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Subject[PATCH 2/3] powernv:idle: Decouple TB restore & Per-core SPRs restore
From: "Gautham R. Shenoy" <>

The idle-exit code assumes that if Timebase is not lost, then neither
are the per-core hypervisor resources lost. This was true on POWER8
where fast-sleep lost only TB but not per-core resources, and winkle
lost both.

This assumption is not true for POWER9 however, since there can be
states which do not lose timebase but can lose per-core SPRs.

Hence check if we need to restore the per-core hypervisor state even
if timebase is not lost.

Signed-off-by: Gautham R. Shenoy <>
arch/powerpc/kernel/idle_book3s.S | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 9b747e9..6a9bd28 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -723,13 +723,14 @@ timebase_resync:
* Use cr3 which indicates that we are waking up with atleast partial
* hypervisor state loss to determine if TIMEBASE RESYNC is needed.
- ble cr3,clear_lock
+ ble cr3,.Ltb_resynced
/* Time base re-sync */
bl opal_resync_timebase;
- * If waking up from sleep, per core state is not lost, skip to
- * clear_lock.
+ * If waking up from sleep (POWER8), per core state
+ * is not lost, skip to clear_lock.
blt cr4,clear_lock

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