Re: [RFC PATCH] Make AT_VECTOR_SIZE_ARCH 2 for x86-32

["Serge E. Hallyn" <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

Quoting Serge E. Hallyn (serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
> [ RFC:  Am I on crack? ]
> 
> Both x86-32 and x86-64 with 32-bit compat use ARCH_DLINFO_IA32,
> which defines two saved_auxv entries.  But system.h only defines
> AT_VECTOR_SIZE_ARCH as 2 for CONFIG_IA32_EMULATION, not for
> CONFIG_X86_32.  Fix that.

To be clear, this patch if right would be for pushing upstream
immediately.  It still leaves open the question of what we want
to do about saved_auxv.  We currently just write it out as a
buffer, but since it is actually an array of longs, and therefore
differently sized on x86-32 and x86-64-compat, we would need to
write them out entry-by-entry (and validate no overflows for
TIF_IA32 tasks).  Does that seem warranted?

> Signed-off-by: Serge E. Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> ---
>  arch/x86/include/asm/system.h |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
> index ecb544e..e04740f 100644
> --- a/arch/x86/include/asm/system.h
> +++ b/arch/x86/include/asm/system.h
> @@ -11,9 +11,9 @@
>  #include <linux/irqflags.h>
> 
>  /* entries in ARCH_DLINFO: */
> -#ifdef CONFIG_IA32_EMULATION
> +#if defined(CONFIG_IA32_EMULATION) || !defined(CONFIG_X86_64)
>  # define AT_VECTOR_SIZE_ARCH 2
> -#else
> +#else /* else it's non-compat x86-64 */
>  # define AT_VECTOR_SIZE_ARCH 1
>  #endif
> 
> -- 
> 1.6.0.4
> 
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