xref: /linux/arch/parisc/kernel/traps.c (revision bf74b964775009071cf12f9d59d4dd5e388fbe0b)
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/kallsyms.h>
28 #include <linux/bug.h>
29 
30 #include <asm/assembly.h>
31 #include <asm/system.h>
32 #include <asm/uaccess.h>
33 #include <asm/io.h>
34 #include <asm/irq.h>
35 #include <asm/traps.h>
36 #include <asm/unaligned.h>
37 #include <asm/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 #define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
48 			  /*  dumped to the console via printk)          */
49 
50 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
51 DEFINE_SPINLOCK(pa_dbit_lock);
52 #endif
53 
54 static int printbinary(char *buf, unsigned long x, int nbits)
55 {
56 	unsigned long mask = 1UL << (nbits - 1);
57 	while (mask != 0) {
58 		*buf++ = (mask & x ? '1' : '0');
59 		mask >>= 1;
60 	}
61 	*buf = '\0';
62 
63 	return nbits;
64 }
65 
66 #ifdef CONFIG_64BIT
67 #define RFMT "%016lx"
68 #else
69 #define RFMT "%08lx"
70 #endif
71 #define FFMT "%016llx"	/* fpregs are 64-bit always */
72 
73 #define PRINTREGS(lvl,r,f,fmt,x)	\
74 	printk("%s%s%02d-%02d  " fmt " " fmt " " fmt " " fmt "\n",	\
75 		lvl, f, (x), (x+3), (r)[(x)+0], (r)[(x)+1],		\
76 		(r)[(x)+2], (r)[(x)+3])
77 
78 static void print_gr(char *level, struct pt_regs *regs)
79 {
80 	int i;
81 	char buf[64];
82 
83 	printk("%s\n", level);
84 	printk("%s     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI\n", level);
85 	printbinary(buf, regs->gr[0], 32);
86 	printk("%sPSW: %s %s\n", level, buf, print_tainted());
87 
88 	for (i = 0; i < 32; i += 4)
89 		PRINTREGS(level, regs->gr, "r", RFMT, i);
90 }
91 
92 static void print_fr(char *level, struct pt_regs *regs)
93 {
94 	int i;
95 	char buf[64];
96 	struct { u32 sw[2]; } s;
97 
98 	/* FR are 64bit everywhere. Need to use asm to get the content
99 	 * of fpsr/fper1, and we assume that we won't have a FP Identify
100 	 * in our way, otherwise we're screwed.
101 	 * The fldd is used to restore the T-bit if there was one, as the
102 	 * store clears it anyway.
103 	 * PA2.0 book says "thou shall not use fstw on FPSR/FPERs" - T-Bone */
104 	asm volatile ("fstd %%fr0,0(%1)	\n\t"
105 		      "fldd 0(%1),%%fr0	\n\t"
106 		      : "=m" (s) : "r" (&s) : "r0");
107 
108 	printk("%s\n", level);
109 	printk("%s      VZOUICununcqcqcqcqcqcrmunTDVZOUI\n", level);
110 	printbinary(buf, s.sw[0], 32);
111 	printk("%sFPSR: %s\n", level, buf);
112 	printk("%sFPER1: %08x\n", level, s.sw[1]);
113 
114 	/* here we'll print fr0 again, tho it'll be meaningless */
115 	for (i = 0; i < 32; i += 4)
116 		PRINTREGS(level, regs->fr, "fr", FFMT, i);
117 }
118 
119 void show_regs(struct pt_regs *regs)
120 {
121 	int i;
122 	char *level;
123 	unsigned long cr30, cr31;
124 
125 	level = user_mode(regs) ? KERN_DEBUG : KERN_CRIT;
126 
127 	print_gr(level, regs);
128 
129 	for (i = 0; i < 8; i += 4)
130 		PRINTREGS(level, regs->sr, "sr", RFMT, i);
131 
132 	if (user_mode(regs))
133 		print_fr(level, regs);
134 
135 	cr30 = mfctl(30);
136 	cr31 = mfctl(31);
137 	printk("%s\n", level);
