linux-kernel - Re: [PATCH 1/2] powerpc/powernv/idle: Exclude mfspr on HID1,4,5 on P9 and above

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Date:   Thu, 9 Jul 2020 14:31:11 +0530
From:   Gautham R Shenoy <ego@...ux.vnet.ibm.com>
To:     Pratik Rajesh Sampat <psampat@...ux.ibm.com>
Cc:     mpe@...erman.id.au, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org, benh@...nel.crashing.org,
        paulus@...ba.org, ego@...ux.vnet.ibm.com, svaidy@...ux.ibm.com,
        pratik.r.sampat@...il.com
Subject: Re: [PATCH 1/2] powerpc/powernv/idle: Exclude mfspr on HID1,4,5 on
 P9 and above

On Fri, Jul 03, 2020 at 06:16:39PM +0530, Pratik Rajesh Sampat wrote:
> POWER9 onwards the support for the registers HID1, HID4, HID5 has been
> receded.
> Although mfspr on the above registers worked in Power9, In Power10
> simulator is unrecognized. Moving their assignment under the
> check for machines lower than Power9
> 
> Signed-off-by: Pratik Rajesh Sampat <psampat@...ux.ibm.com>

Nice catch.

Reviewed-by: Gautham R. Shenoy <ego@...ux.vnet.ibm.com>

> ---
>  arch/powerpc/platforms/powernv/idle.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> index 2dd467383a88..19d94d021357 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -73,9 +73,6 @@ static int pnv_save_sprs_for_deep_states(void)
>  	 */
>  	uint64_t lpcr_val	= mfspr(SPRN_LPCR);
>  	uint64_t hid0_val	= mfspr(SPRN_HID0);
> -	uint64_t hid1_val	= mfspr(SPRN_HID1);
> -	uint64_t hid4_val	= mfspr(SPRN_HID4);
> -	uint64_t hid5_val	= mfspr(SPRN_HID5);
>  	uint64_t hmeer_val	= mfspr(SPRN_HMEER);
>  	uint64_t msr_val = MSR_IDLE;
>  	uint64_t psscr_val = pnv_deepest_stop_psscr_val;
> @@ -117,6 +114,9 @@ static int pnv_save_sprs_for_deep_states(void)
> 
>  			/* Only p8 needs to set extra HID regiters */
>  			if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
> +				uint64_t hid1_val = mfspr(SPRN_HID1);
> +				uint64_t hid4_val = mfspr(SPRN_HID4);
> +				uint64_t hid5_val = mfspr(SPRN_HID5);
> 
>  				rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val);
>  				if (rc != 0)
> -- 
> 2.25.4
> 
--
Thanks and Regards
gautham.