xref: /openbmc/linux/arch/parisc/kernel/traps.c (revision 9cfc5c90)
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/kernel.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/ptrace.h>
18 #include <linux/timer.h>
19 #include <linux/delay.h>
20 #include <linux/mm.h>
21 #include <linux/module.h>
22 #include <linux/smp.h>
23 #include <linux/spinlock.h>
24 #include <linux/init.h>
25 #include <linux/interrupt.h>
26 #include <linux/console.h>
27 #include <linux/bug.h>
28 #include <linux/ratelimit.h>
29 #include <linux/uaccess.h>
30 
31 #include <asm/assembly.h>
32 #include <asm/io.h>
33 #include <asm/irq.h>
34 #include <asm/traps.h>
35 #include <asm/unaligned.h>
36 #include <linux/atomic.h>
37 #include <asm/smp.h>
38 #include <asm/pdc.h>
39 #include <asm/pdc_chassis.h>
40 #include <asm/unwind.h>
41 #include <asm/tlbflush.h>
42 #include <asm/cacheflush.h>
43 
44 #include "../math-emu/math-emu.h"	/* for handle_fpe() */
45 
46 static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
47 	struct pt_regs *regs);
48 
49 static int printbinary(char *buf, unsigned long x, int nbits)
50 {
51 	unsigned long mask = 1UL << (nbits - 1);
52 	while (mask != 0) {
53 		*buf++ = (mask & x ? '1' : '0');
54 		mask >>= 1;
55 	}
56 	*buf = '\0';
57 
58 	return nbits;
59 }
60 
61 #ifdef CONFIG_64BIT
62 #define RFMT "%016lx"
63 #else
64 #define RFMT "%08lx"
65 #endif
66 #define FFMT "%016llx"	/* fpregs are 64-bit always */
67 
68 #define PRINTREGS(lvl,r,f,fmt,x)	\
69 	printk("%s%s%02d-%02d  " fmt " " fmt " " fmt " " fmt "\n",	\
70 		lvl, f, (x), (x+3), (r)[(x)+0], (r)[(x)+1],		\
71 		(r)[(x)+2], (r)[(x)+3])
72 
73 static void print_gr(char *level, struct pt_regs *regs)
74 {
75 	int i;
76 	char buf[64];
77 
78 	printk("%s\n", level);
79 	printk("%s     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI\n", level);
80 	printbinary(buf, regs->gr[0], 32);
81 	printk("%sPSW: %s %s\n", level, buf, print_tainted());
82 
83 	for (i = 0; i < 32; i += 4)
84 		PRINTREGS(level, regs->gr, "r", RFMT, i);
85 }
86 
87 static void print_fr(char *level, struct pt_regs *regs)
88 {
89 	int i;
90 	char buf[64];
91 	struct { u32 sw[2]; } s;
92 
93 	/* FR are 64bit everywhere. Need to use asm to get the content
94 	 * of fpsr/fper1, and we assume that we won't have a FP Identify
95 	 * in our way, otherwise we're screwed.
96 	 * The fldd is used to restore the T-bit if there was one, as the
97 	 * store clears it anyway.
