xref: /openbmc/linux/arch/parisc/kernel/traps.c (revision 4f6cce39)
1 /*
2  *  linux/arch/parisc/traps.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  *  Copyright (C) 1999, 2000  Philipp Rumpf <prumpf@tux.org>
6  */
7 
8 /*
9  * 'Traps.c' handles hardware traps and faults after we have saved some
10  * state in 'asm.s'.
11  */
12 
13 #include <linux/sched.h>
14 #include <linux/sched/debug.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
18 #include <linux/ptrace.h>
19 #include <linux/timer.h>
20 #include <linux/delay.h>
21 #include <linux/mm.h>
22 #include <linux/module.h>
23 #include <linux/smp.h>
24 #include <linux/spinlock.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/console.h>
28 #include <linux/bug.h>
29 #include <linux/ratelimit.h>
30 #include <linux/uaccess.h>
31 
32 #include <asm/assembly.h>
33 #include <asm/io.h>
34 #include <asm/irq.h>
35 #include <asm/traps.h>
36 #include <asm/unaligned.h>
37 #include <linux/atomic.h>
38 #include <asm/smp.h>
39 #include <asm/pdc.h>
40 #include <asm/pdc_chassis.h>
41 #include <asm/unwind.h>
42 #include <asm/tlbflush.h>
43 #include <asm/cacheflush.h>
44 
45 #include "../math-emu/math-emu.h"	/* for handle_fpe() */
46 
47 static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
48 	struct pt_regs *regs);
49 
50 static int printbinary(char *buf, unsigned long x, int nbits)
51 {
52 	unsigned long mask = 1UL << (nbits - 1);
53 	while (mask != 0) {
54 		*buf++ = (mask & x ? '1' : '0');
55 		mask >>= 1;
56 	}
57 	*buf = '\0';
58 
59 	return nbits;
60 }
61 
62 #ifdef CONFIG_64BIT
63 #define RFMT "%016lx"
64 #else
65 #define RFMT "%08lx"
66 #endif
67 #define FFMT "%016llx"	/* fpregs are 64-bit always */
68 
69 #define PRINTREGS(lvl,r,f,fmt,x)	\
70 	printk("%s%s%02d-%02d  " fmt " " fmt " " fmt " " fmt "\n",	\
71 		lvl, f, (x), (x+3), (r)[(x)+0], (r)[(x)+1],		\
72 		(r)[(x)+2], (r)[(x)+3])
73 
74 static void print_gr(char *level, struct pt_regs *regs)
75 {
76 	int i;
77 	char buf[64];
78 
79 	printk("%s\n", level);
80 	printk("%s     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI\n", level);
81 	printbinary(buf, regs->gr[0], 32);
82 	printk("%sPSW: %s %s\n", level, buf, print_tainted());
83 
84 	for (i = 0; i < 32; i += 4)
85 		PRINTREGS(level, regs->gr, "r", RFMT, i);
86 }
87 
88 static void print_fr(char *level, struct pt_regs *regs)
89 {
90 	int i;
91 	char buf[64];
92 	struct { u32 sw[2]; } s;
93 
94 	/* FR are 64bit everywhere. Need to use asm to get the content
95 	 * of fpsr/fper1, and we assume that we won't have a FP Identify
96 	 * in our way, otherwise we're screwed.
97 	 * The fldd is used to restore the T-bit if there was one, as the
98 	 * store clears it anyway.
