powerpc: Make PPC_64K_PAGES depend on only 44x or PPC_BOOK3S_64

Message ID 20190208123416.1051-1-mpe@ellerman.id.au
State New
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  • powerpc: Make PPC_64K_PAGES depend on only 44x or PPC_BOOK3S_64
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Commit Message

Michael Ellerman Feb. 8, 2019, 12:34 p.m.
In commit 7820856a4fcd ("powerpc/mm/book3e/64: Remove unsupported
64Kpage size from 64bit booke") we dropped the 64K page size support
from the 64-bit nohash (Book3E) code.

But we didn't update the dependencies of the PPC_64K_PAGES option,
meaning a randconfig can still trigger this code and cause a build
breakage, eg:
  arch/powerpc/include/asm/nohash/64/pgtable.h:14:2: error: #error "Page size not supported"
  arch/powerpc/include/asm/nohash/mmu-book3e.h:275:2: error: #error Unsupported page size

So remove PPC_BOOK3E_64 from the dependencies. This also means we
don't need to worry about PPC_FSL_BOOK3E, because that was just trying
to prevent the PPC_BOOK3E_64=y && PPC_FSL_BOOK3E=y case.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Christophe Leroy Feb. 8, 2019, 1:01 p.m. | #1
On 02/08/2019 12:34 PM, Michael Ellerman wrote:
> In commit 7820856a4fcd ("powerpc/mm/book3e/64: Remove unsupported
> 64Kpage size from 64bit booke") we dropped the 64K page size support
> from the 64-bit nohash (Book3E) code.
> 
> But we didn't update the dependencies of the PPC_64K_PAGES option,
> meaning a randconfig can still trigger this code and cause a build
> breakage, eg:
>    arch/powerpc/include/asm/nohash/64/pgtable.h:14:2: error: #error "Page size not supported"
>    arch/powerpc/include/asm/nohash/mmu-book3e.h:275:2: error: #error Unsupported page size
> 
> So remove PPC_BOOK3E_64 from the dependencies. This also means we
> don't need to worry about PPC_FSL_BOOK3E, because that was just trying
> to prevent the PPC_BOOK3E_64=y && PPC_FSL_BOOK3E=y case.

Does it means some cleanup could be done, for instance:

arch/powerpc/include/asm/nohash/64/pgalloc.h:#ifndef CONFIG_PPC_64K_PAGES
arch/powerpc/include/asm/nohash/64/pgalloc.h:#endif /* 
CONFIG_PPC_64K_PAGES */
arch/powerpc/include/asm/nohash/64/pgtable.h:#ifdef CONFIG_PPC_64K_PAGES
arch/powerpc/include/asm/nohash/64/slice.h:#ifdef CONFIG_PPC_64K_PAGES
arch/powerpc/include/asm/nohash/64/slice.h:#else /* CONFIG_PPC_64K_PAGES */
arch/powerpc/include/asm/nohash/64/slice.h:#endif /* 
!CONFIG_PPC_64K_PAGES */
arch/powerpc/include/asm/nohash/pte-book3e.h:#ifdef CONFIG_PPC_64K_PAGES

arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES


Christophe

> 
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
>   arch/powerpc/Kconfig | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 3f237ffa0649..7a16b8a7b54b 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -694,7 +694,7 @@ config PPC_16K_PAGES
>   
>   config PPC_64K_PAGES
>   	bool "64k page size"
> -	depends on !PPC_FSL_BOOK3E && (44x || PPC_BOOK3S_64 || PPC_BOOK3E_64)
> +	depends on 44x || PPC_BOOK3S_64
>   	select HAVE_ARCH_SOFT_DIRTY if PPC_BOOK3S_64
>   
>   config PPC_256K_PAGES
>
Scott Wood Feb. 9, 2019, 7:18 p.m. | #2
On Fri, 2019-02-08 at 13:01 +0000, Christophe Leroy wrote:
> 
> On 02/08/2019 12:34 PM, Michael Ellerman wrote:
> > In commit 7820856a4fcd ("powerpc/mm/book3e/64: Remove unsupported
> > 64Kpage size from 64bit booke") we dropped the 64K page size support
> > from the 64-bit nohash (Book3E) code.
> > 
> > But we didn't update the dependencies of the PPC_64K_PAGES option,
> > meaning a randconfig can still trigger this code and cause a build
> > breakage, eg:
> >    arch/powerpc/include/asm/nohash/64/pgtable.h:14:2: error: #error "Page
> > size not supported"
> >    arch/powerpc/include/asm/nohash/mmu-book3e.h:275:2: error: #error
> > Unsupported page size
> > 
> > So remove PPC_BOOK3E_64 from the dependencies. This also means we
> > don't need to worry about PPC_FSL_BOOK3E, because that was just trying
> > to prevent the PPC_BOOK3E_64=y && PPC_FSL_BOOK3E=y case.
> 
> Does it means some cleanup could be done, for instance:
> 
> arch/powerpc/include/asm/nohash/64/pgalloc.h:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/include/asm/nohash/64/pgalloc.h:#endif /* 
> CONFIG_PPC_64K_PAGES */
> arch/powerpc/include/asm/nohash/64/pgtable.h:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/include/asm/nohash/64/slice.h:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/include/asm/nohash/64/slice.h:#else /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/include/asm/nohash/64/slice.h:#endif /* 
> !CONFIG_PPC_64K_PAGES */
> arch/powerpc/include/asm/nohash/pte-book3e.h:#ifdef CONFIG_PPC_64K_PAGES
> 
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES

More generally, if fsl is the only supported book3e platform and that's not
expected to change, everything in tlb_low_64e.S except the bolted and e6500
variants could go away.

-Scott
Michael Ellerman Feb. 19, 2019, 2:14 p.m. | #3
Christophe Leroy <christophe.leroy@c-s.fr> writes:

> On 02/08/2019 12:34 PM, Michael Ellerman wrote:
>> In commit 7820856a4fcd ("powerpc/mm/book3e/64: Remove unsupported
>> 64Kpage size from 64bit booke") we dropped the 64K page size support
>> from the 64-bit nohash (Book3E) code.
>> 
>> But we didn't update the dependencies of the PPC_64K_PAGES option,
>> meaning a randconfig can still trigger this code and cause a build
>> breakage, eg:
>>    arch/powerpc/include/asm/nohash/64/pgtable.h:14:2: error: #error "Page size not supported"
>>    arch/powerpc/include/asm/nohash/mmu-book3e.h:275:2: error: #error Unsupported page size
>> 
>> So remove PPC_BOOK3E_64 from the dependencies. This also means we
>> don't need to worry about PPC_FSL_BOOK3E, because that was just trying
>> to prevent the PPC_BOOK3E_64=y && PPC_FSL_BOOK3E=y case.
>
> Does it means some cleanup could be done, for instance:
>
> arch/powerpc/include/asm/nohash/64/pgalloc.h:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/include/asm/nohash/64/pgalloc.h:#endif /* 
> CONFIG_PPC_64K_PAGES */
> arch/powerpc/include/asm/nohash/64/pgtable.h:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/include/asm/nohash/64/slice.h:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/include/asm/nohash/64/slice.h:#else /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/include/asm/nohash/64/slice.h:#endif /* 
> !CONFIG_PPC_64K_PAGES */
> arch/powerpc/include/asm/nohash/pte-book3e.h:#ifdef CONFIG_PPC_64K_PAGES
>
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */
> arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES
> arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES

Probably.

Some of the FSL chips do support 64K pages at least according to some
datasheets. I don't know what would be required to get it working, or if
it even works in practice.

So it would be nice to get 64K working on those chips, but probably no
one has time or motivation to do it. In which case yeah all that code
should be removed.

cheers

Patch

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3f237ffa0649..7a16b8a7b54b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -694,7 +694,7 @@  config PPC_16K_PAGES
 
 config PPC_64K_PAGES
 	bool "64k page size"
-	depends on !PPC_FSL_BOOK3E && (44x || PPC_BOOK3S_64 || PPC_BOOK3E_64)
+	depends on 44x || PPC_BOOK3S_64
 	select HAVE_ARCH_SOFT_DIRTY if PPC_BOOK3S_64
 
 config PPC_256K_PAGES