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>
47 #include <asm/mach/arch.h>
50 * as from 2.5, kernels no longer have an init_tasks structure
51 * so we need some other way of telling a new secondary core
52 * where to place its SVC stack
54 struct secondary_data secondary_data;
57 * control for which core is the next to come out of the secondary
60 volatile int __cpuinitdata pen_release = -1;
71 static DECLARE_COMPLETION(cpu_running);
73 static struct smp_operations smp_ops;
75 void __init smp_set_ops(struct smp_operations *ops)
81 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
86 * We need to tell the secondary core where to find
87 * its stack and the page tables.
89 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
90 secondary_data.pgdir = virt_to_phys(idmap_pgd);
91 secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
92 __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
93 outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
96 * Now bring the CPU into our world.
98 ret = boot_secondary(cpu, idle);
101 * CPU was successfully started, wait for it
102 * to come online or time out.
104 wait_for_completion_timeout(&cpu_running,
105 msecs_to_jiffies(1000));
107 if (!cpu_online(cpu)) {
108 pr_crit("CPU%u: failed to come online\n", cpu);
112 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
115 secondary_data.stack = NULL;
116 secondary_data.pgdir = 0;
121 /* platform specific SMP operations */
122 void __init smp_init_cpus(void)
124 if (smp_ops.smp_init_cpus)
125 smp_ops.smp_init_cpus();
128 static void __init platform_smp_prepare_cpus(unsigned int max_cpus)
130 if (smp_ops.smp_prepare_cpus)
131 smp_ops.smp_prepare_cpus(max_cpus);
134 static void __cpuinit platform_secondary_init(unsigned int cpu)
136 if (smp_ops.smp_secondary_init)
137 smp_ops.smp_secondary_init(cpu);
140 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
142 if (smp_ops.smp_boot_secondary)
143 return smp_ops.smp_boot_secondary(cpu, idle);
147 #ifdef CONFIG_HOTPLUG_CPU
148 static void percpu_timer_stop(void);
150 static int platform_cpu_kill(unsigned int cpu)
152 if (smp_ops.cpu_kill)
153 return smp_ops.cpu_kill(cpu);
157 static void platform_cpu_die(unsigned int cpu)
160 smp_ops.cpu_die(cpu);
163 static int platform_cpu_disable(unsigned int cpu)
165 if (smp_ops.cpu_disable)
166 return smp_ops.cpu_disable(cpu);
169 * By default, allow disabling all CPUs except the first one,
170 * since this is special on a lot of platforms, e.g. because
171 * of clock tick interrupts.
173 return cpu == 0 ? -EPERM : 0;
176 * __cpu_disable runs on the processor to be shutdown.
178 int __cpuinit __cpu_disable(void)
180 unsigned int cpu = smp_processor_id();
183 ret = platform_cpu_disable(cpu);
188 * Take this CPU offline. Once we clear this, we can't return,
189 * and we must not schedule until we're ready to give up the cpu.
191 set_cpu_online(cpu, false);
194 * OK - migrate IRQs away from this CPU
199 * Stop the local timer for this CPU.
204 * Flush user cache and TLB mappings, and then remove this CPU
205 * from the vm mask set of all processes.
207 * Caches are flushed to the Level of Unification Inner Shareable
208 * to write-back dirty lines to unified caches shared by all CPUs.
211 local_flush_tlb_all();
213 clear_tasks_mm_cpumask(cpu);
218 static DECLARE_COMPLETION(cpu_died);
221 * called on the thread which is asking for a CPU to be shutdown -
222 * waits until shutdown has completed, or it is timed out.
224 void __cpuinit __cpu_die(unsigned int cpu)
226 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
227 pr_err("CPU%u: cpu didn't die\n", cpu);
230 printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
232 if (!platform_cpu_kill(cpu))
233 printk("CPU%u: unable to kill\n", cpu);
237 * Called from the idle thread for the CPU which has been shutdown.
239 * Note that we disable IRQs here, but do not re-enable them
240 * before returning to the caller. This is also the behaviour
241 * of the other hotplug-cpu capable cores, so presumably coming
242 * out of idle fixes this.
244 void __ref cpu_die(void)
246 unsigned int cpu = smp_processor_id();
253 /* Tell __cpu_die() that this CPU is now safe to dispose of */
254 RCU_NONIDLE(complete(&cpu_died));
257 * actual CPU shutdown procedure is at least platform (if not
260 platform_cpu_die(cpu);
263 * Do not return to the idle loop - jump back to the secondary
264 * cpu initialisation. There's some initialisation which needs
265 * to be repeated to undo the effects of taking the CPU offline.
