Mailing List Archive: Linux: Kernel

[PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set

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mel at csn

Nov 17, 2009, 4:07 AM

Post #1 of 8 (280 views)
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[PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set

KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
it's not set, there are numerous small build errors. This is a small series
of patches to allow CONFIG_XICS to be unset in the config.

XICS appears to be some sort of interrupt controller but I'm not sure how
common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
universally requires CONFIG_XICS, the better path might be to force it to
be set.

Testing was building with make oldconfig a configuration from 2.6.31 on
a PPC970.
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michael at ellerman

Nov 17, 2009, 4:39 AM

Post #2 of 8 (263 views)
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Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set [In reply to]

On Tue, 2009-11-17 at 12:07 +0000, Mel Gorman wrote:
> KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
> it's not set, there are numerous small build errors. This is a small series
> of patches to allow CONFIG_XICS to be unset in the config.
>
> XICS appears to be some sort of interrupt controller but I'm not sure how
> common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
> universally requires CONFIG_XICS, the better path might be to force it to
> be set.

It is indeed 'some sort of interrupt controller' :)

All the virtualised PSERIES systems have, or appear to have, a XICS. So
it's pretty common.

I think the only time you see an MPIC is on older machines, and even
then maybe only if you're running bare metal.

So it is pretty much required for a PSERIES kernel, but perhaps there
are cases where the BML guys want to be able to turn it off.

cheers

Attachments:

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michael at ellerman

Nov 17, 2009, 4:52 AM

Post #3 of 8 (263 views)
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Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set [In reply to]

On Tue, 2009-11-17 at 23:39 +1100, Michael Ellerman wrote:
> On Tue, 2009-11-17 at 12:07 +0000, Mel Gorman wrote:
> > KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
> > it's not set, there are numerous small build errors. This is a small series
> > of patches to allow CONFIG_XICS to be unset in the config.
> >
> > XICS appears to be some sort of interrupt controller but I'm not sure how
> > common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
> > universally requires CONFIG_XICS, the better path might be to force it to
> > be set.
>
> It is indeed 'some sort of interrupt controller' :)
>
> All the virtualised PSERIES systems have, or appear to have, a XICS. So
> it's pretty common.
>
> I think the only time you see an MPIC is on older machines, and even
> then maybe only if you're running bare metal.
>
> So it is pretty much required for a PSERIES kernel, but perhaps there
> are cases where the BML guys want to be able to turn it off.

In fact this series makes me wonder whether we can drop support for a
single kernel image with pseries XICS & MPIC support.

If we could drop that requirement we could have a single set of names,
ie. API, for the irq routines and build either the XICS or MPIC
versions.

That would avoid all the code that needs a setup_foo_xics() and
setup_foo_mpic() - it'd just be setup_foo(), implemented by either the
XICS or MPIC code.

cheers

Attachments:

signature.asc (0.19 KB)

mel at csn

Nov 17, 2009, 5:25 AM

Post #4 of 8 (263 views)
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Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set [In reply to]

On Tue, Nov 17, 2009 at 11:39:04PM +1100, Michael Ellerman wrote:
> On Tue, 2009-11-17 at 12:07 +0000, Mel Gorman wrote:
> > KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
> > it's not set, there are numerous small build errors. This is a small series
> > of patches to allow CONFIG_XICS to be unset in the config.
> >
> > XICS appears to be some sort of interrupt controller but I'm not sure how
> > common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
> > universally requires CONFIG_XICS, the better path might be to force it to
> > be set.
>
> It is indeed 'some sort of interrupt controller' :)
>
> All the virtualised PSERIES systems have, or appear to have, a XICS. So
> it's pretty common.
>
> I think the only time you see an MPIC is on older machines, and even
> then maybe only if you're running bare metal.
>
> So it is pretty much required for a PSERIES kernel, but perhaps there
> are cases where the BML guys want to be able to turn it off.
>

Do you want to take ownership of the series as I'm a bit unclear on how
and when XICS should be used? If not, I don't mind fixing the series up
as you suggested but I wouldn't be in the best position to determine if
the final result is sensible or not.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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benh at kernel

Nov 17, 2009, 10:00 PM

Post #5 of 8 (250 views)
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Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set [In reply to]

On Tue, 2009-11-17 at 23:52 +1100, Michael Ellerman wrote:
>
> In fact this series makes me wonder whether we can drop support for a
> single kernel image with pseries XICS & MPIC support.

Nope. Not happening. We should just hide CONFIG_XICS just like
CONFIG_MPIC, it should be select'ed by the platform (which today is only
pseries but that might change).

> If we could drop that requirement we could have a single set of names,
> ie. API, for the irq routines and build either the XICS or MPIC
> versions.

