summaryrefslogtreecommitdiff
path: root/arch/parisc/kernel/traps.c
blob: 43875c289723ea9f6669e5e5eb67d59ac6f64d12 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/arch/parisc/traps.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 1999, 2000  Philipp Rumpf <prumpf@tux.org>
 */

/*
 * 'Traps.c' handles hardware traps and faults after we have saved some
 * state in 'asm.s'.
 */

#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/console.h>
#include <linux/bug.h>
#include <linux/ratelimit.h>
#include <linux/uaccess.h>
#include <linux/kdebug.h>

#include <asm/assembly.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/traps.h>
#include <asm/unaligned.h>
#include <linux/atomic.h>
#include <asm/smp.h>
#include <asm/pdc.h>
#include <asm/pdc_chassis.h>
#include <asm/unwind.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
#include <linux/kgdb.h>
#include <linux/kprobes.h>

#include "../math-emu/math-emu.h"	/* for handle_fpe() */

static void parisc_show_stack(struct task_struct *task,
	struct pt_regs *regs, const char *loglvl);

static int printbinary(char *buf, unsigned long x, int nbits)
{
	unsigned long mask = 1UL << (nbits - 1);
	while (mask != 0) {
		*buf++ = (mask & x ? '1' : '0');
		mask >>= 1;
	}
	*buf = '\0';

	return nbits;
}

#ifdef CONFIG_64BIT
#define RFMT "%016lx"
#else
#define RFMT "%08lx"
#endif
#define FFMT "%016llx"	/* fpregs are 64-bit always */

#define PRINTREGS(lvl,r,f,fmt,x)	\
	printk("%s%s%02d-%02d  " fmt " " fmt " " fmt " " fmt "\n",	\
		lvl, f, (x), (x+3), (r)[(x)+0], (r)[(x)+1],		\
		(r)[(x)+2], (r)[(x)+3])

static void print_gr(const char *level, struct pt_regs *regs)
{
	int i;
	char buf[64];

	printk("%s\n", level);
	printk("%s     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI\n", level);
	printbinary(buf, regs->gr[0], 32);
	printk("%sPSW: %s %s\n", level, buf, print_tainted());

	for (i = 0; i < 32; i += 4)
		PRINTREGS(level, regs->gr, "r", RFMT, i);
}

static void print_fr(const char *level, struct pt_regs *regs)
{
	int i;
	char buf[64];
	struct { u32 sw[2]; } s;

	/* FR are 64bit everywhere. Need to use asm to get the content
	 * of fpsr/fper1, and we assume that we won't have a FP Identify
	 * in our way, otherwise we're screwed.
	 * The fldd is used to restore the T-bit if there was one, as the
	 * store clears it anyway.
	 * PA2.0 book says "thou shall not use fstw on FPSR/FPERs" - T-Bone */
	asm volatile ("fstd %%fr0,0(%1)	\n\t"
		      "fldd 0(%1),%%fr0	\n\t"
		      : "=m" (s) : "r" (&s) : "r0");

	printk("%s\n", level);
	printk("%s      VZOUICununcqcqcqcqcqcrmunTDVZOUI\n", level);
	printbinary(buf, s.sw[0], 32);
	printk("%sFPSR: %s\n", level, buf);
	printk("%sFPER1: %08x\n", level, s.sw[1]);

	/* here we'll print fr0 again, tho it'll be meaningless */
	for (i = 0; i < 32; i += 4)
		PRINTREGS(level, regs->fr, "fr", FFMT, i);
}

void show_regs(struct pt_regs *regs)
{
	int i, user;
	const char *level;
	unsigned long cr30, cr31;

	user = user_mode(regs);
	level = user ? KERN_DEBUG : KERN_CRIT;

	show_regs_print_info(level);

	print_gr(level, regs);

	for (i = 0; i < 8; i += 4)
		PRINTREGS(level, regs->sr, "sr", RFMT, i);

	if (user)
		print_fr(level, regs);

	cr30 = mfctl(30);
	cr31 = mfctl(31);
	printk("%s\n", level);
	printk("%sIASQ: " RFMT " " RFMT " IAOQ: " RFMT " " RFMT "\n",
	       level, regs->iasq[0], regs->iasq[1], regs->iaoq[0], regs->iaoq[1]);
	printk("%s IIR: %08lx    ISR: " RFMT "  IOR: " RFMT "\n",
	       level, regs->iir, regs->isr, regs->ior);
	printk("%s CPU: %8d   CR30: " RFMT " CR31: " RFMT "\n",
	       level, current_thread_info()->cpu, cr30, cr31);
	printk("%s ORIG_R28: " RFMT "\n", level, regs->orig_r28);

