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 int __cpuinit
boot_secondary(unsigned int cpu
, struct task_struct
*idle
)
130 if (smp_ops
.smp_boot_secondary
)
131 return smp_ops
.smp_boot_secondary(cpu
, idle
);
135 #ifdef CONFIG_HOTPLUG_CPU
136 static void percpu_timer_stop(void);
138 static int platform_cpu_kill(unsigned int cpu
)
140 if (smp_ops
.cpu_kill
)
141 return smp_ops
.cpu_kill(cpu
);
145 static int platform_cpu_disable(unsigned int cpu
)
147 if (smp_ops
.cpu_disable
)
148 return smp_ops
.cpu_disable(cpu
);
151 * By default, allow disabling all CPUs except the first one,
152 * since this is special on a lot of platforms, e.g. because
153 * of clock tick interrupts.
155 return cpu
== 0 ? -EPERM
: 0;
158 * __cpu_disable runs on the processor to be shutdown.
160 int __cpuinit
__cpu_disable(void)
162 unsigned int cpu
= smp_processor_id();
165 ret
= platform_cpu_disable(cpu
);
170 * Take this CPU offline. Once we clear this, we can't return,
171 * and we must not schedule until we're ready to give up the cpu.
173 set_cpu_online(cpu
, false);
176 * OK - migrate IRQs away from this CPU
181 * Stop the local timer for this CPU.
186 * Flush user cache and TLB mappings, and then remove this CPU
187 * from the vm mask set of all processes.
189 * Caches are flushed to the Level of Unification Inner Shareable
190 * to write-back dirty lines to unified caches shared by all CPUs.
193 local_flush_tlb_all();
195 clear_tasks_mm_cpumask(cpu
);
200 static DECLARE_COMPLETION(cpu_died
);
203 * called on the thread which is asking for a CPU to be shutdown -
204 * waits until shutdown has completed, or it is timed out.
206 void __cpuinit
__cpu_die(unsigned int cpu
)
208 if (!wait_for_completion_timeout(&cpu_died
, msecs_to_jiffies(5000))) {
209 pr_err("CPU%u: cpu didn't die\n", cpu
);
212 printk(KERN_NOTICE
"CPU%u: shutdown\n", cpu
);
214 if (!platform_cpu_kill(cpu
))
215 printk("CPU%u: unable to kill\n", cpu
);
219 * Called from the idle thread for the CPU which has been shutdown.
221 * Note that we disable IRQs here, but do not re-enable them
222 * before returning to the caller. This is also the behaviour
223 * of the other hotplug-cpu capable cores, so presumably coming
224 * out of idle fixes this.
226 void __ref
cpu_die(void)
228 unsigned int cpu
= smp_processor_id();
235 /* Tell __cpu_die() that this CPU is now safe to dispose of */
236 RCU_NONIDLE(complete(&cpu_died
));
239 * actual CPU shutdown procedure is at least platform (if not
243 smp_ops
.cpu_die(cpu
);
246 * Do not return to the idle loop - jump back to the secondary
247 * cpu initialisation. There's some initialisation which needs
248 * to be repeated to undo the effects of taking the CPU offline.
250 __asm__("mov sp, %0\n"
252 " b secondary_start_kernel"
254 : "r" (task_stack_page(current
) + THREAD_SIZE
- 8));
256 #endif /* CONFIG_HOTPLUG_CPU */
259 * Called by both boot and secondaries to move global data into
260 * per-processor storage.
262 static void __cpuinit
smp_store_cpu_info(unsigned int cpuid
)
264 struct cpuinfo_arm
*cpu_info
= &per_cpu(cpu_data
, cpuid
);
266 cpu_info
->loops_per_jiffy
= loops_per_jiffy
;
267 cpu_info
->cpuid
= read_cpuid_id();
269 store_cpu_topology(cpuid
);
272 static void percpu_timer_setup(void);
275 * This is the secondary CPU boot entry. We're using this CPUs
276 * idle thread stack, but a set of temporary page tables.
278 asmlinkage
void __cpuinit
secondary_start_kernel(void)
280 struct mm_struct
*mm
= &init_mm
;
284 * The identity mapping is uncached (strongly ordered), so
285 * switch away from it before attempting any exclusive accesses.
287 cpu_switch_mm(mm
->pgd
, mm
);
288 enter_lazy_tlb(mm
, current
);
289 local_flush_tlb_all();
292 * All kernel threads share the same mm context; grab a
293 * reference and switch to it.
295 cpu
= smp_processor_id();
296 atomic_inc(&mm
->mm_count
);
297 current
->active_mm
= mm
;
298 cpumask_set_cpu(cpu
, mm_cpumask(mm
));
302 printk("CPU%u: Booted secondary processor\n", cpu
);
305 trace_hardirqs_off();
308 * Give the platform a chance to do its own initialisation.
