[PATCH 1/2] powerpc/47x: Disable 256k page size

[PATCH 1/2] powerpc/47x: Disable 256k page size

[Christophe Leroy]

PPC47x_TLBE_SIZE isn't defined for 256k pages, so
this size of page shall not be selected for 47x.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: e7f75ad01d59 ("powerpc/47x: Base ppc476 support")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 107bb4319e0e..a685e42d3993 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -772,7 +772,7 @@ config PPC_64K_PAGES
 
 config PPC_256K_PAGES
 	bool "256k page size"
-	depends on 44x && !STDBINUTILS
+	depends on 44x && !STDBINUTILS && !PPC_47x
 	help
 	  Make the page size 256k.
 
-- 
2.25.0

[PATCH 2/2] powerpc/44x: Remove STDBINUTILS kconfig option

[Christophe Leroy]

STDBINUTILS is just a toggle to allow 256k page size
to appear in the possible page sizes list for the 44x.

Make 256k page size appear all the time with an
explicit warning on binutils, and remove this unneccessary
STDBINUTILS config option.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/Kconfig | 27 +++++++--------------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index a685e42d3993..3e29995540a7 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -720,18 +720,6 @@ config ARCH_MEMORY_PROBE
 	def_bool y
 	depends on MEMORY_HOTPLUG
 
-config STDBINUTILS
-	bool "Using standard binutils settings"
-	depends on 44x
-	default y
-	help
-	  Turning this option off allows you to select 256KB PAGE_SIZE on 44x.
-	  Note, that kernel will be able to run only those applications,
-	  which had been compiled using binutils later than 2.17.50.0.3 with
-	  '-zmax-page-size' set to 256K (the default is 64K). Or, if using
-	  the older binutils, you can patch them with a trivial patch, which
-	  changes the ELF_MAXPAGESIZE definition from 0x10000 to 0x40000.
-
 choice
 	prompt "Page size"
 	default PPC_4K_PAGES
@@ -771,17 +759,16 @@ config PPC_64K_PAGES
 	select HAVE_ARCH_SOFT_DIRTY if PPC_BOOK3S_64
 
 config PPC_256K_PAGES
-	bool "256k page size"
-	depends on 44x && !STDBINUTILS && !PPC_47x
+	bool "256k page size (Requires non-standard binutils settings)"
+	depends on 44x && !PPC_47x
 	help
 	  Make the page size 256k.
 
-	  As the ELF standard only requires alignment to support page
-	  sizes up to 64k, you will need to compile all of your user
-	  space applications with a non-standard binutils settings
-	  (see the STDBINUTILS description for details).
-
-	  Say N unless you know what you are doing.
+	  That kernel will be able to run only those applications,
+	  which had been compiled using binutils later than 2.17.50.0.3 with
+	  '-zmax-page-size' set to 256K (the default is 64K). Or, if using
+	  the older binutils, you can patch them with a trivial patch, which
+	  changes the ELF_MAXPAGESIZE definition from 0x10000 to 0x40000.
 
 endchoice
 
-- 
2.25.0

RE: [PATCH 2/2] powerpc/44x: Remove STDBINUTILS kconfig option

[David Laight]

From: Christophe Leroy
> Sent: 20 January 2021 07:49
> 
> STDBINUTILS is just a toggle to allow 256k page size
> to appear in the possible page sizes list for the 44x.
> 
> Make 256k page size appear all the time with an
> explicit warning on binutils, and remove this unneccessary
> STDBINUTILS config option.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
>  arch/powerpc/Kconfig | 27 +++++++--------------------
>  1 file changed, 7 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index a685e42d3993..3e29995540a7 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -720,18 +720,6 @@ config ARCH_MEMORY_PROBE
>  	def_bool y
>  	depends on MEMORY_HOTPLUG
> 
> -config STDBINUTILS
> -	bool "Using standard binutils settings"
> -	depends on 44x
> -	default y
> -	help
> -	  Turning this option off allows you to select 256KB PAGE_SIZE on 44x.
> -	  Note, that kernel will be able to run only those applications,
> -	  which had been compiled using binutils later than 2.17.50.0.3 with
> -	  '-zmax-page-size' set to 256K (the default is 64K). Or, if using
> -	  the older binutils, you can patch them with a trivial patch, which
> -	  changes the ELF_MAXPAGESIZE definition from 0x10000 to 0x40000.
> -
>  choice
>  	prompt "Page size"
>  	default PPC_4K_PAGES
> @@ -771,17 +759,16 @@ config PPC_64K_PAGES
>  	select HAVE_ARCH_SOFT_DIRTY if PPC_BOOK3S_64
> 
>  config PPC_256K_PAGES
> -	bool "256k page size"
> -	depends on 44x && !STDBINUTILS && !PPC_47x
> +	bool "256k page size (Requires non-standard binutils settings)"
> +	depends on 44x && !PPC_47x
>  	help
>  	  Make the page size 256k.
> 
> -	  As the ELF standard only requires alignment to support page
> -	  sizes up to 64k, you will need to compile all of your user
> -	  space applications with a non-standard binutils settings
> -	  (see the STDBINUTILS description for details).
> -
> -	  Say N unless you know what you are doing.
> +	  That kernel will be able to run only those applications,
> +	  which had been compiled using binutils later than 2.17.50.0.3 with
> +	  '-zmax-page-size' set to 256K (the default is 64K). Or, if using
> +	  the older binutils, you can patch them with a trivial patch, which
> +	  changes the ELF_MAXPAGESIZE definition from 0x10000 to 0x40000.


The kernel will only be able to run applications that have been
compiled with '-zmax-page-size' set to 256K (the default is 64K)
using binutils later than 2.17.50.0.3, or by patching the
ELF_MAXPAGESIZE definition from 0x10000 to 0x40000 in older versions.

> 
>  endchoice
> 
> --
> 2.25.0

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

Re: [PATCH 1/2] powerpc/47x: Disable 256k page size

[Michael Ellerman]

On Wed, 20 Jan 2021 07:49:13 +0000 (UTC), Christophe Leroy wrote:
> PPC47x_TLBE_SIZE isn't defined for 256k pages, so
> this size of page shall not be selected for 47x.

Applied to powerpc/next.

[1/2] powerpc/47x: Disable 256k page size
      https://git.kernel.org/powerpc/c/910a0cb6d259736a0c86e795d4c2f42af8d0d775
[2/2] powerpc/44x: Remove STDBINUTILS kconfig option
      https://git.kernel.org/powerpc/c/4eeef098b43242ed145c83fba9989d586d707589

cheers