[PARISC] Allow nested interrupts
[linux-2.6/openmoko-kernel/knife-kernel.git] / arch / parisc / kernel / smp.c
blobfaad338f310ed12f8dddc4f4824b40c61edde298
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! :^)
11 ** Thanks to John Curry and Ullas Ponnadi. I learned alot from their work.
12 ** -grant (1/12/2001)
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.
19 #undef ENTRY_SYS_CPUS /* syscall support for iCOD-like functionality */
22 #include <linux/types.h>
23 #include <linux/spinlock.h>
24 #include <linux/slab.h>
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/sched.h>
29 #include <linux/init.h>
30 #include <linux/interrupt.h>
31 #include <linux/smp.h>
32 #include <linux/kernel_stat.h>
33 #include <linux/mm.h>
34 #include <linux/delay.h>
35 #include <linux/bitops.h>
37 #include <asm/system.h>
38 #include <asm/atomic.h>
39 #include <asm/current.h>
40 #include <asm/delay.h>
41 #include <asm/tlbflush.h>
43 #include <asm/io.h>
44 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
45 #include <asm/mmu_context.h>
46 #include <asm/page.h>
47 #include <asm/pgtable.h>
48 #include <asm/pgalloc.h>
49 #include <asm/processor.h>
50 #include <asm/ptrace.h>
51 #include <asm/unistd.h>
52 #include <asm/cacheflush.h>
54 #define kDEBUG 0
56 DEFINE_SPINLOCK(smp_lock);
58 volatile struct task_struct *smp_init_current_idle_task;
60 static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */
62 static int parisc_max_cpus __read_mostly = 1;
64 /* online cpus are ones that we've managed to bring up completely
65 * possible cpus are all valid cpu
66 * present cpus are all detected cpu
68 * On startup we bring up the "possible" cpus. Since we discover
69 * CPUs later, we add them as hotplug, so the possible cpu mask is
70 * empty in the beginning.
73 cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */
74 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */
76 EXPORT_SYMBOL(cpu_online_map);
77 EXPORT_SYMBOL(cpu_possible_map);
80 struct smp_call_struct {
81 void (*func) (void *info);
82 void *info;
83 long wait;
84 atomic_t unstarted_count;
85 atomic_t unfinished_count;
87 static volatile struct smp_call_struct *smp_call_function_data;
89 enum ipi_message_type {
90 IPI_NOP=0,
91 IPI_RESCHEDULE=1,
92 IPI_CALL_FUNC,
93 IPI_CPU_START,
94 IPI_CPU_STOP,
95 IPI_CPU_TEST
99 /********** SMP inter processor interrupt and communication routines */
101 #undef PER_CPU_IRQ_REGION
102 #ifdef PER_CPU_IRQ_REGION
103 /* XXX REVISIT Ignore for now.
104 ** *May* need this "hook" to register IPI handler
105 ** once we have perCPU ExtIntr switch tables.
107 static void
108 ipi_init(int cpuid)
111 /* If CPU is present ... */
112 #ifdef ENTRY_SYS_CPUS
113 /* *and* running (not stopped) ... */
114 #error iCOD support wants state checked here.
115 #endif
117 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
119 if(cpu_online(cpuid) )
121 switch_to_idle_task(current);
124 return;
126 #endif
130 ** Yoink this CPU from the runnable list...
133 static void
134 halt_processor(void)
136 #ifdef ENTRY_SYS_CPUS
137 #error halt_processor() needs rework
139 ** o migrate I/O interrupts off this CPU.
140 ** o leave IPI enabled - __cli() will disable IPI.
