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 static DECLARE_COMPLETION(cpu_running
);
63 int __cpuinit
__cpu_up(unsigned int cpu
)
65 struct cpuinfo_arm
*ci
= &per_cpu(cpu_data
, cpu
);
66 struct task_struct
*idle
= ci
->idle
;
70 * Spawn a new process manually, if not already done.
71 * Grab a pointer to its task struct so we can mess with it
74 idle
= fork_idle(cpu
);
76 printk(KERN_ERR
"CPU%u: fork() failed\n", cpu
);
82 * Since this idle thread is being re-used, call
83 * init_idle() to reinitialize the thread structure.
89 * We need to tell the secondary core where to find
90 * its stack and the page tables.
92 secondary_data
.stack
= task_stack_page(idle
) + THREAD_START_SP
;
93 secondary_data
.pgdir
= virt_to_phys(idmap_pgd
);
94 secondary_data
.swapper_pg_dir
= virt_to_phys(swapper_pg_dir
);
95 __cpuc_flush_dcache_area(&secondary_data
, sizeof(secondary_data
));
96 outer_clean_range(__pa(&secondary_data
), __pa(&secondary_data
+ 1));
99 * Now bring the CPU into our world.
101 ret
= boot_secondary(cpu
, idle
);
104 * CPU was successfully started, wait for it
105 * to come online or time out.
107 wait_for_completion_timeout(&cpu_running
,
108 msecs_to_jiffies(1000));
110 if (!cpu_online(cpu
)) {
111 pr_crit("CPU%u: failed to come online\n", cpu
);
115 pr_err("CPU%u: failed to boot: %d\n", cpu
, ret
);
118 secondary_data
.stack
= NULL
;
119 secondary_data
.pgdir
= 0;
124 #ifdef CONFIG_HOTPLUG_CPU
125 static void percpu_timer_stop(void);
128 * __cpu_disable runs on the processor to be shutdown.
130 int __cpu_disable(void)
132 unsigned int cpu
= smp_processor_id();
133 struct task_struct
*p
;
136 ret
= platform_cpu_disable(cpu
);
141 * Take this CPU offline. Once we clear this, we can't return,
142 * and we must not schedule until we're ready to give up the cpu.
144 set_cpu_online(cpu
, false);
147 * OK - migrate IRQs away from this CPU
152 * Stop the local timer for this CPU.
157 * Flush user cache and TLB mappings, and then remove this CPU
158 * from the vm mask set of all processes.
161 local_flush_tlb_all();
163 read_lock(&tasklist_lock
);
164 for_each_process(p
) {
166 cpumask_clear_cpu(cpu
, mm_cpumask(p
->mm
));
168 read_unlock(&tasklist_lock
);
173 static DECLARE_COMPLETION(cpu_died
);
176 * called on the thread which is asking for a CPU to be shutdown -
177 * waits until shutdown has completed, or it is timed out.
179 void __cpu_die(unsigned int cpu
)
181 if (!wait_for_completion_timeout(&cpu_died
, msecs_to_jiffies(5000))) {
182 pr_err("CPU%u: cpu didn't die\n", cpu
);
185 printk(KERN_NOTICE
"CPU%u: shutdown\n", cpu
);
187 if (!platform_cpu_kill(cpu
))
188 printk("CPU%u: unable to kill\n", cpu
);
192 * Called from the idle thread for the CPU which has been shutdown.
194 * Note that we disable IRQs here, but do not re-enable them
195 * before returning to the caller. This is also the behaviour
196 * of the other hotplug-cpu capable cores, so presumably coming
197 * out of idle fixes this.
199 void __ref
cpu_die(void)
201 unsigned int cpu
= smp_processor_id();
208 /* Tell __cpu_die() that this CPU is now safe to dispose of */
212 * actual CPU shutdown procedure is at least platform (if not
215 platform_cpu_die(cpu
);
218 * Do not return to the idle loop - jump back to the secondary
219 * cpu initialisation. There's some initialisation which needs
220 * to be repeated to undo the effects of taking the CPU offline.
222 __asm__("mov sp, %0\n"
224 " b secondary_start_kernel"
226 : "r" (task_stack_page(current
) + THREAD_SIZE
- 8));
228 #endif /* CONFIG_HOTPLUG_CPU */
231 * Called by both boot and secondaries to move global data into
232 * per-processor storage.
