xref: /linux/arch/s390/kernel/traps.c (revision eb2bce7f5e7ac1ca6da434461217fadf3c688d2c)
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/smp_lock.h>
26 #include <linux/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/delay.h>
29 #include <linux/module.h>
30 #include <linux/kallsyms.h>
31 #include <linux/reboot.h>
32 #include <linux/kprobes.h>
33 #include <linux/bug.h>
34 #include <asm/system.h>
35 #include <asm/uaccess.h>
36 #include <asm/io.h>
37 #include <asm/atomic.h>
38 #include <asm/mathemu.h>
39 #include <asm/cpcmd.h>
40 #include <asm/s390_ext.h>
41 #include <asm/lowcore.h>
42 #include <asm/debug.h>
43 #include <asm/kdebug.h>
44 
45 /* Called from entry.S only */
46 extern void handle_per_exception(struct pt_regs *regs);
47 
48 typedef void pgm_check_handler_t(struct pt_regs *, long);
49 pgm_check_handler_t *pgm_check_table[128];
50 
51 #ifdef CONFIG_SYSCTL
52 #ifdef CONFIG_PROCESS_DEBUG
53 int sysctl_userprocess_debug = 1;
54 #else
55 int sysctl_userprocess_debug = 0;
56 #endif
57 #endif
58 
59 extern pgm_check_handler_t do_protection_exception;
60 extern pgm_check_handler_t do_dat_exception;
61 extern pgm_check_handler_t do_monitor_call;
62 
63 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
64 
65 #ifndef CONFIG_64BIT
66 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
67 static int kstack_depth_to_print = 12;
68 #else /* CONFIG_64BIT */
69 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
70 static int kstack_depth_to_print = 20;
71 #endif /* CONFIG_64BIT */
72 
73 ATOMIC_NOTIFIER_HEAD(s390die_chain);
74 
75 int register_die_notifier(struct notifier_block *nb)
76 {
77 	return atomic_notifier_chain_register(&s390die_chain, nb);
78 }
79 EXPORT_SYMBOL(register_die_notifier);
80 
81 int unregister_die_notifier(struct notifier_block *nb)
82 {
83 	return atomic_notifier_chain_unregister(&s390die_chain, nb);
84 }
85 EXPORT_SYMBOL(unregister_die_notifier);
86 
87 /*
88  * For show_trace we have tree different stack to consider:
89  *   - the panic stack which is used if the kernel stack has overflown
90  *   - the asynchronous interrupt stack (cpu related)
91  *   - the synchronous kernel stack (process related)
92  * The stack trace can start at any of the three stack and can potentially
93  * touch all of them. The order is: panic stack, async stack, sync stack.
94  */
95 static unsigned long
96 __show_trace(unsigned long sp, unsigned long low, unsigned long high)
97 {
98 	struct stack_frame *sf;
99 	struct pt_regs *regs;
100 
101 	while (1) {
102 		sp = sp & PSW_ADDR_INSN;
103 		if (sp < low || sp > high - sizeof(*sf))
104 			return sp;
105 		sf = (struct stack_frame *) sp;
106 		printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
107 		print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
108 		/* Follow the backchain. */
109 		while (1) {
110 			low = sp;
111 			sp = sf->back_chain & PSW_ADDR_INSN;
112 			if (!sp)
113 				break;
114 			if (sp <= low || sp > high - sizeof(*sf))
115 				return sp;
116 			sf = (struct stack_frame *) sp;
117 			printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
118 			print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
119 		}
120 		/* Zero backchain detected, check for interrupt frame. */
121 		sp = (unsigned long) (sf + 1);
122 		if (sp <= low || sp > high - sizeof(*regs))
123 			return sp;
124 		regs = (struct pt_regs *) sp;
125 		printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
126 		print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
127 		low = sp;
128 		sp = regs->gprs[15];
129 	}
130 }
131 
132 void show_trace(struct task_struct *task, unsigned long *stack)
133 {
134 	register unsigned long __r15 asm ("15");
