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linux/arch/powerpc/kernel/smp.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* SMP support for ppc.
*
* Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
* deal of code from the sparc and intel versions.
*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*
* PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
* Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
*/
#undef DEBUG
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/sched/mm.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/topology.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/topology.h>
#include <linux/profile.h>
#include <linux/processor.h>
#include <linux/random.h>
#include <linux/stackprotector.h>
#include <asm/ptrace.h>
#include <linux/atomic.h>
#include <asm/irq.h>
#include <asm/hw_irq.h>
#include <asm/kvm_ppc.h>
#include <asm/dbell.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputhreads.h>
#include <asm/cputable.h>
#include <asm/mpic.h>
#include <asm/vdso_datapage.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#endif
#include <asm/vdso.h>
#include <asm/debug.h>
#include <asm/kexec.h>
#include <asm/asm-prototypes.h>
#include <asm/cpu_has_feature.h>
#include <asm/ftrace.h>
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
#ifdef CONFIG_HOTPLUG_CPU
/* State of each CPU during hotplug phases */
static DEFINE_PER_CPU(int, cpu_state) = { 0 };
#endif
struct task_struct *secondary_current;
bool has_big_cores;
DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
DEFINE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);
EXPORT_SYMBOL_GPL(has_big_cores);
#define MAX_THREAD_LIST_SIZE 8
#define THREAD_GROUP_SHARE_L1 1
struct thread_groups {
unsigned int property;
unsigned int nr_groups;
unsigned int threads_per_group;
unsigned int thread_list[MAX_THREAD_LIST_SIZE];
};
/*
* On big-cores system, cpu_l1_cache_map for each CPU corresponds to
* the set its siblings that share the L1-cache.
*/
DEFINE_PER_CPU(cpumask_var_t, cpu_l1_cache_map);
/* SMP operations for this machine */
struct smp_ops_t *smp_ops;
/* Can't be static due to PowerMac hackery */
volatile unsigned int cpu_callin_map[NR_CPUS];
int smt_enabled_at_boot = 1;
/*
* Returns 1 if the specified cpu should be brought up during boot.
* Used to inhibit booting threads if they've been disabled or
* limited on the command line
*/
int smp_generic_cpu_bootable(unsigned int nr)
{
/* Special case - we inhibit secondary thread startup
* during boot if the user requests it.
*/
if (system_state < SYSTEM_RUNNING && cpu_has_feature(CPU_FTR_SMT)) {
if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
return 0;
if (smt_enabled_at_boot
&& cpu_thread_in_core(nr) >= smt_enabled_at_boot)
return 0;
}
return 1;
}
#ifdef CONFIG_PPC64
int smp_generic_kick_cpu(int nr)
{
if (nr < 0 || nr >= nr_cpu_ids)
return -EINVAL;
/*
* The processor is currently spinning, waiting for the
* cpu_start field to become non-zero After we set cpu_start,
* the processor will continue on to secondary_start
*/
if (!paca_ptrs[nr]->cpu_start) {
paca_ptrs[nr]->cpu_start = 1;
smp_mb();
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
/*
* Ok it's not there, so it might be soft-unplugged, let's
* try to bring it back
*/
generic_set_cpu_up(nr);
smp_wmb();
smp_send_reschedule(nr);
#endif /* CONFIG_HOTPLUG_CPU */
return 0;
}
#endif /* CONFIG_PPC64 */
static irqreturn_t call_function_action(int irq, void *data)
{
generic_smp_call_function_interrupt();
return IRQ_HANDLED;
}
static irqreturn_t reschedule_action(int irq, void *data)
{
scheduler_ipi();
return IRQ_HANDLED;
}
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
static irqreturn_t tick_broadcast_ipi_action(int irq, void *data)
{
timer_broadcast_interrupt();
return IRQ_HANDLED;
}
#endif
#ifdef CONFIG_NMI_IPI
static irqreturn_t nmi_ipi_action(int irq, void *data)
{
smp_handle_nmi_ipi(get_irq_regs());
return IRQ_HANDLED;
}
#endif
static irq_handler_t smp_ipi_action[] = {
[PPC_MSG_CALL_FUNCTION] = call_function_action,
[PPC_MSG_RESCHEDULE] = reschedule_action,
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
[PPC_MSG_TICK_BROADCAST] = tick_broadcast_ipi_action,
#endif
#ifdef CONFIG_NMI_IPI
[PPC_MSG_NMI_IPI] = nmi_ipi_action,
#endif
};
/*
* The NMI IPI is a fallback and not truly non-maskable. It is simpler
* than going through the call function infrastructure, and strongly
* serialized, so it is more appropriate for debugging.
