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-rw-r--r--arch/powerpc/kernel/idle_book3s.S130
1 files changed, 114 insertions, 16 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index e6252c5a57a4..1125c9be9e06 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -85,7 +85,61 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
std r3,_WORT(r1)
mfspr r3,SPRN_WORC
std r3,_WORC(r1)
+/*
+ * On POWER9, there are idle states such as stop4, invoked via cpuidle,
+ * that lose hypervisor resources. In such cases, we need to save
+ * additional SPRs before entering those idle states so that they can
+ * be restored to their older values on wakeup from the idle state.
+ *
+ * On POWER8, the only such deep idle state is winkle which is used
+ * only in the context of CPU-Hotplug, where these additional SPRs are
+ * reinitiazed to a sane value. Hence there is no need to save/restore
+ * these SPRs.
+ */
+BEGIN_FTR_SECTION
+ blr
+END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
+
+power9_save_additional_sprs:
+ mfspr r3, SPRN_PID
+ mfspr r4, SPRN_LDBAR
+ std r3, STOP_PID(r13)
+ std r4, STOP_LDBAR(r13)
+ mfspr r3, SPRN_FSCR
+ mfspr r4, SPRN_HFSCR
+ std r3, STOP_FSCR(r13)
+ std r4, STOP_HFSCR(r13)
+
+ mfspr r3, SPRN_MMCRA
+ mfspr r4, SPRN_MMCR1
+ std r3, STOP_MMCRA(r13)
+ std r4, STOP_MMCR1(r13)
+
+ mfspr r3, SPRN_MMCR2
+ std r3, STOP_MMCR2(r13)
+ blr
+
+power9_restore_additional_sprs:
+ ld r3,_LPCR(r1)
+ ld r4, STOP_PID(r13)
+ mtspr SPRN_LPCR,r3
+ mtspr SPRN_PID, r4
+
+ ld r3, STOP_LDBAR(r13)
+ ld r4, STOP_FSCR(r13)
+ mtspr SPRN_LDBAR, r3
+ mtspr SPRN_FSCR, r4
+
+ ld r3, STOP_HFSCR(r13)
+ ld r4, STOP_MMCRA(r13)
+ mtspr SPRN_HFSCR, r3
+ mtspr SPRN_MMCRA, r4
+ /* We have already restored PACA_MMCR0 */
+ ld r3, STOP_MMCR1(r13)
+ ld r4, STOP_MMCR2(r13)
+ mtspr SPRN_MMCR1, r3
+ mtspr SPRN_MMCR2, r4
blr
/*
@@ -141,7 +195,16 @@ pnv_powersave_common:
std r5,_CCR(r1)
std r1,PACAR1(r13)
+BEGIN_FTR_SECTION
+ /*
+ * POWER9 does not require real mode to stop, and presently does not
+ * set hwthread_state for KVM (threads don't share MMU context), so
+ * we can remain in virtual mode for this.
+ */
+ bctr
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
/*
+ * POWER8
* Go to real mode to do the nap, as required by the architecture.
* Also, we need to be in real mode before setting hwthread_state,
* because as soon as we do that, another thread can switch
@@ -151,6 +214,20 @@ pnv_powersave_common:
mtmsrd r7,0
bctr
+/*
+ * This is the sequence required to execute idle instructions, as
+ * specified in ISA v2.07 (and earlier). MSR[IR] and MSR[DR] must be 0.
+ */
+#define IDLE_STATE_ENTER_SEQ_NORET(IDLE_INST) \
+ /* Magic NAP/SLEEP/WINKLE mode enter sequence */ \
+ std r0,0(r1); \
+ ptesync; \
+ ld r0,0(r1); \
+236: cmpd cr0,r0,r0; \
+ bne 236b; \
+ IDLE_INST;
+
+
.globl pnv_enter_arch207_idle_mode
pnv_enter_arch207_idle_mode:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
@@ -242,20 +319,27 @@ enter_winkle:
/*
* r3 - PSSCR value corresponding to the requested stop state.
*/
-power_enter_stop:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
- /* Tell KVM we're entering idle */
+power_enter_stop_kvm_rm:
+ /*
+ * This is currently unused because POWER9 KVM does not have to
+ * gather secondary threads into sibling mode, but the code is
+ * here in case that function is required.
+ *
+ * Tell KVM we're entering idle.
+ */
li r4,KVM_HWTHREAD_IN_IDLE
/* DO THIS IN REAL MODE! See comment above. */
stb r4,HSTATE_HWTHREAD_STATE(r13)
#endif
+power_enter_stop:
/*
* Check if we are executing the lite variant with ESL=EC=0
*/
andis. r4,r3,PSSCR_EC_ESL_MASK_SHIFTED
clrldi r3,r3,60 /* r3 = Bits[60:63] = Requested Level (RL) */
bne .Lhandle_esl_ec_set
- IDLE_STATE_ENTER_SEQ(PPC_STOP)
+ PPC_STOP
li r3,0 /* Since we didn't lose state, return 0 */
/*
@@ -288,7 +372,8 @@ power_enter_stop:
ld r4,ADDROFF(pnv_first_deep_stop_state)(r5)
cmpd r3,r4
bge .Lhandle_deep_stop
- IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
+ PPC_STOP /* Does not return (system reset interrupt) */
+
.Lhandle_deep_stop:
/*
* Entering deep idle state.
@@ -310,7 +395,7 @@ lwarx_loop_stop:
bl save_sprs_to_stack
- IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP)
+ PPC_STOP /* Does not return (system reset interrupt) */
/*
* Entered with MSR[EE]=0 and no soft-masked interrupts pending.
@@ -411,6 +496,18 @@ pnv_powersave_wakeup_mce:
b pnv_powersave_wakeup
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+kvm_start_guest_check:
+ li r0,KVM_HWTHREAD_IN_KERNEL
+ stb r0,HSTATE_HWTHREAD_STATE(r13)
+ /* Order setting hwthread_state vs. testing hwthread_req */
+ sync
+ lbz r0,HSTATE_HWTHREAD_REQ(r13)
+ cmpwi r0,0
+ beqlr
+ b kvm_start_guest
+#endif
+
/*
* Called from reset vector for powersave wakeups.
* cr3 - set to gt if waking up with partial/complete hypervisor state loss
@@ -435,15 +532,9 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
mr r3,r12
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
- li r0,KVM_HWTHREAD_IN_KERNEL
- stb r0,HSTATE_HWTHREAD_STATE(r13)
- /* Order setting hwthread_state vs. testing hwthread_req */
- sync
- lbz r0,HSTATE_HWTHREAD_REQ(r13)
- cmpwi r0,0
- beq 1f
- b kvm_start_guest
-1:
+BEGIN_FTR_SECTION
+ bl kvm_start_guest_check
+END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
#endif
/* Return SRR1 from power7_nap() */
@@ -809,9 +900,16 @@ no_segments:
mtctr r12
bctrl
+/*
+ * On POWER9, we can come here on wakeup from a cpuidle stop state.
+ * Hence restore the additional SPRs to the saved value.
+ *
+ * On POWER8, we come here only on winkle. Since winkle is used
+ * only in the case of CPU-Hotplug, we don't need to restore
+ * the additional SPRs.
+ */
BEGIN_FTR_SECTION
- ld r4,_LPCR(r1)
- mtspr SPRN_LPCR,r4
+ bl power9_restore_additional_sprs
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
hypervisor_state_restored: