xref: /openbmc/linux/arch/parisc/kernel/traps.c (revision 6c33a6f4)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/arch/parisc/traps.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  *  Copyright (C) 1999, 2000  Philipp Rumpf <prumpf@tux.org>
7  */
8 
9 /*
10  * 'Traps.c' handles hardware traps and faults after we have saved some
11  * state in 'asm.s'.
12  */
13 
14 #include <linux/sched.h>
15 #include <linux/sched/debug.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/ptrace.h>
20 #include <linux/timer.h>
21 #include <linux/delay.h>
22 #include <linux/mm.h>
23 #include <linux/module.h>
24 #include <linux/smp.h>
25 #include <linux/spinlock.h>
26 #include <linux/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/console.h>
29 #include <linux/bug.h>
30 #include <linux/ratelimit.h>
31 #include <linux/uaccess.h>
32 #include <linux/kdebug.h>
33 
34 #include <asm/assembly.h>
35 #include <asm/io.h>
36 #include <asm/irq.h>
37 #include <asm/traps.h>
38 #include <asm/unaligned.h>
39 #include <linux/atomic.h>
40 #include <asm/smp.h>
41 #include <asm/pdc.h>
42 #include <asm/pdc_chassis.h>
43 #include <asm/unwind.h>
44 #include <asm/tlbflush.h>
45 #include <asm/cacheflush.h>
46 #include <linux/kgdb.h>
47 #include <linux/kprobes.h>
48 
49 #include "../math-emu/math-emu.h"	/* for handle_fpe() */
50 
51 static void parisc_show_stack(struct task_struct *task,
52 	struct pt_regs *regs);
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, user;
122 	char *level;
123 	unsigned long cr30, cr31;
124 
125 	user = user_mode(regs);
126 	level = user ? KERN_DEBUG : KERN_CRIT;
127 
128 	show_regs_print_info(level);
129 
130 	print_gr(level, regs);
131 
132 	for (i = 0; i < 8; i += 4)
133 		PRINTREGS(level, regs->sr, "sr", RFMT, i);
134 
135 	if (user)
136 		print_fr(level, regs);
137 
138 	cr30 = mfctl(30);
139 	cr31 = mfctl(31);
140 	printk("%s\n", level);
141 	printk("%sIASQ: " RFMT " " RFMT " IAOQ: " RFMT " " RFMT "\n",
142 	       level, regs->iasq[0], regs->iasq[1], regs->iaoq[0], regs->iaoq[1]);
143 	printk("%s IIR: %08lx    ISR: " RFMT "  IOR: " RFMT "\n",
144 	       level, regs->iir, regs->isr, regs->ior);
145 	printk("%s CPU: %8d   CR30: " RFMT " CR31: " RFMT "\n",
146 	       level, current_thread_info()->cpu, cr30, cr31);
147 	printk("%s ORIG_R28: " RFMT "\n", level, regs->orig_r28);
148 
149 	if (user) {
150 		printk("%s IAOQ[0]: " RFMT "\n", level, regs->iaoq[0]);
151 		printk("%s IAOQ[1]: " RFMT "\n", level, regs->iaoq[1]);
152 		printk("%s RP(r2): " RFMT "\n", level, regs->gr[2]);
153 	} else {
154 		printk("%s IAOQ[0]: %pS\n", level, (void *) regs->iaoq[0]);
155 		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
156 		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
157 
158 		parisc_show_stack(current, regs);
159 	}
160 }
161 
162 static DEFINE_RATELIMIT_STATE(_hppa_rs,
163 	DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST);
164 
165 #define parisc_printk_ratelimited(critical, regs, fmt, ...)	{	      \
166 	if ((critical || show_unhandled_signals) && __ratelimit(&_hppa_rs)) { \
167 		printk(fmt, ##__VA_ARGS__);				      \
168 		show_regs(regs);					      \
169 	}								      \
170 }
171 
172 
173 static void do_show_stack(struct unwind_frame_info *info)
