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linux/arch/powerpc/platforms/powernv/idle.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PowerNV cpuidle code
*
* Copyright 2015 IBM Corp.
*/
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <asm/asm-prototypes.h>
#include <asm/firmware.h>
#include <asm/machdep.h>
#include <asm/opal.h>
#include <asm/cputhreads.h>
#include <asm/cpuidle.h>
#include <asm/code-patching.h>
#include <asm/smp.h>
#include <asm/runlatch.h>
#include <asm/dbell.h>
#include "powernv.h"
#include "subcore.h"
/* Power ISA 3.0 allows for stop states 0x0 - 0xF */
#define MAX_STOP_STATE 0xF
#define P9_STOP_SPR_MSR 2000
#define P9_STOP_SPR_PSSCR 855
static u32 supported_cpuidle_states;
struct pnv_idle_states_t *pnv_idle_states;
int nr_pnv_idle_states;
/*
* The default stop state that will be used by ppc_md.power_save
* function on platforms that support stop instruction.
*/
static u64 pnv_default_stop_val;
static u64 pnv_default_stop_mask;
static bool default_stop_found;
/*
* First stop state levels when SPR and TB loss can occur.
*/
static u64 pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
static u64 pnv_first_spr_loss_level = MAX_STOP_STATE + 1;
/*
* psscr value and mask of the deepest stop idle state.
* Used when a cpu is offlined.
*/
static u64 pnv_deepest_stop_psscr_val;
static u64 pnv_deepest_stop_psscr_mask;
static u64 pnv_deepest_stop_flag;
static bool deepest_stop_found;
static unsigned long power7_offline_type;
static int pnv_save_sprs_for_deep_states(void)
{
int cpu;
int rc;
/*
* hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric across
* all cpus at boot. Get these reg values of current cpu and use the
* same across all cpus.
*/
uint64_t lpcr_val = mfspr(SPRN_LPCR);
uint64_t hid0_val = mfspr(SPRN_HID0);
uint64_t hid1_val = mfspr(SPRN_HID1);
uint64_t hid4_val = mfspr(SPRN_HID4);
uint64_t hid5_val = mfspr(SPRN_HID5);
uint64_t hmeer_val = mfspr(SPRN_HMEER);
uint64_t msr_val = MSR_IDLE;
uint64_t psscr_val = pnv_deepest_stop_psscr_val;
for_each_present_cpu(cpu) {
uint64_t pir = get_hard_smp_processor_id(cpu);
uint64_t hsprg0_val = (uint64_t)paca_ptrs[cpu];
rc = opal_slw_set_reg(pir, SPRN_HSPRG0, hsprg0_val);
if (rc != 0)
return rc;
rc = opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
if (rc != 0)
return rc;
if (cpu_has_feature(CPU_FTR_ARCH_300)) {
rc = opal_slw_set_reg(pir, P9_STOP_SPR_MSR, msr_val);
if (rc)
return rc;
rc = opal_slw_set_reg(pir,
P9_STOP_SPR_PSSCR, psscr_val);
if (rc)
return rc;
}
/* HIDs are per core registers */
if (cpu_thread_in_core(cpu) == 0) {
rc = opal_slw_set_reg(pir, SPRN_HMEER, hmeer_val);
if (rc != 0)
return rc;
rc = opal_slw_set_reg(pir, SPRN_HID0, hid0_val);
if (rc != 0)
return rc;
/* Only p8 needs to set extra HID regiters */
if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val);
if (rc != 0)
return rc;
rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val);
if (rc != 0)
return rc;
rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val);
if (rc != 0)
return rc;
}
}
}
return 0;
}
u32 pnv_get_supported_cpuidle_states(void)
{
return supported_cpuidle_states;
}
EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states);
static void pnv_fastsleep_workaround_apply(void *info)
{
int rc;
int *err = info;
rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP,
OPAL_CONFIG_IDLE_APPLY);
if (rc)
*err = 1;
}
static bool power7_fastsleep_workaround_entry = true;
static bool power7_fastsleep_workaround_exit = true;
/*
* Used to store fastsleep workaround state
* 0 - Workaround applied/undone at fastsleep entry/exit path (Default)
* 1 - Workaround applied once, never undone.
*/
static u8 fastsleep_workaround_applyonce;
static ssize_t show_fastsleep_workaround_applyonce(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", fastsleep_workaround_applyonce);
}
static ssize_t store_fastsleep_workaround_applyonce(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t count)
{
cpumask_t primary_thread_mask;
int err;
u8 val;
if (kstrtou8(buf, 0, &val) || val != 1)
return -EINVAL;
if (fastsleep_workaround_applyonce == 1)
return count;
/*
* fastsleep_workaround_applyonce = 1 implies
* fastsleep workaround needs to be left in 'applied' state on all
* the cores. Do this by-
* 1. Disable the 'undo' workaround in fastsleep exit path
* 2. Sendi IPIs to all the cores which have at least one online thread
* 3. Disable the 'apply' workaround in fastsleep entry path
*
* There is no need to send ipi to cores which have all threads
* offlined, as last thread of the core entering fastsleep or deeper
* state would have applied workaround.