310 if (smp_ops
.smp_secondary_init
)
311 smp_ops
.smp_secondary_init(cpu
);
313 notify_cpu_starting(cpu
);
317 smp_store_cpu_info(cpu
);
320 * OK, now it's safe to let the boot CPU continue. Wait for
321 * the CPU migration code to notice that the CPU is online
322 * before we continue - which happens after __cpu_up returns.
324 set_cpu_online(cpu
, true);
325 complete(&cpu_running
);
328 * Setup the percpu timer for this CPU.
330 percpu_timer_setup();
336 * OK, it's off to the idle thread for us
341 void __init
smp_cpus_done(unsigned int max_cpus
)
344 unsigned long bogosum
= 0;
346 for_each_online_cpu(cpu
)
347 bogosum
+= per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
349 printk(KERN_INFO
"SMP: Total of %d processors activated "
350 "(%lu.%02lu BogoMIPS).\n",
352 bogosum
/ (500000/HZ
),
353 (bogosum
/ (5000/HZ
)) % 100);
358 void __init
smp_prepare_boot_cpu(void)
360 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
363 void __init
smp_prepare_cpus(unsigned int max_cpus
)
365 unsigned int ncores
= num_possible_cpus();
369 smp_store_cpu_info(smp_processor_id());
372 * are we trying to boot more cores than exist?
374 if (max_cpus
> ncores
)
376 if (ncores
> 1 && max_cpus
) {
378 * Enable the local timer or broadcast device for the
379 * boot CPU, but only if we have more than one CPU.
381 percpu_timer_setup();
384 * Initialise the present map, which describes the set of CPUs
385 * actually populated at the present time. A platform should
386 * re-initialize the map in the platforms smp_prepare_cpus()
387 * if present != possible (e.g. physical hotplug).
389 init_cpu_present(cpu_possible_mask
);
392 * Initialise the SCU if there are more than one CPU
393 * and let them know where to start.
395 if (smp_ops
.smp_prepare_cpus
)
396 smp_ops
.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))
408 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
410 smp_cross_call(mask
, IPI_CALL_FUNC
);
413 void arch_send_wakeup_ipi_mask(const struct cpumask
*mask
)
415 smp_cross_call(mask
, IPI_WAKEUP
);
418 void arch_send_call_function_single_ipi(int cpu
)
420 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC_SINGLE
);
423 static const char *ipi_types
[NR_IPI
] = {
424 #define S(x,s) [x] = s
425 S(IPI_WAKEUP
, "CPU wakeup interrupts"),
426 S(IPI_TIMER
, "Timer broadcast interrupts"),
427 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
428 S(IPI_CALL_FUNC
, "Function call interrupts"),
429 S(IPI_CALL_FUNC_SINGLE
, "Single function call interrupts"),
430 S(IPI_CPU_STOP
, "CPU stop interrupts"),
433 void show_ipi_list(struct seq_file
*p
, int prec
)
437 for (i
= 0; i
< NR_IPI
; i
++) {
438 seq_printf(p
, "%*s%u: ", prec
- 1, "IPI", i
);
440 for_each_online_cpu(cpu
)
441 seq_printf(p
, "%10u ",
442 __get_irq_stat(cpu
, ipi_irqs
[i
]));
444 seq_printf(p
, " %s\n", ipi_types
[i
]);
448 u64
smp_irq_stat_cpu(unsigned int cpu
)
453 for (i
= 0; i
< NR_IPI
; i
++)
454 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
460 * Timer (local or broadcast) support
462 static DEFINE_PER_CPU(struct clock_event_device
, percpu_clockevent
);
464 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
465 void tick_broadcast(const struct cpumask
*mask
)
467 smp_cross_call(mask
, IPI_TIMER
);
471 static void broadcast_timer_set_mode(enum clock_event_mode mode
,
472 struct clock_event_device
*evt
)
476 static void __cpuinit
broadcast_timer_setup(struct clock_event_device
*evt
)
478 evt
->name
= "dummy_timer";
479 evt
->features
= CLOCK_EVT_FEAT_ONESHOT
|
480 CLOCK_EVT_FEAT_PERIODIC
|
481 CLOCK_EVT_FEAT_DUMMY
;
484 evt
->set_mode
= broadcast_timer_set_mode
;
486 clockevents_register_device(evt
);
489 static struct local_timer_ops
*lt_ops
;
491 #ifdef CONFIG_LOCAL_TIMERS
492 int local_timer_register(struct local_timer_ops
*ops
)
494 if (!is_smp() || !setup_max_cpus
)
505 static void __cpuinit
