xref: /openbmc/linux/arch/powerpc/kernel/traps.c (revision 1f2d9c9dd8276b1c19ef80e6d8059fe47506d4c3)
1 /*
2  *  Copyright (C) 1995-1996  Gary Thomas (gdt@linuxppc.org)
3  *  Copyright 2007-2010 Freescale Semiconductor, Inc.
4  *
5  *  This program is free software; you can redistribute it and/or
6  *  modify it under the terms of the GNU General Public License
7  *  as published by the Free Software Foundation; either version
8  *  2 of the License, or (at your option) any later version.
9  *
10  *  Modified by Cort Dougan (cort@cs.nmt.edu)
11  *  and Paul Mackerras (paulus@samba.org)
12  */
13 
14 /*
15  * This file handles the architecture-dependent parts of hardware exceptions
16  */
17 
18 #include <linux/errno.h>
19 #include <linux/sched.h>
20 #include <linux/kernel.h>
21 #include <linux/mm.h>
22 #include <linux/stddef.h>
23 #include <linux/unistd.h>
24 #include <linux/ptrace.h>
25 #include <linux/user.h>
26 #include <linux/interrupt.h>
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/prctl.h>
30 #include <linux/delay.h>
31 #include <linux/kprobes.h>
32 #include <linux/kexec.h>
33 #include <linux/backlight.h>
34 #include <linux/bug.h>
35 #include <linux/kdebug.h>
36 #include <linux/debugfs.h>
37 
38 #include <asm/emulated_ops.h>
39 #include <asm/pgtable.h>
40 #include <asm/uaccess.h>
41 #include <asm/system.h>
42 #include <asm/io.h>
43 #include <asm/machdep.h>
44 #include <asm/rtas.h>
45 #include <asm/pmc.h>
46 #ifdef CONFIG_PPC32
47 #include <asm/reg.h>
48 #endif
49 #ifdef CONFIG_PMAC_BACKLIGHT
50 #include <asm/backlight.h>
51 #endif
52 #ifdef CONFIG_PPC64
53 #include <asm/firmware.h>
54 #include <asm/processor.h>
55 #endif
56 #include <asm/kexec.h>
57 #include <asm/ppc-opcode.h>
58 #include <asm/rio.h>
59 
60 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
61 int (*__debugger)(struct pt_regs *regs) __read_mostly;
62 int (*__debugger_ipi)(struct pt_regs *regs) __read_mostly;
63 int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
64 int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
65 int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
66 int (*__debugger_dabr_match)(struct pt_regs *regs) __read_mostly;
67 int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;
68 
69 EXPORT_SYMBOL(__debugger);
70 EXPORT_SYMBOL(__debugger_ipi);
71 EXPORT_SYMBOL(__debugger_bpt);
72 EXPORT_SYMBOL(__debugger_sstep);
73 EXPORT_SYMBOL(__debugger_iabr_match);
74 EXPORT_SYMBOL(__debugger_dabr_match);
75 EXPORT_SYMBOL(__debugger_fault_handler);
76 #endif
77 
78 /*
79  * Trap & Exception support
80  */
81 
82 #ifdef CONFIG_PMAC_BACKLIGHT
83 static void pmac_backlight_unblank(void)
84 {
85 	mutex_lock(&pmac_backlight_mutex);
86 	if (pmac_backlight) {
87 		struct backlight_properties *props;
88 
89 		props = &pmac_backlight->props;
90 		props->brightness = props->max_brightness;
91 		props->power = FB_BLANK_UNBLANK;
92 		backlight_update_status(pmac_backlight);
93 	}
94 	mutex_unlock(&pmac_backlight_mutex);
95 }
96 #else
97 static inline void pmac_backlight_unblank(void) { }
98 #endif
99 
100 int die(const char *str, struct pt_regs *regs, long err)
101 {
102 	static struct {
103 		raw_spinlock_t lock;
104 		u32 lock_owner;
105 		int lock_owner_depth;
106 	} die = {
107 		.lock =			__RAW_SPIN_LOCK_UNLOCKED(die.lock),
108 		.lock_owner =		-1,
109 		.lock_owner_depth =	0
110 	};
111 	static int die_counter;
112 	unsigned long flags;
113 
114 	if (debugger(regs))
115 		return 1;
116 
117 	oops_enter();
118 
119 	if (die.lock_owner != raw_smp_processor_id()) {
120 		console_verbose();
121 		raw_spin_lock_irqsave(&die.lock, flags);
122 		die.lock_owner = smp_processor_id();
123 		die.lock_owner_depth = 0;
124 		bust_spinlocks(1);
125 		if (machine_is(powermac))
126 			pmac_backlight_unblank();
127 	} else {
128 		local_save_flags(flags);
129 	}
130 
131 	if (++die.lock_owner_depth < 3) {
132 		printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
133 #ifdef CONFIG_PREEMPT
134 		printk("PREEMPT ");
135 #endif
136 #ifdef CONFIG_SMP
137 		printk("SMP NR_CPUS=%d ", NR_CPUS);
138 #endif
139 #ifdef CONFIG_DEBUG_PAGEALLOC
140 		printk("DEBUG_PAGEALLOC ");
141 #endif
142 #ifdef CONFIG_NUMA
143 		printk("NUMA ");
144 #endif
145 		printk("%s\n", ppc_md.name ? ppc_md.name : "");
146 
147 		if (notify_die(DIE_OOPS, str, regs, err, 255,
148 			       SIGSEGV) == NOTIFY_STOP)
149 			return 1;
150 
151 		print_modules();
152 		show_regs(regs);
153 	} else {
154 		printk("Recursive die() failure, output suppressed\n");
155 	}
156 
157 	bust_spinlocks(0);
158 	die.lock_owner = -1;
159 	add_taint(TAINT_DIE);
160 	raw_spin_unlock_irqrestore(&die.lock, flags);
161 
162 	if (kexec_should_crash(current) ||
163 		kexec_sr_activated(smp_processor_id()))
164 		crash_kexec(regs);
165 	crash_kexec_secondary(regs);
166 
167 	if (in_interrupt())
168 		panic("Fatal exception in interrupt");
169 
170 	if (panic_on_oops)
171 		panic("Fatal exception");
172 
173 	oops_exit();
174 	do_exit(err);
175 
176 	return 0;
177 }
178 
179 void user_single_step_siginfo(struct task_struct *tsk,
180 				struct pt_regs *regs, siginfo_t *info)
181 {
182 	memset(info, 0, sizeof(*info));
183 	info->si_signo = SIGTRAP;
184 	info->si_code = TRAP_TRACE;
185 	info->si_addr = (void __user *)regs->nip;
186 }
187 
188 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
189 {
190 	siginfo_t info;
191 	const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
192 			"at %08lx nip %08lx lr %08lx code %x\n";
193 	const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
194 			"at %016lx nip %016lx lr %016lx code %x\n";
195 
196 	if (!user_mode(regs)) {
197 		if (die("Exception in kernel mode", regs, signr))
198 			return;
199 	} else if (show_unhandled_signals &&
200 		    unhandled_signal(current, signr) &&
201 		    printk_ratelimit()) {
202 			printk(regs->msr & MSR_64BIT ? fmt64 : fmt32,
203 				current->comm, current->pid, signr,
204 				addr, regs->nip, regs->link, code);
205 		}
206 
207 	memset(&info, 0, sizeof(info));
208 	info.si_signo = signr;
209 	info.si_code = code;
210 	info.si_addr = (void __user *) addr;
211 	force_sig_info(signr, &info, current);
212 }
213 
214 #ifdef CONFIG_PPC64
215 void system_reset_exception(struct pt_regs *regs)
216 {
217 	/* See if any machine dependent calls */
218 	if (ppc_md.system_reset_exception) {
219 		if (ppc_md.system_reset_exception(regs))
220 			return;
221 	}
222 
223 #ifdef CONFIG_KEXEC
224 	cpumask_set_cpu(smp_processor_id(), &cpus_in_sr);
225 #endif
226 
227 	die("System Reset", regs, SIGABRT);
228 
229 	/*
230 	 * Some CPUs when released from the debugger will execute this path.