	if (user) {
		printk("%s IAOQ[0]: " RFMT "\n", level, regs->iaoq[0]);
		printk("%s IAOQ[1]: " RFMT "\n", level, regs->iaoq[1]);
		printk("%s RP(r2): " RFMT "\n", level, regs->gr[2]);
	} else {
		printk("%s IAOQ[0]: %pS\n", level, (void *) regs->iaoq[0]);
		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);

		parisc_show_stack(current, regs, KERN_DEFAULT);
	}
}

static DEFINE_RATELIMIT_STATE(_hppa_rs,
	DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST);

#define parisc_printk_ratelimited(critical, regs, fmt, ...)	{	      \
	if ((critical || show_unhandled_signals) && __ratelimit(&_hppa_rs)) { \
		printk(fmt, ##__VA_ARGS__);				      \
		show_regs(regs);					      \
	}								      \
}


static void do_show_stack(struct unwind_frame_info *info, const char *loglvl)
{
	int i = 1;

	printk("%sBacktrace:\n", loglvl);
	while (i <= MAX_UNWIND_ENTRIES) {
		if (unwind_once(info) < 0 || info->ip == 0)
			break;

		if (__kernel_text_address(info->ip)) {
			printk("%s [<" RFMT ">] %pS\n",
				loglvl, info->ip, (void *) info->ip);
			i++;
		}
	}
	printk("%s\n", loglvl);
}

static void parisc_show_stack(struct task_struct *task,
	struct pt_regs *regs, const char *loglvl)
{
	struct unwind_frame_info info;

	unwind_frame_init_task(&info, task, regs);

	do_show_stack(&info, loglvl);
}

void show_stack(struct task_struct *t, unsigned long *sp, const char *loglvl)
{
	parisc_show_stack(t, NULL, loglvl);
}

int is_valid_bugaddr(unsigned long iaoq)
{
	return 1;
}

void die_if_kernel(char *str, struct pt_regs *regs, long err)
{
	if (user_mode(regs)) {
		if (err == 0)
			return; /* STFU */

		parisc_printk_ratelimited(1, regs,
			KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
			current->comm, task_pid_nr(current), str, err, regs->iaoq[0]);

		return;
	}

	bust_spinlocks(1);

	oops_enter();

	/* Amuse the user in a SPARC fashion */
	if (err) printk(KERN_CRIT
			"      _______________________________ \n"
			"     < Your System ate a SPARC! Gah! >\n"
			"      ------------------------------- \n"
			"             \\   ^__^\n"
			"                 (__)\\       )\\/\\\n"
			"                  U  ||----w |\n"
			"                     ||     ||\n");
	
	/* unlock the pdc lock if necessary */
	pdc_emergency_unlock();

	/* maybe the kernel hasn't booted very far yet and hasn't been able 
	 * to initialize the serial or STI console. In that case we should 
	 * re-enable the pdc console, so that the user will be able to 
	 * identify the problem. */
	if (!console_drivers)
		pdc_console_restart();
	
	if (err)
		printk(KERN_CRIT "%s (pid %d): %s (code %ld)\n",
			current->comm, task_pid_nr(current), str, err);

	/* Wot's wrong wif bein' racy? */
	if (current->thread.flags & PARISC_KERNEL_DEATH) {
		printk(KERN_CRIT "%s() recursion detected.\n", __func__);
		local_irq_enable();
		while (1);
	}
	current->thread.flags |= PARISC_KERNEL_DEATH;

	show_regs(regs);
	dump_stack();
	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);

	if (in_interrupt())
		panic("Fatal exception in interrupt");

	if (panic_on_oops)
		panic("Fatal exception");

	oops_exit();
	do_exit(SIGSEGV);
}

/* gdb uses break 4,8 */
#define GDB_BREAK_INSN 0x10004
static void handle_gdb_break(struct pt_regs *regs, int wot)
{
	force_sig_fault(SIGTRAP, wot,
			(void __user *) (regs->iaoq[0] & ~3));
}

static void handle_break(struct pt_regs *regs)
{
	unsigned iir = regs->iir;

	if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
		/* check if a BUG() or WARN() trapped here.  */
		enum bug_trap_type tt;
		tt = report_bug(regs->iaoq[0] & ~3, regs);
		if (tt == BUG_TRAP_TYPE_WARN) {
			regs->iaoq[0] += 4;
			regs->iaoq[1] += 4;
			return; /* return to next instruction when WARN_ON().  */
		}
		die_if_kernel("Unknown kernel breakpoint", regs,
			(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
	}