And so we would have the ability to build a kernel that supports in a
single binary every platform, as is the case today, ie, pseries,
powermac, pa6t, cell, etc... _BUT_ for pseries support, we would have to
choose at compile time whether to support old or new machines ? Sounds
backward to me :-)

> That would avoid all the code that needs a setup_foo_xics() and
> setup_foo_mpic() - it'd just be setup_foo(), implemented by either the
> XICS or MPIC code.

And that would save us what ? one page on a pSeries machine ? yeah !

Cheers,
Ben.

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benh at kernel

Nov 17, 2009, 10:05 PM

Post #6 of 8 (254 views)
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Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set [In reply to]

On Tue, 2009-11-17 at 12:07 +0000, Mel Gorman wrote:
> KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
> it's not set, there are numerous small build errors. This is a small series
> of patches to allow CONFIG_XICS to be unset in the config.
>
> XICS appears to be some sort of interrupt controller but I'm not sure how
> common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
> universally requires CONFIG_XICS, the better path might be to force it to
> be set.
>
> Testing was building with make oldconfig a configuration from 2.6.31 on
> a PPC970.

CONFIG_XICS should be made invisible and selected by PSERIES.

Cheers,
Ben.

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mel at csn

Nov 18, 2009, 9:05 AM

Post #7 of 8 (248 views)
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Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set [In reply to]

On Wed, Nov 18, 2009 at 05:05:32PM +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2009-11-17 at 12:07 +0000, Mel Gorman wrote:
> > KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
> > it's not set, there are numerous small build errors. This is a small series
> > of patches to allow CONFIG_XICS to be unset in the config.
> >
> > XICS appears to be some sort of interrupt controller but I'm not sure how
> > common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
> > universally requires CONFIG_XICS, the better path might be to force it to
> > be set.
> >
> > Testing was building with make oldconfig a configuration from 2.6.31 on
> > a PPC970.
>
> CONFIG_XICS should be made invisible and selected by PSERIES.
>

Like so?

==== CUT HERE ====

powerpc: Add Kconfig dependency on PCI_MSI for XICS and select for PSERIES

It's possible to set CONFIG_XICS without CONFIG_PCI_MSI. When that
happens, the kernel fails to build with

arch/powerpc/platforms/built-in.o: In function `.xics_startup':
xics.c:(.text+0x12f60): undefined reference to `.unmask_msi_irq'
make: *** [.tmp_vmlinux1] Error 1

Furthermore, as noted by Benjamin Herrenschmidt, "CONFIG_XICS should be
made invisible and selected by PSERIES."

This patch adds the dependency in KConfig for XICS on PCI_MSI. When
PSERIES support is being configured, both options are silently selected.

Signed-off-by: Mel Gorman <mel [at] csn>
---
arch/powerpc/platforms/Kconfig | 4 ++--
arch/powerpc/platforms/pseries/Kconfig | 2 ++
2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 04a8061..a82c470 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -52,9 +52,9 @@ config PPC_UDBG_BEAT
default n

config XICS
- depends on PPC_PSERIES
+ depends on PCI_MSI
bool
- default y
+ default n

config IPIC
bool
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index f0e6f28..81c2289 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -5,6 +5,8 @@ config PPC_PSERIES
select PPC_I8259
select PPC_RTAS
select RTAS_ERROR_LOGGING
+ select PCI_MSI
+ select XICS
select PPC_UDBG_16550
select PPC_NATIVE
select PPC_PCI_CHOICE if EMBEDDED
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benh at kernel

Nov 26, 2009, 6:40 PM

Post #8 of 8 (218 views)
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Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set [In reply to]

On Wed, 2009-11-18 at 17:05 +0000, Mel Gorman wrote:

>
> diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
> index 04a8061..a82c470 100644
> --- a/arch/powerpc/platforms/Kconfig
> +++ b/arch/powerpc/platforms/Kconfig
> @@ -52,9 +52,9 @@ config PPC_UDBG_BEAT
> default n
>
> config XICS
> - depends on PPC_PSERIES
> + depends on PCI_MSI
> bool
> - default y
> + default n

Why the above ? XICS only exist on PSERIES and select bypass depends in
nasty ways anyways.

> config IPIC
> bool
> diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
> index f0e6f28..81c2289 100644
> --- a/arch/powerpc/platforms/pseries/Kconfig
> +++ b/arch/powerpc/platforms/pseries/Kconfig
> @@ -5,6 +5,8 @@ config PPC_PSERIES
> select PPC_I8259
> select PPC_RTAS
> select RTAS_ERROR_LOGGING
> + select PCI_MSI
> + select XICS
> select PPC_UDBG_16550
> select PPC_NATIVE
> select PPC_PCI_CHOICE if EMBEDDED

The above bits look plenty enough. Can you also stick it next to the
MPIC one ?

Cheers,
Ben.

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