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/smp_plat.h>
46 #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 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 static unsigned long get_arch_pgd(pgd_t
*pgd
)
83 phys_addr_t pgdir
= virt_to_phys(pgd
);
84 BUG_ON(pgdir
& ARCH_PGD_MASK
);
85 return pgdir
>> ARCH_PGD_SHIFT
;
88 int __cpu_up(unsigned int cpu
, struct task_struct
*idle
)
93 * We need to tell the secondary core where to find
94 * its stack and the page tables.
96 secondary_data
.stack
= task_stack_page(idle
) + THREAD_START_SP
;
98 secondary_data
.mpu_rgn_szr
= mpu_rgn_info
.rgns
[MPU_RAM_REGION
].drsr
;
102 secondary_data
.pgdir
= get_arch_pgd(idmap_pgd
);
103 secondary_data
.swapper_pg_dir
= get_arch_pgd(swapper_pg_dir
);
105 __cpuc_flush_dcache_area(&secondary_data
, sizeof(secondary_data
));
106 outer_clean_range(__pa(&secondary_data
), __pa(&secondary_data
+ 1));
109 * Now bring the CPU into our world.
111 ret
= boot_secondary(cpu
, idle
);
114 * CPU was successfully started, wait for it
115 * to come online or time out.
117 wait_for_completion_timeout(&cpu_running
,
118 msecs_to_jiffies(1000));
120 if (!cpu_online(cpu
)) {
121 pr_crit("CPU%u: failed to come online\n", cpu
);
125 pr_err("CPU%u: failed to boot: %d\n", cpu
, ret
);
129 memset(&secondary_data
, 0, sizeof(secondary_data
));
133 /* platform specific SMP operations */
134 void __init
smp_init_cpus(void)
136 if (smp_ops
.smp_init_cpus
)
137 smp_ops
.smp_init_cpus();
140 int 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 int platform_can_cpu_hotplug(void)
149 #ifdef CONFIG_HOTPLUG_CPU
150 if (smp_ops
.cpu_kill
)
157 #ifdef CONFIG_HOTPLUG_CPU
158 static int platform_cpu_kill(unsigned int cpu
)
160 if (smp_ops
.cpu_kill
)
161 return smp_ops
.cpu_kill(cpu
);
165 static int platform_cpu_disable(unsigned int cpu
)
167 if (smp_ops
.cpu_disable
)
168 return smp_ops
.cpu_disable(cpu
);
171 * By default, allow disabling all CPUs except the first one,
172 * since this is special on a lot of platforms, e.g. because
173 * of clock tick interrupts.
175 return cpu
== 0 ? -EPERM
: 0;
178 * __cpu_disable runs on the processor to be shutdown.
180 int __cpu_disable(void)
182 unsigned int cpu
= smp_processor_id();
185 ret
= platform_cpu_disable(cpu
);
190 * Take this CPU offline. Once we clear this, we can't return,
191 * and we must not schedule until we're ready to give up the cpu.
193 set_cpu_online(cpu
, false);
196 * OK - migrate IRQs away from this CPU
201 * Flush user cache and TLB mappings, and then remove this CPU
202 * from the vm mask set of all processes.
204 * Caches are flushed to the Level of Unification Inner Shareable
205 * to write-back dirty lines to unified caches shared by all CPUs.
208 local_flush_tlb_all();
210 clear_tasks_mm_cpumask(cpu
);
215 static DECLARE_COMPLETION(cpu_died
);
218 * called on the thread which is asking for a CPU to be shutdown -
219 * waits until shutdown has completed, or it is timed out.
221 void __cpu_die(unsigned int cpu
)
223 if (!wait_for_completion_timeout(&cpu_died
, msecs_to_jiffies(5000))) {
224 pr_err("CPU%u: cpu didn't die\n", cpu
);
227 printk(KERN_NOTICE
"CPU%u: shutdown\n", cpu
);
230 * platform_cpu_kill() is generally expected to do the powering off
231 * and/or cutting of clocks to the dying CPU. Optionally, this may
232 * be done by the CPU which is dying in preference to supporting
233 * this call, but that means there is _no_ synchronisation between
234 * the requesting CPU and the dying CPU actually losing power.
236 if (!platform_cpu_kill(cpu
))
237 printk("CPU%u: unable to kill\n", cpu
);
241 * Called from the idle thread for the CPU which has been shutdown.
243 * Note that we disable IRQs here, but do not re-enable them
244 * before returning to the caller. This is also the behaviour
245 * of the other hotplug-cpu capable cores, so presumably coming
246 * out of idle fixes this.
248 void __ref
cpu_die(void)
250 unsigned int cpu
= smp_processor_id();
257 * Flush the data out of the L1 cache for this CPU. This must be
258 * before the completion to ensure that data is safely written out
259 * before platform_cpu_kill() gets called - which may disable
260 * *this* CPU and power down its cache.