*/
const char *smp_ipi_name[] = {
[PPC_MSG_CALL_FUNCTION] = "ipi call function",
[PPC_MSG_RESCHEDULE] = "ipi reschedule",
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
[PPC_MSG_TICK_BROADCAST] = "ipi tick-broadcast",
#endif
#ifdef CONFIG_NMI_IPI
[PPC_MSG_NMI_IPI] = "nmi ipi",
#endif
};
/* optional function to request ipi, for controllers with >= 4 ipis */
int smp_request_message_ipi(int virq, int msg)
{
int err;
if (msg < 0 || msg > PPC_MSG_NMI_IPI)
return -EINVAL;
#ifndef CONFIG_NMI_IPI
if (msg == PPC_MSG_NMI_IPI)
return 1;
#endif
err = request_irq(virq, smp_ipi_action[msg],
IRQF_PERCPU | IRQF_NO_THREAD | IRQF_NO_SUSPEND,
smp_ipi_name[msg], NULL);
WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
virq, smp_ipi_name[msg], err);
return err;
}
#ifdef CONFIG_PPC_SMP_MUXED_IPI
struct cpu_messages {
long messages; /* current messages */
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_messages, ipi_message);
void smp_muxed_ipi_set_message(int cpu, int msg)
{
struct cpu_messages *info = &per_cpu(ipi_message, cpu);
char *message = (char *)&info->messages;
/*
* Order previous accesses before accesses in the IPI handler.
*/
smp_mb();
message[msg] = 1;
}
void smp_muxed_ipi_message_pass(int cpu, int msg)
{
smp_muxed_ipi_set_message(cpu, msg);
/*
* cause_ipi functions are required to include a full barrier
* before doing whatever causes the IPI.
*/
smp_ops->cause_ipi(cpu);
}
#ifdef __BIG_ENDIAN__
#define IPI_MESSAGE(A) (1uL << ((BITS_PER_LONG - 8) - 8 * (A)))
#else
#define IPI_MESSAGE(A) (1uL << (8 * (A)))
#endif
irqreturn_t smp_ipi_demux(void)
{
mb(); /* order any irq clear */
return smp_ipi_demux_relaxed();
}
/* sync-free variant. Callers should ensure synchronization */
irqreturn_t smp_ipi_demux_relaxed(void)
{
struct cpu_messages *info;
unsigned long all;
info = this_cpu_ptr(&ipi_message);
do {
all = xchg(&info->messages, 0);
#if defined(CONFIG_KVM_XICS) && defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)
/*
* Must check for PPC_MSG_RM_HOST_ACTION messages
* before PPC_MSG_CALL_FUNCTION messages because when
* a VM is destroyed, we call kick_all_cpus_sync()
* to ensure that any pending PPC_MSG_RM_HOST_ACTION
* messages have completed before we free any VCPUs.
*/
if (all & IPI_MESSAGE(PPC_MSG_RM_HOST_ACTION))
kvmppc_xics_ipi_action();
#endif
if (all & IPI_MESSAGE(PPC_MSG_CALL_FUNCTION))
generic_smp_call_function_interrupt();
if (all & IPI_MESSAGE(PPC_MSG_RESCHEDULE))
scheduler_ipi();
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
if (all & IPI_MESSAGE(PPC_MSG_TICK_BROADCAST))
timer_broadcast_interrupt();
#endif
#ifdef CONFIG_NMI_IPI
if (all & IPI_MESSAGE(PPC_MSG_NMI_IPI))
nmi_ipi_action(0, NULL);
#endif
} while (info->messages);
return IRQ_HANDLED;
}
#endif /* CONFIG_PPC_SMP_MUXED_IPI */
static inline void do_message_pass(int cpu, int msg)
{
if (smp_ops->message_pass)
smp_ops->message_pass(cpu, msg);
#ifdef CONFIG_PPC_SMP_MUXED_IPI
else
smp_muxed_ipi_message_pass(cpu, msg);
#endif
}
void smp_send_reschedule(int cpu)
{
if (likely(smp_ops))
do_message_pass(cpu, PPC_MSG_RESCHEDULE);
}
EXPORT_SYMBOL_GPL(smp_send_reschedule);
void arch_send_call_function_single_ipi(int cpu)
{
do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
}
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
unsigned int cpu;
for_each_cpu(cpu, mask)
do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
}
#ifdef CONFIG_NMI_IPI
/*
* "NMI IPI" system.
*
* NMI IPIs may not be recoverable, so should not be used as ongoing part of
* a running system. They can be used for crash, debug, halt/reboot, etc.
*
* The IPI call waits with interrupts disabled until all targets enter the
* NMI handler, then returns. Subsequent IPIs can be issued before targets
* have returned from their handlers, so there is no guarantee about
* concurrency or re-entrancy.
*
* A new NMI can be issued before all targets exit the handler.