*/
power7_fastsleep_workaround_exit = false;
get_online_cpus();
primary_thread_mask = cpu_online_cores_map();
on_each_cpu_mask(&primary_thread_mask,
pnv_fastsleep_workaround_apply,
&err, 1);
put_online_cpus();
if (err) {
pr_err("fastsleep_workaround_applyonce change failed while running pnv_fastsleep_workaround_apply");
goto fail;
}
power7_fastsleep_workaround_entry = false;
fastsleep_workaround_applyonce = 1;
return count;
fail:
return -EIO;
}
static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600,
show_fastsleep_workaround_applyonce,
store_fastsleep_workaround_applyonce);
static inline void atomic_start_thread_idle(void)
{
int cpu = raw_smp_processor_id();
int first = cpu_first_thread_sibling(cpu);
int thread_nr = cpu_thread_in_core(cpu);
unsigned long *state = &paca_ptrs[first]->idle_state;
clear_bit(thread_nr, state);
}
static inline void atomic_stop_thread_idle(void)
{
int cpu = raw_smp_processor_id();
int first = cpu_first_thread_sibling(cpu);
int thread_nr = cpu_thread_in_core(cpu);
unsigned long *state = &paca_ptrs[first]->idle_state;
set_bit(thread_nr, state);
}
static inline void atomic_lock_thread_idle(void)
{
int cpu = raw_smp_processor_id();
int first = cpu_first_thread_sibling(cpu);
unsigned long *state = &paca_ptrs[first]->idle_state;
while (unlikely(test_and_set_bit_lock(NR_PNV_CORE_IDLE_LOCK_BIT, state)))
barrier();
}
static inline void atomic_unlock_and_stop_thread_idle(void)
{
int cpu = raw_smp_processor_id();
int first = cpu_first_thread_sibling(cpu);
unsigned long thread = 1UL << cpu_thread_in_core(cpu);
unsigned long *state = &paca_ptrs[first]->idle_state;
u64 s = READ_ONCE(*state);
u64 new, tmp;
BUG_ON(!(s & PNV_CORE_IDLE_LOCK_BIT));
BUG_ON(s & thread);
again:
new = (s | thread) & ~PNV_CORE_IDLE_LOCK_BIT;
tmp = cmpxchg(state, s, new);
if (unlikely(tmp != s)) {
s = tmp;
goto again;
}
}
static inline void atomic_unlock_thread_idle(void)
{
int cpu = raw_smp_processor_id();
int first = cpu_first_thread_sibling(cpu);
unsigned long *state = &paca_ptrs[first]->idle_state;
BUG_ON(!test_bit(NR_PNV_CORE_IDLE_LOCK_BIT, state));
clear_bit_unlock(NR_PNV_CORE_IDLE_LOCK_BIT, state);
}
/* P7 and P8 */
struct p7_sprs {
/* per core */
u64 tscr;
u64 worc;
/* per subcore */
u64 sdr1;
u64 rpr;
/* per thread */
u64 lpcr;
u64 hfscr;
u64 fscr;
u64 purr;
u64 spurr;
u64 dscr;
u64 wort;
/* per thread SPRs that get lost in shallow states */
u64 amr;
u64 iamr;
u64 amor;
u64 uamor;
};
static unsigned long power7_idle_insn(unsigned long type)
{
int cpu = raw_smp_processor_id();
int first = cpu_first_thread_sibling(cpu);
unsigned long *state = &paca_ptrs[first]->idle_state;
unsigned long thread = 1UL << cpu_thread_in_core(cpu);
unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
unsigned long srr1;
bool full_winkle;
struct p7_sprs sprs = {}; /* avoid false use-uninitialised */
bool sprs_saved = false;
int rc;
if (unlikely(type != PNV_THREAD_NAP)) {
atomic_lock_thread_idle();
BUG_ON(!(*state & thread));
*state &= ~thread;
if (power7_fastsleep_workaround_entry) {
if ((*state & core_thread_mask) == 0) {
rc = opal_config_cpu_idle_state(
OPAL_CONFIG_IDLE_FASTSLEEP,
OPAL_CONFIG_IDLE_APPLY);
BUG_ON(rc);
}
}
if (type == PNV_THREAD_WINKLE) {
sprs.tscr = mfspr(SPRN_TSCR);
sprs.worc = mfspr(SPRN_WORC);
sprs.sdr1 = mfspr(SPRN_SDR1);
sprs.rpr = mfspr(SPRN_RPR);
sprs.lpcr = mfspr(SPRN_LPCR);
if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
sprs.hfscr = mfspr(SPRN_HFSCR);
sprs.fscr = mfspr(SPRN_FSCR);
}
sprs.purr = mfspr(SPRN_PURR);
sprs.spurr = mfspr(SPRN_SPURR);
sprs.dscr = mfspr(SPRN_DSCR);
sprs.wort = mfspr(SPRN_WORT);
sprs_saved = true;
/*
* Increment winkle counter and set all winkle bits if
* all threads are winkling. This allows wakeup side to
* distinguish between fast sleep and winkle state
* loss. Fast sleep still has to resync the timebase so
* this may not be a really big win.