138 	printk("%sIASQ: " RFMT " " RFMT " IAOQ: " RFMT " " RFMT "\n",
139 	       level, regs->iasq[0], regs->iasq[1], regs->iaoq[0], regs->iaoq[1]);
140 	printk("%s IIR: %08lx    ISR: " RFMT "  IOR: " RFMT "\n",
141 	       level, regs->iir, regs->isr, regs->ior);
142 	printk("%s CPU: %8d   CR30: " RFMT " CR31: " RFMT "\n",
143 	       level, current_thread_info()->cpu, cr30, cr31);
144 	printk("%s ORIG_R28: " RFMT "\n", level, regs->orig_r28);
145 	printk(level);
146 	print_symbol(" IAOQ[0]: %s\n", regs->iaoq[0]);
147 	printk(level);
148 	print_symbol(" IAOQ[1]: %s\n", regs->iaoq[1]);
149 	printk(level);
150 	print_symbol(" RP(r2): %s\n", regs->gr[2]);
151 }
152 
153 
154 void dump_stack(void)
155 {
156 	show_stack(NULL, NULL);
157 }
158 
159 EXPORT_SYMBOL(dump_stack);
160 
161 static void do_show_stack(struct unwind_frame_info *info)
162 {
163 	int i = 1;
164 
165 	printk(KERN_CRIT "Backtrace:\n");
166 	while (i <= 16) {
167 		if (unwind_once(info) < 0 || info->ip == 0)
168 			break;
169 
170 		if (__kernel_text_address(info->ip)) {
171 			printk("%s [<" RFMT ">] ", (i&0x3)==1 ? KERN_CRIT : "", info->ip);
172 #ifdef CONFIG_KALLSYMS
173 			print_symbol("%s\n", info->ip);
174 #else
175 			if ((i & 0x03) == 0)
176 				printk("\n");
177 #endif
178 			i++;
179 		}
180 	}
181 	printk("\n");
182 }
183 
184 void show_stack(struct task_struct *task, unsigned long *s)
185 {
186 	struct unwind_frame_info info;
187 
188 	if (!task) {
189 		unsigned long sp;
190 
191 HERE:
192 		asm volatile ("copy %%r30, %0" : "=r"(sp));
193 		{
194 			struct pt_regs r;
195 
196 			memset(&r, 0, sizeof(struct pt_regs));
197 			r.iaoq[0] = (unsigned long)&&HERE;
198 			r.gr[2] = (unsigned long)__builtin_return_address(0);
199 			r.gr[30] = sp;
200 
201 			unwind_frame_init(&info, current, &r);
202 		}
203 	} else {
204 		unwind_frame_init_from_blocked_task(&info, task);
205 	}
206 
207 	do_show_stack(&info);
208 }
209 
210 int is_valid_bugaddr(unsigned long iaoq)
211 {
212 	return 1;
213 }
214 
215 void die_if_kernel(char *str, struct pt_regs *regs, long err)
216 {
217 	if (user_mode(regs)) {
218 		if (err == 0)
219 			return; /* STFU */
220 
221 		printk(KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
222 			current->comm, current->pid, str, err, regs->iaoq[0]);
223 #ifdef PRINT_USER_FAULTS
224 		/* XXX for debugging only */
225 		show_regs(regs);
226 #endif
227 		return;
228 	}
229 
230 	oops_in_progress = 1;
231 
232 	/* Amuse the user in a SPARC fashion */
233 	if (err) printk(
234 KERN_CRIT "      _______________________________ \n"
235 KERN_CRIT "     < Your System ate a SPARC! Gah! >\n"
236 KERN_CRIT "      ------------------------------- \n"
237 KERN_CRIT "             \\   ^__^\n"
238 KERN_CRIT "              \\  (xx)\\_______\n"
239 KERN_CRIT "                 (__)\\       )\\/\\\n"
240 KERN_CRIT "                  U  ||----w |\n"
241 KERN_CRIT "                     ||     ||\n");
242 
243 	/* unlock the pdc lock if necessary */
244 	pdc_emergency_unlock();
245 
246 	/* maybe the kernel hasn't booted very far yet and hasn't been able
