xref: /linux/arch/s390/kernel/traps.c (revision ec2212088c42ff7d1362629ec26dda4f3e8bdad3)
1 /*
2  *  arch/s390/kernel/traps.c
3  *
4  *  S390 version
5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
8  *
9  *  Derived from "arch/i386/kernel/traps.c"
10  *    Copyright (C) 1991, 1992 Linus Torvalds
11  */
12 
13 /*
14  * 'Traps.c' handles hardware traps and faults after we have saved some
15  * state in 'asm.s'.
16  */
17 #include <linux/sched.h>
18 #include <linux/kernel.h>
19 #include <linux/string.h>
20 #include <linux/errno.h>
21 #include <linux/ptrace.h>
22 #include <linux/timer.h>
23 #include <linux/mm.h>
24 #include <linux/smp.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/seq_file.h>
28 #include <linux/delay.h>
29 #include <linux/module.h>
30 #include <linux/kdebug.h>
31 #include <linux/kallsyms.h>
32 #include <linux/reboot.h>
33 #include <linux/kprobes.h>
34 #include <linux/bug.h>
35 #include <linux/utsname.h>
36 #include <asm/system.h>
37 #include <asm/uaccess.h>
38 #include <asm/io.h>
39 #include <linux/atomic.h>
40 #include <asm/mathemu.h>
41 #include <asm/cpcmd.h>
42 #include <asm/lowcore.h>
43 #include <asm/debug.h>
44 #include <asm/ipl.h>
45 #include "entry.h"
46 
47 void (*pgm_check_table[128])(struct pt_regs *regs);
48 
49 int show_unhandled_signals = 1;
50 
51 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
52 
53 #ifndef CONFIG_64BIT
54 #define LONG "%08lx "
55 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
56 static int kstack_depth_to_print = 12;
57 #else /* CONFIG_64BIT */
58 #define LONG "%016lx "
59 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
60 static int kstack_depth_to_print = 20;
61 #endif /* CONFIG_64BIT */
62 
63 /*
64  * For show_trace we have tree different stack to consider:
65  *   - the panic stack which is used if the kernel stack has overflown
66  *   - the asynchronous interrupt stack (cpu related)
67  *   - the synchronous kernel stack (process related)
68  * The stack trace can start at any of the three stack and can potentially
69  * touch all of them. The order is: panic stack, async stack, sync stack.
70  */
71 static unsigned long
72 __show_trace(unsigned long sp, unsigned long low, unsigned long high)
73 {
74 	struct stack_frame *sf;
75 	struct pt_regs *regs;
76 
77 	while (1) {
78 		sp = sp & PSW_ADDR_INSN;
79 		if (sp < low || sp > high - sizeof(*sf))
80 			return sp;
81 		sf = (struct stack_frame *) sp;
82 		printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
83 		print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
84 		/* Follow the backchain. */
85 		while (1) {
86 			low = sp;
87 			sp = sf->back_chain & PSW_ADDR_INSN;
88 			if (!sp)
89 				break;
90 			if (sp <= low || sp > high - sizeof(*sf))
91 				return sp;
92 			sf = (struct stack_frame *) sp;
93 			printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
94 			print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
95 		}
96 		/* Zero backchain detected, check for interrupt frame. */
97 		sp = (unsigned long) (sf + 1);
98 		if (sp <= low || sp > high - sizeof(*regs))
99 			return sp;
100 		regs = (struct pt_regs *) sp;
101 		printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
102 		print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
103 		low = sp;
104 		sp = regs->gprs[15];
105 	}
106 }
107 
108 static void show_trace(struct task_struct *task, unsigned long *stack)
109 {
110 	register unsigned long __r15 asm ("15");
111 	unsigned long sp;
112 
113 	sp = (unsigned long) stack;
114 	if (!sp)
115 		sp = task ? task->thread.ksp : __r15;
116 	printk("Call Trace:\n");
