/* * 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 * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #undef DEBUG #include <linux/kernel.h> #include <linux/module.h> #include <linux/sched.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/sysdev.h> #include <linux/cpu.h> #include <linux/notifier.h> #include <linux/topology.h> #include <asm/ptrace.h> #include <asm/atomic.h> #include <asm/irq.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/system.h> #include <asm/mpic.h> #include <asm/vdso_datapage.h> #ifdef CONFIG_PPC64 #include <asm/paca.h> #endif #ifdef DEBUG #include <asm/udbg.h> #define DBG(fmt...) udbg_printf(fmt) #else #define DBG(fmt...) #endif /* Store all idle threads, this can be reused instead of creating * a new thread. Also avoids complicated thread destroy functionality * for idle threads. */ #ifdef CONFIG_HOTPLUG_CPU /* * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is * removed after init for !CONFIG_HOTPLUG_CPU. */ static DEFINE_PER_CPU(struct task_struct *, idle_thread_array); #define get_idle_for_cpu(x) (per_cpu(idle_thread_array, x)) #define set_idle_for_cpu(x, p) (per_cpu(idle_thread_array, x) = (p)) #else static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ; #define get_idle_for_cpu(x) (idle_thread_array[(x)]) #define set_idle_for_cpu(x, p) (idle_thread_array[(x)] = (p)) #endif struct thread_info *secondary_ti; DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map); DEFINE_PER_CPU(cpumask_var_t, cpu_core_map); EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); EXPORT_PER_CPU_SYMBOL(cpu_core_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; static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; #ifdef CONFIG_PPC64 int __devinit smp_generic_kick_cpu(int nr) { BUG_ON(nr < 0 || nr >= NR_CPUS); /* * 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 */ paca[nr].cpu_start = 1; smp_mb(); return 0; } #endif void smp_message_recv(int msg) { switch(msg) { case PPC_MSG_CALL_FUNCTION: generic_smp_call_function_interrupt(); break; case PPC_MSG_RESCHEDULE: /* we notice need_resched on exit */ break; case PPC_MSG_CALL_FUNC_SINGLE: generic_smp_call_function_single_interrupt(); break; case PPC_MSG_DEBUGGER_BREAK: if (crash_ipi_function_ptr) { crash_ipi_function_ptr(get_irq_regs()); break; } #ifdef CONFIG_DEBUGGER debugger_ipi(get_irq_regs()); break; #endif /* CONFIG_DEBUGGER */ /* FALLTHROUGH */ default: printk("SMP %d: smp_message_recv(): unknown msg %d\n", smp_processor_id(), msg); break; } } 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) { /* we just need the return path side effect of checking need_resched */ return IRQ_HANDLED; } static irqreturn_t call_function_single_action(int irq, void *data) { generic_smp_call_function_single_interrupt(); return IRQ_HANDLED; } static irqreturn_t debug_ipi_action(int irq, void *data) { smp_message_recv(PPC_MSG_DEBUGGER_BREAK); return IRQ_HANDLED; } static irq_handler_t smp_ipi_action[] = { [PPC_MSG_CALL_FUNCTION] = call_function_action, [PPC_MSG_RESCHEDULE] = reschedule_action, [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action, [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action, }; const char *smp_ipi_name[] = { [PPC_MSG_CALL_FUNCTION] = "ipi call function", [PPC_MSG_RESCHEDULE] = "ipi reschedule", [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single", [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger", }; /* 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_DEBUGGER_BREAK) { return -EINVAL; } #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC) if (msg == PPC_MSG_DEBUGGER_BREAK) { return 1; } #endif err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU, smp_ipi_name[msg], 0); WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n", virq, smp_ipi_name[msg], err); return err; } void