247 	 * to initialize the serial or STI console. In that case we should
248 	 * re-enable the pdc console, so that the user will be able to
249 	 * identify the problem. */
250 	if (!console_drivers)
251 		pdc_console_restart();
252 
253 	if (err)
254 		printk(KERN_CRIT "%s (pid %d): %s (code %ld)\n",
255 			current->comm, current->pid, str, err);
256 
257 	/* Wot's wrong wif bein' racy? */
258 	if (current->thread.flags & PARISC_KERNEL_DEATH) {
259 		printk(KERN_CRIT "%s() recursion detected.\n", __FUNCTION__);
260 		local_irq_enable();
261 		while (1);
262 	}
263 	current->thread.flags |= PARISC_KERNEL_DEATH;
264 
265 	show_regs(regs);
266 	dump_stack();
267 
268 	if (in_interrupt())
269 		panic("Fatal exception in interrupt");
270 
271 	if (panic_on_oops) {
272 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
273 		ssleep(5);
274 		panic("Fatal exception");
275 	}
276 
277 	do_exit(SIGSEGV);
278 }
279 
280 int syscall_ipi(int (*syscall) (struct pt_regs *), struct pt_regs *regs)
281 {
282 	return syscall(regs);
283 }
284 
285 /* gdb uses break 4,8 */
286 #define GDB_BREAK_INSN 0x10004
287 static void handle_gdb_break(struct pt_regs *regs, int wot)
288 {
289 	struct siginfo si;
290 
291 	si.si_signo = SIGTRAP;
292 	si.si_errno = 0;
293 	si.si_code = wot;
294 	si.si_addr = (void __user *) (regs->iaoq[0] & ~3);
295 	force_sig_info(SIGTRAP, &si, current);
296 }
297 
298 static void handle_break(struct pt_regs *regs)
299 {
300 	unsigned iir = regs->iir;
301 
302 	if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
303 		/* check if a BUG() or WARN() trapped here.  */
304 		enum bug_trap_type tt;
305 		tt = report_bug(regs->iaoq[0] & ~3);
306 		if (tt == BUG_TRAP_TYPE_WARN) {
307 			regs->iaoq[0] += 4;
308 			regs->iaoq[1] += 4;
309 			return; /* return to next instruction when WARN_ON().  */
310 		}
311 		die_if_kernel("Unknown kernel breakpoint", regs,
312 			(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
313 	}
314 
315 #ifdef PRINT_USER_FAULTS
316 	if (unlikely(iir != GDB_BREAK_INSN)) {
317 		printk(KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
318 			iir & 31, (iir>>13) & ((1<<13)-1),
319 			current->pid, current->comm);
320 		show_regs(regs);
321 	}
322 #endif
323 
324 	/* send standard GDB signal */
325 	handle_gdb_break(regs, TRAP_BRKPT);
326 }
327 
328 static void default_trap(int code, struct pt_regs *regs)
329 {
330 	printk(KERN_ERR "Trap %d on CPU %d\n", code, smp_processor_id());
331 	show_regs(regs);
332 }
333 
334 void (*cpu_lpmc) (int code, struct pt_regs *regs) __read_mostly = default_trap;
335 
336 
337 void transfer_pim_to_trap_frame(struct pt_regs *regs)
338 {
339     register int i;
340     extern unsigned int hpmc_pim_data[];
341     struct pdc_hpmc_pim_11 *pim_narrow;
342     struct pdc_hpmc_pim_20 *pim_wide;
343 
344     if (boot_cpu_data.cpu_type >= pcxu) {
345 
346 	pim_wide = (struct pdc_hpmc_pim_20 *)hpmc_pim_data;
347 
348 	/*
349 	 * Note: The following code will probably generate a
350 	 * bunch of truncation error warnings from the compiler.
351 	 * Could be handled with an ifdef, but perhaps there
352 	 * is a better way.