99 	 * PA2.0 book says "thou shall not use fstw on FPSR/FPERs" - T-Bone */
100 	asm volatile ("fstd %%fr0,0(%1)	\n\t"
101 		      "fldd 0(%1),%%fr0	\n\t"
102 		      : "=m" (s) : "r" (&s) : "r0");
103 
104 	printk("%s\n", level);
105 	printk("%s      VZOUICununcqcqcqcqcqcrmunTDVZOUI\n", level);
106 	printbinary(buf, s.sw[0], 32);
107 	printk("%sFPSR: %s\n", level, buf);
108 	printk("%sFPER1: %08x\n", level, s.sw[1]);
109 
110 	/* here we'll print fr0 again, tho it'll be meaningless */
111 	for (i = 0; i < 32; i += 4)
112 		PRINTREGS(level, regs->fr, "fr", FFMT, i);
113 }
114 
115 void show_regs(struct pt_regs *regs)
116 {
117 	int i, user;
118 	char *level;
119 	unsigned long cr30, cr31;
120 
121 	user = user_mode(regs);
122 	level = user ? KERN_DEBUG : KERN_CRIT;
123 
124 	show_regs_print_info(level);
125 
126 	print_gr(level, regs);
127 
128 	for (i = 0; i < 8; i += 4)
129 		PRINTREGS(level, regs->sr, "sr", RFMT, i);
130 
131 	if (user)
132 		print_fr(level, regs);
133 
134 	cr30 = mfctl(30);
135 	cr31 = mfctl(31);
136 	printk("%s\n", level);
137 	printk("%sIASQ: " RFMT " " RFMT " IAOQ: " RFMT " " RFMT "\n",
138 	       level, regs->iasq[0], regs->iasq[1], regs->iaoq[0], regs->iaoq[1]);
139 	printk("%s IIR: %08lx    ISR: " RFMT "  IOR: " RFMT "\n",
140 	       level, regs->iir, regs->isr, regs->ior);
141 	printk("%s CPU: %8d   CR30: " RFMT " CR31: " RFMT "\n",
142 	       level, current_thread_info()->cpu, cr30, cr31);
143 	printk("%s ORIG_R28: " RFMT "\n", level, regs->orig_r28);
144 
145 	if (user) {
146 		printk("%s IAOQ[0]: " RFMT "\n", level, regs->iaoq[0]);
147 		printk("%s IAOQ[1]: " RFMT "\n", level, regs->iaoq[1]);
148 		printk("%s RP(r2): " RFMT "\n", level, regs->gr[2]);
149 	} else {
150 		printk("%s IAOQ[0]: %pS\n", level, (void *) regs->iaoq[0]);
151 		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
152 		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
153 
154 		parisc_show_stack(current, NULL, regs);
155 	}
156 }
157 
158 static DEFINE_RATELIMIT_STATE(_hppa_rs,
159 	DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST);
160 
161 #define parisc_printk_ratelimited(critical, regs, fmt, ...)	{	      \
162 	if ((critical || show_unhandled_signals) && __ratelimit(&_hppa_rs)) { \
163 		printk(fmt, ##__VA_ARGS__);				      \
164 		show_regs(regs);					      \
165 	}								      \
166 }
167 
168 
169 static void do_show_stack(struct unwind_frame_info *info)
170 {
171 	int i = 1;
172 
173 	printk(KERN_CRIT "Backtrace:\n");
174 	while (i <= 16) {
175 		if (unwind_once(info) < 0 || info->ip == 0)
176 			break;
177 
178 		if (__kernel_text_address(info->ip)) {
179 			printk(KERN_CRIT " [<" RFMT ">] %pS\n",
180 				info->ip, (void *) info->ip);
181 			i++;
182 		}
183 	}
184 	printk(KERN_CRIT "\n");
185 }
186 
187 static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
188 	struct pt_regs *regs)
189 {
190 	struct unwind_frame_info info;
191 	struct task_struct *t;
192 
193 	t = task ? task : current;
194 	if (regs) {
195 		unwind_frame_init(&info, t, regs);
196 		goto show_stack;
197 	}
198 
199 	if (t == current) {
200 		unsigned long sp;
201 
202 HERE:
203 		asm volatile ("copy %%r30, %0" : "=r"(sp));
204 		{
205 			struct pt_regs r;
206 
207 			memset(&r, 0, sizeof(struct pt_regs));
208 			r.iaoq[0] = (unsigned long)&&HERE;
209 			r.gr[2] = (unsigned long)__builtin_return_address(0);
210 			r.gr[30] = sp;
211 
212 			unwind_frame_init(&info, current, &r);
213 		}
214 	} else {
215 		unwind_frame_init_from_blocked_task(&info, t);
216 	}
217 
218 show_stack:
219 	do_show_stack(&info);
220 }
221 
222 void show_stack(struct task_struct *t, unsigned long *sp)
223 {
224 	return parisc_show_stack(t, sp, NULL);
225 }
226 
227 int is_valid_bugaddr(unsigned long iaoq)
228 {
229 	return 1;
230 }
231 
232 void die_if_kernel(char *str, struct pt_regs *regs, long err)
