summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/traps.c
blob: bc7b7be7acbe7b9858992e75fcc86309d59de79b (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
/*
 *  arch/s390/kernel/traps.c
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
 *
 *  Derived from "arch/i386/kernel/traps.c"
 *    Copyright (C) 1991, 1992 Linus Torvalds
 */

/*
 * 'Traps.c' handles hardware traps and faults after we have saved some
 * state in 'asm.s'.
 */
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/kallsyms.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/mathemu.h>
#include <asm/cpcmd.h>
#include <asm/s390_ext.h>
#include <asm/lowcore.h>
#include <asm/debug.h>

/* Called from entry.S only */
extern void handle_per_exception(struct pt_regs *regs);

typedef void pgm_check_handler_t(struct pt_regs *, long);
pgm_check_handler_t *pgm_check_table[128];

#ifdef CONFIG_SYSCTL
#ifdef CONFIG_PROCESS_DEBUG
int sysctl_userprocess_debug = 1;
#else
int sysctl_userprocess_debug = 0;
#endif
#endif

extern pgm_check_handler_t do_protection_exception;
extern pgm_check_handler_t do_dat_exception;
extern pgm_check_handler_t do_pseudo_page_fault;
#ifdef CONFIG_PFAULT
extern int pfault_init(void);
extern void pfault_fini(void);
extern void pfault_interrupt(struct pt_regs *regs, __u16 error_code);
static ext_int_info_t ext_int_pfault;
#endif
extern pgm_check_handler_t do_monitor_call;

#define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })

#ifndef CONFIG_ARCH_S390X
#define FOURLONG "%08lx %08lx %08lx %08lx\n"
static int kstack_depth_to_print = 12;
#else /* CONFIG_ARCH_S390X */
#define FOURLONG "%016lx %016lx %016lx %016lx\n"
static int kstack_depth_to_print = 20;
#endif /* CONFIG_ARCH_S390X */

/*
 * For show_trace we have tree different stack to consider:
 *   - the panic stack which is used if the kernel stack has overflown
 *   - the asynchronous interrupt stack (cpu related)
 *   - the synchronous kernel stack (process related)
 * The stack trace can start at any of the three stack and can potentially
 * touch all of them. The order is: panic stack, async stack, sync stack.
 */
static unsigned long
__show_trace(unsigned long sp, unsigned long low, unsigned long high)
{
	struct stack_frame *sf;
	struct pt_regs *regs;

	while (1) {
		sp = sp & PSW_ADDR_INSN;
		if (sp < low || sp > high - sizeof(*sf))
			return sp;
		sf = (struct stack_frame *) sp;
		printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
		print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
		/* Follow the backchain. */
		while (1) {
			low = sp;
			sp = sf->back_chain & PSW_ADDR_INSN;
			if (!sp)
				break;
			if (sp <= low || sp > high - sizeof(*sf))
				return sp;
			sf = (struct stack_frame *) sp;
			printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
			print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
		}
		/* Zero backchain detected, check for interrupt frame. */
		sp = (unsigned long) (sf + 1);
		if (sp <= low || sp > high - sizeof(*regs))
			return sp;
		regs = (struct pt_regs *) sp;
		printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
		print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
		low = sp;
		sp = regs->gprs[15];
	}
}

void show_trace(struct task_struct *task, unsigned long * stack)
{
	register unsigned long __r15 asm ("15");
	unsigned long sp;

	sp = (unsigned long) stack;
	if (!sp)
		sp = task ? task->thread.ksp : __r15;
	printk("Call Trace:\n");
#ifdef CONFIG_CHECK_STACK
	sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
			  S390_lowcore.panic_stack);
#endif
	sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
			  S390_lowcore.async_stack);
	if (task)
		__show_trace(sp, (unsigned long) task->thread_info,
			     (unsigned long) task->thread_info + THREAD_SIZE);
	else
		__show_trace(sp, S390_lowcore.thread_info,
			     S390_lowcore.thread_info + THREAD_SIZE);
	printk("\n");
}

void show_stack(struct task_struct *task, unsigned long *sp)
{
	register unsigned long * __r15 asm ("15");
	unsigned long *stack;
	int i;