174 {
175 	int i = 1;
176 
177 	printk(KERN_CRIT "Backtrace:\n");
178 	while (i <= MAX_UNWIND_ENTRIES) {
179 		if (unwind_once(info) < 0 || info->ip == 0)
180 			break;
181 
182 		if (__kernel_text_address(info->ip)) {
183 			printk(KERN_CRIT " [<" RFMT ">] %pS\n",
184 				info->ip, (void *) info->ip);
185 			i++;
186 		}
187 	}
188 	printk(KERN_CRIT "\n");
189 }
190 
191 static void parisc_show_stack(struct task_struct *task,
192 	struct pt_regs *regs)
193 {
194 	struct unwind_frame_info info;
195 
196 	unwind_frame_init_task(&info, task, regs);
197 
198 	do_show_stack(&info);
199 }
200 
201 void show_stack(struct task_struct *t, unsigned long *sp)
202 {
203 	parisc_show_stack(t, NULL);
204 }
205 
206 int is_valid_bugaddr(unsigned long iaoq)
207 {
208 	return 1;
209 }
210 
211 void die_if_kernel(char *str, struct pt_regs *regs, long err)
212 {
213 	if (user_mode(regs)) {
214 		if (err == 0)
215 			return; /* STFU */
216 
217 		parisc_printk_ratelimited(1, regs,
218 			KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
219 			current->comm, task_pid_nr(current), str, err, regs->iaoq[0]);
220 
221 		return;
222 	}
223 
224 	bust_spinlocks(1);
225 
226 	oops_enter();
227 
228 	/* Amuse the user in a SPARC fashion */
229 	if (err) printk(KERN_CRIT
230 			"      _______________________________ \n"
231 			"     < Your System ate a SPARC! Gah! >\n"
232 			"      ------------------------------- \n"
233 			"             \\   ^__^\n"
234 			"                 (__)\\       )\\/\\\n"
235 			"                  U  ||----w |\n"
236 			"                     ||     ||\n");
237 
238 	/* unlock the pdc lock if necessary */
239 	pdc_emergency_unlock();
240 
241 	/* maybe the kernel hasn't booted very far yet and hasn't been able
242 	 * to initialize the serial or STI console. In that case we should
243 	 * re-enable the pdc console, so that the user will be able to
244 	 * identify the problem. */
245 	if (!console_drivers)
246 		pdc_console_restart();
247 
248 	if (err)
249 		printk(KERN_CRIT "%s (pid %d): %s (code %ld)\n",
250 			current->comm, task_pid_nr(current), str, err);
251 
252 	/* Wot's wrong wif bein' racy? */
253 	if (current->thread.flags & PARISC_KERNEL_DEATH) {
254 		printk(KERN_CRIT "%s() recursion detected.\n", __func__);
255 		local_irq_enable();
256 		while (1);
257 	}
258 	current->thread.flags |= PARISC_KERNEL_DEATH;
259 
260 	show_regs(regs);
261 	dump_stack();
262 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
263 
264 	if (in_interrupt())
265 		panic("Fatal exception in interrupt");
266 
267 	if (panic_on_oops)
268 		panic("Fatal exception");
269 
270 	oops_exit();
271 	do_exit(SIGSEGV);
272 }
273 
274 /* gdb uses break 4,8 */
275 #define GDB_BREAK_INSN 0x10004
276 static void handle_gdb_break(struct pt_regs *regs, int wot)
277 {
278 	force_sig_fault(SIGTRAP, wot,
279 			(void __user *) (regs->iaoq[0] & ~3));
280 }
281 
282 static void handle_break(struct pt_regs *regs)
283 {
284 	unsigned iir = regs->iir;
285 
286 	if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
287 		/* check if a BUG() or WARN() trapped here.  */
288 		enum bug_trap_type tt;
289 		tt = report_bug(regs->iaoq[0] & ~3, regs);