98 	 * PA2.0 book says "thou shall not use fstw on FPSR/FPERs" - T-Bone */
99 	asm volatile ("fstd %%fr0,0(%1)	\n\t"
100 		      "fldd 0(%1),%%fr0	\n\t"
101 		      : "=m" (s) : "r" (&s) : "r0");
102 
103 	printk("%s\n", level);
104 	printk("%s      VZOUICununcqcqcqcqcqcrmunTDVZOUI\n", level);
105 	printbinary(buf, s.sw[0], 32);
106 	printk("%sFPSR: %s\n", level, buf);
107 	printk("%sFPER1: %08x\n", level, s.sw[1]);
108 
109 	/* here we'll print fr0 again, tho it'll be meaningless */
110 	for (i = 0; i < 32; i += 4)
111 		PRINTREGS(level, regs->fr, "fr", FFMT, i);
112 }
113 
114 void show_regs(struct pt_regs *regs)
115 {
116 	int i, user;
117 	char *level;
118 	unsigned long cr30, cr31;
119 
120 	user = user_mode(regs);
121 	level = user ? KERN_DEBUG : KERN_CRIT;
122 
123 	show_regs_print_info(level);
124 
125 	print_gr(level, regs);
126 
127 	for (i = 0; i < 8; i += 4)
128 		PRINTREGS(level, regs->sr, "sr", RFMT, i);
129 
130 	if (user)
131 		print_fr(level, regs);
132 
133 	cr30 = mfctl(30);
134 	cr31 = mfctl(31);
135 	printk("%s\n", level);
136 	printk("%sIASQ: " RFMT " " RFMT " IAOQ: " RFMT " " RFMT "\n",
137 	       level, regs->iasq[0], regs->iasq[1], regs->iaoq[0], regs->iaoq[1]);
138 	printk("%s IIR: %08lx    ISR: " RFMT "  IOR: " RFMT "\n",
139 	       level, regs->iir, regs->isr, regs->ior);
140 	printk("%s CPU: %8d   CR30: " RFMT " CR31: " RFMT "\n",
141 	       level, current_thread_info()->cpu, cr30, cr31);
142 	printk("%s ORIG_R28: " RFMT "\n", level, regs->orig_r28);
143 
144 	if (user) {
145 		printk("%s IAOQ[0]: " RFMT "\n", level, regs->iaoq[0]);
146 		printk("%s IAOQ[1]: " RFMT "\n", level, regs->iaoq[1]);
147 		printk("%s RP(r2): " RFMT "\n", level, regs->gr[2]);
148 	} else {
149 		printk("%s IAOQ[0]: %pS\n", level, (void *) regs->iaoq[0]);
150 		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
151 		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
152 
153 		parisc_show_stack(current, NULL, regs);
154 	}
155 }
156 
157 static DEFINE_RATELIMIT_STATE(_hppa_rs,
158 	DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST);
159 
160 #define parisc_printk_ratelimited(critical, regs, fmt, ...)	{	      \
161 	if ((critical || show_unhandled_signals) && __ratelimit(&_hppa_rs)) { \
162 		printk(fmt, ##__VA_ARGS__);				      \
163 		show_regs(regs);					      \
164 	}								      \
165 }
166 
167 
168 static void do_show_stack(struct unwind_frame_info *info)
169 {
170 	int i = 1;
171 
172 	printk(KERN_CRIT "Backtrace:\n");
173 	while (i <= 16) {
174 		if (unwind_once(info) < 0 || info->ip == 0)
175 			break;
176 
177 		if (__kernel_text_address(info->ip)) {
178 			printk(KERN_CRIT " [<" RFMT ">] %pS\n",
179 				info->ip, (void *) info->ip);
180 			i++;
181 		}
182 	}
183 	printk(KERN_CRIT "\n");
184 }
185 
186 static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
187 	struct pt_regs *regs)
188 {
189 	struct unwind_frame_info info;
190 	struct task_struct *t;
191 
192 	t = task ? task : current;
193 	if (regs) {
194 		unwind_frame_init(&info, t, regs);
195 		goto show_stack;
196 	}
197 
198 	if (t == current) {
199 		unsigned long sp;
200 
201 HERE:
202 		asm volatile ("copy %%r30, %0" : "=r"(sp));
203 		{
204 			struct pt_regs r;
205 
206 			memset(&r, 0, sizeof(struct pt_regs));
207 			r.iaoq[0] = (unsigned long)&&HERE;
208 			r.gr[2] = (unsigned long)__builtin_return_address(0);
209 			r.gr[30] = sp;
210 
211 			unwind_frame_init(&info, current, &r);
212 		}
213 	} else {
214 		unwind_frame_init_from_blocked_task(&info, t);
215 	}
216 
217 show_stack:
218 	do_show_stack(&info);
219 }
220 
221 void show_stack(struct task_struct *t, unsigned long *sp)
222 {
223 	return parisc_show_stack(t, sp, NULL);
224 }
225 
226 int is_valid_bugaddr(unsigned long iaoq)
227 {
228 	return 1;
229 }
230 
231 void die_if_kernel(char *str, struct pt_regs *regs, long err)
232 {
233 	if (user_mode(regs)) {
234 		if (err == 0)