265 * Tell __cpu_die() that this CPU is now safe to dispose of. Once
266 * this returns, power and/or clocks can be removed at any point
267 * from this CPU and its cache by platform_cpu_kill().
272 * Ensure that the cache lines associated with that completion are
273 * written out. This covers the case where _this_ CPU is doing the
274 * powering down, to ensure that the completion is visible to the
275 * CPU waiting for this one.
280 * The actual CPU shutdown procedure is at least platform (if not
281 * CPU) specific. This may remove power, or it may simply spin.
283 * Platforms are generally expected *NOT* to return from this call,
284 * although there are some which do because they have no way to
285 * power down the CPU. These platforms are the _only_ reason we
286 * have a return path which uses the fragment of assembly below.
288 * The return path should not be used for platforms which can
292 smp_ops
.cpu_die(cpu
);
295 * Do not return to the idle loop - jump back to the secondary
296 * cpu initialisation. There's some initialisation which needs
297 * to be repeated to undo the effects of taking the CPU offline.
299 __asm__("mov sp, %0\n"
301 " b secondary_start_kernel"
303 : "r" (task_stack_page(current
) + THREAD_SIZE
- 8));
305 #endif /* CONFIG_HOTPLUG_CPU */
308 * Called by both boot and secondaries to move global data into
309 * per-processor storage.
311 static void smp_store_cpu_info(unsigned int cpuid
)
313 struct cpuinfo_arm
*cpu_info
= &per_cpu(cpu_data
, cpuid
);
315 cpu_info
->loops_per_jiffy
= loops_per_jiffy
;
316 cpu_info
->cpuid
= read_cpuid_id();
318 store_cpu_topology(cpuid
);
322 * This is the secondary CPU boot entry. We're using this CPUs
323 * idle thread stack, but a set of temporary page tables.
325 asmlinkage
void secondary_start_kernel(void)
327 struct mm_struct
*mm
= &init_mm
;
331 * The identity mapping is uncached (strongly ordered), so
332 * switch away from it before attempting any exclusive accesses.
334 cpu_switch_mm(mm
->pgd
, mm
);
335 local_flush_bp_all();
336 enter_lazy_tlb(mm
, current
);
337 local_flush_tlb_all();
340 * All kernel threads share the same mm context; grab a
341 * reference and switch to it.
343 cpu
= smp_processor_id();
344 atomic_inc(&mm
->mm_count
);
345 current
->active_mm
= mm
;
346 cpumask_set_cpu(cpu
, mm_cpumask(mm
));
350 printk("CPU%u: Booted secondary processor\n", cpu
);
353 trace_hardirqs_off();
356 * Give the platform a chance to do its own initialisation.
358 if (smp_ops
.smp_secondary_init
)
359 smp_ops
.smp_secondary_init(cpu
);
361 notify_cpu_starting(cpu
);
365 smp_store_cpu_info(cpu
);
368 * OK, now it's safe to let the boot CPU continue. Wait for
369 * the CPU migration code to notice that the CPU is online
370 * before we continue - which happens after __cpu_up returns.
372 set_cpu_online(cpu
, true);
373 complete(&cpu_running
);
379 * OK, it's off to the idle thread for us
381 cpu_startup_entry(CPUHP_ONLINE
);
384 void __init
smp_cpus_done(unsigned int max_cpus
)
386 printk(KERN_INFO
"SMP: Total of %d processors activated.\n",
392 void __init
smp_prepare_boot_cpu(void)
394 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
397 void __init
smp_prepare_cpus(unsigned int max_cpus
)
399 unsigned int ncores
= num_possible_cpus();
403 smp_store_cpu_info(smp_processor_id());
406 * are we trying to boot more cores than exist?
408 if (max_cpus
> ncores
)
410 if (ncores
> 1 && max_cpus
) {
412 * Initialise the present map, which describes the set of CPUs
413 * actually populated at the present time. A platform should
414 * re-initialize the map in the platforms smp_prepare_cpus()
415 * if present != possible (e.g. physical hotplug).
417 init_cpu_present(cpu_possible_mask
);
420 * Initialise the SCU if there are more than one CPU
421 * and let them know where to start.
