Re: [PATCH] Make system_reset_pSeries relocatable
From: Balbir Singh <bsingharora@gmail.com>
Date: 2016-07-27 11:34:50
On Wed, Jul 27, 2016 at 05:32:06PM +1000, Balbir Singh wrote:
From: Balbir Singh <bsingharora@gmail.com> Currently the power management bits are broken w.r.t. relocation. There are direct branches from system_reset_pSeries to power7_wakeup_*. The correct way to do it is to do what the slb miss handler does, which is jump to a small stub within the first 64k of the relocated address and then jump to the actual location. The code has been lightly tested (not the kvm bits), I would highly appreciate a review of the code. I suspect there might be easy to find bugs :)
Snip
+ .align 7 +_GLOBAL(power7_wakeup_common) +#ifdef CONFIG_RELOCATABLE + mtctr r11 +#endif + lbz r0,PACA_THREAD_IDLE_STATE(r13) + cmpwi cr2,r0,PNV_THREAD_NAP + bgt cr2,8f /* Either sleep or Winkle */ + + /* Waking up from nap should not cause hypervisor state loss */ + bgt cr3,. + + /* Waking up from nap */ + li r0,PNV_THREAD_RUNNING + stb r0,PACA_THREAD_IDLE_STATE(r13) /* Clear thread state */ + +#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: +#endif + + /* Return SRR1 from power7_nap() */ + mfspr r3,SPRN_SRR1 + beq cr3,2f + b power7_wakeup_noloss +2: b power7_wakeup_loss + + /* Fast Sleep wakeup on PowerNV */ +8: GET_PACA(r13) + b power7_wakeup_tb_loss + /* * Hash table stuff */
As per 0day, this part needs to be under #ifdef CONFIG_PPC_P7_NAP I'll repose a new version tomorrow. Balbir Singh