235 			return; /* STFU */
236 
237 		parisc_printk_ratelimited(1, regs,
238 			KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
239 			current->comm, task_pid_nr(current), str, err, regs->iaoq[0]);
240 
241 		return;
242 	}
243 
244 	oops_in_progress = 1;
245 
246 	oops_enter();
247 
248 	/* Amuse the user in a SPARC fashion */
249 	if (err) printk(KERN_CRIT
250 			"      _______________________________ \n"
251 			"     < Your System ate a SPARC! Gah! >\n"
252 			"      ------------------------------- \n"
253 			"             \\   ^__^\n"
254 			"                 (__)\\       )\\/\\\n"
255 			"                  U  ||----w |\n"
256 			"                     ||     ||\n");
257 
258 	/* unlock the pdc lock if necessary */
259 	pdc_emergency_unlock();
260 
261 	/* maybe the kernel hasn't booted very far yet and hasn't been able
262 	 * to initialize the serial or STI console. In that case we should
263 	 * re-enable the pdc console, so that the user will be able to
264 	 * identify the problem. */
265 	if (!console_drivers)
266 		pdc_console_restart();
267 
268 	if (err)
269 		printk(KERN_CRIT "%s (pid %d): %s (code %ld)\n",
270 			current->comm, task_pid_nr(current), str, err);
271 
272 	/* Wot's wrong wif bein' racy? */
273 	if (current->thread.flags & PARISC_KERNEL_DEATH) {
274 		printk(KERN_CRIT "%s() recursion detected.\n", __func__);
275 		local_irq_enable();
276 		while (1);
277 	}
278 	current->thread.flags |= PARISC_KERNEL_DEATH;
279 
280 	show_regs(regs);
281 	dump_stack();
282 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
283 
284 	if (in_interrupt())
285 		panic("Fatal exception in interrupt");
286 
287 	if (panic_on_oops) {
288 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
289 		ssleep(5);
290 		panic("Fatal exception");
291 	}
292 
293 	oops_exit();
294 	do_exit(SIGSEGV);
295 }
296 
297 /* gdb uses break 4,8 */
298 #define GDB_BREAK_INSN 0x10004
299 static void handle_gdb_break(struct pt_regs *regs, int wot)
300 {
301 	struct siginfo si;
302 
303 	si.si_signo = SIGTRAP;
304 	si.si_errno = 0;
305 	si.si_code = wot;
306 	si.si_addr = (void __user *) (regs->iaoq[0] & ~3);
307 	force_sig_info(SIGTRAP, &si, current);
308 }
309 
310 static void handle_break(struct pt_regs *regs)
311 {
312 	unsigned iir = regs->iir;
313 
314 	if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
315 		/* check if a BUG() or WARN() trapped here.  */
316 		enum bug_trap_type tt;
317 		tt = report_bug(regs->iaoq[0] & ~3, regs);
318 		if (tt == BUG_TRAP_TYPE_WARN) {
319 			regs->iaoq[0] += 4;
320 			regs->iaoq[1] += 4;
321 			return; /* return to next instruction when WARN_ON().  */
322 		}
323 		die_if_kernel("Unknown kernel breakpoint", regs,
324 			(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
325 	}
326 
327 	if (unlikely(iir != GDB_BREAK_INSN))
328 		parisc_printk_ratelimited(0, regs,
329 			KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
330 			iir & 31, (iir>>13) & ((1<<13)-1),
331 			task_pid_nr(current), current->comm);
332 
333 	/* send standard GDB signal */
334 	handle_gdb_break(regs, TRAP_BRKPT);
335 }
336 
337 static void default_trap(int code, struct pt_regs *regs)
338 {
339 	printk(KERN_ERR "Trap %d on CPU %d\n", code, smp_processor_id());
340 	show_regs(regs);
341 }
342 
343 void (*cpu_lpmc) (int code, struct pt_regs *regs) __read_mostly = default_trap;
344 
345 
346 void transfer_pim_to_trap_frame(struct pt_regs *regs)
347 {
348     register int i;
349     extern unsigned int hpmc_pim_data[];
350     struct pdc_hpmc_pim_11 *pim_narrow;
351     struct pdc_hpmc_pim_20 *pim_wide;
352 
353     if (boot_cpu_data.cpu_type >= pcxu) {
354 
355 	pim_wide = (struct pdc_hpmc_pim_20 *)hpmc_pim_data;
356 
357 	/*
358 	 * Note: The following code will probably generate a
359 	 * bunch of truncation error warnings from the compiler.
360 	 * Could be handled with an ifdef, but perhaps there
361 	 * is a better way.