*/
*state += 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
if ((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS)
>> PNV_CORE_IDLE_WINKLE_COUNT_SHIFT
== threads_per_core)
*state |= PNV_CORE_IDLE_THREAD_WINKLE_BITS;
WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
}
atomic_unlock_thread_idle();
}
if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
sprs.amr = mfspr(SPRN_AMR);
sprs.iamr = mfspr(SPRN_IAMR);
sprs.amor = mfspr(SPRN_AMOR);
sprs.uamor = mfspr(SPRN_UAMOR);
}
local_paca->thread_idle_state = type;
srr1 = isa206_idle_insn_mayloss(type); /* go idle */
local_paca->thread_idle_state = PNV_THREAD_RUNNING;
WARN_ON_ONCE(!srr1);
WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));
if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
if ((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS) {
/*
* We don't need an isync after the mtsprs here because
* the upcoming mtmsrd is execution synchronizing.
*/
mtspr(SPRN_AMR, sprs.amr);
mtspr(SPRN_IAMR, sprs.iamr);
mtspr(SPRN_AMOR, sprs.amor);
mtspr(SPRN_UAMOR, sprs.uamor);
}
}
if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
hmi_exception_realmode(NULL);
if (likely((srr1 & SRR1_WAKESTATE) != SRR1_WS_HVLOSS)) {
if (unlikely(type != PNV_THREAD_NAP)) {
atomic_lock_thread_idle();
if (type == PNV_THREAD_WINKLE) {
WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
*state -= 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
*state &= ~(thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT);
}
atomic_unlock_and_stop_thread_idle();
}
return srr1;
}
/* HV state loss */
BUG_ON(type == PNV_THREAD_NAP);
atomic_lock_thread_idle();
full_winkle = false;
if (type == PNV_THREAD_WINKLE) {
WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
*state -= 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
if (*state & (thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT)) {
*state &= ~(thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT);
full_winkle = true;
BUG_ON(!sprs_saved);
}
}
WARN_ON(*state & thread);
if ((*state & core_thread_mask) != 0)
goto core_woken;
/* Per-core SPRs */
if (full_winkle) {
mtspr(SPRN_TSCR, sprs.tscr);
mtspr(SPRN_WORC, sprs.worc);
}
if (power7_fastsleep_workaround_exit) {
rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP,
OPAL_CONFIG_IDLE_UNDO);
BUG_ON(rc);
}
/* TB */
if (opal_resync_timebase() != OPAL_SUCCESS)
BUG();
core_woken:
if (!full_winkle)
goto subcore_woken;
if ((*state & local_paca->subcore_sibling_mask) != 0)
goto subcore_woken;
/* Per-subcore SPRs */
mtspr(SPRN_SDR1, sprs.sdr1);
mtspr(SPRN_RPR, sprs.rpr);
subcore_woken:
/*
* isync after restoring shared SPRs and before unlocking. Unlock
* only contains hwsync which does not necessarily do the right
* thing for SPRs.
*/
isync();
atomic_unlock_and_stop_thread_idle();
/* Fast sleep does not lose SPRs */
if (!full_winkle)
return srr1;
/* Per-thread SPRs */
mtspr(SPRN_LPCR, sprs.lpcr);
if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
mtspr(SPRN_HFSCR, sprs.hfscr);
mtspr(SPRN_FSCR, sprs.fscr);
}
mtspr(SPRN_PURR, sprs.purr);
mtspr(SPRN_SPURR, sprs.spurr);
mtspr(SPRN_DSCR, sprs.dscr);
mtspr(SPRN_WORT, sprs.wort);
mtspr(SPRN_SPRG3, local_paca->sprg_vdso);
/*
* The SLB has to be restored here, but it sometimes still
* contains entries, so the __ variant must be used to prevent
* multi hits.
*/
__slb_restore_bolted_realmode();
return srr1;
}
extern unsigned long idle_kvm_start_guest(unsigned long srr1);
#ifdef CONFIG_HOTPLUG_CPU
static unsigned long power7_offline(void)
{
unsigned long srr1;
mtmsr(MSR_IDLE);
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/* Tell KVM we're entering idle. */
/******************************************************/
/* N O T E W E L L ! ! ! N O T E W E L L */
/* The following store to HSTATE_HWTHREAD_STATE(r13) */
/* MUST occur in real mode, i.e. with the MMU off, */
/* and the MMU must stay off until we clear this flag */
/* and test HSTATE_HWTHREAD_REQ(r13) in */
/* pnv_powersave_wakeup in this file. */
/* The reason is that another thread can switch the */
/* MMU to a guest context whenever this flag is set */
/* to KVM_HWTHREAD_IN_IDLE, and if the MMU was on, */
/* that would potentially cause this thread to start */
/* executing instructions from guest memory in */
/* hypervisor mode, leading to a host crash or data */
/* corruption, or worse. */
/******************************************************/
local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_IDLE;
#endif
__ppc64_runlatch_off();
srr1 = power7_idle_insn(power7_offline_type);
__ppc64_runlatch_on();
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_KERNEL;
/* Order setting hwthread_state vs. testing hwthread_req */
smp_mb();
if (local_paca->kvm_hstate.hwthread_req)
srr1 = idle_kvm_start_guest(srr1);
#endif
mtmsr(MSR_KERNEL);
return srr1;
}
#endif
void power7_idle_type(unsigned long type)
{
unsigned long srr1;
if (!prep_irq_for_idle_irqsoff())
return;
mtmsr(MSR_IDLE);
__ppc64_runlatch_off();
srr1 = power7_idle_insn(type);
__ppc64_runlatch_on();
mtmsr(MSR_KERNEL);
fini_irq_for_idle_irqsoff();
irq_set_pending_from_srr1(srr1);
}
void power7_idle(void)
{
if (!powersave_nap)
return;
power7_idle_type(PNV_THREAD_NAP);
}
struct p9_sprs {
/* per core */
u64 ptcr;
u64 rpr;
u64 tscr;
u64 ldbar;
/* per thread */
u64 lpcr;
u64 hfscr;
u64 fscr;
u64 pid;
u64 purr;
u64 spurr;
u64 dscr;
u64 wort;
u64 mmcra;
u32 mmcr0;
u32 mmcr1;
u64 mmcr2;
/* per thread SPRs that get lost in shallow states */
u64 amr;
u64 iamr;
u64 amor;
u64 uamor;
};
static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
{
int cpu = raw_smp_processor_id();
int first = cpu_first_thread_sibling(cpu);
unsigned long *state = &paca_ptrs[first]->idle_state;
unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
unsigned long srr1;
unsigned long pls;
unsigned long mmcr0 = 0;
struct p9_sprs sprs = {}; /* avoid false used-uninitialised */
bool sprs_saved = false;
if (!(psscr & (PSSCR_EC|PSSCR_ESL))) {
/* EC=ESL=0 case */
BUG_ON(!mmu_on);
/*
* Wake synchronously. SRESET via xscom may still cause
* a 0x100 powersave wakeup with SRR1 reason!