*
* The IPI call may time out without all targets entering the NMI handler.
* In that case, there is some logic to recover (and ignore subsequent
* NMI interrupts that may eventually be raised), but the platform interrupt
* handler may not be able to distinguish this from other exception causes,
* which may cause a crash.
*/
static atomic_t __nmi_ipi_lock = ATOMIC_INIT(0);
static struct cpumask nmi_ipi_pending_mask;
static bool nmi_ipi_busy = false;
static void (*nmi_ipi_function)(struct pt_regs *) = NULL;
static void nmi_ipi_lock_start(unsigned long *flags)
{
raw_local_irq_save(*flags);
hard_irq_disable();
while (atomic_cmpxchg(&__nmi_ipi_lock, 0, 1) == 1) {
raw_local_irq_restore(*flags);
spin_until_cond(atomic_read(&__nmi_ipi_lock) == 0);
raw_local_irq_save(*flags);
hard_irq_disable();
}
}
static void nmi_ipi_lock(void)
{
while (atomic_cmpxchg(&__nmi_ipi_lock, 0, 1) == 1)
spin_until_cond(atomic_read(&__nmi_ipi_lock) == 0);
}
static void nmi_ipi_unlock(void)
{
smp_mb();
WARN_ON(atomic_read(&__nmi_ipi_lock) != 1);
atomic_set(&__nmi_ipi_lock, 0);
}
static void nmi_ipi_unlock_end(unsigned long *flags)
{
nmi_ipi_unlock();
raw_local_irq_restore(*flags);
}
/*
* Platform NMI handler calls this to ack
*/
int smp_handle_nmi_ipi(struct pt_regs *regs)
{
void (*fn)(struct pt_regs *) = NULL;
unsigned long flags;
int me = raw_smp_processor_id();
int ret = 0;
/*
* Unexpected NMIs are possible here because the interrupt may not
* be able to distinguish NMI IPIs from other types of NMIs, or
* because the caller may have timed out.
*/
nmi_ipi_lock_start(&flags);
if (cpumask_test_cpu(me, &nmi_ipi_pending_mask)) {
cpumask_clear_cpu(me, &nmi_ipi_pending_mask);
fn = READ_ONCE(nmi_ipi_function);
WARN_ON_ONCE(!fn);
ret = 1;
}
nmi_ipi_unlock_end(&flags);
if (fn)
fn(regs);
return ret;
}
static void do_smp_send_nmi_ipi(int cpu, bool safe)
{
if (!safe && smp_ops->cause_nmi_ipi && smp_ops->cause_nmi_ipi(cpu))
return;
if (cpu >= 0) {
do_message_pass(cpu, PPC_MSG_NMI_IPI);
} else {
int c;
for_each_online_cpu(c) {
if (c == raw_smp_processor_id())
continue;
do_message_pass(c, PPC_MSG_NMI_IPI);
}
}
}
/*
* - cpu is the target CPU (must not be this CPU), or NMI_IPI_ALL_OTHERS.
* - fn is the target callback function.
* - delay_us > 0 is the delay before giving up waiting for targets to
* begin executing the handler, == 0 specifies indefinite delay.
*/
static int __smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *),
u64 delay_us, bool safe)
{
unsigned long flags;
int me = raw_smp_processor_id();
int ret = 1;
BUG_ON(cpu == me);
BUG_ON(cpu < 0 && cpu != NMI_IPI_ALL_OTHERS);
if (unlikely(!smp_ops))
return 0;
nmi_ipi_lock_start(&flags);
while (nmi_ipi_busy) {
nmi_ipi_unlock_end(&flags);
spin_until_cond(!nmi_ipi_busy);
nmi_ipi_lock_start(&flags);
}
nmi_ipi_busy = true;
nmi_ipi_function = fn;
WARN_ON_ONCE(!cpumask_empty(&nmi_ipi_pending_mask));
if (cpu < 0) {
/* ALL_OTHERS */
cpumask_copy(&nmi_ipi_pending_mask, cpu_online_mask);
cpumask_clear_cpu(me, &nmi_ipi_pending_mask);
} else {
cpumask_set_cpu(cpu, &nmi_ipi_pending_mask);
}
nmi_ipi_unlock();
/* Interrupts remain hard disabled */
do_smp_send_nmi_ipi(cpu, safe);
nmi_ipi_lock();
/* nmi_ipi_busy is set here, so unlock/lock is okay */
while (!cpumask_empty(&nmi_ipi_pending_mask)) {
nmi_ipi_unlock();
udelay(1);
nmi_ipi_lock();
if (delay_us) {
delay_us--;
if (!delay_us)
break;
}
}
if (!cpumask_empty(&nmi_ipi_pending_mask)) {
/* Timeout waiting for CPUs to call smp_handle_nmi_ipi */
ret = 0;
cpumask_clear(&nmi_ipi_pending_mask);
}
nmi_ipi_function = NULL;
nmi_ipi_busy = false;
nmi_ipi_unlock_end(&flags);
return ret;
}
int smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us)
{
return __smp_send_nmi_ipi(cpu, fn, delay_us, false);
}
int smp_send_safe_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us)
{
return __smp_send_nmi_ipi(cpu, fn, delay_us, true);
}
#endif /* CONFIG_NMI_IPI */
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
void tick_broadcast(const struct cpumask *mask)
{
unsigned int cpu;
for_each_cpu(cpu, mask)
do_message_pass(cpu, PPC_MSG_TICK_BROADCAST);
}
#endif
#ifdef CONFIG_DEBUGGER
void debugger_ipi_callback(struct pt_regs *regs)
{
debugger_ipi(regs);
}
void smp_send_debugger_break(void)
{
smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, debugger_ipi_callback, 1000000);
}
#endif
#ifdef CONFIG_KEXEC_CORE
void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
{
int cpu;
smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, crash_ipi_callback, 1000000);
if (kdump_in_progress() && crash_wake_offline) {
for_each_present_cpu(cpu) {
if (cpu_online(cpu))
continue;
/*
* crash_ipi_callback will wait for
* all cpus, including offline CPUs.