135 	unsigned long sp;
136 
137 	sp = (unsigned long) stack;
138 	if (!sp)
139 		sp = task ? task->thread.ksp : __r15;
140 	printk("Call Trace:\n");
141 #ifdef CONFIG_CHECK_STACK
142 	sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
143 			  S390_lowcore.panic_stack);
144 #endif
145 	sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
146 			  S390_lowcore.async_stack);
147 	if (task)
148 		__show_trace(sp, (unsigned long) task_stack_page(task),
149 			     (unsigned long) task_stack_page(task) + THREAD_SIZE);
150 	else
151 		__show_trace(sp, S390_lowcore.thread_info,
152 			     S390_lowcore.thread_info + THREAD_SIZE);
153 	printk("\n");
154 	if (!task)
155 		task = current;
156 	debug_show_held_locks(task);
157 }
158 
159 void show_stack(struct task_struct *task, unsigned long *sp)
160 {
161 	register unsigned long * __r15 asm ("15");
162 	unsigned long *stack;
163 	int i;
164 
165 	if (!sp)
166 		stack = task ? (unsigned long *) task->thread.ksp : __r15;
167 	else
168 		stack = sp;
169 
170 	for (i = 0; i < kstack_depth_to_print; i++) {
171 		if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
172 			break;
173 		if (i && ((i * sizeof (long) % 32) == 0))
174 			printk("\n       ");
175 		printk("%p ", (void *)*stack++);
176 	}
177 	printk("\n");
178 	show_trace(task, sp);
179 }
180 
181 /*
182  * The architecture-independent dump_stack generator
183  */
184 void dump_stack(void)
185 {
186 	show_stack(NULL, NULL);
187 }
188 
189 EXPORT_SYMBOL(dump_stack);
190 
191 static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
192 {
193 	return (regs->psw.mask & bits) / ((~bits + 1) & bits);
194 }
195 
196 void show_registers(struct pt_regs *regs)
197 {
198 	char *mode;
199 
200 	mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
201 	printk("%s PSW : %p %p",
202 	       mode, (void *) regs->psw.mask,
203 	       (void *) regs->psw.addr);
204 	print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
205 	printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
206 	       "P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
207 	       mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
208 	       mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
209 	       mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
210 	       mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
211 	       mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
212 #ifdef CONFIG_64BIT
213 	printk(" EA:%x", mask_bits(regs, PSW_BASE_BITS));
214 #endif
215 	printk("\n%s GPRS: " FOURLONG, mode,
216 	       regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
217 	printk("           " FOURLONG,
218 	       regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
219 	printk("           " FOURLONG,
220 	       regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
221 	printk("           " FOURLONG,
222 	       regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
223 
224 	show_code(regs);
225 }
226 
227 /* This is called from fs/proc/array.c */
228 char *task_show_regs(struct task_struct *task, char *buffer)
229 {
230 	struct pt_regs *regs;
231 
232 	regs = task_pt_regs(task);
233 	buffer += sprintf(buffer, "task: %p, ksp: %p\n",
234 		       task, (void *)task->thread.ksp);
235 	buffer += sprintf(buffer, "User PSW : %p %p\n",
236 		       (void *) regs->psw.mask, (void *)regs->psw.addr);
237 
238 	buffer += sprintf(buffer, "User GPRS: " FOURLONG,
239 			  regs->gprs[0], regs->gprs[1],
240 			  regs->gprs[2], regs->gprs[3]);
241 	buffer += sprintf(buffer, "           " FOURLONG,
242 			  regs->gprs[4], regs->gprs[5],
243 			  regs->gprs[6], regs->gprs[7]);
