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Diffstat (limited to 'arch/powerpc/kernel/smp.c')
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 1636 |
1 files changed, 1636 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c new file mode 100644 index 000000000..cf99f57ae --- /dev/null +++ b/arch/powerpc/kernel/smp.c @@ -0,0 +1,1636 @@ +// 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 <linux/pgtable.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/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> +#include <asm/kup.h> +#include <asm/fadump.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; +bool coregroup_enabled; + +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); +DEFINE_PER_CPU(cpumask_var_t, cpu_coregroup_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); + +enum { +#ifdef CONFIG_SCHED_SMT + smt_idx, +#endif + cache_idx, + mc_idx, + die_idx, +}; + +#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 crash_stop_this_cpu(struct pt_regs *regs) +#else +static void crash_stop_this_cpu(void *dummy) +#endif +{ + /* + * Just busy wait here and avoid marking CPU as offline to ensure + * register data is captured appropriately. + */ + while (1) + cpu_relax(); +} + +void crash_smp_send_stop(void) +{ + static bool stopped = false; + + /* + * In case of fadump, register data for all CPUs is captured by f/w + * on ibm,os-term rtas call. Skip IPI callbacks to other CPUs before + * this rtas call to avoid tricky post processing of those CPUs' + * backtraces. + */ + if (should_fadump_crash()) + return; + + if (stopped) + return; + + stopped = true; + +#ifdef CONFIG_NMI_IPI + smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, crash_stop_this_cpu, 1000000); +#else + smp_call_function(crash_stop_this_cpu, NULL, 0); +#endif /* CONFIG_NMI_IPI */ +} + +#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. + */ + set_cpu_online(smp_processor_id(), false); + + 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(); + + /* + * Offlining CPUs in stop_this_cpu can result in scheduler warnings, + * (see commit de6e5d38417e), but printk_safe_flush_on_panic() wants + * to know other CPUs are offline before it breaks locks to flush + * printk buffers, in case we panic()ed while holding the lock. + */ + set_cpu_online(smp_processor_id(), false); + + 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 + +/* + * Extends set_cpus_related. Instead of setting one CPU at a time in + * dstmask, set srcmask at oneshot. dstmask should be super set of srcmask. + */ +static void or_cpumasks_related(int i, int j, struct cpumask *(*srcmask)(int), + struct cpumask *(*dstmask)(int)) +{ + struct cpumask *mask; + int k; + + mask = srcmask(j); + for_each_cpu(k, srcmask(i)) + cpumask_or(dstmask(k), dstmask(k), mask); + + if (i == j) + return; + + mask = srcmask(i); + for_each_cpu(k, srcmask(j)) + cpumask_or(dstmask(k), dstmask(k), mask); +} + +/* + * 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; + + cpu_group_start = get_cpu_thread_group_start(cpu, &tg); + + if (unlikely(cpu_group_start == -1)) { + WARN_ON_ONCE(1); + err = -ENODATA; + goto out; + } + + zalloc_cpumask_var_node(&per_cpu(cpu_l1_cache_map, cpu), + GFP_KERNEL, cpu_to_node(cpu)); + + 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 bool shared_caches; + +#ifdef CONFIG_SCHED_SMT +/* cpumask of CPUs with asymmetric SMT dependency */ +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 + +/* + * 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 per_cpu(cpu_l2_cache_map, cpu); +} + +#ifdef CONFIG_SCHED_SMT +static const struct cpumask *smallcore_smt_mask(int cpu) +{ + return cpu_smallcore_mask(cpu); +} +#endif + +static struct cpumask *cpu_coregroup_mask(int cpu) +{ + return per_cpu(cpu_coregroup_map, cpu); +} + +static bool has_coregroup_support(void) +{ + return coregroup_enabled; +} + +static const struct