117 #ifdef CONFIG_CHECK_STACK
118 	sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
119 			  S390_lowcore.panic_stack);
120 #endif
121 	sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
122 			  S390_lowcore.async_stack);
123 	if (task)
124 		__show_trace(sp, (unsigned long) task_stack_page(task),
125 			     (unsigned long) task_stack_page(task) + THREAD_SIZE);
126 	else
127 		__show_trace(sp, S390_lowcore.thread_info,
128 			     S390_lowcore.thread_info + THREAD_SIZE);
129 	if (!task)
130 		task = current;
131 	debug_show_held_locks(task);
132 }
133 
134 void show_stack(struct task_struct *task, unsigned long *sp)
135 {
136 	register unsigned long * __r15 asm ("15");
137 	unsigned long *stack;
138 	int i;
139 
140 	if (!sp)
141 		stack = task ? (unsigned long *) task->thread.ksp : __r15;
142 	else
143 		stack = sp;
144 
145 	for (i = 0; i < kstack_depth_to_print; i++) {
146 		if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
147 			break;
148 		if ((i * sizeof(long) % 32) == 0)
149 			printk("%s       ", i == 0 ? "" : "\n");
150 		printk(LONG, *stack++);
151 	}
152 	printk("\n");
153 	show_trace(task, sp);
154 }
155 
156 static void show_last_breaking_event(struct pt_regs *regs)
157 {
158 #ifdef CONFIG_64BIT
159 	printk("Last Breaking-Event-Address:\n");
160 	printk(" [<%016lx>] ", regs->args[0] & PSW_ADDR_INSN);
161 	print_symbol("%s\n", regs->args[0] & PSW_ADDR_INSN);
162 #endif
163 }
164 
165 /*
166  * The architecture-independent dump_stack generator
167  */
168 void dump_stack(void)
169 {
170 	printk("CPU: %d %s %s %.*s\n",
171 	       task_thread_info(current)->cpu, print_tainted(),
172 	       init_utsname()->release,
173 	       (int)strcspn(init_utsname()->version, " "),
174 	       init_utsname()->version);
175 	printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
176 	       current->comm, current->pid, current,
177 	       (void *) current->thread.ksp);
178 	show_stack(NULL, NULL);
179 }
180 EXPORT_SYMBOL(dump_stack);
181 
182 static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
183 {
184 	return (regs->psw.mask & bits) / ((~bits + 1) & bits);
185 }
186 
187 void show_registers(struct pt_regs *regs)
188 {
189 	char *mode;
190 
191 	mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
192 	printk("%s PSW : %p %p",
193 	       mode, (void *) regs->psw.mask,
194 	       (void *) regs->psw.addr);
195 	print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
196 	printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
197 	       "P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
198 	       mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
199 	       mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
200 	       mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
201 	       mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
202 	       mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
203 #ifdef CONFIG_64BIT
204 	printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
205 #endif
206 	printk("\n%s GPRS: " FOURLONG, mode,
207 	       regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
208 	printk("           " FOURLONG,
209 	       regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
210 	printk("           " FOURLONG,
211 	       regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
212 	printk("           " FOURLONG,
213 	       regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
214 
215 	show_code(regs);
216 }
217 
218 void show_regs(struct pt_regs *regs)
219 {
220 	print_modules();
221 	printk("CPU: %d %s %s %.*s\n",
222 	       task_thread_info(current)->cpu, print_tainted(),
