xref: /openbmc/linux/arch/parisc/kernel/traps.c (revision f7018c21)
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 
29 #include <asm/assembly.h>
30 #include <asm/uaccess.h>
31 #include <asm/io.h>
32 #include <asm/irq.h>
33 #include <asm/traps.h>
34 #include <asm/unaligned.h>
35 #include <linux/atomic.h>
36 #include <asm/smp.h>
37 #include <asm/pdc.h>
38 #include <asm/pdc_chassis.h>
39 #include <asm/unwind.h>
40 #include <asm/tlbflush.h>
41 #include <asm/cacheflush.h>
42 
43 #include "../math-emu/math-emu.h"	/* for handle_fpe() */
44 
45 #define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
46 			  /*  dumped to the console via printk)          */
47 
48 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
49 DEFINE_SPINLOCK(pa_dbit_lock);
50 #endif
51 
52 static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
53 	struct pt_regs *regs);
54 
55 static int printbinary(char *buf, unsigned long x, int nbits)
56 {
57 	unsigned long mask = 1UL << (nbits - 1);
58 	while (mask != 0) {
59 		*buf++ = (mask & x ? '1' : '0');
60 		mask >>= 1;
61 	}
62 	*buf = '\0';
63 
64 	return nbits;
65 }
66 
67 #ifdef CONFIG_64BIT
68 #define RFMT "%016lx"
69 #else
70 #define RFMT "%08lx"
71 #endif
72 #define FFMT "%016llx"	/* fpregs are 64-bit always */
73 
74 #define PRINTREGS(lvl,r,f,fmt,x)	\
75 	printk("%s%s%02d-%02d  " fmt " " fmt " " fmt " " fmt "\n",	\
76 		lvl, f, (x), (x+3), (r)[(x)+0], (r)[(x)+1],		\
77 		(r)[(x)+2], (r)[(x)+3])
78 
79 static void print_gr(char *level, struct pt_regs *regs)
80 {
81 	int i;
82 	char buf[64];
83 
84 	printk("%s\n", level);
85 	printk("%s     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI\n", level);
86 	printbinary(buf, regs->gr[0], 32);
87 	printk("%sPSW: %s %s\n", level, buf, print_tainted());
88 
89 	for (i = 0; i < 32; i += 4)
90 		PRINTREGS(level, regs->gr, "r", RFMT, i);
91 }
92 
93 static void print_fr(char *level, struct pt_regs *regs)
94 {
95 	int i;
96 	char buf[64];
97 	struct { u32 sw[2]; } s;
98 
99 	/* FR are 64bit everywhere. Need to use asm to get the content
100 	 * of fpsr/fper1, and we assume that we won't have a FP Identify
101 	 * in our way, otherwise we're screwed.
102 	 * The fldd is used to restore the T-bit if there was one, as the
103 	 * store clears it anyway.
104 	 * PA2.0 book says "thou shall not use fstw on FPSR/FPERs" - T-Bone */
105 	asm volatile ("fstd %%fr0,0(%1)	\n\t"
106 		      "fldd 0(%1),%%fr0	\n\t"
107 		      : "=m" (s) : "r" (&s) : "r0");
108 
109 	printk("%s\n", level);
110 	printk("%s      VZOUICununcqcqcqcqcqcrmunTDVZOUI\n", level);
111 	printbinary(buf, s.sw[0], 32);
112 	printk("%sFPSR: %s\n", level, buf);
113 	printk("%sFPER1: %08x\n", level, s.sw[1]);
114 
115 	/* here we'll print fr0 again, tho it'll be meaningless */
116 	for (i = 0; i < 32; i += 4)
117 		PRINTREGS(level, regs->fr, "fr", FFMT, i);
118 }
119 
120 void show_regs(struct pt_regs *regs)
121 {
122 	int i, user;
123 	char *level;
124 	unsigned long cr30, cr31;
125 
126 	user = user_mode(regs);
127 	level = user ? KERN_DEBUG : KERN_CRIT;
128 
129 	show_regs_print_info(level);
130 
131 	print_gr(level, regs);
132 
133 	for (i = 0; i < 8; i += 4)
134 		PRINTREGS(level, regs->sr, "sr", RFMT, i);
135 
136 	if (user)
137 		print_fr(level, regs);
138 
139 	cr30 = mfctl(30);
140 	cr31 = mfctl(31);
141 	printk("%s\n", level);
142 	printk("%sIASQ: " RFMT " " RFMT " IAOQ: " RFMT " " RFMT "\n",
143 	       level, regs->iasq[0], regs->iasq[1], regs->iaoq[0], regs->iaoq[1]);
144 	printk("%s IIR: %08lx    ISR: " RFMT "  IOR: " RFMT "\n",
145 	       level, regs->iir, regs->isr, regs->ior);
146 	printk("%s CPU: %8d   CR30: " RFMT " CR31: " RFMT "\n",
147 	       level, current_thread_info()->cpu, cr30, cr31);
148 	printk("%s ORIG_R28: " RFMT "\n", level, regs->orig_r28);
149 
150 	if (user) {
151 		printk("%s IAOQ[0]: " RFMT "\n", level, regs->iaoq[0]);
152 		printk("%s IAOQ[1]: " RFMT "\n", level, regs->iaoq[1]);
