xref: /linux/arch/s390/kernel/traps.c (revision f24e9f586b377749dff37554696cf3a105540c94)
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 
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 #ifdef CONFIG_PFAULT
62 extern int pfault_init(void);
63 extern void pfault_fini(void);
64 extern void pfault_interrupt(struct pt_regs *regs, __u16 error_code);
65 static ext_int_info_t ext_int_pfault;
66 #endif
67 extern pgm_check_handler_t do_monitor_call;
68 
69 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
70 
71 #ifndef CONFIG_64BIT
72 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
73 static int kstack_depth_to_print = 12;
74 #else /* CONFIG_64BIT */
75 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
76 static int kstack_depth_to_print = 20;
77 #endif /* CONFIG_64BIT */
78 
79 ATOMIC_NOTIFIER_HEAD(s390die_chain);
80 
81 int register_die_notifier(struct notifier_block *nb)
82 {
83 	return atomic_notifier_chain_register(&s390die_chain, nb);
84 }
85 EXPORT_SYMBOL(register_die_notifier);
86 
87 int unregister_die_notifier(struct notifier_block *nb)
88 {
89 	return atomic_notifier_chain_unregister(&s390die_chain, nb);
90 }
91 EXPORT_SYMBOL(unregister_die_notifier);
92 
93 /*
94  * For show_trace we have tree different stack to consider:
95  *   - the panic stack which is used if the kernel stack has overflown
96  *   - the asynchronous interrupt stack (cpu related)
97  *   - the synchronous kernel stack (process related)
98  * The stack trace can start at any of the three stack and can potentially
99  * touch all of them. The order is: panic stack, async stack, sync stack.
100  */
101 static unsigned long
102 __show_trace(unsigned long sp, unsigned long low, unsigned long high)
103 {
104 	struct stack_frame *sf;
105 	struct pt_regs *regs;
106 
107 	while (1) {
108 		sp = sp & PSW_ADDR_INSN;
109 		if (sp < low || sp > high - sizeof(*sf))
110 			return sp;
111 		sf = (struct stack_frame *) sp;
112 		printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
113 		print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
114 		/* Follow the backchain. */
115 		while (1) {
116 			low = sp;
117 			sp = sf->back_chain & PSW_ADDR_INSN;
118 			if (!sp)
119 				break;
120 			if (sp <= low || sp > high - sizeof(*sf))
121 				return sp;
122 			sf = (struct stack_frame *) sp;
123 			printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
124 			print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
125 		}
126 		/* Zero backchain detected, check for interrupt frame. */
127 		sp = (unsigned long) (sf + 1);
128 		if (sp <= low || sp > high - sizeof(*regs))
129 			return sp;
130 		regs = (struct pt_regs *) sp;
131 		printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
132 		print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
133 		low = sp;
134 		sp = regs->gprs[15];
135 	}
136 }
137 
138 void show_trace(struct task_struct *task, unsigned long * stack)
139 {
140 	register unsigned long __r15 asm ("15");
141 	unsigned long sp;
142 
143 	sp = (unsigned long) stack;
144 	if (!sp)
145 		sp = task ? task->thread.ksp : __r15;
146 	printk("Call Trace:\n");
147 #ifdef CONFIG_CHECK_STACK
148 	sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
149 			  S390_lowcore.panic_stack);
150 #endif
151 	sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
152 			  S390_lowcore.async_stack);
153 	if (task)
154 		__show_trace(sp, (unsigned long) task_stack_page(task),
155 			     (unsigned long) task_stack_page(task) + THREAD_SIZE);
