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/localtimer.h>
45 #include <asm/smp_plat.h>
46 #include <asm/mach/arch.h>
49 * as from 2.5, kernels no longer have an init_tasks structure
50 * so we need some other way of telling a new secondary core
51 * where to place its SVC stack
53 struct secondary_data secondary_data
;
56 * control for which core is the next to come out of the secondary
59 volatile int __cpuinitdata pen_release
= -1;
70 static DECLARE_COMPLETION(cpu_running
);
72 static struct smp_operations smp_ops
;
74 void __init
smp_set_ops(struct smp_operations
*ops
)
80 int __cpuinit
__cpu_up(unsigned int cpu
, struct task_struct
*idle
)
85 * We need to tell the secondary core where to find
86 * its stack and the page tables.
88 secondary_data
.stack
= task_stack_page(idle
) + THREAD_START_SP
;
89 secondary_data
.pgdir
= virt_to_phys(idmap_pgd
);
90 secondary_data
.swapper_pg_dir
= virt_to_phys(swapper_pg_dir
);
91 __cpuc_flush_dcache_area(&secondary_data
, sizeof(secondary_data
));
92 outer_clean_range(__pa(&secondary_data
), __pa(&secondary_data
+ 1));
95 * Now bring the CPU into our world.
97 ret
= boot_secondary(cpu
, idle
);
100 * CPU was successfully started, wait for it
101 * to come online or time out.
103 wait_for_completion_timeout(&cpu_running
,
104 msecs_to_jiffies(1000));
106 if (!cpu_online(cpu
)) {
107 pr_crit("CPU%u: failed to come online\n", cpu
);
111 pr_err("CPU%u: failed to boot: %d\n", cpu
, ret
);
114 secondary_data
.stack
= NULL
;
115 secondary_data
.pgdir
= 0;
120 /* platform specific SMP operations */
121 void __init
smp_init_cpus(void)
123 if (smp_ops
.smp_init_cpus
)
124 smp_ops
.smp_init_cpus();
127 static void __init
platform_smp_prepare_cpus(unsigned int max_cpus
)
129 if (smp_ops
.smp_prepare_cpus
)
130 smp_ops
.smp_prepare_cpus(max_cpus
);
133 static void __cpuinit
platform_secondary_init(unsigned int cpu
)
135 if (smp_ops
.smp_secondary_init
)
136 smp_ops
.smp_secondary_init(cpu
);
139 int __cpuinit
boot_secondary(unsigned int cpu
, struct task_struct
*idle
)
141 if (smp_ops
.smp_boot_secondary
)
142 return smp_ops
.smp_boot_secondary(cpu
, idle
);
146 #ifdef CONFIG_HOTPLUG_CPU
147 static void percpu_timer_stop(void);
149 static int platform_cpu_kill(unsigned int cpu
)
151 if (smp_ops
.cpu_kill
)
152 return smp_ops
.cpu_kill(cpu
);
156 static void platform_cpu_die(unsigned int cpu
)
159 smp_ops
.cpu_die(cpu
);
162 static int platform_cpu_disable(unsigned int cpu
)
164 if (smp_ops
.cpu_disable
)
165 return smp_ops
.cpu_disable(cpu
);
168 * By default, allow disabling all CPUs except the first one,
169 * since this is special on a lot of platforms, e.g. because
170 * of clock tick interrupts.
172 return cpu
== 0 ? -EPERM
: 0;
175 * __cpu_disable runs on the processor to be shutdown.
177 int __cpuinit
__cpu_disable(void)
179 unsigned int cpu
= smp_processor_id();
182 ret
= platform_cpu_disable(cpu
);
187 * Take this CPU offline. Once we clear this, we can't return,
188 * and we must not schedule until we're ready to give up the cpu.
190 set_cpu_online(cpu
, false);
193 * OK - migrate IRQs away from this CPU
198 * Stop the local timer for this CPU.
203 * Flush user cache and TLB mappings, and then remove this CPU
204 * from the vm mask set of all processes.
