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/nmi.h>
25 #include <linux/percpu.h>
26 #include <linux/clockchips.h>
27 #include <linux/completion.h>
28 #include <linux/cpufreq.h>
29 #include <linux/irq_work.h>
30 #include <linux/slab.h>
32 #include <linux/atomic.h>
35 #include <asm/cacheflush.h>
37 #include <asm/cputype.h>
38 #include <asm/exception.h>
39 #include <asm/idmap.h>
40 #include <asm/topology.h>
41 #include <asm/mmu_context.h>
42 #include <asm/pgtable.h>
43 #include <asm/pgalloc.h>
44 #include <asm/procinfo.h>
45 #include <asm/processor.h>
46 #include <asm/sections.h>
47 #include <asm/tlbflush.h>
48 #include <asm/ptrace.h>
49 #include <asm/smp_plat.h>
51 #include <asm/mach/arch.h>
54 #define CREATE_TRACE_POINTS
55 #include <trace/events/ipi.h>
58 * as from 2.5, kernels no longer have an init_tasks structure
59 * so we need some other way of telling a new secondary core
60 * where to place its SVC stack
62 struct secondary_data secondary_data;
65 * control for which core is the next to come out of the secondary
68 volatile int pen_release = -1;
79 IPI_CPU_BACKTRACE = 15,
82 static DECLARE_COMPLETION(cpu_running);
84 static struct smp_operations smp_ops;
86 void __init smp_set_ops(const struct smp_operations *ops)
92 static unsigned long get_arch_pgd(pgd_t *pgd)
94 #ifdef CONFIG_ARM_LPAE
95 return __phys_to_pfn(virt_to_phys(pgd));
97 return virt_to_phys(pgd);
101 #if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
102 static int secondary_biglittle_prepare(unsigned int cpu)
104 if (!cpu_vtable[cpu])
105 cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL);
107 return cpu_vtable[cpu] ? 0 : -ENOMEM;
110 static void secondary_biglittle_init(void)
112 init_proc_vtable(lookup_processor(read_cpuid_id())->proc);
115 static int secondary_biglittle_prepare(unsigned int cpu)
120 static void secondary_biglittle_init(void)
125 int __cpu_up(unsigned int cpu, struct task_struct *idle)
129 if (!smp_ops.smp_boot_secondary)
132 ret = secondary_biglittle_prepare(cpu);
137 * We need to tell the secondary core where to find
138 * its stack and the page tables.
140 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
141 #ifdef CONFIG_ARM_MPU
142 secondary_data.mpu_rgn_szr = mpu_rgn_info.rgns[MPU_RAM_REGION].drsr;
146 secondary_data.pgdir = virt_to_phys(idmap_pgd);
147 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
149 sync_cache_w(&secondary_data);
152 * Now bring the CPU into our world.
154 ret = smp_ops.smp_boot_secondary(cpu, idle);
157 * CPU was successfully started, wait for it
158 * to come online or time out.
160 wait_for_completion_timeout(&cpu_running,
161 msecs_to_jiffies(1000));
163 if (!cpu_online(cpu)) {
164 pr_crit("CPU%u: failed to come online\n", cpu);
168 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
172 memset(&secondary_data, 0, sizeof(secondary_data));
176 /* platform specific SMP operations */
177 void __init smp_init_cpus(void)
179 if (smp_ops.smp_init_cpus)
180 smp_ops.smp_init_cpus();
183 int platform_can_secondary_boot(void)
185 return !!smp_ops.smp_boot_secondary;
188 int platform_can_cpu_hotplug(void)
190 #ifdef CONFIG_HOTPLUG_CPU
191 if (smp_ops.cpu_kill)
198 #ifdef CONFIG_HOTPLUG_CPU
199 static int platform_cpu_kill(unsigned int cpu)
201 if (smp_ops.cpu_kill)
202 return smp_ops.cpu_kill(cpu);
206 static int platform_cpu_disable(unsigned int cpu)
208 if (smp_ops.cpu_disable)
209 return smp_ops.cpu_disable(cpu);
214 int platform_can_hotplug_cpu(unsigned int cpu)
216 /* cpu_die must be specified to support hotplug */
217 if (!smp_ops.cpu_die)
220 if (smp_ops.cpu_can_disable)
221 return smp_ops.cpu_can_disable(cpu);
224 * By default, allow disabling all CPUs except the first one,
225 * since this is special on a lot of platforms, e.g. because
226 * of clock tick interrupts.