231 	 * These CPUs entered the debugger via a soft-reset. If the CPU was
232 	 * hung before entering the debugger it will return to the hung
233 	 * state when exiting this function.  This causes a problem in
234 	 * kdump since the hung CPU(s) will not respond to the IPI sent
235 	 * from kdump. To prevent the problem we call crash_kexec_secondary()
236 	 * here. If a kdump had not been initiated or we exit the debugger
237 	 * with the "exit and recover" command (x) crash_kexec_secondary()
238 	 * will return after 5ms and the CPU returns to its previous state.
239 	 */
240 	crash_kexec_secondary(regs);
241 
242 	/* Must die if the interrupt is not recoverable */
243 	if (!(regs->msr & MSR_RI))
244 		panic("Unrecoverable System Reset");
245 
246 	/* What should we do here? We could issue a shutdown or hard reset. */
247 }
248 #endif
249 
250 /*
251  * I/O accesses can cause machine checks on powermacs.
252  * Check if the NIP corresponds to the address of a sync
253  * instruction for which there is an entry in the exception
254  * table.
255  * Note that the 601 only takes a machine check on TEA
256  * (transfer error ack) signal assertion, and does not
257  * set any of the top 16 bits of SRR1.
258  *  -- paulus.
259  */
260 static inline int check_io_access(struct pt_regs *regs)
261 {
262 #ifdef CONFIG_PPC32
263 	unsigned long msr = regs->msr;
264 	const struct exception_table_entry *entry;
265 	unsigned int *nip = (unsigned int *)regs->nip;
266 
267 	if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
268 	    && (entry = search_exception_tables(regs->nip)) != NULL) {
269 		/*
270 		 * Check that it's a sync instruction, or somewhere
271 		 * in the twi; isync; nop sequence that inb/inw/inl uses.
272 		 * As the address is in the exception table
273 		 * we should be able to read the instr there.
274 		 * For the debug message, we look at the preceding
275 		 * load or store.
276 		 */
277 		if (*nip == 0x60000000)		/* nop */
278 			nip -= 2;
279 		else if (*nip == 0x4c00012c)	/* isync */
280 			--nip;
281 		if (*nip == 0x7c0004ac || (*nip >> 26) == 3) {
282 			/* sync or twi */
283 			unsigned int rb;
284 
285 			--nip;
286 			rb = (*nip >> 11) & 0x1f;
287 			printk(KERN_DEBUG "%s bad port %lx at %p\n",
288 			       (*nip & 0x100)? "OUT to": "IN from",
289 			       regs->gpr[rb] - _IO_BASE, nip);
290 			regs->msr |= MSR_RI;
291 			regs->nip = entry->fixup;
292 			return 1;
293 		}
294 	}
295 #endif /* CONFIG_PPC32 */
296 	return 0;
297 }
298 
299 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
300 /* On 4xx, the reason for the machine check or program exception
301    is in the ESR. */
302 #define get_reason(regs)	((regs)->dsisr)
303 #ifndef CONFIG_FSL_BOOKE
304 #define get_mc_reason(regs)	((regs)->dsisr)
305 #else
306 #define get_mc_reason(regs)	(mfspr(SPRN_MCSR))
307 #endif
308 #define REASON_FP		ESR_FP
309 #define REASON_ILLEGAL		(ESR_PIL | ESR_PUO)
310 #define REASON_PRIVILEGED	ESR_PPR
311 #define REASON_TRAP		ESR_PTR
312 
313 /* single-step stuff */
314 #define single_stepping(regs)	(current->thread.dbcr0 & DBCR0_IC)
315 #define clear_single_step(regs)	(current->thread.dbcr0 &= ~DBCR0_IC)
316 
317 #else
318 /* On non-4xx, the reason for the machine check or program
319    exception is in the MSR. */
320 #define get_reason(regs)	((regs)->msr)
321 #define get_mc_reason(regs)	((regs)->msr)
322 #define REASON_FP		0x100000
323 #define REASON_ILLEGAL		0x80000
324 #define REASON_PRIVILEGED	0x40000
325 #define REASON_TRAP		0x20000
326 
327 #define single_stepping(regs)	((regs)->msr & MSR_SE)
328 #define clear_single_step(regs)	((regs)->msr &= ~MSR_SE)
329 #endif
330 
331 #if defined(CONFIG_4xx)
332 int machine_check_4xx(struct pt_regs *regs)
333 {
334 	unsigned long reason = get_mc_reason(regs);
335 
336 	if (reason & ESR_IMCP) {
337 		printk("Instruction");
338 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
339 	} else
340 		printk("Data");
341 	printk(" machine check in kernel mode.\n");
342 
343 	return 0;
344 }
345 
346 int machine_check_440A(struct pt_regs *regs)
347 {
348 	unsigned long reason = get_mc_reason(regs);
349 
350 	printk("Machine check in kernel mode.\n");
351 	if (reason & ESR_IMCP){
352 		printk("Instruction Synchronous Machine Check exception\n");
353 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
354 	}
355 	else {
356 		u32 mcsr = mfspr(SPRN_MCSR);
357 		if (mcsr & MCSR_IB)
358 			printk("Instruction Read PLB Error\n");
359 		if (mcsr & MCSR_DRB)
360 			printk("Data Read PLB Error\n");
361 		if (mcsr & MCSR_DWB)
362 			printk("Data Write PLB Error\n");
363 		if (mcsr & MCSR_TLBP)
364 			printk("TLB Parity Error\n");
365 		if (mcsr & MCSR_ICP){
366 			flush_instruction_cache();
367 			printk("I-Cache Parity Error\n");
368 		}
369 		if (mcsr & MCSR_DCSP)
370 			printk("D-Cache Search Parity Error\n");
371 		if (mcsr & MCSR_DCFP)
372 			printk("D-Cache Flush Parity Error\n");
373 		if (mcsr & MCSR_IMPE)
374 			printk("Machine Check exception is imprecise\n");
375 
376 		/* Clear MCSR */
377 		mtspr(SPRN_MCSR, mcsr);
378 	}
379 	return 0;
380 }
381 
382 int machine_check_47x(struct pt_regs *regs)
383 {
384 	unsigned long reason = get_mc_reason(regs);
385 	u32 mcsr;
386 
387 	printk(KERN_ERR "Machine check in kernel mode.\n");