156 	else
157 		__show_trace(sp, S390_lowcore.thread_info,
158 			     S390_lowcore.thread_info + THREAD_SIZE);
159 	printk("\n");
160 }
161 
162 void show_stack(struct task_struct *task, unsigned long *sp)
163 {
164 	register unsigned long * __r15 asm ("15");
165 	unsigned long *stack;
166 	int i;
167 
168 	if (!sp)
169 		stack = task ? (unsigned long *) task->thread.ksp : __r15;
170 	else
171 		stack = sp;
172 
173 	for (i = 0; i < kstack_depth_to_print; i++) {
174 		if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
175 			break;
176 		if (i && ((i * sizeof (long) % 32) == 0))
177 			printk("\n       ");
178 		printk("%p ", (void *)*stack++);
179 	}
180 	printk("\n");
181 	show_trace(task, sp);
182 }
183 
184 /*
185  * The architecture-independent dump_stack generator
186  */
187 void dump_stack(void)
188 {
189 	show_stack(NULL, NULL);
190 }
191 
192 EXPORT_SYMBOL(dump_stack);
193 
194 void show_registers(struct pt_regs *regs)
195 {
196 	mm_segment_t old_fs;
197 	char *mode;
198 	int i;
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("%s GPRS: " FOURLONG, mode,
206 	       regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
207 	printk("           " FOURLONG,
208 	       regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
209 	printk("           " FOURLONG,
210 	       regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
211 	printk("           " FOURLONG,
212 	       regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
213 
214 #if 0
215 	/* FIXME: this isn't needed any more but it changes the ksymoops
216 	 * input. To remove or not to remove ... */
217 	save_access_regs(regs->acrs);
218 	printk("%s ACRS: %08x %08x %08x %08x\n", mode,
219 	       regs->acrs[0], regs->acrs[1], regs->acrs[2], regs->acrs[3]);
220 	printk("           %08x %08x %08x %08x\n",
221 	       regs->acrs[4], regs->acrs[5], regs->acrs[6], regs->acrs[7]);
222 	printk("           %08x %08x %08x %08x\n",
223 	       regs->acrs[8], regs->acrs[9], regs->acrs[10], regs->acrs[11]);
224 	printk("           %08x %08x %08x %08x\n",
225 	       regs->acrs[12], regs->acrs[13], regs->acrs[14], regs->acrs[15]);
226 #endif
227 
228 	/*
229 	 * Print the first 20 byte of the instruction stream at the
230 	 * time of the fault.
231 	 */
232 	old_fs = get_fs();
233 	if (regs->psw.mask & PSW_MASK_PSTATE)
234 		set_fs(USER_DS);
235 	else
236 		set_fs(KERNEL_DS);
237 	printk("%s Code: ", mode);
238 	for (i = 0; i < 20; i++) {
239 		unsigned char c;
240 		if (__get_user(c, (char __user *)(regs->psw.addr + i))) {
241 			printk(" Bad PSW.");
242 			break;
243 		}
244 		printk("%02x ", c);
245 	}
246 	set_fs(old_fs);
247 
248 	printk("\n");
249 }
250 
251 /* This is called from fs/proc/array.c */
252 char *task_show_regs(struct task_struct *task, char *buffer)
253 {
254 	struct pt_regs *regs;
255 
256 	regs = task_pt_regs(task);
257 	buffer += sprintf(buffer, "task: %p, ksp: %p\n",
258 		       task, (void *)task->thread.ksp);
259 	buffer += sprintf(buffer, "User PSW : %p %p\n",
260 		       (void *) regs->psw.mask, (void *)regs->psw.addr);
261 
262 	buffer += sprintf(buffer, "User GPRS: " FOURLONG,
263 			  regs->gprs[0], regs->gprs[1],
264 			  regs->gprs[2], regs->gprs[3]);
265 	buffer += sprintf(buffer, "           " FOURLONG,
266 			  regs->gprs[4], regs->gprs[5],
267 			  regs->gprs[6], regs->gprs[7]);
268 	buffer += sprintf(buffer, "           " FOURLONG,
269 			  regs->gprs[8], regs->gprs[9],
270 			  regs->gprs[10], regs->gprs[11]);