* We don't care about nmi_ipi_function.
* Offline cpus will jump straight into
* crash_ipi_callback, we can skip the
* entire NMI dance and waiting for
* cpus to clear pending mask, etc.
*/
do_smp_send_nmi_ipi(cpu, false);
}
}
}
#endif
#ifdef CONFIG_NMI_IPI
static void nmi_stop_this_cpu(struct pt_regs *regs)
{
/*
* IRQs are already hard disabled by the smp_handle_nmi_ipi.
*/
spin_begin();
while (1)
spin_cpu_relax();
}
void smp_send_stop(void)
{
smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, nmi_stop_this_cpu, 1000000);
}
#else /* CONFIG_NMI_IPI */
static void stop_this_cpu(void *dummy)
{
hard_irq_disable();
spin_begin();
while (1)
spin_cpu_relax();
}
void smp_send_stop(void)
{
static bool stopped = false;
/*
* Prevent waiting on csd lock from a previous smp_send_stop.
* This is racy, but in general callers try to do the right
* thing and only fire off one smp_send_stop (e.g., see
* kernel/panic.c)
*/
if (stopped)
return;
stopped = true;
smp_call_function(stop_this_cpu, NULL, 0);
}
#endif /* CONFIG_NMI_IPI */
struct task_struct *current_set[NR_CPUS];
static void smp_store_cpu_info(int id)
{
per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
#ifdef CONFIG_PPC_FSL_BOOK3E
per_cpu(next_tlbcam_idx, id)
= (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
#endif
}
/*
* Relationships between CPUs are maintained in a set of per-cpu cpumasks so
* rather than just passing around the cpumask we pass around a function that
* returns the that cpumask for the given CPU.
*/
static void set_cpus_related(int i, int j, struct cpumask *(*get_cpumask)(int))
{
cpumask_set_cpu(i, get_cpumask(j));
cpumask_set_cpu(j, get_cpumask(i));
}
#ifdef CONFIG_HOTPLUG_CPU
static void set_cpus_unrelated(int i, int j,
struct cpumask *(*get_cpumask)(int))
{
cpumask_clear_cpu(i, get_cpumask(j));
cpumask_clear_cpu(j, get_cpumask(i));
}
#endif
/*
* parse_thread_groups: Parses the "ibm,thread-groups" device tree
* property for the CPU device node @dn and stores
* the parsed output in the thread_groups
* structure @tg if the ibm,thread-groups[0]
* matches @property.
*
* @dn: The device node of the CPU device.
* @tg: Pointer to a thread group structure into which the parsed
* output of "ibm,thread-groups" is stored.
* @property: The property of the thread-group that the caller is
* interested in.
*
* ibm,thread-groups[0..N-1] array defines which group of threads in
* the CPU-device node can be grouped together based on the property.
*
* ibm,thread-groups[0] tells us the property based on which the
* threads are being grouped together. If this value is 1, it implies
* that the threads in the same group share L1, translation cache.
*
* ibm,thread-groups[1] tells us how many such thread groups exist.
*
* ibm,thread-groups[2] tells us the number of threads in each such
* group.
*
* ibm,thread-groups[3..N-1] is the list of threads identified by
* "ibm,ppc-interrupt-server#s" arranged as per their membership in
* the grouping.