141 ** o leave CPU in online map - just change the state
143 cpu_data[this_cpu].state = STATE_STOPPED;
144 mark_bh(IPI_BH);
145 #else
146 /* REVISIT : redirect I/O Interrupts to another CPU? */
147 /* REVISIT : does PM *know* this CPU isn't available? */
148 cpu_clear(smp_processor_id(), cpu_online_map);
149 local_irq_disable();
150 for (;;)
152 #endif
156 irqreturn_t
157 ipi_interrupt(int irq, void *dev_id, struct pt_regs *regs)
159 int this_cpu = smp_processor_id();
160 struct cpuinfo_parisc *p = &cpu_data[this_cpu];
161 unsigned long ops;
162 unsigned long flags;
164 /* Count this now; we may make a call that never returns. */
165 p->ipi_count++;
167 mb(); /* Order interrupt and bit testing. */
169 for (;;) {
170 spin_lock_irqsave(&(p->lock),flags);
171 ops = p->pending_ipi;
172 p->pending_ipi = 0;
173 spin_unlock_irqrestore(&(p->lock),flags);
175 mb(); /* Order bit clearing and data access. */
177 if (!ops)
178 break;
180 while (ops) {
181 unsigned long which = ffz(~ops);
183 ops &= ~(1 << which);
185 switch (which) {
186 case IPI_NOP:
187 #if (kDEBUG>=100)
188 printk(KERN_DEBUG "CPU%d IPI_NOP\n",this_cpu);
189 #endif /* kDEBUG */
190 break;
192 case IPI_RESCHEDULE:
193 #if (kDEBUG>=100)
194 printk(KERN_DEBUG "CPU%d IPI_RESCHEDULE\n",this_cpu);
195 #endif /* kDEBUG */
197 * Reschedule callback. Everything to be
198 * done is done by the interrupt return path.
200 break;
202 case IPI_CALL_FUNC:
203 #if (kDEBUG>=100)
204 printk(KERN_DEBUG "CPU%d IPI_CALL_FUNC\n",this_cpu);
205 #endif /* kDEBUG */
207 volatile struct smp_call_struct *data;
208 void (*func)(void *info);
209 void *info;
210 int wait;
212 data = smp_call_function_data;
213 func = data->func;
214 info = data->info;
215 wait = data->wait;
217 mb();
218 atomic_dec ((atomic_t *)&data->unstarted_count);
220 /* At this point, *data can't
221 * be relied upon.
224 (*func)(info);
226 /* Notify the sending CPU that the
227 * task is done.
229 mb();
230 if (wait)
231 atomic_dec ((atomic_t *)&data->unfinished_count);
233 break;
235 case IPI_CPU_START:
236 #if (kDEBUG>=100)
237 printk(KERN_DEBUG "CPU%d IPI_CPU_START\n",this_cpu);
238 #endif /* kDEBUG */
239 #ifdef ENTRY_SYS_CPUS
240 p->state = STATE_RUNNING;
241 #endif
242 break;
244 case IPI_CPU_STOP:
245 #if (kDEBUG>=100)
246 printk(KERN_DEBUG "CPU%d IPI_CPU_STOP\n",this_cpu);
247 #endif /* kDEBUG */
248 #ifdef ENTRY_SYS_CPUS
249 #else
250 halt_processor();
251 #endif
252 break;
254 case IPI_CPU_TEST:
255 #if (kDEBUG>=100)
256 printk(KERN_DEBUG "CPU%d is alive!\n",this_cpu);
257 #endif /* kDEBUG */
258 break;
260 default:
261 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
262 this_cpu, which);
263 return IRQ_NONE;
264 } /* Switch */
265 /* let in any pending interrupts */
266 local_irq_enable();
267 local_irq_disable();
268 } /* while (ops) */
270 return IRQ_HANDLED;
274 static inline void
275 ipi_send(int cpu, enum ipi_message_type op)
277 struct cpuinfo_parisc *p = &cpu_data[cpu];
278 unsigned long flags;
280 spin_lock_irqsave(&(p->lock),flags);
281 p->pending_ipi |= 1 << op;
282 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa);
283 spin_unlock_irqrestore(&(p->lock),flags);
287 static inline void
288 send_IPI_single(int dest_cpu, enum ipi_message_type op)
290 if (dest_cpu == NO_PROC_ID) {
291 BUG();
292 return;
295 ipi_send(dest_cpu, op);
298 static inline void
299 send_IPI_allbutself(enum ipi_message_type op)
301 int i;
303 for_each_online_cpu(i) {
304 if (i != smp_processor_id())
305 send_IPI_single(i, op);
310 inline void
311 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
313 static inline void
314 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); }
316 void
317 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
319 void
320 smp_send_all_nop(void)
322 send_IPI_allbutself(IPI_NOP);
327 * Run a function on all other CPUs.