207 local_flush_tlb_all();
209 clear_tasks_mm_cpumask(cpu
);
214 static DECLARE_COMPLETION(cpu_died
);
217 * called on the thread which is asking for a CPU to be shutdown -
218 * waits until shutdown has completed, or it is timed out.
220 void __cpuinit
__cpu_die(unsigned int cpu
)
222 if (!wait_for_completion_timeout(&cpu_died
, msecs_to_jiffies(5000))) {
223 pr_err("CPU%u: cpu didn't die\n", cpu
);
226 printk(KERN_NOTICE
"CPU%u: shutdown\n", cpu
);
228 if (!platform_cpu_kill(cpu
))
229 printk("CPU%u: unable to kill\n", cpu
);
233 * Called from the idle thread for the CPU which has been shutdown.
235 * Note that we disable IRQs here, but do not re-enable them
236 * before returning to the caller. This is also the behaviour
237 * of the other hotplug-cpu capable cores, so presumably coming
238 * out of idle fixes this.
240 void __ref
cpu_die(void)
242 unsigned int cpu
= smp_processor_id();
249 /* Tell __cpu_die() that this CPU is now safe to dispose of */
250 RCU_NONIDLE(complete(&cpu_died
));
253 * actual CPU shutdown procedure is at least platform (if not
256 platform_cpu_die(cpu
);
259 * Do not return to the idle loop - jump back to the secondary
260 * cpu initialisation. There's some initialisation which needs
261 * to be repeated to undo the effects of taking the CPU offline.
263 __asm__("mov sp, %0\n"
265 " b secondary_start_kernel"
267 : "r" (task_stack_page(current
) + THREAD_SIZE
- 8));
269 #endif /* CONFIG_HOTPLUG_CPU */
272 * Called by both boot and secondaries to move global data into
273 * per-processor storage.
275 static void __cpuinit
smp_store_cpu_info(unsigned int cpuid
)
277 struct cpuinfo_arm
*cpu_info
= &per_cpu(cpu_data
, cpuid
);
279 cpu_info
->loops_per_jiffy
= loops_per_jiffy
;
281 store_cpu_topology(cpuid
);
284 static void percpu_timer_setup(void);
287 * This is the secondary CPU boot entry. We're using this CPUs
288 * idle thread stack, but a set of temporary page tables.
290 asmlinkage
void __cpuinit
secondary_start_kernel(void)
292 struct mm_struct
*mm
= &init_mm
;
293 unsigned int cpu
= smp_processor_id();
296 * All kernel threads share the same mm context; grab a
297 * reference and switch to it.
299 atomic_inc(&mm
->mm_count
);
300 current
->active_mm
= mm
;
301 cpumask_set_cpu(cpu
, mm_cpumask(mm
));
302 cpu_switch_mm(mm
->pgd
, mm
);
303 enter_lazy_tlb(mm
, current
);
304 local_flush_tlb_all();
306 printk("CPU%u: Booted secondary processor\n", cpu
);
310 trace_hardirqs_off();
313 * Give the platform a chance to do its own initialisation.
315 platform_secondary_init(cpu
);
317 notify_cpu_starting(cpu
);
321 smp_store_cpu_info(cpu
);
324 * OK, now it's safe to let the boot CPU continue. Wait for
325 * the CPU migration code to notice that the CPU is online
326 * before we continue - which happens after __cpu_up returns.
328 set_cpu_online(cpu
, true);
329 complete(&cpu_running
);
332 * Setup the percpu timer for this CPU.
334 percpu_timer_setup();
340 * OK, it's off to the idle thread for us
345 void __init
smp_cpus_done(unsigned int max_cpus
)
348 unsigned long bogosum
= 0;
350 for_each_online_cpu(cpu
)
351 bogosum
+= per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
353 printk(KERN_INFO
"SMP: Total of %d processors activated "
354 "(%lu.%02lu BogoMIPS).\n",
356 bogosum
/ (500000/HZ
),
357 (bogosum
/ (5000/HZ
)) % 100);
360 void __init
smp_prepare_boot_cpu(void)
364 void __init
smp_prepare_cpus(unsigned int max_cpus
)
366 unsigned int ncores
= num_possible_cpus();
370 smp_store_cpu_info(smp_processor_id());
373 * are we trying to boot more cores than exist?
