[PATCH] POWER9 PMU stops after idle workaround
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2017-07-20 01:53:52
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
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