267 __asm__("mov sp, %0\n"
269 " b secondary_start_kernel"
271 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
273 #endif /* CONFIG_HOTPLUG_CPU */
276 * Called by both boot and secondaries to move global data into
277 * per-processor storage.
279 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
281 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
283 cpu_info->loops_per_jiffy = loops_per_jiffy;
284 cpu_info->cpuid = read_cpuid_id();
286 store_cpu_topology(cpuid);
289 static void percpu_timer_setup(void);
292 * This is the secondary CPU boot entry. We're using this CPUs
293 * idle thread stack, but a set of temporary page tables.
295 asmlinkage void __cpuinit secondary_start_kernel(void)
297 struct mm_struct *mm = &init_mm;
301 * The identity mapping is uncached (strongly ordered), so
302 * switch away from it before attempting any exclusive accesses.
304 cpu_switch_mm(mm->pgd, mm);
305 enter_lazy_tlb(mm, current);
306 local_flush_tlb_all();
309 * All kernel threads share the same mm context; grab a
310 * reference and switch to it.
312 cpu = smp_processor_id();
313 atomic_inc(&mm->mm_count);
314 current->active_mm = mm;
315 cpumask_set_cpu(cpu, mm_cpumask(mm));
319 printk("CPU%u: Booted secondary processor\n", cpu);
322 trace_hardirqs_off();
325 * Give the platform a chance to do its own initialisation.
327 platform_secondary_init(cpu);
329 notify_cpu_starting(cpu);
333 smp_store_cpu_info(cpu);
336 * OK, now it's safe to let the boot CPU continue. Wait for
337 * the CPU migration code to notice that the CPU is online
338 * before we continue - which happens after __cpu_up returns.
340 set_cpu_online(cpu, true);
341 complete(&cpu_running);
344 * Setup the percpu timer for this CPU.
346 percpu_timer_setup();
352 * OK, it's off to the idle thread for us
357 void __init smp_cpus_done(unsigned int max_cpus)
360 unsigned long bogosum = 0;
362 for_each_online_cpu(cpu)
363 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
365 printk(KERN_INFO "SMP: Total of %d processors activated "
366 "(%lu.%02lu BogoMIPS).\n",
368 bogosum / (500000/HZ),
369 (bogosum / (5000/HZ)) % 100);
374 void __init smp_prepare_boot_cpu(void)
376 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
379 void __init smp_prepare_cpus(unsigned int max_cpus)
381 unsigned int ncores = num_possible_cpus();
385 smp_store_cpu_info(smp_processor_id());
388 * are we trying to boot more cores than exist?
390 if (max_cpus > ncores)
392 if (ncores > 1 && max_cpus) {
394 * Enable the local timer or broadcast device for the
395 * boot CPU, but only if we have more than one CPU.
397 percpu_timer_setup();
400 * Initialise the present map, which describes the set of CPUs
401 * actually populated at the present time. A platform should
402 * re-initialize the map in platform_smp_prepare_cpus() if
403 * present != possible (e.g. physical hotplug).
405 init_cpu_present(cpu_possible_mask);
408 * Initialise the SCU if there are more than one CPU
409 * and let them know where to start.
411 platform_smp_prepare_cpus(max_cpus);
415 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
417 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
423 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
425 smp_cross_call(mask, IPI_CALL_FUNC);
428 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
430 smp_cross_call(mask, IPI_WAKEUP);
433 void arch_send_call_function_single_ipi(int cpu)
435 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
438 static const char *ipi_types[NR_IPI] = {
439 #define S(x,s) [x] = s
440 S(IPI_WAKEUP, "CPU wakeup interrupts"),
441 S(IPI_TIMER, "Timer broadcast interrupts"),
442 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
443 S(IPI_CALL_FUNC, "Function call interrupts"),
444 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
445 S(IPI_CPU_STOP, "CPU stop interrupts"),
448 void show_ipi_list(struct seq_file *p, int prec)
452 for (i = 0; i < NR_IPI; i++) {
453 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
455 for_each_online_cpu(cpu)
456 seq_printf(p, "%10u ",
457 __get_irq_stat(cpu, ipi_irqs[i]));
459 seq_printf(p, " %s\n", ipi_types[i]);
463 u64 smp_irq_stat_cpu(unsigned int cpu)
468 for (i = 0; i < NR_IPI; i++)
469 sum += __get_irq_stat(cpu, ipi_irqs[i]);
475 * Timer (local or broadcast) support
477 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
479 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
