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/smp.h>
23 #include <linux/seq_file.h>
24 #include <linux/irq.h>
25 #include <linux/percpu.h>
26 #include <linux/clockchips.h>
27 #include <linux/completion.h>
29 #include <linux/atomic.h>
30 #include <asm/cacheflush.h>
32 #include <asm/cputype.h>
33 #include <asm/exception.h>
34 #include <asm/idmap.h>
35 #include <asm/topology.h>
36 #include <asm/mmu_context.h>
37 #include <asm/pgtable.h>
38 #include <asm/pgalloc.h>
39 #include <asm/processor.h>
40 #include <asm/sections.h>
41 #include <asm/tlbflush.h>
42 #include <asm/ptrace.h>
43 #include <asm/localtimer.h>
44 #include <asm/smp_plat.h>
48 * as from 2.5, kernels no longer have an init_tasks structure
49 * so we need some other way of telling a new secondary core
50 * where to place its SVC stack
52 struct secondary_data secondary_data;
62 static DECLARE_COMPLETION(cpu_running);
64 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
69 * We need to tell the secondary core where to find
70 * its stack and the page tables.
72 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
73 secondary_data.pgdir = virt_to_phys(idmap_pgd);
74 secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
75 __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
76 outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
79 * Now bring the CPU into our world.
81 ret = boot_secondary(cpu, idle);
84 * CPU was successfully started, wait for it
85 * to come online or time out.
87 wait_for_completion_timeout(&cpu_running,
88 msecs_to_jiffies(1000));
90 if (!cpu_online(cpu)) {
91 pr_crit("CPU%u: failed to come online\n", cpu);
95 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
98 secondary_data.stack = NULL;
99 secondary_data.pgdir = 0;
104 #ifdef CONFIG_HOTPLUG_CPU
105 static void percpu_timer_stop(void);
108 * __cpu_disable runs on the processor to be shutdown.
110 int __cpu_disable(void)
112 unsigned int cpu = smp_processor_id();
115 ret = platform_cpu_disable(cpu);
120 * Take this CPU offline. Once we clear this, we can't return,
121 * and we must not schedule until we're ready to give up the cpu.
123 set_cpu_online(cpu, false);
126 * OK - migrate IRQs away from this CPU
131 * Stop the local timer for this CPU.
136 * Flush user cache and TLB mappings, and then remove this CPU
137 * from the vm mask set of all processes.
139 * Caches are flushed to the Level of Unification Inner Shareable
140 * to write-back dirty lines to unified caches shared by all CPUs.
143 local_flush_tlb_all();
145 clear_tasks_mm_cpumask(cpu);
150 static DECLARE_COMPLETION(cpu_died);
153 * called on the thread which is asking for a CPU to be shutdown -
154 * waits until shutdown has completed, or it is timed out.
156 void __cpu_die(unsigned int cpu)
158 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
159 pr_err("CPU%u: cpu didn't die\n", cpu);
162 printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
164 if (!platform_cpu_kill(cpu))
165 printk("CPU%u: unable to kill\n", cpu);
169 * Called from the idle thread for the CPU which has been shutdown.
171 * Note that we disable IRQs here, but do not re-enable them
172 * before returning to the caller. This is also the behaviour
173 * of the other hotplug-cpu capable cores, so presumably coming
174 * out of idle fixes this.
176 void __ref cpu_die(void)
178 unsigned int cpu = smp_processor_id();
185 /* Tell __cpu_die() that this CPU is now safe to dispose of */
186 RCU_NONIDLE(complete(&cpu_died));
189 * actual CPU shutdown procedure is at least platform (if not
192 platform_cpu_die(cpu);
195 * Do not return to the idle loop - jump back to the secondary
196 * cpu initialisation. There's some initialisation which needs
197 * to be repeated to undo the effects of taking the CPU offline.
