[PATCH 21/33] powerpc/64s/exception: soft nmi interrupt should not use ret_from_except

From: Michal Suchanek
Date: Tue Nov 12 2019 - 11:55:15 EST


From: Nicholas Piggin <npiggin@xxxxxxxxx>

The soft nmi handler does not reconcile interrupt state, so it should
not return via the normal ret_from_except path. Return like other NMIs,
using the EXCEPTION_RESTORE_REGS macro.

This becomes important when the scv interrupt is implemented, which
must handle soft-masked interrupts that have r13 set to something other
than the PACA -- returning to kernel in this case must restore r13.

Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/kernel/exceptions-64s.S | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 38bc66b95516..af1264cd005f 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -2740,7 +2740,11 @@ EXC_COMMON_BEGIN(soft_nmi_common)
bl save_nvgprs
addi r3,r1,STACK_FRAME_OVERHEAD
bl soft_nmi_interrupt
- b ret_from_except
+ /* Clear MSR_RI before setting SRR0 and SRR1. */
+ li r9,0
+ mtmsrd r9,1
+ EXCEPTION_RESTORE_REGS hsrr=0
+ RFI_TO_KERNEL

#endif /* CONFIG_PPC_WATCHDOG */

--
2.23.0