From: sebastian.capella@linaro•org (Sebastian Capella)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v6 2/2] ARM hibernation / suspend-to-disk
Date: Tue, 04 Mar 2014 16:18:15 -0800 [thread overview]
Message-ID: <53166d4d.6289420a.3401.2109@mx.google.com> (raw)
In-Reply-To: <20140304111745.GB21431@e102568-lin.cambridge.arm.com>
Quoting Lorenzo Pieralisi (2014-03-04 03:17:46)
> On Tue, Mar 04, 2014 at 09:55:31AM +0000, Sebastian Capella wrote:
> > Quoting Sebastian Capella (2014-02-28 15:38:54)
> > > Quoting Lorenzo Pieralisi (2014-02-28 14:49:33)
> > > > On Fri, Feb 28, 2014 at 08:15:57PM +0000, Sebastian Capella wrote:
> > > > > >
> > > > > > This does not guarantee your stack is 8-byte aligned, that's not AAPCS
> > > > > > compliant and might buy you trouble.
> > > > > >
> > > > > > Either you align the stack or you align the pointer you are passing.
> > > > > >
> > > > > > Please have a look at kernel/process.c
> > > > >
> > > > > I've added this for now, do you see any issues?
> > > > >
> > > > > -static u8 resume_stack[PAGE_SIZE/2] __nosavedata;
> > > > > +static u64 resume_stack[PAGE_SIZE/2/sizeof(u64)] __nosavedata;
> > > > > - resume_stack + sizeof(resume_stack));
> > > > > + resume_stack + ARRAY_SIZE(resume_stack));
> > > >
> > > > I do not see why the stack depends on the PAGE_SIZE. I would be surprised
> > > > if you need more than a few bytes (given that soft_restart switches stack
> > > > again...), go through it with a debugger, it is easy to check the stack
> > > > usage and allow for some extra buffer (but half a page is not needed).
> > >
> > > I assuming this is becase the no-save region is one page anyway (we skip
> > > restoring the no-save region physical page). So maybe 1/2 is a way to
> > > leave some room for whatever else may need to be here, but in any case
> > > the 4k is used for nosave. I think you're right that it can be much less.
> >
> > Hi Lorenzo,
> >
> > Are you ok with this just being half a page? Or do you want me to try
> > to reduce the stack size? I am at Connect without my debugger, so in
> > that case it would have to wait until next week.
>
> I am ok, either you leave that as it is (that multiple division looks
> horrible but it is just nitpicking on my side) or define it as an u8 array,
> stick __attribute__((aligned(8)) to the definition (and explain why) and be
> done with it.
>
> You can add my:
>
> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm•com>
Thanks Lorenzo!
Sebastian
prev parent reply other threads:[~2014-03-05 0:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 23:57 [PATCH v6 0/2] hibernation support on ARM Sebastian Capella
2014-02-27 23:57 ` [PATCH v6 1/2] ARM: avoid tracers in soft_restart Sebastian Capella
2014-02-27 23:57 ` [PATCH v6 2/2] ARM hibernation / suspend-to-disk Sebastian Capella
2014-02-28 0:09 ` Stephen Boyd
2014-02-28 1:47 ` Russ Dill
2014-02-28 2:19 ` Stephen Boyd
2014-02-28 10:20 ` Russell King - ARM Linux
[not found] ` <20140228181731.29118.41809@capellas-linux>
2014-03-05 2:28 ` Sebastian Capella
2014-06-02 16:57 ` Sebastian Capella
2014-02-28 9:50 ` Lorenzo Pieralisi
2014-02-28 20:15 ` Sebastian Capella
2014-02-28 22:49 ` Lorenzo Pieralisi
2014-02-28 23:38 ` Sebastian Capella
2014-03-04 9:55 ` Sebastian Capella
2014-03-04 11:17 ` Lorenzo Pieralisi
2014-03-05 0:18 ` Sebastian Capella [this message]
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