/* * linux/arch/arm/kernel/smp.c * * Copyright (C) 2002 ARM Limited, All Rights Reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * as from 2.5, kernels no longer have an init_tasks structure * so we need some other way of telling a new secondary core * where to place its SVC stack */ struct secondary_data secondary_data; /* * control for which core is the next to come out of the secondary * boot "holding pen" */ volatile int __cpuinitdata pen_release = -1; enum ipi_msg_type { IPI_WAKEUP, IPI_TIMER, IPI_RESCHEDULE, IPI_CALL_FUNC, IPI_CALL_FUNC_SINGLE, IPI_CPU_STOP, }; static DECLARE_COMPLETION(cpu_running); static struct smp_operations smp_ops; void __init smp_set_ops(struct smp_operations *ops) { if (ops) smp_ops = *ops; }; int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle) { int ret; /* * We need to tell the secondary core where to find * its stack and the page tables. */ secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; secondary_data.pgdir = virt_to_phys(idmap_pgd); secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir); __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data)); outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1)); /* * Now bring the CPU into our world. */ ret = boot_secondary(cpu, idle); if (ret == 0) { /* * CPU was successfully started, wait for it * to come online or time out. */ wait_for_completion_timeout(&cpu_running, msecs_to_jiffies(1000)); if (!cpu_online(cpu)) { pr_crit("CPU%u: failed to come online\n", cpu); ret = -EIO; } } else { pr_err("CPU%u: failed to boot: %d\n", cpu, ret); } secondary_data.stack = NULL; secondary_data.pgdir = 0; return ret; } /* platform specific SMP operations */ void __init smp_init_cpus(void) { if (smp_ops.smp_init_cpus) smp_ops.smp_init_cpus(); } int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) { if (smp_ops.smp_boot_secondary) return smp_ops.smp_boot_secondary(cpu, idle); return -ENOSYS; } #ifdef CONFIG_HOTPLUG_CPU static void percpu_timer_stop(void); static int platform_cpu_kill(unsigned int cpu) { if (smp_ops.cpu_kill) return smp_ops.cpu_kill(cpu); return 1; } static int platform_cpu_disable(unsigned int cpu) { if (smp_ops.cpu_disable) return smp_ops.cpu_disable(cpu); /* * By default, allow disabling all CPUs except the first one, * since this is special on a lot of platforms, e.g. because * of clock tick interrupts. */ return cpu == 0 ? -EPERM : 0; } /* * __cpu_disable runs on the processor to be shutdown. */ int __cpuinit __cpu_disable(void) { unsigned int cpu = smp_processor_id(); int ret; ret = platform_cpu_disable(cpu); if (ret) return ret; /* * Take this CPU offline. Once we clear this, we can't return, * and we must not schedule until we're ready to give up the cpu. */ set_cpu_online(cpu, false); /* * OK - migrate IRQs away from this CPU */ migrate_irqs(); /* * Stop the local timer for this CPU. */ percpu_timer_stop(); /* * Flush user cache and TLB mappings, and then remove this CPU * from the vm mask set of all processes. * * Caches are flushed to the Level of Unification Inner Shareable * to write-back dirty lines to unified caches shared by all CPUs. */ flush_cache_louis(); local_flush_tlb_all(); clear_tasks_mm_cpumask(cpu); return 0; } static DECLARE_COMPLETION(cpu_died); /* * called on the thread which is asking for a CPU to be shutdown - * waits until shutdown has completed, or it is timed out. */ void __cpuinit __cpu_die(unsigned int cpu) { if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) { pr_err("CPU%u: cpu didn't die\n", cpu); return; } printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); /* * platform_cpu_kill() is generally expected to do the powering off * and/or cutting of clocks to the dying CPU. Optionally, this may * be done by