233 {
234 	if (user_mode(regs)) {
235 		if (err == 0)
236 			return; /* STFU */
237 
238 		parisc_printk_ratelimited(1, regs,
239 			KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
240 			current->comm, task_pid_nr(current), str, err, regs->iaoq[0]);
241 
242 		return;
243 	}
244 
245 	oops_in_progress = 1;
246 
247 	oops_enter();
248 
249 	/* Amuse the user in a SPARC fashion */
250 	if (err) printk(KERN_CRIT
251 			"      _______________________________ \n"
252 			"     < Your System ate a SPARC! Gah! >\n"
253 			"      ------------------------------- \n"
254 			"             \\   ^__^\n"
255 			"                 (__)\\       )\\/\\\n"
256 			"                  U  ||----w |\n"
257 			"                     ||     ||\n");
258 
259 	/* unlock the pdc lock if necessary */
260 	pdc_emergency_unlock();
261 
262 	/* maybe the kernel hasn't booted very far yet and hasn't been able
263 	 * to initialize the serial or STI console. In that case we should
264 	 * re-enable the pdc console, so that the user will be able to
265 	 * identify the problem. */
266 	if (!console_drivers)
267 		pdc_console_restart();
268 
269 	if (err)
270 		printk(KERN_CRIT "%s (pid %d): %s (code %ld)\n",
271 			current->comm, task_pid_nr(current), str, err);
272 
273 	/* Wot's wrong wif bein' racy? */
274 	if (current->thread.flags & PARISC_KERNEL_DEATH) {
275 		printk(KERN_CRIT "%s() recursion detected.\n", __func__);
276 		local_irq_enable();
277 		while (1);
278 	}
279 	current->thread.flags |= PARISC_KERNEL_DEATH;
280 
281 	show_regs(regs);
282 	dump_stack();
283 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
284 
285 	if (in_interrupt())
286 		panic("Fatal exception in interrupt");
287 
288 	if (panic_on_oops)
289 		panic("Fatal exception");
290 
291 	oops_exit();
292 	do_exit(SIGSEGV);
293 }
294 
295 /* gdb uses break 4,8 */
296 #define GDB_BREAK_INSN 0x10004
297 static void handle_gdb_break(struct pt_regs *regs, int wot)
298 {
299 	struct siginfo si;
300 
301 	si.si_signo = SIGTRAP;
302 	si.si_errno = 0;
303 	si.si_code = wot;
304 	si.si_addr = (void __user *) (regs->iaoq[0] & ~3);
305 	force_sig_info(SIGTRAP, &si, current);
306 }
307 
308 static void handle_break(struct pt_regs *regs)
309 {
310 	unsigned iir = regs->iir;
311 
312 	if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
313 		/* check if a BUG() or WARN() trapped here.  */
314 		enum bug_trap_type tt;
315 		tt = report_bug(regs->iaoq[0] & ~3, regs);
316 		if (tt == BUG_TRAP_TYPE_WARN) {
317 			regs->iaoq[0] += 4;
318 			regs->iaoq[1] += 4;
319 			return; /* return to next instruction when WARN_ON().  */
320 		}
321 		die_if_kernel("Unknown kernel breakpoint", regs,
322 			(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
323 	}
324 
325 	if (unlikely(iir != GDB_BREAK_INSN))
326 		parisc_printk_ratelimited(0, regs,
327 			KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
328 			iir & 31, (iir>>13) & ((1<<13)-1),
329 			task_pid_nr(current), current->comm);
330 
331 	/* send standard GDB signal */
332 	handle_gdb_break(regs, TRAP_BRKPT);
333 }
334 
335 static void default_trap(int code, struct pt_regs *regs)
336 {
337 	printk(KERN_ERR "Trap %d on CPU %d\n", code, smp_processor_id());
338 	show_regs(regs);
339 }
340 
341 void (*cpu_lpmc) (int code, struct pt_regs *regs) __read_mostly = default_trap;
342 
343 
344 void transfer_pim_to_trap_frame(struct pt_regs *regs)
345 {
346     register int i;
347     extern unsigned int hpmc_pim_data[];
348     struct pdc_hpmc_pim_11 *pim_narrow;
349     struct pdc_hpmc_pim_20 *pim_wide;
350 
351     if (boot_cpu_data.cpu_type >= pcxu) {
352 
353 	pim_wide = (struct pdc_hpmc_pim_20 *)hpmc_pim_data;
354 
355 	/*
356 	 * Note: The following code will probably generate a
357 	 * bunch of truncation error warnings from the compiler.
