* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
@ 2011-12-05 21:22 Linus Walleij
2011-12-05 21:57 ` Rob Herring
2011-12-06 10:30 ` Linus Walleij
0 siblings, 2 replies; 8+ messages in thread
From: Linus Walleij @ 2011-12-05 21:22 UTC (permalink / raw)
To: linux-arm-kernel
Hi Nico,
now I'm lost, I discussed by boot problems on ARM PB1176
with Marc and after some investigation I found this strange thing on
the lastest rc:s since -rc1:
In arch/arm/Kconfig ARM_PATCH_PHYS_VIRT is forcibly
disabled like so:
depends on !ARCH_REALVIEW || !SPARSEMEM
However if I just configure it for the realview_defconfig:
mkdir foo
make -f Makefile ARCH=arm CROSS_COMPILE=arm-none-eabi-
KBUILD_OUTPUT=foo realview_defconfig
It strangely selects this anyway, because now foo/.config has:
CONFIG_ARM_PATCH_PHYS_VIRT=y
Kconfig is a djungle to me, but I simply cannot find out
what is setting this anyway. The problem is not there on
v3.1, it does not get selected.
Any hints?
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 8+ messages in thread
* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
2011-12-05 21:22 realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me Linus Walleij
@ 2011-12-05 21:57 ` Rob Herring
2011-12-05 22:08 ` Nicolas Pitre
2011-12-06 10:30 ` Linus Walleij
1 sibling, 1 reply; 8+ messages in thread
From: Rob Herring @ 2011-12-05 21:57 UTC (permalink / raw)
To: linux-arm-kernel
On 12/05/2011 03:22 PM, Linus Walleij wrote:
> Hi Nico,
>
> now I'm lost, I discussed by boot problems on ARM PB1176
> with Marc and after some investigation I found this strange thing on
> the lastest rc:s since -rc1:
>
> In arch/arm/Kconfig ARM_PATCH_PHYS_VIRT is forcibly
> disabled like so:
>
> depends on !ARCH_REALVIEW || !SPARSEMEM
should be !ARCH_REALVIEW && !SPARSEMEM ?
Rob
>
> However if I just configure it for the realview_defconfig:
>
> mkdir foo
> make -f Makefile ARCH=arm CROSS_COMPILE=arm-none-eabi-
> KBUILD_OUTPUT=foo realview_defconfig
>
> It strangely selects this anyway, because now foo/.config has:
> CONFIG_ARM_PATCH_PHYS_VIRT=y
>
> Kconfig is a djungle to me, but I simply cannot find out
> what is setting this anyway. The problem is not there on
> v3.1, it does not get selected.
>
> Any hints?
>
> Yours,
> Linus Walleij
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 8+ messages in thread
* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
2011-12-05 21:57 ` Rob Herring
@ 2011-12-05 22:08 ` Nicolas Pitre
2011-12-05 23:36 ` Russell King - ARM Linux
0 siblings, 1 reply; 8+ messages in thread
From: Nicolas Pitre @ 2011-12-05 22:08 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, 5 Dec 2011, Rob Herring wrote:
> On 12/05/2011 03:22 PM, Linus Walleij wrote:
> > Hi Nico,
> >
> > now I'm lost, I discussed by boot problems on ARM PB1176
> > with Marc and after some investigation I found this strange thing on
> > the lastest rc:s since -rc1:
> >
> > In arch/arm/Kconfig ARM_PATCH_PHYS_VIRT is forcibly
> > disabled like so:
> >
> > depends on !ARCH_REALVIEW || !SPARSEMEM
>
> should be !ARCH_REALVIEW && !SPARSEMEM ?
Indeed.