423 if (smp_ops
.smp_prepare_cpus
)
424 smp_ops
.smp_prepare_cpus(max_cpus
);
428 static void (*smp_cross_call
)(const struct cpumask
*, unsigned int);
430 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
436 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
438 smp_cross_call(mask
, IPI_CALL_FUNC
);
441 void arch_send_wakeup_ipi_mask(const struct cpumask
*mask
)
443 smp_cross_call(mask
, IPI_WAKEUP
);
446 void arch_send_call_function_single_ipi(int cpu
)
448 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC_SINGLE
);
451 static const char *ipi_types
[NR_IPI
] = {
452 #define S(x,s) [x] = s
453 S(IPI_WAKEUP
, "CPU wakeup interrupts"),
454 S(IPI_TIMER
, "Timer broadcast interrupts"),
455 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
456 S(IPI_CALL_FUNC
, "Function call interrupts"),
457 S(IPI_CALL_FUNC_SINGLE
, "Single function call interrupts"),
458 S(IPI_CPU_STOP
, "CPU stop interrupts"),
461 void show_ipi_list(struct seq_file
*p
, int prec
)
465 for (i
= 0; i
< NR_IPI
; i
++) {
466 seq_printf(p
, "%*s%u: ", prec
- 1, "IPI", i
);
468 for_each_online_cpu(cpu
)
469 seq_printf(p
, "%10u ",
470 __get_irq_stat(cpu
, ipi_irqs
[i
]));
472 seq_printf(p
, " %s\n", ipi_types
[i
]);
476 u64
smp_irq_stat_cpu(unsigned int cpu
)
481 for (i
= 0; i
< NR_IPI
; i
++)
482 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
487 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
488 void tick_broadcast(const struct cpumask
*mask
)
490 smp_cross_call(mask
, IPI_TIMER
);
494 static DEFINE_RAW_SPINLOCK(stop_lock
);
497 * ipi_cpu_stop - handle IPI from smp_send_stop()
499 static void ipi_cpu_stop(unsigned int cpu
)
501 if (system_state
== SYSTEM_BOOTING
||
502 system_state
== SYSTEM_RUNNING
) {
503 raw_spin_lock(&stop_lock
);
504 printk(KERN_CRIT
"CPU%u: stopping\n", cpu
);
506 raw_spin_unlock(&stop_lock
);
509 set_cpu_online(cpu
, false);
519 * Main handler for inter-processor interrupts
521 asmlinkage
void __exception_irq_entry
do_IPI(int ipinr
, struct pt_regs
*regs
)
523 handle_IPI(ipinr
, regs
);
526 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
528 unsigned int cpu
= smp_processor_id();
529 struct pt_regs
*old_regs
= set_irq_regs(regs
);
532 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
538 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
541 tick_receive_broadcast();
552 generic_smp_call_function_interrupt();
556 case IPI_CALL_FUNC_SINGLE
:
558 generic_smp_call_function_single_interrupt();
569 printk(KERN_CRIT
"CPU%u: Unknown IPI message 0x%x\n",
573 set_irq_regs(old_regs
);
576 void smp_send_reschedule(int cpu
)
578 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
581 void smp_send_stop(void)
583 unsigned long timeout
;
586 cpumask_copy(&mask
, cpu_online_mask
);
587 cpumask_clear_cpu(smp_processor_id(), &mask
);
588 if (!cpumask_empty(&mask
))
589 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
)
608 #ifdef CONFIG_CPU_FREQ
610 static DEFINE_PER_CPU(unsigned long, l_p_j_ref
);
611 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq
);
612 static unsigned long global_l_p_j_ref
;
613 static unsigned long global_l_p_j_ref_freq
;
615 static int cpufreq_callback(struct notifier_block
*nb
,
616 unsigned long val
, void *data
)
618 struct cpufreq_freqs
*freq
= data
;
621 if (freq
->flags
& CPUFREQ_CONST_LOOPS
)
624 if (!per_cpu(l_p_j_ref
, cpu
)) {
625 per_cpu(l_p_j_ref
, cpu
) =
626 per_cpu(cpu_data
, cpu
).loops_per_jiffy
;
627 per_cpu(l_p_j_ref_freq
, cpu
) = freq
->old
;
628 if (!global_l_p_j_ref
) {
629 global_l_p_j_ref
= loops_per_jiffy
;
630 global_l_p_j_ref_freq
= freq
->old
;
634 if ((val
== CPUFREQ_PRECHANGE
&& freq
->old
< freq
->new) ||
635 (val
== CPUFREQ_POSTCHANGE
&& freq
->old
> freq
->new) ||
636 (val
== CPUFREQ_RESUMECHANGE
|| val
== CPUFREQ_SUSPENDCHANGE
)) {
637 loops_per_jiffy
= cpufreq_scale(global_l_p_j_ref
,
638 global_l_p_j_ref_freq
,
640 per_cpu(cpu_data
, cpu
).loops_per_jiffy
=
641 cpufreq_scale(per_cpu(l_p_j_ref
, cpu
),
642 per_cpu(l_p_j_ref_freq
, cpu
),
648 static struct notifier_block cpufreq_notifier
= {
649 .notifier_call
= cpufreq_callback
,
652 static int __init
register_cpufreq_notifier(void)
654 return cpufreq_register_notifier(&cpufreq_notifier
,
655 CPUFREQ_TRANSITION_NOTIFIER
);
657 core_initcall(register_cpufreq_notifier
);