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>
50 * as from 2.5, kernels no longer have an init_tasks structure
51 * so we need some other way of telling a new secondary core
52 * where to place its SVC stack
54 struct secondary_data secondary_data
;
57 * control for which core is the next to come out of the secondary
60 volatile int __cpuinitdata pen_release
= -1;
71 static DECLARE_COMPLETION(cpu_running
);
73 static struct smp_operations smp_ops
;
75 void __init
smp_set_ops(struct smp_operations
*ops
)
81 int __cpuinit
__cpu_up(unsigned int cpu
, struct task_struct
*idle
)
86 * We need to tell the secondary core where to find
87 * its stack and the page tables.
89 secondary_data
.stack
= task_stack_page(idle
) + THREAD_START_SP
;
90 secondary_data
.pgdir
= virt_to_phys(idmap_pgd
);
91 secondary_data
.swapper_pg_dir
= virt_to_phys(swapper_pg_dir
);
92 __cpuc_flush_dcache_area(&secondary_data
, sizeof(secondary_data
));
93 outer_clean_range(__pa(&secondary_data
), __pa(&secondary_data
+ 1));
96 * Now bring the CPU into our world.
98 ret
= boot_secondary(cpu
, idle
);
101 * CPU was successfully started, wait for it
102 * to come online or time out.
104 wait_for_completion_timeout(&cpu_running
,
105 msecs_to_jiffies(1000));
107 if (!cpu_online(cpu
)) {
108 pr_crit("CPU%u: failed to come online\n", cpu
);
112 pr_err("CPU%u: failed to boot: %d\n", cpu
, ret
);
115 secondary_data
.stack
= NULL
;
116 secondary_data
.pgdir
= 0;
121 /* platform specific SMP operations */
122 void __init
smp_init_cpus(void)
124 if (smp_ops
.smp_init_cpus
)
125 smp_ops
.smp_init_cpus();
128 static void __init
platform_smp_prepare_cpus(unsigned int max_cpus
)
130 if (smp_ops
.smp_prepare_cpus
)
131 smp_ops
.smp_prepare_cpus(max_cpus
);
134 static void __cpuinit
platform_secondary_init(unsigned int cpu
)
136 if (smp_ops
.smp_secondary_init
)
137 smp_ops
.smp_secondary_init(cpu
);
140 int __cpuinit
boot_secondary(unsigned int cpu
, struct task_struct
*idle
)
142 if (smp_ops
.smp_boot_secondary
)
143 return smp_ops
.smp_boot_secondary(cpu
, idle
);
147 #ifdef CONFIG_HOTPLUG_CPU
148 static void percpu_timer_stop(void);
150 static int platform_cpu_kill(unsigned int cpu
)
152 if (smp_ops
.cpu_kill
)
153 return smp_ops
.cpu_kill(cpu
);
157 static void platform_cpu_die(unsigned int cpu
)
160 smp_ops
.cpu_die(cpu
);
163 static int platform_cpu_disable(unsigned int cpu
)
165 if (smp_ops
.cpu_disable
)
166 return smp_ops
.cpu_disable(cpu
);
169 * By default, allow disabling all CPUs except the first one,
170 * since this is special on a lot of platforms, e.g. because
171 * of clock tick interrupts.
173 return cpu
== 0 ? -EPERM
: 0;
176 * __cpu_disable runs on the processor to be shutdown.
178 int __cpuinit
__cpu_disable(void)
180 unsigned int cpu
= smp_processor_id();
183 ret
= platform_cpu_disable(cpu
);
188 * Take this CPU offline. Once we clear this, we can't return,
189 * and we must not schedule until we're ready to give up the cpu.
191 set_cpu_online(cpu
, false);
194 * OK - migrate IRQs away from this CPU
199 * Stop the local timer for this CPU.
204 * Flush user cache and TLB mappings, and then remove this CPU
205 * from the vm mask set of all processes.
207 * Caches are flushed to the Level of Unification Inner Shareable
208 * to write-back dirty lines to unified caches shared by all CPUs.
211 local_flush_tlb_all();
213 clear_tasks_mm_cpumask(cpu
);
218 static DECLARE_COMPLETION(cpu_died
);
221 * called on the thread which is asking for a CPU to be shutdown -
222 * waits until shutdown has completed, or it is timed out.
