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
;
62 static DECLARE_COMPLETION(cpu_running
);
64 int __cpuinit
__cpu_up(unsigned int cpu
, struct task_struct
*idle
)
69 * We need to tell the secondary core where to find
70 * its stack and the page tables.
72 secondary_data
.stack
= task_stack_page(idle
) + THREAD_START_SP
;
73 secondary_data
.pgdir
= virt_to_phys(idmap_pgd
);
74 secondary_data
.swapper_pg_dir
= virt_to_phys(swapper_pg_dir
);
75 __cpuc_flush_dcache_area(&secondary_data
, sizeof(secondary_data
));
76 outer_clean_range(__pa(&secondary_data
), __pa(&secondary_data
+ 1));
79 * Now bring the CPU into our world.
81 ret
= boot_secondary(cpu
, idle
);
84 * CPU was successfully started, wait for it
85 * to come online or time out.
87 wait_for_completion_timeout(&cpu_running
,
88 msecs_to_jiffies(1000));
90 if (!cpu_online(cpu
)) {
91 pr_crit("CPU%u: failed to come online\n", cpu
);
95 pr_err("CPU%u: failed to boot: %d\n", cpu
, ret
);
98 secondary_data
.stack
= NULL
;
99 secondary_data
.pgdir
= 0;
104 #ifdef CONFIG_HOTPLUG_CPU
105 static void percpu_timer_stop(void);
108 * __cpu_disable runs on the processor to be shutdown.
110 int __cpu_disable(void)
112 unsigned int cpu
= smp_processor_id();
115 ret
= platform_cpu_disable(cpu
);
120 * Take this CPU offline. Once we clear this, we can't return,
121 * and we must not schedule until we're ready to give up the cpu.
123 set_cpu_online(cpu
, false);
126 * OK - migrate IRQs away from this CPU
131 * Stop the local timer for this CPU.
136 * Flush user cache and TLB mappings, and then remove this CPU
137 * from the vm mask set of all processes.
140 local_flush_tlb_all();
142 clear_tasks_mm_cpumask(cpu
);
147 static DECLARE_COMPLETION(cpu_died
);
150 * called on the thread which is asking for a CPU to be shutdown -
151 * waits until shutdown has completed, or it is timed out.
153 void __cpu_die(unsigned int cpu
)
155 if (!wait_for_completion_timeout(&cpu_died
, msecs_to_jiffies(5000))) {
156 pr_err("CPU%u: cpu didn't die\n", cpu
);
159 printk(KERN_NOTICE
"CPU%u: shutdown\n", cpu
);
161 if (!platform_cpu_kill(cpu
))
162 printk("CPU%u: unable to kill\n", cpu
);
166 * Called from the idle thread for the CPU which has been shutdown.
168 * Note that we disable IRQs here, but do not re-enable them
169 * before returning to the caller. This is also the behaviour
170 * of the other hotplug-cpu capable cores, so presumably coming
171 * out of idle fixes this.
173 void __ref
cpu_die(void)
175 unsigned int cpu
= smp_processor_id();
182 /* Tell __cpu_die() that this CPU is now safe to dispose of */
183 RCU_NONIDLE(complete(&cpu_died
));
186 * actual CPU shutdown procedure is at least platform (if not
189 platform_cpu_die(cpu
);
192 * Do not return to the idle loop - jump back to the secondary
193 * cpu initialisation. There's some initialisation which needs
194 * to be repeated to undo the effects of taking the CPU offline.
196 __asm__("mov sp, %0\n"
198 " b secondary_start_kernel"
200 : "r" (task_stack_page(current
) + THREAD_SIZE
- 8));
202 #endif /* CONFIG_HOTPLUG_CPU */
205 * Called by both boot and secondaries to move global data into
206 * per-processor storage.
208 static void __cpuinit
smp_store_cpu_info(unsigned int cpuid
)
210 struct cpuinfo_arm
*cpu_info
= &per_cpu(cpu_data
, cpuid
);
212 cpu_info
->loops_per_jiffy
= loops_per_jiffy
;
214 store_cpu_topology(cpuid
);
217 static void percpu_timer_setup(void);
220 * This is the secondary CPU boot entry. We're using this CPUs
221 * idle thread stack, but a set of temporary page tables.
