From: Anton Blanchard <anton@ozlabs•org>
To: Nicholas Piggin <npiggin@gmail•com>
Cc: Michael Ellerman <mpe@ellerman•id.au>,
linuxppc-dev@lists•ozlabs.org,
Madhavan Srinivasan <masriniv@in•ibm.com>,
Michael Neuling <mikey@neuling•org>,
Gautham R Shenoy <ego@linux•vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux•vnet.ibm.com>
Subject: Re: [PATCH] POWER9 PMU stops after idle workaround
Date: Wed, 2 Aug 2017 14:30:26 +1000 [thread overview]
Message-ID: <20170802143026.34bbadde@kryten> (raw)
In-Reply-To: <20170720015322.24307-1-npiggin@gmail.com>
Hi Nick,
> POWER9 DD2 PMU can stop after a state-loss idle in some conditions.
>
> A solution is to set then clear MMCRA[60] after wake from state-loss
> idle.
Looks good.
Acked-by: Anton Blanchard <anton@samba•org>
Anton
> Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
> ---
> arch/powerpc/kernel/idle_book3s.S | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kernel/idle_book3s.S
> b/arch/powerpc/kernel/idle_book3s.S index 516ebef905c0..e6252c5a57a4
> 100644 --- a/arch/powerpc/kernel/idle_book3s.S
> +++ b/arch/powerpc/kernel/idle_book3s.S
> @@ -460,11 +460,17 @@ pnv_restore_hyp_resource_arch300:
> /*
> * Workaround for POWER9, if we lost resources, the ERAT
> * might have been mixed up and needs flushing. We also need
> - * to reload MMCR0 (see comment above).
> + * to reload MMCR0 (see comment above). We also need to set
> + * then clear bit 60 in MMCRA to ensure the PMU starts
> running. */
> blt cr3,1f
> PPC_INVALIDATE_ERAT
> ld r1,PACAR1(r13)
> + mfspr r4,SPRN_MMCRA
> + ori r4,r4,(1 << (63-60))
> + mtspr SPRN_MMCRA,r4
> + xori r4,r4,(1 << (63-60))
> + mtspr SPRN_MMCRA,r4
> ld r4,_MMCR0(r1)
> mtspr SPRN_MMCR0,r4
> 1:
next prev parent reply other threads:[~2017-08-02 4:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-20 1:53 [PATCH] POWER9 PMU stops after idle workaround Nicholas Piggin
2017-07-20 4:13 ` Madhavan Srinivasan
2017-07-20 5:06 ` Vaidyanathan Srinivasan
2017-08-02 4:30 ` Anton Blanchard [this message]
2017-08-03 10:19 ` Michael Ellerman
2017-09-13 16:11 ` Michal Suchánek
2017-09-13 20:45 ` Michael Ellerman
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