| Message ID | 1502286296-27932-1-git-send-email-rosattig@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Aug 09, 2017 at 10:44:56AM -0300, Rodrigo R. Galvao wrote: > From: Nicholas Piggin <npiggin@gmail.com> > > BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1709352 > > 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. > > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > Acked-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> > Tested-by: Anton Blanchard <anton@samba.org> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > (cherry picked from commit 101dd590a7fa37954540cf3149a1c502c0acc524) > Signed-off-by: Rodrigo R. Galvao <rosattig@linux.vnet.ibm.com> This patch had some context differences when I tried to apply it to 4.12 so I cherry picked it directly. That makes me wonder whether you had to fix it up for zesty though; if so the "cherry picked" should be changed to "backported". Otherwise the patch looks fine to me. Acked-by: Seth Forshee <seth.forshee@canonical.com>
On 08/09/17 15:44, Rodrigo R. Galvao wrote: > From: Nicholas Piggin <npiggin@gmail.com> > > BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1709352 > > 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. > > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > Acked-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> > Tested-by: Anton Blanchard <anton@samba.org> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > (cherry picked from commit 101dd590a7fa37954540cf3149a1c502c0acc524) > Signed-off-by: Rodrigo R. Galvao <rosattig@linux.vnet.ibm.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 fb762ee..e003fb9 100644 > --- a/arch/powerpc/kernel/idle_book3s.S > +++ b/arch/powerpc/kernel/idle_book3s.S > @@ -29,6 +29,7 @@ > * Use unused space in the interrupt stack to save and restore > * registers for winkle support. > */ > +#define _MMCR0 GPR0 > #define _SDR1 GPR3 > #define _RPR GPR4 > #define _SPURR GPR5 > @@ -282,6 +283,14 @@ 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. > */ > @@ -434,10 +443,14 @@ FTR_SECTION_ELSE_NESTED(70) > ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_POWER9_DD1, 70) > /* > * 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 > Clean cherry-pick (applies cleanly to zesty/master-next), scope limited to POWER9. Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Applied to zesty/master-next branch fixing the BugLink to the format "http://bugs.launchpad.net/bugs/<bug-id>". Thanks.
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index fb762ee..e003fb9 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -29,6 +29,7 @@ * Use unused space in the interrupt stack to save and restore * registers for winkle support. */ +#define _MMCR0 GPR0 #define _SDR1 GPR3 #define _RPR GPR4 #define _SPURR GPR5 @@ -282,6 +283,14 @@ 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. */ @@ -434,10 +443,14 @@ FTR_SECTION_ELSE_NESTED(70) ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_POWER9_DD1, 70) /* * 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