290 		if (tt == BUG_TRAP_TYPE_WARN) {
291 			regs->iaoq[0] += 4;
292 			regs->iaoq[1] += 4;
293 			return; /* return to next instruction when WARN_ON().  */
294 		}
295 		die_if_kernel("Unknown kernel breakpoint", regs,
296 			(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
297 	}
298 
299 #ifdef CONFIG_KPROBES
300 	if (unlikely(iir == PARISC_KPROBES_BREAK_INSN)) {
301 		parisc_kprobe_break_handler(regs);
302 		return;
303 	}
304 
305 #endif
306 
307 #ifdef CONFIG_KGDB
308 	if (unlikely(iir == PARISC_KGDB_COMPILED_BREAK_INSN ||
309 		iir == PARISC_KGDB_BREAK_INSN)) {
310 		kgdb_handle_exception(9, SIGTRAP, 0, regs);
311 		return;
312 	}
313 #endif
314 
315 	if (unlikely(iir != GDB_BREAK_INSN))
316 		parisc_printk_ratelimited(0, regs,
317 			KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
318 			iir & 31, (iir>>13) & ((1<<13)-1),
319 			task_pid_nr(current), current->comm);
320 
321 	/* send standard GDB signal */
322 	handle_gdb_break(regs, TRAP_BRKPT);
323 }
324 
325 static void default_trap(int code, struct pt_regs *regs)
326 {
327 	printk(KERN_ERR "Trap %d on CPU %d\n", code, smp_processor_id());
328 	show_regs(regs);
329 }
330 
331 void (*cpu_lpmc) (int code, struct pt_regs *regs) __read_mostly = default_trap;
332 
333 
334 void transfer_pim_to_trap_frame(struct pt_regs *regs)
335 {
336     register int i;
337     extern unsigned int hpmc_pim_data[];
338     struct pdc_hpmc_pim_11 *pim_narrow;
339     struct pdc_hpmc_pim_20 *pim_wide;
340 
341     if (boot_cpu_data.cpu_type >= pcxu) {
342 
343 	pim_wide = (struct pdc_hpmc_pim_20 *)hpmc_pim_data;
344 
345 	/*
346 	 * Note: The following code will probably generate a
347 	 * bunch of truncation error warnings from the compiler.
348 	 * Could be handled with an ifdef, but perhaps there
349 	 * is a better way.
350 	 */
351 
352 	regs->gr[0] = pim_wide->cr[22];
353 
354 	for (i = 1; i < 32; i++)
355 	    regs->gr[i] = pim_wide->gr[i];
356 
357 	for (i = 0; i < 32; i++)
358 	    regs->fr[i] = pim_wide->fr[i];
359 
360 	for (i = 0; i < 8; i++)
361 	    regs->sr[i] = pim_wide->sr[i];
362 
363 	regs->iasq[0] = pim_wide->cr[17];
364 	regs->iasq[1] = pim_wide->iasq_back;
365 	regs->iaoq[0] = pim_wide->cr[18];
366 	regs->iaoq[1] = pim_wide->iaoq_back;
367 
368 	regs->sar  = pim_wide->cr[11];
369 	regs->iir  = pim_wide->cr[19];
370 	regs->isr  = pim_wide->cr[20];
371 	regs->ior  = pim_wide->cr[21];
372     }
373     else {
374 	pim_narrow = (struct pdc_hpmc_pim_11 *)hpmc_pim_data;
375 
376 	regs->gr[0] = pim_narrow->cr[22];
377 
378 	for (i = 1; i < 32; i++)
379 	    regs->gr[i] = pim_narrow->gr[i];
380 
381 	for (i = 0; i < 32; i++)
382 	    regs->fr[i] = pim_narrow->fr[i];
383 
384 	for (i = 0; i < 8; i++)
385 	    regs->sr[i] = pim_narrow->sr[i];
386 
387 	regs->iasq[0] = pim_narrow->cr[17];
388 	regs->iasq[1] = pim_narrow->iasq_back;
389 	regs->iaoq[0] = pim_narrow->cr[18];
390 	regs->iaoq[1] = pim_narrow->iaoq_back;
391 
392 	regs->sar  = pim_narrow->cr[11];
393 	regs->iir  = pim_narrow->cr[19];
394 	regs->isr  = pim_narrow->cr[20];
395 	regs->ior  = pim_narrow->cr[21];
396     }
397 
398     /*
399      * The following fields only have meaning if we came through
400      * another path. So just zero them here.
