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Subject: Re: [PATCH 2/3] powerpc: POWER7 optimised memcpy using VMX
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Anton Blanchard <anton@samba.org>
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Date: Fri, 17 Jun 2011 15:57:16 +1000
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O
> +.Lvmx_copy:
> +	mflr	r0
> +	std	r4,56(r1)
> +	std	r5,64(r1)
> +	std	r0,16(r1)
> +	stdu	r1,-STACKFRAMESIZE(r1)
> +	bl	.enable_kernel_altivec
> +	ld	r0,STACKFRAMESIZE+16(r1)
> +	ld	r3,STACKFRAMESIZE+48(r1)
> +	ld	r4,STACKFRAMESIZE+56(r1)
> +	ld	r5,STACKFRAMESIZE+64(r1)
> +	mtlr	r0

Disable interrupts ? We wont save the VMX state on interrupts and memcpy
is definitely re-entrant.

Or only run the optimization when not at interrupt time....

Cheers,
Ben.