388 	if (reason & ESR_IMCP) {
389 		printk(KERN_ERR
390 		       "Instruction Synchronous Machine Check exception\n");
391 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
392 		return 0;
393 	}
394 	mcsr = mfspr(SPRN_MCSR);
395 	if (mcsr & MCSR_IB)
396 		printk(KERN_ERR "Instruction Read PLB Error\n");
397 	if (mcsr & MCSR_DRB)
398 		printk(KERN_ERR "Data Read PLB Error\n");
399 	if (mcsr & MCSR_DWB)
400 		printk(KERN_ERR "Data Write PLB Error\n");
401 	if (mcsr & MCSR_TLBP)
402 		printk(KERN_ERR "TLB Parity Error\n");
403 	if (mcsr & MCSR_ICP) {
404 		flush_instruction_cache();
405 		printk(KERN_ERR "I-Cache Parity Error\n");
406 	}
407 	if (mcsr & MCSR_DCSP)
408 		printk(KERN_ERR "D-Cache Search Parity Error\n");
409 	if (mcsr & PPC47x_MCSR_GPR)
410 		printk(KERN_ERR "GPR Parity Error\n");
411 	if (mcsr & PPC47x_MCSR_FPR)
412 		printk(KERN_ERR "FPR Parity Error\n");
413 	if (mcsr & PPC47x_MCSR_IPR)
414 		printk(KERN_ERR "Machine Check exception is imprecise\n");
415 
416 	/* Clear MCSR */
417 	mtspr(SPRN_MCSR, mcsr);
418 
419 	return 0;
420 }
421 #elif defined(CONFIG_E500)
422 int machine_check_e500mc(struct pt_regs *regs)
423 {
424 	unsigned long mcsr = mfspr(SPRN_MCSR);
425 	unsigned long reason = mcsr;
426 	int recoverable = 1;
427 
428 	if (reason & MCSR_BUS_RBERR) {
429 		recoverable = fsl_rio_mcheck_exception(regs);
430 		if (recoverable == 1)
431 			goto silent_out;
432 	}
433 
434 	printk("Machine check in kernel mode.\n");
435 	printk("Caused by (from MCSR=%lx): ", reason);
436 
437 	if (reason & MCSR_MCP)
438 		printk("Machine Check Signal\n");
439 
440 	if (reason & MCSR_ICPERR) {
441 		printk("Instruction Cache Parity Error\n");
442 
443 		/*
444 		 * This is recoverable by invalidating the i-cache.
445 		 */
446 		mtspr(SPRN_L1CSR1, mfspr(SPRN_L1CSR1) | L1CSR1_ICFI);
447 		while (mfspr(SPRN_L1CSR1) & L1CSR1_ICFI)
448 			;
449 
450 		/*
451 		 * This will generally be accompanied by an instruction
452 		 * fetch error report -- only treat MCSR_IF as fatal
453 		 * if it wasn't due to an L1 parity error.
454 		 */
455 		reason &= ~MCSR_IF;
456 	}
457 
458 	if (reason & MCSR_DCPERR_MC) {
459 		printk("Data Cache Parity Error\n");
460 		recoverable = 0;
461 	}
462 
463 	if (reason & MCSR_L2MMU_MHIT) {
464 		printk("Hit on multiple TLB entries\n");
465 		recoverable = 0;
466 	}
467 
468 	if (reason & MCSR_NMI)
469 		printk("Non-maskable interrupt\n");
470 
471 	if (reason & MCSR_IF) {
472 		printk("Instruction Fetch Error Report\n");
473 		recoverable = 0;
474 	}
475 
476 	if (reason & MCSR_LD) {
477 		printk("Load Error Report\n");
478 		recoverable = 0;
479 	}
480 
481 	if (reason & MCSR_ST) {
482 		printk("Store Error Report\n");
483 		recoverable = 0;
484 	}
485 
486 	if (reason & MCSR_LDG) {
487 		printk("Guarded Load Error Report\n");
488 		recoverable = 0;
489 	}
490 
491 	if (reason & MCSR_TLBSYNC)
492 		printk("Simultaneous tlbsync operations\n");
493 
494 	if (reason & MCSR_BSL2_ERR) {
495 		printk("Level 2 Cache Error\n");
496 		recoverable = 0;
497 	}
498 
499 	if (reason & MCSR_MAV) {
500 		u64 addr;
501 
502 		addr = mfspr(SPRN_MCAR);
503 		addr |= (u64)mfspr(SPRN_MCARU) << 32;
504 
505 		printk("Machine Check %s Address: %#llx\n",
506 		       reason & MCSR_MEA ? "Effective" : "Physical", addr);
507 	}
508 
509 silent_out:
510 	mtspr(SPRN_MCSR, mcsr);
511 	return mfspr(SPRN_MCSR) == 0 && recoverable;
512 }
513 
514 int machine_check_e500(struct pt_regs *regs)
515 {
516 	unsigned long reason = get_mc_reason(regs);
517 
518 	if (reason & MCSR_BUS_RBERR) {
519 		if (fsl_rio_mcheck_exception(regs))
520 			return 1;
521 	}
522 
523 	printk("Machine check in kernel mode.\n");
524 	printk("Caused by (from MCSR=%lx): ", reason);
525 
526 	if (reason & MCSR_MCP)
527 		printk("Machine Check Signal\n");
528 	if (reason & MCSR_ICPERR)
529 		printk("Instruction Cache Parity Error\n");
530 	if (reason & MCSR_DCP_PERR)
531 		printk("Data Cache Push Parity Error\n");
532 	if (reason & MCSR_DCPERR)
533 		printk("Data Cache Parity Error\n");
534 	if (reason & MCSR_BUS_IAERR)
535 		printk("Bus - Instruction Address Error\n");
536 	if (reason & MCSR_BUS_RAERR)
537 		printk("Bus - Read Address Error\n");
538 	if (reason & MCSR_BUS_WAERR)
539 		printk("Bus - Write Address Error\n");
540 	if (reason & MCSR_BUS_IBERR)
541 		printk("Bus - Instruction Data Error\n");
542 	if (reason & MCSR_BUS_RBERR)
543 		printk("Bus - Read Data Bus Error\n");
544 	if (reason & MCSR_BUS_WBERR)
545 		printk("Bus - Read Data Bus Error\n");
546 	if (reason & MCSR_BUS_IPERR)
547 		printk("Bus - Instruction Parity Error\n");
548 	if (reason & MCSR_BUS_RPERR)
549 		printk("Bus - Read Parity Error\n");
550 
551 	return 0;
552 }
553 
554 int machine_check_generic(struct pt_regs *regs)
555 {
556 	return 0;
557 }
558 #elif defined(CONFIG_E200)
559 int machine_check_e200(struct pt_regs *regs)
560 {
561 	unsigned long reason = get_mc_reason(regs);
562 
563 	printk("Machine check in kernel mode.\n");
564 	printk("Caused by (from MCSR=%lx): ", reason);
565 
566 	if (reason & MCSR_MCP)
567 		printk("Machine Check Signal\n");
568 	if (reason & MCSR_CP_PERR)
569 		printk("Cache Push Parity Error\n");
570 	if (reason & MCSR_CPERR)
571 		printk("Cache Parity Error\n");
572 	if (reason & MCSR_EXCP_ERR)