*/
srr1 = isa300_idle_stop_noloss(psscr); /* go idle */
if (likely(!srr1))
return 0;
/*
* Registers not saved, can't recover!
* This would be a hardware bug
*/
BUG_ON((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS);
goto out;
}
/* EC=ESL=1 case */
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
if (cpu_has_feature(CPU_FTR_P9_TM_XER_SO_BUG)) {
local_paca->requested_psscr = psscr;
/* order setting requested_psscr vs testing dont_stop */
smp_mb();
if (atomic_read(&local_paca->dont_stop)) {
local_paca->requested_psscr = 0;
return 0;
}
}
#endif
if (!cpu_has_feature(CPU_FTR_POWER9_DD2_1)) {
/*
* POWER9 DD2 can incorrectly set PMAO when waking up
* after a state-loss idle. Saving and restoring MMCR0
* over idle is a workaround.
*/
mmcr0 = mfspr(SPRN_MMCR0);
}
if ((psscr & PSSCR_RL_MASK) >= pnv_first_spr_loss_level) {
sprs.lpcr = mfspr(SPRN_LPCR);
sprs.hfscr = mfspr(SPRN_HFSCR);
sprs.fscr = mfspr(SPRN_FSCR);
sprs.pid = mfspr(SPRN_PID);
sprs.purr = mfspr(SPRN_PURR);
sprs.spurr = mfspr(SPRN_SPURR);
sprs.dscr = mfspr(SPRN_DSCR);
sprs.wort = mfspr(SPRN_WORT);
sprs.mmcra = mfspr(SPRN_MMCRA);
sprs.mmcr0 = mfspr(SPRN_MMCR0);
sprs.mmcr1 = mfspr(SPRN_MMCR1);
sprs.mmcr2 = mfspr(SPRN_MMCR2);
sprs.ptcr = mfspr(SPRN_PTCR);
sprs.rpr = mfspr(SPRN_RPR);
sprs.tscr = mfspr(SPRN_TSCR);
if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
sprs.ldbar = mfspr(SPRN_LDBAR);
sprs_saved = true;
atomic_start_thread_idle();
}
sprs.amr = mfspr(SPRN_AMR);
sprs.iamr = mfspr(SPRN_IAMR);
sprs.amor = mfspr(SPRN_AMOR);
sprs.uamor = mfspr(SPRN_UAMOR);
srr1 = isa300_idle_stop_mayloss(psscr); /* go idle */
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
local_paca->requested_psscr = 0;
#endif
psscr = mfspr(SPRN_PSSCR);
WARN_ON_ONCE(!srr1);
WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));
if ((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS) {
unsigned long mmcra;
/*
* We don't need an isync after the mtsprs here because the
* upcoming mtmsrd is execution synchronizing.
*/
mtspr(SPRN_AMR, sprs.amr);
mtspr(SPRN_IAMR, sprs.iamr);
mtspr(SPRN_AMOR, sprs.amor);
mtspr(SPRN_UAMOR, sprs.uamor);
/*
* Workaround for POWER9 DD2.0, if we lost resources, the ERAT
* might have been corrupted and needs flushing. We also need
* to reload MMCR0 (see mmcr0 comment above).
*/
if (!cpu_has_feature(CPU_FTR_POWER9_DD2_1)) {
asm volatile(PPC_ISA_3_0_INVALIDATE_ERAT);
mtspr(SPRN_MMCR0, mmcr0);
}
/*
* DD2.2 and earlier need to set then clear bit 60 in MMCRA
* to ensure the PMU starts running.
*/
mmcra = mfspr(SPRN_MMCRA);
mmcra |= PPC_BIT(60);
mtspr(SPRN_MMCRA, mmcra);
mmcra &= ~PPC_BIT(60);
mtspr(SPRN_MMCRA, mmcra);
}
if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
hmi_exception_realmode(NULL);
/*
* On POWER9, SRR1 bits do not match exactly as expected.
* SRR1_WS_GPRLOSS (10b) can also result in SPR loss, so
* just always test PSSCR for SPR/TB state loss.
