1 /*
2 * Code to handle x86 style IRQs plus some generic interrupt stuff.
3 *
4 * Copyright (C) 1992 Linus Torvalds
5 * Copyright (C) 1994, 1995, 1996, 1997, 1998 Ralf Baechle
6 * Copyright (C) 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
7 * Copyright (C) 1999-2000 Grant Grundler
8 * Copyright (c) 2005 Matthew Wilcox
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2, or (at your option)
13 * any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 */
24 #include <linux/bitops.h>
25 #include <linux/errno.h>
26 #include <linux/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/kernel_stat.h>
29 #include <linux/seq_file.h>
30 #include <linux/types.h>
31 #include <asm/io.h>
32
33 #include <asm/smp.h>
34 #include <asm/ldcw.h>
35
36 #undef PARISC_IRQ_CR16_COUNTS
37
38 extern irqreturn_t timer_interrupt(int, void *);
39 extern irqreturn_t ipi_interrupt(int, void *);
40
41 #define EIEM_MASK(irq) (1UL<<(CPU_IRQ_MAX - irq))
42
43 /* Bits in EIEM correlate with cpu_irq_action[].
44 ** Numbered *Big Endian*! (ie bit 0 is MSB)
45 */
46 static volatile unsigned long cpu_eiem = 0;
47
48 /*
49 ** local ACK bitmap ... habitually set to 1, but reset to zero
50 ** between ->ack() and ->end() of the interrupt to prevent
51 ** re-interruption of a processing interrupt.
52 */
53 static DEFINE_PER_CPU(unsigned long, local_ack_eiem) = ~0UL;
54
cpu_mask_irq(struct irq_data * d)55 static void cpu_mask_irq(struct irq_data *d)
56 {
57 unsigned long eirr_bit = EIEM_MASK(d->irq);
58
59 cpu_eiem &= ~eirr_bit;
60 /* Do nothing on the other CPUs. If they get this interrupt,
61 * The & cpu_eiem in the do_cpu_irq_mask() ensures they won't
62 * handle it, and the set_eiem() at the bottom will ensure it
63 * then gets disabled */
64 }
65
__cpu_unmask_irq(unsigned int irq)66 static void __cpu_unmask_irq(unsigned int irq)
67 {
68 unsigned long eirr_bit = EIEM_MASK(irq);
69
70 cpu_eiem |= eirr_bit;
71
72 /* This is just a simple NOP IPI. But what it does is cause
73 * all the other CPUs to do a set_eiem(cpu_eiem) at the end
74 * of the interrupt handler */
75 smp_send_all_nop();
76 }
77
cpu_unmask_irq(struct irq_data * d)78 static void cpu_unmask_irq(struct irq_data *d)
79 {
80 __cpu_unmask_irq(d->irq);
81 }
82
cpu_ack_irq(struct irq_data * d)83 void cpu_ack_irq(struct irq_data *d)
84 {
85 unsigned long mask = EIEM_MASK(d->irq);
86 int cpu = smp_processor_id();
87
88 /* Clear in EIEM so we can no longer process */
89 per_cpu(local_ack_eiem, cpu) &= ~mask;
90
91 /* disable the interrupt */
92 set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
93
94 /* and now ack it */
95 mtctl(mask, 23);
96 }
97
cpu_eoi_irq(struct irq_data * d)98 void cpu_eoi_irq(struct irq_data *d)
99 {
100 unsigned long mask = EIEM_MASK(d->irq);
101 int cpu = smp_processor_id();
102
103 /* set it in the eiems---it's no longer in process */
104 per_cpu(local_ack_eiem, cpu) |= mask;
105
106 /* enable the interrupt */
107 set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
108 }
109
110 #ifdef CONFIG_SMP
cpu_check_affinity(struct irq_data * d,const struct cpumask * dest)111 int cpu_check_affinity(struct irq_data *d, const struct cpumask *dest)
112 {
113 int cpu_dest;
114
115 /* timer and ipi have to always be received on all CPUs */
116 if (irqd_is_per_cpu(d))
117 return -EINVAL;
118
119 /* whatever mask they set, we just allow one CPU */
120 cpu_dest = cpumask_first_and(dest, cpu_online_mask);
121
122 return cpu_dest;
123 }
124
cpu_set_affinity_irq(struct irq_data * d,const struct cpumask * dest,bool force)125 static int cpu_set_affinity_irq(struct irq_data *d, const struct cpumask *dest,
126 bool force)
127 {
128 int cpu_dest;
129
130 cpu_dest = cpu_check_affinity(d, dest);
131 if (cpu_dest < 0)
132 return -1;
133
134 cpumask_copy(d->affinity, dest);
135
136 return 0;
137 }
138 #endif
139
140 static struct irq_chip cpu_interrupt_type = {
141 .name = "CPU",
142 .irq_mask = cpu_mask_irq,
143 .irq_unmask = cpu_unmask_irq,
144 .irq_ack = cpu_ack_irq,
145 .irq_eoi = cpu_eoi_irq,
146 #ifdef CONFIG_SMP
147 .irq_set_affinity = cpu_set_affinity_irq,
148 #endif
149 /* XXX: Needs to be written. We managed without it so far, but
150 * we really ought to write it.