362 	 */
363 
364 	regs->gr[0] = pim_wide->cr[22];
365 
366 	for (i = 1; i < 32; i++)
367 	    regs->gr[i] = pim_wide->gr[i];
368 
369 	for (i = 0; i < 32; i++)
370 	    regs->fr[i] = pim_wide->fr[i];
371 
372 	for (i = 0; i < 8; i++)
373 	    regs->sr[i] = pim_wide->sr[i];
374 
375 	regs->iasq[0] = pim_wide->cr[17];
376 	regs->iasq[1] = pim_wide->iasq_back;
377 	regs->iaoq[0] = pim_wide->cr[18];
378 	regs->iaoq[1] = pim_wide->iaoq_back;
379 
380 	regs->sar  = pim_wide->cr[11];
381 	regs->iir  = pim_wide->cr[19];
382 	regs->isr  = pim_wide->cr[20];
383 	regs->ior  = pim_wide->cr[21];
384     }
385     else {
386 	pim_narrow = (struct pdc_hpmc_pim_11 *)hpmc_pim_data;
387 
388 	regs->gr[0] = pim_narrow->cr[22];
389 
390 	for (i = 1; i < 32; i++)
391 	    regs->gr[i] = pim_narrow->gr[i];
392 
393 	for (i = 0; i < 32; i++)
394 	    regs->fr[i] = pim_narrow->fr[i];
395 
396 	for (i = 0; i < 8; i++)
397 	    regs->sr[i] = pim_narrow->sr[i];
398 
399 	regs->iasq[0] = pim_narrow->cr[17];
400 	regs->iasq[1] = pim_narrow->iasq_back;
401 	regs->iaoq[0] = pim_narrow->cr[18];
402 	regs->iaoq[1] = pim_narrow->iaoq_back;
403 
404 	regs->sar  = pim_narrow->cr[11];
405 	regs->iir  = pim_narrow->cr[19];
406 	regs->isr  = pim_narrow->cr[20];
407 	regs->ior  = pim_narrow->cr[21];
408     }
409 
410     /*
411      * The following fields only have meaning if we came through
412      * another path. So just zero them here.
413      */
414 
415     regs->ksp = 0;
416     regs->kpc = 0;
417     regs->orig_r28 = 0;
418 }
419 
420 
421 /*
422  * This routine is called as a last resort when everything else
423  * has gone clearly wrong. We get called for faults in kernel space,
424  * and HPMC's.
425  */
426 void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long offset)
427 {
428 	static DEFINE_SPINLOCK(terminate_lock);
429 
430 	oops_in_progress = 1;
431 
432 	set_eiem(0);
433 	local_irq_disable();
434 	spin_lock(&terminate_lock);
435 
436 	/* unlock the pdc lock if necessary */
437 	pdc_emergency_unlock();
438 
439 	/* restart pdc console if necessary */
440 	if (!console_drivers)
441 		pdc_console_restart();
442 
443 	/* Not all paths will gutter the processor... */
444 	switch(code){
445 
446 	case 1:
447 		transfer_pim_to_trap_frame(regs);
448 		break;
449 
450 	default:
451 		/* Fall through */
452 		break;
453 
454 	}
455 
456 	{
457 		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
458 		struct unwind_frame_info info;
459 		unwind_frame_init(&info, current, regs);
460 		do_show_stack(&info);
461 	}
462 
463 	printk("\n");
464 	printk(KERN_CRIT "%s: Code=%d regs=%p (Addr=" RFMT ")\n",
465 			msg, code, regs, offset);
466 	show_regs(regs);
467 
468 	spin_unlock(&terminate_lock);
469 
470 	/* put soft power button back under hardware control;
471 	 * if the user had pressed it once at any time, the
472 	 * system will shut down immediately right here. */
473 	pdc_soft_power_button(0);
474 
475 	/* Call kernel panic() so reboot timeouts work properly
476 	 * FIXME: This function should be on the list of
477 	 * panic notifiers, and we should call panic
478 	 * directly from the location that we wish.
479 	 * e.g. We should not call panic from
480 	 * parisc_terminate, but rather the oter way around.
481 	 * This hack works, prints the panic message twice,
482 	 * and it enables reboot timers!
