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>
47 #include <asm/mach/arch.h>
51 * as from 2.5, kernels no longer have an init_tasks structure
52 * so we need some other way of telling a new secondary core
53 * where to place its SVC stack
55 struct secondary_data secondary_data
;
58 * control for which core is the next to come out of the secondary
61 volatile int pen_release
= -1;
72 static DECLARE_COMPLETION(cpu_running
);
74 static struct smp_operations smp_ops
;
76 void __init
smp_set_ops(struct smp_operations
*ops
)
82 static unsigned long get_arch_pgd(pgd_t
*pgd
)
84 phys_addr_t pgdir
= virt_to_phys(pgd
);
85 BUG_ON(pgdir
& ARCH_PGD_MASK
);
86 return pgdir
>> ARCH_PGD_SHIFT
;
89 int __cpu_up(unsigned int cpu
, struct task_struct
*idle
)
94 * We need to tell the secondary core where to find
95 * its stack and the page tables.
97 secondary_data
.stack
= task_stack_page(idle
) + THREAD_START_SP
;
99 secondary_data
.mpu_rgn_szr
= mpu_rgn_info
.rgns
[MPU_RAM_REGION
].drsr
;
103 secondary_data
.pgdir
= get_arch_pgd(idmap_pgd
);
104 secondary_data
.swapper_pg_dir
= get_arch_pgd(swapper_pg_dir
);
106 __cpuc_flush_dcache_area(&secondary_data
, sizeof(secondary_data
));
107 outer_clean_range(__pa(&secondary_data
), __pa(&secondary_data
+ 1));
110 * Now bring the CPU into our world.
112 ret
= boot_secondary(cpu
, idle
);
115 * CPU was successfully started, wait for it
116 * to come online or time out.
118 wait_for_completion_timeout(&cpu_running
,
119 msecs_to_jiffies(1000));
121 if (!cpu_online(cpu
)) {
122 pr_crit("CPU%u: failed to come online\n", cpu
);
126 pr_err("CPU%u: failed to boot: %d\n", cpu
, ret
);
130 memset(&secondary_data
, 0, sizeof(secondary_data
));
134 /* platform specific SMP operations */
135 void __init
smp_init_cpus(void)
137 if (smp_ops
.smp_init_cpus
)
138 smp_ops
.smp_init_cpus();
141 int boot_secondary(unsigned int cpu
, struct task_struct
*idle
)
143 if (smp_ops
.smp_boot_secondary
)
144 return smp_ops
.smp_boot_secondary(cpu
, idle
);
148 int platform_can_cpu_hotplug(void)
150 #ifdef CONFIG_HOTPLUG_CPU
151 if (smp_ops
.cpu_kill
)
158 #ifdef CONFIG_HOTPLUG_CPU
159 static void percpu_timer_stop(void);
161 static int platform_cpu_kill(unsigned int cpu
)
163 if (smp_ops
.cpu_kill
)
164 return smp_ops
.cpu_kill(cpu
);
168 static int platform_cpu_disable(unsigned int cpu
)
170 if (smp_ops
.cpu_disable
)
171 return smp_ops
.cpu_disable(cpu
);
174 * By default, allow disabling all CPUs except the first one,
175 * since this is special on a lot of platforms, e.g. because
176 * of clock tick interrupts.
178 return cpu
== 0 ? -EPERM
: 0;
181 * __cpu_disable runs on the processor to be shutdown.
183 int __cpu_disable(void)
185 unsigned int cpu
= smp_processor_id();
188 ret
= platform_cpu_disable(cpu
);
193 * Take this CPU offline. Once we clear this, we can't return,
194 * and we must not schedule until we're ready to give up the cpu.
196 set_cpu_online(cpu
, false);
199 * OK - migrate IRQs away from this CPU
204 * Stop the local timer for this CPU.
209 * Flush user cache and TLB mappings, and then remove this CPU
210 * from the vm mask set of all processes.
212 * Caches are flushed to the Level of Unification Inner Shareable
213 * to write-back dirty lines to unified caches shared by all CPUs.
216 local_flush_tlb_all();
218 clear_tasks_mm_cpumask(cpu
);
223 static DECLARE_COMPLETION(cpu_died
);
226 * called on the thread which is asking for a CPU to be shutdown -
227 * waits until shutdown has completed, or it is timed out.