232 * __cpu_disable runs on the processor to be shutdown.
234 int __cpu_disable(void)
236 unsigned int cpu = smp_processor_id();
239 ret = platform_cpu_disable(cpu);
244 * Take this CPU offline. Once we clear this, we can't return,
245 * and we must not schedule until we're ready to give up the cpu.
247 set_cpu_online(cpu, false);
250 * OK - migrate IRQs away from this CPU
252 irq_migrate_all_off_this_cpu();
255 * Flush user cache and TLB mappings, and then remove this CPU
256 * from the vm mask set of all processes.
258 * Caches are flushed to the Level of Unification Inner Shareable
259 * to write-back dirty lines to unified caches shared by all CPUs.
262 local_flush_tlb_all();
264 clear_tasks_mm_cpumask(cpu);
269 static DECLARE_COMPLETION(cpu_died);
272 * called on the thread which is asking for a CPU to be shutdown -
273 * waits until shutdown has completed, or it is timed out.
275 void __cpu_die(unsigned int cpu)
277 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
278 pr_err("CPU%u: cpu didn't die\n", cpu);
281 pr_notice("CPU%u: shutdown\n", cpu);
284 * platform_cpu_kill() is generally expected to do the powering off
285 * and/or cutting of clocks to the dying CPU. Optionally, this may
286 * be done by the CPU which is dying in preference to supporting
287 * this call, but that means there is _no_ synchronisation between
288 * the requesting CPU and the dying CPU actually losing power.
290 if (!platform_cpu_kill(cpu))
291 pr_err("CPU%u: unable to kill\n", cpu);
295 * Called from the idle thread for the CPU which has been shutdown.
297 * Note that we disable IRQs here, but do not re-enable them
298 * before returning to the caller. This is also the behaviour
299 * of the other hotplug-cpu capable cores, so presumably coming
300 * out of idle fixes this.
302 void arch_cpu_idle_dead(void)
304 unsigned int cpu = smp_processor_id();
311 * Flush the data out of the L1 cache for this CPU. This must be
312 * before the completion to ensure that data is safely written out
313 * before platform_cpu_kill() gets called - which may disable
314 * *this* CPU and power down its cache.
319 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
320 * this returns, power and/or clocks can be removed at any point
321 * from this CPU and its cache by platform_cpu_kill().
326 * Ensure that the cache lines associated with that completion are
327 * written out. This covers the case where _this_ CPU is doing the
328 * powering down, to ensure that the completion is visible to the
329 * CPU waiting for this one.
334 * The actual CPU shutdown procedure is at least platform (if not
335 * CPU) specific. This may remove power, or it may simply spin.
337 * Platforms are generally expected *NOT* to return from this call,
338 * although there are some which do because they have no way to
339 * power down the CPU. These platforms are the _only_ reason we
340 * have a return path which uses the fragment of assembly below.
342 * The return path should not be used for platforms which can
346 smp_ops.cpu_die(cpu);
348 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
352 * Do not return to the idle loop - jump back to the secondary
353 * cpu initialisation. There's some initialisation which needs
354 * to be repeated to undo the effects of taking the CPU offline.
356 __asm__("mov sp, %0\n"
358 " b secondary_start_kernel"
360 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
362 #endif /* CONFIG_HOTPLUG_CPU */
365 * Called by both boot and secondaries to move global data into
366 * per-processor storage.
368 static void smp_store_cpu_info(unsigned int cpuid)
370 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
372 cpu_info->loops_per_jiffy = loops_per_jiffy;
373 cpu_info->cpuid = read_cpuid_id();
375 store_cpu_topology(cpuid);
379 * This is the secondary CPU boot entry. We're using this CPUs
380 * idle thread stack, but a set of temporary page tables.
382 asmlinkage void secondary_start_kernel(void)
384 struct mm_struct *mm = &init_mm;
387 secondary_biglittle_init();
390 * The identity mapping is uncached (strongly ordered), so
391 * switch away from it before attempting any exclusive accesses.
393 cpu_switch_mm(mm->pgd, mm);
394 local_flush_bp_all();
395 enter_lazy_tlb(mm, current);
396 local_flush_tlb_all();
399 * All kernel threads share the same mm context; grab a
400 * reference and switch to it.
