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1 /*
2 ** SMP Support
3 **
4 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
5 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
6 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
7 **
8 ** Lots of stuff stolen from arch/alpha/kernel/smp.c
9 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
10 **
11 ** Thanks to John Curry and Ullas Ponnadi. I learned alot from their work.
12 ** -grant (1/12/2001)
13 **
14 ** This program is free software; you can redistribute it and/or modify
15 ** it under the terms of the GNU General Public License as published by
16 ** the Free Software Foundation; either version 2 of the License, or
17 ** (at your option) any later version.
18 */
19 #undef ENTRY_SYS_CPUS /* syscall support for iCOD-like functionality */
20
21 #include <linux/config.h>
22
23 #include <linux/types.h>
24 #include <linux/spinlock.h>
25 #include <linux/slab.h>
26
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/sched.h>
30 #include <linux/init.h>
31 #include <linux/interrupt.h>
32 #include <linux/smp.h>
33 #include <linux/kernel_stat.h>
34 #include <linux/mm.h>
35 #include <linux/delay.h>
36 #include <linux/bitops.h>
37
38 #include <asm/system.h>
39 #include <asm/atomic.h>
40 #include <asm/current.h>
41 #include <asm/delay.h>
42 #include <asm/tlbflush.h>
43
44 #include <asm/io.h>
45 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
46 #include <asm/mmu_context.h>
47 #include <asm/page.h>
48 #include <asm/pgtable.h>
49 #include <asm/pgalloc.h>
50 #include <asm/processor.h>
51 #include <asm/ptrace.h>
52 #include <asm/unistd.h>
53 #include <asm/cacheflush.h>
54
55 #define kDEBUG 0
56
57 DEFINE_SPINLOCK(smp_lock);
58
59 volatile struct task_struct *smp_init_current_idle_task;
60
61 static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */
62
63 static int parisc_max_cpus __read_mostly = 1;
64
65 /* online cpus are ones that we've managed to bring up completely
66 * possible cpus are all valid cpu
67 * present cpus are all detected cpu
68 *
69 * On startup we bring up the "possible" cpus. Since we discover
70 * CPUs later, we add them as hotplug, so the possible cpu mask is
71 * empty in the beginning.
72 */
73
74 cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */
75 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */
76
77 EXPORT_SYMBOL(cpu_online_map);
78 EXPORT_SYMBOL(cpu_possible_map);
79
80
81 struct smp_call_struct {
82 void (*func) (void *info);
83 void *info;
84 long wait;
85 atomic_t unstarted_count;
86 atomic_t unfinished_count;
87 };
88 static volatile struct smp_call_struct *smp_call_function_data;
89
90 enum ipi_message_type {
91 IPI_NOP=0,
92 IPI_RESCHEDULE=1,
93 IPI_CALL_FUNC,
94 IPI_CPU_START,
95 IPI_CPU_STOP,
96 IPI_CPU_TEST
97 };
98
99
100 /********** SMP inter processor interrupt and communication routines */
101
102 #undef PER_CPU_IRQ_REGION
103 #ifdef PER_CPU_IRQ_REGION
104 /* XXX REVISIT Ignore for now.
105 ** *May* need this "hook" to register IPI handler
106 ** once we have perCPU ExtIntr switch tables.
107 */
108 static void
109 ipi_init(int cpuid)
110 {
111
112 /* If CPU is present ... */
113 #ifdef ENTRY_SYS_CPUS
114 /* *and* running (not stopped) ... */
115 #error iCOD support wants state checked here.
116 #endif
117
118 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
119
120 if(cpu_online(cpuid) )
121 {
122 switch_to_idle_task(current);
123 }
124
125 return;
126 }
127 #endif
128
129
130 /*
131 ** Yoink this CPU from the runnable list...
132 **
133 */
134 static void
135 halt_processor(void)
136 {
137 #ifdef ENTRY_SYS_CPUS
138 #error halt_processor() needs rework
139 /*
140 ** o migrate I/O interrupts off this CPU.
141 ** o leave IPI enabled - __cli() will disable IPI.