573 		printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
574 	if (reason & MCSR_BUS_IRERR)
575 		printk("Bus - Read Bus Error on instruction fetch\n");
576 	if (reason & MCSR_BUS_DRERR)
577 		printk("Bus - Read Bus Error on data load\n");
578 	if (reason & MCSR_BUS_WRERR)
579 		printk("Bus - Write Bus Error on buffered store or cache line push\n");
580 
581 	return 0;
582 }
583 #else
584 int machine_check_generic(struct pt_regs *regs)
585 {
586 	unsigned long reason = get_mc_reason(regs);
587 
588 	printk("Machine check in kernel mode.\n");
589 	printk("Caused by (from SRR1=%lx): ", reason);
590 	switch (reason & 0x601F0000) {
591 	case 0x80000:
592 		printk("Machine check signal\n");
593 		break;
594 	case 0:		/* for 601 */
595 	case 0x40000:
596 	case 0x140000:	/* 7450 MSS error and TEA */
597 		printk("Transfer error ack signal\n");
598 		break;
599 	case 0x20000:
600 		printk("Data parity error signal\n");
601 		break;
602 	case 0x10000:
603 		printk("Address parity error signal\n");
604 		break;
605 	case 0x20000000:
606 		printk("L1 Data Cache error\n");
607 		break;
608 	case 0x40000000:
609 		printk("L1 Instruction Cache error\n");
610 		break;
611 	case 0x00100000:
612 		printk("L2 data cache parity error\n");
613 		break;
614 	default:
615 		printk("Unknown values in msr\n");
616 	}
617 	return 0;
618 }
619 #endif /* everything else */
620 
621 void machine_check_exception(struct pt_regs *regs)
622 {
623 	int recover = 0;
624 
625 	__get_cpu_var(irq_stat).mce_exceptions++;
626 
627 	/* See if any machine dependent calls. In theory, we would want
628 	 * to call the CPU first, and call the ppc_md. one if the CPU
629 	 * one returns a positive number. However there is existing code
630 	 * that assumes the board gets a first chance, so let's keep it
631 	 * that way for now and fix things later. --BenH.
632 	 */
633 	if (ppc_md.machine_check_exception)
634 		recover = ppc_md.machine_check_exception(regs);
635 	else if (cur_cpu_spec->machine_check)
636 		recover = cur_cpu_spec->machine_check(regs);
637 
638 	if (recover > 0)
639 		return;
640 
641 #if defined(CONFIG_8xx) && defined(CONFIG_PCI)
642 	/* the qspan pci read routines can cause machine checks -- Cort
643 	 *
644 	 * yuck !!! that totally needs to go away ! There are better ways
645 	 * to deal with that than having a wart in the mcheck handler.
646 	 * -- BenH
647 	 */
648 	bad_page_fault(regs, regs->dar, SIGBUS);
649 	return;
650 #endif
651 
652 	if (debugger_fault_handler(regs))
653 		return;
654 
655 	if (check_io_access(regs))
656 		return;
657 
658 	die("Machine check", regs, SIGBUS);
659 
660 	/* Must die if the interrupt is not recoverable */
661 	if (!(regs->msr & MSR_RI))
662 		panic("Unrecoverable Machine check");
663 }
664 
665 void SMIException(struct pt_regs *regs)
666 {
667 	die("System Management Interrupt", regs, SIGABRT);
668 }
669 
670 void unknown_exception(struct pt_regs *regs)
671 {
672 	printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
673 	       regs->nip, regs->msr, regs->trap);
674 
675 	_exception(SIGTRAP, regs, 0, 0);
676 }
677 
678 void instruction_breakpoint_exception(struct pt_regs *regs)
679 {
680 	if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
681 					5, SIGTRAP) == NOTIFY_STOP)
682 		return;
683 	if (debugger_iabr_match(regs))
684 		return;
685 	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
686 }
687 
688 void RunModeException(struct pt_regs *regs)
689 {
690 	_exception(SIGTRAP, regs, 0, 0);
691 }
692 
693 void __kprobes single_step_exception(struct pt_regs *regs)
694 {
695 	clear_single_step(regs);
696 
697 	if (notify_die(DIE_SSTEP, "single_step", regs, 5,
698 					5, SIGTRAP) == NOTIFY_STOP)
699 		return;
700 	if (debugger_sstep(regs))
701 		return;
702 
703 	_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
704 }
705 
706 /*
707  * After we have successfully emulated an instruction, we have to
708  * check if the instruction was being single-stepped, and if so,
709  * pretend we got a single-step exception.  This was pointed out
710  * by Kumar Gala.  -- paulus
711  */
712 static void emulate_single_step(struct pt_regs *regs)
713 {
714 	if (single_stepping(regs))
715 		single_step_exception(regs);
716 }
717 
718 static inline int __parse_fpscr(unsigned long fpscr)
719 {
720 	int ret = 0;
721 
722 	/* Invalid operation */
723 	if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
724 		ret = FPE_FLTINV;
725 
726 	/* Overflow */
727 	else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
728 		ret = FPE_FLTOVF;
729 
730 	/* Underflow */
731 	else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
732 		ret = FPE_FLTUND;
733 
734 	/* Divide by zero */
735 	else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
736 		ret = FPE_FLTDIV;
737 
738 	/* Inexact result */
739 	else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
740 		ret = FPE_FLTRES;
741 
742 	return ret;
743 }
744 
745 static void parse_fpe(struct pt_regs *regs)
746 {
747 	int code = 0;
748 
749 	flush_fp_to_thread(current);
750 
751 	code = __parse_fpscr(current->thread.fpscr.val);
752 
753 	_exception(SIGFPE, regs, code, regs->nip);
754 }
755 
756 /*
757  * Illegal instruction emulation support.  Originally written to
758  * provide the PVR to user applications using the mfspr rd, PVR.