199 __asm__("mov sp, %0\n"
201 " b secondary_start_kernel"
203 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
205 #endif /* CONFIG_HOTPLUG_CPU */
208 * Called by both boot and secondaries to move global data into
209 * per-processor storage.
211 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
213 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
215 cpu_info->loops_per_jiffy = loops_per_jiffy;
217 store_cpu_topology(cpuid);
220 static void percpu_timer_setup(void);
223 * This is the secondary CPU boot entry. We're using this CPUs
224 * idle thread stack, but a set of temporary page tables.
226 asmlinkage void __cpuinit secondary_start_kernel(void)
228 struct mm_struct *mm = &init_mm;
229 unsigned int cpu = smp_processor_id();
232 * All kernel threads share the same mm context; grab a
233 * reference and switch to it.
235 atomic_inc(&mm->mm_count);
236 current->active_mm = mm;
237 cpumask_set_cpu(cpu, mm_cpumask(mm));
238 cpu_switch_mm(mm->pgd, mm);
239 enter_lazy_tlb(mm, current);
240 local_flush_tlb_all();
242 printk("CPU%u: Booted secondary processor\n", cpu);
246 trace_hardirqs_off();
249 * Give the platform a chance to do its own initialisation.
251 platform_secondary_init(cpu);
253 notify_cpu_starting(cpu);
257 smp_store_cpu_info(cpu);
260 * OK, now it's safe to let the boot CPU continue. Wait for
261 * the CPU migration code to notice that the CPU is online
262 * before we continue - which happens after __cpu_up returns.
264 set_cpu_online(cpu, true);
265 complete(&cpu_running);
268 * Setup the percpu timer for this CPU.
270 percpu_timer_setup();
276 * OK, it's off to the idle thread for us
281 void __init smp_cpus_done(unsigned int max_cpus)
284 unsigned long bogosum = 0;
286 for_each_online_cpu(cpu)
287 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
289 printk(KERN_INFO "SMP: Total of %d processors activated "
290 "(%lu.%02lu BogoMIPS).\n",
292 bogosum / (500000/HZ),
293 (bogosum / (5000/HZ)) % 100);
298 void __init smp_prepare_boot_cpu(void)
302 void __init smp_prepare_cpus(unsigned int max_cpus)
304 unsigned int ncores = num_possible_cpus();
308 smp_store_cpu_info(smp_processor_id());
311 * are we trying to boot more cores than exist?
313 if (max_cpus > ncores)
315 if (ncores > 1 && max_cpus) {
317 * Enable the local timer or broadcast device for the
318 * boot CPU, but only if we have more than one CPU.
320 percpu_timer_setup();
323 * Initialise the present map, which describes the set of CPUs
324 * actually populated at the present time. A platform should
325 * re-initialize the map in platform_smp_prepare_cpus() if
326 * present != possible (e.g. physical hotplug).
328 init_cpu_present(cpu_possible_mask);
331 * Initialise the SCU if there are more than one CPU
332 * and let them know where to start.
