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/smp_plat.h>
46 #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 pen_release = -1;
72 static DECLARE_COMPLETION(cpu_running);
74 static struct smp_operations smp_ops;
76 void __init smp_set_ops(struct smp_operations *ops)
82 static unsigned long get_arch_pgd(pgd_t *pgd)
84 phys_addr_t pgdir = virt_to_phys(pgd);
85 BUG_ON(pgdir & ARCH_PGD_MASK);
86 return pgdir >> ARCH_PGD_SHIFT;
89 int __cpu_up(unsigned int cpu, struct task_struct *idle)
94 * We need to tell the secondary core where to find
95 * its stack and the page tables.
97 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
99 secondary_data.mpu_rgn_szr = mpu_rgn_info.rgns[MPU_RAM_REGION].drsr;
103 secondary_data.pgdir = get_arch_pgd(idmap_pgd);
104 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
106 __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
107 outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
110 * Now bring the CPU into our world.
112 ret = boot_secondary(cpu, idle);
115 * CPU was successfully started, wait for it
116 * to come online or time out.
118 wait_for_completion_timeout(&cpu_running,
119 msecs_to_jiffies(1000));
121 if (!cpu_online(cpu)) {
122 pr_crit("CPU%u: failed to come online\n", cpu);
126 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
130 memset(&secondary_data, 0, sizeof(secondary_data));
134 /* platform specific SMP operations */
135 void __init smp_init_cpus(void)
137 if (smp_ops.smp_init_cpus)
138 smp_ops.smp_init_cpus();
141 int boot_secondary(unsigned int cpu, struct task_struct *idle)
143 if (smp_ops.smp_boot_secondary)
144 return smp_ops.smp_boot_secondary(cpu, idle);
148 int platform_can_cpu_hotplug(void)
150 #ifdef CONFIG_HOTPLUG_CPU
151 if (smp_ops.cpu_kill)
158 #ifdef CONFIG_HOTPLUG_CPU
159 static int platform_cpu_kill(unsigned int cpu)
161 if (smp_ops.cpu_kill)
162 return smp_ops.cpu_kill(cpu);
166 static int platform_cpu_disable(unsigned int cpu)
168 if (smp_ops.cpu_disable)
169 return smp_ops.cpu_disable(cpu);
172 * By default, allow disabling all CPUs except the first one,
173 * since this is special on a lot of platforms, e.g. because
174 * of clock tick interrupts.
176 return cpu == 0 ? -EPERM : 0;
179 * __cpu_disable runs on the processor to be shutdown.
181 int __cpu_disable(void)
183 unsigned int cpu = smp_processor_id();
186 ret = platform_cpu_disable(cpu);
191 * Take this CPU offline. Once we clear this, we can't return,
192 * and we must not schedule until we're ready to give up the cpu.
194 set_cpu_online(cpu, false);
197 * OK - migrate IRQs away from this CPU
202 * Flush user cache and TLB mappings, and then remove this CPU
203 * from the vm mask set of all processes.
205 * Caches are flushed to the Level of Unification Inner Shareable
206 * to write-back dirty lines to unified caches shared by all CPUs.
209 local_flush_tlb_all();
211 clear_tasks_mm_cpumask(cpu);
216 static DECLARE_COMPLETION(cpu_died);
219 * called on the thread which is asking for a CPU to be shutdown -
220 * waits until shutdown has completed, or it is timed out.
222 void __cpu_die(unsigned int cpu)
224 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
225 pr_err("CPU%u: cpu didn't die\n", cpu);
228 printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
231 * platform_cpu_kill() is generally expected to do the powering off
232 * and/or cutting of clocks to the dying CPU. Optionally, this may
233 * be done by the CPU which is dying in preference to supporting
234 * this call, but that means there is _no_ synchronisation between
235 * the requesting CPU and the dying CPU actually losing power.
237 if (!platform_cpu_kill(cpu))
238 printk("CPU%u: unable to kill\n", cpu);
242 * Called from the idle thread for the CPU which has been shutdown.
244 * Note that we disable IRQs here, but do not re-enable them
245 * before returning to the caller. This is also the behaviour
246 * of the other hotplug-cpu capable cores, so presumably coming
247 * out of idle fixes this.
249 void __ref cpu_die(void)
251 unsigned int cpu = smp_processor_id();
258 * Flush the data out of the L1 cache for this CPU. This must be
259 * before the completion to ensure that data is safely written out
260 * before platform_cpu_kill() gets called - which may disable
261 * *this* CPU and power down its cache.