244 	buffer += sprintf(buffer, "           " FOURLONG,
245 			  regs->gprs[8], regs->gprs[9],
246 			  regs->gprs[10], regs->gprs[11]);
247 	buffer += sprintf(buffer, "           " FOURLONG,
248 			  regs->gprs[12], regs->gprs[13],
249 			  regs->gprs[14], regs->gprs[15]);
250 	buffer += sprintf(buffer, "User ACRS: %08x %08x %08x %08x\n",
251 			  task->thread.acrs[0], task->thread.acrs[1],
252 			  task->thread.acrs[2], task->thread.acrs[3]);
253 	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
254 			  task->thread.acrs[4], task->thread.acrs[5],
255 			  task->thread.acrs[6], task->thread.acrs[7]);
256 	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
257 			  task->thread.acrs[8], task->thread.acrs[9],
258 			  task->thread.acrs[10], task->thread.acrs[11]);
259 	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
260 			  task->thread.acrs[12], task->thread.acrs[13],
261 			  task->thread.acrs[14], task->thread.acrs[15]);
262 	return buffer;
263 }
264 
265 static DEFINE_SPINLOCK(die_lock);
266 
267 void die(const char * str, struct pt_regs * regs, long err)
268 {
269 	static int die_counter;
270 
271 	debug_stop_all();
272 	console_verbose();
273 	spin_lock_irq(&die_lock);
274 	bust_spinlocks(1);
275 	printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
276         show_regs(regs);
277 	bust_spinlocks(0);
278         spin_unlock_irq(&die_lock);
279 	if (in_interrupt())
280 		panic("Fatal exception in interrupt");
281 	if (panic_on_oops)
282 		panic("Fatal exception: panic_on_oops");
283         do_exit(SIGSEGV);
284 }
285 
286 static void inline
287 report_user_fault(long interruption_code, struct pt_regs *regs)
288 {
289 #if defined(CONFIG_SYSCTL)
290 	if (!sysctl_userprocess_debug)
291 		return;
292 #endif
293 #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
294 	printk("User process fault: interruption code 0x%lX\n",
295 	       interruption_code);
296 	show_regs(regs);
297 #endif
298 }
299 
300 int is_valid_bugaddr(unsigned long addr)
301 {
302 	return 1;
303 }
304 
305 static void __kprobes inline do_trap(long interruption_code, int signr,
306 					char *str, struct pt_regs *regs,
307 					siginfo_t *info)
308 {
309 	/*
310 	 * We got all needed information from the lowcore and can
311 	 * now safely switch on interrupts.
312 	 */
313         if (regs->psw.mask & PSW_MASK_PSTATE)
314 		local_irq_enable();
315 
316 	if (notify_die(DIE_TRAP, str, regs, interruption_code,
317 				interruption_code, signr) == NOTIFY_STOP)
318 		return;
319 
320         if (regs->psw.mask & PSW_MASK_PSTATE) {
321                 struct task_struct *tsk = current;
322 
323                 tsk->thread.trap_no = interruption_code & 0xffff;
324 		force_sig_info(signr, info, tsk);
325 		report_user_fault(interruption_code, regs);
326         } else {
327                 const struct exception_table_entry *fixup;
328                 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
329                 if (fixup)
330                         regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
331 		else {
332 			enum bug_trap_type btt;
333 
334 			btt = report_bug(regs->psw.addr & PSW_ADDR_INSN);
335 			if (btt == BUG_TRAP_TYPE_WARN)
336 				return;
337 			die(str, regs, interruption_code);
338 		}
339         }
340 }
341 
342 static inline void __user *get_check_address(struct pt_regs *regs)
343 {
344 	return (void __user *)((regs->psw.addr-S390_lowcore.pgm_ilc) & PSW_ADDR_INSN);
345 }
346 
347 void __kprobes do_single_step(struct pt_regs *regs)
348 {
349 	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0,
350 					SIGTRAP) == NOTIFY_STOP){
351 		return;
352 	}
353 	if ((current->ptrace & PT_PTRACED) != 0)
