[PATCH v3 4/4] membarrier: riscv: Provide core serializing command

Andrea Parri parri.andrea at gmail.com
Wed Jan 24 10:44:20 PST 2024


> > +# riscv uses xRET as return from interrupt and to return to user-space.
> > +#
> > +# Given that xRET is not core serializing, we rely on FENCE.I for providing
> > +# core serialization:
> > +#
> > +#  - by calling sync_core_before_usermode() on return from interrupt (cf.
> > +#    ipi_sync_core()),
> > +#
> > +#  - via switch_mm() and sync_core_before_usermode() (respectively, for
> > +#    uthread->uthread and kthread->uthread transitions) to go back to
> > +#    user-space.
> 
> I don't quite get the meaning of the sentence above. There seems to be a
> missing marker before "to go back".

Let's see.  Without the round brackets, the last part becomes:

  - via switch_mm() and sync_core_before_usermode() to go back to
    user-space.

This is indeed what I meant to say.  What am I missing?

  Andrea



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