*
* Example: If ibm,thread-groups = [1,2,4,5,6,7,8,9,10,11,12] it
* implies that there are 2 groups of 4 threads each, where each group
* of threads share L1, translation cache.
*
* The "ibm,ppc-interrupt-server#s" of the first group is {5,6,7,8}
* and the "ibm,ppc-interrupt-server#s" of the second group is {9, 10,
* 11, 12} structure
*
* Returns 0 on success, -EINVAL if the property does not exist,
* -ENODATA if property does not have a value, and -EOVERFLOW if the
* property data isn't large enough.
*/
static int parse_thread_groups(struct device_node *dn,
struct thread_groups *tg,
unsigned int property)
{
int i;
u32 thread_group_array[3 + MAX_THREAD_LIST_SIZE];
u32 *thread_list;
size_t total_threads;
int ret;
ret = of_property_read_u32_array(dn, "ibm,thread-groups",
thread_group_array, 3);
if (ret)
return ret;
tg->property = thread_group_array[0];
tg->nr_groups = thread_group_array[1];
tg->threads_per_group = thread_group_array[2];
if (tg->property != property ||
tg->nr_groups < 1 ||
tg->threads_per_group < 1)
return -ENODATA;
total_threads = tg->nr_groups * tg->threads_per_group;
ret = of_property_read_u32_array(dn, "ibm,thread-groups",
thread_group_array,
3 + total_threads);
if (ret)
return ret;
thread_list = &thread_group_array[3];
for (i = 0 ; i < total_threads; i++)
tg->thread_list[i] = thread_list[i];
return 0;
}
/*
* get_cpu_thread_group_start : Searches the thread group in tg->thread_list
* that @cpu belongs to.
*
* @cpu : The logical CPU whose thread group is being searched.
* @tg : The thread-group structure of the CPU node which @cpu belongs
* to.
*
* Returns the index to tg->thread_list that points to the the start
* of the thread_group that @cpu belongs to.
*
* Returns -1 if cpu doesn't belong to any of the groups pointed to by
* tg->thread_list.
*/
static int get_cpu_thread_group_start(int cpu, struct thread_groups *tg)
{
int hw_cpu_id = get_hard_smp_processor_id(cpu);
int i, j;
for (i = 0; i < tg->nr_groups; i++) {
int group_start = i * tg->threads_per_group;
for (j = 0; j < tg->threads_per_group; j++) {
int idx = group_start + j;
if (tg->thread_list[idx] == hw_cpu_id)
return group_start;
}
}
return -1;
}
static int init_cpu_l1_cache_map(int cpu)
{
struct device_node *dn = of_get_cpu_node(cpu, NULL);
struct thread_groups tg = {.property = 0,
.nr_groups = 0,
.threads_per_group = 0};
int first_thread = cpu_first_thread_sibling(cpu);
int i, cpu_group_start = -1, err = 0;
if (!dn)
return -ENODATA;
err = parse_thread_groups(dn, &tg, THREAD_GROUP_SHARE_L1);
if (err)
goto out;
zalloc_cpumask_var_node(&per_cpu(cpu_l1_cache_map, cpu),
GFP_KERNEL,
cpu_to_node(cpu));
cpu_group_start = get_cpu_thread_group_start(cpu, &tg);
if (unlikely(cpu_group_start == -1)) {
WARN_ON_ONCE(1);
err = -ENODATA;
goto out;
}
for (i = first_thread; i < first_thread + threads_per_core; i++) {
int i_group_start = get_cpu_thread_group_start(i, &tg);
if (unlikely(i_group_start == -1)) {
WARN_ON_ONCE(1);
err = -ENODATA;
goto out;
}
if (i_group_start == cpu_group_start)
cpumask_set_cpu(i, per_cpu(cpu_l1_cache_map, cpu));
}
out:
of_node_put(dn);
return err;
}
static int init_big_cores(void)
{
int cpu;
for_each_possible_cpu(cpu) {
int err = init_cpu_l1_cache_map(cpu);
if (err)
return err;
zalloc_cpumask_var_node(&per_cpu(cpu_smallcore_map, cpu),
GFP_KERNEL,
cpu_to_node(cpu));
}
has_big_cores = true;
return 0;
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int cpu;
DBG("smp_prepare_cpus\n");
/*
* setup_cpu may need to be called on the boot cpu. We havent
* spun any cpus up but lets be paranoid.
*/
BUG_ON(boot_cpuid != smp_processor_id());
/* Fixup boot cpu */
smp_store_cpu_info(boot_cpuid);
cpu_callin_map[boot_cpuid] = 1;
for_each_possible_cpu(cpu) {
zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
GFP_KERNEL, cpu_to_node(cpu));
zalloc_cpumask_var_node(&per_cpu(cpu_l2_cache_map, cpu),
GFP_KERNEL, cpu_to_node(cpu));
zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
GFP_KERNEL, cpu_to_node(cpu));
/*
* numa_node_id() works after this.