223 asmlinkage
void __cpuinit
secondary_start_kernel(void)
225 struct mm_struct
*mm
= &init_mm
;
226 unsigned int cpu
= smp_processor_id();
229 * All kernel threads share the same mm context; grab a
230 * reference and switch to it.
232 atomic_inc(&mm
->mm_count
);
233 current
->active_mm
= mm
;
234 cpumask_set_cpu(cpu
, mm_cpumask(mm
));
235 cpu_switch_mm(mm
->pgd
, mm
);
236 enter_lazy_tlb(mm
, current
);
237 local_flush_tlb_all();
239 printk("CPU%u: Booted secondary processor\n", cpu
);
243 trace_hardirqs_off();
246 * Give the platform a chance to do its own initialisation.
248 platform_secondary_init(cpu
);
250 notify_cpu_starting(cpu
);
254 smp_store_cpu_info(cpu
);
257 * OK, now it's safe to let the boot CPU continue. Wait for
258 * the CPU migration code to notice that the CPU is online
259 * before we continue - which happens after __cpu_up returns.
261 set_cpu_online(cpu
, true);
262 complete(&cpu_running
);
265 * Setup the percpu timer for this CPU.
267 percpu_timer_setup();
273 * OK, it's off to the idle thread for us
278 void __init
smp_cpus_done(unsigned int max_cpus
)
281 unsigned long bogosum
= 0;
283 for_each_online_cpu(cpu
)
284 bogosum
+= per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
286 printk(KERN_INFO
"SMP: Total of %d processors activated "
287 "(%lu.%02lu BogoMIPS).\n",
289 bogosum
/ (500000/HZ
),
290 (bogosum
/ (5000/HZ
)) % 100);
293 void __init
smp_prepare_boot_cpu(void)
297 void __init
smp_prepare_cpus(unsigned int max_cpus
)
299 unsigned int ncores
= num_possible_cpus();
303 smp_store_cpu_info(smp_processor_id());
306 * are we trying to boot more cores than exist?
308 if (max_cpus
> ncores
)
310 if (ncores
> 1 && max_cpus
) {
312 * Enable the local timer or broadcast device for the
313 * boot CPU, but only if we have more than one CPU.
315 percpu_timer_setup();
318 * Initialise the present map, which describes the set of CPUs
319 * actually populated at the present time. A platform should
320 * re-initialize the map in platform_smp_prepare_cpus() if
321 * present != possible (e.g. physical hotplug).
323 init_cpu_present(cpu_possible_mask
);
326 * Initialise the SCU if there are more than one CPU
327 * and let them know where to start.
329 platform_smp_prepare_cpus(max_cpus
);
333 static void (*smp_cross_call
)(const struct cpumask
*, unsigned int);
335 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
340 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
342 smp_cross_call(mask
, IPI_CALL_FUNC
);
345 void arch_send_call_function_single_ipi(int cpu
)
347 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC_SINGLE
);
350 static const char *ipi_types
[NR_IPI
] = {
351 #define S(x,s) [x] = s
352 S(IPI_WAKEUP
, "CPU wakeup interrupts"),
353 S(IPI_TIMER
, "Timer broadcast interrupts"),
354 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
355 S(IPI_CALL_FUNC
, "Function call interrupts"),
356 S(IPI_CALL_FUNC_SINGLE
, "Single function call interrupts"),
357 S(IPI_CPU_STOP
, "CPU stop interrupts"),
360 void show_ipi_list(struct seq_file
*p
, int prec
)
364 for (i
= 0; i
< NR_IPI
; i
++) {
365 seq_printf(p
, "%*s%u: ", prec
- 1, "IPI", i
);
367 for_each_present_cpu(cpu
)
368 seq_printf(p
, "%10u ",
369 __get_irq_stat(cpu
, ipi_irqs
[i
]));
371 seq_printf(p
, " %s\n", ipi_types
[i
]);
375 u64
smp_irq_stat_cpu(unsigned int cpu
)
380 for (i
= 0; i
< NR_IPI
; i
++)
381 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