	// debugging aid: "show_stack(NULL);" prints the
	// back trace for this cpu.

	if (!sp)
		sp = task ? (unsigned long *) task->thread.ksp : __r15;

	stack = sp;
	for (i = 0; i < kstack_depth_to_print; i++) {
		if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
			break;
		if (i && ((i * sizeof (long) % 32) == 0))
			printk("\n       ");
		printk("%p ", (void *)*stack++);
	}
	printk("\n");
	show_trace(task, sp);
}

/*
 * The architecture-independent dump_stack generator
 */
void dump_stack(void)
{
	show_stack(0, 0);
}

EXPORT_SYMBOL(dump_stack);

void show_registers(struct pt_regs *regs)
{
	mm_segment_t old_fs;
	char *mode;
	int i;

	mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
	printk("%s PSW : %p %p",
	       mode, (void *) regs->psw.mask,
	       (void *) regs->psw.addr);
	print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
	printk("%s GPRS: " FOURLONG, mode,
	       regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
	printk("           " FOURLONG,
	       regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
	printk("           " FOURLONG,
	       regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
	printk("           " FOURLONG,
	       regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);

#if 0
	/* FIXME: this isn't needed any more but it changes the ksymoops
	 * input. To remove or not to remove ... */
	save_access_regs(regs->acrs);
	printk("%s ACRS: %08x %08x %08x %08x\n", mode,
	       regs->acrs[0], regs->acrs[1], regs->acrs[2], regs->acrs[3]);
	printk("           %08x %08x %08x %08x\n",
	       regs->acrs[4], regs->acrs[5], regs->acrs[6], regs->acrs[7]);
	printk("           %08x %08x %08x %08x\n",
	       regs->acrs[8], regs->acrs[9], regs->acrs[10], regs->acrs[11]);
	printk("           %08x %08x %08x %08x\n",
	       regs->acrs[12], regs->acrs[13], regs->acrs[14], regs->acrs[15]);
#endif

	/*
	 * Print the first 20 byte of the instruction stream at the
	 * time of the fault.
	 */
	old_fs = get_fs();
	if (regs->psw.mask & PSW_MASK_PSTATE)
		set_fs(USER_DS);
	else
		set_fs(KERNEL_DS);
	printk("%s Code: ", mode);
	for (i = 0; i < 20; i++) {
		unsigned char c;
		if (__get_user(c, (char __user *)(regs->psw.addr + i))) {
			printk(" Bad PSW.");
			break;
		}
		printk("%02x ", c);
	}
	set_fs(old_fs);

	printk("\n");
}	

/* This is called from fs/proc/array.c */
char *task_show_regs(struct task_struct *task, char *buffer)
{
	struct pt_regs *regs;

	regs = __KSTK_PTREGS(task);
	buffer += sprintf(buffer, "task: %p, ksp: %p\n",
		       task, (void *)task->thread.ksp);
	buffer += sprintf(buffer, "User PSW : %p %p\n",
		       (void *) regs->psw.mask, (void *)regs->psw.addr);

	buffer += sprintf(buffer, "User GPRS: " FOURLONG,
			  regs->gprs[0], regs->gprs[1],
			  regs->gprs[2], regs->gprs[3]);
	buffer += sprintf(buffer, "           " FOURLONG,
			  regs->gprs[4], regs->gprs[5],
			  regs->gprs[6], regs->gprs[7]);
	buffer += sprintf(buffer, "           " FOURLONG,
			  regs->gprs[8], regs->gprs[9],
			  regs->gprs[10], regs->gprs[11]);
	buffer += sprintf(buffer, "           " FOURLONG,
			  regs->gprs[12], regs->gprs[13],
			  regs->gprs[14], regs->gprs[15]);
	buffer += sprintf(buffer, "User ACRS: %08x %08x %08x %08x\n",
			  task->thread.acrs[0], task->thread.acrs[1],
			  task->thread.acrs[2], task->thread.acrs[3]);
	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
			  task->thread.acrs[4], task->thread.acrs[5],
			  task->thread.acrs[6], task->thread.acrs[7]);
	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
			  task->thread.acrs[8], task->thread.acrs[9],
			  task->thread.acrs[10], task->thread.acrs[11]);
	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
			  task->thread.acrs[12], task->thread.acrs[13],
			  task->thread.acrs[14], task->thread.acrs[15]);
	return buffer;
}