Nicolas
^ permalink raw reply [flat|nested] 8+ messages in thread
* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
2011-12-05 22:08 ` Nicolas Pitre
@ 2011-12-05 23:36 ` Russell King - ARM Linux
2011-12-06 0:37 ` Nicolas Pitre
2011-12-06 8:29 ` Colin Tuckley
0 siblings, 2 replies; 8+ messages in thread
From: Russell King - ARM Linux @ 2011-12-05 23:36 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Dec 05, 2011 at 05:08:12PM -0500, Nicolas Pitre wrote:
> On Mon, 5 Dec 2011, Rob Herring wrote:
>
> > On 12/05/2011 03:22 PM, Linus Walleij wrote:
> > > Hi Nico,
> > >
> > > now I'm lost, I discussed by boot problems on ARM PB1176
> > > with Marc and after some investigation I found this strange thing on
> > > the lastest rc:s since -rc1:
> > >
> > > In arch/arm/Kconfig ARM_PATCH_PHYS_VIRT is forcibly
> > > disabled like so:
> > >
> > > depends on !ARCH_REALVIEW || !SPARSEMEM
> >
> > should be !ARCH_REALVIEW && !SPARSEMEM ?
>
> Indeed.
No, it's correct. None of you are understanding the logic.
If you don't understand it, draw up a truth table:
ARCH_REALVIEW SPARSEMEM result
n n y
n y y
y n y
y y n
And this clearly shows that if we have realview _and_ sparsemem enabled,
then we don't want P2V patching in place. The reason for this is quite
simple - here's Realview's memory.h:
#ifdef CONFIG_SPARSEMEM
#define __phys_to_virt(phys) \
((phys) >= 0x80000000 ? (phys) - 0x80000000 + PAGE_OFFSET2 : \
(phys) >= 0x20000000 ? (phys) - 0x20000000 + PAGE_OFFSET1 : \
(phys) + PAGE_OFFSET)
#define __virt_to_phys(virt) \
((virt) >= PAGE_OFFSET2 ? (virt) - PAGE_OFFSET2 + 0x80000000 : \
(virt) >= PAGE_OFFSET1 ? (virt) - PAGE_OFFSET1 + 0x20000000 : \
(virt) - PAGE_OFFSET)
#endif /* CONFIG_SPARSEMEM */
Or to put it another way: on Realview if sparsemem is enabled, then we
are incompatible with P2V (due to the non-linear translation) so we have
a dependency there to disable it.
^ permalink raw reply [flat|nested] 8+ messages in thread* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
2011-12-05 23:36 ` Russell King - ARM Linux
@ 2011-12-06 0:37 ` Nicolas Pitre
2011-12-06 0:46 ` Russell King - ARM Linux
2011-12-06 8:29 ` Colin Tuckley
1 sibling, 1 reply; 8+ messages in thread
From: Nicolas Pitre @ 2011-12-06 0:37 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, 5 Dec 2011, Russell King - ARM Linux wrote:
> On Mon, Dec 05, 2011 at 05:08:12PM -0500, Nicolas Pitre wrote:
> > On Mon, 5 Dec 2011, Rob Herring wrote:
> >
> > > On 12/05/2011 03:22 PM, Linus Walleij wrote:
> > > > Hi Nico,
> > > >
> > > > now I'm lost, I discussed by boot problems on ARM PB1176
> > > > with Marc and after some investigation I found this strange thing on
> > > > the lastest rc:s since -rc1:
> > > >
> > > > In arch/arm/Kconfig ARM_PATCH_PHYS_VIRT is forcibly
> > > > disabled like so:
> > > >
> > > > depends on !ARCH_REALVIEW || !SPARSEMEM
> > >
> > > should be !ARCH_REALVIEW && !SPARSEMEM ?
> >
> > Indeed.
>
> No, it's correct. None of you are understanding the logic.
>
> If you don't understand it, draw up a truth table:
>
> ARCH_REALVIEW SPARSEMEM result
> n n y
> n y y
> y n y
> y y n
>
> And this clearly shows that if we have realview _and_ sparsemem enabled,
> then we don't want P2V patching in place.
I didn't look closely at Realview. However the usefulness of P2V
patching when sparsemem is used is somewhat questionable I would say.
