[PATCH] powerpc/cell: disable ptcal in case of kdump reboot

[PATCH] powerpc/cell: disable ptcal in case of kdump reboot

[Arnd Bergmann]

The ibm,cbe-start-ptcal rtas call transfers ownership
of a memory range to the hardware in order to do
periodic memory interface recalibration.
When we do a kexec, we need to get this page back,
so we don't step on the new kernel's toes.
We used to do this correctly in case of a user triggered
kexec, but not for kdump.

This patch disables ptcal from the cell specific
machine_crash_shutdown() callback. I also needed
to fix the pseries code that tries to install its
default_machine_crash_shutdown() code independent
of what machine we're running on.

The fix has been verified by Akira Tsukamoto, the
original reporter of the problem.

Acked-by: Akira Tsukamoto <akirat@rd.scei.sony.co.jp>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/powerpc/platforms/cell/ras.c      |    6 ++++++
 arch/powerpc/platforms/cell/ras.h      |    1 +
 arch/powerpc/platforms/cell/setup.c    |    2 +-
 arch/powerpc/platforms/pseries/kexec.c |    2 +-
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/cell/ras.c b/arch/powerpc/platforms/cell/ras.c
index 655704a..21b313d 100644
--- a/arch/powerpc/platforms/cell/ras.c
+++ b/arch/powerpc/platforms/cell/ras.c
@@ -226,6 +226,12 @@ static int cbe_ptcal_notify_reboot(struct notifier_block *nb,
 	return cbe_ptcal_disable();
 }
 
+void cbe_machine_crash_shutdown(struct pt_regs *regs)
+{
+	cbe_ptcal_disable();
+	return default_machine_crash_shutdown(regs);
+}
+
 static struct notifier_block cbe_ptcal_reboot_notifier = {
 	.notifier_call = cbe_ptcal_notify_reboot
 };
diff --git a/arch/powerpc/platforms/cell/ras.h b/arch/powerpc/platforms/cell/ras.h
index eb7ee54..d1401f9 100644
--- a/arch/powerpc/platforms/cell/ras.h
+++ b/arch/powerpc/platforms/cell/ras.h
@@ -5,5 +5,6 @@ extern void cbe_system_error_exception(struct pt_regs *regs);
 extern void cbe_maintenance_exception(struct pt_regs *regs);
 extern void cbe_thermal_exception(struct pt_regs *regs);
 extern void cbe_ras_init(void);
+extern void cbe_machine_crash_shutdown(struct pt_regs *regs);
 
 #endif /* RAS_H */
diff --git a/arch/powerpc/platforms/cell/setup.c b/arch/powerpc/platforms/cell/setup.c
index ab721b5..b555030 100644
--- a/arch/powerpc/platforms/cell/setup.c
+++ b/arch/powerpc/platforms/cell/setup.c
@@ -292,6 +292,6 @@ define_machine(cell) {
 #ifdef CONFIG_KEXEC
 	.machine_kexec		= default_machine_kexec,
 	.machine_kexec_prepare	= default_machine_kexec_prepare,
-	.machine_crash_shutdown	= default_machine_crash_shutdown,
+	.machine_crash_shutdown	= cbe_machine_crash_shutdown,
 #endif
 };
diff --git a/arch/powerpc/platforms/pseries/kexec.c b/arch/powerpc/platforms/pseries/kexec.c
index e9dd5fe..53cbd53 100644
--- a/arch/powerpc/platforms/pseries/kexec.c
+++ b/arch/powerpc/platforms/pseries/kexec.c
@@ -70,4 +70,4 @@ static int __init pseries_kexec_setup(void)
 
 	return 0;
 }
-__initcall(pseries_kexec_setup);
+machine_device_initcall(pseries, pseries_kexec_setup);
-- 
1.5.4.3

please pull merge branch of cell-2.6.git

[Arnd Bergmann]

Hi Paul,

Please pull the fix I just sent from

  master.kernel.org/pub/scm/linux/kernel/git/arnd/cell-2.6.git merge

Jeremy might want to look at it as well, since he wrote the
code originally.

Thanks,

	Arnd <><

---
Arnd Bergmann <arnd@arndb.de>:
     powerpc/cell: disable ptcal in case of kdump reboot

 arch/powerpc/platforms/cell/ras.c      |    6 ++++++
 arch/powerpc/platforms/cell/ras.h      |    1 +
 arch/powerpc/platforms/cell/setup.c    |    2 +-
 arch/powerpc/platforms/pseries/kexec.c |    2 +-
 4 files changed, 9 insertions(+), 2 deletions(-)

Re: [Cbe-oss-dev] [PATCH] powerpc/cell: disable ptcal in case of kdump reboot

[Michael Ellerman]

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On Wed, 2008-06-11 at 18:28 +0200, Arnd Bergmann wrote:
> The ibm,cbe-start-ptcal rtas call transfers ownership
> of a memory range to the hardware in order to do
> periodic memory interface recalibration.
> When we do a kexec, we need to get this page back,
> so we don't step on the new kernel's toes.
> We used to do this correctly in case of a user triggered
> kexec, but not for kdump.

Used to?

> This patch disables ptcal from the cell specific
> machine_crash_shutdown() callback. 

I'd rather you used the crash_shutdown_register() infrastructure Mikey
added for EHEA - it's designed for just this sort of thing.

> I also needed to fix the pseries code that tries to install its
> default_machine_crash_shutdown() code independent
> of what machine we're running on.