229 void __cpu_die(unsigned int cpu
)
231 if (!wait_for_completion_timeout(&cpu_died
, msecs_to_jiffies(5000))) {
232 pr_err("CPU%u: cpu didn't die\n", cpu
);
235 printk(KERN_NOTICE
"CPU%u: shutdown\n", cpu
);
238 * platform_cpu_kill() is generally expected to do the powering off
239 * and/or cutting of clocks to the dying CPU. Optionally, this may
240 * be done by the CPU which is dying in preference to supporting
241 * this call, but that means there is _no_ synchronisation between
242 * the requesting CPU and the dying CPU actually losing power.
244 if (!platform_cpu_kill(cpu
))
245 printk("CPU%u: unable to kill\n", cpu
);
249 * Called from the idle thread for the CPU which has been shutdown.
251 * Note that we disable IRQs here, but do not re-enable them
252 * before returning to the caller. This is also the behaviour
253 * of the other hotplug-cpu capable cores, so presumably coming
254 * out of idle fixes this.
256 void __ref
cpu_die(void)
258 unsigned int cpu
= smp_processor_id();
265 * Flush the data out of the L1 cache for this CPU. This must be
266 * before the completion to ensure that data is safely written out
267 * before platform_cpu_kill() gets called - which may disable
268 * *this* CPU and power down its cache.
273 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
274 * this returns, power and/or clocks can be removed at any point
275 * from this CPU and its cache by platform_cpu_kill().
280 * Ensure that the cache lines associated with that completion are
281 * written out. This covers the case where _this_ CPU is doing the
282 * powering down, to ensure that the completion is visible to the
283 * CPU waiting for this one.
288 * The actual CPU shutdown procedure is at least platform (if not
289 * CPU) specific. This may remove power, or it may simply spin.
291 * Platforms are generally expected *NOT* to return from this call,
292 * although there are some which do because they have no way to
293 * power down the CPU. These platforms are the _only_ reason we
294 * have a return path which uses the fragment of assembly below.
296 * The return path should not be used for platforms which can
300 smp_ops
.cpu_die(cpu
);
303 * Do not return to the idle loop - jump back to the secondary
304 * cpu initialisation. There's some initialisation which needs
305 * to be repeated to undo the effects of taking the CPU offline.
307 __asm__("mov sp, %0\n"
309 " b secondary_start_kernel"
311 : "r" (task_stack_page(current
) + THREAD_SIZE
- 8));
313 #endif /* CONFIG_HOTPLUG_CPU */
316 * Called by both boot and secondaries to move global data into
317 * per-processor storage.
319 static void smp_store_cpu_info(unsigned int cpuid
)
321 struct cpuinfo_arm
*cpu_info
= &per_cpu(cpu_data
, cpuid
);
323 cpu_info
->loops_per_jiffy
= loops_per_jiffy
;
324 cpu_info
->cpuid
= read_cpuid_id();
326 store_cpu_topology(cpuid
);
329 static void percpu_timer_setup(void);
332 * This is the secondary CPU boot entry. We're using this CPUs
333 * idle thread stack, but a set of temporary page tables.
335 asmlinkage
void secondary_start_kernel(void)
337 struct mm_struct
*mm
= &init_mm
;
341 * The identity mapping is uncached (strongly ordered), so
342 * switch away from it before attempting any exclusive accesses.
344 cpu_switch_mm(mm
->pgd
, mm
);
345 local_flush_bp_all();
346 enter_lazy_tlb(mm
, current
);
347 local_flush_tlb_all();
350 * All kernel threads share the same mm context; grab a
351 * reference and switch to it.
353 cpu
= smp_processor_id();
354 atomic_inc(&mm
->mm_count
);
355 current
->active_mm
= mm
;
356 cpumask_set_cpu(cpu
, mm_cpumask(mm
));
360 printk("CPU%u: Booted secondary processor\n", cpu
);
363 trace_hardirqs_off();
366 * Give the platform a chance to do its own initialisation.
368 if (smp_ops
.smp_secondary_init
)
369 smp_ops
.smp_secondary_init(cpu
);
371 notify_cpu_starting(cpu
);
375 smp_store_cpu_info(cpu
);
378 * OK, now it's safe to let the boot CPU continue. Wait for
379 * the CPU migration code to notice that the CPU is online
380 * before we continue - which happens after __cpu_up returns.