271 	buffer += sprintf(buffer, "           " FOURLONG,
272 			  regs->gprs[12], regs->gprs[13],
273 			  regs->gprs[14], regs->gprs[15]);
274 	buffer += sprintf(buffer, "User ACRS: %08x %08x %08x %08x\n",
275 			  task->thread.acrs[0], task->thread.acrs[1],
276 			  task->thread.acrs[2], task->thread.acrs[3]);
277 	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
278 			  task->thread.acrs[4], task->thread.acrs[5],
279 			  task->thread.acrs[6], task->thread.acrs[7]);
280 	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
281 			  task->thread.acrs[8], task->thread.acrs[9],
282 			  task->thread.acrs[10], task->thread.acrs[11]);
283 	buffer += sprintf(buffer, "           %08x %08x %08x %08x\n",
284 			  task->thread.acrs[12], task->thread.acrs[13],
285 			  task->thread.acrs[14], task->thread.acrs[15]);
286 	return buffer;
287 }
288 
289 DEFINE_SPINLOCK(die_lock);
290 
291 void die(const char * str, struct pt_regs * regs, long err)
292 {
293 	static int die_counter;
294 
295 	debug_stop_all();
296 	console_verbose();
297 	spin_lock_irq(&die_lock);
298 	bust_spinlocks(1);
299 	printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
300         show_regs(regs);
301 	bust_spinlocks(0);
302         spin_unlock_irq(&die_lock);
303 	if (in_interrupt())
304 		panic("Fatal exception in interrupt");
305 	if (panic_on_oops)
306 		panic("Fatal exception: panic_on_oops");
307         do_exit(SIGSEGV);
308 }
309 
310 static void inline
311 report_user_fault(long interruption_code, struct pt_regs *regs)
312 {
313 #if defined(CONFIG_SYSCTL)
314 	if (!sysctl_userprocess_debug)
315 		return;
316 #endif
317 #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
318 	printk("User process fault: interruption code 0x%lX\n",
319 	       interruption_code);
320 	show_regs(regs);
321 #endif
322 }
323 
324 static void __kprobes inline do_trap(long interruption_code, int signr,
325 					char *str, struct pt_regs *regs,
326 					siginfo_t *info)
327 {
328 	/*
329 	 * We got all needed information from the lowcore and can
330 	 * now safely switch on interrupts.
331 	 */
332         if (regs->psw.mask & PSW_MASK_PSTATE)
333 		local_irq_enable();
334 
335 	if (notify_die(DIE_TRAP, str, regs, interruption_code,
336 				interruption_code, signr) == NOTIFY_STOP)
337 		return;
338 
339         if (regs->psw.mask & PSW_MASK_PSTATE) {
340                 struct task_struct *tsk = current;
341 
342                 tsk->thread.trap_no = interruption_code & 0xffff;
343 		force_sig_info(signr, info, tsk);
344 		report_user_fault(interruption_code, regs);
345         } else {
346                 const struct exception_table_entry *fixup;
347                 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
348                 if (fixup)
349                         regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
350                 else
351                         die(str, regs, interruption_code);
352         }
353 }
354 
355 static inline void __user *get_check_address(struct pt_regs *regs)
356 {
357 	return (void __user *)((regs->psw.addr-S390_lowcore.pgm_ilc) & PSW_ADDR_INSN);
358 }
359 
360 void __kprobes do_single_step(struct pt_regs *regs)
361 {
362 	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0,
363 					SIGTRAP) == NOTIFY_STOP){
364 		return;
365 	}
366 	if ((current->ptrace & PT_PTRACED) != 0)
367 		force_sig(SIGTRAP, current);
368 }
369 
370 asmlinkage void
371 default_trap_handler(struct pt_regs * regs, long interruption_code)
372 {