151 */
152 .irq_retrigger = NULL,
153 };
154
155 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
156 #define irq_stats(x) (&per_cpu(irq_stat, x))
157
158 /*
159 * /proc/interrupts printing for arch specific interrupts
160 */
arch_show_interrupts(struct seq_file * p,int prec)161 int arch_show_interrupts(struct seq_file *p, int prec)
162 {
163 int j;
164
165 #ifdef CONFIG_DEBUG_STACKOVERFLOW
166 seq_printf(p, "%*s: ", prec, "STK");
167 for_each_online_cpu(j)
168 seq_printf(p, "%10u ", irq_stats(j)->kernel_stack_usage);
169 seq_puts(p, " Kernel stack usage\n");
170 # ifdef CONFIG_IRQSTACKS
171 seq_printf(p, "%*s: ", prec, "IST");
172 for_each_online_cpu(j)
173 seq_printf(p, "%10u ", irq_stats(j)->irq_stack_usage);
174 seq_puts(p, " Interrupt stack usage\n");
175 # endif
176 #endif
177 #ifdef CONFIG_SMP
178 seq_printf(p, "%*s: ", prec, "RES");
179 for_each_online_cpu(j)
180 seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
181 seq_puts(p, " Rescheduling interrupts\n");
182 #endif
183 seq_printf(p, "%*s: ", prec, "UAH");
184 for_each_online_cpu(j)
185 seq_printf(p, "%10u ", irq_stats(j)->irq_unaligned_count);
186 seq_puts(p, " Unaligned access handler traps\n");
187 seq_printf(p, "%*s: ", prec, "FPA");
188 for_each_online_cpu(j)
189 seq_printf(p, "%10u ", irq_stats(j)->irq_fpassist_count);
190 seq_puts(p, " Floating point assist traps\n");
191 seq_printf(p, "%*s: ", prec, "TLB");
192 for_each_online_cpu(j)
193 seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
194 seq_puts(p, " TLB shootdowns\n");
195 return 0;
196 }
197
show_interrupts(struct seq_file * p,void * v)198 int show_interrupts(struct seq_file *p, void *v)
199 {
200 int i = *(loff_t *) v, j;
201 unsigned long flags;
202
203 if (i == 0) {
204 seq_puts(p, " ");
205 for_each_online_cpu(j)
206 seq_printf(p, " CPU%d", j);
207
208 #ifdef PARISC_IRQ_CR16_COUNTS
209 seq_printf(p, " [min/avg/max] (CPU cycle counts)");
210 #endif
211 seq_putc(p, '\n');
212 }
213
214 if (i < NR_IRQS) {
215 struct irq_desc *desc = irq_to_desc(i);
216 struct irqaction *action;
217
218 raw_spin_lock_irqsave(&desc->lock, flags);
219 action = desc->action;
220 if (!action)
221 goto skip;
222 seq_printf(p, "%3d: ", i);
223 #ifdef CONFIG_SMP
224 for_each_online_cpu(j)
225 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
226 #else
227 seq_printf(p, "%10u ", kstat_irqs(i));
228 #endif
229
230 seq_printf(p, " %14s", irq_desc_get_chip(desc)->name);
231 #ifndef PARISC_IRQ_CR16_COUNTS
232 seq_printf(p, " %s", action->name);
233
234 while ((action = action->next))
235 seq_printf(p, ", %s", action->name);
236 #else
237 for ( ;action; action = action->next) {
238 unsigned int k, avg, min, max;
239
240 min = max = action->cr16_hist[0];
241
242 for (avg = k = 0; k < PARISC_CR16_HIST_SIZE; k++) {
243 int hist = action->cr16_hist[k];
244
245 if (hist) {
246 avg += hist;
247 } else
248 break;
249
250 if (hist > max) max = hist;
251 if (hist < min) min = hist;
252 }
253
254 avg /= k;
255 seq_printf(p, " %s[%d/%d/%d]", action->name,
256 min,avg,max);
257 }
258 #endif
259
260 seq_putc(p, '\n');
261 skip:
262 raw_spin_unlock_irqrestore(&desc->lock, flags);
263 }
264
265 if (i == NR_IRQS)
266 arch_show_interrupts(p, 3);
267
268 return 0;
269 }
270
271
272
273 /*
274 ** The following form a "set": Virtual IRQ, Transaction Address, Trans Data.
