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>
47 * as from 2.5, kernels no longer have an init_tasks structure
48 * so we need some other way of telling a new secondary core
49 * where to place its SVC stack
51 struct secondary_data secondary_data;
61 static DECLARE_COMPLETION(cpu_running);
63 int __cpuinit __cpu_up(unsigned int cpu)
65 struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
66 struct task_struct *idle = ci->idle;
70 * Spawn a new process manually, if not already done.
71 * Grab a pointer to its task struct so we can mess with it
74 idle = fork_idle(cpu);
76 printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
82 * Since this idle thread is being re-used, call
83 * init_idle() to reinitialize the thread structure.
89 * We need to tell the secondary core where to find
90 * its stack and the page tables.
92 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
93 secondary_data.pgdir = virt_to_phys(idmap_pgd);
94 secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
95 __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
96 outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
99 * Now bring the CPU into our world.
101 ret = boot_secondary(cpu, idle);
104 * CPU was successfully started, wait for it
105 * to come online or time out.
107 wait_for_completion_timeout(&cpu_running,
108 msecs_to_jiffies(1000));
110 if (!cpu_online(cpu)) {
111 pr_crit("CPU%u: failed to come online\n", cpu);
115 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
118 secondary_data.stack = NULL;
119 secondary_data.pgdir = 0;
124 #ifdef CONFIG_HOTPLUG_CPU
125 static void percpu_timer_stop(void);
128 * __cpu_disable runs on the processor to be shutdown.
130 int __cpu_disable(void)
132 unsigned int cpu = smp_processor_id();
133 struct task_struct *p;
136 ret = platform_cpu_disable(cpu);
141 * Take this CPU offline. Once we clear this, we can't return,
142 * and we must not schedule until we're ready to give up the cpu.
144 set_cpu_online(cpu, false);
147 * OK - migrate IRQs away from this CPU
152 * Stop the local timer for this CPU.
157 * Flush user cache and TLB mappings, and then remove this CPU
158 * from the vm mask set of all processes.
161 local_flush_tlb_all();
163 read_lock(&tasklist_lock);
164 for_each_process(p) {
166 cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
168 read_unlock(&tasklist_lock);
173 static DECLARE_COMPLETION(cpu_died);
176 * called on the thread which is asking for a CPU to be shutdown -
177 * waits until shutdown has completed, or it is timed out.
179 void __cpu_die(unsigned int cpu)
181 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
182 pr_err("CPU%u: cpu didn't die\n", cpu);
185 printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
187 if (!platform_cpu_kill(cpu))
188 printk("CPU%u: unable to kill\n", cpu);
192 * Called from the idle thread for the CPU which has been shutdown.
194 * Note that we disable IRQs here, but do not re-enable them
195 * before returning to the caller. This is also the behaviour
196 * of the other hotplug-cpu capable cores, so presumably coming
197 * out of idle fixes this.
199 void __ref cpu_die(void)
201 unsigned int cpu = smp_processor_id();
208 /* Tell __cpu_die() that this CPU is now safe to dispose of */
212 * actual CPU shutdown procedure is at least platform (if not
215 platform_cpu_die(cpu);
218 * Do not return to the idle loop - jump back to the secondary
219 * cpu initialisation. There's some initialisation which needs
220 * to be repeated to undo the effects of taking the CPU offline.
222 __asm__("mov sp, %0\n"
224 " b secondary_start_kernel"
226 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
228 #endif /* CONFIG_HOTPLUG_CPU */
231 * Called by both boot and secondaries to move global data into
232 * per-processor storage.
234 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
236 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
238 cpu_info->loops_per_jiffy = loops_per_jiffy;
240 store_cpu_topology(cpuid);
243 static void percpu_timer_setup(void);
246 * This is the secondary CPU boot entry. We're using this CPUs
247 * idle thread stack, but a set of temporary page tables.
249 asmlinkage void __cpuinit secondary_start_kernel(void)
251 struct mm_struct *mm = &init_mm;
252 unsigned int cpu = smp_processor_id();
254 printk("CPU%u: Booted secondary processor\n", cpu);
257 * All kernel threads share the same mm context; grab a
258 * reference and switch to it.
260 atomic_inc(&mm->mm_count);
261 current->active_mm = mm;
262 cpumask_set_cpu(cpu, mm_cpumask(mm));
263 cpu_switch_mm(mm->pgd, mm);
264 enter_lazy_tlb(mm, current);
265 local_flush_tlb_all();
269 trace_hardirqs_off();
272 * Give the platform a chance to do its own initialisation.
274 platform_secondary_init(cpu);
276 notify_cpu_starting(cpu);
280 smp_store_cpu_info(cpu);
283 * OK, now it's safe to let the boot CPU continue. Wait for
284 * the CPU migration code to notice that the CPU is online
285 * before we continue - which happens after __cpu_up returns.
287 set_cpu_online(cpu, true);
288 complete(&cpu_running);
291 * Setup the percpu timer for this CPU.
293 percpu_timer_setup();
299 * OK, it's off to the idle thread for us
304 void __init smp_cpus_done(unsigned int max_cpus)
307 unsigned long bogosum = 0;
309 for_each_online_cpu(cpu)
310 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
312 printk(KERN_INFO "SMP: Total of %d processors activated "
313 "(%lu.%02lu BogoMIPS).\n",
315 bogosum / (500000/HZ),
316 (bogosum / (5000/HZ)) % 100);
319 void __init smp_prepare_boot_cpu(void)
321 unsigned int cpu = smp_processor_id();
323 per_cpu(cpu_data, cpu).idle = current;
326 void __init smp_prepare_cpus(unsigned int max_cpus)
328 unsigned int ncores = num_possible_cpus();
332 smp_store_cpu_info(smp_processor_id());
335 * are we trying to boot more cores than exist?
