[PATCH] powerpc: Invalidate ERAT on powersave wakeup for POWER9

[Michael Neuling]

On POWER9 the ERAT may be incorrect on wakeup from some stop states
that lose state. This causes random segvs and illegal instructions
when these stop states are enabled.

This patch invalidates the ERAT on wakeup on POWER9 to prevent this
from causing a problem.

Signed-off-by: Michael Neuling <mi...@neuling.org>
---
 arch/powerpc/kernel/idle_book3s.S | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kernel/idle_book3s.S 
b/arch/powerpc/kernel/idle_book3s.S
index 1ea14b96f1..ace2ad50c8 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -793,6 +793,9 @@ fastsleep_workaround_at_exit:
  */
 .global pnv_wakeup_loss
 pnv_wakeup_loss:
+BEGIN_FTR_SECTION
+       PPC_INVALIDATE_ERAT
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
        ld      r1,PACAR1(r13)
 BEGIN_FTR_SECTION
        CHECK_HMI_INTERRUPT
-- 
2.11.0