cpumask *cpu_mc_mask(int cpu) +{ + return cpu_coregroup_mask(cpu); +} + +static struct sched_domain_topology_level powerpc_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_mc_mask, SD_INIT_NAME(MC) }, + { cpu_cpu_mask, SD_INIT_NAME(DIE) }, + { NULL, }, +}; + +static int __init 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)); + if (has_coregroup_support()) + zalloc_cpumask_var_node(&per_cpu(cpu_coregroup_map, cpu), + GFP_KERNEL, cpu_to_node(cpu)); + +#ifdef CONFIG_NEED_MULTIPLE_NODES + /* + * 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])); + } +#endif + } + + /* 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)); + + if (has_coregroup_support()) + cpumask_set_cpu(boot_cpuid, cpu_coregroup_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, cpumask_var_t *mask) +{ + struct cpumask *(*submask_fn)(int) = cpu_sibling_mask; + struct device_node *l2_cache, *np; + int i; + + if (has_big_cores) + submask_fn = cpu_smallcore_mask; + + l2_cache = cpu_to_l2cache(cpu); + if (!l2_cache || !*mask) { + /* Assume only core siblings share cache with this CPU */ + for_each_cpu(i, submask_fn(cpu)) + set_cpus_related(cpu, i, cpu_l2_cache_mask); + + return false; + } + + cpumask_and(*mask, cpu_online_mask, cpu_cpu_mask(cpu)); + + /* Update l2-cache mask with all the CPUs that are part of submask */ + or_cpumasks_related(cpu, cpu, submask_fn, cpu_l2_cache_mask); + + /* Skip all CPUs already part of current CPU l2-cache mask */ + cpumask_andnot(*mask, *mask, cpu_l2_cache_mask(cpu)); + + for_each_cpu(i, *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); + + /* Skip all CPUs already part of current CPU l2-cache */ + if (np == l2_cache) { + or_cpumasks_related(cpu, i, submask_fn, cpu_l2_cache_mask); + cpumask_andnot(*mask, *mask, submask_fn(i)); + } else { + cpumask_andnot(*mask, *mask, cpu_l2_cache_mask(i)); + } + + of_node_put(np); + } + of_node_put(l2_cache); + + return true; +} + +#ifdef CONFIG_HOTPLUG_CPU +static void remove_cpu_from_masks(int cpu) +{ + struct cpumask *(*mask_fn)(int) = cpu_sibling_mask; + int i; + + if (shared_caches) + mask_fn = cpu_l2_cache_mask; + + for_each_cpu(i, mask_fn(cpu)) { + 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); + } + + for_each_cpu(i, cpu_core_mask(cpu)) + set_cpus_unrelated(cpu, i, cpu_core_mask); + + if (has_coregroup_support()) { + for_each_cpu(i, cpu_coregroup_mask(cpu)) + set_cpus_unrelated(cpu, i, cpu_coregroup_mask); + } +} +#endif + +static inline void add_cpu_to_smallcore_masks(int cpu) +{ + int i; + + if (!has_big_cores) + return; + + cpumask_set_cpu(cpu, cpu_smallcore_mask(cpu)); + + for_each_cpu(i, per_cpu(cpu_l1_cache_map, cpu)) { + if (cpu_online(i)) + set_cpus_related(i, cpu, cpu_smallcore_mask); + } +} + +static void update_coregroup_mask(int cpu, cpumask_var_t *mask) +{ + struct cpumask *(*submask_fn)(int) = cpu_sibling_mask; + int coregroup_id = cpu_to_coregroup_id(cpu); + int i; + + if (shared_caches) + submask_fn = cpu_l2_cache_mask; + + if (!*mask) { + /* Assume only siblings are part of this CPU's coregroup */ + for_each_cpu(i, submask_fn(cpu)) + set_cpus_related(cpu, i, cpu_coregroup_mask); + + return; + } + + cpumask_and(*mask, cpu_online_mask, cpu_cpu_mask(cpu)); + + /* Update coregroup mask with all the CPUs that are part of submask */ + or_cpumasks_related(cpu, cpu, submask_fn, cpu_coregroup_mask); + + /* Skip all CPUs already part of coregroup mask */ + cpumask_andnot(*mask, *mask, cpu_coregroup_mask(cpu)); + + for_each_cpu(i, *mask) { + /* Skip all CPUs not part of this coregroup */ + if (coregroup_id == cpu_to_coregroup_id(i)) { + or_cpumasks_related(cpu, i, submask_fn, cpu_coregroup_mask); + cpumask_andnot(*mask, *mask, submask_fn(i)); + } else { + cpumask_andnot(*mask, *mask, cpu_coregroup_mask(i)); + } + } +} + +static void add_cpu_to_masks(int cpu) +{ + struct cpumask *(*submask_fn)(int) = cpu_sibling_mask; + int