401      */
402 
403     regs->ksp = 0;
404     regs->kpc = 0;
405     regs->orig_r28 = 0;
406 }
407 
408 
409 /*
410  * This routine is called as a last resort when everything else
411  * has gone clearly wrong. We get called for faults in kernel space,
412  * and HPMC's.
413  */
414 void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long offset)
415 {
416 	static DEFINE_SPINLOCK(terminate_lock);
417 
418 	(void)notify_die(DIE_OOPS, msg, regs, 0, code, SIGTRAP);
419 	bust_spinlocks(1);
420 
421 	set_eiem(0);
422 	local_irq_disable();
423 	spin_lock(&terminate_lock);
424 
425 	/* unlock the pdc lock if necessary */
426 	pdc_emergency_unlock();
427 
428 	/* restart pdc console if necessary */
429 	if (!console_drivers)
430 		pdc_console_restart();
431 
432 	/* Not all paths will gutter the processor... */
433 	switch(code){
434 
435 	case 1:
436 		transfer_pim_to_trap_frame(regs);
437 		break;
438 
439 	default:
440 		/* Fall through */
441 		break;
442 
443 	}
444 
445 	{
446 		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
447 		struct unwind_frame_info info;
448 		unwind_frame_init(&info, current, regs);
449 		do_show_stack(&info);
450 	}
451 
452 	printk("\n");
453 	pr_crit("%s: Code=%d (%s) at addr " RFMT "\n",
454 		msg, code, trap_name(code), offset);
455 	show_regs(regs);
456 
457 	spin_unlock(&terminate_lock);
458 
459 	/* put soft power button back under hardware control;
460 	 * if the user had pressed it once at any time, the
461 	 * system will shut down immediately right here. */
462 	pdc_soft_power_button(0);
463 
464 	/* Call kernel panic() so reboot timeouts work properly
465 	 * FIXME: This function should be on the list of
466 	 * panic notifiers, and we should call panic
467 	 * directly from the location that we wish.
468 	 * e.g. We should not call panic from
469 	 * parisc_terminate, but rather the oter way around.
470 	 * This hack works, prints the panic message twice,
471 	 * and it enables reboot timers!
472 	 */
473 	panic(msg);
474 }
475 
476 void notrace handle_interruption(int code, struct pt_regs *regs)
477 {
478 	unsigned long fault_address = 0;
479 	unsigned long fault_space = 0;
480 	int si_code;
481 
482 	if (code == 1)
483 	    pdc_console_restart();  /* switch back to pdc if HPMC */
484 	else
485 	    local_irq_enable();
486 
487 	/* Security check:
488 	 * If the priority level is still user, and the
489 	 * faulting space is not equal to the active space
490 	 * then the user is attempting something in a space
491 	 * that does not belong to them. Kill the process.
492 	 *
493 	 * This is normally the situation when the user
494 	 * attempts to jump into the kernel space at the
495 	 * wrong offset, be it at the gateway page or a
496 	 * random location.
497 	 *
498 	 * We cannot normally signal the process because it
499 	 * could *be* on the gateway page, and processes
500 	 * executing on the gateway page can't have signals
501 	 * delivered.
502 	 *
503 	 * We merely readjust the address into the users
504 	 * space, at a destination address of zero, and
505 	 * allow processing to continue.
