Hi Nick, > POWER9 DD2 can see spurious PMU interrupts after state-loss idle in > some conditions. > > A solution is to save and reload MMCR0 over state-loss idle.
Thanks, looks good. Tested-by: Anton Blanchard <an...@samba.org> Anton > Signed-off-by: Nicholas Piggin <npig...@gmail.com> > --- > arch/powerpc/kernel/idle_book3s.S | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kernel/idle_book3s.S > b/arch/powerpc/kernel/idle_book3s.S index 5adb390e773b..516ebef905c0 > 100644 --- a/arch/powerpc/kernel/idle_book3s.S > +++ b/arch/powerpc/kernel/idle_book3s.S > @@ -30,6 +30,7 @@ > * Use unused space in the interrupt stack to save and restore > * registers for winkle support. > */ > +#define _MMCR0 GPR0 > #define _SDR1 GPR3 > #define _PTCR GPR3 > #define _RPR GPR4 > @@ -272,6 +273,14 @@ power_enter_stop: > b pnv_wakeup_noloss > > .Lhandle_esl_ec_set: > + /* > + * POWER9 DD2 can incorrectly set PMAO when waking up after a > + * state-loss idle. Saving and restoring MMCR0 over idle is a > + * workaround. > + */ > + mfspr r4,SPRN_MMCR0 > + std r4,_MMCR0(r1) > + > /* > * Check if the requested state is a deep idle state. > */ > @@ -450,10 +459,14 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300) > pnv_restore_hyp_resource_arch300: > /* > * Workaround for POWER9, if we lost resources, the ERAT > - * might have been mixed up and needs flushing. > + * might have been mixed up and needs flushing. We also need > + * to reload MMCR0 (see comment above). > */ > blt cr3,1f > PPC_INVALIDATE_ERAT > + ld r1,PACAR1(r13) > + ld r4,_MMCR0(r1) > + mtspr SPRN_MMCR0,r4 > 1: > /* > * POWER ISA 3. Use PSSCR to determine if we