first_thread = cpu_first_thread_sibling(cpu); + int chip_id = cpu_to_chip_id(cpu); + cpumask_var_t mask; + bool ret; + 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)); + cpumask_set_cpu(cpu, cpu_core_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); + + /* In CPU-hotplug path, hence use GFP_ATOMIC */ + ret = alloc_cpumask_var_node(&mask, GFP_ATOMIC, cpu_to_node(cpu)); + update_mask_by_l2(cpu, &mask); + + if (has_coregroup_support()) + update_coregroup_mask(cpu, &mask); + + if (shared_caches) + submask_fn = cpu_l2_cache_mask; + + /* Update core_mask with all the CPUs that are part of submask */ + or_cpumasks_related(cpu, cpu, submask_fn, cpu_core_mask); + + /* Skip all CPUs already part of current CPU core mask */ + cpumask_andnot(mask, cpu_online_mask, cpu_core_mask(cpu)); + + /* If chip_id is -1; limit the cpu_core_mask to within DIE*/ + if (chip_id == -1) + cpumask_and(mask, mask, cpu_cpu_mask(cpu)); + + for_each_cpu(i, mask) { + if (chip_id == cpu_to_chip_id(i)) { + or_cpumasks_related(cpu, i, submask_fn, cpu_core_mask); + cpumask_andnot(mask, mask, submask_fn(i)); + } else { + cpumask_andnot(mask, mask, cpu_core_mask(i)); + } + } + + free_cpumask_var(mask); +} + +/* Activate a secondary processor. */ +void start_secondary(void *unused) +{ + unsigned int cpu = raw_smp_processor_id(); + + mmgrab(&init_mm); + current->active_mm = &init_mm; + + smp_store_cpu_info(cpu); + set_dec(tb_ticks_per_jiffy); + rcu_cpu_starting(cpu); + 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 + set_numa_node(numa_cpu_lookup_table[cpu]); + set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu])); + + /* Update topology CPU masks */ + add_cpu_to_masks(cpu); + + /* + * 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 (!shared_caches) { + struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; + struct cpumask *mask = cpu_l2_cache_mask(cpu); + + if (has_big_cores) + sibling_mask = cpu_smallcore_mask; + + if (cpumask_weight(mask) > cpumask_weight(sibling_mask(cpu))) + shared_caches = true; + } + + 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(); +} + +#ifdef CONFIG_PROFILING +int setup_profiling_timer(unsigned int multiplier) +{ + return 0; +} +#endif + +static void fixup_topology(void) +{ + int i; + +#ifdef CONFIG_SCHED_SMT + if (has_big_cores) { + pr_info("Big cores detected but using small core scheduling\n"); + powerpc_topology[smt_idx].mask = smallcore_smt_mask; + } +#endif + + if (!has_coregroup_support()) + powerpc_topology[mc_idx].mask = powerpc_topology[cache_idx].mask; + + /* + * Try to consolidate topology levels here instead of + * allowing scheduler to degenerate. + * - Dont consolidate if masks are different. + * - Dont consolidate if sd_flags exists and are different. + */ + for (i = 1; i <= die_idx; i++) { + if (powerpc_topology[i].mask != powerpc_topology[i - 1].mask) + continue; + + if (powerpc_topology[i].sd_flags && powerpc_topology[i - 1].sd_flags && + powerpc_topology[i].sd_flags != powerpc_topology[i - 1].sd_flags) + continue; + + if (!powerpc_topology[i - 1].sd_flags) + powerpc_topology[i - 1].sd_flags = powerpc_topology[i].sd_flags; + + powerpc_topology[i].mask = powerpc_topology[i + 1].mask; + powerpc_topology[i].sd_flags = powerpc_topology[i + 1].sd_flags; +#ifdef CONFIG_SCHED_DEBUG + powerpc_topology[i].name = powerpc_topology[i + 1].name; +#endif + } +} + +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(); + + dump_numa_cpu_topology(); + + fixup_topology(); + 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 arch_cpu_idle_dead(void) +{ + /* + * Disable on the down path. This will be re-enabled by + * start_secondary() via start_secondary_resume() below + */ + this_cpu_disable_ftrace(); + + if (smp_ops->cpu_offline_self) + smp_ops->cpu_offline_self(); + + /* If we return, we re-enter start_secondary */ + start_secondary_resume(); +} + +#endif |