Nicolas
^ permalink raw reply [flat|nested] 8+ messages in thread
* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
2011-12-06 0:37 ` Nicolas Pitre
@ 2011-12-06 0:46 ` Russell King - ARM Linux
0 siblings, 0 replies; 8+ messages in thread
From: Russell King - ARM Linux @ 2011-12-06 0:46 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Dec 05, 2011 at 07:37:26PM -0500, Nicolas Pitre wrote:
> On Mon, 5 Dec 2011, Russell King - ARM Linux wrote:
>
> > On Mon, Dec 05, 2011 at 05:08:12PM -0500, Nicolas Pitre wrote:
> > > On Mon, 5 Dec 2011, Rob Herring wrote:
> > >
> > > > On 12/05/2011 03:22 PM, Linus Walleij wrote:
> > > > > Hi Nico,
> > > > >
> > > > > now I'm lost, I discussed by boot problems on ARM PB1176
> > > > > with Marc and after some investigation I found this strange thing on
> > > > > the lastest rc:s since -rc1:
> > > > >
> > > > > In arch/arm/Kconfig ARM_PATCH_PHYS_VIRT is forcibly
> > > > > disabled like so:
> > > > >
> > > > > depends on !ARCH_REALVIEW || !SPARSEMEM
> > > >
> > > > should be !ARCH_REALVIEW && !SPARSEMEM ?
> > >
> > > Indeed.
> >
> > No, it's correct. None of you are understanding the logic.
> >
> > If you don't understand it, draw up a truth table:
> >
> > ARCH_REALVIEW SPARSEMEM result
> > n n y
> > n y y
> > y n y
> > y y n
> >
> > And this clearly shows that if we have realview _and_ sparsemem enabled,
> > then we don't want P2V patching in place.
>
> I didn't look closely at Realview. However the usefulness of P2V
> patching when sparsemem is used is somewhat questionable I would say.
No it isn't.
Provided there's a linear v:p mapping, P2V can be used. Only when
there's a non-linear mapping does P2V fail. That's got nothing to do
with sparsemem, as you can be using sparsemem and still have a linear
v:p mapping (and several platforms do.)
^ permalink raw reply [flat|nested] 8+ messages in thread
* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
2011-12-05 23:36 ` Russell King - ARM Linux
2011-12-06 0:37 ` Nicolas Pitre
@ 2011-12-06 8:29 ` Colin Tuckley
1 sibling, 0 replies; 8+ messages in thread
From: Colin Tuckley @ 2011-12-06 8:29 UTC (permalink / raw)
To: linux-arm-kernel
> -----Original Message-----
> depends on !ARCH_REALVIEW || !SPARSEMEM
> No, it's correct. None of you are understanding the logic.
> And this clearly shows that if we have realview _and_ sparsemem
> enabled,
> then we don't want P2V patching in place.
In which case wouldn't it be clearer if it was written as:
depends on !(ARCH_REALVIEW && SPARSEMEM)
Colin
^ permalink raw reply [flat|nested] 8+ messages in thread
* realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me
2011-12-05 21:22 realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me Linus Walleij
2011-12-05 21:57 ` Rob Herring
@ 2011-12-06 10:30 ` Linus Walleij
1 sibling, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2011-12-06 10:30 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Dec 5, 2011 at 10:22 PM, Linus Walleij <linus.walleij@linaro.org> wrote:
> In arch/arm/Kconfig ARM_PATCH_PHYS_VIRT is forcibly
> disabled like so:
>
> depends on !ARCH_REALVIEW || !SPARSEMEM
OK so I understand from the discussion that P2V should work
perfectly well with the RealView as long as you're not using
sparsemem. And now something has changed in v3.2-rc1
kernel so it gets default-selected as opposed to being
disabled in v3.1.
So my boot problem is likely due to something else...
I'll keep looking.
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2011-12-06 10:30 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
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2011-12-05 21:22 realview compulsory enables CONFIG_ARM_PATCH_PHYS_VIRT on me Linus Walleij
2011-12-05 21:57 ` Rob Herring
2011-12-05 22:08 ` Nicolas Pitre
2011-12-05 23:36 ` Russell King - ARM Linux
2011-12-06 0:37 ` Nicolas Pitre
2011-12-06 0:46 ` Russell King - ARM Linux
2011-12-06 8:29 ` Colin Tuckley
2011-12-06 10:30 ` Linus Walleij
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