387 * Timer (local or broadcast) support
389 static DEFINE_PER_CPU(struct clock_event_device
, percpu_clockevent
);
391 static void ipi_timer(void)
393 struct clock_event_device
*evt
= &__get_cpu_var(percpu_clockevent
);
394 evt
->event_handler(evt
);
397 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
398 static void smp_timer_broadcast(const struct cpumask
*mask
)
400 smp_cross_call(mask
, IPI_TIMER
);
403 #define smp_timer_broadcast NULL
406 static void broadcast_timer_set_mode(enum clock_event_mode mode
,
407 struct clock_event_device
*evt
)
411 static void __cpuinit
broadcast_timer_setup(struct clock_event_device
*evt
)
413 evt
->name
= "dummy_timer";
414 evt
->features
= CLOCK_EVT_FEAT_ONESHOT
|
415 CLOCK_EVT_FEAT_PERIODIC
|
416 CLOCK_EVT_FEAT_DUMMY
;
419 evt
->set_mode
= broadcast_timer_set_mode
;
421 clockevents_register_device(evt
);
424 static struct local_timer_ops
*lt_ops
;
426 #ifdef CONFIG_LOCAL_TIMERS
427 int local_timer_register(struct local_timer_ops
*ops
)
429 if (!is_smp() || !setup_max_cpus
)
440 static void __cpuinit
percpu_timer_setup(void)
442 unsigned int cpu
= smp_processor_id();
443 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
445 evt
->cpumask
= cpumask_of(cpu
);
446 evt
->broadcast
= smp_timer_broadcast
;
448 if (!lt_ops
|| lt_ops
->setup(evt
))
449 broadcast_timer_setup(evt
);
452 #ifdef CONFIG_HOTPLUG_CPU
454 * The generic clock events code purposely does not stop the local timer
455 * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
458 static void percpu_timer_stop(void)
460 unsigned int cpu
= smp_processor_id();
461 struct clock_event_device
*evt
= &per_cpu(percpu_clockevent
, cpu
);
468 static DEFINE_RAW_SPINLOCK(stop_lock
);
471 * ipi_cpu_stop - handle IPI from smp_send_stop()
473 static void ipi_cpu_stop(unsigned int cpu
)
475 if (system_state
== SYSTEM_BOOTING
||
476 system_state
== SYSTEM_RUNNING
) {
477 raw_spin_lock(&stop_lock
);
478 printk(KERN_CRIT
"CPU%u: stopping\n", cpu
);
480 raw_spin_unlock(&stop_lock
);
483 set_cpu_online(cpu
, false);
493 * Main handler for inter-processor interrupts
495 asmlinkage
void __exception_irq_entry
do_IPI(int ipinr
, struct pt_regs
*regs
)
497 handle_IPI(ipinr
, regs
);
500 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
502 unsigned int cpu
= smp_processor_id();
503 struct pt_regs
*old_regs
= set_irq_regs(regs
);
506 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
524 generic_smp_call_function_interrupt();
528 case IPI_CALL_FUNC_SINGLE
:
530 generic_smp_call_function_single_interrupt();
541 printk(KERN_CRIT
"CPU%u: Unknown IPI message 0x%x\n",
545 set_irq_regs(old_regs
);
548 void smp_send_reschedule(int cpu
)
550 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
553 #ifdef CONFIG_HOTPLUG_CPU
554 static void smp_kill_cpus(cpumask_t
*mask
)
557 for_each_cpu(cpu
, mask
)
558 platform_cpu_kill(cpu
);
561 static void smp_kill_cpus(cpumask_t
*mask
) { }
564 void smp_send_stop(void)
566 unsigned long timeout
;
569 cpumask_copy(&mask
, cpu_online_mask
);
570 cpumask_clear_cpu(smp_processor_id(), &mask
);
571 if (!cpumask_empty(&mask
))
572 smp_cross_call(&mask
, IPI_CPU_STOP
);
574 /* Wait up to one second for other CPUs to stop */
575 timeout
= USEC_PER_SEC
;
576 while (num_online_cpus() > 1 && timeout
--)
579 if (num_online_cpus() > 1)
580 pr_warning("SMP: failed to stop secondary CPUs\n");
582 smp_kill_cpus(&mask
);
588 int setup_profiling_timer(unsigned int multiplier
)