DEFINE_SPINLOCK(die_lock);

void die(const char * str, struct pt_regs * regs, long err)
{
	static int die_counter;

	debug_stop_all();
	console_verbose();
	spin_lock_irq(&die_lock);
	bust_spinlocks(1);
	printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
        show_regs(regs);
	bust_spinlocks(0);
        spin_unlock_irq(&die_lock);
	if (in_interrupt())
		panic("Fatal exception in interrupt");
	if (panic_on_oops)
		panic("Fatal exception: panic_on_oops");
        do_exit(SIGSEGV);
}

static void inline
report_user_fault(long interruption_code, struct pt_regs *regs)
{
#if defined(CONFIG_SYSCTL)
	if (!sysctl_userprocess_debug)
		return;
#endif
#if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
	printk("User process fault: interruption code 0x%lX\n",
	       interruption_code);
	show_regs(regs);
#endif
}

static void inline do_trap(long interruption_code, int signr, char *str,
                           struct pt_regs *regs, siginfo_t *info)
{
	/*
	 * We got all needed information from the lowcore and can
	 * now safely switch on interrupts.
	 */
        if (regs->psw.mask & PSW_MASK_PSTATE)
		local_irq_enable();

        if (regs->psw.mask & PSW_MASK_PSTATE) {
                struct task_struct *tsk = current;

                tsk->thread.trap_no = interruption_code & 0xffff;
		force_sig_info(signr, info, tsk);
		report_user_fault(interruption_code, regs);
        } else {
                const struct exception_table_entry *fixup;
                fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
                if (fixup)
                        regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
                else
                        die(str, regs, interruption_code);
        }
}

static inline void *get_check_address(struct pt_regs *regs)
{
	return (void *)((regs->psw.addr-S390_lowcore.pgm_ilc) & PSW_ADDR_INSN);
}

void do_single_step(struct pt_regs *regs)
{
	if ((current->ptrace & PT_PTRACED) != 0)
		force_sig(SIGTRAP, current);
}

asmlinkage void
default_trap_handler(struct pt_regs * regs, long interruption_code)
{
        if (regs->psw.mask & PSW_MASK_PSTATE) {
		local_irq_enable();
		do_exit(SIGSEGV);
		report_user_fault(interruption_code, regs);
	} else
		die("Unknown program exception", regs, interruption_code);
}

#define DO_ERROR_INFO(signr, str, name, sicode, siaddr) \
asmlinkage void name(struct pt_regs * regs, long interruption_code) \
{ \
        siginfo_t info; \
        info.si_signo = signr; \
        info.si_errno = 0; \
        info.si_code = sicode; \
        info.si_addr = (void *)siaddr; \
        do_trap(interruption_code, signr, str, regs, &info); \
}

DO_ERROR_INFO(SIGILL, "addressing exception", addressing_exception,
	      ILL_ILLADR, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "execute exception", execute_exception,
	      ILL_ILLOPN, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "fixpoint divide exception", divide_exception,
	      FPE_INTDIV, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "fixpoint overflow exception", overflow_exception,
	      FPE_INTOVF, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "HFP overflow exception", hfp_overflow_exception,
	      FPE_FLTOVF, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "HFP underflow exception", hfp_underflow_exception,
	      FPE_FLTUND, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "HFP significance exception", hfp_significance_exception,
	      FPE_FLTRES, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "HFP divide exception", hfp_divide_exception,
	      FPE_FLTDIV, get_check_address(regs))
DO_ERROR_INFO(SIGFPE,  "HFP square root exception", hfp_sqrt_exception,
	      FPE_FLTINV, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "operand exception", operand_exception,
	      ILL_ILLOPN, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "privileged operation", privileged_op,
	      ILL_PRVOPC, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "special operation exception", special_op_exception,
	      ILL_ILLOPN, get_check_address(regs))
DO_ERROR_INFO(SIGILL,  "translation exception", translation_exception,
	      ILL_ILLOPN, get_check_address(regs))