759  * Return non-zero if we can't emulate, or -EFAULT if the associated
760  * memory access caused an access fault.  Return zero on success.
761  *
762  * There are a couple of ways to do this, either "decode" the instruction
763  * or directly match lots of bits.  In this case, matching lots of
764  * bits is faster and easier.
765  *
766  */
767 static int emulate_string_inst(struct pt_regs *regs, u32 instword)
768 {
769 	u8 rT = (instword >> 21) & 0x1f;
770 	u8 rA = (instword >> 16) & 0x1f;
771 	u8 NB_RB = (instword >> 11) & 0x1f;
772 	u32 num_bytes;
773 	unsigned long EA;
774 	int pos = 0;
775 
776 	/* Early out if we are an invalid form of lswx */
777 	if ((instword & PPC_INST_STRING_MASK) == PPC_INST_LSWX)
778 		if ((rT == rA) || (rT == NB_RB))
779 			return -EINVAL;
780 
781 	EA = (rA == 0) ? 0 : regs->gpr[rA];
782 
783 	switch (instword & PPC_INST_STRING_MASK) {
784 		case PPC_INST_LSWX:
785 		case PPC_INST_STSWX:
786 			EA += NB_RB;
787 			num_bytes = regs->xer & 0x7f;
788 			break;
789 		case PPC_INST_LSWI:
790 		case PPC_INST_STSWI:
791 			num_bytes = (NB_RB == 0) ? 32 : NB_RB;
792 			break;
793 		default:
794 			return -EINVAL;
795 	}
796 
797 	while (num_bytes != 0)
798 	{
799 		u8 val;
800 		u32 shift = 8 * (3 - (pos & 0x3));
801 
802 		switch ((instword & PPC_INST_STRING_MASK)) {
803 			case PPC_INST_LSWX:
804 			case PPC_INST_LSWI:
805 				if (get_user(val, (u8 __user *)EA))
806 					return -EFAULT;
807 				/* first time updating this reg,
808 				 * zero it out */
809 				if (pos == 0)
810 					regs->gpr[rT] = 0;
811 				regs->gpr[rT] |= val << shift;
812 				break;
813 			case PPC_INST_STSWI:
814 			case PPC_INST_STSWX:
815 				val = regs->gpr[rT] >> shift;
816 				if (put_user(val, (u8 __user *)EA))
817 					return -EFAULT;
818 				break;
819 		}
820 		/* move EA to next address */
821 		EA += 1;
822 		num_bytes--;
823 
824 		/* manage our position within the register */
825 		if (++pos == 4) {
826 			pos = 0;
827 			if (++rT == 32)
828 				rT = 0;
829 		}
830 	}
831 
832 	return 0;
833 }
834 
835 static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword)
836 {
837 	u32 ra,rs;
838 	unsigned long tmp;
839 
840 	ra = (instword >> 16) & 0x1f;
841 	rs = (instword >> 21) & 0x1f;
842 
843 	tmp = regs->gpr[rs];
844 	tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL);
845 	tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL);
846 	tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
847 	regs->gpr[ra] = tmp;
848 
849 	return 0;
850 }
851 
852 static int emulate_isel(struct pt_regs *regs, u32 instword)
853 {
854 	u8 rT = (instword >> 21) & 0x1f;
855 	u8 rA = (instword >> 16) & 0x1f;
856 	u8 rB = (instword >> 11) & 0x1f;
857 	u8 BC = (instword >> 6) & 0x1f;
858 	u8 bit;
859 	unsigned long tmp;
860 
861 	tmp = (rA == 0) ? 0 : regs->gpr[rA];
862 	bit = (regs->ccr >> (31 - BC)) & 0x1;
863 
864 	regs->gpr[rT] = bit ? tmp : regs->gpr[rB];
865 
866 	return 0;
867 }
868 
869 static int emulate_instruction(struct pt_regs *regs)
870 {
871 	u32 instword;
872 	u32 rd;
873 
874 	if (!user_mode(regs) || (regs->msr & MSR_LE))
875 		return -EINVAL;
876 	CHECK_FULL_REGS(regs);
877 
878 	if (get_user(instword, (u32 __user *)(regs->nip)))
879 		return -EFAULT;
880 
881 	/* Emulate the mfspr rD, PVR. */
882 	if ((instword & PPC_INST_MFSPR_PVR_MASK) == PPC_INST_MFSPR_PVR) {
883 		PPC_WARN_EMULATED(mfpvr, regs);
884 		rd = (instword >> 21) & 0x1f;
885 		regs->gpr[rd] = mfspr(SPRN_PVR);
886 		return 0;
887 	}
888 
889 	/* Emulating the dcba insn is just a no-op.  */
890 	if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA) {
891 		PPC_WARN_EMULATED(dcba, regs);
892 		return 0;
893 	}
894 
895 	/* Emulate the mcrxr insn.  */
896 	if ((instword & PPC_INST_MCRXR_MASK) == PPC_INST_MCRXR) {
897 		int shift = (instword >> 21) & 0x1c;
898 		unsigned long msk = 0xf0000000UL >> shift;
899 
900 		PPC_WARN_EMULATED(mcrxr, regs);
901 		regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
902 		regs->xer &= ~0xf0000000UL;
903 		return 0;
904 	}
905 
906 	/* Emulate load/store string insn. */
907 	if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {
908 		PPC_WARN_EMULATED(string, regs);
909 		return emulate_string_inst(regs, instword);
910 	}
911 
912 	/* Emulate the popcntb (Population Count Bytes) instruction. */
913 	if ((instword & PPC_INST_POPCNTB_MASK) == PPC_INST_POPCNTB) {
914 		PPC_WARN_EMULATED(popcntb, regs);
915 		return emulate_popcntb_inst(regs, instword);
916 	}
917 
918 	/* Emulate isel (Integer Select) instruction */
919 	if ((instword & PPC_INST_ISEL_MASK) == PPC_INST_ISEL) {
920 		PPC_WARN_EMULATED(isel, regs);
921 		return emulate_isel(regs, instword);
922 	}
923 
924 #ifdef CONFIG_PPC64
925 	/* Emulate the mfspr rD, DSCR. */
926 	if (((instword & PPC_INST_MFSPR_DSCR_MASK) == PPC_INST_MFSPR_DSCR) &&
927 			cpu_has_feature(CPU_FTR_DSCR)) {