373         if (regs->psw.mask & PSW_MASK_PSTATE) {
374 		local_irq_enable();
375 		do_exit(SIGSEGV);
376 		report_user_fault(interruption_code, regs);
377 	} else
378 		die("Unknown program exception", regs, interruption_code);
379 }
380 
381 #define DO_ERROR_INFO(signr, str, name, sicode, siaddr) \
382 asmlinkage void name(struct pt_regs * regs, long interruption_code) \
383 { \
384         siginfo_t info; \
385         info.si_signo = signr; \
386         info.si_errno = 0; \
387         info.si_code = sicode; \
388 	info.si_addr = siaddr; \
389         do_trap(interruption_code, signr, str, regs, &info); \
390 }
391 
392 DO_ERROR_INFO(SIGILL, "addressing exception", addressing_exception,
393 	      ILL_ILLADR, get_check_address(regs))
394 DO_ERROR_INFO(SIGILL,  "execute exception", execute_exception,
395 	      ILL_ILLOPN, get_check_address(regs))
396 DO_ERROR_INFO(SIGFPE,  "fixpoint divide exception", divide_exception,
397 	      FPE_INTDIV, get_check_address(regs))
398 DO_ERROR_INFO(SIGFPE,  "fixpoint overflow exception", overflow_exception,
399 	      FPE_INTOVF, get_check_address(regs))
400 DO_ERROR_INFO(SIGFPE,  "HFP overflow exception", hfp_overflow_exception,
401 	      FPE_FLTOVF, get_check_address(regs))
402 DO_ERROR_INFO(SIGFPE,  "HFP underflow exception", hfp_underflow_exception,
403 	      FPE_FLTUND, get_check_address(regs))
404 DO_ERROR_INFO(SIGFPE,  "HFP significance exception", hfp_significance_exception,
405 	      FPE_FLTRES, get_check_address(regs))
406 DO_ERROR_INFO(SIGFPE,  "HFP divide exception", hfp_divide_exception,
407 	      FPE_FLTDIV, get_check_address(regs))
408 DO_ERROR_INFO(SIGFPE,  "HFP square root exception", hfp_sqrt_exception,
409 	      FPE_FLTINV, get_check_address(regs))
410 DO_ERROR_INFO(SIGILL,  "operand exception", operand_exception,
411 	      ILL_ILLOPN, get_check_address(regs))
412 DO_ERROR_INFO(SIGILL,  "privileged operation", privileged_op,
413 	      ILL_PRVOPC, get_check_address(regs))
414 DO_ERROR_INFO(SIGILL,  "special operation exception", special_op_exception,
415 	      ILL_ILLOPN, get_check_address(regs))
416 DO_ERROR_INFO(SIGILL,  "translation exception", translation_exception,
417 	      ILL_ILLOPN, get_check_address(regs))
418 
419 static inline void
420 do_fp_trap(struct pt_regs *regs, void __user *location,
421            int fpc, long interruption_code)
422 {
423 	siginfo_t si;
424 
425 	si.si_signo = SIGFPE;
426 	si.si_errno = 0;
427 	si.si_addr = location;
428 	si.si_code = 0;
429 	/* FPC[2] is Data Exception Code */
430 	if ((fpc & 0x00000300) == 0) {
431 		/* bits 6 and 7 of DXC are 0 iff IEEE exception */
432 		if (fpc & 0x8000) /* invalid fp operation */
433 			si.si_code = FPE_FLTINV;
434 		else if (fpc & 0x4000) /* div by 0 */
435 			si.si_code = FPE_FLTDIV;
436 		else if (fpc & 0x2000) /* overflow */
437 			si.si_code = FPE_FLTOVF;
438 		else if (fpc & 0x1000) /* underflow */
439 			si.si_code = FPE_FLTUND;
440 		else if (fpc & 0x0800) /* inexact */
441 			si.si_code = FPE_FLTRES;
442 	}
443 	current->thread.ieee_instruction_pointer = (addr_t) location;
444 	do_trap(interruption_code, SIGFPE,
445 		"floating point exception", regs, &si);
446 }
447 
448 asmlinkage void illegal_op(struct pt_regs * regs, long interruption_code)
449 {
450 	siginfo_t info;
451         __u8 opcode[6];
452 	__u16 __user *location;
453 	int signal = 0;
454 
455 	location = get_check_address(regs);
456 
457 	/*
458 	 * We got all needed information from the lowcore and can
459 	 * now safely switch on interrupts.