402 cpu = smp_processor_id();
403 atomic_inc(&mm->mm_count);
404 current->active_mm = mm;
405 cpumask_set_cpu(cpu, mm_cpumask(mm));
409 pr_debug("CPU%u: Booted secondary processor\n", cpu);
412 trace_hardirqs_off();
415 * Give the platform a chance to do its own initialisation.
417 if (smp_ops.smp_secondary_init)
418 smp_ops.smp_secondary_init(cpu);
420 notify_cpu_starting(cpu);
424 smp_store_cpu_info(cpu);
427 * OK, now it's safe to let the boot CPU continue. Wait for
428 * the CPU migration code to notice that the CPU is online
429 * before we continue - which happens after __cpu_up returns.
431 set_cpu_online(cpu, true);
435 complete(&cpu_running);
442 * OK, it's off to the idle thread for us
444 cpu_startup_entry(CPUHP_ONLINE);
447 void __init smp_cpus_done(unsigned int max_cpus)
450 unsigned long bogosum = 0;
452 for_each_online_cpu(cpu)
453 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
455 printk(KERN_INFO "SMP: Total of %d processors activated "
456 "(%lu.%02lu BogoMIPS).\n",
458 bogosum / (500000/HZ),
459 (bogosum / (5000/HZ)) % 100);
464 void __init smp_prepare_boot_cpu(void)
466 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
469 void __init smp_prepare_cpus(unsigned int max_cpus)
471 unsigned int ncores = num_possible_cpus();
475 smp_store_cpu_info(smp_processor_id());
478 * are we trying to boot more cores than exist?
480 if (max_cpus > ncores)
482 if (ncores > 1 && max_cpus) {
484 * Initialise the present map, which describes the set of CPUs
485 * actually populated at the present time. A platform should
486 * re-initialize the map in the platforms smp_prepare_cpus()
487 * if present != possible (e.g. physical hotplug).
489 init_cpu_present(cpu_possible_mask);
492 * Initialise the SCU if there are more than one CPU
493 * and let them know where to start.
495 if (smp_ops.smp_prepare_cpus)
496 smp_ops.smp_prepare_cpus(max_cpus);
500 static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
502 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
504 if (!__smp_cross_call)
505 __smp_cross_call = fn;
508 static const char *ipi_types[NR_IPI] __tracepoint_string = {
509 #define S(x,s) [x] = s
510 S(IPI_WAKEUP, "CPU wakeup interrupts"),
511 S(IPI_TIMER, "Timer broadcast interrupts"),
512 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
513 S(IPI_CALL_FUNC, "Function call interrupts"),
514 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
515 S(IPI_CPU_STOP, "CPU stop interrupts"),
516 S(IPI_IRQ_WORK, "IRQ work interrupts"),
517 S(IPI_COMPLETION, "completion interrupts"),
520 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
522 trace_ipi_raise(target, ipi_types[ipinr]);
523 __smp_cross_call(target, ipinr);
526 void show_ipi_list(struct seq_file *p, int prec)
530 for (i = 0; i < NR_IPI; i++) {
531 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
533 for_each_online_cpu(cpu)
534 seq_printf(p, "%10u ",
535 __get_irq_stat(cpu, ipi_irqs[i]));
537 seq_printf(p, " %s\n", ipi_types[i]);
541 u64 smp_irq_stat_cpu(unsigned int cpu)
546 for (i = 0; i < NR_IPI; i++)
547 sum += __get_irq_stat(cpu, ipi_irqs[i]);
552 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
554 smp_cross_call(mask, IPI_CALL_FUNC);
557 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
559 smp_cross_call(mask, IPI_WAKEUP);
562 void arch_send_call_function_single_ipi(int cpu)
564 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
567 #ifdef CONFIG_IRQ_WORK
568 void arch_irq_work_raise(void)
570 if (arch_irq_work_has_interrupt())
571 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
575 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
576 void tick_broadcast(const struct cpumask *mask)
578 smp_cross_call(mask, IPI_TIMER);
582 static DEFINE_RAW_SPINLOCK(stop_lock);
585 * ipi_cpu_stop - handle IPI from smp_send_stop()
587 static void ipi_cpu_stop(unsigned int cpu)
589 if (system_state == SYSTEM_BOOTING ||
590 system_state == SYSTEM_RUNNING) {
591 raw_spin_lock(&stop_lock);
592 pr_crit("CPU%u: stopping\n", cpu);
594 raw_spin_unlock(&stop_lock);
597 set_cpu_online(cpu, false);
