On 24/07/20 6:55 am, Michael Neuling wrote:
On Fri, 2020-07-10 at 10:52 +0530, Pratik Rajesh Sampat wrote:
Additional registers DAWR0, DAWRX0 may be lost on Power 10 for
stop levels < 4.
Therefore save the values of these SPRs before entering a "stop"
state and restore their values on wakeup.
Signed-off-by: Pratik Rajesh Sampat <psam...@linux.ibm.com>
---
arch/powerpc/platforms/powernv/idle.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/idle.c
b/arch/powerpc/platforms/powernv/idle.c
index 19d94d021357..f2e2a6a4c274 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -600,6 +600,8 @@ struct p9_sprs {
u64 iamr;
u64 amor;
u64 uamor;
+ u64 dawr0;
+ u64 dawrx0;
};
static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
@@ -687,6 +689,10 @@ static unsigned long power9_idle_stop(unsigned long
psscr, bool mmu_on)
sprs.iamr = mfspr(SPRN_IAMR);
sprs.amor = mfspr(SPRN_AMOR);
sprs.uamor = mfspr(SPRN_UAMOR);
+ if (cpu_has_feature(CPU_FTR_ARCH_31)) {
You are actually viewing an old version of the patches
The main point of change were based on comments from Nick Piggin, I
have changed the top level function check from ARCH_300 to a P9 PVR
check instead.
A similar thing needs to be done for P10, however as the P10 PVR isn't
exposed yet, I've shelved this particular patch.
Nick's comment to check based on PVR:https://lkml.org/lkml/2020/7/13/1018
v4 of the series:https://lkml.org/lkml/2020/7/21/784
Thanks for your review,
Pratik
Can you add a comment here saying even though DAWR0 is ARCH_30, it's only
required to be saved on 31. Otherwise this looks pretty odd.
+ sprs.dawr0 = mfspr(SPRN_DAWR0);
+ sprs.dawrx0 = mfspr(SPRN_DAWRX0);
+ }
srr1 = isa300_idle_stop_mayloss(psscr); /* go idle */
@@ -710,6 +716,10 @@ static unsigned long power9_idle_stop(unsigned long
psscr, bool mmu_on)
mtspr(SPRN_IAMR, sprs.iamr);
mtspr(SPRN_AMOR, sprs.amor);
mtspr(SPRN_UAMOR, sprs.uamor);
+ if (cpu_has_feature(CPU_FTR_ARCH_31)) {
+ mtspr(SPRN_DAWR0, sprs.dawr0);
+ mtspr(SPRN_DAWRX0, sprs.dawrx0);
+ }
/*
* Workaround for POWER9 DD2.0, if we lost resources, the ERAT