223 	       init_utsname()->release,
224 	       (int)strcspn(init_utsname()->version, " "),
225 	       init_utsname()->version);
226 	printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
227 	       current->comm, current->pid, current,
228 	       (void *) current->thread.ksp);
229 	show_registers(regs);
230 	/* Show stack backtrace if pt_regs is from kernel mode */
231 	if (!(regs->psw.mask & PSW_MASK_PSTATE))
232 		show_trace(NULL, (unsigned long *) regs->gprs[15]);
233 	show_last_breaking_event(regs);
234 }
235 
236 static DEFINE_SPINLOCK(die_lock);
237 
238 void die(struct pt_regs *regs, const char *str)
239 {
240 	static int die_counter;
241 
242 	oops_enter();
243 	lgr_info_log();
244 	debug_stop_all();
245 	console_verbose();
246 	spin_lock_irq(&die_lock);
247 	bust_spinlocks(1);
248 	printk("%s: %04x [#%d] ", str, regs->int_code & 0xffff, ++die_counter);
249 #ifdef CONFIG_PREEMPT
250 	printk("PREEMPT ");
251 #endif
252 #ifdef CONFIG_SMP
253 	printk("SMP ");
254 #endif
255 #ifdef CONFIG_DEBUG_PAGEALLOC
256 	printk("DEBUG_PAGEALLOC");
257 #endif
258 	printk("\n");
259 	notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
260 	show_regs(regs);
261 	bust_spinlocks(0);
262 	add_taint(TAINT_DIE);
263 	spin_unlock_irq(&die_lock);
264 	if (in_interrupt())
265 		panic("Fatal exception in interrupt");
266 	if (panic_on_oops)
267 		panic("Fatal exception: panic_on_oops");
268 	oops_exit();
269 	do_exit(SIGSEGV);
270 }
271 
272 static inline void report_user_fault(struct pt_regs *regs, int signr)
273 {
274 	if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
275 		return;
276 	if (!unhandled_signal(current, signr))
277 		return;
278 	if (!printk_ratelimit())
279 		return;
280 	printk("User process fault: interruption code 0x%X ", regs->int_code);
281 	print_vma_addr("in ", regs->psw.addr & PSW_ADDR_INSN);
282 	printk("\n");
283 	show_regs(regs);
284 }
285 
286 int is_valid_bugaddr(unsigned long addr)
287 {
288 	return 1;
289 }
290 
291 static inline void __user *get_psw_address(struct pt_regs *regs)
292 {
293 	return (void __user *)
294 		((regs->psw.addr - (regs->int_code >> 16)) & PSW_ADDR_INSN);
295 }
296 
297 static void __kprobes do_trap(struct pt_regs *regs,
298 			      int si_signo, int si_code, char *str)
299 {
300 	siginfo_t info;
301 
302 	if (notify_die(DIE_TRAP, str, regs, 0,
303 		       regs->int_code, si_signo) == NOTIFY_STOP)
304 		return;
305 
306         if (regs->psw.mask & PSW_MASK_PSTATE) {
307 		info.si_signo = si_signo;
308 		info.si_errno = 0;
309 		info.si_code = si_code;
310 		info.si_addr = get_psw_address(regs);
311 		force_sig_info(si_signo, &info, current);
312 		report_user_fault(regs, si_signo);
313         } else {
314                 const struct exception_table_entry *fixup;
315                 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
316                 if (fixup)
317                         regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
318 		else {
319 			enum bug_trap_type btt;
320 
321 			btt = report_bug(regs->psw.addr & PSW_ADDR_INSN, regs);
322 			if (btt == BUG_TRAP_TYPE_WARN)
323 				return;
324 			die(regs, str);
325 		}
326         }
327 }
328 
329 void __kprobes do_per_trap(struct pt_regs *regs)
330 {
331 	siginfo_t info;
332 
333 	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
334 		return;
335 	if (!current->ptrace)
336 		return;
337 	info.si_signo = SIGTRAP;
338 	info.si_errno = 0;
339 	info.si_code = TRAP_HWBKPT;
340 	info.si_addr =
341 		(void __force __user *) current->thread.per_event.address;
342 	force_sig_info(SIGTRAP, &info, current);