static inline void
do_fp_trap(struct pt_regs *regs, void *location,
           int fpc, long interruption_code)
{
	siginfo_t si;

	si.si_signo = SIGFPE;
	si.si_errno = 0;
	si.si_addr = location;
	si.si_code = 0;
	/* FPC[2] is Data Exception Code */
	if ((fpc & 0x00000300) == 0) {
		/* bits 6 and 7 of DXC are 0 iff IEEE exception */
		if (fpc & 0x8000) /* invalid fp operation */
			si.si_code = FPE_FLTINV;
		else if (fpc & 0x4000) /* div by 0 */
			si.si_code = FPE_FLTDIV;
		else if (fpc & 0x2000) /* overflow */
			si.si_code = FPE_FLTOVF;
		else if (fpc & 0x1000) /* underflow */
			si.si_code = FPE_FLTUND;
		else if (fpc & 0x0800) /* inexact */
			si.si_code = FPE_FLTRES;
	}
	current->thread.ieee_instruction_pointer = (addr_t) location;
	do_trap(interruption_code, SIGFPE,
		"floating point exception", regs, &si);
}

asmlinkage void illegal_op(struct pt_regs * regs, long interruption_code)
{
	siginfo_t info;
        __u8 opcode[6];
	__u16 *location;
	int signal = 0;

	location = (__u16 *) get_check_address(regs);

	/*
	 * We got all needed information from the lowcore and can
	 * now safely switch on interrupts.
	 */
	if (regs->psw.mask & PSW_MASK_PSTATE)
		local_irq_enable();

	if (regs->psw.mask & PSW_MASK_PSTATE) {
		get_user(*((__u16 *) opcode), (__u16 __user *) location);
		if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
			if (current->ptrace & PT_PTRACED)
				force_sig(SIGTRAP, current);
			else
				signal = SIGILL;
#ifdef CONFIG_MATHEMU
		} else if (opcode[0] == 0xb3) {
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_b3(opcode, regs);
                } else if (opcode[0] == 0xed) {
			get_user(*((__u32 *) (opcode+2)),
				 (__u32 *)(location+1));
			signal = math_emu_ed(opcode, regs);
		} else if (*((__u16 *) opcode) == 0xb299) {
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_srnm(opcode, regs);
		} else if (*((__u16 *) opcode) == 0xb29c) {
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_stfpc(opcode, regs);
		} else if (*((__u16 *) opcode) == 0xb29d) {
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_lfpc(opcode, regs);
#endif
		} else
			signal = SIGILL;
	} else
		signal = SIGILL;

#ifdef CONFIG_MATHEMU
        if (signal == SIGFPE)
		do_fp_trap(regs, location,
                           current->thread.fp_regs.fpc, interruption_code);
        else if (signal == SIGSEGV) {
		info.si_signo = signal;
		info.si_errno = 0;
		info.si_code = SEGV_MAPERR;
		info.si_addr = (void *) location;
		do_trap(interruption_code, signal,
			"user address fault", regs, &info);
	} else
#endif
        if (signal) {
		info.si_signo = signal;
		info.si_errno = 0;
		info.si_code = ILL_ILLOPC;
		info.si_addr = (void *) location;
		do_trap(interruption_code, signal,
			"illegal operation", regs, &info);
	}
}


#ifdef CONFIG_MATHEMU
asmlinkage void 
specification_exception(struct pt_regs * regs, long interruption_code)
{
        __u8 opcode[6];
	__u16 *location = NULL;
	int signal = 0;

	location = (__u16 *) get_check_address(regs);