234 static void __cpuinit
smp_store_cpu_info(unsigned int cpuid
)
236 struct cpuinfo_arm
*cpu_info
= &per_cpu(cpu_data
, cpuid
);
238 cpu_info
->loops_per_jiffy
= loops_per_jiffy
;
240 store_cpu_topology(cpuid
);
243 static void percpu_timer_setup(void);
246 * This is the secondary CPU boot entry. We're using this CPUs
247 * idle thread stack, but a set of temporary page tables.
249 asmlinkage
void __cpuinit
secondary_start_kernel(void)
251 struct mm_struct
*mm
= &init_mm
;
252 unsigned int cpu
= smp_processor_id();
254 printk("CPU%u: Booted secondary processor\n", cpu
);
257 * All kernel threads share the same mm context; grab a
258 * reference and switch to it.
260 atomic_inc(&mm
->mm_count
);
261 current
->active_mm
= mm
;
262 cpumask_set_cpu(cpu
, mm_cpumask(mm
));
263 cpu_switch_mm(mm
->pgd
, mm
);
264 enter_lazy_tlb(mm
, current
);
265 local_flush_tlb_all();
269 trace_hardirqs_off();
272 * Give the platform a chance to do its own initialisation.
274 platform_secondary_init(cpu
);
276 notify_cpu_starting(cpu
);
280 smp_store_cpu_info(cpu
);
283 * OK, now it's safe to let the boot CPU continue. Wait for
284 * the CPU migration code to notice that the CPU is online
285 * before we continue - which happens after __cpu_up returns.
287 set_cpu_online(cpu
, true);
288 complete(&cpu_running
);
291 * Setup the percpu timer for this CPU.
293 percpu_timer_setup();
299 * OK, it's off to the idle thread for us
304 void __init
smp_cpus_done(unsigned int max_cpus
)
307 unsigned long bogosum
= 0;
309 for_each_online_cpu(cpu
)
310 bogosum
+= per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
312 printk(KERN_INFO
"SMP: Total of %d processors activated "
313 "(%lu.%02lu BogoMIPS).\n",
315 bogosum
/ (500000/HZ
),
316 (bogosum
/ (5000/HZ
)) % 100);
319 void __init
smp_prepare_boot_cpu(void)
321 unsigned int cpu
= smp_processor_id();
323 per_cpu(cpu_data
, cpu
).idle
= current
;
326 void __init
smp_prepare_cpus(unsigned int max_cpus
)
328 unsigned int ncores
= num_possible_cpus();
332 smp_store_cpu_info(smp_processor_id());
335 * are we trying to boot more cores than exist?
337 if (max_cpus
> ncores
)
339 if (ncores
> 1 && max_cpus
) {
341 * Enable the local timer or broadcast device for the
342 * boot CPU, but only if we have more than one CPU.
344 percpu_timer_setup();
347 * Initialise the present map, which describes the set of CPUs
348 * actually populated at the present time. A platform should
349 * re-initialize the map in platform_smp_prepare_cpus() if
350 * present != possible (e.g. physical hotplug).
352 init_cpu_present(cpu_possible_mask
);
355 * Initialise the SCU if there are more than one CPU
356 * and let them know where to start.