#ifdef CONFIG_KPROBES
	if (unlikely(iir == PARISC_KPROBES_BREAK_INSN)) {
		parisc_kprobe_break_handler(regs);
		return;
	}

#endif

#ifdef CONFIG_KGDB
	if (unlikely(iir == PARISC_KGDB_COMPILED_BREAK_INSN ||
		iir == PARISC_KGDB_BREAK_INSN)) {
		kgdb_handle_exception(9, SIGTRAP, 0, regs);
		return;
	}
#endif

	if (unlikely(iir != GDB_BREAK_INSN))
		parisc_printk_ratelimited(0, regs,
			KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
			iir & 31, (iir>>13) & ((1<<13)-1),
			task_pid_nr(current), current->comm);

	/* send standard GDB signal */
	handle_gdb_break(regs, TRAP_BRKPT);
}

static void default_trap(int code, struct pt_regs *regs)
{
	printk(KERN_ERR "Trap %d on CPU %d\n", code, smp_processor_id());
	show_regs(regs);
}

void (*cpu_lpmc) (int code, struct pt_regs *regs) __read_mostly = default_trap;


void transfer_pim_to_trap_frame(struct pt_regs *regs)
{
    register int i;
    extern unsigned int hpmc_pim_data[];
    struct pdc_hpmc_pim_11 *pim_narrow;
    struct pdc_hpmc_pim_20 *pim_wide;

    if (boot_cpu_data.cpu_type >= pcxu) {

	pim_wide = (struct pdc_hpmc_pim_20 *)hpmc_pim_data;

	/*
	 * Note: The following code will probably generate a
	 * bunch of truncation error warnings from the compiler.
	 * Could be handled with an ifdef, but perhaps there
	 * is a better way.
	 */

	regs->gr[0] = pim_wide->cr[22];

	for (i = 1; i < 32; i++)
	    regs->gr[i] = pim_wide->gr[i];

	for (i = 0; i < 32; i++)
	    regs->fr[i] = pim_wide->fr[i];

	for (i = 0; i < 8; i++)
	    regs->sr[i] = pim_wide->sr[i];

	regs->iasq[0] = pim_wide->cr[17];
	regs->iasq[1] = pim_wide->iasq_back;
	regs->iaoq[0] = pim_wide->cr[18];
	regs->iaoq[1] = pim_wide->iaoq_back;

	regs->sar  = pim_wide->cr[11];
	regs->iir  = pim_wide->cr[19];
	regs->isr  = pim_wide->cr[20];
	regs->ior  = pim_wide->cr[21];
    }
    else {
	pim_narrow = (struct pdc_hpmc_pim_11 *)hpmc_pim_data;

	regs->gr[0] = pim_narrow->cr[22];

	for (i = 1; i < 32; i++)
	    regs->gr[i] = pim_narrow->gr[i];

	for (i = 0; i < 32; i++)
	    regs->fr[i] = pim_narrow->fr[i];

	for (i = 0; i < 8; i++)
	    regs->sr[i] = pim_narrow->sr[i];

	regs->iasq[0] = pim_narrow->cr[17];
	regs->iasq[1] = pim_narrow->iasq_back;
	regs->iaoq[0] = pim_narrow->cr[18];
	regs->iaoq[1] = pim_narrow->iaoq_back;

	regs->sar  = pim_narrow->cr[11];
	regs->iir  = pim_narrow->cr[19];
	regs->isr  = pim_narrow->cr[20];
	regs->ior  = pim_narrow->cr[21];
    }

    /*
     * The following fields only have meaning if we came through
     * another path. So just zero them here.
     */

    regs->ksp = 0;
    regs->kpc = 0;
    regs->orig_r28 = 0;
}


/*
 * This routine is called as a last resort when everything else
 * has gone clearly wrong. We get called for faults in kernel space,
 * and HPMC's.
 */
void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long offset)
{
	static DEFINE_SPINLOCK(terminate_lock);

