diff options
Diffstat (limited to 'arch/powerpc/kernel/idle_power7.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_power7.S | 511 |
1 files changed, 511 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S new file mode 100644 index 000000000..ccde8f084 --- /dev/null +++ b/arch/powerpc/kernel/idle_power7.S @@ -0,0 +1,511 @@ +/* + * This file contains the power_save function for Power7 CPUs. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/threads.h> +#include <asm/processor.h> +#include <asm/page.h> +#include <asm/cputable.h> +#include <asm/thread_info.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> +#include <asm/ppc-opcode.h> +#include <asm/hw_irq.h> +#include <asm/kvm_book3s_asm.h> +#include <asm/opal.h> +#include <asm/cpuidle.h> +#include <asm/mmu-hash64.h> + +#undef DEBUG + +/* + * Use unused space in the interrupt stack to save and restore + * registers for winkle support. + */ +#define _SDR1 GPR3 +#define _RPR GPR4 +#define _SPURR GPR5 +#define _PURR GPR6 +#define _TSCR GPR7 +#define _DSCR GPR8 +#define _AMOR GPR9 +#define _WORT GPR10 +#define _WORC GPR11 + +/* Idle state entry routines */ + +#define IDLE_STATE_ENTER_SEQ(IDLE_INST) \ + /* Magic NAP/SLEEP/WINKLE mode enter sequence */ \ + std r0,0(r1); \ + ptesync; \ + ld r0,0(r1); \ +1: cmp cr0,r0,r0; \ + bne 1b; \ + IDLE_INST; \ + b . + + .text + +/* + * Pass requested state in r3: + * r3 - PNV_THREAD_NAP/SLEEP/WINKLE + * + * To check IRQ_HAPPENED in r4 + * 0 - don't check + * 1 - check + */ +_GLOBAL(power7_powersave_common) + /* Use r3 to pass state nap/sleep/winkle */ + /* NAP is a state loss, we create a regs frame on the + * stack, fill it up with the state we care about and + * stick a pointer to it in PACAR1. We really only + * need to save PC, some CR bits and the NV GPRs, + * but for now an interrupt frame will do. + */ + mflr r0 + std r0,16(r1) + stdu r1,-INT_FRAME_SIZE(r1) + std r0,_LINK(r1) + std r0,_NIP(r1) + +#ifndef CONFIG_SMP + /* Make sure FPU, VSX etc... are flushed as we may lose + * state when going to nap mode + */ + bl discard_lazy_cpu_state +#endif /* CONFIG_SMP */ + + /* Hard disable interrupts */ + mfmsr r9 + rldicl r9,r9,48,1 + rotldi r9,r9,16 + mtmsrd r9,1 /* hard-disable interrupts */ + + /* Check if something happened while soft-disabled */ + lbz r0,PACAIRQHAPPENED(r13) + andi. r0,r0,~PACA_IRQ_HARD_DIS@l + beq 1f + cmpwi cr0,r4,0 + beq 1f + addi r1,r1,INT_FRAME_SIZE + ld r0,16(r1) + li r3,0 /* Return 0 (no nap) */ + mtlr r0 + blr + +1: /* We mark irqs hard disabled as this is the state we'll + * be in when returning and we need to tell arch_local_irq_restore() + * about it + */ + li r0,PACA_IRQ_HARD_DIS + stb r0,PACAIRQHAPPENED(r13) + + /* We haven't lost state ... yet */ + li r0,0 + stb r0,PACA_NAPSTATELOST(r13) + + /* Continue saving state */ + SAVE_GPR(2, r1) + SAVE_NVGPRS(r1) + mfcr r4 + std r4,_CCR(r1) + std r9,_MSR(r1) + std r1,PACAR1(r13) + + /* + * 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 + * the MMU context to the guest. + */ + LOAD_REG_IMMEDIATE(r5, MSR_IDLE) + li r6, MSR_RI + andc r6, r9, r6 + LOAD_REG_ADDR(r7, power7_enter_nap_mode) + mtmsrd r6, 1 /* clear RI before setting SRR0/1 */ + mtspr SPRN_SRR0, r7 + mtspr SPRN_SRR1, r5 + rfid + + .globl power7_enter_nap_mode +power7_enter_nap_mode: +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE + /* Tell KVM we're napping */ + li r4,KVM_HWTHREAD_IN_NAP + stb r4,HSTATE_HWTHREAD_STATE(r13) +#endif + stb r3,PACA_THREAD_IDLE_STATE(r13) + cmpwi cr3,r3,PNV_THREAD_SLEEP + bge cr3,2f + IDLE_STATE_ENTER_SEQ(PPC_NAP) + /* No return */ +2: + /* Sleep or winkle */ + lbz r7,PACA_THREAD_MASK(r13) + ld r14,PACA_CORE_IDLE_STATE_PTR(r13) +lwarx_loop1: + lwarx r15,0,r14 + andc r15,r15,r7 /* Clear thread bit */ + + andi. r15,r15,PNV_CORE_IDLE_THREAD_BITS + +/* + * If cr0 = 0, then current thread is the last thread of the core entering + * sleep. Last thread needs to execute the hardware bug workaround code if + * required by the platform. + * Make the workaround call unconditionally here. The below branch call is + * patched out when the idle states are discovered if the platform does not + * require it. + */ +.global pnv_fastsleep_workaround_at_entry +pnv_fastsleep_workaround_at_entry: + beq fastsleep_workaround_at_entry + + stwcx. r15,0,r14 + bne- lwarx_loop1 + isync + +common_enter: /* common code for all the threads entering sleep or winkle */ + bgt cr3,enter_winkle + IDLE_STATE_ENTER_SEQ(PPC_SLEEP) + +fastsleep_workaround_at_entry: + ori r15,r15,PNV_CORE_IDLE_LOCK_BIT + stwcx. r15,0,r14 + bne- lwarx_loop1 + isync + + /* Fast sleep workaround */ + li r3,1 + li r4,1 + li r0,OPAL_CONFIG_CPU_IDLE_STATE + bl opal_call_realmode + + /* Clear Lock bit */ + li r0,0 + lwsync + stw r0,0(r14) + b common_enter + +enter_winkle: + /* + * Note all register i.e per-core, per-subcore or per-thread is saved + * here since any thread in the core might wake up first + */ + mfspr r3,SPRN_SDR1 + std r3,_SDR1(r1) + mfspr r3,SPRN_RPR + std r3,_RPR(r1) + mfspr r3,SPRN_SPURR + std r3,_SPURR(r1) + mfspr r3,SPRN_PURR + std r3,_PURR(r1) + mfspr r3,SPRN_TSCR + std r3,_TSCR(r1) + mfspr r3,SPRN_DSCR + std r3,_DSCR(r1) + mfspr r3,SPRN_AMOR + std r3,_AMOR(r1) + mfspr r3,SPRN_WORT + std r3,_WORT(r1) + mfspr r3,SPRN_WORC + std r3,_WORC(r1) + IDLE_STATE_ENTER_SEQ(PPC_WINKLE) + +_GLOBAL(power7_idle) + /* Now check if user or arch enabled NAP mode */ + LOAD_REG_ADDRBASE(r3,powersave_nap) + lwz r4,ADDROFF(powersave_nap)(r3) + cmpwi 0,r4,0 + beqlr + li r3, 1 + /* fall through */ + +_GLOBAL(power7_nap) + mr r4,r3 + li r3,PNV_THREAD_NAP + b power7_powersave_common + /* No return */ + +_GLOBAL(power7_sleep) + li r3,PNV_THREAD_SLEEP + li r4,1 + b power7_powersave_common + /* No return */ + +_GLOBAL(power7_winkle) + li r3,3 + li r4,1 + b power7_powersave_common + /* No return */ + +#define CHECK_HMI_INTERRUPT \ + mfspr r0,SPRN_SRR1; \ +BEGIN_FTR_SECTION_NESTED(66); \ + rlwinm r0,r0,45-31,0xf; /* extract wake reason field (P8) */ \ +FTR_SECTION_ELSE_NESTED(66); \ + rlwinm