1 /*
2 * linux/arch/arm/kernel/smp.c
3 *
4 * Copyright (C) 2002 ARM Limited, All Rights Reserved.
5 *
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.
9 */
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>
19 #include <linux/mm.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
26 #include <asm/atomic.h>
27 #include <asm/cacheflush.h>
28 #include <asm/cpu.h>
29 #include <asm/mmu_context.h>
30 #include <asm/pgtable.h>
31 #include <asm/pgalloc.h>
32 #include <asm/processor.h>
33 #include <asm/tlbflush.h>
34 #include <asm/ptrace.h>
35
36 /*
37 * as from 2.5, kernels no longer have an init_tasks structure
38 * so we need some other way of telling a new secondary core
39 * where to place its SVC stack
40 */
41 struct secondary_data secondary_data;
42
43 /*
44 * structures for inter-processor calls
45 * - A collection of single bit ipi messages.
46 */
47 struct ipi_data {
48 spinlock_t lock;
49 unsigned long ipi_count;
50 unsigned long bits;
51 };
52
53 static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
54 .lock = SPIN_LOCK_UNLOCKED,
55 };
56
57 enum ipi_msg_type {
58 IPI_TIMER,
59 IPI_RESCHEDULE,
60 IPI_CALL_FUNC,
61 IPI_CALL_FUNC_SINGLE,
62 IPI_CPU_STOP,
63 };
64
__cpu_up(unsigned int cpu)65 int __cpuinit __cpu_up(unsigned int cpu)
66 {
67 struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
68 struct task_struct *idle = ci->idle;
69 pgd_t *pgd;
70 pmd_t *pmd;
71 int ret;
72
73 /*
74 * Spawn a new process manually, if not already done.
75 * Grab a pointer to its task struct so we can mess with it
76 */
77 if (!idle) {
78 idle = fork_idle(cpu);
79 if (IS_ERR(idle)) {
80 printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
81 return PTR_ERR(idle);
82 }
83 ci->idle = idle;
84 }
85
86 /*
87 * Allocate initial page tables to allow the new CPU to
88 * enable the MMU safely. This essentially means a set
89 * of our "standard" page tables, with the addition of
90 * a 1:1 mapping for the physical address of the kernel.
91 */
92 pgd = pgd_alloc(&init_mm);
93 pmd = pmd_offset(pgd + pgd_index(PHYS_OFFSET), PHYS_OFFSET);
94 *pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) |
95 PMD_TYPE_SECT | PMD_SECT_AP_WRITE);
96
97 /*
98 * We need to tell the secondary core where to find
99 * its stack and the page tables.
100 */
101 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
102 secondary_data.pgdir = virt_to_phys(pgd);
103 wmb();
104
105 /*
106 * Now bring the CPU into our world.
107 */
108 ret = boot_secondary(cpu, idle);
109 if (ret == 0) {
110 unsigned long timeout;
111
112 /*
113 * CPU was successfully started, wait for it
114 * to come online or time out.
115 */
116 timeout = jiffies + HZ;
117 while (time_before(jiffies, timeout)) {
118 if (cpu_online(cpu))
119 break;
120
121 udelay(10);
122 barrier();
123 }
124
125 if (!cpu_online(cpu))
126 ret = -EIO;
127 }
128
129 secondary_data.stack = NULL;
130 secondary_data.pgdir = 0;
131
132 *pmd = __pmd(0);
133 pgd_free(&init_mm, pgd);
134
135 if (ret) {
136 printk(KERN_CRIT "CPU%u: processor failed to boot\n", cpu);
137
138 /*
139 * FIXME: We need to clean up the new idle thread. --rmk
140 */
141 }
142
143 return ret;
144 }
145
146 #ifdef CONFIG_HOTPLUG_CPU
147 /*
148 * __cpu_disable runs on the processor to be shutdown.
149 */
__cpu_disable(void)150 int __cpuexit __cpu_disable(void)
151 {
152 unsigned int cpu = smp_processor_id();
153 struct task_struct *p;
154 int ret;
155
156 ret = mach_cpu_disable(cpu);
157 if (ret)
158 return ret;
159
160 /*
161 * Take this CPU offline. Once we clear this, we can't return,
162 * and we must not schedule until we're ready to give up the cpu.
163 */
164 cpu_clear(cpu, cpu_online_map);
165
166 /*
167 * OK - migrate IRQs away from this CPU
168 */
169 migrate_irqs();
170
171 /*
172 * Stop the local timer for this CPU.
173 */
174 local_timer_stop();
175
176 /*
177 * Flush user cache and TLB mappings, and then remove this CPU
178 * from the vm mask set of all processes.
