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Date:   Tue, 10 Nov 2020 14:42:23 +0100
From:   Frederic Weisbecker <frederic@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>,
        Michal Hocko <mhocko@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Michal Hocko <mhocko@suse.com>
Subject: Re: [RFC PATCH 1/7] static_call/x86: Add __static_call_returnl0()
Message-ID: <20201110134223.GB48886@lothringen>
References: <20201110005609.40989-1-frederic@kernel.org>
 <20201110005609.40989-2-frederic@kernel.org>
 <20201110095515.GA2594@hirez.programming.kicks-ass.net>
 <20201110101307.GO2651@hirez.programming.kicks-ass.net>
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On Tue, Nov 10, 2020 at 11:13:07AM +0100, Peter Zijlstra wrote:
> On Tue, Nov 10, 2020 at 10:55:15AM +0100, Peter Zijlstra wrote:
> > On Tue, Nov 10, 2020 at 01:56:03AM +0100, Frederic Weisbecker wrote:
> > 
> > > [fweisbec: s/disp16/data16, integrate into text_get_insn(), elaborate
> > >  comment on the resulting insn, emulate on int3 trap, provide validation,
> > >  uninline __static_call_return0() for HAVE_STATIC_CALL]
> 
> > Why did you add full emulation of this? The patch I send to you used the
> > text_poke_bp(.emulate) argument to have it emulate an actual call to the
> > out-of-line version of that function.
> > 
> > That should work fine and is a lot less code.
> 
> For reference; the below is what I send you. Actually doing the
> __static_call_return0() call while we poke the magic XOR instruction is
> much simpler.

Ok I'll get back to that. I'll just tweak a bit static_call_validate()
so that it is aware of that instruction.

Thanks.