483 	 */
484 	panic(msg);
485 }
486 
487 void notrace handle_interruption(int code, struct pt_regs *regs)
488 {
489 	unsigned long fault_address = 0;
490 	unsigned long fault_space = 0;
491 	struct siginfo si;
492 
493 	if (code == 1)
494 	    pdc_console_restart();  /* switch back to pdc if HPMC */
495 	else
496 	    local_irq_enable();
497 
498 	/* Security check:
499 	 * If the priority level is still user, and the
500 	 * faulting space is not equal to the active space
501 	 * then the user is attempting something in a space
502 	 * that does not belong to them. Kill the process.
503 	 *
504 	 * This is normally the situation when the user
505 	 * attempts to jump into the kernel space at the
506 	 * wrong offset, be it at the gateway page or a
507 	 * random location.
508 	 *
509 	 * We cannot normally signal the process because it
510 	 * could *be* on the gateway page, and processes
511 	 * executing on the gateway page can't have signals
512 	 * delivered.
513 	 *
514 	 * We merely readjust the address into the users
515 	 * space, at a destination address of zero, and
516 	 * allow processing to continue.
517 	 */
518 	if (((unsigned long)regs->iaoq[0] & 3) &&
519 	    ((unsigned long)regs->iasq[0] != (unsigned long)regs->sr[7])) {
520 		/* Kill the user process later */
521 		regs->iaoq[0] = 0 | 3;
522 		regs->iaoq[1] = regs->iaoq[0] + 4;
523 		regs->iasq[0] = regs->iasq[1] = regs->sr[7];
524 		regs->gr[0] &= ~PSW_B;
525 		return;
526 	}
527 
528 #if 0
529 	printk(KERN_CRIT "Interruption # %d\n", code);
530 #endif
531 
532 	switch(code) {
533 
534 	case  1:
535 		/* High-priority machine check (HPMC) */
536 
537 		/* set up a new led state on systems shipped with a LED State panel */
538 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_HPMC);
539 
540 		parisc_terminate("High Priority Machine Check (HPMC)",
541 				regs, code, 0);
542 		/* NOT REACHED */
543 
544 	case  2:
545 		/* Power failure interrupt */
546 		printk(KERN_CRIT "Power failure interrupt !\n");
547 		return;
548 
549 	case  3:
550 		/* Recovery counter trap */
551 		regs->gr[0] &= ~PSW_R;
552 		if (user_space(regs))
553 			handle_gdb_break(regs, TRAP_TRACE);
554 		/* else this must be the start of a syscall - just let it run */
555 		return;
556 
557 	case  5:
558 		/* Low-priority machine check */
559 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_LPMC);
560 
561 		flush_cache_all();
562 		flush_tlb_all();
563 		cpu_lpmc(5, regs);
564 		return;
565 
566 	case  6:
567 		/* Instruction TLB miss fault/Instruction page fault */
568 		fault_address = regs->iaoq[0];
569 		fault_space   = regs->iasq[0];
570 		break;
571 
572 	case  8:
573 		/* Illegal instruction trap */
574 		die_if_kernel("Illegal instruction", regs, code);
575 		si.si_code = ILL_ILLOPC;
576 		goto give_sigill;
577 
578 	case  9:
579 		/* Break instruction trap */
580 		handle_break(regs);
581 		return;
582 
583 	case 10:
584 		/* Privileged operation trap */
585 		die_if_kernel("Privileged operation", regs, code);
586 		si.si_code = ILL_PRVOPC;
587 		goto give_sigill;
588 
589 	case 11:
590 		/* Privileged register trap */
591 		if ((regs->iir & 0xffdfffe0) == 0x034008a0) {
592 
593 			/* This is a MFCTL cr26/cr27 to gr instruction.
594 			 * PCXS traps on this, so we need to emulate it.