353 	 */
354 
355 	regs->gr[0] = pim_wide->cr[22];
356 
357 	for (i = 1; i < 32; i++)
358 	    regs->gr[i] = pim_wide->gr[i];
359 
360 	for (i = 0; i < 32; i++)
361 	    regs->fr[i] = pim_wide->fr[i];
362 
363 	for (i = 0; i < 8; i++)
364 	    regs->sr[i] = pim_wide->sr[i];
365 
366 	regs->iasq[0] = pim_wide->cr[17];
367 	regs->iasq[1] = pim_wide->iasq_back;
368 	regs->iaoq[0] = pim_wide->cr[18];
369 	regs->iaoq[1] = pim_wide->iaoq_back;
370 
371 	regs->sar  = pim_wide->cr[11];
372 	regs->iir  = pim_wide->cr[19];
373 	regs->isr  = pim_wide->cr[20];
374 	regs->ior  = pim_wide->cr[21];
375     }
376     else {
377 	pim_narrow = (struct pdc_hpmc_pim_11 *)hpmc_pim_data;
378 
379 	regs->gr[0] = pim_narrow->cr[22];
380 
381 	for (i = 1; i < 32; i++)
382 	    regs->gr[i] = pim_narrow->gr[i];
383 
384 	for (i = 0; i < 32; i++)
385 	    regs->fr[i] = pim_narrow->fr[i];
386 
387 	for (i = 0; i < 8; i++)
388 	    regs->sr[i] = pim_narrow->sr[i];
389 
390 	regs->iasq[0] = pim_narrow->cr[17];
391 	regs->iasq[1] = pim_narrow->iasq_back;
392 	regs->iaoq[0] = pim_narrow->cr[18];
393 	regs->iaoq[1] = pim_narrow->iaoq_back;
394 
395 	regs->sar  = pim_narrow->cr[11];
396 	regs->iir  = pim_narrow->cr[19];
397 	regs->isr  = pim_narrow->cr[20];
398 	regs->ior  = pim_narrow->cr[21];
399     }
400 
401     /*
402      * The following fields only have meaning if we came through
403      * another path. So just zero them here.
404      */
405 
406     regs->ksp = 0;
407     regs->kpc = 0;
408     regs->orig_r28 = 0;
409 }
410 
411 
412 /*
413  * This routine is called as a last resort when everything else
414  * has gone clearly wrong. We get called for faults in kernel space,
415  * and HPMC's.
416  */
417 void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long offset)
418 {
419 	static DEFINE_SPINLOCK(terminate_lock);
420 
421 	oops_in_progress = 1;
422 
423 	set_eiem(0);
424 	local_irq_disable();
425 	spin_lock(&terminate_lock);
426 
427 	/* unlock the pdc lock if necessary */
428 	pdc_emergency_unlock();
429 
430 	/* restart pdc console if necessary */
431 	if (!console_drivers)
432 		pdc_console_restart();
433 
434 	/* Not all paths will gutter the processor... */
435 	switch(code){
436 
437 	case 1:
438 		transfer_pim_to_trap_frame(regs);
439 		break;
440 
441 	default:
442 		/* Fall through */
443 		break;
444 
445 	}
446 
447 	{
448 		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
449 		struct unwind_frame_info info;
450 		unwind_frame_init(&info, current, regs);
451 		do_show_stack(&info);
452 	}
453 
454 	printk("\n");
455 	printk(KERN_CRIT "%s: Code=%d regs=%p (Addr=" RFMT ")\n",
456 			msg, code, regs, offset);
457 	show_regs(regs);
458 
459 	spin_unlock(&terminate_lock);
460 
461 	/* put soft power button back under hardware control;
462 	 * if the user had pressed it once at any time, the
463 	 * system will shut down immediately right here. */
464 	pdc_soft_power_button(0);
465 
466 	/* Call kernel panic() so reboot timeouts work properly
467 	 * FIXME: This function should be on the list of
468 	 * panic notifiers, and we should call panic
469 	 * directly from the location that we wish.
470 	 * e.g. We should not call panic from
471 	 * parisc_terminate, but rather the oter way around.
472 	 * This hack works, prints the panic message twice,
473 	 * and it enables reboot timers!
474 	 */
475 	panic(msg);
476 }
477 
478 void handle_interruption(int code, struct pt_regs *regs)
479 {
480 	unsigned long fault_address = 0;
481 	unsigned long fault_space = 0;
482 	struct siginfo si;
483 
484 	if (code == 1)
485 	    pdc_console_restart();  /* switch back to pdc if HPMC */
486 	else
487 	    local_irq_enable();
488 
489 	/* Security check:
490 	 * If the priority level is still user, and the
491 	 * faulting space is not equal to the active space
492 	 * then the user is attempting something in a space
493 	 * that does not belong to them. Kill the process.