*/
if (cpu_present(cpu)) {
set_cpu_numa_node(cpu, numa_cpu_lookup_table[cpu]);
set_cpu_numa_mem(cpu,
local_memory_node(numa_cpu_lookup_table[cpu]));
}
}
/* Init the cpumasks so the boot CPU is related to itself */
cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
cpumask_set_cpu(boot_cpuid, cpu_l2_cache_mask(boot_cpuid));
cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
init_big_cores();
if (has_big_cores) {
cpumask_set_cpu(boot_cpuid,
cpu_smallcore_mask(boot_cpuid));
}
if (smp_ops && smp_ops->probe)
smp_ops->probe();
}
void smp_prepare_boot_cpu(void)
{
BUG_ON(smp_processor_id() != boot_cpuid);
#ifdef CONFIG_PPC64
paca_ptrs[boot_cpuid]->__current = current;
#endif
set_numa_node(numa_cpu_lookup_table[boot_cpuid]);
current_set[boot_cpuid] = current;
}
#ifdef CONFIG_HOTPLUG_CPU
int generic_cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
if (cpu == boot_cpuid)
return -EBUSY;
set_cpu_online(cpu, false);
#ifdef CONFIG_PPC64
vdso_data->processorCount--;
#endif
/* Update affinity of all IRQs previously aimed at this CPU */
irq_migrate_all_off_this_cpu();
/*
* Depending on the details of the interrupt controller, it's possible
* that one of the interrupts we just migrated away from this CPU is
* actually already pending on this CPU. If we leave it in that state
* the interrupt will never be EOI'ed, and will never fire again. So
* temporarily enable interrupts here, to allow any pending interrupt to
* be received (and EOI'ed), before we take this CPU offline.
*/
local_irq_enable();
mdelay(1);
local_irq_disable();
return 0;
}
void generic_cpu_die(unsigned int cpu)
{
int i;
for (i = 0; i < 100; i++) {
smp_rmb();
if (is_cpu_dead(cpu))
return;
msleep(100);
}
printk(KERN_ERR "CPU%d didn't die...\n", cpu);
}
void generic_set_cpu_dead(unsigned int cpu)
{
per_cpu(cpu_state, cpu) = CPU_DEAD;
}
/*
* The cpu_state should be set to CPU_UP_PREPARE in kick_cpu(), otherwise
* the cpu_state is always CPU_DEAD after calling generic_set_cpu_dead(),
* which makes the delay in generic_cpu_die() not happen.
*/
void generic_set_cpu_up(unsigned int cpu)
{
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
}
int generic_check_cpu_restart(unsigned int cpu)
{
return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
}
int is_cpu_dead(unsigned int cpu)
{
return per_cpu(cpu_state, cpu) == CPU_DEAD;
}
static bool secondaries_inhibited(void)
{
return kvm_hv_mode_active();
}
#else /* HOTPLUG_CPU */
#define secondaries_inhibited() 0
#endif
static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
{
#ifdef CONFIG_PPC64
paca_ptrs[cpu]->__current = idle;
paca_ptrs[cpu]->kstack = (unsigned long)task_stack_page(idle) +
THREAD_SIZE - STACK_FRAME_OVERHEAD;
#endif
idle->cpu = cpu;
secondary_current = current_set[cpu] = idle;
}
int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
int rc, c;
/*
* Don't allow secondary threads to come online if inhibited
*/
if (threads_per_core > 1 && secondaries_inhibited() &&
cpu_thread_in_subcore(cpu))
return -EBUSY;
if (smp_ops == NULL ||
(smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
return -EINVAL;
cpu_idle_thread_init(cpu, tidle);
/*
* The platform might need to allocate resources prior to bringing
* up the CPU
*/
if (smp_ops->prepare_cpu) {
rc = smp_ops->prepare_cpu(cpu);
if (rc)
return rc;
}
/* Make sure callin-map entry is 0 (can be leftover a CPU
* hotplug
*/
cpu_callin_map[cpu] = 0;
/* The information for processor bringup must
* be written out to main store before we release
* the processor.
*/
smp_mb();
/* wake up cpus */
DBG("smp: kicking cpu %d\n", cpu);
rc = smp_ops->kick_cpu(cpu);
if (rc) {
pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
return rc;
}
/*
* wait to see if the cpu made a callin (is actually up).
* use this value that I found through experimentation.
* -- Cort
*/
if (system_state < SYSTEM_RUNNING)
for (c = 50000; c && !cpu_callin_map[cpu]; c--)
udelay(100);
#ifdef CONFIG_HOTPLUG_CPU
else
/*
* CPUs can take much longer to come up in the
* hotplug case. Wait five seconds.