142 ** o leave CPU in online map - just change the state
143 */
144 cpu_data[this_cpu].state = STATE_STOPPED;
145 mark_bh(IPI_BH);
146 #else
147 /* REVISIT : redirect I/O Interrupts to another CPU? */
148 /* REVISIT : does PM *know* this CPU isn't available? */
149 cpu_clear(smp_processor_id(), cpu_online_map);
150 local_irq_disable();
151 for (;;)
152 ;
153 #endif
154 }
155
156
157 irqreturn_t
158 ipi_interrupt(int irq, void *dev_id, struct pt_regs *regs)
159 {
160 int this_cpu = smp_processor_id();
161 struct cpuinfo_parisc *p = &cpu_data[this_cpu];
162 unsigned long ops;
163 unsigned long flags;
164
165 /* Count this now; we may make a call that never returns. */
166 p->ipi_count++;
167
168 mb(); /* Order interrupt and bit testing. */
169
170 for (;;) {
171 spin_lock_irqsave(&(p->lock),flags);
172 ops = p->pending_ipi;
173 p->pending_ipi = 0;
174 spin_unlock_irqrestore(&(p->lock),flags);
175
176 mb(); /* Order bit clearing and data access. */
177
178 if (!ops)
179 break;
180
181 while (ops) {
182 unsigned long which = ffz(~ops);
183
184 ops &= ~(1 << which);
185
186 switch (which) {
187 case IPI_NOP:
188 #if (kDEBUG>=100)
189 printk(KERN_DEBUG "CPU%d IPI_NOP\n",this_cpu);
190 #endif /* kDEBUG */
191 break;
192
193 case IPI_RESCHEDULE:
194 #if (kDEBUG>=100)
195 printk(KERN_DEBUG "CPU%d IPI_RESCHEDULE\n",this_cpu);
196 #endif /* kDEBUG */
197 /*
198 * Reschedule callback. Everything to be
199 * done is done by the interrupt return path.
200 */
201 break;
202
203 case IPI_CALL_FUNC:
204 #if (kDEBUG>=100)
205 printk(KERN_DEBUG "CPU%d IPI_CALL_FUNC\n",this_cpu);
206 #endif /* kDEBUG */
207 {
208 volatile struct smp_call_struct *data;
209 void (*func)(void *info);
210 void *info;
211 int wait;
212
213 data = smp_call_function_data;
214 func = data->func;
215 info = data->info;
216 wait = data->wait;
217
218 mb();
219 atomic_dec ((atomic_t *)&data->unstarted_count);
220
221 /* At this point, *data can't
222 * be relied upon.
223 */
224
225 (*func)(info);
226
227 /* Notify the sending CPU that the
228 * task is done.
229 */
230 mb();
231 if (wait)
232 atomic_dec ((atomic_t *)&data->unfinished_count);
233 }
234 break;
235
236 case IPI_CPU_START:
237 #if (kDEBUG>=100)
238 printk(KERN_DEBUG "CPU%d IPI_CPU_START\n",this_cpu);
239 #endif /* kDEBUG */
240 #ifdef ENTRY_SYS_CPUS
241 p->state = STATE_RUNNING;
242 #endif
243 break;
244
245 case IPI_CPU_STOP:
246 #if (kDEBUG>=100)
247 printk(KERN_DEBUG "CPU%d IPI_CPU_STOP\n",this_cpu);
248 #endif /* kDEBUG */
249 #ifdef ENTRY_SYS_CPUS
250 #else
251 halt_processor();
252 #endif
253 break;
254
255 case IPI_CPU_TEST:
256 #if (kDEBUG>=100)
257 printk(KERN_DEBUG "CPU%d is alive!\n",this_cpu);
258 #endif /* kDEBUG */
259 break;
260
261 default:
262 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
263 this_cpu, which);
264 return IRQ_NONE;
265 } /* Switch */
266 } /* while (ops) */
267 }
268 return IRQ_HANDLED;
269 }
270
271
272 static inline void
273 ipi_send(int cpu, enum ipi_message_type op)
274 {
275 struct cpuinfo_parisc *p = &cpu_data[cpu];
276 unsigned long flags;
277
278 spin_lock_irqsave(&(p->lock),flags);
279 p->pending_ipi |= 1 << op;
280 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa);
281 spin_unlock_irqrestore(&(p->lock),flags);
282 }
283
284
285 static inline void
286 send_IPI_single(int dest_cpu, enum ipi_message_type op)
287 {
288 if (dest_cpu == NO_PROC_ID) {
289 BUG();
290 return;
291 }
292
293 ipi_send(dest_cpu, op);
294 }
295
296 static inline void
297 send_IPI_allbutself(enum ipi_message_type op)
298 {
299 int i;
300
301 for (i = 0; i < NR_CPUS; i++) {
302 if (cpu_online(i) && i != smp_processor_id())
303 send_IPI_single(i, op);
304 }
305 }
306
307
308 inline void
309 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
310
311 static inline void
312 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); }
313
314 void
315 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
316
317 void
318 smp_send_all_nop(void)
319 {
320 send_IPI_allbutself(IPI_NOP);
321 }
322
323
324 /**
325 * Run a function on all other CPUs.