354 		force_sig(SIGTRAP, current);
355 }
356 
357 static void default_trap_handler(struct pt_regs * regs, long interruption_code)
358 {
359         if (regs->psw.mask & PSW_MASK_PSTATE) {
360 		local_irq_enable();
361 		do_exit(SIGSEGV);
362 		report_user_fault(interruption_code, regs);
363 	} else
364 		die("Unknown program exception", regs, interruption_code);
365 }
366 
367 #define DO_ERROR_INFO(signr, str, name, sicode, siaddr) \
368 static void name(struct pt_regs * regs, long interruption_code) \
369 { \
370         siginfo_t info; \
371         info.si_signo = signr; \
372         info.si_errno = 0; \
373         info.si_code = sicode; \
374 	info.si_addr = siaddr; \
375         do_trap(interruption_code, signr, str, regs, &info); \
376 }
377 
378 DO_ERROR_INFO(SIGILL, "addressing exception", addressing_exception,
379 	      ILL_ILLADR, get_check_address(regs))
380 DO_ERROR_INFO(SIGILL,  "execute exception", execute_exception,
381 	      ILL_ILLOPN, get_check_address(regs))
382 DO_ERROR_INFO(SIGFPE,  "fixpoint divide exception", divide_exception,
383 	      FPE_INTDIV, get_check_address(regs))
384 DO_ERROR_INFO(SIGFPE,  "fixpoint overflow exception", overflow_exception,
385 	      FPE_INTOVF, get_check_address(regs))
386 DO_ERROR_INFO(SIGFPE,  "HFP overflow exception", hfp_overflow_exception,
387 	      FPE_FLTOVF, get_check_address(regs))
388 DO_ERROR_INFO(SIGFPE,  "HFP underflow exception", hfp_underflow_exception,
389 	      FPE_FLTUND, get_check_address(regs))
390 DO_ERROR_INFO(SIGFPE,  "HFP significance exception", hfp_significance_exception,
391 	      FPE_FLTRES, get_check_address(regs))
392 DO_ERROR_INFO(SIGFPE,  "HFP divide exception", hfp_divide_exception,
393 	      FPE_FLTDIV, get_check_address(regs))
394 DO_ERROR_INFO(SIGFPE,  "HFP square root exception", hfp_sqrt_exception,
395 	      FPE_FLTINV, get_check_address(regs))
396 DO_ERROR_INFO(SIGILL,  "operand exception", operand_exception,
397 	      ILL_ILLOPN, get_check_address(regs))
398 DO_ERROR_INFO(SIGILL,  "privileged operation", privileged_op,
399 	      ILL_PRVOPC, get_check_address(regs))
400 DO_ERROR_INFO(SIGILL,  "special operation exception", special_op_exception,
401 	      ILL_ILLOPN, get_check_address(regs))
402 DO_ERROR_INFO(SIGILL,  "translation exception", translation_exception,
403 	      ILL_ILLOPN, get_check_address(regs))
404 
405 static inline void
406 do_fp_trap(struct pt_regs *regs, void __user *location,
407            int fpc, long interruption_code)
408 {
409 	siginfo_t si;
410 
411 	si.si_signo = SIGFPE;
412 	si.si_errno = 0;
413 	si.si_addr = location;
414 	si.si_code = 0;
415 	/* FPC[2] is Data Exception Code */
416 	if ((fpc & 0x00000300) == 0) {
417 		/* bits 6 and 7 of DXC are 0 iff IEEE exception */
418 		if (fpc & 0x8000) /* invalid fp operation */
419 			si.si_code = FPE_FLTINV;
420 		else if (fpc & 0x4000) /* div by 0 */
421 			si.si_code = FPE_FLTDIV;
422 		else if (fpc & 0x2000) /* overflow */
423 			si.si_code = FPE_FLTOVF;
424 		else if (fpc & 0x1000) /* underflow */
425 			si.si_code = FPE_FLTUND;
426 		else if (fpc & 0x0800) /* inexact */
427 			si.si_code = FPE_FLTRES;
428 	}
429 	current->thread.ieee_instruction_pointer = (addr_t) location;
430 	do_trap(interruption_code, SIGFPE,
431 		"floating point exception", regs, &si);
432 }
433 
434 static void illegal_op(struct pt_regs * regs, long interruption_code)
435 {
436 	siginfo_t info;
437         __u8 opcode[6];
438 	__u16 __user *location;
439 	int signal = 0;
440 
441 	location = get_check_address(regs);
442 
443 	/*
444 	 * We got all needed information from the lowcore and can
445 	 * now safely switch on interrupts.