*/
pls = (psscr & PSSCR_PLS) >> PSSCR_PLS_SHIFT;
if (likely(pls < pnv_first_spr_loss_level)) {
if (sprs_saved)
atomic_stop_thread_idle();
goto out;
}
/* HV state loss */
BUG_ON(!sprs_saved);
atomic_lock_thread_idle();
if ((*state & core_thread_mask) != 0)
goto core_woken;
/* Per-core SPRs */
mtspr(SPRN_PTCR, sprs.ptcr);
mtspr(SPRN_RPR, sprs.rpr);
mtspr(SPRN_TSCR, sprs.tscr);
if (pls >= pnv_first_tb_loss_level) {
/* TB loss */
if (opal_resync_timebase() != OPAL_SUCCESS)
BUG();
}
/*
* isync after restoring shared SPRs and before unlocking. Unlock
* only contains hwsync which does not necessarily do the right
* thing for SPRs.
*/
isync();
core_woken:
atomic_unlock_and_stop_thread_idle();
/* Per-thread SPRs */
mtspr(SPRN_LPCR, sprs.lpcr);
mtspr(SPRN_HFSCR, sprs.hfscr);
mtspr(SPRN_FSCR, sprs.fscr);
mtspr(SPRN_PID, sprs.pid);
mtspr(SPRN_PURR, sprs.purr);
mtspr(SPRN_SPURR, sprs.spurr);
mtspr(SPRN_DSCR, sprs.dscr);
mtspr(SPRN_WORT, sprs.wort);
mtspr(SPRN_MMCRA, sprs.mmcra);
mtspr(SPRN_MMCR0, sprs.mmcr0);
mtspr(SPRN_MMCR1, sprs.mmcr1);
mtspr(SPRN_MMCR2, sprs.mmcr2);
if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
mtspr(SPRN_LDBAR, sprs.ldbar);
mtspr(SPRN_SPRG3, local_paca->sprg_vdso);
if (!radix_enabled())
__slb_restore_bolted_realmode();
out:
if (mmu_on)
mtmsr(MSR_KERNEL);
return srr1;
}
#ifdef CONFIG_HOTPLUG_CPU
static unsigned long power9_offline_stop(unsigned long psscr)
{
unsigned long srr1;
#ifndef CONFIG_KVM_BOOK3S_HV_POSSIBLE
__ppc64_runlatch_off();
srr1 = power9_idle_stop(psscr, true);
__ppc64_runlatch_on();
#else
/*
* Tell KVM we're entering idle.
* This does not have to be done in real mode because the P9 MMU
* is independent per-thread. Some steppings share radix/hash mode
* between threads, but in that case KVM has a barrier sync in real
* mode before and after switching between radix and hash.
*
* kvm_start_guest must still be called in real mode though, hence
* the false argument.
*/
local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_IDLE;
__ppc64_runlatch_off();
srr1 = power9_idle_stop(psscr, false);
__ppc64_runlatch_on();
local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_KERNEL;
/* Order setting hwthread_state vs. testing hwthread_req */
smp_mb();
if (local_paca->kvm_hstate.hwthread_req)
srr1 = idle_kvm_start_guest(srr1);
mtmsr(MSR_KERNEL);
#endif
return srr1;
}
#endif
void power9_idle_type(unsigned long stop_psscr_val,
unsigned long stop_psscr_mask)
{
unsigned long psscr;
unsigned long srr1;
if (!prep_irq_for_idle_irqsoff())
return;
psscr = mfspr(SPRN_PSSCR);
psscr = (psscr & ~stop_psscr_mask) | stop_psscr_val;
__ppc64_runlatch_off();
srr1 = power9_idle_stop(psscr, true);
__ppc64_runlatch_on();
fini_irq_for_idle_irqsoff();
irq_set_pending_from_srr1(srr1);
}
/*
* Used for ppc_md.power_save which needs a function with no parameters
*/
void power9_idle(void)
{
power9_idle_type(pnv_default_stop_val, pnv_default_stop_mask);
}
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
/*
* This is used in working around bugs in thread reconfiguration
* on POWER9 (at least up to Nimbus DD2.2) relating to transactional
* memory and the way that XER[SO] is checkpointed.
* This function forces the core into SMT4 in order by asking
* all other threads not to stop, and sending a message to any
* that are in a stop state.
* Must be called with preemption disabled.