266 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
267 * this returns, power and/or clocks can be removed at any point
268 * from this CPU and its cache by platform_cpu_kill().
273 * Ensure that the cache lines associated with that completion are
274 * written out. This covers the case where _this_ CPU is doing the
275 * powering down, to ensure that the completion is visible to the
276 * CPU waiting for this one.
281 * The actual CPU shutdown procedure is at least platform (if not
282 * CPU) specific. This may remove power, or it may simply spin.
284 * Platforms are generally expected *NOT* to return from this call,
285 * although there are some which do because they have no way to
286 * power down the CPU. These platforms are the _only_ reason we
287 * have a return path which uses the fragment of assembly below.
289 * The return path should not be used for platforms which can
293 smp_ops.cpu_die(cpu);
296 * Do not return to the idle loop - jump back to the secondary
297 * cpu initialisation. There's some initialisation which needs
298 * to be repeated to undo the effects of taking the CPU offline.
300 __asm__("mov sp, %0\n"
302 " b secondary_start_kernel"
304 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
306 #endif /* CONFIG_HOTPLUG_CPU */
309 * Called by both boot and secondaries to move global data into
310 * per-processor storage.
312 static void smp_store_cpu_info(unsigned int cpuid)
314 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
316 cpu_info->loops_per_jiffy = loops_per_jiffy;
317 cpu_info->cpuid = read_cpuid_id();
319 store_cpu_topology(cpuid);
323 * This is the secondary CPU boot entry. We're using this CPUs
324 * idle thread stack, but a set of temporary page tables.
326 asmlinkage void secondary_start_kernel(void)
328 struct mm_struct *mm = &init_mm;
332 * The identity mapping is uncached (strongly ordered), so
333 * switch away from it before attempting any exclusive accesses.
335 cpu_switch_mm(mm->pgd, mm);
336 local_flush_bp_all();
337 enter_lazy_tlb(mm, current);
338 local_flush_tlb_all();
341 * All kernel threads share the same mm context; grab a
342 * reference and switch to it.
344 cpu = smp_processor_id();
345 atomic_inc(&mm->mm_count);
346 current->active_mm = mm;
347 cpumask_set_cpu(cpu, mm_cpumask(mm));
351 printk("CPU%u: Booted secondary processor\n", cpu);
354 trace_hardirqs_off();
357 * Give the platform a chance to do its own initialisation.
359 if (smp_ops.smp_secondary_init)
360 smp_ops.smp_secondary_init(cpu);
362 notify_cpu_starting(cpu);
366 smp_store_cpu_info(cpu);
369 * OK, now it's safe to let the boot CPU continue. Wait for
370 * the CPU migration code to notice that the CPU is online
371 * before we continue - which happens after __cpu_up returns.
373 set_cpu_online(cpu, true);
374 complete(&cpu_running);
380 * OK, it's off to the idle thread for us
382 cpu_startup_entry(CPUHP_ONLINE);
385 void __init smp_cpus_done(unsigned int max_cpus)
387 printk(KERN_INFO "SMP: Total of %d processors activated.\n",
393 void __init smp_prepare_boot_cpu(void)
395 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
398 void __init smp_prepare_cpus(unsigned int max_cpus)
400 unsigned int ncores = num_possible_cpus();
404 smp_store_cpu_info(smp_processor_id());
407 * are we trying to boot more cores than exist?
409 if (max_cpus > ncores)
411 if (ncores > 1 && max_cpus) {
413 * Initialise the present map, which describes the set of CPUs
414 * actually populated at the present time. A platform should
415 * re-initialize the map in the platforms smp_prepare_cpus()
416 * if present != possible (e.g. physical hotplug).
418 init_cpu_present(cpu_possible_mask);
421 * Initialise the SCU if there are more than one CPU
422 * and let them know where to start.