358 	 * Could be handled with an ifdef, but perhaps there
359 	 * is a better way.
360 	 */
361 
362 	regs->gr[0] = pim_wide->cr[22];
363 
364 	for (i = 1; i < 32; i++)
365 	    regs->gr[i] = pim_wide->gr[i];
366 
367 	for (i = 0; i < 32; i++)
368 	    regs->fr[i] = pim_wide->fr[i];
369 
370 	for (i = 0; i < 8; i++)
371 	    regs->sr[i] = pim_wide->sr[i];
372 
373 	regs->iasq[0] = pim_wide->cr[17];
374 	regs->iasq[1] = pim_wide->iasq_back;
375 	regs->iaoq[0] = pim_wide->cr[18];
376 	regs->iaoq[1] = pim_wide->iaoq_back;
377 
378 	regs->sar  = pim_wide->cr[11];
379 	regs->iir  = pim_wide->cr[19];
380 	regs->isr  = pim_wide->cr[20];
381 	regs->ior  = pim_wide->cr[21];
382     }
383     else {
384 	pim_narrow = (struct pdc_hpmc_pim_11 *)hpmc_pim_data;
385 
386 	regs->gr[0] = pim_narrow->cr[22];
387 
388 	for (i = 1; i < 32; i++)
389 	    regs->gr[i] = pim_narrow->gr[i];
390 
391 	for (i = 0; i < 32; i++)
392 	    regs->fr[i] = pim_narrow->fr[i];
393 
394 	for (i = 0; i < 8; i++)
395 	    regs->sr[i] = pim_narrow->sr[i];
396 
397 	regs->iasq[0] = pim_narrow->cr[17];
398 	regs->iasq[1] = pim_narrow->iasq_back;
399 	regs->iaoq[0] = pim_narrow->cr[18];
400 	regs->iaoq[1] = pim_narrow->iaoq_back;
401 
402 	regs->sar  = pim_narrow->cr[11];
403 	regs->iir  = pim_narrow->cr[19];
404 	regs->isr  = pim_narrow->cr[20];
405 	regs->ior  = pim_narrow->cr[21];
406     }
407 
408     /*
409      * The following fields only have meaning if we came through
410      * another path. So just zero them here.
411      */
412 
413     regs->ksp = 0;
414     regs->kpc = 0;
415     regs->orig_r28 = 0;
416 }
417 
418 
419 /*
420  * This routine is called as a last resort when everything else
421  * has gone clearly wrong. We get called for faults in kernel space,
422  * and HPMC's.
423  */
424 void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long offset)
425 {
426 	static DEFINE_SPINLOCK(terminate_lock);
427 
428 	oops_in_progress = 1;
429 
430 	set_eiem(0);
431 	local_irq_disable();
432 	spin_lock(&terminate_lock);
433 
434 	/* unlock the pdc lock if necessary */
435 	pdc_emergency_unlock();
436 
437 	/* restart pdc console if necessary */
438 	if (!console_drivers)
439 		pdc_console_restart();
440 
441 	/* Not all paths will gutter the processor... */
442 	switch(code){
443 
444 	case 1:
445 		transfer_pim_to_trap_frame(regs);
446 		break;
447 
448 	default:
449 		/* Fall through */
450 		break;
451 
452 	}
453 
454 	{
455 		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
456 		struct unwind_frame_info info;
457 		unwind_frame_init(&info, current, regs);
458 		do_show_stack(&info);
459 	}
460 
461 	printk("\n");
462 	pr_crit("%s: Code=%d (%s) regs=%p (Addr=" RFMT ")\n",
463 		msg, code, trap_name(code), regs, offset);
464 	show_regs(regs);
465 
466 	spin_unlock(&terminate_lock);
467 
468 	/* put soft power button back under hardware control;
469 	 * if the user had pressed it once at any time, the
470 	 * system will shut down immediately right here. */
471 	pdc_soft_power_button(0);
472 
473 	/* Call kernel panic() so reboot timeouts work properly
474 	 * FIXME: This function should be on the list of
475 	 * panic notifiers, and we should call panic
476 	 * directly from the location that we wish.
477 	 * e.g. We should not call panic from
478 	 * parisc_terminate, but rather the oter way around.
479 	 * This hack works, prints the panic message twice,
480 	 * and it enables reboot timers!