343 }
344 
345 static void default_trap_handler(struct pt_regs *regs)
346 {
347         if (regs->psw.mask & PSW_MASK_PSTATE) {
348 		report_user_fault(regs, SIGSEGV);
349 		do_exit(SIGSEGV);
350 	} else
351 		die(regs, "Unknown program exception");
352 }
353 
354 #define DO_ERROR_INFO(name, signr, sicode, str) \
355 static void name(struct pt_regs *regs) \
356 { \
357 	do_trap(regs, signr, sicode, str); \
358 }
359 
360 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
361 	      "addressing exception")
362 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
363 	      "execute exception")
364 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
365 	      "fixpoint divide exception")
366 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
367 	      "fixpoint overflow exception")
368 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
369 	      "HFP overflow exception")
370 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
371 	      "HFP underflow exception")
372 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
373 	      "HFP significance exception")
374 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
375 	      "HFP divide exception")
376 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
377 	      "HFP square root exception")
378 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
379 	      "operand exception")
380 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
381 	      "privileged operation")
382 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
383 	      "special operation exception")
384 DO_ERROR_INFO(translation_exception, SIGILL, ILL_ILLOPN,
385 	      "translation exception")
386 
387 static inline void do_fp_trap(struct pt_regs *regs, int fpc)
388 {
389 	int si_code = 0;
390 	/* FPC[2] is Data Exception Code */
391 	if ((fpc & 0x00000300) == 0) {
392 		/* bits 6 and 7 of DXC are 0 iff IEEE exception */
393 		if (fpc & 0x8000) /* invalid fp operation */
394 			si_code = FPE_FLTINV;
395 		else if (fpc & 0x4000) /* div by 0 */
396 			si_code = FPE_FLTDIV;
397 		else if (fpc & 0x2000) /* overflow */
398 			si_code = FPE_FLTOVF;
399 		else if (fpc & 0x1000) /* underflow */
400 			si_code = FPE_FLTUND;
401 		else if (fpc & 0x0800) /* inexact */
402 			si_code = FPE_FLTRES;
403 	}
404 	do_trap(regs, SIGFPE, si_code, "floating point exception");
405 }
406 
407 static void __kprobes illegal_op(struct pt_regs *regs)
408 {
409 	siginfo_t info;
410         __u8 opcode[6];
411 	__u16 __user *location;
412 	int signal = 0;
413 
414 	location = get_psw_address(regs);
415 
416 	if (regs->psw.mask & PSW_MASK_PSTATE) {
417 		if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
418 			return;
419 		if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
420 			if (current->ptrace) {
421 				info.si_signo = SIGTRAP;
422 				info.si_errno = 0;
423 				info.si_code = TRAP_BRKPT;
424 				info.si_addr = location;
425 				force_sig_info(SIGTRAP, &info, current);
426 			} else
427 				signal = SIGILL;
428 #ifdef CONFIG_MATHEMU
429 		} else if (opcode[0] == 0xb3) {
430 			if (get_user(*((__u16 *) (opcode+2)), location+1))
431 				return;
432 			signal = math_emu_b3(opcode, regs);
433                 } else if (opcode[0] == 0xed) {
434 			if (get_user(*((__u32 *) (opcode+2)),
435 				     (__u32 __user *)(location+1)))
436 				return;
437 			signal = math_emu_ed(opcode, regs);
438 		} else if (*((__u16 *) opcode) == 0xb299) {
439 			if (get_user(*((__u16 *) (opcode+2)), location+1))
440 				return;
441 			signal = math_emu_srnm(opcode, regs);
442 		} else if (*((__u16 *) opcode) == 0xb29c) {