334 platform_smp_prepare_cpus(max_cpus);
338 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
340 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
345 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
347 smp_cross_call(mask, IPI_CALL_FUNC);
350 void arch_send_call_function_single_ipi(int cpu)
352 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
355 static const char *ipi_types[NR_IPI] = {
356 #define S(x,s) [x - IPI_TIMER] = s
357 S(IPI_TIMER, "Timer broadcast interrupts"),
358 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
359 S(IPI_CALL_FUNC, "Function call interrupts"),
360 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
361 S(IPI_CPU_STOP, "CPU stop interrupts"),
364 void show_ipi_list(struct seq_file *p, int prec)
368 for (i = 0; i < NR_IPI; i++) {
369 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
371 for_each_present_cpu(cpu)
372 seq_printf(p, "%10u ",
373 __get_irq_stat(cpu, ipi_irqs[i]));
375 seq_printf(p, " %s\n", ipi_types[i]);
379 u64 smp_irq_stat_cpu(unsigned int cpu)
384 for (i = 0; i < NR_IPI; i++)
385 sum += __get_irq_stat(cpu, ipi_irqs[i]);
391 * Timer (local or broadcast) support
393 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
395 static void ipi_timer(void)
397 struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
398 evt->event_handler(evt);
401 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
402 static void smp_timer_broadcast(const struct cpumask *mask)
404 smp_cross_call(mask, IPI_TIMER);
407 #define smp_timer_broadcast NULL
410 static void broadcast_timer_set_mode(enum clock_event_mode mode,
411 struct clock_event_device *evt)
415 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
417 evt->name = "dummy_timer";
418 evt->features = CLOCK_EVT_FEAT_ONESHOT |
419 CLOCK_EVT_FEAT_PERIODIC |
420 CLOCK_EVT_FEAT_DUMMY;
423 evt->set_mode = broadcast_timer_set_mode;
425 clockevents_register_device(evt);
428 static struct local_timer_ops *lt_ops;
430 #ifdef CONFIG_LOCAL_TIMERS
431 int local_timer_register(struct local_timer_ops *ops)
433 if (!is_smp() || !setup_max_cpus)
444 static void __cpuinit percpu_timer_setup(void)
446 unsigned int cpu = smp_processor_id();
447 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
449 evt->cpumask = cpumask_of(cpu);
450 evt->broadcast = smp_timer_broadcast;
452 if (!lt_ops || lt_ops->setup(evt))
453 broadcast_timer_setup(evt);
456 #ifdef CONFIG_HOTPLUG_CPU
458 * The generic clock events code purposely does not stop the local timer
459 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
462 static void percpu_timer_stop(void)
464 unsigned int cpu = smp_processor_id();
465 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
472 static DEFINE_RAW_SPINLOCK(stop_lock);
475 * ipi_cpu_stop - handle IPI from smp_send_stop()
477 static void ipi_cpu_stop(unsigned int cpu)
479 if (system_state == SYSTEM_BOOTING ||
480 system_state == SYSTEM_RUNNING) {
481 raw_spin_lock(&stop_lock);
482 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
484 raw_spin_unlock(&stop_lock);
487 set_cpu_online(cpu, false);
497 * Main handler for inter-processor interrupts
499 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
501 handle_IPI(ipinr, regs);
504 void handle_IPI(int ipinr, struct pt_regs *regs)
506 unsigned int cpu = smp_processor_id();
507 struct pt_regs *old_regs = set_irq_regs(regs);
509 if (ipinr >= IPI_TIMER && ipinr < IPI_TIMER + NR_IPI)
510 __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_TIMER]);
525 generic_smp_call_function_interrupt();
529 case IPI_CALL_FUNC_SINGLE:
531 generic_smp_call_function_single_interrupt();
542 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
546 set_irq_regs(old_regs);
549 void smp_send_reschedule(int cpu)
551 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
554 #ifdef CONFIG_HOTPLUG_CPU
555 static void smp_kill_cpus(cpumask_t *mask)
558 for_each_cpu(cpu, mask)
559 platform_cpu_kill(cpu);
562 static void smp_kill_cpus(cpumask_t *mask) { }
565 void smp_send_stop(void)
567 unsigned long timeout;
570 cpumask_copy(&mask, cpu_online_mask);
571 cpumask_clear_cpu(smp_processor_id(), &mask);
572 if (!cpumask_empty(&mask))
573 smp_cross_call(&mask, IPI_CPU_STOP);
575 /* Wait up to one second for other CPUs to stop */
576 timeout = USEC_PER_SEC;
577 while (num_online_cpus() > 1 && timeout--)
580 if (num_online_cpus() > 1)
581 pr_warning("SMP: failed to stop secondary CPUs\n");
583 smp_kill_cpus(&mask);
589 int setup_profiling_timer(unsigned int multiplier)