*/
for (c = 5000; c && !cpu_callin_map[cpu]; c--)
msleep(1);
#endif
if (!cpu_callin_map[cpu]) {
printk(KERN_ERR "Processor %u is stuck.\n", cpu);
return -ENOENT;
}
DBG("Processor %u found.\n", cpu);
if (smp_ops->give_timebase)
smp_ops->give_timebase();
/* Wait until cpu puts itself in the online & active maps */
spin_until_cond(cpu_online(cpu));
return 0;
}
/* Return the value of the reg property corresponding to the given
* logical cpu.
*/
int cpu_to_core_id(int cpu)
{
struct device_node *np;
const __be32 *reg;
int id = -1;
np = of_get_cpu_node(cpu, NULL);
if (!np)
goto out;
reg = of_get_property(np, "reg", NULL);
if (!reg)
goto out;
id = be32_to_cpup(reg);
out:
of_node_put(np);
return id;
}
EXPORT_SYMBOL_GPL(cpu_to_core_id);
/* Helper routines for cpu to core mapping */
int cpu_core_index_of_thread(int cpu)
{
return cpu >> threads_shift;
}
EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
int cpu_first_thread_of_core(int core)
{
return core << threads_shift;
}
EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
/* Must be called when no change can occur to cpu_present_mask,
* i.e. during cpu online or offline.
*/
static struct device_node *cpu_to_l2cache(int cpu)
{
struct device_node *np;
struct device_node *cache;
if (!cpu_present(cpu))
return NULL;
np = of_get_cpu_node(cpu, NULL);
if (np == NULL)
return NULL;
cache = of_find_next_cache_node(np);
of_node_put(np);
return cache;
}
static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
{
struct device_node *l2_cache, *np;
int i;
l2_cache = cpu_to_l2cache(cpu);
if (!l2_cache)
return false;
for_each_cpu(i, cpu_online_mask) {
/*
* when updating the marks the current CPU has not been marked
* online, but we need to update the cache masks
*/
np = cpu_to_l2cache(i);
if (!np)
continue;
if (np == l2_cache)
set_cpus_related(cpu, i, mask_fn);
of_node_put(np);
}
of_node_put(l2_cache);
return true;
}
#ifdef CONFIG_HOTPLUG_CPU
static void remove_cpu_from_masks(int cpu)
{
int i;
/* NB: cpu_core_mask is a superset of the others */
for_each_cpu(i, cpu_core_mask(cpu)) {
set_cpus_unrelated(cpu, i, cpu_core_mask);
set_cpus_unrelated(cpu, i, cpu_l2_cache_mask);
set_cpus_unrelated(cpu, i, cpu_sibling_mask);
if (has_big_cores)
set_cpus_unrelated(cpu, i, cpu_smallcore_mask);
}
}
#endif
static inline void add_cpu_to_smallcore_masks(int cpu)
{
struct cpumask *this_l1_cache_map = per_cpu(cpu_l1_cache_map, cpu);
int i, first_thread = cpu_first_thread_sibling(cpu);
if (!has_big_cores)
return;
cpumask_set_cpu(cpu, cpu_smallcore_mask(cpu));
for (i = first_thread; i < first_thread + threads_per_core; i++) {
if (cpu_online(i) && cpumask_test_cpu(i, this_l1_cache_map))
set_cpus_related(i, cpu, cpu_smallcore_mask);
}
}
static void add_cpu_to_masks(int cpu)
{
int first_thread = cpu_first_thread_sibling(cpu);
int chipid = cpu_to_chip_id(cpu);
int i;
/*
* This CPU will not be in the online mask yet so we need to manually
* add it to it's own thread sibling mask.
*/
cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
for (i = first_thread; i < first_thread + threads_per_core; i++)
if (cpu_online(i))
set_cpus_related(i, cpu, cpu_sibling_mask);
add_cpu_to_smallcore_masks(cpu);
/*
* Copy the thread sibling mask into the cache sibling mask
* and mark any CPUs that share an L2 with this CPU.
*/
for_each_cpu(i, cpu_sibling_mask(cpu))
set_cpus_related(cpu, i, cpu_l2_cache_mask);
update_mask_by_l2(cpu, cpu_l2_cache_mask);
/*
* Copy the cache sibling mask into core sibling mask and mark
* any CPUs on the same chip as this CPU.