326 * <func> The function to run. This must be fast and non-blocking.
327 * <info> An arbitrary pointer to pass to the function.
328 * <retry> If true, keep retrying until ready.
329 * <wait> If true, wait until function has completed on other CPUs.
330 * [RETURNS] 0 on success, else a negative status code.
331 *
332 * Does not return until remote CPUs are nearly ready to execute <func>
333 * or have executed.
334 */
335
336 int
337 smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
338 {
339 struct smp_call_struct data;
340 unsigned long timeout;
341 static DEFINE_SPINLOCK(lock);
342 int retries = 0;
343
344 if (num_online_cpus() < 2)
345 return 0;
346
347 /* Can deadlock when called with interrupts disabled */
348 WARN_ON(irqs_disabled());
349
350 /* can also deadlock if IPIs are disabled */
351 WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0);
352
353
354 data.func = func;
355 data.info = info;
356 data.wait = wait;
357 atomic_set(&data.unstarted_count, num_online_cpus() - 1);
358 atomic_set(&data.unfinished_count, num_online_cpus() - 1);
359
360 if (retry) {
361 spin_lock (&lock);
362 while (smp_call_function_data != 0)
363 barrier();
364 }
365 else {
366 spin_lock (&lock);
367 if (smp_call_function_data) {
368 spin_unlock (&lock);
369 return -EBUSY;
370 }
371 }
372
373 smp_call_function_data = &data;
374 spin_unlock (&lock);
375
376 /* Send a message to all other CPUs and wait for them to respond */
377 send_IPI_allbutself(IPI_CALL_FUNC);
378
379 retry:
380 /* Wait for response */
381 timeout = jiffies + HZ;
382 while ( (atomic_read (&data.unstarted_count) > 0) &&
383 time_before (jiffies, timeout) )
384 barrier ();
385
386 if (atomic_read (&data.unstarted_count) > 0) {
387 printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n",
388 smp_processor_id(), ++retries);
389 goto retry;
390 }
391 /* We either got one or timed out. Release the lock */
392
393 mb();
394 smp_call_function_data = NULL;
395
396 while (wait && atomic_read (&data.unfinished_count) > 0)
397 barrier ();
398
399 return 0;
400 }
401
402 EXPORT_SYMBOL(smp_call_function);
403
404 /*
405 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu()
406 * as we want to ensure all TLB's flushed before proceeding.
407 */
408
409 void
410 smp_flush_tlb_all(void)
411 {
412 on_each_cpu(flush_tlb_all_local, NULL, 1, 1);
413 }
414
415
416 void
417 smp_do_timer(struct pt_regs *regs)
418 {
419 int cpu = smp_processor_id();
420 struct cpuinfo_parisc *data = &cpu_data[cpu];
421
422 if (!--data->prof_counter) {
423 data->prof_counter = data->prof_multiplier;
424 update_process_times(user_mode(regs));
425 }
426 }
427
428 /*
429 * Called by secondaries to update state and initialize CPU registers.
430 */
431 static void __init
432 smp_cpu_init(int cpunum)
433 {
434 extern int init_per_cpu(int); /* arch/parisc/kernel/setup.c */
435 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
436
437 /* Set modes and Enable floating point coprocessor */
438 (void) init_per_cpu(cpunum);
439
440 disable_sr_hashing();
441
442 mb();
443
444 /* Well, support 2.4 linux scheme as well. */
445 if (cpu_test_and_set(cpunum, cpu_online_map))
446 {
447 extern void machine_halt(void); /* arch/parisc.../process.c */
448
449 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
450 machine_halt();
451 }
452
453 /* Initialise the idle task for this CPU */
454 atomic_inc(&init_mm.mm_count);
455 current->active_mm = &init_mm;
456 if(current->mm)
457 BUG();
458 enter_lazy_tlb(&init_mm, current);
459
460 init_IRQ(); /* make sure no IRQ's are enabled or pending */
461 }
462
463
464 /*
465 * Slaves start using C here. Indirectly called from smp_slave_stext.