	/*
	 * We got all needed information from the lowcore and can
	 * now safely switch on interrupts.
	 */
        if (regs->psw.mask & PSW_MASK_PSTATE)
		local_irq_enable();

        if (regs->psw.mask & PSW_MASK_PSTATE) {
		get_user(*((__u16 *) opcode), location);
		switch (opcode[0]) {
		case 0x28: /* LDR Rx,Ry   */
			signal = math_emu_ldr(opcode);
			break;
		case 0x38: /* LER Rx,Ry   */
			signal = math_emu_ler(opcode);
			break;
		case 0x60: /* STD R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_std(opcode, regs);
			break;
		case 0x68: /* LD R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_ld(opcode, regs);
			break;
		case 0x70: /* STE R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_ste(opcode, regs);
			break;
		case 0x78: /* LE R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_le(opcode, regs);
			break;
		default:
			signal = SIGILL;
			break;
                }
        } else
		signal = SIGILL;

        if (signal == SIGFPE)
		do_fp_trap(regs, location,
                           current->thread.fp_regs.fpc, interruption_code);
        else if (signal) {
		siginfo_t info;
		info.si_signo = signal;
		info.si_errno = 0;
		info.si_code = ILL_ILLOPN;
		info.si_addr = location;
		do_trap(interruption_code, signal, 
			"specification exception", regs, &info);
	}
}
#else
DO_ERROR_INFO(SIGILL, "specification exception", specification_exception,
	      ILL_ILLOPN, get_check_address(regs));
#endif

asmlinkage void data_exception(struct pt_regs * regs, long interruption_code)
{
	__u16 *location;
	int signal = 0;

	location = (__u16 *) get_check_address(regs);

	/*
	 * We got all needed information from the lowcore and can
	 * now safely switch on interrupts.
	 */
	if (regs->psw.mask & PSW_MASK_PSTATE)
		local_irq_enable();

	if (MACHINE_HAS_IEEE)
		__asm__ volatile ("stfpc %0\n\t" 
				  : "=m" (current->thread.fp_regs.fpc));

#ifdef CONFIG_MATHEMU
        else if (regs->psw.mask & PSW_MASK_PSTATE) {
        	__u8 opcode[6];
		get_user(*((__u16 *) opcode), location);
		switch (opcode[0]) {
		case 0x28: /* LDR Rx,Ry   */
			signal = math_emu_ldr(opcode);
			break;
		case 0x38: /* LER Rx,Ry   */
			signal = math_emu_ler(opcode);
			break;
		case 0x60: /* STD R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_std(opcode, regs);
			break;
		case 0x68: /* LD R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_ld(opcode, regs);
			break;
		case 0x70: /* STE R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_ste(opcode, regs);
			break;
		case 0x78: /* LE R,D(X,B) */
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_le(opcode, regs);
			break;
		case 0xb3:
			get_user(*((__u16 *) (opcode+2)), location+1);
			signal = math_emu_b3(opcode, regs);
			break;
                case 0xed:
			get_user(*((__u32 *) (opcode+2)),
				 (__u32 *)(location+1));
			signal = math_emu_ed(opcode, regs);
			break;
	        case 0xb2:
			if (opcode[1] == 0x99) {
				get_user(*((__u16 *) (opcode+2)), location+1);
				signal = math_emu_srnm(opcode, regs);
			} else if (opcode[1] == 0x9c) {
				get_user(*((__u16 *) (opcode+2)), location+1);
				signal = math_emu_stfpc(opcode, regs);
			} else if (opcode[1] == 0x9d) {
				get_user(*((__u16 *) (opcode+2)), location+1);
				signal = math_emu_lfpc(opcode, regs);
			} else
				signal = SIGILL;
			break;
		default:
			signal = SIGILL;
			break;
                }
        }
#endif 
	if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
		signal = SIGFPE;
	else
		signal = SIGILL;
        if (signal == SIGFPE)
		do_fp_trap(regs, location,
                           current->thread.fp_regs.fpc, interruption_code);
        else if (signal) {
		siginfo_t info;
		info.si_signo = signal;
		info.si_errno = 0;
		info.si_code = ILL_ILLOPN;
		info.si_addr = location;
		do_trap(interruption_code, signal, 
			"data exception", regs, &info);
	}
}

asmlinkage void space_switch_exception(struct pt_regs * regs, long int_code)
{
        siginfo_t info;

