aph@redhat.com
Tue Apr 19 15:02:00 GMT 2016
On 04/19/2016 03:37 PM, Pedro Alves wrote:
> On 04/19/2016 02:25 PM, Andrew Haley wrote:
>> On 04/19/2016 02:19 PM, Michael Matz wrote:
>>
>>> Well, yeah, that's traditional insn caches on multiple cores. From
>>> user space you need kernel help for this, doing interprocess
>>> interrupts to flush all such buffers on all cores (or at least those
>>> potentially fetching stuff in the patched region, if such
>>> granularity is possible). An implementation providing such is
>>> non-broken :)
>>
>> Sure. If you know of any such facility in Linux userspace, please let
>> me know. :-)
>
> Sounds like a job for the sys_membarrier system call:
>
> https://lkml.org/lkml/2015/3/18/531
> https://lwn.net/Articles/369567/
>
> I think it's available in Linux 4.3+.
So it is, thanks. I'm guessing that might be good enough for full
instruction synchronization barriers, but from looking at the kernel
source I can't really tell.
Andrew.
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