424 if (smp_ops.smp_prepare_cpus)
425 smp_ops.smp_prepare_cpus(max_cpus);
429 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
431 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
437 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
439 smp_cross_call(mask, IPI_CALL_FUNC);
442 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
444 smp_cross_call(mask, IPI_WAKEUP);
447 void arch_send_call_function_single_ipi(int cpu)
449 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
452 static const char *ipi_types[NR_IPI] = {
453 #define S(x,s) [x] = s
454 S(IPI_WAKEUP, "CPU wakeup interrupts"),
455 S(IPI_TIMER, "Timer broadcast interrupts"),
456 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
457 S(IPI_CALL_FUNC, "Function call interrupts"),
458 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
459 S(IPI_CPU_STOP, "CPU stop interrupts"),
460 S(IPI_COMPLETION, "completion interrupts"),
463 void show_ipi_list(struct seq_file *p, int prec)
467 for (i = 0; i < NR_IPI; i++) {
468 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
470 for_each_online_cpu(cpu)
471 seq_printf(p, "%10u ",
472 __get_irq_stat(cpu, ipi_irqs[i]));
474 seq_printf(p, " %s\n", ipi_types[i]);
478 u64 smp_irq_stat_cpu(unsigned int cpu)
483 for (i = 0; i < NR_IPI; i++)
484 sum += __get_irq_stat(cpu, ipi_irqs[i]);
489 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
490 void tick_broadcast(const struct cpumask *mask)
492 smp_cross_call(mask, IPI_TIMER);
496 static DEFINE_RAW_SPINLOCK(stop_lock);
499 * ipi_cpu_stop - handle IPI from smp_send_stop()
501 static void ipi_cpu_stop(unsigned int cpu)
503 if (system_state == SYSTEM_BOOTING ||
504 system_state == SYSTEM_RUNNING) {
505 raw_spin_lock(&stop_lock);
506 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
508 raw_spin_unlock(&stop_lock);
511 set_cpu_online(cpu, false);
520 static DEFINE_PER_CPU(struct completion *, cpu_completion);
522 int register_ipi_completion(struct completion *completion, int cpu)
524 per_cpu(cpu_completion, cpu) = completion;
525 return IPI_COMPLETION;
528 static void ipi_complete(unsigned int cpu)
530 complete(per_cpu(cpu_completion, cpu));
534 * Main handler for inter-processor interrupts
536 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
538 handle_IPI(ipinr, regs);
541 void handle_IPI(int ipinr, struct pt_regs *regs)
543 unsigned int cpu = smp_processor_id();
544 struct pt_regs *old_regs = set_irq_regs(regs);
547 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
553 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
556 tick_receive_broadcast();
567 generic_smp_call_function_interrupt();
571 case IPI_CALL_FUNC_SINGLE:
573 generic_smp_call_function_single_interrupt();
590 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
594 set_irq_regs(old_regs);
597 void smp_send_reschedule(int cpu)
599 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
602 void smp_send_stop(void)
604 unsigned long timeout;
607 cpumask_copy(&mask, cpu_online_mask);
608 cpumask_clear_cpu(smp_processor_id(), &mask);
609 if (!cpumask_empty(&mask))
610 smp_cross_call(&mask, IPI_CPU_STOP);
612 /* Wait up to one second for other CPUs to stop */
613 timeout = USEC_PER_SEC;
614 while (num_online_cpus() > 1 && timeout--)
617 if (num_online_cpus() > 1)
618 pr_warning("SMP: failed to stop secondary CPUs\n");
624 int setup_profiling_timer(unsigned int multiplier)
629 #ifdef CONFIG_CPU_FREQ
631 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
632 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
633 static unsigned long global_l_p_j_ref;
634 static unsigned long global_l_p_j_ref_freq;
636 static int cpufreq_callback(struct notifier_block *nb,
637 unsigned long val, void *data)
639 struct cpufreq_freqs *freq = data;
642 if (freq->flags & CPUFREQ_CONST_LOOPS)
645 if (!per_cpu(l_p_j_ref, cpu)) {
646 per_cpu(l_p_j_ref, cpu) =
647 per_cpu(cpu_data, cpu).loops_per_jiffy;
648 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
649 if (!global_l_p_j_ref) {
650 global_l_p_j_ref = loops_per_jiffy;
651 global_l_p_j_ref_freq = freq->old;
655 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
656 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
657 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
658 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
659 global_l_p_j_ref_freq,
661 per_cpu(cpu_data, cpu).loops_per_jiffy =
662 cpufreq_scale(per_cpu(l_p_j_ref, cpu),
663 per_cpu(l_p_j_ref_freq, cpu),
669 static struct notifier_block cpufreq_notifier = {
670 .notifier_call = cpufreq_callback,
673 static int __init register_cpufreq_notifier(void)
675 return cpufreq_register_notifier(&cpufreq_notifier,
676 CPUFREQ_TRANSITION_NOTIFIER);
678 core_initcall(register_cpufreq_notifier);