460 	 */
461 	if (regs->psw.mask & PSW_MASK_PSTATE)
462 		local_irq_enable();
463 
464 	if (regs->psw.mask & PSW_MASK_PSTATE) {
465 		get_user(*((__u16 *) opcode), (__u16 __user *) location);
466 		if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
467 			if (current->ptrace & PT_PTRACED)
468 				force_sig(SIGTRAP, current);
469 			else
470 				signal = SIGILL;
471 #ifdef CONFIG_MATHEMU
472 		} else if (opcode[0] == 0xb3) {
473 			get_user(*((__u16 *) (opcode+2)), location+1);
474 			signal = math_emu_b3(opcode, regs);
475                 } else if (opcode[0] == 0xed) {
476 			get_user(*((__u32 *) (opcode+2)),
477 				 (__u32 *)(location+1));
478 			signal = math_emu_ed(opcode, regs);
479 		} else if (*((__u16 *) opcode) == 0xb299) {
480 			get_user(*((__u16 *) (opcode+2)), location+1);
481 			signal = math_emu_srnm(opcode, regs);
482 		} else if (*((__u16 *) opcode) == 0xb29c) {
483 			get_user(*((__u16 *) (opcode+2)), location+1);
484 			signal = math_emu_stfpc(opcode, regs);
485 		} else if (*((__u16 *) opcode) == 0xb29d) {
486 			get_user(*((__u16 *) (opcode+2)), location+1);
487 			signal = math_emu_lfpc(opcode, regs);
488 #endif
489 		} else
490 			signal = SIGILL;
491 	} else
492 		signal = SIGILL;
493 
494 #ifdef CONFIG_MATHEMU
495         if (signal == SIGFPE)
496 		do_fp_trap(regs, location,
497                            current->thread.fp_regs.fpc, interruption_code);
498         else if (signal == SIGSEGV) {
499 		info.si_signo = signal;
500 		info.si_errno = 0;
501 		info.si_code = SEGV_MAPERR;
502 		info.si_addr = (void *) location;
503 		do_trap(interruption_code, signal,
504 			"user address fault", regs, &info);
505 	} else
506 #endif
507         if (signal) {
508 		info.si_signo = signal;
509 		info.si_errno = 0;
510 		info.si_code = ILL_ILLOPC;
511 		info.si_addr = (void __user *) location;
512 		do_trap(interruption_code, signal,
513 			"illegal operation", regs, &info);
514 	}
515 }
516 
517 
518 #ifdef CONFIG_MATHEMU
519 asmlinkage void
520 specification_exception(struct pt_regs * regs, long interruption_code)
521 {
522         __u8 opcode[6];
523 	__u16 *location = NULL;
524 	int signal = 0;
525 
526 	location = (__u16 *) get_check_address(regs);
527 
528 	/*
529 	 * We got all needed information from the lowcore and can
530 	 * now safely switch on interrupts.
531 	 */
532         if (regs->psw.mask & PSW_MASK_PSTATE)
533 		local_irq_enable();
534 
535         if (regs->psw.mask & PSW_MASK_PSTATE) {
536 		get_user(*((__u16 *) opcode), location);
537 		switch (opcode[0]) {
538 		case 0x28: /* LDR Rx,Ry   */
539 			signal = math_emu_ldr(opcode);
540 			break;
541 		case 0x38: /* LER Rx,Ry   */
542 			signal = math_emu_ler(opcode);
543 			break;
544 		case 0x60: /* STD R,D(X,B) */
545 			get_user(*((__u16 *) (opcode+2)), location+1);
546 			signal = math_emu_std(opcode, regs);
547 			break;
548 		case 0x68: /* LD R,D(X,B) */
549 			get_user(*((__u16 *) (opcode+2)), location+1);
550 			signal = math_emu_ld(opcode, regs);
551 			break;
552 		case 0x70: /* STE R,D(X,B) */
553 			get_user(*((__u16 *) (opcode+2)), location+1);
554 			signal = math_emu_ste(opcode, regs);
555 			break;
556 		case 0x78: /* LE R,D(X,B) */
557 			get_user(*((__u16 *) (opcode+2)), location+1);
558 			signal = math_emu_le(opcode, regs);
559 			break;
560 		default:
561 			signal = SIGILL;
562 			break;
563                 }
564         } else
565 		signal = SIGILL;
566 
567         if (signal == SIGFPE)
568 		do_fp_trap(regs, location,
569                            current->thread.fp_regs.fpc, interruption_code);
570         else if (signal) {
571 		siginfo_t info;
572 		info.si_signo = signal;
573 		info.si_errno = 0;
574 		info.si_code = ILL_ILLOPN;
575 		info.si_addr = location;
576 		do_trap(interruption_code, signal,
577 			"specification exception", regs, &info);
578 	}
579 }
580 #else
581 DO_ERROR_INFO(SIGILL, "specification exception", specification_exception,
582 	      ILL_ILLOPN, get_check_address(regs));
583 #endif
584 
585 asmlinkage void data_exception(struct pt_regs * regs, long interruption_code)
586 {
587 	__u16 __user *location;
588 	int signal = 0;
589 
590 	location = get_check_address(regs);
591 
592 	/*
593 	 * We got all needed information from the lowcore and can
594 	 * now safely switch on interrupts.
