From ec4867355244755fb5c06037ad2fff760701b465 Mon Sep 17 00:00:00 2001 From: "Gautham R. Shenoy" Date: Tue, 16 May 2017 14:19:44 +0530 Subject: [PATCH] powerpc/powernv/idle: Decouple Timebase restore & Per-core SPRs restore On POWER8, in case of - nap: both timebase and hypervisor state is retained. - fast-sleep: timebase is lost. But the hypervisor state is retained. - winkle: timebase and hypervisor state is lost. Hence, the current code for handling exit from a idle state assumes that if the timebase value is retained, then so is the hypervisor state. Thus, the current code doesn't restore per-core hypervisor state in such cases. But that is no longer the case on POWER9 where we do have stop states in which timebase value is retained, but the hypervisor state is lost. So we have to ensure that the per-core hypervisor state gets restored in such cases. Fix this by ensuring that even in the case when timebase is retained, we explicitly check if we are waking up from a deep stop that loses per-core hypervisor state (indicated by cr4 being eq or gt), and if this is the case, we restore the per-core hypervisor state. Signed-off-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman --- 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 4898d676dcae..afd029f1039b 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -731,13 +731,14 @@ 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. */ +.Ltb_resynced: blt cr4,clear_lock /*