506 	 */
507 	if (((unsigned long)regs->iaoq[0] & 3) &&
508 	    ((unsigned long)regs->iasq[0] != (unsigned long)regs->sr[7])) {
509 		/* Kill the user process later */
510 		regs->iaoq[0] = 0 | 3;
511 		regs->iaoq[1] = regs->iaoq[0] + 4;
512 		regs->iasq[0] = regs->iasq[1] = regs->sr[7];
513 		regs->gr[0] &= ~PSW_B;
514 		return;
515 	}
516 
517 #if 0
518 	printk(KERN_CRIT "Interruption # %d\n", code);
519 #endif
520 
521 	switch(code) {
522 
523 	case  1:
524 		/* High-priority machine check (HPMC) */
525 
526 		/* set up a new led state on systems shipped with a LED State panel */
527 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_HPMC);
528 
529 		parisc_terminate("High Priority Machine Check (HPMC)",
530 				regs, code, 0);
531 		/* NOT REACHED */
532 
533 	case  2:
534 		/* Power failure interrupt */
535 		printk(KERN_CRIT "Power failure interrupt !\n");
536 		return;
537 
538 	case  3:
539 		/* Recovery counter trap */
540 		regs->gr[0] &= ~PSW_R;
541 
542 #ifdef CONFIG_KPROBES
543 		if (parisc_kprobe_ss_handler(regs))
544 			return;
545 #endif
546 
547 #ifdef CONFIG_KGDB
548 		if (kgdb_single_step) {
549 			kgdb_handle_exception(0, SIGTRAP, 0, regs);
550 			return;
551 		}
552 #endif
553 
554 		if (user_space(regs))
555 			handle_gdb_break(regs, TRAP_TRACE);
556 		/* else this must be the start of a syscall - just let it run */
557 		return;
558 
559 	case  5:
560 		/* Low-priority machine check */
561 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_LPMC);
562 
563 		flush_cache_all();
564 		flush_tlb_all();
565 		cpu_lpmc(5, regs);
566 		return;
567 
568 	case  PARISC_ITLB_TRAP:
569 		/* Instruction TLB miss fault/Instruction page fault */
570 		fault_address = regs->iaoq[0];
571 		fault_space   = regs->iasq[0];
572 		break;
573 
574 	case  8:
575 		/* Illegal instruction trap */
576 		die_if_kernel("Illegal instruction", regs, code);
577 		si_code = ILL_ILLOPC;
578 		goto give_sigill;
579 
580 	case  9:
581 		/* Break instruction trap */
582 		handle_break(regs);
583 		return;
584 
585 	case 10:
586 		/* Privileged operation trap */
587 		die_if_kernel("Privileged operation", regs, code);
588 		si_code = ILL_PRVOPC;
589 		goto give_sigill;
590 
591 	case 11:
592 		/* Privileged register trap */
593 		if ((regs->iir & 0xffdfffe0) == 0x034008a0) {
594 
595 			/* This is a MFCTL cr26/cr27 to gr instruction.
596 			 * PCXS traps on this, so we need to emulate it.
597 			 */
598 
599 			if (regs->iir & 0x00200000)
600 				regs->gr[regs->iir & 0x1f] = mfctl(27);
601 			else
602 				regs->gr[regs->iir & 0x1f] = mfctl(26);
603 
604 			regs->iaoq[0] = regs->iaoq[1];
605 			regs->iaoq[1] += 4;
606 			regs->iasq[0] = regs->iasq[1];
607 			return;
608 		}
609 
610 		die_if_kernel("Privileged register usage", regs, code);
611 		si_code = ILL_PRVREG;
612 	give_sigill:
613 		force_sig_fault(SIGILL, si_code,
614 				(void __user *) regs->iaoq[0]);
615 		return;
616 
617 	case 12:
618 		/* Overflow Trap, let the userland signal handler do the cleanup */
619 		force_sig_fault(SIGFPE, FPE_INTOVF,
620 				(void __user *) regs->iaoq[0]);
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 			/* Let userspace app figure it out from the insn pointed
629 			 * to by si_addr.