328 * <func> The function to run. This must be fast and non-blocking.
329 * <info> An arbitrary pointer to pass to the function.
330 * <retry> If true, keep retrying until ready.
331 * <wait> If true, wait until function has completed on other CPUs.
332 * [RETURNS] 0 on success, else a negative status code.
334 * Does not return until remote CPUs are nearly ready to execute <func>
335 * or have executed.
339 smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
341 struct smp_call_struct data;
342 unsigned long timeout;
343 static DEFINE_SPINLOCK(lock);
344 int retries = 0;
346 if (num_online_cpus() < 2)
347 return 0;
349 /* Can deadlock when called with interrupts disabled */
350 WARN_ON(irqs_disabled());
352 /* can also deadlock if IPIs are disabled */
353 WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0);
356 data.func = func;
357 data.info = info;
358 data.wait = wait;
359 atomic_set(&data.unstarted_count, num_online_cpus() - 1);
360 atomic_set(&data.unfinished_count, num_online_cpus() - 1);
362 if (retry) {
363 spin_lock (&lock);
364 while (smp_call_function_data != 0)
365 barrier();
367 else {
368 spin_lock (&lock);
369 if (smp_call_function_data) {
370 spin_unlock (&lock);
371 return -EBUSY;
375 smp_call_function_data = &data;
376 spin_unlock (&lock);
378 /* Send a message to all other CPUs and wait for them to respond */
379 send_IPI_allbutself(IPI_CALL_FUNC);
381 retry:
382 /* Wait for response */
383 timeout = jiffies + HZ;
384 while ( (atomic_read (&data.unstarted_count) > 0) &&
385 time_before (jiffies, timeout) )
386 barrier ();
388 if (atomic_read (&data.unstarted_count) > 0) {
389 printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n",
390 smp_processor_id(), ++retries);
391 goto retry;
393 /* We either got one or timed out. Release the lock */
395 mb();
396 smp_call_function_data = NULL;
398 while (wait && atomic_read (&data.unfinished_count) > 0)
399 barrier ();
401 return 0;
404 EXPORT_SYMBOL(smp_call_function);
407 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu()
408 * as we want to ensure all TLB's flushed before proceeding.
411 void
412 smp_flush_tlb_all(void)
414 on_each_cpu(flush_tlb_all_local, NULL, 1, 1);
418 void
419 smp_do_timer(struct pt_regs *regs)
421 int cpu = smp_processor_id();
422 struct cpuinfo_parisc *data = &cpu_data[cpu];
424 if (!--data->prof_counter) {
425 data->prof_counter = data->prof_multiplier;
426 update_process_times(user_mode(regs));
431 * Called by secondaries to update state and initialize CPU registers.
433 static void __init
434 smp_cpu_init(int cpunum)
436 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */
437 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
438 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
440 /* Set modes and Enable floating point coprocessor */
441 (void) init_per_cpu(cpunum);
443 disable_sr_hashing();
445 mb();
447 /* Well, support 2.4 linux scheme as well. */
448 if (cpu_test_and_set(cpunum, cpu_online_map))
450 extern void machine_halt(void); /* arch/parisc.../process.c */
452 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
453 machine_halt();
456 /* Initialise the idle task for this CPU */
457 atomic_inc(&init_mm.mm_count);
458 current->active_mm = &init_mm;
459 if(current->mm)
460 BUG();
461 enter_lazy_tlb(&init_mm, current);
463 init_IRQ(); /* make sure no IRQ's are enabled or pending */
464 start_cpu_itimer();
469 * Slaves start using C here. Indirectly called from smp_slave_stext.
