Re: [patch] x86, avx: don't use avx instructions with "noxsave"boot param

From: NeilBrown
Date: Tue Jul 31 2012 - 00:21:41 EST


On Mon, 30 Jul 2012 15:46:15 -0700 Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
wrote:

> Check the kernel has indeed enabled xsave before using AVX instructions.
>
> Fixes the kernel boot panic with "noxsave" boot parameter.
>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>

Looks consistent with other usage - thanks.
Applied.

Should it go in '-stable' kernels too?

NeilBrown

> ---
> arch/x86/include/asm/xor_avx.h | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/xor_avx.h b/arch/x86/include/asm/xor_avx.h
> index 2510d35..77987cd 100644
> --- a/arch/x86/include/asm/xor_avx.h
> +++ b/arch/x86/include/asm/xor_avx.h
> @@ -197,12 +197,12 @@ static struct xor_block_template xor_block_avx = {
>
> #define AVX_XOR_SPEED \
> do { \
> - if (cpu_has_avx) \
> + if (cpu_has_avx && cpu_has_osxsave) \
> xor_speed(&xor_block_avx); \
> } while (0)
>
> #define AVX_SELECT(FASTEST) \
> - (cpu_has_avx ? &xor_block_avx : FASTEST)
> + ((cpu_has_avx && cpu_has_osxsave) ? &xor_block_avx : FASTEST)
>
> #else
>
>

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