diff options
Diffstat (limited to 'arch/powerpc/kernel/idle_book3s.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 65 |
1 files changed, 63 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 516ebef905c0..4621568277f2 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 /* @@ -803,9 +857,16 @@ 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: |