153 		printk("%s RP(r2): " RFMT "\n", level, regs->gr[2]);
154 	} else {
155 		printk("%s IAOQ[0]: %pS\n", level, (void *) regs->iaoq[0]);
156 		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
157 		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
158 
159 		parisc_show_stack(current, NULL, regs);
160 	}
161 }
162 
163 static void do_show_stack(struct unwind_frame_info *info)
164 {
165 	int i = 1;
166 
167 	printk(KERN_CRIT "Backtrace:\n");
168 	while (i <= 16) {
169 		if (unwind_once(info) < 0 || info->ip == 0)
170 			break;
171 
172 		if (__kernel_text_address(info->ip)) {
173 			printk(KERN_CRIT " [<" RFMT ">] %pS\n",
174 				info->ip, (void *) info->ip);
175 			i++;
176 		}
177 	}
178 	printk(KERN_CRIT "\n");
179 }
180 
181 static void parisc_show_stack(struct task_struct *task, unsigned long *sp,
182 	struct pt_regs *regs)
183 {
184 	struct unwind_frame_info info;
185 	struct task_struct *t;
186 
187 	t = task ? task : current;
188 	if (regs) {
189 		unwind_frame_init(&info, t, regs);
190 		goto show_stack;
191 	}
192 
193 	if (t == current) {
194 		unsigned long sp;
195 
196 HERE:
197 		asm volatile ("copy %%r30, %0" : "=r"(sp));
198 		{
199 			struct pt_regs r;
200 
201 			memset(&r, 0, sizeof(struct pt_regs));
202 			r.iaoq[0] = (unsigned long)&&HERE;
203 			r.gr[2] = (unsigned long)__builtin_return_address(0);
204 			r.gr[30] = sp;
205 
206 			unwind_frame_init(&info, current, &r);
207 		}
208 	} else {
209 		unwind_frame_init_from_blocked_task(&info, t);
210 	}
211 
212 show_stack:
213 	do_show_stack(&info);
214 }
215 
216 void show_stack(struct task_struct *t, unsigned long *sp)
217 {
218 	return parisc_show_stack(t, sp, NULL);
219 }
220 
221 int is_valid_bugaddr(unsigned long iaoq)
222 {
223 	return 1;
224 }
225 
226 void die_if_kernel(char *str, struct pt_regs *regs, long err)
227 {
228 	if (user_mode(regs)) {
229 		if (err == 0)
230 			return; /* STFU */
231 
232 		printk(KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
233 			current->comm, task_pid_nr(current), str, err, regs->iaoq[0]);
234 #ifdef PRINT_USER_FAULTS
235 		/* XXX for debugging only */
236 		show_regs(regs);
237 #endif
238 		return;
239 	}
240 
241 	oops_in_progress = 1;
242 
243 	oops_enter();
244 
245 	/* Amuse the user in a SPARC fashion */
246 	if (err) printk(KERN_CRIT
247 			"      _______________________________ \n"
248 			"     < Your System ate a SPARC! Gah! >\n"
249 			"      ------------------------------- \n"
250 			"             \\   ^__^\n"
251 			"                 (__)\\       )\\/\\\n"
252 			"                  U  ||----w |\n"
253 			"                     ||     ||\n");
254 
255 	/* unlock the pdc lock if necessary */
256 	pdc_emergency_unlock();
257 
258 	/* maybe the kernel hasn't booted very far yet and hasn't been able
259 	 * to initialize the serial or STI console. In that case we should
260 	 * re-enable the pdc console, so that the user will be able to
261 	 * identify the problem. */
262 	if (!console_drivers)
263 		pdc_console_restart();
264 
265 	if (err)
266 		printk(KERN_CRIT "%s (pid %d): %s (code %ld)\n",
267 			current->comm, task_pid_nr(current), str, err);
268 
269 	/* Wot's wrong wif bein' racy? */
270 	if (current->thread.flags & PARISC_KERNEL_DEATH) {
271 		printk(KERN_CRIT "%s() recursion detected.\n", __func__);
272 		local_irq_enable();
273 		while (1);
274 	}
275 	current->thread.flags |= PARISC_KERNEL_DEATH;
276 
277 	show_regs(regs);
278 	dump_stack();
279 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
280 
281 	if (in_interrupt())
282 		panic("Fatal exception in interrupt");
283 
284 	if (panic_on_oops) {
285 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
286 		ssleep(5);
287 		panic("Fatal exception");
288 	}
289 
290 	oops_exit();
291 	do_exit(SIGSEGV);
292 }
293 
294 /* gdb uses break 4,8 */
295 #define GDB_BREAK_INSN 0x10004
296 static void handle_gdb_break(struct pt_regs *regs, int wot)
297 {