608 static DEFINE_PER_CPU(struct completion *, cpu_completion);
610 int register_ipi_completion(struct completion *completion, int cpu)
612 per_cpu(cpu_completion, cpu) = completion;
613 return IPI_COMPLETION;
616 static void ipi_complete(unsigned int cpu)
618 complete(per_cpu(cpu_completion, cpu));
622 * Main handler for inter-processor interrupts
624 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
626 handle_IPI(ipinr, regs);
629 void handle_IPI(int ipinr, struct pt_regs *regs)
631 unsigned int cpu = smp_processor_id();
632 struct pt_regs *old_regs = set_irq_regs(regs);
634 if ((unsigned)ipinr < NR_IPI) {
635 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
636 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
643 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
646 tick_receive_broadcast();
657 generic_smp_call_function_interrupt();
661 case IPI_CALL_FUNC_SINGLE:
663 generic_smp_call_function_single_interrupt();
673 #ifdef CONFIG_IRQ_WORK
687 case IPI_CPU_BACKTRACE:
689 nmi_cpu_backtrace(regs);
694 pr_crit("CPU%u: Unknown IPI message 0x%x\n",
699 if ((unsigned)ipinr < NR_IPI)
700 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
701 set_irq_regs(old_regs);
704 void smp_send_reschedule(int cpu)
706 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
709 void smp_send_stop(void)
711 unsigned long timeout;
714 cpumask_copy(&mask, cpu_online_mask);
715 cpumask_clear_cpu(smp_processor_id(), &mask);
716 if (!cpumask_empty(&mask))
717 smp_cross_call(&mask, IPI_CPU_STOP);
719 /* Wait up to one second for other CPUs to stop */
720 timeout = USEC_PER_SEC;
721 while (num_online_cpus() > 1 && timeout--)
724 if (num_online_cpus() > 1)
725 pr_warn("SMP: failed to stop secondary CPUs\n");
728 /* In case panic() and panic() called at the same time on CPU1 and CPU2,
729 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
730 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
731 * kdump fails. So split out the panic_smp_self_stop() and add
732 * set_cpu_online(smp_processor_id(), false).
734 void panic_smp_self_stop(void)
736 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
738 set_cpu_online(smp_processor_id(), false);
746 int setup_profiling_timer(unsigned int multiplier)
751 #ifdef CONFIG_CPU_FREQ
753 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
754 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
755 static unsigned long global_l_p_j_ref;
756 static unsigned long global_l_p_j_ref_freq;
758 static int cpufreq_callback(struct notifier_block *nb,
759 unsigned long val, void *data)
761 struct cpufreq_freqs *freq = data;
764 if (freq->flags & CPUFREQ_CONST_LOOPS)
767 if (!per_cpu(l_p_j_ref, cpu)) {
768 per_cpu(l_p_j_ref, cpu) =
769 per_cpu(cpu_data, cpu).loops_per_jiffy;
770 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
771 if (!global_l_p_j_ref) {
772 global_l_p_j_ref = loops_per_jiffy;
773 global_l_p_j_ref_freq = freq->old;
777 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
778 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
779 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
780 global_l_p_j_ref_freq,
782 per_cpu(cpu_data, cpu).loops_per_jiffy =
783 cpufreq_scale(per_cpu(l_p_j_ref, cpu),
784 per_cpu(l_p_j_ref_freq, cpu),
790 static struct notifier_block cpufreq_notifier = {
791 .notifier_call = cpufreq_callback,
794 static int __init register_cpufreq_notifier(void)
796 return cpufreq_register_notifier(&cpufreq_notifier,
797 CPUFREQ_TRANSITION_NOTIFIER);
799 core_initcall(register_cpufreq_notifier);
803 static void raise_nmi(cpumask_t *mask)
806 * Generate the backtrace directly if we are running in a calling
807 * context that is not preemptible by the backtrace IPI. Note
808 * that nmi_cpu_backtrace() automatically removes the current cpu
811 if (cpumask_test_cpu(smp_processor_id(), mask) && irqs_disabled())
812 nmi_cpu_backtrace(NULL);
814 smp_cross_call(mask, IPI_CPU_BACKTRACE);
817 void arch_trigger_all_cpu_backtrace(bool include_self)
819 nmi_trigger_all_cpu_backtrace(include_self, raise_nmi);