percpu_timer_setup(void)
507 unsigned int cpu
= smp_processor_id();
508 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
510 evt
->cpumask
= cpumask_of(cpu
);
512 if (!lt_ops
|| lt_ops
->setup(evt
))
513 broadcast_timer_setup(evt
);
516 #ifdef CONFIG_HOTPLUG_CPU
518 * The generic clock events code purposely does not stop the local timer
519 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
522 static void percpu_timer_stop(void)
524 unsigned int cpu
= smp_processor_id();
525 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
532 static DEFINE_RAW_SPINLOCK(stop_lock
);
535 * ipi_cpu_stop - handle IPI from smp_send_stop()
537 static void ipi_cpu_stop(unsigned int cpu
)
539 if (system_state
== SYSTEM_BOOTING
||
540 system_state
== SYSTEM_RUNNING
) {
541 raw_spin_lock(&stop_lock
);
542 printk(KERN_CRIT
"CPU%u: stopping\n", cpu
);
544 raw_spin_unlock(&stop_lock
);
547 set_cpu_online(cpu
, false);
557 * Main handler for inter-processor interrupts
559 asmlinkage
void __exception_irq_entry
do_IPI(int ipinr
, struct pt_regs
*regs
)
561 handle_IPI(ipinr
, regs
);
564 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
566 unsigned int cpu
= smp_processor_id();
567 struct pt_regs
*old_regs
= set_irq_regs(regs
);
570 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
576 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
579 tick_receive_broadcast();
590 generic_smp_call_function_interrupt();
594 case IPI_CALL_FUNC_SINGLE
:
596 generic_smp_call_function_single_interrupt();
607 printk(KERN_CRIT
"CPU%u: Unknown IPI message 0x%x\n",
611 set_irq_regs(old_regs
);
614 void smp_send_reschedule(int cpu
)
616 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
619 #ifdef CONFIG_HOTPLUG_CPU
620 static void smp_kill_cpus(cpumask_t
*mask
)
623 for_each_cpu(cpu
, mask
)
624 platform_cpu_kill(cpu
);
627 static void smp_kill_cpus(cpumask_t
*mask
) { }
630 void smp_send_stop(void)
632 unsigned long timeout
;
635 cpumask_copy(&mask
, cpu_online_mask
);
636 cpumask_clear_cpu(smp_processor_id(), &mask
);
637 if (!cpumask_empty(&mask
))
638 smp_cross_call(&mask
, IPI_CPU_STOP
);
640 /* Wait up to one second for other CPUs to stop */
641 timeout
= USEC_PER_SEC
;
642 while (num_online_cpus() > 1 && timeout
--)
645 if (num_online_cpus() > 1)
646 pr_warning("SMP: failed to stop secondary CPUs\n");
648 smp_kill_cpus(&mask
);
654 int setup_profiling_timer(unsigned int multiplier
)
659 #ifdef CONFIG_CPU_FREQ
661 static DEFINE_PER_CPU(unsigned long, l_p_j_ref
);
662 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq
);
663 static unsigned long global_l_p_j_ref
;
664 static unsigned long global_l_p_j_ref_freq
;
666 static int cpufreq_callback(struct notifier_block
*nb
,
667 unsigned long val
, void *data
)
669 struct cpufreq_freqs
*freq
= data
;
672 if (freq
->flags
& CPUFREQ_CONST_LOOPS
)
675 if (arm_delay_ops
.const_clock
)
678 if (!per_cpu(l_p_j_ref
, cpu
)) {
679 per_cpu(l_p_j_ref
, cpu
) =
680 per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
681 per_cpu(l_p_j_ref_freq
, cpu
) = freq
->old
;
682 if (!global_l_p_j_ref
) {
683 global_l_p_j_ref
= loops_per_jiffy
;
684 global_l_p_j_ref_freq
= freq
->old
;
688 if ((val
== CPUFREQ_PRECHANGE
&& freq
->old
< freq
->new) ||
689 (val
== CPUFREQ_POSTCHANGE
&& freq
->old
> freq
->new) ||
690 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
691 loops_per_jiffy
= cpufreq_scale(global_l_p_j_ref
,
692 global_l_p_j_ref_freq
,
694 per_cpu(cpu_data
, cpu
).loops_per_jiffy
=
695 cpufreq_scale(per_cpu(l_p_j_ref
, cpu
),
696 per_cpu(l_p_j_ref_freq
, cpu
),
702 static struct notifier_block cpufreq_notifier
= {
703 .notifier_call
= cpufreq_callback
,
706 static int __init
register_cpufreq_notifier(void)
708 return cpufreq_register_notifier(&cpufreq_notifier
,
709 CPUFREQ_TRANSITION_NOTIFIER
);
711 core_initcall(register_cpufreq_notifier
);