595 			 */
596 
597 			if (regs->iir & 0x00200000)
598 				regs->gr[regs->iir & 0x1f] = mfctl(27);
599 			else
600 				regs->gr[regs->iir & 0x1f] = mfctl(26);
601 
602 			regs->iaoq[0] = regs->iaoq[1];
603 			regs->iaoq[1] += 4;
604 			regs->iasq[0] = regs->iasq[1];
605 			return;
606 		}
607 
608 		die_if_kernel("Privileged register usage", regs, code);
609 		si.si_code = ILL_PRVREG;
610 	give_sigill:
611 		si.si_signo = SIGILL;
612 		si.si_errno = 0;
613 		si.si_addr = (void __user *) regs->iaoq[0];
614 		force_sig_info(SIGILL, &si, current);
615 		return;
616 
617 	case 12:
618 		/* Overflow Trap, let the userland signal handler do the cleanup */
619 		si.si_signo = SIGFPE;
620 		si.si_code = FPE_INTOVF;
621 		si.si_addr = (void __user *) regs->iaoq[0];
622 		force_sig_info(SIGFPE, &si, current);
623 		return;
624 
625 	case 13:
626 		/* Conditional Trap
627 		   The condition succeeds in an instruction which traps
628 		   on condition  */
629 		if(user_mode(regs)){
630 			si.si_signo = SIGFPE;
631 			/* Set to zero, and let the userspace app figure it out from
632 			   the insn pointed to by si_addr */
633 			si.si_code = 0;
634 			si.si_addr = (void __user *) regs->iaoq[0];
635 			force_sig_info(SIGFPE, &si, current);
636 			return;
637 		}
638 		/* The kernel doesn't want to handle condition codes */
639 		break;
640 
641 	case 14:
642 		/* Assist Exception Trap, i.e. floating point exception. */
643 		die_if_kernel("Floating point exception", regs, 0); /* quiet */
644 		__inc_irq_stat(irq_fpassist_count);
645 		handle_fpe(regs);
646 		return;
647 
648 	case 15:
649 		/* Data TLB miss fault/Data page fault */
650 		/* Fall through */
651 	case 16:
652 		/* Non-access instruction TLB miss fault */
653 		/* The instruction TLB entry needed for the target address of the FIC
654 		   is absent, and hardware can't find it, so we get to cleanup */
655 		/* Fall through */
656 	case 17:
657 		/* Non-access data TLB miss fault/Non-access data page fault */
658 		/* FIXME:
659 			 Still need to add slow path emulation code here!
660 			 If the insn used a non-shadow register, then the tlb
661 			 handlers could not have their side-effect (e.g. probe
662 			 writing to a target register) emulated since rfir would
663 			 erase the changes to said register. Instead we have to
664 			 setup everything, call this function we are in, and emulate
665 			 by hand. Technically we need to emulate:
666 			 fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw
667 		*/
668 		fault_address = regs->ior;
669 		fault_space = regs->isr;
670 		break;
671 
672 	case 18:
673 		/* PCXS only -- later cpu's split this into types 26,27 & 28 */
674 		/* Check for unaligned access */
675 		if (check_unaligned(regs)) {
676 			handle_unaligned(regs);
677 			return;
678 		}
679 		/* Fall Through */
680 	case 26:
681 		/* PCXL: Data memory access rights trap */
682 		fault_address = regs->ior;
683 		fault_space   = regs->isr;
684 		break;
685 
686 	case 19:
687 		/* Data memory break trap */
688 		regs->gr[0] |= PSW_X; /* So we can single-step over the trap */
689 		/* fall thru */
690 	case 21:
691 		/* Page reference trap */
692 		handle_gdb_break(regs, TRAP_HWBKPT);
693 		return;
694 
695 	case 25:
696 		/* Taken branch trap */
697 		regs->gr[0] &= ~PSW_T;
698 		if (user_space(regs))
699 			handle_gdb_break(regs, TRAP_BRANCH);
700 		/* else this must be the start of a syscall - just let it
701 		 * run.
702 		 */
703 		return;
704 
705 	case  7:
706 		/* Instruction access rights */
707 		/* PCXL: Instruction memory protection trap */
708 
709 		/*
710 		 * This could be caused by either: 1) a process attempting
711 		 * to execute within a vma that does not have execute
712 		 * permission, or 2) an access rights violation caused by a
713 		 * flush only translation set up by ptep_get_and_clear().
714 		 * So we check the vma permissions to differentiate the two.
715 		 * If the vma indicates we have execute permission, then
716 		 * the cause is the latter one. In this case, we need to
717 		 * call do_page_fault() to fix the problem.