375 if (max_cpus
> ncores
)
377 if (ncores
> 1 && max_cpus
) {
379 * Enable the local timer or broadcast device for the
380 * boot CPU, but only if we have more than one CPU.
382 percpu_timer_setup();
385 * Initialise the present map, which describes the set of CPUs
386 * actually populated at the present time. A platform should
387 * re-initialize the map in platform_smp_prepare_cpus() if
388 * present != possible (e.g. physical hotplug).
390 init_cpu_present(cpu_possible_mask
);
393 * Initialise the SCU if there are more than one CPU
394 * and let them know where to start.
396 platform_smp_prepare_cpus(max_cpus
);
400 static void (*smp_cross_call
)(const struct cpumask
*, unsigned int);
402 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
407 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
409 smp_cross_call(mask
, IPI_CALL_FUNC
);
412 void arch_send_call_function_single_ipi(int cpu
)
414 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC_SINGLE
);
417 static const char *ipi_types
[NR_IPI
] = {
418 #define S(x,s) [x] = s
419 S(IPI_WAKEUP
, "CPU wakeup interrupts"),
420 S(IPI_TIMER
, "Timer broadcast interrupts"),
421 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
422 S(IPI_CALL_FUNC
, "Function call interrupts"),
423 S(IPI_CALL_FUNC_SINGLE
, "Single function call interrupts"),
424 S(IPI_CPU_STOP
, "CPU stop interrupts"),
427 void show_ipi_list(struct seq_file
*p
, int prec
)
431 for (i
= 0; i
< NR_IPI
; i
++) {
432 seq_printf(p
, "%*s%u: ", prec
- 1, "IPI", i
);
434 for_each_present_cpu(cpu
)
435 seq_printf(p
, "%10u ",
436 __get_irq_stat(cpu
, ipi_irqs
[i
]));
438 seq_printf(p
, " %s\n", ipi_types
[i
]);
442 u64
smp_irq_stat_cpu(unsigned int cpu
)
447 for (i
= 0; i
< NR_IPI
; i
++)
448 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
454 * Timer (local or broadcast) support
456 static DEFINE_PER_CPU(struct clock_event_device
, percpu_clockevent
);
458 static void ipi_timer(void)
460 struct clock_event_device
*evt
= &__get_cpu_var(percpu_clockevent
);
461 evt
->event_handler(evt
);
464 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
465 static void smp_timer_broadcast(const struct cpumask
*mask
)
467 smp_cross_call(mask
, IPI_TIMER
);
470 #define smp_timer_broadcast NULL
473 static void broadcast_timer_set_mode(enum clock_event_mode mode
,
474 struct clock_event_device
*evt
)
478 static void __cpuinit
broadcast_timer_setup(struct clock_event_device
*evt
)
480 evt
->name
= "dummy_timer";
481 evt
->features
= CLOCK_EVT_FEAT_ONESHOT
|
482 CLOCK_EVT_FEAT_PERIODIC
|
483 CLOCK_EVT_FEAT_DUMMY
;
486 evt
->set_mode
= broadcast_timer_set_mode
;
488 clockevents_register_device(evt
);
491 static struct local_timer_ops
*lt_ops
;
493 #ifdef CONFIG_LOCAL_TIMERS
494 int local_timer_register(struct local_timer_ops
*ops
)
496 if (!is_smp() || !setup_max_cpus
)
507 static void __cpuinit
percpu_timer_setup(void)
509 unsigned int cpu
= smp_processor_id();
510 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
512 evt
->cpumask
= cpumask_of(cpu
);
513 evt
->broadcast
= smp_timer_broadcast
;
515 if (!lt_ops
|| lt_ops
->setup(evt
))
516 broadcast_timer_setup(evt
);
519 #ifdef CONFIG_HOTPLUG_CPU
521 * The generic clock events code purposely does not stop the local timer
522 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