470 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
472 void __init smp_callin(void)
474 int slave_id = cpu_now_booting;
475 #if 0
476 void *istack;
477 #endif
479 smp_cpu_init(slave_id);
480 preempt_disable();
482 #if 0 /* NOT WORKING YET - see entry.S */
483 istack = (void *)__get_free_pages(GFP_KERNEL,ISTACK_ORDER);
484 if (istack == NULL) {
485 printk(KERN_CRIT "Failed to allocate interrupt stack for cpu %d\n",slave_id);
486 BUG();
488 mtctl(istack,31);
489 #endif
491 flush_cache_all_local(); /* start with known state */
492 flush_tlb_all_local(NULL);
494 local_irq_enable(); /* Interrupts have been off until now */
496 cpu_idle(); /* Wait for timer to schedule some work */
498 /* NOTREACHED */
499 panic("smp_callin() AAAAaaaaahhhh....\n");
503 * Bring one cpu online.
505 int __init smp_boot_one_cpu(int cpuid)
507 struct task_struct *idle;
508 long timeout;
511 * Create an idle task for this CPU. Note the address wed* give
512 * to kernel_thread is irrelevant -- it's going to start
513 * where OS_BOOT_RENDEVZ vector in SAL says to start. But
514 * this gets all the other task-y sort of data structures set
515 * up like we wish. We need to pull the just created idle task
516 * off the run queue and stuff it into the init_tasks[] array.
517 * Sheesh . . .
520 idle = fork_idle(cpuid);
521 if (IS_ERR(idle))
522 panic("SMP: fork failed for CPU:%d", cpuid);
524 task_thread_info(idle)->cpu = cpuid;
526 /* Let _start know what logical CPU we're booting
527 ** (offset into init_tasks[],cpu_data[])
529 cpu_now_booting = cpuid;
532 ** boot strap code needs to know the task address since
533 ** it also contains the process stack.
535 smp_init_current_idle_task = idle ;
536 mb();
538 printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa);
541 ** This gets PDC to release the CPU from a very tight loop.
543 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
544 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
545 ** is executed after receiving the rendezvous signal (an interrupt to
546 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
547 ** contents of memory are valid."
549 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa);
550 mb();
553 * OK, wait a bit for that CPU to finish staggering about.
554 * Slave will set a bit when it reaches smp_cpu_init().
555 * Once the "monarch CPU" sees the bit change, it can move on.
557 for (timeout = 0; timeout < 10000; timeout++) {
558 if(cpu_online(cpuid)) {
559 /* Which implies Slave has started up */
560 cpu_now_booting = 0;
561 smp_init_current_idle_task = NULL;
562 goto alive ;
564 udelay(100);
565 barrier();
568 put_task_struct(idle);
569 idle = NULL;
571 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
572 return -1;
574 alive:
575 /* Remember the Slave data */
576 #if (kDEBUG>=100)
577 printk(KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
578 cpuid, timeout * 100);
579 #endif /* kDEBUG */
580 #ifdef ENTRY_SYS_CPUS
581 cpu_data[cpuid].state = STATE_RUNNING;
582 #endif
583 return 0;
586 void __devinit smp_prepare_boot_cpu(void)
588 int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */
590 #ifdef ENTRY_SYS_CPUS
591 cpu_data[0].state = STATE_RUNNING;
592 #endif
594 /* Setup BSP mappings */
595 printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor);
597 cpu_set(bootstrap_processor, cpu_online_map);
598 cpu_set(bootstrap_processor, cpu_present_map);
604 ** inventory.c:do_inventory() hasn't yet been run and thus we
605 ** don't 'discover' the additional CPU's until later.
