[PATCH] riscv: keep interrupts disabled for BREAKPOINT exception
Maciej W. Rozycki
macro at orcam.me.uk
Thu Apr 8 23:45:13 BST 2021
On Fri, 9 Apr 2021, Masami Hiramatsu wrote:
> > > Is this approach guaranteed to keep interrupt handling latency low enough
> > > for the system not to be negatively affected, e.g. for the purpose of NTP
> > > timekeeping?
> > IMHO, interrupt latency can't be ensured if kprobes is triggered.
> Indeed. The latency depends on what the kprobe user handler does. Of course
> it must be as minimal as possible... On x86, it is less than a few microseconds.
> Thus it may be a jitter on hard realtime system, but not a big issue on
> usual system like NTP timekeeping.
Ack. Assuming that the breakpoint exception will only disable interrupts
if kprobes are in use it seems reasonable to me.
Thanks for double-checking.
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