525 static void percpu_timer_stop(void)
527 unsigned int cpu
= smp_processor_id();
528 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
535 static DEFINE_RAW_SPINLOCK(stop_lock
);
538 * ipi_cpu_stop - handle IPI from smp_send_stop()
540 static void ipi_cpu_stop(unsigned int cpu
)
542 if (system_state
== SYSTEM_BOOTING
||
543 system_state
== SYSTEM_RUNNING
) {
544 raw_spin_lock(&stop_lock
);
545 printk(KERN_CRIT
"CPU%u: stopping\n", cpu
);
547 raw_spin_unlock(&stop_lock
);
550 set_cpu_online(cpu
, false);
560 * Main handler for inter-processor interrupts
562 asmlinkage
void __exception_irq_entry
do_IPI(int ipinr
, struct pt_regs
*regs
)
564 handle_IPI(ipinr
, regs
);
567 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
569 unsigned int cpu
= smp_processor_id();
570 struct pt_regs
*old_regs
= set_irq_regs(regs
);
573 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
591 generic_smp_call_function_interrupt();
595 case IPI_CALL_FUNC_SINGLE
:
597 generic_smp_call_function_single_interrupt();
608 printk(KERN_CRIT
"CPU%u: Unknown IPI message 0x%x\n",
612 set_irq_regs(old_regs
);
615 void smp_send_reschedule(int cpu
)
617 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
620 #ifdef CONFIG_HOTPLUG_CPU
621 static void smp_kill_cpus(cpumask_t
*mask
)
624 for_each_cpu(cpu
, mask
)
625 platform_cpu_kill(cpu
);
628 static void smp_kill_cpus(cpumask_t
*mask
) { }
631 void smp_send_stop(void)
633 unsigned long timeout
;
636 cpumask_copy(&mask
, cpu_online_mask
);
637 cpumask_clear_cpu(smp_processor_id(), &mask
);
638 if (!cpumask_empty(&mask
))
639 smp_cross_call(&mask
, IPI_CPU_STOP
);
641 /* Wait up to one second for other CPUs to stop */
642 timeout
= USEC_PER_SEC
;
643 while (num_online_cpus() > 1 && timeout
--)
646 if (num_online_cpus() > 1)
647 pr_warning("SMP: failed to stop secondary CPUs\n");
649 smp_kill_cpus(&mask
);
655 int setup_profiling_timer(unsigned int multiplier
)
660 #ifdef CONFIG_CPU_FREQ
662 static DEFINE_PER_CPU(unsigned long, l_p_j_ref
);
663 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq
);
664 static unsigned long global_l_p_j_ref
;
665 static unsigned long global_l_p_j_ref_freq
;
667 static int cpufreq_callback(struct notifier_block
*nb
,
668 unsigned long val
, void *data
)
670 struct cpufreq_freqs
*freq
= data
;
673 if (freq
->flags
& CPUFREQ_CONST_LOOPS
)
676 if (!per_cpu(l_p_j_ref
, cpu
)) {
677 per_cpu(l_p_j_ref
, cpu
) =
678 per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
679 per_cpu(l_p_j_ref_freq
, cpu
) = freq
->old
;
680 if (!global_l_p_j_ref
) {
681 global_l_p_j_ref
= loops_per_jiffy
;
682 global_l_p_j_ref_freq
= freq
->old
;
686 if ((val
== CPUFREQ_PRECHANGE
&& freq
->old
< freq
->new) ||
687 (val
== CPUFREQ_POSTCHANGE
&& freq
->old
> freq
->new) ||
688 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
689 loops_per_jiffy
= cpufreq_scale(global_l_p_j_ref
,
690 global_l_p_j_ref_freq
,
692 per_cpu(cpu_data
, cpu
).loops_per_jiffy
=
693 cpufreq_scale(per_cpu(l_p_j_ref
, cpu
),
694 per_cpu(l_p_j_ref_freq
, cpu
),
700 static struct notifier_block cpufreq_notifier
= {
701 .notifier_call
= cpufreq_callback
,
704 static int __init
register_cpufreq_notifier(void)
706 return cpufreq_register_notifier(&cpufreq_notifier
,
707 CPUFREQ_TRANSITION_NOTIFIER
);
709 core_initcall(register_cpufreq_notifier
);