481 	 */
482 	panic(msg);
483 }
484 
485 void notrace handle_interruption(int code, struct pt_regs *regs)
486 {
487 	unsigned long fault_address = 0;
488 	unsigned long fault_space = 0;
489 	struct siginfo si;
490 
491 	if (code == 1)
492 	    pdc_console_restart();  /* switch back to pdc if HPMC */
493 	else
494 	    local_irq_enable();
495 
496 	/* Security check:
497 	 * If the priority level is still user, and the
498 	 * faulting space is not equal to the active space
499 	 * then the user is attempting something in a space
500 	 * that does not belong to them. Kill the process.
501 	 *
502 	 * This is normally the situation when the user
503 	 * attempts to jump into the kernel space at the
504 	 * wrong offset, be it at the gateway page or a
505 	 * random location.
506 	 *
507 	 * We cannot normally signal the process because it
508 	 * could *be* on the gateway page, and processes
509 	 * executing on the gateway page can't have signals
510 	 * delivered.
511 	 *
512 	 * We merely readjust the address into the users
513 	 * space, at a destination address of zero, and
514 	 * allow processing to continue.
515 	 */
516 	if (((unsigned long)regs->iaoq[0] & 3) &&
517 	    ((unsigned long)regs->iasq[0] != (unsigned long)regs->sr[7])) {
518 		/* Kill the user process later */
519 		regs->iaoq[0] = 0 | 3;
520 		regs->iaoq[1] = regs->iaoq[0] + 4;
521 		regs->iasq[0] = regs->iasq[1] = regs->sr[7];
522 		regs->gr[0] &= ~PSW_B;
523 		return;
524 	}
525 
526 #if 0
527 	printk(KERN_CRIT "Interruption # %d\n", code);
528 #endif
529 
530 	switch(code) {
531 
532 	case  1:
533 		/* High-priority machine check (HPMC) */
534 
535 		/* set up a new led state on systems shipped with a LED State panel */
536 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_HPMC);
537 
538 		parisc_terminate("High Priority Machine Check (HPMC)",
539 				regs, code, 0);
540 		/* NOT REACHED */
541 
542 	case  2:
543 		/* Power failure interrupt */
544 		printk(KERN_CRIT "Power failure interrupt !\n");
545 		return;
546 
547 	case  3:
548 		/* Recovery counter trap */
549 		regs->gr[0] &= ~PSW_R;
550 		if (user_space(regs))
551 			handle_gdb_break(regs, TRAP_TRACE);
552 		/* else this must be the start of a syscall - just let it run */
553 		return;
554 
555 	case  5:
556 		/* Low-priority machine check */
557 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_LPMC);
558 
559 		flush_cache_all();
560 		flush_tlb_all();
561 		cpu_lpmc(5, regs);
562 		return;
563 
564 	case  6:
565 		/* Instruction TLB miss fault/Instruction page fault */
566 		fault_address = regs->iaoq[0];
567 		fault_space   = regs->iasq[0];
568 		break;
569 
570 	case  8:
571 		/* Illegal instruction trap */
572 		die_if_kernel("Illegal instruction", regs, code);
573 		si.si_code = ILL_ILLOPC;
574 		goto give_sigill;
575 
576 	case  9:
577 		/* Break instruction trap */
578 		handle_break(regs);
579 		return;
580 
581 	case 10:
582 		/* Privileged operation trap */
583 		die_if_kernel("Privileged operation", regs, code);
584 		si.si_code = ILL_PRVOPC;
585 		goto give_sigill;
586 
587 	case 11:
588 		/* Privileged register trap */
589 		if ((regs->iir & 0xffdfffe0) == 0x034008a0) {
590 
591 			/* This is a MFCTL cr26/cr27 to gr instruction.
592 			 * PCXS traps on this, so we need to emulate it.
