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 int __cpuinit __cpu_up(unsigned int cpu)
63 struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
64 struct task_struct *idle = ci->idle;
68 * Spawn a new process manually, if not already done.
69 * Grab a pointer to its task struct so we can mess with it
72 idle = fork_idle(cpu);
74 printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
80 * Since this idle thread is being re-used, call
81 * init_idle() to reinitialize the thread structure.
87 * We need to tell the secondary core where to find
88 * its stack and the page tables.
90 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
91 secondary_data.pgdir = virt_to_phys(idmap_pgd);
92 secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
93 __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
94 outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
97 * Now bring the CPU into our world.
99 ret = boot_secondary(cpu, idle);
101 unsigned long timeout;
104 * CPU was successfully started, wait for it
105 * to come online or time out.
107 timeout = jiffies + HZ;
108 while (time_before(jiffies, timeout)) {
116 if (!cpu_online(cpu)) {
117 pr_crit("CPU%u: failed to come online\n", cpu);
121 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
124 secondary_data.stack = NULL;
125 secondary_data.pgdir = 0;
130 #ifdef CONFIG_HOTPLUG_CPU
131 static void percpu_timer_stop(void);
134 * __cpu_disable runs on the processor to be shutdown.
136 int __cpu_disable(void)
138 unsigned int cpu = smp_processor_id();
139 struct task_struct *p;
142 ret = platform_cpu_disable(cpu);
147 * Take this CPU offline. Once we clear this, we can't return,
148 * and we must not schedule until we're ready to give up the cpu.
150 set_cpu_online(cpu, false);
153 * OK - migrate IRQs away from this CPU
158 * Stop the local timer for this CPU.
163 * Flush user cache and TLB mappings, and then remove this CPU
164 * from the vm mask set of all processes.
167 local_flush_tlb_all();
169 read_lock(&tasklist_lock);
170 for_each_process(p) {
172 cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
174 read_unlock(&tasklist_lock);
179 static DECLARE_COMPLETION(cpu_died);
182 * called on the thread which is asking for a CPU to be shutdown -
183 * waits until shutdown has completed, or it is timed out.
185 void __cpu_die(unsigned int cpu)
187 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
188 pr_err("CPU%u: cpu didn't die\n", cpu);
191 printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
193 if (!platform_cpu_kill(cpu))
194 printk("CPU%u: unable to kill\n", cpu);
198 * Called from the idle thread for the CPU which has been shutdown.
200 * Note that we disable IRQs here, but do not re-enable them
201 * before returning to the caller. This is also the behaviour
202 * of the other hotplug-cpu capable cores, so presumably coming
203 * out of idle fixes this.
205 void __ref cpu_die(void)
207 unsigned int cpu = smp_processor_id();
214 /* Tell __cpu_die() that this CPU is now safe to dispose of */
218 * actual CPU shutdown procedure is at least platform (if not
221 platform_cpu_die(cpu);
224 * Do not return to the idle loop - jump back to the secondary
225 * cpu initialisation. There's some initialisation which needs
226 * to be repeated to undo the effects of taking the CPU offline.
228 __asm__("mov sp, %0\n"
230 " b secondary_start_kernel"
232 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
234 #endif /* CONFIG_HOTPLUG_CPU */
236 int __cpu_logical_map[NR_CPUS];
238 void __init smp_setup_processor_id(void)
241 u32 cpu = is_smp() ? read_cpuid_mpidr() & 0xff : 0;
243 cpu_logical_map(0) = cpu;
244 for (i = 1; i < NR_CPUS; ++i)
245 cpu_logical_map(i) = i == cpu ? 0 : i;
247 printk(KERN_INFO "Booting Linux on physical CPU %d\n", cpu);
251 * Called by both boot and secondaries to move global data into
252 * per-processor storage.
254 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
256 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
258 cpu_info->loops_per_jiffy = loops_per_jiffy;
260 store_cpu_topology(cpuid);
264 * This is the secondary CPU boot entry. We're using this CPUs
265 * idle thread stack, but a set of temporary page tables.
267 asmlinkage void __cpuinit secondary_start_kernel(void)
269 struct mm_struct *mm = &init_mm;
270 unsigned int cpu = smp_processor_id();
272 printk("CPU%u: Booted secondary processor\n", cpu);
275 * All kernel threads share the same mm context; grab a
276 * reference and switch to it.
278 atomic_inc(&mm->mm_count);
279 current->active_mm = mm;
280 cpumask_set_cpu(cpu, mm_cpumask(mm));
281 cpu_switch_mm(mm->pgd, mm);
282 enter_lazy_tlb(mm, current);
283 local_flush_tlb_all();
287 trace_hardirqs_off();
290 * Give the platform a chance to do its own initialisation.
292 platform_secondary_init(cpu);
294 notify_cpu_starting(cpu);
298 smp_store_cpu_info(cpu);
301 * OK, now it's safe to let the boot CPU continue. Wait for
302 * the CPU migration code to notice that the CPU is online
303 * before we continue.
305 set_cpu_online(cpu, true);
308 * Setup the percpu timer for this CPU.