928 		PPC_WARN_EMULATED(mfdscr, regs);
929 		rd = (instword >> 21) & 0x1f;
930 		regs->gpr[rd] = mfspr(SPRN_DSCR);
931 		return 0;
932 	}
933 	/* Emulate the mtspr DSCR, rD. */
934 	if (((instword & PPC_INST_MTSPR_DSCR_MASK) == PPC_INST_MTSPR_DSCR) &&
935 			cpu_has_feature(CPU_FTR_DSCR)) {
936 		PPC_WARN_EMULATED(mtdscr, regs);
937 		rd = (instword >> 21) & 0x1f;
938 		mtspr(SPRN_DSCR, regs->gpr[rd]);
939 		current->thread.dscr_inherit = 1;
940 		return 0;
941 	}
942 #endif
943 
944 	return -EINVAL;
945 }
946 
947 int is_valid_bugaddr(unsigned long addr)
948 {
949 	return is_kernel_addr(addr);
950 }
951 
952 void __kprobes program_check_exception(struct pt_regs *regs)
953 {
954 	unsigned int reason = get_reason(regs);
955 	extern int do_mathemu(struct pt_regs *regs);
956 
957 	/* We can now get here via a FP Unavailable exception if the core
958 	 * has no FPU, in that case the reason flags will be 0 */
959 
960 	if (reason & REASON_FP) {
961 		/* IEEE FP exception */
962 		parse_fpe(regs);
963 		return;
964 	}
965 	if (reason & REASON_TRAP) {
966 		/* Debugger is first in line to stop recursive faults in
967 		 * rcu_lock, notify_die, or atomic_notifier_call_chain */
968 		if (debugger_bpt(regs))
969 			return;
970 
971 		/* trap exception */
972 		if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
973 				== NOTIFY_STOP)
974 			return;
975 
976 		if (!(regs->msr & MSR_PR) &&  /* not user-mode */
977 		    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
978 			regs->nip += 4;
979 			return;
980 		}
981 		_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
982 		return;
983 	}
984 
985 	local_irq_enable();
986 
987 #ifdef CONFIG_MATH_EMULATION
988 	/* (reason & REASON_ILLEGAL) would be the obvious thing here,
989 	 * but there seems to be a hardware bug on the 405GP (RevD)
990 	 * that means ESR is sometimes set incorrectly - either to
991 	 * ESR_DST (!?) or 0.  In the process of chasing this with the
992 	 * hardware people - not sure if it can happen on any illegal
993 	 * instruction or only on FP instructions, whether there is a
994 	 * pattern to occurrences etc. -dgibson 31/Mar/2003 */
995 	switch (do_mathemu(regs)) {
996 	case 0:
997 		emulate_single_step(regs);
998 		return;
999 	case 1: {
1000 			int code = 0;
1001 			code = __parse_fpscr(current->thread.fpscr.val);
1002 			_exception(SIGFPE, regs, code, regs->nip);
1003 			return;
1004 		}
1005 	case -EFAULT:
1006 		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1007 		return;
1008 	}
1009 	/* fall through on any other errors */
1010 #endif /* CONFIG_MATH_EMULATION */
1011 
1012 	/* Try to emulate it if we should. */
1013 	if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
1014 		switch (emulate_instruction(regs)) {
1015 		case 0:
1016 			regs->nip += 4;
1017 			emulate_single_step(regs);
1018 			return;
1019 		case -EFAULT:
1020 			_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1021 			return;
1022 		}
1023 	}
1024 
1025 	if (reason & REASON_PRIVILEGED)
1026 		_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1027 	else
1028 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1029 }
1030 
1031 void alignment_exception(struct pt_regs *regs)
1032 {
1033 	int sig, code, fixed = 0;
1034 
1035 	/* we don't implement logging of alignment exceptions */
1036 	if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
1037 		fixed = fix_alignment(regs);
1038 
1039 	if (fixed == 1) {
1040 		regs->nip += 4;	/* skip over emulated instruction */
1041 		emulate_single_step(regs);
1042 		return;
1043 	}
1044 
1045 	/* Operand address was bad */
1046 	if (fixed == -EFAULT) {
1047 		sig = SIGSEGV;
1048 		code = SEGV_ACCERR;
1049 	} else {
1050 		sig = SIGBUS;
1051 		code = BUS_ADRALN;
1052 	}
1053 	if (user_mode(regs))
1054 		_exception(sig, regs, code, regs->dar);
1055 	else
1056 		bad_page_fault(regs, regs->dar, sig);
1057 }
1058 
1059 void StackOverflow(struct pt_regs *regs)
1060 {
1061 	printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
1062 	       current, regs->gpr[1]);
1063 	debugger(regs);
1064 	show_regs(regs);
1065 	panic("kernel stack overflow");
1066 }
1067 
1068 void nonrecoverable_exception(struct pt_regs *regs)
1069 {
1070 	printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
1071 	       regs->nip, regs->msr);
1072 	debugger(regs);
1073 	die("nonrecoverable exception", regs, SIGKILL);
1074 }
1075 
1076 void trace_syscall(struct pt_regs *regs)
1077 {
1078 	printk("Task: %p(%d), PC: %08lX/%08lX, Syscall: %3ld, Result: %s%ld    %s\n",
1079 	       current, task_pid_nr(current), regs->nip, regs->link, regs->gpr[0],
1080 	       regs->ccr&0x10000000?"Error=":"", regs->gpr[3], print_tainted());
1081 }
1082 
1083 void kernel_fp_unavailable_exception(struct pt_regs *regs)
1084 {
1085 	printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