358 platform_smp_prepare_cpus(max_cpus
);
362 static void (*smp_cross_call
)(const struct cpumask
*, unsigned int);
364 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
369 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
371 smp_cross_call(mask
, IPI_CALL_FUNC
);
374 void arch_send_call_function_single_ipi(int cpu
)
376 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC_SINGLE
);
379 static const char *ipi_types
[NR_IPI
] = {
380 #define S(x,s) [x - IPI_TIMER] = s
381 S(IPI_TIMER
, "Timer broadcast interrupts"),
382 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
383 S(IPI_CALL_FUNC
, "Function call interrupts"),
384 S(IPI_CALL_FUNC_SINGLE
, "Single function call interrupts"),
385 S(IPI_CPU_STOP
, "CPU stop interrupts"),
388 void show_ipi_list(struct seq_file
*p
, int prec
)
392 for (i
= 0; i
< NR_IPI
; i
++) {
393 seq_printf(p
, "%*s%u: ", prec
- 1, "IPI", i
);
395 for_each_present_cpu(cpu
)
396 seq_printf(p
, "%10u ",
397 __get_irq_stat(cpu
, ipi_irqs
[i
]));
399 seq_printf(p
, " %s\n", ipi_types
[i
]);
403 u64
smp_irq_stat_cpu(unsigned int cpu
)
408 for (i
= 0; i
< NR_IPI
; i
++)
409 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
415 * Timer (local or broadcast) support
417 static DEFINE_PER_CPU(struct clock_event_device
, percpu_clockevent
);
419 static void ipi_timer(void)
421 struct clock_event_device
*evt
= &__get_cpu_var(percpu_clockevent
);
422 evt
->event_handler(evt
);
425 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
426 static void smp_timer_broadcast(const struct cpumask
*mask
)
428 smp_cross_call(mask
, IPI_TIMER
);
431 #define smp_timer_broadcast NULL
434 static void broadcast_timer_set_mode(enum clock_event_mode mode
,
435 struct clock_event_device
*evt
)
439 static void __cpuinit
broadcast_timer_setup(struct clock_event_device
*evt
)
441 evt
->name
= "dummy_timer";
442 evt
->features
= CLOCK_EVT_FEAT_ONESHOT
|
443 CLOCK_EVT_FEAT_PERIODIC
|
444 CLOCK_EVT_FEAT_DUMMY
;
447 evt
->set_mode
= broadcast_timer_set_mode
;
449 clockevents_register_device(evt
);
452 static struct local_timer_ops
*lt_ops
;
454 #ifdef CONFIG_LOCAL_TIMERS
455 int local_timer_register(struct local_timer_ops
*ops
)
465 static void __cpuinit
percpu_timer_setup(void)
467 unsigned int cpu
= smp_processor_id();
468 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
470 evt
->cpumask
= cpumask_of(cpu
);
471 evt
->broadcast
= smp_timer_broadcast
;
473 if (!lt_ops
|| lt_ops
->setup(evt
))
474 broadcast_timer_setup(evt
);
477 #ifdef CONFIG_HOTPLUG_CPU
479 * The generic clock events code purposely does not stop the local timer
480 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
483 static void percpu_timer_stop(void)
485 unsigned int cpu
= smp_processor_id();
486 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
493 static DEFINE_RAW_SPINLOCK(stop_lock
);
496 * ipi_cpu_stop - handle IPI from smp_send_stop()
498 static void ipi_cpu_stop(unsigned int cpu
)
500 if (system_state
== SYSTEM_BOOTING
||
501 system_state
== SYSTEM_RUNNING
) {
502 raw_spin_lock(&stop_lock
);
503 printk(KERN_CRIT
"CPU%u: stopping\n", cpu
);
505 raw_spin_unlock(&stop_lock
);
508 set_cpu_online(cpu
, false);
513 #ifdef CONFIG_HOTPLUG_CPU
514 platform_cpu_kill(cpu
);
522 * Main handler for inter-processor interrupts
524 asmlinkage
void __exception_irq_entry
do_IPI(int ipinr
, struct pt_regs
*regs
)
526 handle_IPI(ipinr
, regs
);
529 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
531 unsigned int cpu
= smp_processor_id();
532 struct pt_regs
*old_regs
= set_irq_regs(regs
);
534 if (ipinr
>= IPI_TIMER
&& ipinr
< IPI_TIMER
+ NR_IPI
)
535 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
- IPI_TIMER
]);
550 generic_smp_call_function_interrupt();
554 case IPI_CALL_FUNC_SINGLE
:
556 generic_smp_call_function_single_interrupt();
567 printk(KERN_CRIT
"CPU%u: Unknown IPI message 0x%x\n",
571 set_irq_regs(old_regs
);
574 void smp_send_reschedule(int cpu
)
576 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
579 void smp_send_stop(void)
581 unsigned long timeout
;
583 if (num_online_cpus() > 1) {
585 cpumask_copy(&mask
, cpu_online_mask
);
586 cpumask_clear_cpu(smp_processor_id(), &mask
);
588 smp_cross_call(&mask
, IPI_CPU_STOP
);
591 /* Wait up to one second for other CPUs to stop */
592 timeout
= USEC_PER_SEC
;
593 while (num_online_cpus() > 1 && timeout
--)
596 if (num_online_cpus() > 1)
597 pr_warning("SMP: failed to stop secondary CPUs\n");
603 int setup_profiling_timer(unsigned int multiplier
)