*/
for_each_cpu(i, cpu_l2_cache_mask(cpu))
set_cpus_related(cpu, i, cpu_core_mask);
if (chipid == -1)
return;
for_each_cpu(i, cpu_online_mask)
if (cpu_to_chip_id(i) == chipid)
set_cpus_related(cpu, i, cpu_core_mask);
}
static bool shared_caches;
/* Activate a secondary processor. */
void start_secondary(void *unused)
{
unsigned int cpu = smp_processor_id();
struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
mmgrab(&init_mm);
current->active_mm = &init_mm;
smp_store_cpu_info(cpu);
set_dec(tb_ticks_per_jiffy);
preempt_disable();
cpu_callin_map[cpu] = 1;
if (smp_ops->setup_cpu)
smp_ops->setup_cpu(cpu);
if (smp_ops->take_timebase)
smp_ops->take_timebase();
secondary_cpu_time_init();
#ifdef CONFIG_PPC64
if (system_state == SYSTEM_RUNNING)
vdso_data->processorCount++;
vdso_getcpu_init();
#endif
/* Update topology CPU masks */
add_cpu_to_masks(cpu);
if (has_big_cores)
sibling_mask = cpu_smallcore_mask;
/*
* Check for any shared caches. Note that this must be done on a
* per-core basis because one core in the pair might be disabled.
*/
if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu)))
shared_caches = true;
set_numa_node(numa_cpu_lookup_table[cpu]);
set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
smp_wmb();
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
boot_init_stack_canary();
local_irq_enable();
/* We can enable ftrace for secondary cpus now */
this_cpu_enable_ftrace();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
BUG();
}
int setup_profiling_timer(unsigned int multiplier)
{
return 0;
}
#ifdef CONFIG_SCHED_SMT
/* cpumask of CPUs with asymetric SMT dependancy */
static int powerpc_smt_flags(void)
{
int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
flags |= SD_ASYM_PACKING;
}
return flags;
}
#endif
static struct sched_domain_topology_level powerpc_topology[] = {
#ifdef CONFIG_SCHED_SMT
{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
#endif
{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
{ NULL, },
};
/*
* P9 has a slightly odd architecture where pairs of cores share an L2 cache.
* This topology makes it *much* cheaper to migrate tasks between adjacent cores
* since the migrated task remains cache hot. We want to take advantage of this
* at the scheduler level so an extra topology level is required.
*/
static int powerpc_shared_cache_flags(void)
{
return SD_SHARE_PKG_RESOURCES;
}
/*
* We can't just pass cpu_l2_cache_mask() directly because
* returns a non-const pointer and the compiler barfs on that.
*/
static const struct cpumask *shared_cache_mask(int cpu)
{
return cpu_l2_cache_mask(cpu);
}
#ifdef CONFIG_SCHED_SMT
static const struct cpumask *smallcore_smt_mask(int cpu)
{
return cpu_smallcore_mask(cpu);
}
#endif
static struct sched_domain_topology_level power9_topology[] = {
#ifdef CONFIG_SCHED_SMT
{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
#endif
{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
{ NULL, },
};
void __init smp_cpus_done(unsigned int max_cpus)
{
/*
* We are running pinned to the boot CPU, see rest_init().
*/
if (smp_ops && smp_ops->setup_cpu)
smp_ops->setup_cpu(boot_cpuid);
if (smp_ops && smp_ops->bringup_done)
smp_ops->bringup_done();
/*
* On a shared LPAR, associativity needs to be requested.
* Hence, get numa topology before dumping cpu topology
*/
shared_proc_topology_init();
dump_numa_cpu_topology();
#ifdef CONFIG_SCHED_SMT
if (has_big_cores) {
pr_info("Using small cores at SMT level\n");
power9_topology[0].mask = smallcore_smt_mask;
powerpc_topology[0].mask = smallcore_smt_mask;
}
#endif
/*
* If any CPU detects that it's sharing a cache with another CPU then
* use the deeper topology that is aware of this sharing.
*/
if (shared_caches) {
pr_info("Using shared cache scheduler topology\n");
set_sched_topology(power9_topology);
} else {
pr_info("Using standard scheduler topology\n");
set_sched_topology(powerpc_topology);
}
}
#ifdef CONFIG_HOTPLUG_CPU
int __cpu_disable(void)
{
int cpu = smp_processor_id();
int err;
if (!smp_ops->cpu_disable)
return -ENOSYS;
this_cpu_disable_ftrace();
err = smp_ops->cpu_disable();
if (err)
return err;
/* Update sibling maps */
remove_cpu_from_masks(cpu);
return 0;
}
void __cpu_die(unsigned int cpu)
{
if (smp_ops->cpu_die)
smp_ops->cpu_die(cpu);
}
void cpu_die(void)
{
/*
* Disable on the down path. This will be re-enabled by
* start_secondary() via start_secondary_resume() below
*/
this_cpu_disable_ftrace();
if (ppc_md.cpu_die)
ppc_md.cpu_die();
/* If we return, we re-enter start_secondary */
start_secondary_resume();
}
#endif
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