446 	 */
447 	if (regs->psw.mask & PSW_MASK_PSTATE)
448 		local_irq_enable();
449 
450 	if (regs->psw.mask & PSW_MASK_PSTATE) {
451 		if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
452 			return;
453 		if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
454 			if (current->ptrace & PT_PTRACED)
455 				force_sig(SIGTRAP, current);
456 			else
457 				signal = SIGILL;
458 #ifdef CONFIG_MATHEMU
459 		} else if (opcode[0] == 0xb3) {
460 			if (get_user(*((__u16 *) (opcode+2)), location+1))
461 				return;
462 			signal = math_emu_b3(opcode, regs);
463                 } else if (opcode[0] == 0xed) {
464 			if (get_user(*((__u32 *) (opcode+2)),
465 				     (__u32 __user *)(location+1)))
466 				return;
467 			signal = math_emu_ed(opcode, regs);
468 		} else if (*((__u16 *) opcode) == 0xb299) {
469 			if (get_user(*((__u16 *) (opcode+2)), location+1))
470 				return;
471 			signal = math_emu_srnm(opcode, regs);
472 		} else if (*((__u16 *) opcode) == 0xb29c) {
473 			if (get_user(*((__u16 *) (opcode+2)), location+1))
474 				return;
475 			signal = math_emu_stfpc(opcode, regs);
476 		} else if (*((__u16 *) opcode) == 0xb29d) {
477 			if (get_user(*((__u16 *) (opcode+2)), location+1))
478 				return;
479 			signal = math_emu_lfpc(opcode, regs);
480 #endif
481 		} else
482 			signal = SIGILL;
483 	} else {
484 		/*
485 		 * If we get an illegal op in kernel mode, send it through the
486 		 * kprobes notifier. If kprobes doesn't pick it up, SIGILL
487 		 */
488 		if (notify_die(DIE_BPT, "bpt", regs, interruption_code,
489 			       3, SIGTRAP) != NOTIFY_STOP)
490 			signal = SIGILL;
491 	}
492 
493 #ifdef CONFIG_MATHEMU
494         if (signal == SIGFPE)
495 		do_fp_trap(regs, location,
496                            current->thread.fp_regs.fpc, interruption_code);
497         else if (signal == SIGSEGV) {
498 		info.si_signo = signal;
499 		info.si_errno = 0;
500 		info.si_code = SEGV_MAPERR;
501 		info.si_addr = (void __user *) location;
502 		do_trap(interruption_code, signal,
503 			"user address fault", regs, &info);
504 	} else
505 #endif
506         if (signal) {
507 		info.si_signo = signal;
508 		info.si_errno = 0;
509 		info.si_code = ILL_ILLOPC;
510 		info.si_addr = (void __user *) location;
511 		do_trap(interruption_code, signal,
512 			"illegal operation", regs, &info);
513 	}
514 }
515 
516 
517 #ifdef CONFIG_MATHEMU
518 asmlinkage void
519 specification_exception(struct pt_regs * regs, long interruption_code)
520 {
521         __u8 opcode[6];
522 	__u16 __user *location = NULL;
523 	int signal = 0;
524 
525 	location = (__u16 __user *) get_check_address(regs);
526 
527 	/*
528 	 * We got all needed information from the lowcore and can
529 	 * now safely switch on interrupts.