593 			 */
594 
595 			if (regs->iir & 0x00200000)
596 				regs->gr[regs->iir & 0x1f] = mfctl(27);
597 			else
598 				regs->gr[regs->iir & 0x1f] = mfctl(26);
599 
600 			regs->iaoq[0] = regs->iaoq[1];
601 			regs->iaoq[1] += 4;
602 			regs->iasq[0] = regs->iasq[1];
603 			return;
604 		}
605 
606 		die_if_kernel("Privileged register usage", regs, code);
607 		si.si_code = ILL_PRVREG;
608 	give_sigill:
609 		si.si_signo = SIGILL;
610 		si.si_errno = 0;
611 		si.si_addr = (void __user *) regs->iaoq[0];
612 		force_sig_info(SIGILL, &si, current);
613 		return;
614 
615 	case 12:
616 		/* Overflow Trap, let the userland signal handler do the cleanup */
617 		si.si_signo = SIGFPE;
618 		si.si_code = FPE_INTOVF;
619 		si.si_addr = (void __user *) regs->iaoq[0];
620 		force_sig_info(SIGFPE, &si, current);
621 		return;
622 
623 	case 13:
624 		/* Conditional Trap
625 		   The condition succeeds in an instruction which traps
626 		   on condition  */
627 		if(user_mode(regs)){
628 			si.si_signo = SIGFPE;
629 			/* Set to zero, and let the userspace app figure it out from
630 			   the insn pointed to by si_addr */
631 			si.si_code = 0;
632 			si.si_addr = (void __user *) regs->iaoq[0];
633 			force_sig_info(SIGFPE, &si, current);
634 			return;
635 		}
636 		/* The kernel doesn't want to handle condition codes */
637 		break;
638 
639 	case 14:
640 		/* Assist Exception Trap, i.e. floating point exception. */
641 		die_if_kernel("Floating point exception", regs, 0); /* quiet */
642 		__inc_irq_stat(irq_fpassist_count);
643 		handle_fpe(regs);
644 		return;
645 
646 	case 15:
647 		/* Data TLB miss fault/Data page fault */
648 		/* Fall through */
649 	case 16:
650 		/* Non-access instruction TLB miss fault */
651 		/* The instruction TLB entry needed for the target address of the FIC
652 		   is absent, and hardware can't find it, so we get to cleanup */
653 		/* Fall through */
654 	case 17:
655 		/* Non-access data TLB miss fault/Non-access data page fault */
656 		/* FIXME:
657 			 Still need to add slow path emulation code here!
658 			 If the insn used a non-shadow register, then the tlb
659 			 handlers could not have their side-effect (e.g. probe
660 			 writing to a target register) emulated since rfir would
661 			 erase the changes to said register. Instead we have to
662 			 setup everything, call this function we are in, and emulate
663 			 by hand. Technically we need to emulate:
664 			 fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw
665 		*/
666 		fault_address = regs->ior;
667 		fault_space = regs->isr;
668 		break;
669 
670 	case 18:
671 		/* PCXS only -- later cpu's split this into types 26,27 & 28 */
672 		/* Check for unaligned access */
673 		if (check_unaligned(regs)) {
674 			handle_unaligned(regs);
675 			return;
676 		}
677 		/* Fall Through */
678 	case 26:
679 		/* PCXL: Data memory access rights trap */
680 		fault_address = regs->ior;
681 		fault_space   = regs->isr;
682 		break;
683 
684 	case 19:
685 		/* Data memory break trap */
686 		regs->gr[0] |= PSW_X; /* So we can single-step over the trap */
687 		/* fall thru */
688 	case 21:
689 		/* Page reference trap */
690 		handle_gdb_break(regs, TRAP_HWBKPT);
691 		return;
692 
693 	case 25:
694 		/* Taken branch trap */
695 		regs->gr[0] &= ~PSW_T;
696 		if (user_space(regs))
697 			handle_gdb_break(regs, TRAP_BRANCH);
698 		/* else this must be the start of a syscall - just let it
699 		 * run.
700 		 */
701 		return;
702 
703 	case  7:
704 		/* Instruction access rights */
705 		/* PCXL: Instruction memory protection trap */
706 
707 		/*
708 		 * This could be caused by either: 1) a process attempting
709 		 * to execute within a vma that does not have execute
710 		 * permission, or 2) an access rights violation caused by a
711 		 * flush only translation set up by ptep_get_and_clear().
712 		 * So we check the vma permissions to differentiate the two.
713 		 * If the vma indicates we have execute permission, then
714 		 * the cause is the latter one. In this case, we need to
715 		 * call do_page_fault() to fix the problem.