275 ** Respectively, these map to IRQ region+EIRR, Processor HPA, EIRR bit.
276 **
277 ** To use txn_XXX() interfaces, get a Virtual IRQ first.
278 ** Then use that to get the Transaction address and data.
279 */
280
cpu_claim_irq(unsigned int irq,struct irq_chip * type,void * data)281 int cpu_claim_irq(unsigned int irq, struct irq_chip *type, void *data)
282 {
283 if (irq_has_action(irq))
284 return -EBUSY;
285 if (irq_get_chip(irq) != &cpu_interrupt_type)
286 return -EBUSY;
287
288 /* for iosapic interrupts */
289 if (type) {
290 irq_set_chip_and_handler(irq, type, handle_percpu_irq);
291 irq_set_chip_data(irq, data);
292 __cpu_unmask_irq(irq);
293 }
294 return 0;
295 }
296
txn_claim_irq(int irq)297 int txn_claim_irq(int irq)
298 {
299 return cpu_claim_irq(irq, NULL, NULL) ? -1 : irq;
300 }
301
302 /*
303 * The bits_wide parameter accommodates the limitations of the HW/SW which
304 * use these bits:
305 * Legacy PA I/O (GSC/NIO): 5 bits (architected EIM register)
306 * V-class (EPIC): 6 bits
307 * N/L/A-class (iosapic): 8 bits
308 * PCI 2.2 MSI: 16 bits
309 * Some PCI devices: 32 bits (Symbios SCSI/ATM/HyperFabric)
310 *
311 * On the service provider side:
312 * o PA 1.1 (and PA2.0 narrow mode) 5-bits (width of EIR register)
313 * o PA 2.0 wide mode 6-bits (per processor)
314 * o IA64 8-bits (0-256 total)
315 *
316 * So a Legacy PA I/O device on a PA 2.0 box can't use all the bits supported
317 * by the processor...and the N/L-class I/O subsystem supports more bits than
318 * PA2.0 has. The first case is the problem.
319 */
txn_alloc_irq(unsigned int bits_wide)320 int txn_alloc_irq(unsigned int bits_wide)
321 {
322 int irq;
323
324 /* never return irq 0 cause that's the interval timer */
325 for (irq = CPU_IRQ_BASE + 1; irq <= CPU_IRQ_MAX; irq++) {
326 if (cpu_claim_irq(irq, NULL, NULL) < 0)
327 continue;
328 if ((irq - CPU_IRQ_BASE) >= (1 << bits_wide))
329 continue;
330 return irq;
331 }
332
333 /* unlikely, but be prepared */
334 return -1;
335 }
336
337
txn_affinity_addr(unsigned int irq,int cpu)338 unsigned long txn_affinity_addr(unsigned int irq, int cpu)
339 {
340 #ifdef CONFIG_SMP
341 struct irq_data *d = irq_get_irq_data(irq);
342 cpumask_copy(d->affinity, cpumask_of(cpu));
343 #endif
344
345 return per_cpu(cpu_data, cpu).txn_addr;
346 }
347
348
txn_alloc_addr(unsigned int virt_irq)349 unsigned long txn_alloc_addr(unsigned int virt_irq)
350 {
351 static int next_cpu = -1;
352
353 next_cpu++; /* assign to "next" CPU we want this bugger on */
354
355 /* validate entry */
356 while ((next_cpu < nr_cpu_ids) &&
357 (!per_cpu(cpu_data, next_cpu).txn_addr ||
358 !cpu_online(next_cpu)))
359 next_cpu++;
360
361 if (next_cpu >= nr_cpu_ids)
362 next_cpu = 0; /* nothing else, assign monarch */
363
364 return txn_affinity_addr(virt_irq, next_cpu);
365 }
366
367
txn_alloc_data(unsigned int virt_irq)368 unsigned int txn_alloc_data(unsigned int virt_irq)
369 {
370 return virt_irq - CPU_IRQ_BASE;
371 }
372
eirr_to_irq(unsigned long eirr)373 static inline int eirr_to_irq(unsigned long eirr)
374 {
375 int bit = fls_long(eirr);
376 return (BITS_PER_LONG - bit) + TIMER_IRQ;
377 }
378
379 #ifdef CONFIG_IRQSTACKS
380 /*
381 * IRQ STACK - used for irq handler
382 */
