From: Nicholas Piggin <npiggin@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>,
linuxppc-dev@lists.ozlabs.org,
Madhavan Srinivasan <masriniv@in.ibm.com>,
Anton Blanchard <anton@samba.org>,
Michael Neuling <mikey@neuling.org>,
Gautham R Shenoy <ego@linux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Subject: [PATCH] POWER9 PMU stops after idle workaround
Date: Thu, 20 Jul 2017 11:53:22 +1000 [thread overview]
Message-ID: <20170720015322.24307-1-npiggin@gmail.com> (raw)
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 <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:
--
2.11.0
next reply other threads:[~2017-07-20 1:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-20 1:53 Nicholas Piggin [this message]
2017-07-20 4:13 ` [PATCH] POWER9 PMU stops after idle workaround Madhavan Srinivasan
2017-07-20 5:06 ` Vaidyanathan Srinivasan
2017-08-02 4:30 ` Anton Blanchard
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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