718 		 */
719 
720 		if (user_mode(regs)) {
721 			struct vm_area_struct *vma;
722 
723 			down_read(&current->mm->mmap_sem);
724 			vma = find_vma(current->mm,regs->iaoq[0]);
725 			if (vma && (regs->iaoq[0] >= vma->vm_start)
726 				&& (vma->vm_flags & VM_EXEC)) {
727 
728 				fault_address = regs->iaoq[0];
729 				fault_space = regs->iasq[0];
730 
731 				up_read(&current->mm->mmap_sem);
732 				break; /* call do_page_fault() */
733 			}
734 			up_read(&current->mm->mmap_sem);
735 		}
736 		/* Fall Through */
737 	case 27:
738 		/* Data memory protection ID trap */
739 		if (code == 27 && !user_mode(regs) &&
740 			fixup_exception(regs))
741 			return;
742 
743 		die_if_kernel("Protection id trap", regs, code);
744 		si.si_code = SEGV_MAPERR;
745 		si.si_signo = SIGSEGV;
746 		si.si_errno = 0;
747 		if (code == 7)
748 		    si.si_addr = (void __user *) regs->iaoq[0];
749 		else
750 		    si.si_addr = (void __user *) regs->ior;
751 		force_sig_info(SIGSEGV, &si, current);
752 		return;
753 
754 	case 28:
755 		/* Unaligned data reference trap */
756 		handle_unaligned(regs);
757 		return;
758 
759 	default:
760 		if (user_mode(regs)) {
761 			parisc_printk_ratelimited(0, regs, KERN_DEBUG
762 				"handle_interruption() pid=%d command='%s'\n",
763 				task_pid_nr(current), current->comm);
764 			/* SIGBUS, for lack of a better one. */
765 			si.si_signo = SIGBUS;
766 			si.si_code = BUS_OBJERR;
767 			si.si_errno = 0;
768 			si.si_addr = (void __user *) regs->ior;
769 			force_sig_info(SIGBUS, &si, current);
770 			return;
771 		}
772 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
773 
774 		parisc_terminate("Unexpected interruption", regs, code, 0);
775 		/* NOT REACHED */
776 	}
777 
778 	if (user_mode(regs)) {
779 	    if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
780 		parisc_printk_ratelimited(0, regs, KERN_DEBUG
781 				"User fault %d on space 0x%08lx, pid=%d command='%s'\n",
782 				code, fault_space,
783 				task_pid_nr(current), current->comm);
784 		si.si_signo = SIGSEGV;
785 		si.si_errno = 0;
786 		si.si_code = SEGV_MAPERR;
787 		si.si_addr = (void __user *) regs->ior;
788 		force_sig_info(SIGSEGV, &si, current);
789 		return;
790 	    }
791 	}
792 	else {
793 
794 	    /*
795 	     * The kernel should never fault on its own address space,
796 	     * unless pagefault_disable() was called before.
797 	     */
798 
799 	    if (fault_space == 0 && !faulthandler_disabled())
800 	    {
801 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
802 		parisc_terminate("Kernel Fault", regs, code, fault_address);
803 	    }
804 	}
805 
806 	do_page_fault(regs, code, fault_address);
807 }
808 
809 
810 int __init check_ivt(void *iva)
811 {
812 	extern u32 os_hpmc_size;
813 	extern const u32 os_hpmc[];
814 
815 	int i;
816 	u32 check = 0;
817 	u32 *ivap;
818 	u32 *hpmcp;
819 	u32 length;
820 
821 	if (strcmp((char *)iva, "cows can fly"))
822 		return -1;
823 
824 	ivap = (u32 *)iva;
825 
826 	for (i = 0; i < 8; i++)
827 	    *ivap++ = 0;
828 
829 	/* Compute Checksum for HPMC handler */
830 	length = os_hpmc_size;
831 	ivap[7] = length;
832 
833 	hpmcp = (u32 *)os_hpmc;
834 
835 	for (i=0; i<length/4; i++)
836 	    check += *hpmcp++;
837 
838 	for (i=0; i<8; i++)
839 	    check += ivap[i];
840 
841 	ivap[5] = -check;
842 
843 	return 0;
844 }
845 
846 #ifndef CONFIG_64BIT
847 extern const void fault_vector_11;
848 #endif
849 extern const void fault_vector_20;
850 
851 void __init trap_init(void)
852 {
853 	void *iva;
854 
855 	if (boot_cpu_data.cpu_type >= pcxu)
856 		iva = (void *) &fault_vector_20;
857 	else
858 #ifdef CONFIG_64BIT
859 		panic("Can't boot 64-bit OS on PA1.1 processor!");
860 #else
861 		iva = (void *) &fault_vector_11;
862 #endif
863 
864 	if (check_ivt(iva))
865 		panic("IVT invalid");
866 }
867