179 */
180 flush_cache_all();
181 local_flush_tlb_all();
182
183 read_lock(&tasklist_lock);
184 for_each_process(p) {
185 if (p->mm)
186 cpu_clear(cpu, p->mm->cpu_vm_mask);
187 }
188 read_unlock(&tasklist_lock);
189
190 return 0;
191 }
192
193 /*
194 * called on the thread which is asking for a CPU to be shutdown -
195 * waits until shutdown has completed, or it is timed out.
196 */
__cpu_die(unsigned int cpu)197 void __cpuexit __cpu_die(unsigned int cpu)
198 {
199 if (!platform_cpu_kill(cpu))
200 printk("CPU%u: unable to kill\n", cpu);
201 }
202
203 /*
204 * Called from the idle thread for the CPU which has been shutdown.
205 *
206 * Note that we disable IRQs here, but do not re-enable them
207 * before returning to the caller. This is also the behaviour
208 * of the other hotplug-cpu capable cores, so presumably coming
209 * out of idle fixes this.
210 */
cpu_die(void)211 void __cpuexit cpu_die(void)
212 {
213 unsigned int cpu = smp_processor_id();
214
215 local_irq_disable();
216 idle_task_exit();
217
218 /*
219 * actual CPU shutdown procedure is at least platform (if not
220 * CPU) specific
221 */
222 platform_cpu_die(cpu);
223
224 /*
225 * Do not return to the idle loop - jump back to the secondary
226 * cpu initialisation. There's some initialisation which needs
227 * to be repeated to undo the effects of taking the CPU offline.
228 */
229 __asm__("mov sp, %0\n"
230 " b secondary_start_kernel"
231 :
232 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
233 }
234 #endif /* CONFIG_HOTPLUG_CPU */
235
236 /*
237 * This is the secondary CPU boot entry. We're using this CPUs
238 * idle thread stack, but a set of temporary page tables.
239 */
secondary_start_kernel(void)240 asmlinkage void __cpuinit secondary_start_kernel(void)
241 {
242 struct mm_struct *mm = &init_mm;
243 unsigned int cpu = smp_processor_id();
244
245 printk("CPU%u: Booted secondary processor\n", cpu);
246
247 /*
248 * All kernel threads share the same mm context; grab a
249 * reference and switch to it.
250 */
251 atomic_inc(&mm->mm_users);
252 atomic_inc(&mm->mm_count);
253 current->active_mm = mm;
254 cpu_set(cpu, mm->cpu_vm_mask);
255 cpu_switch_mm(mm->pgd, mm);
256 enter_lazy_tlb(mm, current);
257 local_flush_tlb_all();
258
259 cpu_init();
260 preempt_disable();
261
262 /*
263 * Give the platform a chance to do its own initialisation.
264 */
265 platform_secondary_init(cpu);
266
267 /*
268 * Enable local interrupts.
269 */
270 notify_cpu_starting(cpu);
271 local_irq_enable();
272 local_fiq_enable();
273
274 /*
275 * Setup local timer for this CPU.
276 */
277 local_timer_setup();
278
279 calibrate_delay();
280
281 smp_store_cpu_info(cpu);
282
283 /*
284 * OK, now it's safe to let the boot CPU continue
285 */
286 cpu_set(cpu, cpu_online_map);
287
288 /*
289 * OK, it's off to the idle thread for us
290 */
291 cpu_idle();
292 }
293
294 /*
295 * Called by both boot and secondaries to move global data into
296 * per-processor storage.
297 */
smp_store_cpu_info(unsigned int cpuid)298 void __cpuinit smp_store_cpu_info(unsigned int cpuid)
299 {
300 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
301
302 cpu_info->loops_per_jiffy = loops_per_jiffy;
303 }
304
smp_cpus_done(unsigned int max_cpus)305 void __init smp_cpus_done(unsigned int max_cpus)
306 {
307 int cpu;
308 unsigned long bogosum = 0;
309
310 for_each_online_cpu(cpu)
311 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
312
313 printk(KERN_INFO "SMP: Total of %d processors activated "
314 "(%lu.%02lu BogoMIPS).\n",
315 num_online_cpus(),
316 bogosum / (500000/HZ),
317 (bogosum / (5000/HZ)) % 100);
318 }
319
smp_prepare_boot_cpu(void)320 void __init smp_prepare_boot_cpu(void)
321 {
322 unsigned int cpu = smp_processor_id();
323
324 per_cpu(cpu_data, cpu).idle = current;
325 }
326
send_ipi_message(cpumask_t callmap,enum ipi_msg_type msg)327 static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg)
328 {
329 unsigned long flags;
330 unsigned int cpu;
331
332 local_irq_save(flags);
333
334 for_each_cpu_mask(cpu, callmap) {
335 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
336
337 spin_lock(&ipi->lock);
338 ipi->bits |= 1 << msg;
339 spin_unlock(&ipi->lock);
340 }
341
342 /*
343 * Call the platform specific cross-CPU call function.
