2 * linux/arch/arm/kernel/smp.c
4 * Copyright (C) 2002 ARM Limited, All Rights Reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 #include <linux/module.h>
11 #include <linux/delay.h>
12 #include <linux/init.h>
13 #include <linux/spinlock.h>
14 #include <linux/sched.h>
15 #include <linux/interrupt.h>
16 #include <linux/cache.h>
17 #include <linux/profile.h>
18 #include <linux/errno.h>
20 #include <linux/err.h>
21 #include <linux/cpu.h>
22 #include <linux/seq_file.h>
23 #include <linux/irq.h>
24 #include <linux/percpu.h>
25 #include <linux/clockchips.h>
26 #include <linux/completion.h>
27 #include <linux/cpufreq.h>
29 #include <linux/atomic.h>
31 #include <asm/cacheflush.h>
33 #include <asm/cputype.h>
34 #include <asm/exception.h>
35 #include <asm/idmap.h>
36 #include <asm/topology.h>
37 #include <asm/mmu_context.h>
38 #include <asm/pgtable.h>
39 #include <asm/pgalloc.h>
40 #include <asm/processor.h>
41 #include <asm/sections.h>
42 #include <asm/tlbflush.h>
43 #include <asm/ptrace.h>
44 #include <asm/localtimer.h>
45 #include <asm/smp_plat.h>
46 #include <asm/mach/arch.h>
49 * as from 2.5, kernels no longer have an init_tasks structure
50 * so we need some other way of telling a new secondary core
51 * where to place its SVC stack
53 struct secondary_data secondary_data;
56 * control for which core is the next to come out of the secondary
59 volatile int __cpuinitdata pen_release = -1;
69 static DECLARE_COMPLETION(cpu_running);
71 static struct smp_operations smp_ops;
73 void __init smp_set_ops(struct smp_operations *ops)
79 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
84 * We need to tell the secondary core where to find
85 * its stack and the page tables.
87 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
88 secondary_data.pgdir = virt_to_phys(idmap_pgd);
89 secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
90 __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
91 outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
94 * Now bring the CPU into our world.
96 ret = boot_secondary(cpu, idle);
99 * CPU was successfully started, wait for it
100 * to come online or time out.
102 wait_for_completion_timeout(&cpu_running,
103 msecs_to_jiffies(1000));
105 if (!cpu_online(cpu)) {
106 pr_crit("CPU%u: failed to come online\n", cpu);
110 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
113 secondary_data.stack = NULL;
114 secondary_data.pgdir = 0;
119 /* platform specific SMP operations */
120 void __init smp_init_cpus(void)
122 if (smp_ops.smp_init_cpus)
123 smp_ops.smp_init_cpus();
126 static void __init platform_smp_prepare_cpus(unsigned int max_cpus)
128 if (smp_ops.smp_prepare_cpus)
129 smp_ops.smp_prepare_cpus(max_cpus);
132 static void __cpuinit platform_secondary_init(unsigned int cpu)
134 if (smp_ops.smp_secondary_init)
135 smp_ops.smp_secondary_init(cpu);
138 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
140 if (smp_ops.smp_boot_secondary)
141 return smp_ops.smp_boot_secondary(cpu, idle);
145 #ifdef CONFIG_HOTPLUG_CPU
146 static void percpu_timer_stop(void);
148 static int platform_cpu_kill(unsigned int cpu)
150 if (smp_ops.cpu_kill)
151 return smp_ops.cpu_kill(cpu);
155 static void platform_cpu_die(unsigned int cpu)
158 smp_ops.cpu_die(cpu);
161 static int platform_cpu_disable(unsigned int cpu)
163 if (smp_ops.cpu_disable)
164 return smp_ops.cpu_disable(cpu);
167 * By default, allow disabling all CPUs except the first one,
168 * since this is special on a lot of platforms, e.g. because
169 * of clock tick interrupts.
171 return cpu == 0 ? -EPERM : 0;
174 * __cpu_disable runs on the processor to be shutdown.
176 int __cpuinit __cpu_disable(void)
178 unsigned int cpu = smp_processor_id();
181 ret = platform_cpu_disable(cpu);
186 * Take this CPU offline. Once we clear this, we can't return,
187 * and we must not schedule until we're ready to give up the cpu.
189 set_cpu_online(cpu, false);
192 * OK - migrate IRQs away from this CPU
197 * Stop the local timer for this CPU.
202 * Flush user cache and TLB mappings, and then remove this CPU
203 * from the vm mask set of all processes.
206 local_flush_tlb_all();
208 clear_tasks_mm_cpumask(cpu);
213 static DECLARE_COMPLETION(cpu_died);
216 * called on the thread which is asking for a CPU to be shutdown -
217 * waits until shutdown has completed, or it is timed out.
219 void __cpuinit __cpu_die(unsigned int cpu)
221 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
222 pr_err("CPU%u: cpu didn't die\n", cpu);
225 printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
227 if (!platform_cpu_kill(cpu))
228 printk("CPU%u: unable to kill\n", cpu);
232 * Called from the idle thread for the CPU which has been shutdown.
