From: Balbir Singh <bsingharora@gmail.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>,
linuxppc-dev@lists.ozlabs.org, benh@kernel.crashing.org,
mpe@ellerman.id.au, paulus@samba.org, svaidy@linux.vnet.ibm.com
Subject: Re: [PATCH] Make system_reset_pSeries relocatable
Date: Wed, 27 Jul 2016 23:57:28 +1000 [thread overview]
Message-ID: <20160727135728.GC3720@350D> (raw)
In-Reply-To: <20160727215003.16b9feaf@roar.ozlabs.ibm.com>
On Wed, Jul 27, 2016 at 09:50:03PM +1000, Nicholas Piggin wrote:
> On Wed, 27 Jul 2016 17:32:06 +1000
> Balbir Singh <bsingharora@gmail.com> wrote:
>
> > +#ifndef CONFIG_RELOCATABLE
> > + b power7_wakeup_common
> > +#else
> > + /*
> > + * We can't just use a direct branch to power7_wakeup_common
> > + * because the distance from here to there depends on where
> > + * the kernel ends up being put.
> > + */
> > + mfctr r11
> > + ld r10, PACAKBASE(r13)
> > + LOAD_HANDLER(r10, power7_wakeup_common)
> > + mtctr r10
> > + bctr
> > #endif
>
> So r10 and r11 are safe to use (as well as existing registers
> being used without saving) because we are returning via the nap
> functions that caller will expect te trash volatile registers,
> yes?
>
r10, r11 are volatile as per the ABI, so yes.
> In that caie I can't see a problem with this.
>
Thanks for the review
Balbir
prev parent reply other threads:[~2016-07-27 13:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-27 7:32 [PATCH] Make system_reset_pSeries relocatable Balbir Singh
2016-07-27 9:53 ` Benjamin Herrenschmidt
2016-07-27 10:01 ` Balbir Singh
2016-07-27 11:51 ` Nicholas Piggin
2016-07-27 10:12 ` kbuild test robot
2016-07-27 11:34 ` Balbir Singh
2016-07-27 11:50 ` Nicholas Piggin
2016-07-27 13:57 ` Balbir Singh [this message]
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