	/* Set user psw back to home space mode. */
	if (regs->psw.mask & PSW_MASK_PSTATE)
		regs->psw.mask |= PSW_ASC_HOME;
	/* Send SIGILL. */
        info.si_signo = SIGILL;
        info.si_errno = 0;
        info.si_code = ILL_PRVOPC;
        info.si_addr = get_check_address(regs);
        do_trap(int_code, SIGILL, "space switch event", regs, &info);
}

asmlinkage void kernel_stack_overflow(struct pt_regs * regs)
{
	bust_spinlocks(1);
	printk("Kernel stack overflow.\n");
	show_regs(regs);
	bust_spinlocks(0);
	panic("Corrupt kernel stack, can't continue.");
}


/* init is done in lowcore.S and head.S */

void __init trap_init(void)
{
        int i;

        for (i = 0; i < 128; i++)
          pgm_check_table[i] = &default_trap_handler;
        pgm_check_table[1] = &illegal_op;
        pgm_check_table[2] = &privileged_op;
        pgm_check_table[3] = &execute_exception;
        pgm_check_table[4] = &do_protection_exception;
        pgm_check_table[5] = &addressing_exception;
        pgm_check_table[6] = &specification_exception;
        pgm_check_table[7] = &data_exception;
        pgm_check_table[8] = &overflow_exception;
        pgm_check_table[9] = &divide_exception;
        pgm_check_table[0x0A] = &overflow_exception;
        pgm_check_table[0x0B] = &divide_exception;
        pgm_check_table[0x0C] = &hfp_overflow_exception;
        pgm_check_table[0x0D] = &hfp_underflow_exception;
        pgm_check_table[0x0E] = &hfp_significance_exception;
        pgm_check_table[0x0F] = &hfp_divide_exception;
        pgm_check_table[0x10] = &do_dat_exception;
        pgm_check_table[0x11] = &do_dat_exception;
        pgm_check_table[0x12] = &translation_exception;
        pgm_check_table[0x13] = &special_op_exception;
#ifndef CONFIG_ARCH_S390X
 	pgm_check_table[0x14] = &do_pseudo_page_fault;
#else /* CONFIG_ARCH_S390X */
        pgm_check_table[0x38] = &do_dat_exception;
	pgm_check_table[0x39] = &do_dat_exception;
	pgm_check_table[0x3A] = &do_dat_exception;
        pgm_check_table[0x3B] = &do_dat_exception;
#endif /* CONFIG_ARCH_S390X */
        pgm_check_table[0x15] = &operand_exception;
        pgm_check_table[0x1C] = &space_switch_exception;
        pgm_check_table[0x1D] = &hfp_sqrt_exception;
	pgm_check_table[0x40] = &do_monitor_call;

	if (MACHINE_IS_VM) {
		/*
		 * First try to get pfault pseudo page faults going.
		 * If this isn't available turn on pagex page faults.
		 */
#ifdef CONFIG_PFAULT
		/* request the 0x2603 external interrupt */
		if (register_early_external_interrupt(0x2603, pfault_interrupt,
						      &ext_int_pfault) != 0)
			panic("Couldn't request external interrupt 0x2603");

		if (pfault_init() == 0) 
			return;
		
		/* Tough luck, no pfault. */
		unregister_early_external_interrupt(0x2603, pfault_interrupt,
						    &ext_int_pfault);
#endif
#ifndef CONFIG_ARCH_S390X
		cpcmd("SET PAGEX ON", NULL, 0, NULL);
#endif
	}
}