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Subject: Re: [PATCH] powerpc: Fix determining TI_CPU in
	power_save_ppc32_restore()
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Kumar Gala <galak@kernel.crashing.org>
In-Reply-To: <Pine.LNX.4.64.0808252058320.21303@blarg.am.freescale.net>
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Date: Tue, 26 Aug 2008 14:37:40 +1000
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Cc: linuxppc-dev@ozlabs.org, G.Chen@freescale.com,
	Paul Mackerras <paulus@samba.org>
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>  #ifdef CONFIG_SMP
> -	mfspr	r12,SPRN_SPRG3
> -	lwz	r11,TI_CPU(r12)		/* get cpu number * 4 */
> +	lwz	r11,TI_CPU(r9)		/* get cpu number * 4 */
>  	slwi	r11,r11,2
>  #else
>  	li	r11,0
>  #endif
> +
> +	lwz	r9,_LINK(r11)		/* interrupted in ppc6xx_idle: */
> +	stw	r9,_NIP(r11)		/* make it do a blr */
> +

hrm... you just clobbered r11, won't work very well :-)

Ben.

>  	/* Todo make sure all these are in the same page
>  	 * and load r11 (@ha part + CPU offset) only once
>  	 */
> diff --git a/arch/powerpc/kernel/idle_e500.S b/arch/powerpc/kernel/idle_e500.S
> index 0630403..c9d7234 100644
> --- a/arch/powerpc/kernel/idle_e500.S
> +++ b/arch/powerpc/kernel/idle_e500.S
> @@ -76,18 +76,19 @@ END_FTR_SECTION_IFSET(CPU_FTR_L2CSR|CPU_FTR_CAN_NAP)
>  /*
>   * Return from NAP/DOZE mode, restore some CPU specific registers,
>   * r2 containing physical address of current.
> + * r9 points to thread_info
>   * r11 points to the exception frame (physical address).
>   * We have to preserve r10.
>   */
>  _GLOBAL(power_save_ppc32_restore)
> -	lwz	r9,_LINK(r11)		/* interrupted in e500_idle */
> -	stw	r9,_NIP(r11)		/* make it do a blr */
> -
>  #ifdef CONFIG_SMP
> -	mfspr	r12,SPRN_SPRG3
> -	lwz	r11,TI_CPU(r12)		/* get cpu number * 4 */
> +	lwz	r11,TI_CPU(r9)		/* get cpu number * 4 */
>  	slwi	r11,r11,2
>  #else
>  	li	r11,0
>  #endif
> +
> +	lwz	r9,_LINK(r11)		/* interrupted in e500_idle */
> +	stw	r9,_NIP(r11)		/* make it do a blr */
> +
>  	b	transfer_to_handler_cont