494 	 *
495 	 * This is normally the situation when the user
496 	 * attempts to jump into the kernel space at the
497 	 * wrong offset, be it at the gateway page or a
498 	 * random location.
499 	 *
500 	 * We cannot normally signal the process because it
501 	 * could *be* on the gateway page, and processes
502 	 * executing on the gateway page can't have signals
503 	 * delivered.
504 	 *
505 	 * We merely readjust the address into the users
506 	 * space, at a destination address of zero, and
507 	 * allow processing to continue.
508 	 */
509 	if (((unsigned long)regs->iaoq[0] & 3) &&
510 	    ((unsigned long)regs->iasq[0] != (unsigned long)regs->sr[7])) {
511 	  	/* Kill the user process later */
512 	  	regs->iaoq[0] = 0 | 3;
513 		regs->iaoq[1] = regs->iaoq[0] + 4;
514 	 	regs->iasq[0] = regs->iasq[0] = regs->sr[7];
515 		regs->gr[0] &= ~PSW_B;
516 		return;
517 	}
518 
519 #if 0
520 	printk(KERN_CRIT "Interruption # %d\n", code);
521 #endif
522 
523 	switch(code) {
524 
525 	case  1:
526 		/* High-priority machine check (HPMC) */
527 
528 		/* set up a new led state on systems shipped with a LED State panel */
529 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_HPMC);
530 
531 	    	parisc_terminate("High Priority Machine Check (HPMC)",
532 				regs, code, 0);
533 		/* NOT REACHED */
534 
535 	case  2:
536 		/* Power failure interrupt */
537 		printk(KERN_CRIT "Power failure interrupt !\n");
538 		return;
539 
540 	case  3:
541 		/* Recovery counter trap */
542 		regs->gr[0] &= ~PSW_R;
543 		if (user_space(regs))
544 			handle_gdb_break(regs, TRAP_TRACE);
545 		/* else this must be the start of a syscall - just let it run */
546 		return;
547 
548 	case  5:
549 		/* Low-priority machine check */
550 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_LPMC);
551 
552 		flush_cache_all();
553 		flush_tlb_all();
554 		cpu_lpmc(5, regs);
555 		return;
556 
557 	case  6:
558 		/* Instruction TLB miss fault/Instruction page fault */
559 		fault_address = regs->iaoq[0];
560 		fault_space   = regs->iasq[0];
561 		break;
562 
563 	case  8:
564 		/* Illegal instruction trap */
565 		die_if_kernel("Illegal instruction", regs, code);
566 		si.si_code = ILL_ILLOPC;
567 		goto give_sigill;
568 
569 	case  9:
570 		/* Break instruction trap */
571 		handle_break(regs);
572 		return;
573 
574 	case 10:
575 		/* Privileged operation trap */
576 		die_if_kernel("Privileged operation", regs, code);
577 		si.si_code = ILL_PRVOPC;
578 		goto give_sigill;
579 
580 	case 11:
581 		/* Privileged register trap */
582 		if ((regs->iir & 0xffdfffe0) == 0x034008a0) {
583 
584 			/* This is a MFCTL cr26/cr27 to gr instruction.
585 			 * PCXS traps on this, so we need to emulate it.