383 #define IRQ_STACK_SIZE (4096 << 2) /* 16k irq stack size */
384
385 union irq_stack_union {
386 unsigned long stack[IRQ_STACK_SIZE/sizeof(unsigned long)];
387 volatile unsigned int slock[4];
388 volatile unsigned int lock[1];
389 };
390
391 DEFINE_PER_CPU(union irq_stack_union, irq_stack_union) = {
392 .slock = { 1,1,1,1 },
393 };
394 #endif
395
396
397 int sysctl_panic_on_stackoverflow = 1;
398
stack_overflow_check(struct pt_regs * regs)399 static inline void stack_overflow_check(struct pt_regs *regs)
400 {
401 #ifdef CONFIG_DEBUG_STACKOVERFLOW
402 #define STACK_MARGIN (256*6)
403
404 /* Our stack starts directly behind the thread_info struct. */
405 unsigned long stack_start = (unsigned long) current_thread_info();
406 unsigned long sp = regs->gr[30];
407 unsigned long stack_usage;
408 unsigned int *last_usage;
409 int cpu = smp_processor_id();
410
411 /* if sr7 != 0, we interrupted a userspace process which we do not want
412 * to check for stack overflow. We will only check the kernel stack. */
413 if (regs->sr[7])
414 return;
415
416 /* calculate kernel stack usage */
417 stack_usage = sp - stack_start;
418 #ifdef CONFIG_IRQSTACKS
419 if (likely(stack_usage <= THREAD_SIZE))
420 goto check_kernel_stack; /* found kernel stack */
421
422 /* check irq stack usage */
423 stack_start = (unsigned long) &per_cpu(irq_stack_union, cpu).stack;
424 stack_usage = sp - stack_start;
425
426 last_usage = &per_cpu(irq_stat.irq_stack_usage, cpu);
427 if (unlikely(stack_usage > *last_usage))
428 *last_usage = stack_usage;
429
430 if (likely(stack_usage < (IRQ_STACK_SIZE - STACK_MARGIN)))
431 return;
432
433 pr_emerg("stackcheck: %s will most likely overflow irq stack "
434 "(sp:%lx, stk bottom-top:%lx-%lx)\n",
435 current->comm, sp, stack_start, stack_start + IRQ_STACK_SIZE);
436 goto panic_check;
437
438 check_kernel_stack:
439 #endif
440
441 /* check kernel stack usage */
442 last_usage = &per_cpu(irq_stat.kernel_stack_usage, cpu);
443
444 if (unlikely(stack_usage > *last_usage))
445 *last_usage = stack_usage;
446
447 if (likely(stack_usage < (THREAD_SIZE - STACK_MARGIN)))
448 return;
449
450 pr_emerg("stackcheck: %s will most likely overflow kernel stack "
451 "(sp:%lx, stk bottom-top:%lx-%lx)\n",
452 current->comm, sp, stack_start, stack_start + THREAD_SIZE);
453
454 #ifdef CONFIG_IRQSTACKS
455 panic_check:
456 #endif
457 if (sysctl_panic_on_stackoverflow)
458 panic("low stack detected by irq handler - check messages\n");
459 #endif
460 }
461
462 #ifdef CONFIG_IRQSTACKS
463 /* in entry.S: */
464 void call_on_stack(unsigned long p1, void *func, unsigned long new_stack);
465
execute_on_irq_stack(void * func,unsigned long param1)466 static void execute_on_irq_stack(void *func, unsigned long param1)
467 {
468 union irq_stack_union *union_ptr;
469 unsigned long irq_stack;
470 volatile unsigned int *irq_stack_in_use;
471
472 union_ptr = &per_cpu(irq_stack_union, smp_processor_id());
473 irq_stack = (unsigned long) &union_ptr->stack;
474 irq_stack = ALIGN(irq_stack + sizeof(irq_stack_union.slock),
475 64); /* align for stack frame usage */
476
477 /* We may be called recursive. If we are already using the irq stack,
478 * just continue to use it. Use spinlocks to serialize
479 * the irq stack usage.