	(void)notify_die(DIE_OOPS, msg, regs, 0, code, SIGTRAP);
	bust_spinlocks(1);

	set_eiem(0);
	local_irq_disable();
	spin_lock(&terminate_lock);

	/* unlock the pdc lock if necessary */
	pdc_emergency_unlock();

	/* restart pdc console if necessary */
	if (!console_drivers)
		pdc_console_restart();

	/* Not all paths will gutter the processor... */
	switch(code){

	case 1:
		transfer_pim_to_trap_frame(regs);
		break;

	default:
		/* Fall through */
		break;

	}
	    
	{
		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
		struct unwind_frame_info info;
		unwind_frame_init(&info, current, regs);
		do_show_stack(&info, KERN_CRIT);
	}

	printk("\n");
	pr_crit("%s: Code=%d (%s) at addr " RFMT "\n",
		msg, code, trap_name(code), offset);
	show_regs(regs);

	spin_unlock(&terminate_lock);

	/* put soft power button back under hardware control;
	 * if the user had pressed it once at any time, the 
	 * system will shut down immediately right here. */
	pdc_soft_power_button(0);
	
	/* Call kernel panic() so reboot timeouts work properly 
	 * FIXME: This function should be on the list of
	 * panic notifiers, and we should call panic
	 * directly from the location that we wish. 
	 * e.g. We should not call panic from
	 * parisc_terminate, but rather the oter way around.
	 * This hack works, prints the panic message twice,
	 * and it enables reboot timers!
	 */
	panic(msg);
}

void notrace handle_interruption(int code, struct pt_regs *regs)
{
	unsigned long fault_address = 0;
	unsigned long fault_space = 0;
	int si_code;

	if (code == 1)
	    pdc_console_restart();  /* switch back to pdc if HPMC */
	else
	    local_irq_enable();

	/* Security check:
	 * If the priority level is still user, and the
	 * faulting space is not equal to the active space
	 * then the user is attempting something in a space
	 * that does not belong to them. Kill the process.
	 *
	 * This is normally the situation when the user
	 * attempts to jump into the kernel space at the
	 * wrong offset, be it at the gateway page or a
	 * random location.
	 *
	 * We cannot normally signal the process because it
	 * could *be* on the gateway page, and processes
	 * executing on the gateway page can't have signals
	 * delivered.
	 * 
	 * We merely readjust the address into the users
	 * space, at a destination address of zero, and
	 * allow processing to continue.
	 */
	if (((unsigned long)regs->iaoq[0] & 3) &&
	    ((unsigned long)regs->iasq[0] != (unsigned long)regs->sr[7])) { 
		/* Kill the user process later */
		regs->iaoq[0] = 0 | 3;
		regs->iaoq[1] = regs->iaoq[0] + 4;
		regs->iasq[0] = regs->iasq[1] = regs->sr[7];
		regs->gr[0] &= ~PSW_B;
		return;
	}
	
#if 0
	printk(KERN_CRIT "Interruption # %d\n", code);
#endif

	switch(code) {

	case  1:
		/* High-priority machine check (HPMC) */
		
		/* set up a new led state on systems shipped with a LED State panel */
		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_HPMC);

		parisc_terminate("High Priority Machine Check (HPMC)",
				regs, code, 0);
		/* NOT REACHED */
		
	case  2:
		/* Power failure interrupt */
		printk(KERN_CRIT "Power failure interrupt !\n");
		return;

	case  3:
		/* Recovery counter trap */
		regs->gr[0] &= ~PSW_R;

#ifdef CONFIG_KPROBES
		if (parisc_kprobe_ss_handler(regs))
			return;
#endif

#ifdef CONFIG_KGDB
		if (kgdb_single_step) {
			kgdb_handle_exception(0, SIGTRAP, 0, regs);
			return;
		}
#endif

		if (user_space(regs))
			handle_gdb_break(regs, TRAP_TRACE);
		/* else this must be the start of a syscall - just let it run */
		return;

	case  5:
		/* Low-priority machine check */
		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_LPMC);
		
		flush_cache_all();
		flush_tlb_all();
		cpu_lpmc(5, regs);
		return;

	case  PARISC_ITLB_TRAP:
		/* Instruction TLB miss fault/Instruction page fault */
		fault_address = regs->iaoq[0];
		fault_space   = regs->iasq[0];
		break;

	case  8:
		/* Illegal instruction trap */
		die_if_kernel("Illegal instruction", regs, code);
		si_code = ILL_ILLOPC;
		goto give_sigill;

	case  9:
		/* Break instruction trap */
		handle_break(regs);
		return;

	case 10:
		/* Privileged operation trap */
		die_if_kernel("Privileged operation", regs, code);
		si_code = ILL_PRVOPC;
		goto give_sigill;

	case 11:
		/* Privileged register trap */
		if ((regs->iir & 0xffdfffe0) == 0x034008a0) {