337 if (max_cpus > ncores)
339 if (ncores > 1 && max_cpus) {
341 * Enable the local timer or broadcast device for the
342 * boot CPU, but only if we have more than one CPU.
344 percpu_timer_setup();
347 * Initialise the present map, which describes the set of CPUs
348 * actually populated at the present time. A platform should
349 * re-initialize the map in platform_smp_prepare_cpus() if
350 * present != possible (e.g. physical hotplug).
352 init_cpu_present(cpu_possible_mask);
355 * Initialise the SCU if there are more than one CPU
356 * and let them know where to start.
358 platform_smp_prepare_cpus(max_cpus);
362 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
364 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
369 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
371 smp_cross_call(mask, IPI_CALL_FUNC);
374 void arch_send_call_function_single_ipi(int cpu)
376 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
379 static const char *ipi_types[NR_IPI] = {
380 #define S(x,s) [x - IPI_TIMER] = s
381 S(IPI_TIMER, "Timer broadcast interrupts"),
382 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
383 S(IPI_CALL_FUNC, "Function call interrupts"),
384 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
385 S(IPI_CPU_STOP, "CPU stop interrupts"),
388 void show_ipi_list(struct seq_file *p, int prec)
392 for (i = 0; i < NR_IPI; i++) {
393 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
395 for_each_present_cpu(cpu)
396 seq_printf(p, "%10u ",
397 __get_irq_stat(cpu, ipi_irqs[i]));
399 seq_printf(p, " %s\n", ipi_types[i]);
403 u64 smp_irq_stat_cpu(unsigned int cpu)
408 for (i = 0; i < NR_IPI; i++)
409 sum += __get_irq_stat(cpu, ipi_irqs[i]);
415 * Timer (local or broadcast) support
417 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
419 static void ipi_timer(void)
421 struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
422 evt->event_handler(evt);
425 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
426 static void smp_timer_broadcast(const struct cpumask *mask)
428 smp_cross_call(mask, IPI_TIMER);
431 #define smp_timer_broadcast NULL
434 static void broadcast_timer_set_mode(enum clock_event_mode mode,
435 struct clock_event_device *evt)
439 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
441 evt->name = "dummy_timer";
442 evt->features = CLOCK_EVT_FEAT_ONESHOT |
443 CLOCK_EVT_FEAT_PERIODIC |
444 CLOCK_EVT_FEAT_DUMMY;
447 evt->set_mode = broadcast_timer_set_mode;
449 clockevents_register_device(evt);
452 static struct local_timer_ops *lt_ops;
454 #ifdef CONFIG_LOCAL_TIMERS
455 int local_timer_register(struct local_timer_ops *ops)
465 static void __cpuinit percpu_timer_setup(void)
467 unsigned int cpu = smp_processor_id();
468 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
470 evt->cpumask = cpumask_of(cpu);
471 evt->broadcast = smp_timer_broadcast;
473 if (!lt_ops || lt_ops->setup(evt))
474 broadcast_timer_setup(evt);
477 #ifdef CONFIG_HOTPLUG_CPU
479 * The generic clock events code purposely does not stop the local timer
480 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
483 static void percpu_timer_stop(void)
485 unsigned int cpu = smp_processor_id();
486 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
493 static DEFINE_RAW_SPINLOCK(stop_lock);
496 * ipi_cpu_stop - handle IPI from smp_send_stop()
498 static void ipi_cpu_stop(unsigned int cpu)
500 if (system_state == SYSTEM_BOOTING ||
501 system_state == SYSTEM_RUNNING) {
502 raw_spin_lock(&stop_lock);
503 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
505 raw_spin_unlock(&stop_lock);
508 set_cpu_online(cpu, false);
518 * Main handler for inter-processor interrupts
520 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
522 handle_IPI(ipinr, regs);
525 void handle_IPI(int ipinr, struct pt_regs *regs)
527 unsigned int cpu = smp_processor_id();
528 struct pt_regs *old_regs = set_irq_regs(regs);
530 if (ipinr >= IPI_TIMER && ipinr < IPI_TIMER + NR_IPI)
531 __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_TIMER]);
546 generic_smp_call_function_interrupt();
550 case IPI_CALL_FUNC_SINGLE:
552 generic_smp_call_function_single_interrupt();
563 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
567 set_irq_regs(old_regs);
570 void smp_send_reschedule(int cpu)
572 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
575 #ifdef CONFIG_HOTPLUG_CPU
576 static void smp_kill_cpus(cpumask_t *mask)
579 for_each_cpu(cpu, mask)
580 platform_cpu_kill(cpu);
583 static void smp_kill_cpus(cpumask_t *mask) { }
586 void smp_send_stop(void)
588 unsigned long timeout;
591 cpumask_copy(&mask, cpu_online_mask);
592 cpumask_clear_cpu(smp_processor_id(), &mask);
593 smp_cross_call(&mask, IPI_CPU_STOP);
595 /* Wait up to one second for other CPUs to stop */
596 timeout = USEC_PER_SEC;
597 while (num_online_cpus() > 1 && timeout--)
600 if (num_online_cpus() > 1)
601 pr_warning("SMP: failed to stop secondary CPUs\n");
603 smp_kill_cpus(&mask);
609 int setup_profiling_timer(unsigned int multiplier)