630 			 */
631 			force_sig_fault(SIGFPE, FPE_CONDTRAP,
632 					(void __user *) regs->iaoq[0]);
633 			return;
634 		}
635 		/* The kernel doesn't want to handle condition codes */
636 		break;
637 
638 	case 14:
639 		/* Assist Exception Trap, i.e. floating point exception. */
640 		die_if_kernel("Floating point exception", regs, 0); /* quiet */
641 		__inc_irq_stat(irq_fpassist_count);
642 		handle_fpe(regs);
643 		return;
644 
645 	case 15:
646 		/* Data TLB miss fault/Data page fault */
647 		/* Fall through */
648 	case 16:
649 		/* Non-access instruction TLB miss fault */
650 		/* The instruction TLB entry needed for the target address of the FIC
651 		   is absent, and hardware can't find it, so we get to cleanup */
652 		/* Fall through */
653 	case 17:
654 		/* Non-access data TLB miss fault/Non-access data page fault */
655 		/* FIXME:
656 			 Still need to add slow path emulation code here!
657 			 If the insn used a non-shadow register, then the tlb
658 			 handlers could not have their side-effect (e.g. probe
659 			 writing to a target register) emulated since rfir would
660 			 erase the changes to said register. Instead we have to
661 			 setup everything, call this function we are in, and emulate
662 			 by hand. Technically we need to emulate:
663 			 fdc,fdce,pdc,"fic,4f",prober,probeir,probew, probeiw
664 		*/
665 		fault_address = regs->ior;
666 		fault_space = regs->isr;
667 		break;
668 
669 	case 18:
670 		/* PCXS only -- later cpu's split this into types 26,27 & 28 */
671 		/* Check for unaligned access */
672 		if (check_unaligned(regs)) {
673 			handle_unaligned(regs);
674 			return;
675 		}
676 		/* Fall Through */
677 	case 26:
678 		/* PCXL: Data memory access rights trap */
679 		fault_address = regs->ior;
680 		fault_space   = regs->isr;
681 		break;
682 
683 	case 19:
684 		/* Data memory break trap */
685 		regs->gr[0] |= PSW_X; /* So we can single-step over the trap */
686 		/* fall thru */
687 	case 21:
688 		/* Page reference trap */
689 		handle_gdb_break(regs, TRAP_HWBKPT);
690 		return;
691 
692 	case 25:
693 		/* Taken branch trap */
694 		regs->gr[0] &= ~PSW_T;
695 		if (user_space(regs))
696 			handle_gdb_break(regs, TRAP_BRANCH);
697 		/* else this must be the start of a syscall - just let it
698 		 * run.
699 		 */
700 		return;
701 
702 	case  7:
703 		/* Instruction access rights */
704 		/* PCXL: Instruction memory protection trap */
705 
706 		/*
707 		 * This could be caused by either: 1) a process attempting
708 		 * to execute within a vma that does not have execute
709 		 * permission, or 2) an access rights violation caused by a
710 		 * flush only translation set up by ptep_get_and_clear().
711 		 * So we check the vma permissions to differentiate the two.
712 		 * If the vma indicates we have execute permission, then
713 		 * the cause is the latter one. In this case, we need to
714 		 * call do_page_fault() to fix the problem.
715 		 */
716 
717 		if (user_mode(regs)) {
718 			struct vm_area_struct *vma;
719 
720 			down_read(&current->mm->mmap_sem);
721 			vma = find_vma(current->mm,regs->iaoq[0]);
722 			if (vma && (regs->iaoq[0] >= vma->vm_start)
723 				&& (vma->vm_flags & VM_EXEC)) {
724 
725 				fault_address = regs->iaoq[0];
726 				fault_space = regs->iasq[0];
727 
728 				up_read(&current->mm->mmap_sem);
729 				break; /* call do_page_fault() */
730 			}
731 			up_read(&current->mm->mmap_sem);
732 		}
733 		/* Fall Through */
734 	case 27:
735 		/* Data memory protection ID trap */
736 		if (code == 27 && !user_mode(regs) &&
737 			fixup_exception(regs))
738 			return;
739 
740 		die_if_kernel("Protection id trap", regs, code);
741 		force_sig_fault(SIGSEGV, SEGV_MAPERR,
742 				(code == 7)?