That's a buglet.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: [Cbe-oss-dev] [PATCH] powerpc/cell: disable ptcal in case of kdump reboot

[Arnd Bergmann]

On Wednesday 11 June 2008, Michael Ellerman wrote:
> On Wed, 2008-06-11 at 18:28 +0200, Arnd Bergmann wrote:
> > We used to do this correctly in case of a user triggered
> > kexec, but not for kdump.
> 
> Used to?

Sorry, wrong wording. I meant without this patch, it's correct
for kexec.
 
> > This patch disables ptcal from the cell specific
> > machine_crash_shutdown() callback. 
> 
> I'd rather you used the crash_shutdown_register() infrastructure Mikey
> added for EHEA - it's designed for just this sort of thing.

Thanks for pointing this out, I wasn't aware of that call.
New patch coming up.

	Arnd <><

Re: [Cbe-oss-dev] [PATCH] powerpc/cell: disable ptcal in case of kdump reboot

[Michael Neuling]

In message <200806120939.23836.arnd@arndb.de> you wrote:
> On Wednesday 11 June 2008, Michael Ellerman wrote:
> > On Wed, 2008-06-11 at 18:28 +0200, Arnd Bergmann wrote:
> > > We used to do this correctly in case of a user triggered
> > > kexec, but not for kdump.
> > 
> > Used to?
> 
> Sorry, wrong wording. I meant without this patch, it's correct
> for kexec.
>  
> > > This patch disables ptcal from the cell specific
> > > machine_crash_shutdown() callback. 
> > 
> > I'd rather you used the crash_shutdown_register() infrastructure Mikey
> > added for EHEA - it's designed for just this sort of thing.
> 
> Thanks for pointing this out, I wasn't aware of that call.
> New patch coming up.

In theory we can register lots of call backs but currently the maximum
is set to 1 through CRASH_HANDLER_MAX.  This is to discourage people
from using this infrastructure at all.

Unless there's some crazy arse company that's going to mix a CBE with an
eHEA, we are probably ok leaving this at 1.  Right?

Mikey

Re: [Cbe-oss-dev] [PATCH] powerpc/cell: disable ptcal in case of kdump reboot

[Michael Ellerman]

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On Thu, 2008-06-12 at 18:06 +1000, Michael Neuling wrote:
> In message <200806120939.23836.arnd@arndb.de> you wrote:
> > On Wednesday 11 June 2008, Michael Ellerman wrote:
> > > On Wed, 2008-06-11 at 18:28 +0200, Arnd Bergmann wrote:
> > > > We used to do this correctly in case of a user triggered
> > > > kexec, but not for kdump.
> > > 
> > > Used to?
> > 
> > Sorry, wrong wording. I meant without this patch, it's correct
> > for kexec.
> >  
> > > > This patch disables ptcal from the cell specific
> > > > machine_crash_shutdown() callback. 
> > > 
> > > I'd rather you used the crash_shutdown_register() infrastructure Mikey
> > > added for EHEA - it's designed for just this sort of thing.
> > 
> > Thanks for pointing this out, I wasn't aware of that call.
> > New patch coming up.
> 
> In theory we can register lots of call backs but currently the maximum
> is set to 1 through CRASH_HANDLER_MAX.  This is to discourage people
> from using this infrastructure at all.

Yeah true. In this case I think it's the less horrible solution to
something that's fundamentally kdump-unfriendly.

> Unless there's some crazy arse company that's going to mix a CBE with an
> eHEA, we are probably ok leaving this at 1.  Right?

No comment *cough*. I guess I'd say just increase it to 2 on the off
chance, can't hurt much.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: [Cbe-oss-dev] [PATCH] powerpc/cell: disable ptcal in case of kdump reboot

[Michael Neuling]

In message <1213261480.8652.5.camel@localhost> you wrote:
> 
> On Thu, 2008-06-12 at 18:06 +1000, Michael Neuling wrote:
> > In message <200806120939.23836.arnd@arndb.de> you wrote:
> > > On Wednesday 11 June 2008, Michael Ellerman wrote:
> > > > On Wed, 2008-06-11 at 18:28 +0200, Arnd Bergmann wrote:
> > > > > We used to do this correctly in case of a user triggered
> > > > > kexec, but not for kdump.
> > > >=20
> > > > Used to?
> > >=20
> > > Sorry, wrong wording. I meant without this patch, it's correct
> > > for kexec.
> > > =20
> > > > > This patch disables ptcal from the cell specific
> > > > > machine_crash_shutdown() callback.=20
> > > >=20
> > > > I'd rather you used the crash_shutdown_register() infrastructure Mike=
> y
> > > > added for EHEA - it's designed for just this sort of thing.
> > >=20
> > > Thanks for pointing this out, I wasn't aware of that call.
> > > New patch coming up.
> >=20
> > In theory we can register lots of call backs but currently the maximum
> > is set to 1 through CRASH_HANDLER_MAX.  This is to discourage people
> > from using this infrastructure at all.
> 
> Yeah true. In this case I think it's the less horrible solution to
> something that's fundamentally kdump-unfriendly.
> 
> > Unless there's some crazy arse company that's going to mix a CBE with an
> > eHEA, we are probably ok leaving this at 1.  Right?
> 
> No comment *cough*. I guess I'd say just increase it to 2 on the off
> chance, can't hurt much.

Ok.. but this one really really is the last one!! :-)

Mikey