224 void __cpuinit
__cpu_die(unsigned int cpu
)
226 if (!wait_for_completion_timeout(&cpu_died
, msecs_to_jiffies(5000))) {
227 pr_err("CPU%u: cpu didn't die\n", cpu
);
230 printk(KERN_NOTICE
"CPU%u: shutdown\n", cpu
);
232 if (!platform_cpu_kill(cpu
))
233 printk("CPU%u: unable to kill\n", cpu
);
237 * Called from the idle thread for the CPU which has been shutdown.
239 * Note that we disable IRQs here, but do not re-enable them
240 * before returning to the caller. This is also the behaviour
241 * of the other hotplug-cpu capable cores, so presumably coming
242 * out of idle fixes this.
244 void __ref
cpu_die(void)
246 unsigned int cpu
= smp_processor_id();
253 /* Tell __cpu_die() that this CPU is now safe to dispose of */
254 RCU_NONIDLE(complete(&cpu_died
));
257 * actual CPU shutdown procedure is at least platform (if not
260 platform_cpu_die(cpu
);
263 * Do not return to the idle loop - jump back to the secondary
264 * cpu initialisation. There's some initialisation which needs
265 * to be repeated to undo the effects of taking the CPU offline.
267 __asm__("mov sp, %0\n"
269 " b secondary_start_kernel"
271 : "r" (task_stack_page(current
) + THREAD_SIZE
- 8));
273 #endif /* CONFIG_HOTPLUG_CPU */
276 * Called by both boot and secondaries to move global data into
277 * per-processor storage.
279 static void __cpuinit
smp_store_cpu_info(unsigned int cpuid
)
281 struct cpuinfo_arm
*cpu_info
= &per_cpu(cpu_data
, cpuid
);
283 cpu_info
->loops_per_jiffy
= loops_per_jiffy
;
284 cpu_info
->cpuid
= read_cpuid_id();
286 store_cpu_topology(cpuid
);
289 static void percpu_timer_setup(void);
292 * This is the secondary CPU boot entry. We're using this CPUs
293 * idle thread stack, but a set of temporary page tables.
295 asmlinkage
void __cpuinit
secondary_start_kernel(void)
297 struct mm_struct
*mm
= &init_mm
;
301 * The identity mapping is uncached (strongly ordered), so
302 * switch away from it before attempting any exclusive accesses.
304 cpu_switch_mm(mm
->pgd
, mm
);
305 enter_lazy_tlb(mm
, current
);
306 local_flush_tlb_all();
309 * All kernel threads share the same mm context; grab a
310 * reference and switch to it.
312 cpu
= smp_processor_id();
313 atomic_inc(&mm
->mm_count
);
314 current
->active_mm
= mm
;
315 cpumask_set_cpu(cpu
, mm_cpumask(mm
));
319 printk("CPU%u: Booted secondary processor\n", cpu
);
322 trace_hardirqs_off();
325 * Give the platform a chance to do its own initialisation.
327 platform_secondary_init(cpu
);
329 notify_cpu_starting(cpu
);
333 smp_store_cpu_info(cpu
);
336 * OK, now it's safe to let the boot CPU continue. Wait for
337 * the CPU migration code to notice that the CPU is online
338 * before we continue - which happens after __cpu_up returns.
340 set_cpu_online(cpu
, true);
341 complete(&cpu_running
);
344 * Setup the percpu timer for this CPU.
346 percpu_timer_setup();
352 * OK, it's off to the idle thread for us
357 void __init
smp_cpus_done(unsigned int max_cpus
)
360 unsigned long bogosum
= 0;
362 for_each_online_cpu(cpu
)
363 bogosum
+= per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
365 printk(KERN_INFO
"SMP: Total of %d processors activated "
366 "(%lu.%02lu BogoMIPS).\n",
368 bogosum
/ (500000/HZ
),
369 (bogosum
/ (5000/HZ
)) % 100);
374 void __init
smp_prepare_boot_cpu(void)
376 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
379 void __init
smp_prepare_cpus(unsigned int max_cpus
)
381 unsigned int ncores
= num_possible_cpus();
385 smp_store_cpu_info(smp_processor_id());
388 * are we trying to boot more cores than exist?
