From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x242.google.com (mail-pf0-x242.google.com [IPv6:2607:f8b0:400e:c00::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3xCcPr5NVXzDrCw for ; Thu, 20 Jul 2017 11:53:52 +1000 (AEST) Received: by mail-pf0-x242.google.com with SMTP id o88so1234448pfk.1 for ; Wed, 19 Jul 2017 18:53:52 -0700 (PDT) From: Nicholas Piggin To: Michael Ellerman Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, Madhavan Srinivasan , Anton Blanchard , Michael Neuling , Gautham R Shenoy , Vaidyanathan Srinivasan Subject: [PATCH] POWER9 PMU stops after idle workaround Date: Thu, 20 Jul 2017 11:53:22 +1000 Message-Id: <20170720015322.24307-1-npiggin@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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. Signed-off-by: Nicholas Piggin --- 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: -- 2.11.0