linux-kernel - Re: [PATCH v6 1/1] MIPS: Fix idle VS timer enqueue

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Message-ID: <Z9rjZf0ZT7iejVlA@alpha.franken.de>
Date: Wed, 19 Mar 2025 16:31:49 +0100
From: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To: Frederic Weisbecker <frederic@...nel.org>
Cc: Marco Crivellari <marco.crivellari@...e.com>,
	linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
	Anna-Maria Behnsen <anna-maria@...utronix.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Huacai Chen <chenhuacai@...nel.org>,
	"Maciej W . Rozycki" <macro@...am.me.uk>
Subject: Re: [PATCH v6 1/1] MIPS: Fix idle VS timer enqueue

On Wed, Mar 19, 2025 at 03:43:13PM +0100, Frederic Weisbecker wrote:
> > >  	.set	MIPS_ISA_ARCH_LEVEL_RAW
> > > +	/*
> > > +	 * If an interrupt lands here, between enabling interrupts above and
> > > +	 * going idle on the next instruction, we must *NOT* go idle since the
> > > +	 * interrupt could have set TIF_NEED_RESCHED or caused a timer to need
> > > +	 * resched. Fall through -- see rollback_handler below -- and have
> > > +	 * the idle loop take care of things.
> > > +	 */
> > >  	wait
> > > -	/* end of rollback region (the region size must be power of two) */
> > > +	/* End of idle interrupt region. */
> > >  1:
> > 
> > please give this label a name for example __r4k_wait_exit and do a
> > runtime check that it really has 36 bytes offset to __r4k_wait
> 
> Where would be the best place for that?
> 
> arch/mips/kernel/setup.c:setup_arch() maybe?

scratch runtime check, a compile check is what I wanted to write...

something like

.if ((__r4k_wait_exit - __r4k_wait) != 36)
.err
.endif

Thomas.

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