466 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
467 */
468 void __init smp_callin(void)
469 {
470 int slave_id = cpu_now_booting;
471 #if 0
472 void *istack;
473 #endif
474
475 smp_cpu_init(slave_id);
476 preempt_disable();
477
478 #if 0 /* NOT WORKING YET - see entry.S */
479 istack = (void *)__get_free_pages(GFP_KERNEL,ISTACK_ORDER);
480 if (istack == NULL) {
481 printk(KERN_CRIT "Failed to allocate interrupt stack for cpu %d\n",slave_id);
482 BUG();
483 }
484 mtctl(istack,31);
485 #endif
486
487 flush_cache_all_local(); /* start with known state */
488 flush_tlb_all_local(NULL);
489
490 local_irq_enable(); /* Interrupts have been off until now */
491
492 cpu_idle(); /* Wait for timer to schedule some work */
493
494 /* NOTREACHED */
495 panic("smp_callin() AAAAaaaaahhhh....\n");
496 }
497
498 /*
499 * Bring one cpu online.
500 */
501 int __init smp_boot_one_cpu(int cpuid)
502 {
503 struct task_struct *idle;
504 long timeout;
505
506 /*
507 * Create an idle task for this CPU. Note the address wed* give
508 * to kernel_thread is irrelevant -- it's going to start
509 * where OS_BOOT_RENDEVZ vector in SAL says to start. But
510 * this gets all the other task-y sort of data structures set
511 * up like we wish. We need to pull the just created idle task
512 * off the run queue and stuff it into the init_tasks[] array.
513 * Sheesh . . .
514 */
515
516 idle = fork_idle(cpuid);
517 if (IS_ERR(idle))
518 panic("SMP: fork failed for CPU:%d", cpuid);
519
520 idle->thread_info->cpu = cpuid;
521
522 /* Let _start know what logical CPU we're booting
523 ** (offset into init_tasks[],cpu_data[])
524 */
525 cpu_now_booting = cpuid;
526
527 /*
528 ** boot strap code needs to know the task address since
529 ** it also contains the process stack.
530 */
531 smp_init_current_idle_task = idle ;
532 mb();
533
534 printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa);
535
536 /*
537 ** This gets PDC to release the CPU from a very tight loop.
538 **
539 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
540 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
541 ** is executed after receiving the rendezvous signal (an interrupt to
542 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
543 ** contents of memory are valid."
544 */
545 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa);
546 mb();
547
548 /*
549 * OK, wait a bit for that CPU to finish staggering about.
550 * Slave will set a bit when it reaches smp_cpu_init().
551 * Once the "monarch CPU" sees the bit change, it can move on.
552 */
553 for (timeout = 0; timeout < 10000; timeout++) {
554 if(cpu_online(cpuid)) {
555 /* Which implies Slave has started up */
556 cpu_now_booting = 0;
557 smp_init_current_idle_task = NULL;
558 goto alive ;
559 }
560 udelay(100);
561 barrier();
562 }
563
564 put_task_struct(idle);
565 idle = NULL;
566
567 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
568 return -1;
569
570 alive:
571 /* Remember the Slave data */
572 #if (kDEBUG>=100)
573 printk(KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
574 cpuid, timeout * 100);
575 #endif /* kDEBUG */
576 #ifdef ENTRY_SYS_CPUS
577 cpu_data[cpuid].state = STATE_RUNNING;
578 #endif
579 return 0;
580 }
581
582 void __devinit smp_prepare_boot_cpu(void)
583 {
584 int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */
585
586 #ifdef ENTRY_SYS_CPUS
587 cpu_data[0].state = STATE_RUNNING;
588 #endif
589
590 /* Setup BSP mappings */
591 printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor);
592
593 cpu_set(bootstrap_processor, cpu_online_map);
594 cpu_set(bootstrap_processor, cpu_present_map);
595 }
596
597
598
599 /*
600 ** inventory.c:do_inventory() hasn't yet been run and thus we
601 ** don't 'discover' the additional CPU's until later.