*/
void pnv_power9_force_smt4_catch(void)
{
int cpu, cpu0, thr;
int awake_threads = 1; /* this thread is awake */
int poke_threads = 0;
int need_awake = threads_per_core;
cpu = smp_processor_id();
cpu0 = cpu & ~(threads_per_core - 1);
for (thr = 0; thr < threads_per_core; ++thr) {
if (cpu != cpu0 + thr)
atomic_inc(&paca_ptrs[cpu0+thr]->dont_stop);
}
/* order setting dont_stop vs testing requested_psscr */
smp_mb();
for (thr = 0; thr < threads_per_core; ++thr) {
if (!paca_ptrs[cpu0+thr]->requested_psscr)
++awake_threads;
else
poke_threads |= (1 << thr);
}
/* If at least 3 threads are awake, the core is in SMT4 already */
if (awake_threads < need_awake) {
/* We have to wake some threads; we'll use msgsnd */
for (thr = 0; thr < threads_per_core; ++thr) {
if (poke_threads & (1 << thr)) {
ppc_msgsnd_sync();
ppc_msgsnd(PPC_DBELL_MSGTYPE, 0,
paca_ptrs[cpu0+thr]->hw_cpu_id);
}
}
/* now spin until at least 3 threads are awake */
do {
for (thr = 0; thr < threads_per_core; ++thr) {
if ((poke_threads & (1 << thr)) &&
!paca_ptrs[cpu0+thr]->requested_psscr) {
++awake_threads;
poke_threads &= ~(1 << thr);
}
}
} while (awake_threads < need_awake);
}
}
EXPORT_SYMBOL_GPL(pnv_power9_force_smt4_catch);
void pnv_power9_force_smt4_release(void)
{
int cpu, cpu0, thr;
cpu = smp_processor_id();
cpu0 = cpu & ~(threads_per_core - 1);
/* clear all the dont_stop flags */
for (thr = 0; thr < threads_per_core; ++thr) {
if (cpu != cpu0 + thr)
atomic_dec(&paca_ptrs[cpu0+thr]->dont_stop);
}
}
EXPORT_SYMBOL_GPL(pnv_power9_force_smt4_release);
#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
#ifdef CONFIG_HOTPLUG_CPU
void pnv_program_cpu_hotplug_lpcr(unsigned int cpu, u64 lpcr_val)
{
u64 pir = get_hard_smp_processor_id(cpu);
mtspr(SPRN_LPCR, lpcr_val);
/*
* Program the LPCR via stop-api only if the deepest stop state
* can lose hypervisor context.
*/
if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT)
opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
}
/*
* pnv_cpu_offline: A function that puts the CPU into the deepest
* available platform idle state on a CPU-Offline.
* interrupts hard disabled and no lazy irq pending.
*/
unsigned long pnv_cpu_offline(unsigned int cpu)
{
unsigned long srr1;
__ppc64_runlatch_off();
if (cpu_has_feature(CPU_FTR_ARCH_300) && deepest_stop_found) {
unsigned long psscr;
psscr = mfspr(SPRN_PSSCR);
psscr = (psscr & ~pnv_deepest_stop_psscr_mask) |
pnv_deepest_stop_psscr_val;
srr1 = power9_offline_stop(psscr);
} else if (cpu_has_feature(CPU_FTR_ARCH_206) && power7_offline_type) {
srr1 = power7_offline();
} else {
/* This is the fallback method. We emulate snooze */
while (!generic_check_cpu_restart(cpu)) {
HMT_low();
HMT_very_low();
}
srr1 = 0;
HMT_medium();
}
__ppc64_runlatch_on();
return srr1;
}
#endif
/*
* Power ISA 3.0 idle initialization.
*
* POWER ISA 3.0 defines a new SPR Processor stop Status and Control
* Register (PSSCR) to control idle behavior.
*
* PSSCR layout:
* ----------------------------------------------------------
* | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL |
* ----------------------------------------------------------
* 0 4 41 42 43 44 48 54 56 60
*
* PSSCR key fields:
* Bits 0:3 - Power-Saving Level Status (PLS). This field indicates the
* lowest power-saving state the thread entered since stop instruction was
* last executed.
*
* Bit 41 - Status Disable(SD)
* 0 - Shows PLS entries
* 1 - PLS entries are all 0
*
* Bit 42 - Enable State Loss
* 0 - No state is lost irrespective of other fields
* 1 - Allows state loss
*
* Bit 43 - Exit Criterion
* 0 - Exit from power-save mode on any interrupt
* 1 - Exit from power-save mode controlled by LPCR's PECE bits
*
* Bits 44:47 - Power-Saving Level Limit
* This limits the power-saving level that can be entered into.
*
* Bits 60:63 - Requested Level
* Used to specify which power-saving level must be entered on executing
* stop instruction
*/
int validate_psscr_val_mask(u64 *psscr_val, u64 *psscr_mask, u32 flags)
{
int err = 0;
/*
* psscr_mask == 0xf indicates an older firmware.
* Set remaining fields of psscr to the default values.
* See NOTE above definition of PSSCR_HV_DEFAULT_VAL
*/
if (*psscr_mask == 0xf) {
*psscr_val = *psscr_val | PSSCR_HV_DEFAULT_VAL;
*psscr_mask = PSSCR_HV_DEFAULT_MASK;
return err;
}
/*
* New firmware is expected to set the psscr_val bits correctly.
* Validate that the following invariants are correctly maintained by
* the new firmware.
* - ESL bit value matches the EC bit value.
* - ESL bit is set for all the deep stop states.
*/
if (GET_PSSCR_ESL(*psscr_val) != GET_PSSCR_EC(*psscr_val)) {
err = ERR_EC_ESL_MISMATCH;
} else if ((flags & OPAL_PM_LOSE_FULL_CONTEXT) &&
GET_PSSCR_ESL(*psscr_val) == 0) {
err = ERR_DEEP_STATE_ESL_MISMATCH;
}
return err;
}
/*
* pnv_arch300_idle_init: Initializes the default idle state, first
* deep idle state and deepest idle state on
* ISA 3.0 CPUs.
*
* @np: /ibm,opal/power-mgt device node
* @flags: cpu-idle-state-flags array
* @dt_idle_states: Number of idle state entries
* Returns 0 on success
*/
static void __init pnv_power9_idle_init(void)
{
u64 max_residency_ns = 0;
int i;
/*
* pnv_deepest_stop_{val,mask} should be set to values corresponding to
* the deepest stop state.