r0,r0,45-31,0xe; /* P7 wake reason field is 3 bits */ \ +ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \ + cmpwi r0,0xa; /* Hypervisor maintenance ? */ \ + bne 20f; \ + /* Invoke opal call to handle hmi */ \ + ld r2,PACATOC(r13); \ + ld r1,PACAR1(r13); \ + std r3,ORIG_GPR3(r1); /* Save original r3 */ \ + li r0,OPAL_HANDLE_HMI; /* Pass opal token argument*/ \ + bl opal_call_realmode; \ + ld r3,ORIG_GPR3(r1); /* Restore original r3 */ \ +20: nop; + + +_GLOBAL(power7_wakeup_tb_loss) + ld r2,PACATOC(r13); + ld r1,PACAR1(r13) + /* + * Before entering any idle state, the NVGPRs are saved in the stack + * and they are restored before switching to the process context. Hence + * until they are restored, they are free to be used. + * + * Save SRR1 in a NVGPR as it might be clobbered in opal_call_realmode + * (called in CHECK_HMI_INTERRUPT). SRR1 is required to determine the + * wakeup reason if we branch to kvm_start_guest. + */ + + mfspr r16,SPRN_SRR1 +BEGIN_FTR_SECTION + CHECK_HMI_INTERRUPT +END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) + + lbz r7,PACA_THREAD_MASK(r13) + ld r14,PACA_CORE_IDLE_STATE_PTR(r13) +lwarx_loop2: + lwarx r15,0,r14 + andi. r9,r15,PNV_CORE_IDLE_LOCK_BIT + /* + * Lock bit is set in one of the 2 cases- + * a. In the sleep/winkle enter path, the last thread is executing + * fastsleep workaround code. + * b. In the wake up path, another thread is executing fastsleep + * workaround undo code or resyncing timebase or restoring context + * In either case loop until the lock bit is cleared. + */ + bne core_idle_lock_held + + cmpwi cr2,r15,0 + lbz r4,PACA_SUBCORE_SIBLING_MASK(r13) + and r4,r4,r15 + cmpwi cr1,r4,0 /* Check if first in subcore */ + + /* + * At this stage + * cr1 - 0b0100 if first thread to wakeup in subcore + * cr2 - 0b0100 if first thread to wakeup in core + * cr3- 0b0010 if waking up from sleep or winkle + * cr4 - 0b0100 if waking up from winkle + */ + + or r15,r15,r7 /* Set thread bit */ + + beq cr1,first_thread_in_subcore + + /* Not first thread in subcore to wake up */ + stwcx. r15,0,r14 + bne- lwarx_loop2 + isync + b common_exit + +core_idle_lock_held: + HMT_LOW +core_idle_lock_loop: + lwz r15,0(14) + andi. r9,r15,PNV_CORE_IDLE_LOCK_BIT + bne core_idle_lock_loop + HMT_MEDIUM + b lwarx_loop2 + +first_thread_in_subcore: + /* First thread in subcore to wakeup */ + ori r15,r15,PNV_CORE_IDLE_LOCK_BIT + stwcx. r15,0,r14 + bne- lwarx_loop2 + isync + + /* + * If waking up from sleep, subcore state is not lost. Hence + * skip subcore state restore + */ + bne cr4,subcore_state_restored + + /* Restore per-subcore state */ + ld r4,_SDR1(r1) + mtspr SPRN_SDR1,r4 + ld r4,_RPR(r1) + mtspr SPRN_RPR,r4 + ld r4,_AMOR(r1) + mtspr SPRN_AMOR,r4 + +subcore_state_restored: + /* + * Check if the thread is also the first thread in the core. If not, + * skip to clear_lock. + */ + bne cr2,clear_lock + +first_thread_in_core: + + /* + * First thread in the core waking up from fastsleep. It needs to + * call the fastsleep workaround code if