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Date: Wed, 24 Jan 2024 19:44:20 +0100
From: Andrea Parri <parri.andrea@gmail.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu,
	paulmck@kernel.org, corbet@lwn.net, mmaas@google.com,
	hboehm@google.com, striker@us.ibm.com, charlie@rivosinc.com,
	rehn@rivosinc.com, linux-riscv@lists.infradead.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 4/4] membarrier: riscv: Provide core serializing
 command
Message-ID: <ZbFahHxi5laA6CbI@andrea>
References: <20240110145533.60234-1-parri.andrea@gmail.com>
 <20240110145533.60234-5-parri.andrea@gmail.com>
 <aabea058-0088-41bb-822a-402669f348bb@efficios.com>
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> > +# 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