602 */
603 void __init smp_prepare_cpus(unsigned int max_cpus)
604 {
605 cpus_clear(cpu_present_map);
606 cpu_set(0, cpu_present_map);
607
608 parisc_max_cpus = max_cpus;
609 if (!max_cpus)
610 printk(KERN_INFO "SMP mode deactivated.\n");
611 }
612
613
614 void smp_cpus_done(unsigned int cpu_max)
615 {
616 return;
617 }
618
619
620 int __devinit __cpu_up(unsigned int cpu)
621 {
622 if (cpu != 0 && cpu < parisc_max_cpus)
623 smp_boot_one_cpu(cpu);
624
625 return cpu_online(cpu) ? 0 : -ENOSYS;
626 }
627
628
629
630 #ifdef ENTRY_SYS_CPUS
631 /* Code goes along with:
632 ** entry.s: ENTRY_NAME(sys_cpus) / * 215, for cpu stat * /
633 */
634 int sys_cpus(int argc, char **argv)
635 {
636 int i,j=0;
637 extern int current_pid(int cpu);
638
639 if( argc > 2 ) {
640 printk("sys_cpus:Only one argument supported\n");
641 return (-1);
642 }
643 if ( argc == 1 ){
644
645 #ifdef DUMP_MORE_STATE
646 for(i=0; i<NR_CPUS; i++) {
647 int cpus_per_line = 4;
648 if(cpu_online(i)) {
649 if (j++ % cpus_per_line)
650 printk(" %3d",i);
651 else
652 printk("\n %3d",i);
653 }
654 }
655 printk("\n");
656 #else
657 printk("\n 0\n");
658 #endif
659 } else if((argc==2) && !(strcmp(argv[1],"-l"))) {
660 printk("\nCPUSTATE TASK CPUNUM CPUID HARDCPU(HPA)\n");
661 #ifdef DUMP_MORE_STATE
662 for(i=0;i<NR_CPUS;i++) {
663 if (!cpu_online(i))
664 continue;
665 if (cpu_data[i].cpuid != NO_PROC_ID) {
666 switch(cpu_data[i].state) {
667 case STATE_RENDEZVOUS:
668 printk("RENDEZVS ");
669 break;
670 case STATE_RUNNING:
671 printk((current_pid(i)!=0) ? "RUNNING " : "IDLING ");
672 break;
673 case STATE_STOPPED:
674 printk("STOPPED ");
675 break;
676 case STATE_HALTED:
677 printk("HALTED ");
678 break;
679 default:
680 printk("%08x?", cpu_data[i].state);
681 break;
682 }
683 if(cpu_online(i)) {
684 printk(" %4d",current_pid(i));
685 }
686 printk(" %6d",cpu_number_map(i));
687 printk(" %5d",i);
688 printk(" 0x%lx\n",cpu_data[i].hpa);
689 }
690 }
691 #else
692 printk("\n%s %4d 0 0 --------",
693 (current->pid)?"RUNNING ": "IDLING ",current->pid);
694 #endif
695 } else if ((argc==2) && !(strcmp(argv[1],"-s"))) {
696 #ifdef DUMP_MORE_STATE
697 printk("\nCPUSTATE CPUID\n");
698 for (i=0;i<NR_CPUS;i++) {
699 if (!cpu_online(i))
700 continue;
701 if (cpu_data[i].cpuid != NO_PROC_ID) {
702 switch(cpu_data[i].state) {
703 case STATE_RENDEZVOUS:
704 printk("RENDEZVS");break;
705 case STATE_RUNNING:
706 printk((current_pid(i)!=0) ? "RUNNING " : "IDLING");
707 break;
708 case STATE_STOPPED:
709 printk("STOPPED ");break;
710 case STATE_HALTED:
711 printk("HALTED ");break;
712 default:
713 }
714 printk(" %5d\n",i);
715 }
716 }
717 #else
718 printk("\n%s CPU0",(current->pid==0)?"RUNNING ":"IDLING ");
719 #endif
720 } else {
721 printk("sys_cpus:Unknown request\n");
722 return (-1);
723 }
724 return 0;
725 }
726 #endif /* ENTRY_SYS_CPUS */
727
728 #ifdef CONFIG_PROC_FS
729 int __init
730 setup_profiling_timer(unsigned int multiplier)
731 {
732 return -EINVAL;
733 }
734 #endif