From: Michael Neuling <mikey@neuling.org>
To: Kumar Gala <galak@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>,
miltonm@bga.com, linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] powerpc: add denormalisation exception handling for POWER6/7
Date: Wed, 13 Jul 2011 15:30:21 +1000 [thread overview]
Message-ID: <15559.1310535021@neuling.org> (raw)
In-Reply-To: <5E6FBB75-BE97-4D97-AEA2-EC8EAF1E0ECF@kernel.crashing.org>
In message <5E6FBB75-BE97-4D97-AEA2-EC8EAF1E0ECF@kernel.crashing.org> you wrote
:
>
> On Jul 11, 2011, at 12:52 AM, Michael Neuling wrote:
>
> > On POWER6 and POWER7 if the input operand to an instruction is a
> > denormalised single precision binary floating we can take a
> > denormalisation exception where it's expected that the hypervisor =
> (HV=3D1)
> > will fix up the inputs before the instruction is run.
> >=20
> > This adds code to handle this denormalisation exception for POWER6 and
> > POWER7.
> >=20
> > It also add a CONFIG_PPC_DENORMALISATION option and sets it in
> > pseries/ppc64_defconfig.=20
> >=20
> > This is useful on bare metal systems only. Based on patch from Milton
> > Miller.
> >=20
> > Signed-off-by: Michael Neuling <mikey@neuling.org>
> >=20
> > ---
> > arch/powerpc/Kconfig | 7 +
> > arch/powerpc/configs/ppc64_defconfig | 1=20
> > arch/powerpc/configs/pseries_defconfig | 1=20
> > arch/powerpc/include/asm/ppc-opcode.h | 2=20
> > arch/powerpc/include/asm/reg.h | 1=20
> > arch/powerpc/kernel/exceptions-64s.S | 125 =
> +++++++++++++++++++++++++++++++++
> > 6 files changed, 137 insertions(+)
> >=20
> > Index: linux-ozlabs/arch/powerpc/Kconfig
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > --- linux-ozlabs.orig/arch/powerpc/Kconfig
> > +++ linux-ozlabs/arch/powerpc/Kconfig
> > @@ -556,6 +556,13 @@ config SCHED_SMT
> > when dealing with POWER5 cpus at a cost of slightly increased
> > overhead in some places. If unsure say N here.
> >=20
> > +config PPC_DENORMALISATION
> > + bool "PowerPC denormalisation exception handling"
>
> Should this at least depend on PPC_BOOK3S_64 ?
Yep, thanks!
Mikey
next prev parent reply other threads:[~2011-07-13 5:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-11 5:52 [PATCH] powerpc: add denormalisation exception handling for POWER6/7 Michael Neuling
2011-07-12 3:51 ` Kumar Gala
2011-07-12 4:12 ` Benjamin Herrenschmidt
2011-07-13 5:27 ` Kumar Gala
2011-07-13 5:30 ` Michael Neuling [this message]
2012-09-10 6:54 ` Michael Neuling
2012-09-10 8:13 ` Michael Ellerman
2012-09-10 10:33 ` Michael Neuling
2012-09-10 10:35 ` Michael Neuling
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