480 void tick_broadcast(const struct cpumask *mask)
482 smp_cross_call(mask, IPI_TIMER);
485 #define smp_timer_broadcast NULL
488 static void broadcast_timer_set_mode(enum clock_event_mode mode,
489 struct clock_event_device *evt)
493 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
495 evt->name = "dummy_timer";
496 evt->features = CLOCK_EVT_FEAT_ONESHOT |
497 CLOCK_EVT_FEAT_PERIODIC |
498 CLOCK_EVT_FEAT_DUMMY;
501 evt->set_mode = broadcast_timer_set_mode;
503 clockevents_register_device(evt);
506 static struct local_timer_ops *lt_ops;
508 #ifdef CONFIG_LOCAL_TIMERS
509 int local_timer_register(struct local_timer_ops *ops)
511 if (!is_smp() || !setup_max_cpus)
522 static void __cpuinit percpu_timer_setup(void)
524 unsigned int cpu = smp_processor_id();
525 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
527 evt->cpumask = cpumask_of(cpu);
529 if (!lt_ops || lt_ops->setup(evt))
530 broadcast_timer_setup(evt);
533 #ifdef CONFIG_HOTPLUG_CPU
535 * The generic clock events code purposely does not stop the local timer
536 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
539 static void percpu_timer_stop(void)
541 unsigned int cpu = smp_processor_id();
542 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
549 static DEFINE_RAW_SPINLOCK(stop_lock);
552 * ipi_cpu_stop - handle IPI from smp_send_stop()
554 static void ipi_cpu_stop(unsigned int cpu)
556 if (system_state == SYSTEM_BOOTING ||
557 system_state == SYSTEM_RUNNING) {
558 raw_spin_lock(&stop_lock);
559 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
561 raw_spin_unlock(&stop_lock);
564 set_cpu_online(cpu, false);
574 * Main handler for inter-processor interrupts
576 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
578 handle_IPI(ipinr, regs);
581 void handle_IPI(int ipinr, struct pt_regs *regs)
583 unsigned int cpu = smp_processor_id();
584 struct pt_regs *old_regs = set_irq_regs(regs);
587 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
593 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
596 tick_receive_broadcast();
607 generic_smp_call_function_interrupt();
611 case IPI_CALL_FUNC_SINGLE:
613 generic_smp_call_function_single_interrupt();
624 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
628 set_irq_regs(old_regs);
631 void smp_send_reschedule(int cpu)
633 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
636 #ifdef CONFIG_HOTPLUG_CPU
637 static void smp_kill_cpus(cpumask_t *mask)
640 for_each_cpu(cpu, mask)
641 platform_cpu_kill(cpu);
644 static void smp_kill_cpus(cpumask_t *mask) { }
647 void smp_send_stop(void)
649 unsigned long timeout;
652 cpumask_copy(&mask, cpu_online_mask);
653 cpumask_clear_cpu(smp_processor_id(), &mask);
654 if (!cpumask_empty(&mask))
655 smp_cross_call(&mask, IPI_CPU_STOP);
657 /* Wait up to one second for other CPUs to stop */
658 timeout = USEC_PER_SEC;
659 while (num_online_cpus() > 1 && timeout--)
662 if (num_online_cpus() > 1)
663 pr_warning("SMP: failed to stop secondary CPUs\n");
665 smp_kill_cpus(&mask);
671 int setup_profiling_timer(unsigned int multiplier)
676 #ifdef CONFIG_CPU_FREQ
678 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
679 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
680 static unsigned long global_l_p_j_ref;
681 static unsigned long global_l_p_j_ref_freq;
683 static int cpufreq_callback(struct notifier_block *nb,
684 unsigned long val, void *data)
686 struct cpufreq_freqs *freq = data;
689 if (freq->flags & CPUFREQ_CONST_LOOPS)
692 if (!per_cpu(l_p_j_ref, cpu)) {
693 per_cpu(l_p_j_ref, cpu) =
694 per_cpu(cpu_data, cpu).loops_per_jiffy;
695 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
696 if (!global_l_p_j_ref) {
697 global_l_p_j_ref = loops_per_jiffy;
698 global_l_p_j_ref_freq = freq->old;
702 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
703 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
704 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
705 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
706 global_l_p_j_ref_freq,
708 per_cpu(cpu_data, cpu).loops_per_jiffy =
709 cpufreq_scale(per_cpu(l_p_j_ref, cpu),
710 per_cpu(l_p_j_ref_freq, cpu),
716 static struct notifier_block cpufreq_notifier = {
717 .notifier_call = cpufreq_callback,
720 static int __init register_cpufreq_notifier(void)
722 return cpufreq_register_notifier(&cpufreq_notifier,
723 CPUFREQ_TRANSITION_NOTIFIER);
725 core_initcall(register_cpufreq_notifier);