382 set_cpu_online(cpu
, true);
383 complete(&cpu_running
);
386 * Setup the percpu timer for this CPU.
388 percpu_timer_setup();
394 * OK, it's off to the idle thread for us
396 cpu_startup_entry(CPUHP_ONLINE
);
399 void __init
smp_cpus_done(unsigned int max_cpus
)
402 unsigned long bogosum
= 0;
404 for_each_online_cpu(cpu
)
405 bogosum
+= per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
407 printk(KERN_INFO
"SMP: Total of %d processors activated "
408 "(%lu.%02lu BogoMIPS).\n",
410 bogosum
/ (500000/HZ
),
411 (bogosum
/ (5000/HZ
)) % 100);
416 void __init
smp_prepare_boot_cpu(void)
418 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
421 void __init
smp_prepare_cpus(unsigned int max_cpus
)
423 unsigned int ncores
= num_possible_cpus();
427 smp_store_cpu_info(smp_processor_id());
430 * are we trying to boot more cores than exist?
432 if (max_cpus
> ncores
)
434 if (ncores
> 1 && max_cpus
) {
436 * Enable the local timer or broadcast device for the
437 * boot CPU, but only if we have more than one CPU.
439 percpu_timer_setup();
442 * Initialise the present map, which describes the set of CPUs
443 * actually populated at the present time. A platform should
444 * re-initialize the map in the platforms smp_prepare_cpus()
445 * if present != possible (e.g. physical hotplug).
447 init_cpu_present(cpu_possible_mask
);
450 * Initialise the SCU if there are more than one CPU
451 * and let them know where to start.
453 if (smp_ops
.smp_prepare_cpus
)
454 smp_ops
.smp_prepare_cpus(max_cpus
);
458 static void (*smp_cross_call
)(const struct cpumask
*, unsigned int);
460 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
466 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
468 smp_cross_call(mask
, IPI_CALL_FUNC
);
471 void arch_send_wakeup_ipi_mask(const struct cpumask
*mask
)
473 smp_cross_call(mask
, IPI_WAKEUP
);
476 void arch_send_call_function_single_ipi(int cpu
)
478 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC_SINGLE
);
481 static const char *ipi_types
[NR_IPI
] = {
482 #define S(x,s) [x] = s
483 S(IPI_WAKEUP
, "CPU wakeup interrupts"),
484 S(IPI_TIMER
, "Timer broadcast interrupts"),
485 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
486 S(IPI_CALL_FUNC
, "Function call interrupts"),
487 S(IPI_CALL_FUNC_SINGLE
, "Single function call interrupts"),
488 S(IPI_CPU_STOP
, "CPU stop interrupts"),
491 void show_ipi_list(struct seq_file
*p
, int prec
)
495 for (i
= 0; i
< NR_IPI
; i
++) {
496 seq_printf(p
, "%*s%u: ", prec
- 1, "IPI", i
);
498 for_each_online_cpu(cpu
)
499 seq_printf(p
, "%10u ",
500 __get_irq_stat(cpu
, ipi_irqs
[i
]));
502 seq_printf(p
, " %s\n", ipi_types
[i
]);
506 u64
smp_irq_stat_cpu(unsigned int cpu
)
511 for (i
= 0; i
< NR_IPI
; i
++)
512 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
518 * Timer (local or broadcast) support
520 static DEFINE_PER_CPU(struct clock_event_device
, percpu_clockevent
);
522 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
523 void tick_broadcast(const struct cpumask
*mask
)
525 smp_cross_call(mask
, IPI_TIMER
);
529 static void broadcast_timer_set_mode(enum clock_event_mode mode
,
530 struct clock_event_device
*evt
)
534 static void broadcast_timer_setup(struct clock_event_device
*evt
)
536 evt
->name
= "dummy_timer";
537 evt
->features
= CLOCK_EVT_FEAT_ONESHOT
|
538 CLOCK_EVT_FEAT_PERIODIC
|
539 CLOCK_EVT_FEAT_DUMMY
;
542 evt
->set_mode
= broadcast_timer_set_mode
;
544 clockevents_register_device(evt
);
547 static struct local_timer_ops
*lt_ops
;
549 #ifdef CONFIG_LOCAL_TIMERS
550 int local_timer_register(struct local_timer_ops
*ops
)
552 if (!is_smp() || !setup_max_cpus