the platform requires it. + * Call it unconditionally here. The below branch instruction will + * be patched out when the idle states are discovered if platform + * does not require workaround. + */ +.global pnv_fastsleep_workaround_at_exit +pnv_fastsleep_workaround_at_exit: + b fastsleep_workaround_at_exit + +timebase_resync: + /* Do timebase resync if we are waking up from sleep. Use cr3 value + * set in exceptions-64s.S */ + ble cr3,clear_lock + /* Time base re-sync */ + li r0,OPAL_RESYNC_TIMEBASE + bl opal_call_realmode; + /* TODO: Check r3 for failure */ + + /* + * If waking up from sleep, per core state is not lost, skip to + * clear_lock. + */ + bne cr4,clear_lock + + /* Restore per core state */ + ld r4,_TSCR(r1) + mtspr SPRN_TSCR,r4 + ld r4,_WORC(r1) + mtspr SPRN_WORC,r4 + +clear_lock: + andi. r15,r15,PNV_CORE_IDLE_THREAD_BITS + lwsync + stw r15,0(r14) + +common_exit: + /* + * Common to all threads. + * + * If waking up from sleep, hypervisor state is not lost. Hence + * skip hypervisor state restore. + */ + bne cr4,hypervisor_state_restored + + /* Waking up from winkle */ + + /* Restore per thread state */ + bl __restore_cpu_power8 + + /* Restore SLB from PACA */ + ld r8,PACA_SLBSHADOWPTR(r13) + + .rept SLB_NUM_BOLTED + li r3, SLBSHADOW_SAVEAREA + LDX_BE r5, r8, r3 + addi r3, r3, 8 + LDX_BE r6, r8, r3 + andis. r7,r5,SLB_ESID_V@h + beq 1f + slbmte r6,r5 +1: addi r8,r8,16 + .endr + + ld r4,_SPURR(r1) + mtspr SPRN_SPURR,r4 + ld r4,_PURR(r1) + mtspr SPRN_PURR,r4 + ld r4,_DSCR(r1) + mtspr SPRN_DSCR,r4 + ld r4,_WORT(r1) + mtspr SPRN_WORT,r4 + +hypervisor_state_restored: + + li r5,PNV_THREAD_RUNNING + stb r5,PACA_THREAD_IDLE_STATE(r13) + + mtspr SPRN_SRR1,r16 +#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 6f + b kvm_start_guest +6: +#endif + + REST_NVGPRS(r1) + REST_GPR(2, r1) + ld r3,_CCR(r1) + ld r4,_MSR(r1) + ld r5,_NIP(r1) + addi r1,r1,INT_FRAME_SIZE + mtcr r3 + mfspr r3,SPRN_SRR1 /* Return SRR1 */ + mtspr SPRN_SRR1,r4 + mtspr SPRN_SRR0,r5 + rfid + +fastsleep_workaround_at_exit: + li r3,1 + li r4,0 + li r0,OPAL_CONFIG_CPU_IDLE_STATE + bl opal_call_realmode + b timebase_resync + +/* + * R3 here contains the value that will be returned to the caller + * of power7_nap. + */ +_GLOBAL(power7_wakeup_loss) + ld r1,PACAR1(r13) +BEGIN_FTR_SECTION + CHECK_HMI_INTERRUPT +END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) + REST_NVGPRS(r1) + REST_GPR(2, r1) + ld r6,_CCR(r1) + ld r4,_MSR(r1) + ld r5,_NIP(r1) + addi r1,r1,INT_FRAME_SIZE + mtcr r6 + mtspr SPRN_SRR1,r4 + mtspr SPRN_SRR0,r5 + rfid + +/* + * R3 here contains the value that will be returned to the caller + * of power7_nap. + */ +_GLOBAL(power7_wakeup_noloss) + lbz r0,PACA_NAPSTATELOST(r13) + cmpwi r0,0 + bne power7_wakeup_loss +BEGIN_FTR_SECTION + CHECK_HMI_INTERRUPT +END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) + ld r1,PACAR1(r13) + ld r6,_CCR(r1) + ld r4,_MSR(r1) + ld r5,_NIP(r1) + addi r1,r1,INT_FRAME_SIZE + mtcr r6 + mtspr SPRN_SRR1,r4 + mtspr SPRN_SRR0,r5 + rfid |