716 		 */
717 
718 		if (user_mode(regs)) {
719 			struct vm_area_struct *vma;
720 
721 			down_read(&current->mm->mmap_sem);
722 			vma = find_vma(current->mm,regs->iaoq[0]);
723 			if (vma && (regs->iaoq[0] >= vma->vm_start)
724 				&& (vma->vm_flags & VM_EXEC)) {
725 
726 				fault_address = regs->iaoq[0];
727 				fault_space = regs->iasq[0];
728 
729 				up_read(&current->mm->mmap_sem);
730 				break; /* call do_page_fault() */
731 			}
732 			up_read(&current->mm->mmap_sem);
733 		}
734 		/* Fall Through */
735 	case 27:
736 		/* Data memory protection ID trap */
737 		if (code == 27 && !user_mode(regs) &&
738 			fixup_exception(regs))
739 			return;
740 
741 		die_if_kernel("Protection id trap", regs, code);
742 		si.si_code = SEGV_MAPERR;
743 		si.si_signo = SIGSEGV;
744 		si.si_errno = 0;
745 		if (code == 7)
746 		    si.si_addr = (void __user *) regs->iaoq[0];
747 		else
748 		    si.si_addr = (void __user *) regs->ior;
749 		force_sig_info(SIGSEGV, &si, current);
750 		return;
751 
752 	case 28:
753 		/* Unaligned data reference trap */
754 		handle_unaligned(regs);
755 		return;
756 
757 	default:
758 		if (user_mode(regs)) {
759 			parisc_printk_ratelimited(0, regs, KERN_DEBUG
760 				"handle_interruption() pid=%d command='%s'\n",
761 				task_pid_nr(current), current->comm);
762 			/* SIGBUS, for lack of a better one. */
763 			si.si_signo = SIGBUS;
764 			si.si_code = BUS_OBJERR;
765 			si.si_errno = 0;
766 			si.si_addr = (void __user *) regs->ior;
767 			force_sig_info(SIGBUS, &si, current);
768 			return;
769 		}
770 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
771 
772 		parisc_terminate("Unexpected interruption", regs, code, 0);
773 		/* NOT REACHED */
774 	}
775 
776 	if (user_mode(regs)) {
777 	    if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
778 		parisc_printk_ratelimited(0, regs, KERN_DEBUG
779 				"User fault %d on space 0x%08lx, pid=%d command='%s'\n",
780 				code, fault_space,
781 				task_pid_nr(current), current->comm);
782 		si.si_signo = SIGSEGV;
783 		si.si_errno = 0;
784 		si.si_code = SEGV_MAPERR;
785 		si.si_addr = (void __user *) regs->ior;
786 		force_sig_info(SIGSEGV, &si, current);
787 		return;
788 	    }
789 	}
790 	else {
791 
792 	    /*
793 	     * The kernel should never fault on its own address space,
794 	     * unless pagefault_disable() was called before.
795 	     */
796 
797 	    if (fault_space == 0 && !faulthandler_disabled())
798 	    {
799 		/* Clean up and return if in exception table. */
800 		if (fixup_exception(regs))
801 			return;
802 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
803 		parisc_terminate("Kernel Fault", regs, code, fault_address);
804 	    }
805 	}
806 
807 	do_page_fault(regs, code, fault_address);
808 }
809 
810 
811 void __init initialize_ivt(const void *iva)
812 {
813 	extern u32 os_hpmc_size;
814 	extern const u32 os_hpmc[];
815 
816 	int i;
817 	u32 check = 0;
818 	u32 *ivap;
819 	u32 *hpmcp;
820 	u32 length;
821 
822 	if (strcmp((const char *)iva, "cows can fly"))
823 		panic("IVT invalid");
824 
825 	ivap = (u32 *)iva;
826 
827 	for (i = 0; i < 8; i++)
828 	    *ivap++ = 0;
829 
830 	/* Compute Checksum for HPMC handler */
831 	length = os_hpmc_size;
832 	ivap[7] = length;
833 
834 	hpmcp = (u32 *)os_hpmc;
835 
836 	for (i=0; i<length/4; i++)
837 	    check += *hpmcp++;
838 
839 	for (i=0; i<8; i++)
840 	    check += ivap[i];
841 
842 	ivap[5] = -check;
843 }
844 
845 
846 /* early_trap_init() is called before we set up kernel mappings and
847  * write-protect the kernel */
848 void  __init early_trap_init(void)
849 {
850 	extern const void fault_vector_20;
851 
852 #ifndef CONFIG_64BIT
853 	extern const void fault_vector_11;
854 	initialize_ivt(&fault_vector_11);
855 #endif
856 
857 	initialize_ivt(&fault_vector_20);
858 }
859 
860 void __init trap_init(void)
861 {
862 }
863