443 			if (get_user(*((__u16 *) (opcode+2)), location+1))
444 				return;
445 			signal = math_emu_stfpc(opcode, regs);
446 		} else if (*((__u16 *) opcode) == 0xb29d) {
447 			if (get_user(*((__u16 *) (opcode+2)), location+1))
448 				return;
449 			signal = math_emu_lfpc(opcode, regs);
450 #endif
451 		} else
452 			signal = SIGILL;
453 	} else {
454 		/*
455 		 * If we get an illegal op in kernel mode, send it through the
456 		 * kprobes notifier. If kprobes doesn't pick it up, SIGILL
457 		 */
458 		if (notify_die(DIE_BPT, "bpt", regs, 0,
459 			       3, SIGTRAP) != NOTIFY_STOP)
460 			signal = SIGILL;
461 	}
462 
463 #ifdef CONFIG_MATHEMU
464         if (signal == SIGFPE)
465 		do_fp_trap(regs, current->thread.fp_regs.fpc);
466 	else if (signal == SIGSEGV)
467 		do_trap(regs, signal, SEGV_MAPERR, "user address fault");
468 	else
469 #endif
470 	if (signal)
471 		do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
472 }
473 
474 
475 #ifdef CONFIG_MATHEMU
476 void specification_exception(struct pt_regs *regs)
477 {
478         __u8 opcode[6];
479 	__u16 __user *location = NULL;
480 	int signal = 0;
481 
482 	location = (__u16 __user *) get_psw_address(regs);
483 
484         if (regs->psw.mask & PSW_MASK_PSTATE) {
485 		get_user(*((__u16 *) opcode), location);
486 		switch (opcode[0]) {
487 		case 0x28: /* LDR Rx,Ry   */
488 			signal = math_emu_ldr(opcode);
489 			break;
490 		case 0x38: /* LER Rx,Ry   */
491 			signal = math_emu_ler(opcode);
492 			break;
493 		case 0x60: /* STD R,D(X,B) */
494 			get_user(*((__u16 *) (opcode+2)), location+1);
495 			signal = math_emu_std(opcode, regs);
496 			break;
497 		case 0x68: /* LD R,D(X,B) */
498 			get_user(*((__u16 *) (opcode+2)), location+1);
499 			signal = math_emu_ld(opcode, regs);
500 			break;
501 		case 0x70: /* STE R,D(X,B) */
502 			get_user(*((__u16 *) (opcode+2)), location+1);
503 			signal = math_emu_ste(opcode, regs);
504 			break;
505 		case 0x78: /* LE R,D(X,B) */
506 			get_user(*((__u16 *) (opcode+2)), location+1);
507 			signal = math_emu_le(opcode, regs);
508 			break;
509 		default:
510 			signal = SIGILL;
511 			break;
512                 }
513         } else
514 		signal = SIGILL;
515 
516         if (signal == SIGFPE)
517 		do_fp_trap(regs, current->thread.fp_regs.fpc);
518 	else if (signal)
519 		do_trap(regs, signal, ILL_ILLOPN, "specification exception");
520 }
521 #else
522 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
523 	      "specification exception");
524 #endif
525 
526 static void data_exception(struct pt_regs *regs)
527 {
528 	__u16 __user *location;
529 	int signal = 0;
530 
531 	location = get_psw_address(regs);
532 
533 	if (MACHINE_HAS_IEEE)
534 		asm volatile("stfpc %0" : "=m" (current->thread.fp_regs.fpc));
535 
536 #ifdef CONFIG_MATHEMU
537         else if (regs->psw.mask & PSW_MASK_PSTATE) {
538         	__u8 opcode[6];
539 		get_user(*((__u16 *) opcode), location);
540 		switch (opcode[0]) {
541 		case 0x28: /* LDR Rx,Ry   */
542 			signal = math_emu_ldr(opcode);
543 			break;
544 		case 0x38: /* LER Rx,Ry   */
545 			signal = math_emu_ler(opcode);
546 			break;
547 		case 0x60: /* STD R,D(X,B) */
548 			get_user(*((__u16 *) (opcode+2)), location+1);
549 			signal = math_emu_std(opcode, regs);
550 			break;
551 		case 0x68: /* LD R,D(X,B) */
552 			get_user(*((__u16 *) (opcode+2)), location+1);
553 			signal = math_emu_ld(opcode, regs);
554 			break;
555 		case 0x70: /* STE R,D(X,B) */
556 			get_user(*((__u16 *) (opcode+2)), location+1);
557 			signal = math_emu_ste(opcode, regs);
558 			break;
559 		case 0x78: /* LE R,D(X,B) */