530 	 */
531         if (regs->psw.mask & PSW_MASK_PSTATE)
532 		local_irq_enable();
533 
534         if (regs->psw.mask & PSW_MASK_PSTATE) {
535 		get_user(*((__u16 *) opcode), location);
536 		switch (opcode[0]) {
537 		case 0x28: /* LDR Rx,Ry   */
538 			signal = math_emu_ldr(opcode);
539 			break;
540 		case 0x38: /* LER Rx,Ry   */
541 			signal = math_emu_ler(opcode);
542 			break;
543 		case 0x60: /* STD R,D(X,B) */
544 			get_user(*((__u16 *) (opcode+2)), location+1);
545 			signal = math_emu_std(opcode, regs);
546 			break;
547 		case 0x68: /* LD R,D(X,B) */
548 			get_user(*((__u16 *) (opcode+2)), location+1);
549 			signal = math_emu_ld(opcode, regs);
550 			break;
551 		case 0x70: /* STE R,D(X,B) */
552 			get_user(*((__u16 *) (opcode+2)), location+1);
553 			signal = math_emu_ste(opcode, regs);
554 			break;
555 		case 0x78: /* LE R,D(X,B) */
556 			get_user(*((__u16 *) (opcode+2)), location+1);
557 			signal = math_emu_le(opcode, regs);
558 			break;
559 		default:
560 			signal = SIGILL;
561 			break;
562                 }
563         } else
564 		signal = SIGILL;
565 
566         if (signal == SIGFPE)
567 		do_fp_trap(regs, location,
568                            current->thread.fp_regs.fpc, interruption_code);
569         else if (signal) {
570 		siginfo_t info;
571 		info.si_signo = signal;
572 		info.si_errno = 0;
573 		info.si_code = ILL_ILLOPN;
574 		info.si_addr = location;
575 		do_trap(interruption_code, signal,
576 			"specification exception", regs, &info);
577 	}
578 }
579 #else
580 DO_ERROR_INFO(SIGILL, "specification exception", specification_exception,
581 	      ILL_ILLOPN, get_check_address(regs));
582 #endif
583 
584 static void data_exception(struct pt_regs * regs, long interruption_code)
585 {
586 	__u16 __user *location;
587 	int signal = 0;
588 
589 	location = get_check_address(regs);
590 
591 	/*
592 	 * We got all needed information from the lowcore and can
593 	 * now safely switch on interrupts.
594 	 */
595 	if (regs->psw.mask & PSW_MASK_PSTATE)
596 		local_irq_enable();
597 
598 	if (MACHINE_HAS_IEEE)
599 		asm volatile("stfpc %0" : "=m" (current->thread.fp_regs.fpc));
600 
601 #ifdef CONFIG_MATHEMU
602         else if (regs->psw.mask & PSW_MASK_PSTATE) {
603         	__u8 opcode[6];
604 		get_user(*((__u16 *) opcode), location);
605 		switch (opcode[0]) {
606 		case 0x28: /* LDR Rx,Ry   */
607 			signal = math_emu_ldr(opcode);
608 			break;
609 		case 0x38: /* LER Rx,Ry   */
610 			signal = math_emu_ler(opcode);
611 			break;
612 		case 0x60: /* STD R,D(X,B) */
613 			get_user(*((__u16 *) (opcode+2)), location+1);
614 			signal = math_emu_std(opcode, regs);
615 			break;
616 		case 0x68: /* LD R,D(X,B) */
617 			get_user(*((__u16 *) (opcode+2)), location+1);
618 			signal = math_emu_ld(opcode, regs);
619 			break;
620 		case 0x70: /* STE R,D(X,B) */
621 			get_user(*((__u16 *) (opcode+2)), location+1);
622 			signal = math_emu_ste(opcode, regs);
623 			break;
624 		case 0x78: /* LE R,D(X,B) */
625 			get_user(*((__u16 *) (opcode+2)), location+1);
626 			signal = math_emu_le(opcode, regs);
627 			break;
628 		case 0xb3:
629 			get_user(*((__u16 *) (opcode+2)), location+1);
630 			signal = math_emu_b3(opcode, regs);
631 			break;
632                 case 0xed:
633 			get_user(*((__u32 *) (opcode+2)),
634 				 (__u32 __user *)(location+1));
635 			signal = math_emu_ed(opcode, regs);
636 			break;
637 	        case 0xb2:
638 			if (opcode[1] == 0x99) {
639 				get_user(*((__u16 *) (opcode+2)), location+1);
640 				signal = math_emu_srnm(opcode, regs);