586 			 */
587 
588 			if (regs->iir & 0x00200000)
589 				regs->gr[regs->iir & 0x1f] = mfctl(27);
590 			else
591 				regs->gr[regs->iir & 0x1f] = mfctl(26);
592 
593 			regs->iaoq[0] = regs->iaoq[1];
594 			regs->iaoq[1] += 4;
595 			regs->iasq[0] = regs->iasq[1];
596 			return;
597 		}
598 
599 		die_if_kernel("Privileged register usage", regs, code);
600 		si.si_code = ILL_PRVREG;
601 	give_sigill:
602 		si.si_signo = SIGILL;
603 		si.si_errno = 0;
604 		si.si_addr = (void __user *) regs->iaoq[0];
605 		force_sig_info(SIGILL, &si, current);
606 		return;
607 
608 	case 12:
609 		/* Overflow Trap, let the userland signal handler do the cleanup */
610 		si.si_signo = SIGFPE;
611 		si.si_code = FPE_INTOVF;
612 		si.si_addr = (void __user *) regs->iaoq[0];
613 		force_sig_info(SIGFPE, &si, current);
614 		return;
615 
616 	case 13:
617 		/* Conditional Trap
618 		   The condition succeeds in an instruction which traps
619 		   on condition  */
620 		if(user_mode(regs)){
621 			si.si_signo = SIGFPE;
622 			/* Set to zero, and let the userspace app figure it out from
623 		   	   the insn pointed to by si_addr */
624 			si.si_code = 0;
625 			si.si_addr = (void __user *) regs->iaoq[0];
626 			force_sig_info(SIGFPE, &si, current);
627 			return;
628 		}
629 		/* The kernel doesn't want to handle condition codes */
630 		break;
631 
632 	case 14:
633 		/* Assist Exception Trap, i.e. floating point exception. */
634 		die_if_kernel("Floating point exception", regs, 0); /* quiet */
635 		handle_fpe(regs);
636 		return;
637 
638 	case 15:
639 		/* Data TLB miss fault/Data page fault */
640 		/* Fall through */
641 	case 16:
642 		/* Non-access instruction TLB miss fault */
643 		/* The instruction TLB entry needed for the target address of the FIC
644 		   is absent, and hardware can't find it, so we get to cleanup */
645 		/* Fall through */
646 	case 17:
647 		/* Non-access data TLB miss fault/Non-access data page fault */
648 		/* FIXME:
649 		 	 Still need to add slow path emulation code here!
650 		         If the insn used a non-shadow register, then the tlb
651 			 handlers could not have their side-effect (e.g. probe
652 			 writing to a target register) emulated since rfir would
653 			 erase the changes to said register. Instead we have to
654 			 setup everything, call this function we are in, and emulate
655 			 by hand. Technically we need to emulate:
656 			 fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw
657 		*/
658 		fault_address = regs->ior;
659 		fault_space = regs->isr;
660 		break;
661 
662 	case 18:
663 		/* PCXS only -- later cpu's split this into types 26,27 & 28 */
664 		/* Check for unaligned access */
665 		if (check_unaligned(regs)) {
666 			handle_unaligned(regs);
667 			return;
668 		}
669 		/* Fall Through */
670 	case 26:
671 		/* PCXL: Data memory access rights trap */
672 		fault_address = regs->ior;
673 		fault_space   = regs->isr;
674 		break;
675 
676 	case 19:
677 		/* Data memory break trap */
678 		regs->gr[0] |= PSW_X; /* So we can single-step over the trap */
679 		/* fall thru */
680 	case 21:
681 		/* Page reference trap */
682 		handle_gdb_break(regs, TRAP_HWBKPT);
683 		return;
684 
685 	case 25:
686 		/* Taken branch trap */
687 		regs->gr[0] &= ~PSW_T;
688 		if (user_space(regs))
689 			handle_gdb_break(regs, TRAP_BRANCH);
690 		/* else this must be the start of a syscall - just let it
691 		 * run.
692 		 */
693 		return;
694 
695 	case  7:
696 		/* Instruction access rights */
697 		/* PCXL: Instruction memory protection trap */
698 
699 		/*
700 		 * This could be caused by either: 1) a process attempting
701 		 * to execute within a vma that does not have execute
702 		 * permission, or 2) an access rights violation caused by a
703 		 * flush only translation set up by ptep_get_and_clear().
704 		 * So we check the vma permissions to differentiate the two.
705 		 * If the vma indicates we have execute permission, then
706 		 * the cause is the latter one. In this case, we need to
707 		 * call do_page_fault() to fix the problem.