743 				((void __user *) regs->iaoq[0]) :
744 				((void __user *) regs->ior));
745 		return;
746 
747 	case 28:
748 		/* Unaligned data reference trap */
749 		handle_unaligned(regs);
750 		return;
751 
752 	default:
753 		if (user_mode(regs)) {
754 			parisc_printk_ratelimited(0, regs, KERN_DEBUG
755 				"handle_interruption() pid=%d command='%s'\n",
756 				task_pid_nr(current), current->comm);
757 			/* SIGBUS, for lack of a better one. */
758 			force_sig_fault(SIGBUS, BUS_OBJERR,
759 					(void __user *)regs->ior);
760 			return;
761 		}
762 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
763 
764 		parisc_terminate("Unexpected interruption", regs, code, 0);
765 		/* NOT REACHED */
766 	}
767 
768 	if (user_mode(regs)) {
769 	    if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
770 		parisc_printk_ratelimited(0, regs, KERN_DEBUG
771 				"User fault %d on space 0x%08lx, pid=%d command='%s'\n",
772 				code, fault_space,
773 				task_pid_nr(current), current->comm);
774 		force_sig_fault(SIGSEGV, SEGV_MAPERR,
775 				(void __user *)regs->ior);
776 		return;
777 	    }
778 	}
779 	else {
780 
781 	    /*
782 	     * The kernel should never fault on its own address space,
783 	     * unless pagefault_disable() was called before.
784 	     */
785 
786 	    if (fault_space == 0 && !faulthandler_disabled())
787 	    {
788 		/* Clean up and return if in exception table. */
789 		if (fixup_exception(regs))
790 			return;
791 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
792 		parisc_terminate("Kernel Fault", regs, code, fault_address);
793 	    }
794 	}
795 
796 	do_page_fault(regs, code, fault_address);
797 }
798 
799 
800 void __init initialize_ivt(const void *iva)
801 {
802 	extern u32 os_hpmc_size;
803 	extern const u32 os_hpmc[];
804 
805 	int i;
806 	u32 check = 0;
807 	u32 *ivap;
808 	u32 *hpmcp;
809 	u32 length, instr;
810 
811 	if (strcmp((const char *)iva, "cows can fly"))
812 		panic("IVT invalid");
813 
814 	ivap = (u32 *)iva;
815 
816 	for (i = 0; i < 8; i++)
817 	    *ivap++ = 0;
818 
819 	/*
820 	 * Use PDC_INSTR firmware function to get instruction that invokes
821 	 * PDCE_CHECK in HPMC handler.  See programming note at page 1-31 of
822 	 * the PA 1.1 Firmware Architecture document.
823 	 */
824 	if (pdc_instr(&instr) == PDC_OK)
825 		ivap[0] = instr;
826 
827 	/*
828 	 * Rules for the checksum of the HPMC handler:
829 	 * 1. The IVA does not point to PDC/PDH space (ie: the OS has installed
830 	 *    its own IVA).
831 	 * 2. The word at IVA + 32 is nonzero.
832 	 * 3. If Length (IVA + 60) is not zero, then Length (IVA + 60) and
833 	 *    Address (IVA + 56) are word-aligned.
834 	 * 4. The checksum of the 8 words starting at IVA + 32 plus the sum of
835 	 *    the Length/4 words starting at Address is zero.
836 	 */
837 
838 	/* Setup IVA and compute checksum for HPMC handler */
839 	ivap[6] = (u32)__pa(os_hpmc);
840 	length = os_hpmc_size;
841 	ivap[7] = length;
842 
843 	hpmcp = (u32 *)os_hpmc;
844 
845 	for (i=0; i<length/4; i++)
846 	    check += *hpmcp++;
847 
848 	for (i=0; i<8; i++)
849 	    check += ivap[i];
850 
851 	ivap[5] = -check;
852 }
853 
854 
855 /* early_trap_init() is called before we set up kernel mappings and
856  * write-protect the kernel */
857 void  __init early_trap_init(void)
858 {
859 	extern const void fault_vector_20;
860 
861 #ifndef CONFIG_64BIT
862 	extern const void fault_vector_11;
863 	initialize_ivt(&fault_vector_11);
864 #endif
865 
866 	initialize_ivt(&fault_vector_20);
867 }
868 
869 void __init trap_init(void)
870 {
871 }
872