344 */
345 smp_cross_call(callmap);
346
347 local_irq_restore(flags);
348 }
349
arch_send_call_function_ipi(cpumask_t mask)350 void arch_send_call_function_ipi(cpumask_t mask)
351 {
352 send_ipi_message(mask, IPI_CALL_FUNC);
353 }
354
arch_send_call_function_single_ipi(int cpu)355 void arch_send_call_function_single_ipi(int cpu)
356 {
357 send_ipi_message(cpumask_of_cpu(cpu), IPI_CALL_FUNC_SINGLE);
358 }
359
show_ipi_list(struct seq_file * p)360 void show_ipi_list(struct seq_file *p)
361 {
362 unsigned int cpu;
363
364 seq_puts(p, "IPI:");
365
366 for_each_present_cpu(cpu)
367 seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
368
369 seq_putc(p, '\n');
370 }
371
show_local_irqs(struct seq_file * p)372 void show_local_irqs(struct seq_file *p)
373 {
374 unsigned int cpu;
375
376 seq_printf(p, "LOC: ");
377
378 for_each_present_cpu(cpu)
379 seq_printf(p, "%10u ", irq_stat[cpu].local_timer_irqs);
380
381 seq_putc(p, '\n');
382 }
383
ipi_timer(void)384 static void ipi_timer(void)
385 {
386 irq_enter();
387 local_timer_interrupt();
388 irq_exit();
389 }
390
391 #ifdef CONFIG_LOCAL_TIMERS
do_local_timer(struct pt_regs * regs)392 asmlinkage void __exception do_local_timer(struct pt_regs *regs)
393 {
394 struct pt_regs *old_regs = set_irq_regs(regs);
395 int cpu = smp_processor_id();
396
397 if (local_timer_ack()) {
398 irq_stat[cpu].local_timer_irqs++;
399 ipi_timer();
400 }
401
402 set_irq_regs(old_regs);
403 }
404 #endif
405
406 static DEFINE_SPINLOCK(stop_lock);
407
408 /*
409 * ipi_cpu_stop - handle IPI from smp_send_stop()
410 */
ipi_cpu_stop(unsigned int cpu)411 static void ipi_cpu_stop(unsigned int cpu)
412 {
413 spin_lock(&stop_lock);
414 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
415 dump_stack();
416 spin_unlock(&stop_lock);
417
418 cpu_clear(cpu, cpu_online_map);
419
420 local_fiq_disable();
421 local_irq_disable();
422
423 while (1)
424 cpu_relax();
425 }
426
427 /*
428 * Main handler for inter-processor interrupts
429 *
430 * For ARM, the ipimask now only identifies a single
431 * category of IPI (Bit 1 IPIs have been replaced by a
432 * different mechanism):
433 *
434 * Bit 0 - Inter-processor function call
435 */
do_IPI(struct pt_regs * regs)436 asmlinkage void __exception do_IPI(struct pt_regs *regs)
437 {
438 unsigned int cpu = smp_processor_id();
439 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
440 struct pt_regs *old_regs = set_irq_regs(regs);
441
442 ipi->ipi_count++;
443
444 for (;;) {
445 unsigned long msgs;
446
447 spin_lock(&ipi->lock);
448 msgs = ipi->bits;
449 ipi->bits = 0;
450 spin_unlock(&ipi->lock);
451
452 if (!msgs)
453 break;
454
455 do {
456 unsigned nextmsg;
457
458 nextmsg = msgs & -msgs;
459 msgs &= ~nextmsg;
460 nextmsg = ffz(~nextmsg);
461
462 switch (nextmsg) {
463 case IPI_TIMER:
464 ipi_timer();
465 break;
466
467 case IPI_RESCHEDULE:
468 /*
469 * nothing more to do - eveything is
470 * done on the interrupt return path
471 */
472 break;
473
474 case IPI_CALL_FUNC:
475 generic_smp_call_function_interrupt();
476 break;
477
478 case IPI_CALL_FUNC_SINGLE:
479 generic_smp_call_function_single_interrupt();
480 break;
481
482 case IPI_CPU_STOP:
483 ipi_cpu_stop(cpu);
484 break;
485
486 default:
487 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
488 cpu, nextmsg);
489 break;
490 }
491 } while (msgs);
492 }
493
494 set_irq_regs(old_regs);
495 }
496
smp_send_reschedule(int cpu)497 void smp_send_reschedule(int cpu)
498 {
499 send_ipi_message(cpumask_of_cpu(cpu), IPI_RESCHEDULE);
500 }
501
smp_send_timer(void)502 void smp_send_timer(void)
503 {
504 cpumask_t mask = cpu_online_map;
505 cpu_clear(smp_processor_id(), mask);
506 send_ipi_message(mask, IPI_TIMER);
507 }
508
smp_timer_broadcast(cpumask_t mask)509 void smp_timer_broadcast(cpumask_t mask)