the CPU which is dying in preference to supporting * this call, but that means there is _no_ synchronisation between * the requesting CPU and the dying CPU actually losing power. */ if (!platform_cpu_kill(cpu)) printk("CPU%u: unable to kill\n", cpu); } /* * Called from the idle thread for the CPU which has been shutdown. * * Note that we disable IRQs here, but do not re-enable them * before returning to the caller. This is also the behaviour * of the other hotplug-cpu capable cores, so presumably coming * out of idle fixes this. */ void __ref cpu_die(void) { unsigned int cpu = smp_processor_id(); idle_task_exit(); local_irq_disable(); /* * Flush the data out of the L1 cache for this CPU. This must be * before the completion to ensure that data is safely written out * before platform_cpu_kill() gets called - which may disable * *this* CPU and power down its cache. */ flush_cache_louis(); /* * Tell __cpu_die() that this CPU is now safe to dispose of. Once * this returns, power and/or clocks can be removed at any point * from this CPU and its cache by platform_cpu_kill(). */ complete(&cpu_died); /* * Ensure that the cache lines associated with that completion are * written out. This covers the case where _this_ CPU is doing the * powering down, to ensure that the completion is visible to the * CPU waiting for this one. */ flush_cache_louis(); /* * The actual CPU shutdown procedure is at least platform (if not * CPU) specific. This may remove power, or it may simply spin. * * Platforms are generally expected *NOT* to return from this call, * although there are some which do because they have no way to * power down the CPU. These platforms are the _only_ reason we * have a return path which uses the fragment of assembly below. * * The return path should not be used for platforms which can * power off the CPU. */ if (smp_ops.cpu_die) smp_ops.cpu_die(cpu); /* * Do not return to the idle loop - jump back to the secondary * cpu initialisation. There's some initialisation which needs * to be repeated to undo the effects of taking the CPU offline. */ __asm__("mov sp, %0\n" " mov fp, #0\n" " b secondary_start_kernel" : : "r" (task_stack_page(current) + THREAD_SIZE - 8)); } #endif /* CONFIG_HOTPLUG_CPU */ /* * Called by both boot and secondaries to move global data into * per-processor storage. */ static void __cpuinit smp_store_cpu_info(unsigned int cpuid) { struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); cpu_info->loops_per_jiffy = loops_per_jiffy; cpu_info->cpuid = read_cpuid_id(); store_cpu_topology(cpuid); } static void percpu_timer_setup(void); /* * This is the secondary CPU boot entry. We're using this CPUs * idle thread stack, but a set of temporary page tables. */ asmlinkage void __cpuinit secondary_start_kernel(void) { struct mm_struct *mm = &init_mm; unsigned int cpu; /* * The identity mapping is uncached (strongly ordered), so * switch away from it before attempting any exclusive accesses. */ cpu_switch_mm(mm->pgd, mm); local_flush_bp_all(); enter_lazy_tlb(mm, current); local_flush_tlb_all(); /* * All kernel threads share the same mm context; grab a * reference and switch to it. */ cpu = smp_processor_id(); atomic_inc(&mm->mm_count); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); cpu_init(); printk("CPU%u: Booted secondary processor\n", cpu); preempt_disable(); trace_hardirqs_off(); /* * Give the platform a chance to do its own initialisation. */ if (smp_ops.smp_secondary_init) smp_ops.smp_secondary_init(cpu); notify_cpu_starting(cpu); calibrate_delay(); smp_store_cpu_info(cpu); /* * OK, now it's safe to let the boot CPU continue. Wait for * the CPU migration code to notice that the CPU is online * before we continue - which happens after __cpu_up returns. */ set_cpu_online(cpu, true); complete(&cpu_running); /* * Setup the percpu timer for this CPU. */ percpu_timer_setup(); local_irq_enable(); local_fiq_enable(); /* * OK, it's off to the idle thread for us */ cpu_startup_entry(CPUHP_ONLINE); } void __init smp_cpus_done(unsigned int max_cpus) { int cpu; unsigned long bogosum = 0; for_each_online_cpu(cpu) bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy; printk(KERN_INFO "SMP: Total of %d processors activated " "(%lu.