1086 			  "%lx at %lx\n", regs->trap, regs->nip);
1087 	die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
1088 }
1089 
1090 void altivec_unavailable_exception(struct pt_regs *regs)
1091 {
1092 	if (user_mode(regs)) {
1093 		/* A user program has executed an altivec instruction,
1094 		   but this kernel doesn't support altivec. */
1095 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1096 		return;
1097 	}
1098 
1099 	printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
1100 			"%lx at %lx\n", regs->trap, regs->nip);
1101 	die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
1102 }
1103 
1104 void vsx_unavailable_exception(struct pt_regs *regs)
1105 {
1106 	if (user_mode(regs)) {
1107 		/* A user program has executed an vsx instruction,
1108 		   but this kernel doesn't support vsx. */
1109 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1110 		return;
1111 	}
1112 
1113 	printk(KERN_EMERG "Unrecoverable VSX Unavailable Exception "
1114 			"%lx at %lx\n", regs->trap, regs->nip);
1115 	die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
1116 }
1117 
1118 void performance_monitor_exception(struct pt_regs *regs)
1119 {
1120 	__get_cpu_var(irq_stat).pmu_irqs++;
1121 
1122 	perf_irq(regs);
1123 }
1124 
1125 #ifdef CONFIG_8xx
1126 void SoftwareEmulation(struct pt_regs *regs)
1127 {
1128 	extern int do_mathemu(struct pt_regs *);
1129 	extern int Soft_emulate_8xx(struct pt_regs *);
1130 #if defined(CONFIG_MATH_EMULATION) || defined(CONFIG_8XX_MINIMAL_FPEMU)
1131 	int errcode;
1132 #endif
1133 
1134 	CHECK_FULL_REGS(regs);
1135 
1136 	if (!user_mode(regs)) {
1137 		debugger(regs);
1138 		die("Kernel Mode Software FPU Emulation", regs, SIGFPE);
1139 	}
1140 
1141 #ifdef CONFIG_MATH_EMULATION
1142 	errcode = do_mathemu(regs);
1143 	if (errcode >= 0)
1144 		PPC_WARN_EMULATED(math, regs);
1145 
1146 	switch (errcode) {
1147 	case 0:
1148 		emulate_single_step(regs);
1149 		return;
1150 	case 1: {
1151 			int code = 0;
1152 			code = __parse_fpscr(current->thread.fpscr.val);
1153 			_exception(SIGFPE, regs, code, regs->nip);
1154 			return;
1155 		}
1156 	case -EFAULT:
1157 		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1158 		return;
1159 	default:
1160 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1161 		return;
1162 	}
1163 
1164 #elif defined(CONFIG_8XX_MINIMAL_FPEMU)
1165 	errcode = Soft_emulate_8xx(regs);
1166 	if (errcode >= 0)
1167 		PPC_WARN_EMULATED(8xx, regs);
1168 
1169 	switch (errcode) {
1170 	case 0:
1171 		emulate_single_step(regs);
1172 		return;
1173 	case 1:
1174 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1175 		return;
1176 	case -EFAULT:
1177 		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1178 		return;
1179 	}
1180 #else
1181 	_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1182 #endif
1183 }
1184 #endif /* CONFIG_8xx */
1185 
1186 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1187 static void handle_debug(struct pt_regs *regs, unsigned long debug_status)
1188 {
1189 	int changed = 0;
1190 	/*
1191 	 * Determine the cause of the debug event, clear the
1192 	 * event flags and send a trap to the handler. Torez
1193 	 */
1194 	if (debug_status & (DBSR_DAC1R | DBSR_DAC1W)) {
1195 		dbcr_dac(current) &= ~(DBCR_DAC1R | DBCR_DAC1W);
1196 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
1197 		current->thread.dbcr2 &= ~DBCR2_DAC12MODE;
1198 #endif
1199 		do_send_trap(regs, mfspr(SPRN_DAC1), debug_status, TRAP_HWBKPT,
1200 			     5);
1201 		changed |= 0x01;
1202 	}  else if (debug_status & (DBSR_DAC2R | DBSR_DAC2W)) {
1203 		dbcr_dac(current) &= ~(DBCR_DAC2R | DBCR_DAC2W);
1204 		do_send_trap(regs, mfspr(SPRN_DAC2), debug_status, TRAP_HWBKPT,
1205 			     6);
1206 		changed |= 0x01;
1207 	}  else if (debug_status & DBSR_IAC1) {
1208 		current->thread.dbcr0 &= ~DBCR0_IAC1;
1209 		dbcr_iac_range(current) &= ~DBCR_IAC12MODE;
1210 		do_send_trap(regs, mfspr(SPRN_IAC1), debug_status, TRAP_HWBKPT,
1211 			     1);
1212 		changed |= 0x01;
1213 	}  else if (debug_status & DBSR_IAC2) {
1214 		current->thread.dbcr0 &= ~DBCR0_IAC2;
1215 		do_send_trap(regs, mfspr(SPRN_IAC2), debug_status, TRAP_HWBKPT,
1216 			     2);
1217 		changed |= 0x01;
1218 	}  else if (debug_status & DBSR_IAC3) {
1219 		current->thread.dbcr0 &= ~DBCR0_IAC3;
1220 		dbcr_iac_range(current) &= ~DBCR_IAC34MODE;
1221 		do_send_trap(regs, mfspr(SPRN_IAC3), debug_status, TRAP_HWBKPT,
1222 			     3);
1223 		changed |= 0x01;
1224 	}  else if (debug_status & DBSR_IAC4) {
1225 		current->thread.dbcr0 &= ~DBCR0_IAC4;
1226 		do_send_trap(regs, mfspr(SPRN_IAC4), debug_status, TRAP_HWBKPT,
1227 			     4);
1228 		changed |= 0x01;
1229 	}
1230 	/*
1231 	 * At the point this routine was called, the MSR(DE) was turned off.
1232 	 * Check all other debug flags and see if that bit needs to be turned
1233 	 * back on or not.
