Re: [PATCH] Add VDSO time function support for x86 32-bit kernel

[H. Peter Anvin]

On 12/12/2012 12:19 PM, stefani@xxxxxxxxxxx wrote:
> diff --git a/arch/x86/vdso/vdso32/vclock_gettime.c b/arch/x86/vdso/vdso32/vclock_gettime.c
> new file mode 100644
> index 0000000..c9a1909
> --- /dev/null
> +++ b/arch/x86/vdso/vdso32/vclock_gettime.c
> @@ -0,0 +1,7 @@
> +/*
> + * since vgtod layout differs between X86_64 and x86_32, it is not possible to
> + * provide a 32 bit vclock with a 64 bit kernel
> + */
> +#ifdef CONFIG_X86_32
> +#include "../vclock_gettime.c"
> +#endif

This is where this goes fail.  Sorry, it is not acceptable to introduce 
an ABI on x86-32 without providing it also on x86-64 in compatibility mode.

I also don't believe it is not possible... it might require some more 
cleverness; perhaps we need to do the 32-bit vgtod in such a way that it 
*is* compatible with 64 bits.

	-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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