)
563 static void percpu_timer_setup(void)
565 unsigned int cpu
= smp_processor_id();
566 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
568 evt
->cpumask
= cpumask_of(cpu
);
570 if (!lt_ops
|| lt_ops
->setup(evt
))
571 broadcast_timer_setup(evt
);
574 #ifdef CONFIG_HOTPLUG_CPU
576 * The generic clock events code purposely does not stop the local timer
577 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
580 static void percpu_timer_stop(void)
582 unsigned int cpu
= smp_processor_id();
583 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
590 static DEFINE_RAW_SPINLOCK(stop_lock
);
593 * ipi_cpu_stop - handle IPI from smp_send_stop()
595 static void ipi_cpu_stop(unsigned int cpu
)
597 if (system_state
== SYSTEM_BOOTING
||
598 system_state
== SYSTEM_RUNNING
) {
599 raw_spin_lock(&stop_lock
);
600 printk(KERN_CRIT
"CPU%u: stopping\n", cpu
);
602 raw_spin_unlock(&stop_lock
);
605 set_cpu_online(cpu
, false);
615 * Main handler for inter-processor interrupts
617 asmlinkage
void __exception_irq_entry
do_IPI(int ipinr
, struct pt_regs
*regs
)
619 handle_IPI(ipinr
, regs
);
622 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
624 unsigned int cpu
= smp_processor_id();
625 struct pt_regs
*old_regs
= set_irq_regs(regs
);
628 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
634 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
637 tick_receive_broadcast();
648 generic_smp_call_function_interrupt();
652 case IPI_CALL_FUNC_SINGLE
:
654 generic_smp_call_function_single_interrupt();
665 printk(KERN_CRIT
"CPU%u: Unknown IPI message 0x%x\n",
669 set_irq_regs(old_regs
);
672 void smp_send_reschedule(int cpu
)
674 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
677 void smp_send_stop(void)
679 unsigned long timeout
;
682 cpumask_copy(&mask
, cpu_online_mask
);
683 cpumask_clear_cpu(smp_processor_id(), &mask
);
684 if (!cpumask_empty(&mask
))
685 smp_cross_call(&mask
, IPI_CPU_STOP
);
687 /* Wait up to one second for other CPUs to stop */
688 timeout
= USEC_PER_SEC
;
689 while (num_online_cpus() > 1 && timeout
--)
692 if (num_online_cpus() > 1)
693 pr_warning("SMP: failed to stop secondary CPUs\n");
699 int setup_profiling_timer(unsigned int multiplier
)
704 #ifdef CONFIG_CPU_FREQ
706 static DEFINE_PER_CPU(unsigned long, l_p_j_ref
);
707 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq
);
708 static unsigned long global_l_p_j_ref
;
709 static unsigned long global_l_p_j_ref_freq
;
711 static int cpufreq_callback(struct notifier_block
*nb
,
712 unsigned long val
, void *data
)
714 struct cpufreq_freqs
*freq
= data
;
717 if (freq
->flags
& CPUFREQ_CONST_LOOPS
)
720 if (!per_cpu(l_p_j_ref
, cpu
)) {
721 per_cpu(l_p_j_ref
, cpu
) =
722 per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
723 per_cpu(l_p_j_ref_freq
, cpu
) = freq
->old
;
724 if (!global_l_p_j_ref
) {
725 global_l_p_j_ref
= loops_per_jiffy
;
726 global_l_p_j_ref_freq
= freq
->old
;
730 if ((val
== CPUFREQ_PRECHANGE
&& freq
->old
< freq
->new) ||
731 (val
== CPUFREQ_POSTCHANGE
&& freq
->old
> freq
->new) ||
732 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
733 loops_per_jiffy
= cpufreq_scale(global_l_p_j_ref
,
734 global_l_p_j_ref_freq
,
736 per_cpu(cpu_data
, cpu
).loops_per_jiffy
=
737 cpufreq_scale(per_cpu(l_p_j_ref
, cpu
),
738 per_cpu(l_p_j_ref_freq
, cpu
),
744 static struct notifier_block cpufreq_notifier
= {
745 .notifier_call
= cpufreq_callback
,
748 static int __init
register_cpufreq_notifier(void)
750 return cpufreq_register_notifier(&cpufreq_notifier
,
751 CPUFREQ_TRANSITION_NOTIFIER
);
753 core_initcall(register_cpufreq_notifier
);