510 {
511 send_ipi_message(mask, IPI_TIMER);
512 }
513
smp_send_stop(void)514 void smp_send_stop(void)
515 {
516 cpumask_t mask = cpu_online_map;
517 cpu_clear(smp_processor_id(), mask);
518 send_ipi_message(mask, IPI_CPU_STOP);
519 }
520
521 /*
522 * not supported here
523 */
setup_profiling_timer(unsigned int multiplier)524 int setup_profiling_timer(unsigned int multiplier)
525 {
526 return -EINVAL;
527 }
528
529 static int
on_each_cpu_mask(void (* func)(void *),void * info,int wait,cpumask_t mask)530 on_each_cpu_mask(void (*func)(void *), void *info, int wait, cpumask_t mask)
531 {
532 int ret = 0;
533
534 preempt_disable();
535
536 ret = smp_call_function_mask(mask, func, info, wait);
537 if (cpu_isset(smp_processor_id(), mask))
538 func(info);
539
540 preempt_enable();
541
542 return ret;
543 }
544
545 /**********************************************************************/
546
547 /*
548 * TLB operations
549 */
550 struct tlb_args {
551 struct vm_area_struct *ta_vma;
552 unsigned long ta_start;
553 unsigned long ta_end;
554 };
555
ipi_flush_tlb_all(void * ignored)556 static inline void ipi_flush_tlb_all(void *ignored)
557 {
558 local_flush_tlb_all();
559 }
560
ipi_flush_tlb_mm(void * arg)561 static inline void ipi_flush_tlb_mm(void *arg)
562 {
563 struct mm_struct *mm = (struct mm_struct *)arg;
564
565 local_flush_tlb_mm(mm);
566 }
567
ipi_flush_tlb_page(void * arg)568 static inline void ipi_flush_tlb_page(void *arg)
569 {
570 struct tlb_args *ta = (struct tlb_args *)arg;
571
572 local_flush_tlb_page(ta->ta_vma, ta->ta_start);
573 }
574
ipi_flush_tlb_kernel_page(void * arg)575 static inline void ipi_flush_tlb_kernel_page(void *arg)
576 {
577 struct tlb_args *ta = (struct tlb_args *)arg;
578
579 local_flush_tlb_kernel_page(ta->ta_start);
580 }
581
ipi_flush_tlb_range(void * arg)582 static inline void ipi_flush_tlb_range(void *arg)
583 {
584 struct tlb_args *ta = (struct tlb_args *)arg;
585
586 local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
587 }
588
ipi_flush_tlb_kernel_range(void * arg)589 static inline void ipi_flush_tlb_kernel_range(void *arg)
590 {
591 struct tlb_args *ta = (struct tlb_args *)arg;
592
593 local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end);
594 }
595
flush_tlb_all(void)596 void flush_tlb_all(void)
597 {
598 on_each_cpu(ipi_flush_tlb_all, NULL, 1);
599 }
600
flush_tlb_mm(struct mm_struct * mm)601 void flush_tlb_mm(struct mm_struct *mm)
602 {
603 cpumask_t mask = mm->cpu_vm_mask;
604
605 on_each_cpu_mask(ipi_flush_tlb_mm, mm, 1, mask);
606 }
607
flush_tlb_page(struct vm_area_struct * vma,unsigned long uaddr)608 void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
609 {
610 cpumask_t mask = vma->vm_mm->cpu_vm_mask;
611 struct tlb_args ta;
612
613 ta.ta_vma = vma;
614 ta.ta_start = uaddr;
615
616 on_each_cpu_mask(ipi_flush_tlb_page, &ta, 1, mask);
617 }
618
flush_tlb_kernel_page(unsigned long kaddr)619 void flush_tlb_kernel_page(unsigned long kaddr)
620 {
621 struct tlb_args ta;
622
623 ta.ta_start = kaddr;
624
625 on_each_cpu(ipi_flush_tlb_kernel_page, &ta, 1);
626 }
627
flush_tlb_range(struct vm_area_struct * vma,unsigned long start,unsigned long end)628 void flush_tlb_range(struct vm_area_struct *vma,
629 unsigned long start, unsigned long end)
630 {
631 cpumask_t mask = vma->vm_mm->cpu_vm_mask;
632 struct tlb_args ta;
633
634 ta.ta_vma = vma;
635 ta.ta_start = start;
636 ta.ta_end = end;
637
638 on_each_cpu_mask(ipi_flush_tlb_range, &ta, 1, mask);
639 }
640
flush_tlb_kernel_range(unsigned long start,unsigned long end)641 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
642 {
643 struct tlb_args ta;
644
645 ta.ta_start = start;
646 ta.ta_end = end;
647
648 on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1);
649 }
650