*
* pnv_default_stop_{val,mask} should be set to values corresponding to
* the deepest loss-less (OPAL_PM_STOP_INST_FAST) stop state.
*/
pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
pnv_first_spr_loss_level = MAX_STOP_STATE + 1;
for (i = 0; i < nr_pnv_idle_states; i++) {
int err;
struct pnv_idle_states_t *state = &pnv_idle_states[i];
u64 psscr_rl = state->psscr_val & PSSCR_RL_MASK;
if ((state->flags & OPAL_PM_TIMEBASE_STOP) &&
(pnv_first_tb_loss_level > psscr_rl))
pnv_first_tb_loss_level = psscr_rl;
if ((state->flags & OPAL_PM_LOSE_FULL_CONTEXT) &&
(pnv_first_spr_loss_level > psscr_rl))
pnv_first_spr_loss_level = psscr_rl;
/*
* The idle code does not deal with TB loss occurring
* in a shallower state than SPR loss, so force it to
* behave like SPRs are lost if TB is lost. POWER9 would
* never encouter this, but a POWER8 core would if it
* implemented the stop instruction. So this is for forward
* compatibility.
*/
if ((state->flags & OPAL_PM_TIMEBASE_STOP) &&
(pnv_first_spr_loss_level > psscr_rl))
pnv_first_spr_loss_level = psscr_rl;
err = validate_psscr_val_mask(&state->psscr_val,
&state->psscr_mask,
state->flags);
if (err) {
report_invalid_psscr_val(state->psscr_val, err);
continue;
}
state->valid = true;
if (max_residency_ns < state->residency_ns) {
max_residency_ns = state->residency_ns;
pnv_deepest_stop_psscr_val = state->psscr_val;
pnv_deepest_stop_psscr_mask = state->psscr_mask;
pnv_deepest_stop_flag = state->flags;
deepest_stop_found = true;
}
if (!default_stop_found &&
(state->flags & OPAL_PM_STOP_INST_FAST)) {
pnv_default_stop_val = state->psscr_val;
pnv_default_stop_mask = state->psscr_mask;
default_stop_found = true;
WARN_ON(state->flags & OPAL_PM_LOSE_FULL_CONTEXT);
}
}
if (unlikely(!default_stop_found)) {
pr_warn("cpuidle-powernv: No suitable default stop state found. Disabling platform idle.\n");
} else {
ppc_md.power_save = power9_idle;
pr_info("cpuidle-powernv: Default stop: psscr = 0x%016llx,mask=0x%016llx\n",
pnv_default_stop_val, pnv_default_stop_mask);
}
if (unlikely(!deepest_stop_found)) {
pr_warn("cpuidle-powernv: No suitable stop state for CPU-Hotplug. Offlined CPUs will busy wait");
} else {
pr_info("cpuidle-powernv: Deepest stop: psscr = 0x%016llx,mask=0x%016llx\n",
pnv_deepest_stop_psscr_val,
pnv_deepest_stop_psscr_mask);
}
pr_info("cpuidle-powernv: First stop level that may lose SPRs = 0x%llx\n",
pnv_first_spr_loss_level);
pr_info("cpuidle-powernv: First stop level that may lose timebase = 0x%llx\n",
pnv_first_tb_loss_level);
}
static void __init pnv_disable_deep_states(void)
{
/*
* The stop-api is unable to restore hypervisor
* resources on wakeup from platform idle states which
* lose full context. So disable such states.
*/
supported_cpuidle_states &= ~OPAL_PM_LOSE_FULL_CONTEXT;
pr_warn("cpuidle-powernv: Disabling idle states that lose full context\n");
pr_warn("cpuidle-powernv: Idle power-savings, CPU-Hotplug affected\n");
if (cpu_has_feature(CPU_FTR_ARCH_300) &&
(pnv_deepest_stop_flag & OPAL_PM_LOSE_FULL_CONTEXT)) {
/*
* Use the default stop state for CPU-Hotplug
* if available.
*/
if (default_stop_found) {
pnv_deepest_stop_psscr_val = pnv_default_stop_val;
pnv_deepest_stop_psscr_mask = pnv_default_stop_mask;
pr_warn("cpuidle-powernv: Offlined CPUs will stop with psscr = 0x%016llx\n",
pnv_deepest_stop_psscr_val);
} else { /* Fallback to snooze loop for CPU-Hotplug */
deepest_stop_found = false;
pr_warn("cpuidle-powernv: Offlined CPUs will busy wait\n");
}
}
}
/*
* Probe device tree for supported idle states
*/
static void __init pnv_probe_idle_states(void)
{
int i;
if (nr_pnv_idle_states < 0) {
pr_warn("cpuidle-powernv: no idle states found in the DT\n");
return;
}
if (cpu_has_feature(CPU_FTR_ARCH_300))
pnv_power9_idle_init();
for (i = 0; i < nr_pnv_idle_states; i++)
supported_cpuidle_states |= pnv_idle_states[i].flags;
}
/*
* This function parses device-tree and populates all the information
* into pnv_idle_states structure. It also sets up nr_pnv_idle_states
* which is the number of cpuidle states discovered through device-tree.