			/* This is a MFCTL cr26/cr27 to gr instruction.
			 * PCXS traps on this, so we need to emulate it.
			 */

			if (regs->iir & 0x00200000)
				regs->gr[regs->iir & 0x1f] = mfctl(27);
			else
				regs->gr[regs->iir & 0x1f] = mfctl(26);

			regs->iaoq[0] = regs->iaoq[1];
			regs->iaoq[1] += 4;
			regs->iasq[0] = regs->iasq[1];
			return;
		}

		die_if_kernel("Privileged register usage", regs, code);
		si_code = ILL_PRVREG;
	give_sigill:
		force_sig_fault(SIGILL, si_code,
				(void __user *) regs->iaoq[0]);
		return;

	case 12:
		/* Overflow Trap, let the userland signal handler do the cleanup */
		force_sig_fault(SIGFPE, FPE_INTOVF,
				(void __user *) regs->iaoq[0]);
		return;
		
	case 13:
		/* Conditional Trap
		   The condition succeeds in an instruction which traps
		   on condition  */
		if(user_mode(regs)){
			/* Let userspace app figure it out from the insn pointed
			 * to by si_addr.
			 */
			force_sig_fault(SIGFPE, FPE_CONDTRAP,
					(void __user *) regs->iaoq[0]);
			return;
		} 
		/* The kernel doesn't want to handle condition codes */
		break;
		
	case 14:
		/* Assist Exception Trap, i.e. floating point exception. */
		die_if_kernel("Floating point exception", regs, 0); /* quiet */
		__inc_irq_stat(irq_fpassist_count);
		handle_fpe(regs);
		return;

	case 15:
		/* Data TLB miss fault/Data page fault */
		/* Fall through */
	case 16:
		/* Non-access instruction TLB miss fault */
		/* The instruction TLB entry needed for the target address of the FIC
		   is absent, and hardware can't find it, so we get to cleanup */
		/* Fall through */
	case 17:
		/* Non-access data TLB miss fault/Non-access data page fault */
		/* FIXME: 
			 Still need to add slow path emulation code here!
			 If the insn used a non-shadow register, then the tlb
			 handlers could not have their side-effect (e.g. probe
			 writing to a target register) emulated since rfir would
			 erase the changes to said register. Instead we have to
			 setup everything, call this function we are in, and emulate
			 by hand. Technically we need to emulate:
			 fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw
		*/
		fault_address = regs->ior;
		fault_space = regs->isr;
		break;

	case 18:
		/* PCXS only -- later cpu's split this into types 26,27 & 28 */
		/* Check for unaligned access */
		if (check_unaligned(regs)) {
			handle_unaligned(regs);
			return;
		}
		/* Fall Through */
	case 26: 
		/* PCXL: Data memory access rights trap */
		fault_address = regs->ior;
		fault_space   = regs->isr;
		break;

	case 19:
		/* Data memory break trap */
		regs->gr[0] |= PSW_X; /* So we can single-step over the trap */
		/* fall thru */
	case 21:
		/* Page reference trap */
		handle_gdb_break(regs, TRAP_HWBKPT);
		return;

	case 25:
		/* Taken branch trap */
		regs->gr[0] &= ~PSW_T;
		if (user_space(regs))
			handle_gdb_break(regs, TRAP_BRANCH);
		/* else this must be the start of a syscall - just let it
		 * run.
		 */
		return;

	case  7:  
		/* Instruction access rights */
		/* PCXL: Instruction memory protection trap */