smp_send_reschedule(int cpu) { if (likely(smp_ops)) smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); } void arch_send_call_function_single_ipi(int cpu) { smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); } void arch_send_call_function_ipi_mask(const struct cpumask *mask) { unsigned int cpu; for_each_cpu(cpu, mask) smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION); } #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC) void smp_send_debugger_break(void) { int cpu; int me = raw_smp_processor_id(); if (unlikely(!smp_ops)) return; for_each_online_cpu(cpu) if (cpu != me) smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); } #endif #ifdef CONFIG_KEXEC void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) { crash_ipi_function_ptr = crash_ipi_callback; if (crash_ipi_callback) { mb(); smp_send_debugger_break(); } } #endif static void stop_this_cpu(void *dummy) { /* Remove this CPU */ set_cpu_online(smp_processor_id(), false); local_irq_disable(); while (1) ; } void smp_send_stop(void) { smp_call_function(stop_this_cpu, NULL, 0); } struct thread_info *current_set[NR_CPUS]; static void __devinit smp_store_cpu_info(int id) { per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR); } 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_core_map, cpu), GFP_KERNEL, cpu_to_node(cpu)); } cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid)); cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid)); if (smp_ops) if (smp_ops->probe) max_cpus = smp_ops->probe(); else max_cpus = NR_CPUS; else max_cpus = 1; } void __devinit smp_prepare_boot_cpu(void) { BUG_ON(smp_processor_id() != boot_cpuid); #ifdef CONFIG_PPC64 paca[boot_cpuid].__current = current; #endif current_set[boot_cpuid] = task_thread_info(current); } #ifdef CONFIG_HOTPLUG_CPU /* State of each CPU during hotplug phases */ static DEFINE_PER_CPU(int, cpu_state) = { 0 }; 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 migrate_irqs(); return 0; } void generic_cpu_die(unsigned int cpu) { int i; for (i = 0; i < 100; i++) { smp_rmb(); if (per_cpu(cpu_state, cpu) == CPU_DEAD) return; msleep(100); } printk(KERN_ERR "CPU%d didn't die...\n", cpu); } void generic_mach_cpu_die(void) { unsigned int cpu; local_irq_disable(); idle_task_exit(); cpu = smp_processor_id(); printk(KERN_DEBUG "CPU%d offline\n", cpu); __get_cpu_var(cpu_state) = CPU_DEAD; smp_wmb(); while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) cpu_relax(); } void generic_set_cpu_dead(unsigned int cpu) { per_cpu(cpu_state, cpu) = CPU_DEAD; } #endif struct create_idle { struct work_struct work; struct task_struct *idle; struct completion done; int cpu; }; static void __cpuinit do_fork_idle(struct work_struct *work) { struct create_idle *c_idle = container_of(work, struct create_idle, work); c_idle->idle = fork_idle(c_idle->cpu); complete(&c_idle->done); } static int __cpuinit create_idle(unsigned int cpu) { struct thread_info *ti; struct create_idle c_idle = { .cpu = cpu, .done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done), }; INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle); c_idle.idle = get_idle_for_cpu(cpu); /* We can't use kernel_thread since we must avoid to * reschedule the child. We use a workqueue because * we want to fork from a kernel thread, not whatever * userspace process happens to be trying to online us. */ if (!c_idle.idle) { schedule_work(&c_idle.work); wait_for_completion(&c_idle.done); } else init_idle(c_idle.idle, cpu); if (IS_ERR(c_idle.idle)) { pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle)); return PTR_ERR(c_idle.idle); } ti = task_thread_info(c_idle.idle); #ifdef CONFIG_PPC64 paca[cpu].