595 	 */
596 	if (regs->psw.mask & PSW_MASK_PSTATE)
597 		local_irq_enable();
598 
599 	if (MACHINE_HAS_IEEE)
600 		__asm__ volatile ("stfpc %0\n\t"
601 				  : "=m" (current->thread.fp_regs.fpc));
602 
603 #ifdef CONFIG_MATHEMU
604         else if (regs->psw.mask & PSW_MASK_PSTATE) {
605         	__u8 opcode[6];
606 		get_user(*((__u16 *) opcode), location);
607 		switch (opcode[0]) {
608 		case 0x28: /* LDR Rx,Ry   */
609 			signal = math_emu_ldr(opcode);
610 			break;
611 		case 0x38: /* LER Rx,Ry   */
612 			signal = math_emu_ler(opcode);
613 			break;
614 		case 0x60: /* STD R,D(X,B) */
615 			get_user(*((__u16 *) (opcode+2)), location+1);
616 			signal = math_emu_std(opcode, regs);
617 			break;
618 		case 0x68: /* LD R,D(X,B) */
619 			get_user(*((__u16 *) (opcode+2)), location+1);
620 			signal = math_emu_ld(opcode, regs);
621 			break;
622 		case 0x70: /* STE R,D(X,B) */
623 			get_user(*((__u16 *) (opcode+2)), location+1);
624 			signal = math_emu_ste(opcode, regs);
625 			break;
626 		case 0x78: /* LE R,D(X,B) */
627 			get_user(*((__u16 *) (opcode+2)), location+1);
628 			signal = math_emu_le(opcode, regs);
629 			break;
630 		case 0xb3:
631 			get_user(*((__u16 *) (opcode+2)), location+1);
632 			signal = math_emu_b3(opcode, regs);
633 			break;
634                 case 0xed:
635 			get_user(*((__u32 *) (opcode+2)),
636 				 (__u32 *)(location+1));
637 			signal = math_emu_ed(opcode, regs);
638 			break;
639 	        case 0xb2:
640 			if (opcode[1] == 0x99) {
641 				get_user(*((__u16 *) (opcode+2)), location+1);
642 				signal = math_emu_srnm(opcode, regs);
643 			} else if (opcode[1] == 0x9c) {
644 				get_user(*((__u16 *) (opcode+2)), location+1);
645 				signal = math_emu_stfpc(opcode, regs);
646 			} else if (opcode[1] == 0x9d) {
647 				get_user(*((__u16 *) (opcode+2)), location+1);
648 				signal = math_emu_lfpc(opcode, regs);
649 			} else
650 				signal = SIGILL;
651 			break;
652 		default:
653 			signal = SIGILL;
654 			break;
655                 }
656         }
657 #endif
658 	if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
659 		signal = SIGFPE;
660 	else
661 		signal = SIGILL;
662         if (signal == SIGFPE)
663 		do_fp_trap(regs, location,
664                            current->thread.fp_regs.fpc, interruption_code);
665         else if (signal) {
666 		siginfo_t info;
667 		info.si_signo = signal;
668 		info.si_errno = 0;
669 		info.si_code = ILL_ILLOPN;
670 		info.si_addr = location;
671 		do_trap(interruption_code, signal,
672 			"data exception", regs, &info);
673 	}
674 }
675 
676 asmlinkage void space_switch_exception(struct pt_regs * regs, long int_code)
677 {
678         siginfo_t info;
679 
680 	/* Set user psw back to home space mode. */
681 	if (regs->psw.mask & PSW_MASK_PSTATE)
682 		regs->psw.mask |= PSW_ASC_HOME;