641 			} else if (opcode[1] == 0x9c) {
642 				get_user(*((__u16 *) (opcode+2)), location+1);
643 				signal = math_emu_stfpc(opcode, regs);
644 			} else if (opcode[1] == 0x9d) {
645 				get_user(*((__u16 *) (opcode+2)), location+1);
646 				signal = math_emu_lfpc(opcode, regs);
647 			} else
648 				signal = SIGILL;
649 			break;
650 		default:
651 			signal = SIGILL;
652 			break;
653                 }
654         }
655 #endif
656 	if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
657 		signal = SIGFPE;
658 	else
659 		signal = SIGILL;
660         if (signal == SIGFPE)
661 		do_fp_trap(regs, location,
662                            current->thread.fp_regs.fpc, interruption_code);
663         else if (signal) {
664 		siginfo_t info;
665 		info.si_signo = signal;
666 		info.si_errno = 0;
667 		info.si_code = ILL_ILLOPN;
668 		info.si_addr = location;
669 		do_trap(interruption_code, signal,
670 			"data exception", regs, &info);
671 	}
672 }
673 
674 static void space_switch_exception(struct pt_regs * regs, long int_code)
675 {
676         siginfo_t info;
677 
678 	/* Set user psw back to home space mode. */
679 	if (regs->psw.mask & PSW_MASK_PSTATE)
680 		regs->psw.mask |= PSW_ASC_HOME;
681 	/* Send SIGILL. */
682         info.si_signo = SIGILL;
683         info.si_errno = 0;
684         info.si_code = ILL_PRVOPC;
685         info.si_addr = get_check_address(regs);
686         do_trap(int_code, SIGILL, "space switch event", regs, &info);
687 }
688 
689 asmlinkage void kernel_stack_overflow(struct pt_regs * regs)
690 {
691 	bust_spinlocks(1);
692 	printk("Kernel stack overflow.\n");
693 	show_regs(regs);
694 	bust_spinlocks(0);
695 	panic("Corrupt kernel stack, can't continue.");
696 }
697 
698 /* init is done in lowcore.S and head.S */
699 
700 void __init trap_init(void)
701 {
702         int i;
703 
704         for (i = 0; i < 128; i++)
705           pgm_check_table[i] = &default_trap_handler;
706         pgm_check_table[1] = &illegal_op;
707         pgm_check_table[2] = &privileged_op;
708         pgm_check_table[3] = &execute_exception;
709         pgm_check_table[4] = &do_protection_exception;
710         pgm_check_table[5] = &addressing_exception;
711         pgm_check_table[6] = &specification_exception;
712         pgm_check_table[7] = &data_exception;
713         pgm_check_table[8] = &overflow_exception;
714         pgm_check_table[9] = &divide_exception;
715         pgm_check_table[0x0A] = &overflow_exception;
716         pgm_check_table[0x0B] = &divide_exception;
717         pgm_check_table[0x0C] = &hfp_overflow_exception;
718         pgm_check_table[0x0D] = &hfp_underflow_exception;
719         pgm_check_table[0x0E] = &hfp_significance_exception;
720         pgm_check_table[0x0F] = &hfp_divide_exception;
721         pgm_check_table[0x10] = &do_dat_exception;
722         pgm_check_table[0x11] = &do_dat_exception;
723         pgm_check_table[0x12] = &translation_exception;
724         pgm_check_table[0x13] = &special_op_exception;
725 #ifdef CONFIG_64BIT
726         pgm_check_table[0x38] = &do_dat_exception;
727 	pgm_check_table[0x39] = &do_dat_exception;
728 	pgm_check_table[0x3A] = &do_dat_exception;
729         pgm_check_table[0x3B] = &do_dat_exception;
730 #endif /* CONFIG_64BIT */
731         pgm_check_table[0x15] = &operand_exception;
732         pgm_check_table[0x1C] = &space_switch_exception;
733         pgm_check_table[0x1D] = &hfp_sqrt_exception;
734 	pgm_check_table[0x40] = &do_monitor_call;
735 	pfault_irq_init();
736 }
737