		/*
		 * This could be caused by either: 1) a process attempting
		 * to execute within a vma that does not have execute
		 * permission, or 2) an access rights violation caused by a
		 * flush only translation set up by ptep_get_and_clear().
		 * So we check the vma permissions to differentiate the two.
		 * If the vma indicates we have execute permission, then
		 * the cause is the latter one. In this case, we need to
		 * call do_page_fault() to fix the problem.
		 */

		if (user_mode(regs)) {
			struct vm_area_struct *vma;

			mmap_read_lock(current->mm);
			vma = find_vma(current->mm,regs->iaoq[0]);
			if (vma && (regs->iaoq[0] >= vma->vm_start)
				&& (vma->vm_flags & VM_EXEC)) {

				fault_address = regs->iaoq[0];
				fault_space = regs->iasq[0];

				mmap_read_unlock(current->mm);
				break; /* call do_page_fault() */
			}
			mmap_read_unlock(current->mm);
		}
		/* Fall Through */
	case 27: 
		/* Data memory protection ID trap */
		if (code == 27 && !user_mode(regs) &&
			fixup_exception(regs))
			return;

		die_if_kernel("Protection id trap", regs, code);
		force_sig_fault(SIGSEGV, SEGV_MAPERR,
				(code == 7)?
				((void __user *) regs->iaoq[0]) :
				((void __user *) regs->ior));
		return;

	case 28: 
		/* Unaligned data reference trap */
		handle_unaligned(regs);
		return;

	default:
		if (user_mode(regs)) {
			parisc_printk_ratelimited(0, regs, KERN_DEBUG
				"handle_interruption() pid=%d command='%s'\n",
				task_pid_nr(current), current->comm);
			/* SIGBUS, for lack of a better one. */
			force_sig_fault(SIGBUS, BUS_OBJERR,
					(void __user *)regs->ior);
			return;
		}
		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
		
		parisc_terminate("Unexpected interruption", regs, code, 0);
		/* NOT REACHED */
	}

	if (user_mode(regs)) {
	    if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
		parisc_printk_ratelimited(0, regs, KERN_DEBUG
				"User fault %d on space 0x%08lx, pid=%d command='%s'\n",
				code, fault_space,
				task_pid_nr(current), current->comm);
		force_sig_fault(SIGSEGV, SEGV_MAPERR,
				(void __user *)regs->ior);
		return;
	    }
	}
	else {

	    /*
	     * The kernel should never fault on its own address space,
	     * unless pagefault_disable() was called before.
	     */

	    if (fault_space == 0 && !faulthandler_disabled())
	    {
		/* Clean up and return if in exception table. */
		if (fixup_exception(regs))
			return;
		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
		parisc_terminate("Kernel Fault", regs, code, fault_address);
	    }
	}

	do_page_fault(regs, code, fault_address);
}


void __init initialize_ivt(const void *iva)
{
	extern u32 os_hpmc_size;
	extern const u32 os_hpmc[];

	int i;
	u32 check = 0;
	u32 *ivap;
	u32 *hpmcp;
	u32 length, instr;

	if (strcmp((const char *)iva, "cows can fly"))
		panic("IVT invalid");

	ivap = (u32 *)iva;

	for (i = 0; i < 8; i++)
	    *ivap++ = 0;

	/*
	 * Use PDC_INSTR firmware function to get instruction that invokes
	 * PDCE_CHECK in HPMC handler.  See programming note at page 1-31 of
	 * the PA 1.1 Firmware Architecture document.
	 */
	if (pdc_instr(&instr) == PDC_OK)
		ivap[0] = instr;

	/*
	 * Rules for the checksum of the HPMC handler:
	 * 1. The IVA does not point to PDC/PDH space (ie: the OS has installed
	 *    its own IVA).
	 * 2. The word at IVA + 32 is nonzero.
	 * 3. If Length (IVA + 60) is not zero, then Length (IVA + 60) and
	 *    Address (IVA + 56) are word-aligned.
	 * 4. The checksum of the 8 words starting at IVA + 32 plus the sum of
	 *    the Length/4 words starting at Address is zero.
	 */

	/* Setup IVA and compute checksum for HPMC handler */
	ivap[6] = (u32)__pa(os_hpmc);
	length = os_hpmc_size;
	ivap[7] = length;

	hpmcp = (u32 *)os_hpmc;

	for (i=0; i<length/4; i++)
	    check += *hpmcp++;

	for (i=0; i<8; i++)
	    check += ivap[i];

	ivap[5] = -check;
}
	

/* early_trap_init() is called before we set up kernel mappings and
 * write-protect the kernel */
void  __init early_trap_init(void)
{
	extern const void fault_vector_20;

#ifndef CONFIG_64BIT
	extern const void fault_vector_11;
	initialize_ivt(&fault_vector_11);
#endif

	initialize_ivt(&fault_vector_20);
}

void __init trap_init(void)
{
}