708 		 */
709 
710 		if (user_mode(regs)) {
711 			struct vm_area_struct *vma;
712 
713 			down_read(&current->mm->mmap_sem);
714 			vma = find_vma(current->mm,regs->iaoq[0]);
715 			if (vma && (regs->iaoq[0] >= vma->vm_start)
716 				&& (vma->vm_flags & VM_EXEC)) {
717 
718 				fault_address = regs->iaoq[0];
719 				fault_space = regs->iasq[0];
720 
721 				up_read(&current->mm->mmap_sem);
722 				break; /* call do_page_fault() */
723 			}
724 			up_read(&current->mm->mmap_sem);
725 		}
726 		/* Fall Through */
727 	case 27:
728 		/* Data memory protection ID trap */
729 		die_if_kernel("Protection id trap", regs, code);
730 		si.si_code = SEGV_MAPERR;
731 		si.si_signo = SIGSEGV;
732 		si.si_errno = 0;
733 		if (code == 7)
734 		    si.si_addr = (void __user *) regs->iaoq[0];
735 		else
736 		    si.si_addr = (void __user *) regs->ior;
737 		force_sig_info(SIGSEGV, &si, current);
738 		return;
739 
740 	case 28:
741 		/* Unaligned data reference trap */
742 		handle_unaligned(regs);
743 		return;
744 
745 	default:
746 		if (user_mode(regs)) {
747 #ifdef PRINT_USER_FAULTS
748 			printk(KERN_DEBUG "\nhandle_interruption() pid=%d command='%s'\n",
749 			    current->pid, current->comm);
750 			show_regs(regs);
751 #endif
752 			/* SIGBUS, for lack of a better one. */
753 			si.si_signo = SIGBUS;
754 			si.si_code = BUS_OBJERR;
755 			si.si_errno = 0;
756 			si.si_addr = (void __user *) regs->ior;
757 			force_sig_info(SIGBUS, &si, current);
758 			return;
759 		}
760 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
761 
762 		parisc_terminate("Unexpected interruption", regs, code, 0);
763 		/* NOT REACHED */
764 	}
765 
766 	if (user_mode(regs)) {
767 	    if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
768 #ifdef PRINT_USER_FAULTS
769 		if (fault_space == 0)
770 			printk(KERN_DEBUG "User Fault on Kernel Space ");
771 		else
772 			printk(KERN_DEBUG "User Fault (long pointer) (fault %d) ",
773 			       code);
774 		printk("pid=%d command='%s'\n", current->pid, current->comm);
775 		show_regs(regs);
776 #endif
777 		si.si_signo = SIGSEGV;
778 		si.si_errno = 0;
779 		si.si_code = SEGV_MAPERR;
780 		si.si_addr = (void __user *) regs->ior;
781 		force_sig_info(SIGSEGV, &si, current);
782 		return;
783 	    }
784 	}
785 	else {
786 
787 	    /*
788 	     * The kernel should never fault on its own address space.
789 	     */
790 
791 	    if (fault_space == 0)
792 	    {
793 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
794 		parisc_terminate("Kernel Fault", regs, code, fault_address);
795 
796 	    }
797 	}
798 
799 	do_page_fault(regs, code, fault_address);
800 }
801 
802 
803 int __init check_ivt(void *iva)
804 {
805 	extern const u32 os_hpmc[];
806 	extern const u32 os_hpmc_end[];
807 
808 	int i;
809 	u32 check = 0;
810 	u32 *ivap;
811 	u32 *hpmcp;
812 	u32 length;
813 
814 	if (strcmp((char *)iva, "cows can fly"))
815 		return -1;
816 
817 	ivap = (u32 *)iva;
818 
819 	for (i = 0; i < 8; i++)
820 	    *ivap++ = 0;
821 
822 	/* Compute Checksum for HPMC handler */
823 
824 	length = os_hpmc_end - os_hpmc;
825 	ivap[7] = length;
826 
827 	hpmcp = (u32 *)os_hpmc;
828 
829 	for (i=0; i<length/4; i++)
830 	    check += *hpmcp++;
831 
832 	for (i=0; i<8; i++)
833 	    check += ivap[i];
834 
835 	ivap[5] = -check;
836 
837 	return 0;
838 }
839 
840 #ifndef CONFIG_64BIT
841 extern const void fault_vector_11;
842 #endif
843 extern const void fault_vector_20;
844 
845 void __init trap_init(void)
846 {
847 	void *iva;
848 
849 	if (boot_cpu_data.cpu_type >= pcxu)
850 		iva = (void *) &fault_vector_20;
851 	else
852 #ifdef CONFIG_64BIT
853 		panic("Can't boot 64-bit OS on PA1.1 processor!");
854 #else
855 		iva = (void *) &fault_vector_11;
856 #endif
857 
858 	if (check_ivt(iva))
859 		panic("IVT invalid");
860 }
861