*/
static int pnv_parse_cpuidle_dt(void)
{
struct device_node *np;
int nr_idle_states, i;
int rc = 0;
u32 *temp_u32;
u64 *temp_u64;
const char **temp_string;
np = of_find_node_by_path("/ibm,opal/power-mgt");
if (!np) {
pr_warn("opal: PowerMgmt Node not found\n");
return -ENODEV;
}
nr_idle_states = of_property_count_u32_elems(np,
"ibm,cpu-idle-state-flags");
pnv_idle_states = kcalloc(nr_idle_states, sizeof(*pnv_idle_states),
GFP_KERNEL);
temp_u32 = kcalloc(nr_idle_states, sizeof(u32), GFP_KERNEL);
temp_u64 = kcalloc(nr_idle_states, sizeof(u64), GFP_KERNEL);
temp_string = kcalloc(nr_idle_states, sizeof(char *), GFP_KERNEL);
if (!(pnv_idle_states && temp_u32 && temp_u64 && temp_string)) {
pr_err("Could not allocate memory for dt parsing\n");
rc = -ENOMEM;
goto out;
}
/* Read flags */
if (of_property_read_u32_array(np, "ibm,cpu-idle-state-flags",
temp_u32, nr_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n");
rc = -EINVAL;
goto out;
}
for (i = 0; i < nr_idle_states; i++)
pnv_idle_states[i].flags = temp_u32[i];
/* Read latencies */
if (of_property_read_u32_array(np, "ibm,cpu-idle-state-latencies-ns",
temp_u32, nr_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
rc = -EINVAL;
goto out;
}
for (i = 0; i < nr_idle_states; i++)
pnv_idle_states[i].latency_ns = temp_u32[i];
/* Read residencies */
if (of_property_read_u32_array(np, "ibm,cpu-idle-state-residency-ns",
temp_u32, nr_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
rc = -EINVAL;
goto out;
}
for (i = 0; i < nr_idle_states; i++)
pnv_idle_states[i].residency_ns = temp_u32[i];
/* For power9 */
if (cpu_has_feature(CPU_FTR_ARCH_300)) {
/* Read pm_crtl_val */
if (of_property_read_u64_array(np, "ibm,cpu-idle-state-psscr",
temp_u64, nr_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
rc = -EINVAL;
goto out;
}
for (i = 0; i < nr_idle_states; i++)
pnv_idle_states[i].psscr_val = temp_u64[i];
/* Read pm_crtl_mask */
if (of_property_read_u64_array(np, "ibm,cpu-idle-state-psscr-mask",
temp_u64, nr_idle_states)) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr-mask in DT\n");
rc = -EINVAL;
goto out;
}
for (i = 0; i < nr_idle_states; i++)
pnv_idle_states[i].psscr_mask = temp_u64[i];
}
/*
* power8 specific properties ibm,cpu-idle-state-pmicr-mask and
* ibm,cpu-idle-state-pmicr-val were never used and there is no
* plan to use it in near future. Hence, not parsing these properties
*/
if (of_property_read_string_array(np, "ibm,cpu-idle-state-names",
temp_string, nr_idle_states) < 0) {
pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
rc = -EINVAL;
goto out;
}
for (i = 0; i < nr_idle_states; i++)
strlcpy(pnv_idle_states[i].name, temp_string[i],
PNV_IDLE_NAME_LEN);
nr_pnv_idle_states = nr_idle_states;
rc = 0;
out:
kfree(temp_u32);
kfree(temp_u64);
kfree(temp_string);
return rc;
}
static int __init pnv_init_idle_states(void)
{
int cpu;
int rc = 0;
/* Set up PACA fields */
for_each_present_cpu(cpu) {
struct paca_struct *p = paca_ptrs[cpu];
p->idle_state = 0;
if (cpu == cpu_first_thread_sibling(cpu))
p->idle_state = (1 << threads_per_core) - 1;
if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
/* P7/P8 nap */
p->thread_idle_state = PNV_THREAD_RUNNING;
} else {
/* P9 stop */
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
p->requested_psscr = 0;
atomic_set(&p->dont_stop, 0);
#endif
}
}
/* In case we error out nr_pnv_idle_states will be zero */
nr_pnv_idle_states = 0;
supported_cpuidle_states = 0;
if (cpuidle_disable != IDLE_NO_OVERRIDE)
goto out;
rc = pnv_parse_cpuidle_dt();
if (rc)
return rc;
pnv_probe_idle_states();
if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
if (!(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
power7_fastsleep_workaround_entry = false;
power7_fastsleep_workaround_exit = false;
} else {
/*
* OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that
* workaround is needed to use fastsleep. Provide sysfs
* control to choose how this workaround has to be
* applied.
*/
device_create_file(cpu_subsys.dev_root,
&dev_attr_fastsleep_workaround_applyonce);
}
update_subcore_sibling_mask();
if (supported_cpuidle_states & OPAL_PM_NAP_ENABLED) {
ppc_md.power_save = power7_idle;
power7_offline_type = PNV_THREAD_NAP;
}
if ((supported_cpuidle_states & OPAL_PM_WINKLE_ENABLED) &&
(supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT))
power7_offline_type = PNV_THREAD_WINKLE;
else if ((supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED) ||
(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1))
power7_offline_type = PNV_THREAD_SLEEP;
}
if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) {
if (pnv_save_sprs_for_deep_states())
pnv_disable_deep_states();
}
out:
return 0;
}
machine_subsys_initcall(powernv, pnv_init_idle_states);
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