480 */
481 irq_stack_in_use = (volatile unsigned int *)__ldcw_align(union_ptr);
482 if (!__ldcw(irq_stack_in_use)) {
483 void (*direct_call)(unsigned long p1) = func;
484
485 /* We are using the IRQ stack already.
486 * Do direct call on current stack. */
487 direct_call(param1);
488 return;
489 }
490
491 /* This is where we switch to the IRQ stack. */
492 call_on_stack(param1, func, irq_stack);
493
494 /* free up irq stack usage. */
495 *irq_stack_in_use = 1;
496 }
497
do_softirq_own_stack(void)498 void do_softirq_own_stack(void)
499 {
500 execute_on_irq_stack(__do_softirq, 0);
501 }
502 #endif /* CONFIG_IRQSTACKS */
503
504 /* ONLY called from entry.S:intr_extint() */
do_cpu_irq_mask(struct pt_regs * regs)505 void do_cpu_irq_mask(struct pt_regs *regs)
506 {
507 struct pt_regs *old_regs;
508 unsigned long eirr_val;
509 int irq, cpu = smp_processor_id();
510 struct irq_desc *desc;
511 #ifdef CONFIG_SMP
512 cpumask_t dest;
513 #endif
514
515 old_regs = set_irq_regs(regs);
516 local_irq_disable();
517 irq_enter();
518
519 eirr_val = mfctl(23) & cpu_eiem & per_cpu(local_ack_eiem, cpu);
520 if (!eirr_val)
521 goto set_out;
522 irq = eirr_to_irq(eirr_val);
523
524 /* Filter out spurious interrupts, mostly from serial port at bootup */
525 desc = irq_to_desc(irq);
526 if (unlikely(!desc->action))
527 goto set_out;
528
529 #ifdef CONFIG_SMP
530 cpumask_copy(&dest, desc->irq_data.affinity);
531 if (irqd_is_per_cpu(&desc->irq_data) &&
532 !cpu_isset(smp_processor_id(), dest)) {
533 int cpu = first_cpu(dest);
534
535 printk(KERN_DEBUG "redirecting irq %d from CPU %d to %d\n",
536 irq, smp_processor_id(), cpu);
537 gsc_writel(irq + CPU_IRQ_BASE,
538 per_cpu(cpu_data, cpu).hpa);
539 goto set_out;
540 }
541 #endif
542 stack_overflow_check(regs);
543
544 #ifdef CONFIG_IRQSTACKS
545 execute_on_irq_stack(&generic_handle_irq, irq);
546 #else
547 generic_handle_irq(irq);
548 #endif /* CONFIG_IRQSTACKS */
549
550 out:
551 irq_exit();
552 set_irq_regs(old_regs);
553 return;
554
555 set_out:
556 set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
557 goto out;
558 }
559
560 static struct irqaction timer_action = {
561 .handler = timer_interrupt,
562 .name = "timer",
563 .flags = IRQF_TIMER | IRQF_PERCPU | IRQF_IRQPOLL,
564 };
565
566 #ifdef CONFIG_SMP
567 static struct irqaction ipi_action = {
568 .handler = ipi_interrupt,
569 .name = "IPI",
570 .flags = IRQF_PERCPU,
571 };
572 #endif
573
claim_cpu_irqs(void)574 static void claim_cpu_irqs(void)
575 {
576 int i;
577 for (i = CPU_IRQ_BASE; i <= CPU_IRQ_MAX; i++) {
578 irq_set_chip_and_handler(i, &cpu_interrupt_type,
579 handle_percpu_irq);
580 }
581
582 irq_set_handler(TIMER_IRQ, handle_percpu_irq);
583 setup_irq(TIMER_IRQ, &timer_action);
584 #ifdef CONFIG_SMP
585 irq_set_handler(IPI_IRQ, handle_percpu_irq);
586 setup_irq(IPI_IRQ, &ipi_action);
587 #endif
588 }
589
init_IRQ(void)590 void __init init_IRQ(void)
591 {
592 local_irq_disable(); /* PARANOID - should already be disabled */
593 mtctl(~0UL, 23); /* EIRR : clear all pending external intr */
594 #ifdef CONFIG_SMP
595 if (!cpu_eiem) {
596 claim_cpu_irqs();
597 cpu_eiem = EIEM_MASK(IPI_IRQ) | EIEM_MASK(TIMER_IRQ);
598 }
599 #else
600 claim_cpu_irqs();
601 cpu_eiem = EIEM_MASK(TIMER_IRQ);
602 #endif
603 set_eiem(cpu_eiem); /* EIEM : enable all external intr */
604 }
605