310 percpu_timer_setup();
312 while (!cpu_active(cpu))
316 * cpu_active bit is set, so it's safe to enalbe interrupts
323 * OK, it's off to the idle thread for us
328 void __init smp_cpus_done(unsigned int max_cpus)
331 unsigned long bogosum = 0;
333 for_each_online_cpu(cpu)
334 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
336 printk(KERN_INFO "SMP: Total of %d processors activated "
337 "(%lu.%02lu BogoMIPS).\n",
339 bogosum / (500000/HZ),
340 (bogosum / (5000/HZ)) % 100);
343 void __init smp_prepare_boot_cpu(void)
345 unsigned int cpu = smp_processor_id();
347 per_cpu(cpu_data, cpu).idle = current;
350 void __init smp_prepare_cpus(unsigned int max_cpus)
352 unsigned int ncores = num_possible_cpus();
356 smp_store_cpu_info(smp_processor_id());
359 * are we trying to boot more cores than exist?
361 if (max_cpus > ncores)
363 if (ncores > 1 && max_cpus) {
365 * Enable the local timer or broadcast device for the
366 * boot CPU, but only if we have more than one CPU.
368 percpu_timer_setup();
371 * Initialise the present map, which describes the set of CPUs
372 * actually populated at the present time. A platform should
373 * re-initialize the map in platform_smp_prepare_cpus() if
374 * present != possible (e.g. physical hotplug).
376 init_cpu_present(&cpu_possible_map);
379 * Initialise the SCU if there are more than one CPU
380 * and let them know where to start.
382 platform_smp_prepare_cpus(max_cpus);
386 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
388 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
393 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
395 smp_cross_call(mask, IPI_CALL_FUNC);
398 void arch_send_call_function_single_ipi(int cpu)
400 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
403 static const char *ipi_types[NR_IPI] = {
404 #define S(x,s) [x - IPI_TIMER] = s
405 S(IPI_TIMER, "Timer broadcast interrupts"),
406 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
407 S(IPI_CALL_FUNC, "Function call interrupts"),
408 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
409 S(IPI_CPU_STOP, "CPU stop interrupts"),
412 void show_ipi_list(struct seq_file *p, int prec)
416 for (i = 0; i < NR_IPI; i++) {
417 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
419 for_each_present_cpu(cpu)
420 seq_printf(p, "%10u ",
421 __get_irq_stat(cpu, ipi_irqs[i]));
423 seq_printf(p, " %s\n", ipi_types[i]);
427 u64 smp_irq_stat_cpu(unsigned int cpu)
432 for (i = 0; i < NR_IPI; i++)
433 sum += __get_irq_stat(cpu, ipi_irqs[i]);
439 * Timer (local or broadcast) support
441 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
443 static void ipi_timer(void)
445 struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
447 evt->event_handler(evt);
451 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
452 static void smp_timer_broadcast(const struct cpumask *mask)
454 smp_cross_call(mask, IPI_TIMER);
457 #define smp_timer_broadcast NULL
460 static void broadcast_timer_set_mode(enum clock_event_mode mode,
461 struct clock_event_device *evt)
465 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
467 evt->name = "dummy_timer";
468 evt->features = CLOCK_EVT_FEAT_ONESHOT |
469 CLOCK_EVT_FEAT_PERIODIC |
470 CLOCK_EVT_FEAT_DUMMY;
473 evt->set_mode = broadcast_timer_set_mode;
475 clockevents_register_device(evt);
478 void __cpuinit percpu_timer_setup(void)
480 unsigned int cpu = smp_processor_id();
481 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
483 evt->cpumask = cpumask_of(cpu);
484 evt->broadcast = smp_timer_broadcast;
486 if (local_timer_setup(evt))
487 broadcast_timer_setup(evt);
490 #ifdef CONFIG_HOTPLUG_CPU
492 * The generic clock events code purposely does not stop the local timer
493 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
496 static void percpu_timer_stop(void)
498 unsigned int cpu = smp_processor_id();
499 struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
501 local_timer_stop(evt);
505 static DEFINE_RAW_SPINLOCK(stop_lock);
508 * ipi_cpu_stop - handle IPI from smp_send_stop()
510 static void ipi_cpu_stop(unsigned int cpu)
512 if (system_state == SYSTEM_BOOTING ||
513 system_state == SYSTEM_RUNNING) {
514 raw_spin_lock(&stop_lock);
515 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
517 raw_spin_unlock(&stop_lock);
520 set_cpu_online(cpu, false);
525 #ifdef CONFIG_HOTPLUG_CPU
526 platform_cpu_kill(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);
546 if (ipinr >= IPI_TIMER && ipinr < IPI_TIMER + NR_IPI)
547 __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_TIMER]);
559 generic_smp_call_function_interrupt();
562 case IPI_CALL_FUNC_SINGLE:
563 generic_smp_call_function_single_interrupt();
571 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
575 set_irq_regs(old_regs);
578 void smp_send_reschedule(int cpu)
580 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
583 void smp_send_stop(void)
585 unsigned long timeout;
587 if (num_online_cpus() > 1) {
588 cpumask_t mask = cpu_online_map;
589 cpu_clear(smp_processor_id(), mask);
591 smp_cross_call(&mask, IPI_CPU_STOP);
594 /* Wait up to one second for other CPUs to stop */
595 timeout = USEC_PER_SEC;
596 while (num_online_cpus() > 1 && timeout--)
599 if (num_online_cpus() > 1)
600 pr_warning("SMP: failed to stop secondary CPUs\n");
606 int setup_profiling_timer(unsigned int multiplier)