__current = c_idle.idle; paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD; #endif ti->cpu = cpu; current_set[cpu] = ti; return 0; } int __cpuinit __cpu_up(unsigned int cpu) { int rc, c; secondary_ti = current_set[cpu]; if (smp_ops == NULL || (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))) return -EINVAL; /* Make sure we have an idle thread */ rc = create_idle(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 map */ while (!cpu_online(cpu)) cpu_relax(); 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 int *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 = *reg; out: of_node_put(np); return 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; } /* Activate a secondary processor. */ void __devinit start_secondary(void *unused) { unsigned int cpu = smp_processor_id(); struct device_node *l2_cache; int i, base; atomic_inc(&init_mm.mm_count); 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++; #endif ipi_call_lock(); notify_cpu_starting(cpu); set_cpu_online(cpu, true); /* Update sibling maps */ base = cpu_first_thread_sibling(cpu); for (i = 0; i < threads_per_core; i++) { if (cpu_is_offline(base + i)) continue; cpumask_set_cpu(cpu, cpu_sibling_mask(base + i)); cpumask_set_cpu(base + i, cpu_sibling_mask(cpu)); /* cpu_core_map should be a superset of * cpu_sibling_map even if we don't have cache * information, so update the former here, too. */ cpumask_set_cpu(cpu, cpu_core_mask(base + i)); cpumask_set_cpu(base + i, cpu_core_mask(cpu)); } l2_cache = cpu_to_l2cache(cpu); for_each_online_cpu(i) { struct device_node *np = cpu_to_l2cache(i); if (!np) continue; if (np == l2_cache) { cpumask_set_cpu(cpu, cpu_core_mask(i)); cpumask_set_cpu(i, cpu_core_mask(cpu)); } of_node_put(np); } of_node_put(l2_cache); ipi_call_unlock(); local_irq_enable(); cpu_idle(); BUG(); } int setup_profiling_timer(unsigned int multiplier) { return 0; } void __init smp_cpus_done(unsigned int max_cpus) { cpumask_var_t old_mask; /* We want the setup_cpu() here to be called from CPU 0, but our * init thread may have been "borrowed" by another CPU in the meantime * se we pin us down to CPU 0 for a short while */ alloc_cpumask_var(&old_mask, GFP_NOWAIT); cpumask_copy(old_mask, tsk_cpus_allowed(current)); set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid)); if (smp_ops && smp_ops->setup_cpu) smp_ops->setup_cpu(boot_cpuid); set_cpus_allowed_ptr(current, old_mask); free_cpumask_var(old_mask); if (smp_ops && smp_ops->bringup_done) smp_ops->bringup_done(); dump_numa_cpu_topology(); } int arch_sd_sibling_asym_packing(void) { if (cpu_has_feature(CPU_FTR_ASYM_SMT)) { printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n"); return SD_ASYM_PACKING; } return 0; } #ifdef CONFIG_HOTPLUG_CPU int __cpu_disable(void) { struct device_node *l2_cache; int cpu = smp_processor_id(); int base, i; int err; if (!smp_ops->cpu_disable) return -ENOSYS; err = smp_ops->cpu_disable(); if (err) return err; /* Update sibling maps */ base = cpu_first_thread_sibling(cpu); for (i = 0; i < threads_per_core; i++) { cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i)); cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu)); cpumask_clear_cpu(cpu, cpu_core_mask(base + i)); cpumask_clear_cpu(base + i, cpu_core_mask(cpu)); } l2_cache = cpu_to_l2cache(cpu); for_each_present_cpu(i) { struct device_node *np = cpu_to_l2cache(i); if (!np) continue; if (np == l2_cache) { cpumask_clear_cpu(cpu, cpu_core_mask(i)); cpumask_clear_cpu(i, cpu_core_mask(cpu)); } of_node_put(np); } of_node_put(l2_cache); return 0; } void __cpu_die(unsigned int cpu) { if (smp_ops->cpu_die) smp_ops->cpu_die(cpu); } static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex); void cpu_hotplug_driver_lock() { mutex_lock(&powerpc_cpu_hotplug_driver_mutex); } void cpu_hotplug_driver_unlock() { mutex_unlock(&powerpc_cpu_hotplug_driver_mutex); } void cpu_die(void) { if (ppc_md.cpu_die) ppc_md.cpu_die(); /* If we return, we re-enter start_secondary */ start_secondary_resume(); } #endif