560 			get_user(*((__u16 *) (opcode+2)), location+1);
561 			signal = math_emu_le(opcode, regs);
562 			break;
563 		case 0xb3:
564 			get_user(*((__u16 *) (opcode+2)), location+1);
565 			signal = math_emu_b3(opcode, regs);
566 			break;
567                 case 0xed:
568 			get_user(*((__u32 *) (opcode+2)),
569 				 (__u32 __user *)(location+1));
570 			signal = math_emu_ed(opcode, regs);
571 			break;
572 	        case 0xb2:
573 			if (opcode[1] == 0x99) {
574 				get_user(*((__u16 *) (opcode+2)), location+1);
575 				signal = math_emu_srnm(opcode, regs);
576 			} else if (opcode[1] == 0x9c) {
577 				get_user(*((__u16 *) (opcode+2)), location+1);
578 				signal = math_emu_stfpc(opcode, regs);
579 			} else if (opcode[1] == 0x9d) {
580 				get_user(*((__u16 *) (opcode+2)), location+1);
581 				signal = math_emu_lfpc(opcode, regs);
582 			} else
583 				signal = SIGILL;
584 			break;
585 		default:
586 			signal = SIGILL;
587 			break;
588                 }
589         }
590 #endif
591 	if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
592 		signal = SIGFPE;
593 	else
594 		signal = SIGILL;
595         if (signal == SIGFPE)
596 		do_fp_trap(regs, current->thread.fp_regs.fpc);
597 	else if (signal)
598 		do_trap(regs, signal, ILL_ILLOPN, "data exception");
599 }
600 
601 static void space_switch_exception(struct pt_regs *regs)
602 {
603 	/* Set user psw back to home space mode. */
604 	if (regs->psw.mask & PSW_MASK_PSTATE)
605 		regs->psw.mask |= PSW_ASC_HOME;
606 	/* Send SIGILL. */
607 	do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
608 }
609 
610 void __kprobes kernel_stack_overflow(struct pt_regs * regs)
611 {
612 	bust_spinlocks(1);
613 	printk("Kernel stack overflow.\n");
614 	show_regs(regs);
615 	bust_spinlocks(0);
616 	panic("Corrupt kernel stack, can't continue.");
617 }
618 
619 /* init is done in lowcore.S and head.S */
620 
621 void __init trap_init(void)
622 {
623         int i;
624 
625         for (i = 0; i < 128; i++)
626           pgm_check_table[i] = &default_trap_handler;
627         pgm_check_table[1] = &illegal_op;
628         pgm_check_table[2] = &privileged_op;
629         pgm_check_table[3] = &execute_exception;
630         pgm_check_table[4] = &do_protection_exception;
631         pgm_check_table[5] = &addressing_exception;
632         pgm_check_table[6] = &specification_exception;
633         pgm_check_table[7] = &data_exception;
634         pgm_check_table[8] = &overflow_exception;
635         pgm_check_table[9] = &divide_exception;
636         pgm_check_table[0x0A] = &overflow_exception;
637         pgm_check_table[0x0B] = &divide_exception;
638         pgm_check_table[0x0C] = &hfp_overflow_exception;
639         pgm_check_table[0x0D] = &hfp_underflow_exception;
640         pgm_check_table[0x0E] = &hfp_significance_exception;
641         pgm_check_table[0x0F] = &hfp_divide_exception;
642         pgm_check_table[0x10] = &do_dat_exception;
643         pgm_check_table[0x11] = &do_dat_exception;
644         pgm_check_table[0x12] = &translation_exception;
645         pgm_check_table[0x13] = &special_op_exception;
646 #ifdef CONFIG_64BIT
647 	pgm_check_table[0x38] = &do_asce_exception;
648 	pgm_check_table[0x39] = &do_dat_exception;
649 	pgm_check_table[0x3A] = &do_dat_exception;
650         pgm_check_table[0x3B] = &do_dat_exception;
651 #endif /* CONFIG_64BIT */
652         pgm_check_table[0x15] = &operand_exception;
653         pgm_check_table[0x1C] = &space_switch_exception;
654         pgm_check_table[0x1D] = &hfp_sqrt_exception;
655 	/* Enable machine checks early. */
656 	local_mcck_enable();
657 }
658