390 if (max_cpus
> ncores
)
392 if (ncores
> 1 && max_cpus
) {
394 * Enable the local timer or broadcast device for the
395 * boot CPU, but only if we have more than one CPU.
397 percpu_timer_setup();
400 * Initialise the present map, which describes the set of CPUs
401 * actually populated at the present time. A platform should
402 * re-initialize the map in platform_smp_prepare_cpus() if
403 * present != possible (e.g. physical hotplug).
405 init_cpu_present(cpu_possible_mask
);
408 * Initialise the SCU if there are more than one CPU
409 * and let them know where to start.
411 platform_smp_prepare_cpus(max_cpus
);
415 static void (*smp_cross_call
)(const struct cpumask
*, unsigned int);
417 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
422 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
424 smp_cross_call(mask
, IPI_CALL_FUNC
);
427 void arch_send_wakeup_ipi_mask(const struct cpumask
*mask
)
429 smp_cross_call(mask
, IPI_WAKEUP
);
432 void arch_send_call_function_single_ipi(int cpu
)
434 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC_SINGLE
);
437 static const char *ipi_types
[NR_IPI
] = {
438 #define S(x,s) [x] = s
439 S(IPI_WAKEUP
, "CPU wakeup interrupts"),
440 S(IPI_TIMER
, "Timer broadcast interrupts"),
441 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
442 S(IPI_CALL_FUNC
, "Function call interrupts"),
443 S(IPI_CALL_FUNC_SINGLE
, "Single function call interrupts"),
444 S(IPI_CPU_STOP
, "CPU stop interrupts"),
447 void show_ipi_list(struct seq_file
*p
, int prec
)
451 for (i
= 0; i
< NR_IPI
; i
++) {
452 seq_printf(p
, "%*s%u: ", prec
- 1, "IPI", i
);
454 for_each_online_cpu(cpu
)
455 seq_printf(p
, "%10u ",
456 __get_irq_stat(cpu
, ipi_irqs
[i
]));
458 seq_printf(p
, " %s\n", ipi_types
[i
]);
462 u64
smp_irq_stat_cpu(unsigned int cpu
)
467 for (i
= 0; i
< NR_IPI
; i
++)
468 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
474 * Timer (local or broadcast) support
476 static DEFINE_PER_CPU(struct clock_event_device
, percpu_clockevent
);
478 static void ipi_timer(void)
480 struct clock_event_device
*evt
= &__get_cpu_var(percpu_clockevent
);
481 evt
->event_handler(evt
);
484 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
485 static void smp_timer_broadcast(const struct cpumask
*mask
)
487 smp_cross_call(mask
, IPI_TIMER
);
490 #define smp_timer_broadcast NULL
493 static void broadcast_timer_set_mode(enum clock_event_mode mode
,
494 struct clock_event_device
*evt
)
498 static void __cpuinit
broadcast_timer_setup(struct clock_event_device
*evt
)
500 evt
->name
= "dummy_timer";
501 evt
->features
= CLOCK_EVT_FEAT_ONESHOT
|
502 CLOCK_EVT_FEAT_PERIODIC
|
503 CLOCK_EVT_FEAT_DUMMY
;
506 evt
->set_mode
= broadcast_timer_set_mode
;
508 clockevents_register_device(evt
);
511 static struct local_timer_ops
*lt_ops
;
513 #ifdef CONFIG_LOCAL_TIMERS
514 int local_timer_register(struct local_timer_ops
*ops
)
516 if (!is_smp() || !setup_max_cpus
)
527 static void __cpuinit
percpu_timer_setup(void)
529 unsigned int cpu
= smp_processor_id();
530 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
532 evt
->cpumask
= cpumask_of(cpu
);
533 evt
->broadcast
= smp_timer_broadcast
;
535 if (!lt_ops
|| lt_ops
->setup(evt
))
536 broadcast_timer_setup(evt
);
539 #ifdef CONFIG_HOTPLUG_CPU
541 * The generic clock events code purposely does not stop the local timer