%02lu BogoMIPS).\n", num_online_cpus(), bogosum / (500000/HZ), (bogosum / (5000/HZ)) % 100); hyp_mode_check(); } void __init smp_prepare_boot_cpu(void) { set_my_cpu_offset(per_cpu_offset(smp_processor_id())); } void __init smp_prepare_cpus(unsigned int max_cpus) { unsigned int ncores = num_possible_cpus(); init_cpu_topology(); smp_store_cpu_info(smp_processor_id()); /* * are we trying to boot more cores than exist? */ if (max_cpus > ncores) max_cpus = ncores; if (ncores > 1 && max_cpus) { /* * Enable the local timer or broadcast device for the * boot CPU, but only if we have more than one CPU. */ percpu_timer_setup(); /* * Initialise the present map, which describes the set of CPUs * actually populated at the present time. A platform should * re-initialize the map in the platforms smp_prepare_cpus() * if present != possible (e.g. physical hotplug). */ init_cpu_present(cpu_possible_mask); /* * Initialise the SCU if there are more than one CPU * and let them know where to start. */ if (smp_ops.smp_prepare_cpus) smp_ops.smp_prepare_cpus(max_cpus); } } static void (*smp_cross_call)(const struct cpumask *, unsigned int); void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int)) { if (!smp_cross_call) smp_cross_call = fn; } void arch_send_call_function_ipi_mask(const struct cpumask *mask) { smp_cross_call(mask, IPI_CALL_FUNC); } void arch_send_wakeup_ipi_mask(const struct cpumask *mask) { smp_cross_call(mask, IPI_WAKEUP); } void arch_send_call_function_single_ipi(int cpu) { smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE); } static const char *ipi_types[NR_IPI] = { #define S(x,s) [x] = s S(IPI_WAKEUP, "CPU wakeup interrupts"), S(IPI_TIMER, "Timer broadcast interrupts"), S(IPI_RESCHEDULE, "Rescheduling interrupts"), S(IPI_CALL_FUNC, "Function call interrupts"), S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"), S(IPI_CPU_STOP, "CPU stop interrupts"), }; void show_ipi_list(struct seq_file *p, int prec) { unsigned int cpu, i; for (i = 0; i < NR_IPI; i++) { seq_printf(p, "%*s%u: ", prec - 1, "IPI", i); for_each_online_cpu(cpu) seq_printf(p, "%10u ", __get_irq_stat(cpu, ipi_irqs[i])); seq_printf(p, " %s\n", ipi_types[i]); } } u64 smp_irq_stat_cpu(unsigned int cpu) { u64 sum = 0; int i; for (i = 0; i < NR_IPI; i++) sum += __get_irq_stat(cpu, ipi_irqs[i]); return sum; } /* * Timer (local or broadcast) support */ static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent); #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST void tick_broadcast(const struct cpumask *mask) { smp_cross_call(mask, IPI_TIMER); } #endif static void broadcast_timer_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) { } static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt) { evt->name = "dummy_timer"; evt->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_DUMMY; evt->rating = 100; evt->mult = 1; evt->set_mode = broadcast_timer_set_mode; clockevents_register_device(evt); } static struct local_timer_ops *lt_ops; #ifdef CONFIG_LOCAL_TIMERS int local_timer_register(struct local_timer_ops *ops) { if (!is_smp() || !setup_max_cpus) return -ENXIO; if (lt_ops) return -EBUSY; lt_ops = ops; return 0; } #endif static void __cpuinit percpu_timer_setup(void) { unsigned int cpu = smp_processor_id(); struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu); evt->cpumask = cpumask_of(cpu); if (!lt_ops || lt_ops->setup(evt)) broadcast_timer_setup(evt); } #ifdef CONFIG_HOTPLUG_CPU /* * The generic clock events code purposely does not stop the local timer * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it * manually here. */ static void percpu_timer_stop(void) { unsigned int cpu = smp_processor_id(); struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu); if (lt_ops) lt_ops->stop(evt); } #endif static DEFINE_RAW_SPINLOCK(stop_lock); /* * ipi_cpu_stop - handle IPI from smp_send_stop() */ static void ipi_cpu_stop(unsigned int cpu) { if (system_state == SYSTEM_BOOTING || system_state == SYSTEM_RUNNING) { raw_spin_lock(&stop_lock); printk(KERN_CRIT "CPU%u: stopping\n", cpu); dump_stack(); raw_spin_unlock(&stop_lock); } set_cpu_online(cpu, false); local_fiq_disable(); local_irq_disable(); while (1) cpu_relax(); } /* * Main handler for inter-processor interrupts */ asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs) { handle_IPI(ipinr, regs); } void handle_IPI(int ipinr, struct pt_regs *regs) { unsigned int cpu = smp_processor_id(); struct pt_regs *old_regs = set_irq_regs(regs); if (ipinr < NR_IPI) __inc_irq_stat(cpu, ipi_irqs[ipinr]); switch (ipinr) { case IPI_WAKEUP: break; #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST case IPI_TIMER: irq_enter(); tick_receive_broadcast(); irq_exit(); break; #endif case IPI_RESCHEDULE: scheduler_ipi(); break; case IPI_CALL_FUNC: irq_enter(); generic_smp_call_function_interrupt(); irq_exit(); break; case IPI_CALL_FUNC_SINGLE: irq_enter(); generic_smp_call_function_single_interrupt(); irq_exit(); break; case IPI_CPU_STOP: irq_enter(); ipi_cpu_stop(cpu); irq_exit(); break; default: printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr); break; } set_irq_regs(old_regs); } void smp_send_reschedule(int cpu) { smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); } void smp_send_stop(void) { unsigned long timeout; struct cpumask mask; cpumask_copy(&mask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &mask); if (!cpumask_empty(&mask)) smp_cross_call(&mask, IPI_CPU_STOP); /* Wait up to one second for other CPUs to stop */ timeout = USEC_PER_SEC; while (num_online_cpus() > 1 && timeout--) udelay(1); if (num_online_cpus() > 1) pr_warning("SMP: failed to stop secondary CPUs\n"); } /* * not supported here */ int setup_profiling_timer(unsigned int multiplier) { return -EINVAL; } #ifdef CONFIG_CPU_FREQ static DEFINE_PER_CPU(unsigned long, l_p_j_ref); static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); static unsigned long global_l_p_j_ref; static unsigned long global_l_p_j_ref_freq; static int cpufreq_callback(struct notifier_block *nb, unsigned long val, void *data) { struct cpufreq_freqs *freq = data; int cpu = freq->cpu; if (freq->flags & CPUFREQ_CONST_LOOPS) return NOTIFY_OK; if (!per_cpu(l_p_j_ref, cpu)) { per_cpu(l_p_j_ref, cpu) = per_cpu(cpu_data, cpu).loops_per_jiffy; per_cpu(l_p_j_ref_freq, cpu) = freq->old; if (!global_l_p_j_ref) { global_l_p_j_ref = loops_per_jiffy; global_l_p_j_ref_freq = freq->old; } } if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) || (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) { loops_per_jiffy = cpufreq_scale(global_l_p_j_ref, global_l_p_j_ref_freq, freq->new); per_cpu(cpu_data, cpu).loops_per_jiffy = cpufreq_scale(per_cpu(l_p_j_ref, cpu), per_cpu(l_p_j_ref_freq, cpu), freq->new); } return NOTIFY_OK; } static struct notifier_block cpufreq_notifier = { .notifier_call = cpufreq_callback, }; static int __init register_cpufreq_notifier(void) { return cpufreq_register_notifier(&cpufreq_notifier, CPUFREQ_TRANSITION_NOTIFIER); } core_initcall(register_cpufreq_notifier); #endif