298 	struct siginfo si;
299 
300 	si.si_signo = SIGTRAP;
301 	si.si_errno = 0;
302 	si.si_code = wot;
303 	si.si_addr = (void __user *) (regs->iaoq[0] & ~3);
304 	force_sig_info(SIGTRAP, &si, current);
305 }
306 
307 static void handle_break(struct pt_regs *regs)
308 {
309 	unsigned iir = regs->iir;
310 
311 	if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
312 		/* check if a BUG() or WARN() trapped here.  */
313 		enum bug_trap_type tt;
314 		tt = report_bug(regs->iaoq[0] & ~3, regs);
315 		if (tt == BUG_TRAP_TYPE_WARN) {
316 			regs->iaoq[0] += 4;
317 			regs->iaoq[1] += 4;
318 			return; /* return to next instruction when WARN_ON().  */
319 		}
320 		die_if_kernel("Unknown kernel breakpoint", regs,
321 			(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
322 	}
323 
324 #ifdef PRINT_USER_FAULTS
325 	if (unlikely(iir != GDB_BREAK_INSN)) {
326 		printk(KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
327 			iir & 31, (iir>>13) & ((1<<13)-1),
328 			task_pid_nr(current), current->comm);
329 		show_regs(regs);
330 	}
331 #endif
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 #ifdef PRINT_USER_FAULTS
762 			printk(KERN_DEBUG "\nhandle_interruption() pid=%d command='%s'\n",
763 			    task_pid_nr(current), current->comm);
764 			show_regs(regs);
765 #endif
766 			/* SIGBUS, for lack of a better one. */
767 			si.si_signo = SIGBUS;
768 			si.si_code = BUS_OBJERR;
769 			si.si_errno = 0;
770 			si.si_addr = (void __user *) regs->ior;
771 			force_sig_info(SIGBUS, &si, current);
772 			return;
773 		}
774 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
775 
776 		parisc_terminate("Unexpected interruption", regs, code, 0);
777 		/* NOT REACHED */
778 	}
779 
780 	if (user_mode(regs)) {
781 	    if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
782 #ifdef PRINT_USER_FAULTS
783 		if (fault_space == 0)
784 			printk(KERN_DEBUG "User Fault on Kernel Space ");
785 		else
786 			printk(KERN_DEBUG "User Fault (long pointer) (fault %d) ",
787 			       code);
788 		printk(KERN_CONT "pid=%d command='%s'\n",
789 		       task_pid_nr(current), current->comm);
790 		show_regs(regs);
791 #endif
792 		si.si_signo = SIGSEGV;
793 		si.si_errno = 0;
794 		si.si_code = SEGV_MAPERR;
795 		si.si_addr = (void __user *) regs->ior;
796 		force_sig_info(SIGSEGV, &si, current);
797 		return;
798 	    }
799 	}
800 	else {
801 
802 	    /*
803 	     * The kernel should never fault on its own address space,
804 	     * unless pagefault_disable() was called before.
805 	     */
806 
807 	    if (fault_space == 0 && !in_atomic())
808 	    {
809 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
810 		parisc_terminate("Kernel Fault", regs, code, fault_address);
811 	    }
812 	}
813 
814 	do_page_fault(regs, code, fault_address);
815 }
816 
817 
818 int __init check_ivt(void *iva)
819 {
820 	extern u32 os_hpmc_size;
821 	extern const u32 os_hpmc[];
822 
823 	int i;
824 	u32 check = 0;
825 	u32 *ivap;
826 	u32 *hpmcp;
827 	u32 length;
828 
829 	if (strcmp((char *)iva, "cows can fly"))
830 		return -1;
831 
832 	ivap = (u32 *)iva;
833 
834 	for (i = 0; i < 8; i++)
835 	    *ivap++ = 0;
836 
837 	/* Compute Checksum for HPMC handler */
838 	length = os_hpmc_size;
839 	ivap[7] = length;
840 
841 	hpmcp = (u32 *)os_hpmc;
842 
843 	for (i=0; i<length/4; i++)
844 	    check += *hpmcp++;
845 
846 	for (i=0; i<8; i++)
847 	    check += ivap[i];
848 
849 	ivap[5] = -check;
850 
851 	return 0;
852 }
853 
854 #ifndef CONFIG_64BIT
855 extern const void fault_vector_11;
856 #endif
857 extern const void fault_vector_20;
858 
859 void __init trap_init(void)
860 {
861 	void *iva;
862 
863 	if (boot_cpu_data.cpu_type >= pcxu)
864 		iva = (void *) &fault_vector_20;
865 	else
866 #ifdef CONFIG_64BIT
867 		panic("Can't boot 64-bit OS on PA1.1 processor!");
868 #else
869 		iva = (void *) &fault_vector_11;
870 #endif
871 
872 	if (check_ivt(iva))
873 		panic("IVT invalid");
874 }
875