On Tue, 16 May 2017 14:19:45 +0530 "Gautham R. Shenoy" <e...@linux.vnet.ibm.com> wrote:
> From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com> > > On wakeup from a deep stop state which is supposed to lose the > hypervisor state, we don't restore the LPCR to the old value but set > it to a "sane" value via cur_cpu_spec->cpu_restore(). > > The problem is that the "sane" value doesn't include UPRT and the HR > bits which are required to run correctly in Radix mode. > > Fix this on POWER9 onwards by restoring the LPCR value whatever it was > before executing the stop instruction. > > Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com> Yes I think we need this. I have a plan to rework some of that cpu_restore and early CPU init stuff, but for now we need this. Does the OCC restore LPCR properly then we just trash it with ->cpu_restore(), or is it always junk? Reviewed-by: Nicholas Piggin <npig...@gmail.com> > --- > arch/powerpc/kernel/idle_book3s.S | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kernel/idle_book3s.S > b/arch/powerpc/kernel/idle_book3s.S > index afd029f..6c9920d 100644 > --- a/arch/powerpc/kernel/idle_book3s.S > +++ b/arch/powerpc/kernel/idle_book3s.S > @@ -31,6 +31,7 @@ > * registers for winkle support. > */ > #define _SDR1 GPR3 > +#define _PTCR GPR3 > #define _RPR GPR4 > #define _SPURR GPR5 > #define _PURR GPR6 > @@ -39,7 +40,7 @@ > #define _AMOR GPR9 > #define _WORT GPR10 > #define _WORC GPR11 > -#define _PTCR GPR12 > +#define _LPCR GPR12 > > #define PSSCR_EC_ESL_MASK_SHIFTED (PSSCR_EC | PSSCR_ESL) >> 16 > > @@ -55,12 +56,14 @@ save_sprs_to_stack: > * here since any thread in the core might wake up first > */ > BEGIN_FTR_SECTION > - mfspr r3,SPRN_PTCR > - std r3,_PTCR(r1) > /* > * Note - SDR1 is dropped in Power ISA v3. Hence not restoring > * SDR1 here > */ > + mfspr r3,SPRN_PTCR > + std r3,_PTCR(r1) > + mfspr r3,SPRN_LPCR > + std r3,_LPCR(r1) > FTR_SECTION_ELSE > mfspr r3,SPRN_SDR1 > std r3,_SDR1(r1) > @@ -813,6 +816,10 @@ no_segments: > mtctr r12 > bctrl > > +BEGIN_FTR_SECTION > + ld r4,_LPCR(r1) > + mtspr SPRN_LPCR,r4 > +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) > hypervisor_state_restored: > > mtspr SPRN_SRR1,r16