234 * Note that we disable IRQs here, but do not re-enable them
235 * before returning to the caller. This is also the behaviour
236 * of the other hotplug-cpu capable cores, so presumably coming
237 * out of idle fixes this.
239 void __ref cpu_die(void)
241 unsigned int cpu = smp_processor_id();
248 /* Tell __cpu_die() that this CPU is now safe to dispose of */
249 RCU_NONIDLE(complete(&cpu_died));
252 * actual CPU shutdown procedure is at least platform (if not
255 platform_cpu_die(cpu);
258 * Do not return to the idle loop - jump back to the secondary
259 * cpu initialisation. There's some initialisation which needs
260 * to be repeated to undo the effects of taking the CPU offline.
262 __asm__("mov sp, %0\n"
264 " b secondary_start_kernel"
266 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
268 #endif /* CONFIG_HOTPLUG_CPU */
271 * Called by both boot and secondaries to move global data into
272 * per-processor storage.
274 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
276 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
278 cpu_info->loops_per_jiffy = loops_per_jiffy;
280 store_cpu_topology(cpuid);
283 static void percpu_timer_setup(void);
286 * This is the secondary CPU boot entry. We're using this CPUs
287 * idle thread stack, but a set of temporary page tables.
289 asmlinkage void __cpuinit secondary_start_kernel(void)
291 struct mm_struct *mm = &init_mm;
292 unsigned int cpu = smp_processor_id();
295 * All kernel threads share the same mm context; grab a
296 * reference and switch to it.
298 atomic_inc(&mm->mm_count);
299 current->active_mm = mm;
300 cpumask_set_cpu(cpu, mm_cpumask(mm));
301 cpu_switch_mm(mm->pgd, mm);
302 enter_lazy_tlb(mm, current);
303 local_flush_tlb_all();
305 printk("CPU%u: Booted secondary processor\n", cpu);
309 trace_hardirqs_off();
312 * Give the platform a chance to do its own initialisation.
314 platform_secondary_init(cpu);
316 notify_cpu_starting(cpu);
320 smp_store_cpu_info(cpu);
323 * OK, now it's safe to let the boot CPU continue. Wait for
324 * the CPU migration code to notice that the CPU is online
325 * before we continue - which happens after __cpu_up returns.
327 set_cpu_online(cpu, true);
328 complete(&cpu_running);
331 * Setup the percpu timer for this CPU.
333 percpu_timer_setup();
339 * OK, it's off to the idle thread for us
344 void __init smp_cpus_done(unsigned int max_cpus)
347 unsigned long bogosum = 0;
349 for_each_online_cpu(cpu)
350 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
352 printk(KERN_INFO "SMP: Total of %d processors activated "
353 "(%lu.%02lu BogoMIPS).\n",
355 bogosum / (500000/HZ),
356 (bogosum / (5000/HZ)) % 100);
359 void __init smp_prepare_boot_cpu(void)
363 void __init smp_prepare_cpus(unsigned int max_cpus)
365 unsigned int ncores = num_possible_cpus();
369 smp_store_cpu_info(smp_processor_id());
372 * are we trying to boot more cores than exist?
374 if (max_cpus > ncores)
376 if (ncores > 1 && max_cpus) {
378 * Enable the local timer or broadcast device for the
379 * boot CPU, but only if we have more than one CPU.
381 percpu_timer_setup();
384 * Initialise the present map, which describes the set of CPUs
385 * actually populated at the present time. A platform should
386 * re-initialize the map in platform_smp_prepare_cpus() if
387 * present != possible (e.g. physical hotplug).
389 init_cpu_present(cpu_possible_mask);
392 * Initialise the SCU if there are more than one CPU
393 * and let them know where to start.