542 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
545 static void percpu_timer_stop(void)
547 unsigned int cpu
= smp_processor_id();
548 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
555 static DEFINE_RAW_SPINLOCK(stop_lock
);
558 * ipi_cpu_stop - handle IPI from smp_send_stop()
560 static void ipi_cpu_stop(unsigned int cpu
)
562 if (system_state
== SYSTEM_BOOTING
||
563 system_state
== SYSTEM_RUNNING
) {
564 raw_spin_lock(&stop_lock
);
565 printk(KERN_CRIT
"CPU%u: stopping\n", cpu
);
567 raw_spin_unlock(&stop_lock
);
570 set_cpu_online(cpu
, false);
580 * Main handler for inter-processor interrupts
582 asmlinkage
void __exception_irq_entry
do_IPI(int ipinr
, struct pt_regs
*regs
)
584 handle_IPI(ipinr
, regs
);
587 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
589 unsigned int cpu
= smp_processor_id();
590 struct pt_regs
*old_regs
= set_irq_regs(regs
);
593 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
611 generic_smp_call_function_interrupt();
615 case IPI_CALL_FUNC_SINGLE
:
617 generic_smp_call_function_single_interrupt();
628 printk(KERN_CRIT
"CPU%u: Unknown IPI message 0x%x\n",
632 set_irq_regs(old_regs
);
635 void smp_send_reschedule(int cpu
)
637 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
640 #ifdef CONFIG_HOTPLUG_CPU
641 static void smp_kill_cpus(cpumask_t
*mask
)
644 for_each_cpu(cpu
, mask
)
645 platform_cpu_kill(cpu
);
648 static void smp_kill_cpus(cpumask_t
*mask
) { }
651 void smp_send_stop(void)
653 unsigned long timeout
;
656 cpumask_copy(&mask
, cpu_online_mask
);
657 cpumask_clear_cpu(smp_processor_id(), &mask
);
658 if (!cpumask_empty(&mask
))
659 smp_cross_call(&mask
, IPI_CPU_STOP
);
661 /* Wait up to one second for other CPUs to stop */
662 timeout
= USEC_PER_SEC
;
663 while (num_online_cpus() > 1 && timeout
--)
666 if (num_online_cpus() > 1)
667 pr_warning("SMP: failed to stop secondary CPUs\n");
669 smp_kill_cpus(&mask
);
675 int setup_profiling_timer(unsigned int multiplier
)
680 #ifdef CONFIG_CPU_FREQ
682 static DEFINE_PER_CPU(unsigned long, l_p_j_ref
);
683 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq
);
684 static unsigned long global_l_p_j_ref
;
685 static unsigned long global_l_p_j_ref_freq
;
687 static int cpufreq_callback(struct notifier_block
*nb
,
688 unsigned long val
, void *data
)
690 struct cpufreq_freqs
*freq
= data
;
693 if (freq
->flags
& CPUFREQ_CONST_LOOPS
)
696 if (!per_cpu(l_p_j_ref
, cpu
)) {
697 per_cpu(l_p_j_ref
, cpu
) =
698 per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
699 per_cpu(l_p_j_ref_freq
, cpu
) = freq
->old
;
700 if (!global_l_p_j_ref
) {
701 global_l_p_j_ref
= loops_per_jiffy
;
702 global_l_p_j_ref_freq
= freq
->old
;
706 if ((val
== CPUFREQ_PRECHANGE
&& freq
->old
< freq
->new) ||
707 (val
== CPUFREQ_POSTCHANGE
&& freq
->old
> freq
->new) ||
708 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
709 loops_per_jiffy
= cpufreq_scale(global_l_p_j_ref
,
710 global_l_p_j_ref_freq
,
712 per_cpu(cpu_data
, cpu
).loops_per_jiffy
=
713 cpufreq_scale(per_cpu(l_p_j_ref
, cpu
),
714 per_cpu(l_p_j_ref_freq
, cpu
),
720 static struct notifier_block cpufreq_notifier
= {
721 .notifier_call
= cpufreq_callback
,
724 static int __init
register_cpufreq_notifier(void)
726 return cpufreq_register_notifier(&cpufreq_notifier
,
727 CPUFREQ_TRANSITION_NOTIFIER
);
729 core_initcall(register_cpufreq_notifier
);