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Date: Mon, 30 Apr 2007 10:14:11 +1000
From: Paul Mackerras <paulus@samba.org>
To: Johannes Berg <johannes@sipsolutions.net>
Subject: Re: [PATCH v2] powerpc: fix suspend states again
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Cc: Olof Johansson <olof@lixom.net>, linuxppc-dev@ozlabs.org
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Johannes Berg writes:

> +void save_processor_state(void)
> +{
> +	/* Giveup the lazy FPU & vec so we don't have to back them
> +	 * up from the low level code
> +	 */
> +	enable_kernel_fp();
> +
> +#ifdef CONFIG_ALTIVEC
> +	if (cur_cpu_spec->cpu_features & CPU_FTR_ALTIVEC)
> +		enable_kernel_altivec();
> +#endif /* CONFIG_ALTIVEC */
> +
> +#ifdef CONFIG_SPE
> +	enable_kernel_spe();
> +#endif
> +}

This achieves essentially the same effect as prepare_to_copy() in
arch/powerpc/kernel/process.c, except that we don't end up with fp,
altivec and/or spe enabled - but that's OK since the following code
doesn't actually need fp/altivec/spe.

It would be good to avoid this duplication, or at least to use the
flush_* calls instead of the enable_kernel_* calls.

Paul.