395 platform_smp_prepare_cpus(max_cpus);
399 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
401 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
406 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
408 smp_cross_call(mask, IPI_CALL_FUNC);
411 void arch_send_call_function_single_ipi(int cpu)
413 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
416 static const char *ipi_types[NR_IPI] = {
417 #define S(x,s) [x - IPI_TIMER] = s
418 S(IPI_TIMER, "Timer broadcast interrupts"),
419 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
420 S(IPI_CALL_FUNC, "Function call interrupts"),
421 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
422 S(IPI_CPU_STOP, "CPU stop interrupts"),
425 void show_ipi_list(struct seq_file *p, int prec)
429 for (i = 0; i < NR_IPI; i++) {
430 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
432 for_each_present_cpu(cpu)
433 seq_printf(p, "%10u ",
434 __get_irq_stat(cpu, ipi_irqs[i]));
436 seq_printf(p, " %s\n", ipi_types[i]);
440 u64 smp_irq_stat_cpu(unsigned int cpu)
445 for (i = 0; i < NR_IPI; i++)
446 sum += __get_irq_stat(cpu, ipi_irqs[i]);
452 * Timer (local or broadcast) support
454 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
456 static void ipi_timer(void)
458 struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
459 evt->event_handler(evt);
462 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
463 static void smp_timer_broadcast(const struct cpumask *mask)
465 smp_cross_call(mask, IPI_TIMER);
468 #define smp_timer_broadcast NULL
471 static void broadcast_timer_set_mode(enum clock_event_mode mode,
472 struct clock_event_device *evt)
476 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
478 evt->name = "dummy_timer";
479 evt->features = CLOCK_EVT_FEAT_ONESHOT |
480 CLOCK_EVT_FEAT_PERIODIC |
481 CLOCK_EVT_FEAT_DUMMY;
484 evt->set_mode = broadcast_timer_set_mode;
486 clockevents_register_device(evt);
489 static struct local_timer_ops *lt_ops;
491 #ifdef CONFIG_LOCAL_TIMERS
492 int local_timer_register(struct local_timer_ops *ops)
494 if (!is_smp() || !setup_max_cpus)
505 static void __cpuinit percpu_timer_setup(void)
507 unsigned int cpu = smp_processor_id();
508 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
510 evt->cpumask = cpumask_of(cpu);
511 evt->broadcast = smp_timer_broadcast;
513 if (!lt_ops || lt_ops->setup(evt))
514 broadcast_timer_setup(evt);
517 #ifdef CONFIG_HOTPLUG_CPU
519 * The generic clock events code purposely does not stop the local timer
520 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
523 static void percpu_timer_stop(void)
525 unsigned int cpu = smp_processor_id();
526 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
533 static DEFINE_RAW_SPINLOCK(stop_lock);
536 * ipi_cpu_stop - handle IPI from smp_send_stop()
538 static void ipi_cpu_stop(unsigned int cpu)
540 if (system_state == SYSTEM_BOOTING ||
541 system_state == SYSTEM_RUNNING) {
542 raw_spin_lock(&stop_lock);
543 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
545 raw_spin_unlock(&stop_lock);
548 set_cpu_online(cpu, false);
558 * Main handler for inter-processor interrupts
560 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
562 handle_IPI(ipinr, regs);
565 void handle_IPI(int ipinr, struct pt_regs *regs)
567 unsigned int cpu = smp_processor_id();
568 struct pt_regs *old_regs = set_irq_regs(regs);
570 if (ipinr >= IPI_TIMER && ipinr < IPI_TIMER + NR_IPI)
571 __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_TIMER]);
586 generic_smp_call_function_interrupt();
590 case IPI_CALL_FUNC_SINGLE:
592 generic_smp_call_function_single_interrupt();
603 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
607 set_irq_regs(old_regs);
610 void smp_send_reschedule(int cpu)
612 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
615 #ifdef CONFIG_HOTPLUG_CPU
616 static void smp_kill_cpus(cpumask_t *mask)
619 for_each_cpu(cpu, mask)
620 platform_cpu_kill(cpu);
623 static void smp_kill_cpus(cpumask_t *mask) { }
626 void smp_send_stop(void)
628 unsigned long timeout;
631 cpumask_copy(&mask, cpu_online_mask);
632 cpumask_clear_cpu(smp_processor_id(), &mask);
633 if (!cpumask_empty(&mask))
634 smp_cross_call(&mask, IPI_CPU_STOP);
636 /* Wait up to one second for other CPUs to stop */
637 timeout = USEC_PER_SEC;
638 while (num_online_cpus() > 1 && timeout--)
641 if (num_online_cpus() > 1)
642 pr_warning("SMP: failed to stop secondary CPUs\n");
644 smp_kill_cpus(&mask);
650 int setup_profiling_timer(unsigned int multiplier)
655 #ifdef CONFIG_CPU_FREQ
657 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
658 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
659 static unsigned long global_l_p_j_ref;
660 static unsigned long global_l_p_j_ref_freq;
662 static int cpufreq_callback(struct notifier_block *nb,
663 unsigned long val, void *data)
665 struct cpufreq_freqs *freq = data;
668 if (freq->flags & CPUFREQ_CONST_LOOPS)
671 if (!per_cpu(l_p_j_ref, cpu)) {
672 per_cpu(l_p_j_ref, cpu) =
673 per_cpu(cpu_data, cpu).loops_per_jiffy;
674 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
675 if (!global_l_p_j_ref) {
676 global_l_p_j_ref = loops_per_jiffy;
677 global_l_p_j_ref_freq = freq->old;
681 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
682 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
683 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
684 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
685 global_l_p_j_ref_freq,
687 per_cpu(cpu_data, cpu).loops_per_jiffy =
688 cpufreq_scale(per_cpu(l_p_j_ref, cpu),
689 per_cpu(l_p_j_ref_freq, cpu),
695 static struct notifier_block cpufreq_notifier = {
696 .notifier_call = cpufreq_callback,
699 static int __init register_cpufreq_notifier(void)
701 return cpufreq_register_notifier(&cpufreq_notifier,
702 CPUFREQ_TRANSITION_NOTIFIER);
704 core_initcall(register_cpufreq_notifier);