607 void __init smp_prepare_cpus(unsigned int max_cpus)
609 cpus_clear(cpu_present_map);
610 cpu_set(0, cpu_present_map);
612 parisc_max_cpus = max_cpus;
613 if (!max_cpus)
614 printk(KERN_INFO "SMP mode deactivated.\n");
618 void smp_cpus_done(unsigned int cpu_max)
620 return;
624 int __devinit __cpu_up(unsigned int cpu)
626 if (cpu != 0 && cpu < parisc_max_cpus)
627 smp_boot_one_cpu(cpu);
629 return cpu_online(cpu) ? 0 : -ENOSYS;
634 #ifdef ENTRY_SYS_CPUS
635 /* Code goes along with:
636 ** entry.s: ENTRY_NAME(sys_cpus) / * 215, for cpu stat * /
638 int sys_cpus(int argc, char **argv)
640 int i,j=0;
641 extern int current_pid(int cpu);
643 if( argc > 2 ) {
644 printk("sys_cpus:Only one argument supported\n");
645 return (-1);
647 if ( argc == 1 ){
649 #ifdef DUMP_MORE_STATE
650 for_each_online_cpu(i) {
651 int cpus_per_line = 4;
653 if (j++ % cpus_per_line)
654 printk(" %3d",i);
655 else
656 printk("\n %3d",i);
658 printk("\n");
659 #else
660 printk("\n 0\n");
661 #endif
662 } else if((argc==2) && !(strcmp(argv[1],"-l"))) {
663 printk("\nCPUSTATE TASK CPUNUM CPUID HARDCPU(HPA)\n");
664 #ifdef DUMP_MORE_STATE
665 for_each_online_cpu(i) {
666 if (cpu_data[i].cpuid != NO_PROC_ID) {
667 switch(cpu_data[i].state) {
668 case STATE_RENDEZVOUS:
669 printk("RENDEZVS ");
670 break;
671 case STATE_RUNNING:
672 printk((current_pid(i)!=0) ? "RUNNING " : "IDLING ");
673 break;
674 case STATE_STOPPED:
675 printk("STOPPED ");
676 break;
677 case STATE_HALTED:
678 printk("HALTED ");
679 break;
680 default:
681 printk("%08x?", cpu_data[i].state);
682 break;
684 if(cpu_online(i)) {
685 printk(" %4d",current_pid(i));
687 printk(" %6d",cpu_number_map(i));
688 printk(" %5d",i);
689 printk(" 0x%lx\n",cpu_data[i].hpa);
692 #else
693 printk("\n%s %4d 0 0 --------",
694 (current->pid)?"RUNNING ": "IDLING ",current->pid);
695 #endif
696 } else if ((argc==2) && !(strcmp(argv[1],"-s"))) {
697 #ifdef DUMP_MORE_STATE
698 printk("\nCPUSTATE CPUID\n");
699 for_each_online_cpu(i) {
700 if (cpu_data[i].cpuid != NO_PROC_ID) {
701 switch(cpu_data[i].state) {
702 case STATE_RENDEZVOUS:
703 printk("RENDEZVS");break;
704 case STATE_RUNNING:
705 printk((current_pid(i)!=0) ? "RUNNING " : "IDLING");
706 break;
707 case STATE_STOPPED:
708 printk("STOPPED ");break;
709 case STATE_HALTED:
710 printk("HALTED ");break;
711 default:
713 printk(" %5d\n",i);
716 #else
717 printk("\n%s CPU0",(current->pid==0)?"RUNNING ":"IDLING ");
718 #endif
719 } else {
720 printk("sys_cpus:Unknown request\n");
721 return (-1);
723 return 0;
725 #endif /* ENTRY_SYS_CPUS */
727 #ifdef CONFIG_PROC_FS
728 int __init
729 setup_profiling_timer(unsigned int multiplier)
731 return -EINVAL;
733 #endif