Re: [PATCH] [30/30] x86_64: Add missing !X86_PAE dependincy to the2G/2G split.

[Eric Dumazet]

Andi Kleen a écrit :
> From: ebiederm@xxxxxxxxxxxx
>
> When in PAE mode we require that the user kernel divide to be
> on a 1G boundary.  The 2G/2G split does not have that property
> so require !X86_PAE
>
> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> ---
>  arch/i386/Kconfig |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
> index 1a94a73..80003de 100644
> --- a/arch/i386/Kconfig
> +++ b/arch/i386/Kconfig
> @@ -570,6 +570,7 @@ choice
>  		depends on !HIGHMEM
>  		bool "3G/1G user/kernel split (for full 1G low memory)"
>  	config VMSPLIT_2G
> +		depends on !X86_PAE
>  		bool "2G/2G user/kernel split"
>  	config VMSPLIT_1G
>  		bool "1G/3G user/kernel split"

Hum... We lose a usefull 2G/2G split. Should'nt we use a patch to change 
PAGE_OFFSET to 0x8000000 instead of 0x78000000 and keep 2G/2G split ?

Maybe the following patch is better ?

[PATCH] i386 : Adjust CONFIG_PAGE_OFFSET in case of 2G/2G split and X86_PAE

When in PAE mode we require that the user kernel divide to be
on a 1G boundary.  We must therefore make sure PAGE_OFFSET is correctlty 
defined in the 2G/2G split and PAE mode.

Signed-off-by: Eric Dumazet <dada1@xxxxxxxxxxxxx>
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 53d6237..32356f2 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -578,7 +578,8 @@ endchoice
 config PAGE_OFFSET
 	hex
 	default 0xB0000000 if VMSPLIT_3G_OPT
-	default 0x78000000 if VMSPLIT_2G
+	default 0x78000000 if (VMSPLIT_2G && !X86_PAE)
+	default 0x80000000 if (VMSPLIT_2G && X86_PAE)
 	default 0x40000000 if VMSPLIT_1G
 	default 0xC0000000