683 	/* Send SIGILL. */
684         info.si_signo = SIGILL;
685         info.si_errno = 0;
686         info.si_code = ILL_PRVOPC;
687         info.si_addr = get_check_address(regs);
688         do_trap(int_code, SIGILL, "space switch event", regs, &info);
689 }
690 
691 asmlinkage void kernel_stack_overflow(struct pt_regs * regs)
692 {
693 	bust_spinlocks(1);
694 	printk("Kernel stack overflow.\n");
695 	show_regs(regs);
696 	bust_spinlocks(0);
697 	panic("Corrupt kernel stack, can't continue.");
698 }
699 
700 /* init is done in lowcore.S and head.S */
701 
702 void __init trap_init(void)
703 {
704         int i;
705 
706         for (i = 0; i < 128; i++)
707           pgm_check_table[i] = &default_trap_handler;
708         pgm_check_table[1] = &illegal_op;
709         pgm_check_table[2] = &privileged_op;
710         pgm_check_table[3] = &execute_exception;
711         pgm_check_table[4] = &do_protection_exception;
712         pgm_check_table[5] = &addressing_exception;
713         pgm_check_table[6] = &specification_exception;
714         pgm_check_table[7] = &data_exception;
715         pgm_check_table[8] = &overflow_exception;
716         pgm_check_table[9] = &divide_exception;
717         pgm_check_table[0x0A] = &overflow_exception;
718         pgm_check_table[0x0B] = &divide_exception;
719         pgm_check_table[0x0C] = &hfp_overflow_exception;
720         pgm_check_table[0x0D] = &hfp_underflow_exception;
721         pgm_check_table[0x0E] = &hfp_significance_exception;
722         pgm_check_table[0x0F] = &hfp_divide_exception;
723         pgm_check_table[0x10] = &do_dat_exception;
724         pgm_check_table[0x11] = &do_dat_exception;
725         pgm_check_table[0x12] = &translation_exception;
726         pgm_check_table[0x13] = &special_op_exception;
727 #ifdef CONFIG_64BIT
728         pgm_check_table[0x38] = &do_dat_exception;
729 	pgm_check_table[0x39] = &do_dat_exception;
730 	pgm_check_table[0x3A] = &do_dat_exception;
731         pgm_check_table[0x3B] = &do_dat_exception;
732 #endif /* CONFIG_64BIT */
733         pgm_check_table[0x15] = &operand_exception;
734         pgm_check_table[0x1C] = &space_switch_exception;
735         pgm_check_table[0x1D] = &hfp_sqrt_exception;
736 	pgm_check_table[0x40] = &do_monitor_call;
737 
738 	if (MACHINE_IS_VM) {
739 #ifdef CONFIG_PFAULT
740 		/*
741 		 * Try to get pfault pseudo page faults going.
742 		 */
743 		if (register_early_external_interrupt(0x2603, pfault_interrupt,
744 						      &ext_int_pfault) != 0)
745 			panic("Couldn't request external interrupt 0x2603");
746 
747 		if (pfault_init() == 0)
748 			return;
749 
750 		/* Tough luck, no pfault. */
751 		unregister_early_external_interrupt(0x2603, pfault_interrupt,
752 						    &ext_int_pfault);
753 #endif
754 	}
755 }
756