1234 	 */
1235 	if (DBCR_ACTIVE_EVENTS(current->thread.dbcr0, current->thread.dbcr1))
1236 		regs->msr |= MSR_DE;
1237 	else
1238 		/* Make sure the IDM flag is off */
1239 		current->thread.dbcr0 &= ~DBCR0_IDM;
1240 
1241 	if (changed & 0x01)
1242 		mtspr(SPRN_DBCR0, current->thread.dbcr0);
1243 }
1244 
1245 void __kprobes DebugException(struct pt_regs *regs, unsigned long debug_status)
1246 {
1247 	current->thread.dbsr = debug_status;
1248 
1249 	/* Hack alert: On BookE, Branch Taken stops on the branch itself, while
1250 	 * on server, it stops on the target of the branch. In order to simulate
1251 	 * the server behaviour, we thus restart right away with a single step
1252 	 * instead of stopping here when hitting a BT
1253 	 */
1254 	if (debug_status & DBSR_BT) {
1255 		regs->msr &= ~MSR_DE;
1256 
1257 		/* Disable BT */
1258 		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_BT);
1259 		/* Clear the BT event */
1260 		mtspr(SPRN_DBSR, DBSR_BT);
1261 
1262 		/* Do the single step trick only when coming from userspace */
1263 		if (user_mode(regs)) {
1264 			current->thread.dbcr0 &= ~DBCR0_BT;
1265 			current->thread.dbcr0 |= DBCR0_IDM | DBCR0_IC;
1266 			regs->msr |= MSR_DE;
1267 			return;
1268 		}
1269 
1270 		if (notify_die(DIE_SSTEP, "block_step", regs, 5,
1271 			       5, SIGTRAP) == NOTIFY_STOP) {
1272 			return;
1273 		}
1274 		if (debugger_sstep(regs))
1275 			return;
1276 	} else if (debug_status & DBSR_IC) { 	/* Instruction complete */
1277 		regs->msr &= ~MSR_DE;
1278 
1279 		/* Disable instruction completion */
1280 		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
1281 		/* Clear the instruction completion event */
1282 		mtspr(SPRN_DBSR, DBSR_IC);
1283 
1284 		if (notify_die(DIE_SSTEP, "single_step", regs, 5,
1285 			       5, SIGTRAP) == NOTIFY_STOP) {
1286 			return;
1287 		}
1288 
1289 		if (debugger_sstep(regs))
1290 			return;
1291 
1292 		if (user_mode(regs)) {
1293 			current->thread.dbcr0 &= ~DBCR0_IC;
1294 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1295 			if (DBCR_ACTIVE_EVENTS(current->thread.dbcr0,
1296 					       current->thread.dbcr1))
1297 				regs->msr |= MSR_DE;
1298 			else
1299 				/* Make sure the IDM bit is off */
1300 				current->thread.dbcr0 &= ~DBCR0_IDM;
1301 #endif
1302 		}
1303 
1304 		_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
1305 	} else
1306 		handle_debug(regs, debug_status);
1307 }
1308 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
1309 
1310 #if !defined(CONFIG_TAU_INT)
1311 void TAUException(struct pt_regs *regs)
1312 {
1313 	printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
1314 	       regs->nip, regs->msr, regs->trap, print_tainted());
1315 }
1316 #endif /* CONFIG_INT_TAU */
1317 
1318 #ifdef CONFIG_ALTIVEC
1319 void altivec_assist_exception(struct pt_regs *regs)
1320 {
1321 	int err;
1322 
1323 	if (!user_mode(regs)) {
1324 		printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
1325 		       " at %lx\n", regs->nip);
1326 		die("Kernel VMX/Altivec assist exception", regs, SIGILL);
1327 	}
1328 
1329 	flush_altivec_to_thread(current);
1330 
1331 	PPC_WARN_EMULATED(altivec, regs);
1332 	err = emulate_altivec(regs);
1333 	if (err == 0) {
1334 		regs->nip += 4;		/* skip emulated instruction */
1335 		emulate_single_step(regs);
1336 		return;
1337 	}
1338 
1339 	if (err == -EFAULT) {
1340 		/* got an error reading the instruction */
1341 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1342 	} else {
1343 		/* didn't recognize the instruction */
1344 		/* XXX quick hack for now: set the non-Java bit in the VSCR */
1345 		if (printk_ratelimit())
1346 			printk(KERN_ERR "Unrecognized altivec instruction "
1347 			       "in %s at %lx\n", current->comm, regs->nip);
1348 		current->thread.vscr.u[3] |= 0x10000;
1349 	}
1350 }
1351 #endif /* CONFIG_ALTIVEC */
1352 
1353 #ifdef CONFIG_VSX
1354 void vsx_assist_exception(struct pt_regs *regs)
1355 {
1356 	if (!user_mode(regs)) {
1357 		printk(KERN_EMERG "VSX assist exception in kernel mode"
1358 		       " at %lx\n", regs->nip);
1359 		die("Kernel VSX assist exception", regs, SIGILL);
1360 	}
1361 
1362 	flush_vsx_to_thread(current);
1363 	printk(KERN_INFO "VSX assist not supported at %lx\n", regs->nip);
1364 	_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1365 }
1366 #endif /* CONFIG_VSX */
1367 
1368 #ifdef CONFIG_FSL_BOOKE
1369 void CacheLockingException(struct pt_regs *regs, unsigned long address,
1370 			   unsigned long error_code)
1371 {
1372 	/* We treat cache locking instructions from the user
1373 	 * as priv ops, in the future we could try to do
1374 	 * something smarter
1375 	 */
1376 	if (error_code & (ESR_DLK|ESR_ILK))
1377 		_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1378 	return;
1379 }
1380 #endif /* CONFIG_FSL_BOOKE */
1381 
1382 #ifdef CONFIG_SPE
1383 void SPEFloatingPointException(struct pt_regs *regs)
1384 {
1385 	extern int do_spe_mathemu(struct pt_regs *regs);
1386 	unsigned long spefscr;
1387 	int fpexc_mode;
1388 	int code = 0;
1389 	int err;
1390 
1391 	preempt_disable();
1392 	if (regs->msr & MSR_SPE)
1393 		giveup_spe(current);
1394 	preempt_enable();
1395 
1396 	spefscr = current->thread.spefscr;
1397 	fpexc_mode = current->thread.fpexc_mode;
1398 
1399 	if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
1400 		code = FPE_FLTOVF;
1401 	}
1402 	else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
1403 		code = FPE_FLTUND;
1404 	}
1405 	else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
1406 		code = FPE_FLTDIV;
1407 	else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
1408 		code = FPE_FLTINV;
1409 	}
1410 	else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
1411 		code = FPE_FLTRES;
1412 
1413 	err = do_spe_mathemu(regs);
1414 	if (err == 0) {
1415 		regs->nip += 4;		/* skip emulated instruction */
1416 		emulate_single_step(regs);
1417 		return;
1418 	}
1419 
1420 	if (err == -EFAULT) {
1421 		/* got an error reading the instruction */
1422 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1423 	} else if (err == -EINVAL) {
1424 		/* didn't recognize the instruction */
1425 		printk(KERN_ERR "unrecognized spe instruction "
1426 		       "in %s at %lx\n", current->comm, regs->nip);
1427 	} else {
1428 		_exception(SIGFPE, regs, code, regs->nip);
1429 	}
1430 
1431 	return;
1432 }
1433 
1434 void SPEFloatingPointRoundException(struct pt_regs *regs)
1435 {
1436 	extern int speround_handler(struct pt_regs *regs);
1437 	int err;
1438 
1439 	preempt_disable();
1440 	if (regs->msr & MSR_SPE)
1441 		giveup_spe(current);
1442 	preempt_enable();
1443 
1444 	regs->nip -= 4;
1445 	err = speround_handler(regs);
1446 	if (err == 0) {
1447 		regs->nip += 4;		/* skip emulated instruction */
1448 		emulate_single_step(regs);
1449 		return;
1450 	}
1451 
1452 	if (err == -EFAULT) {
1453 		/* got an error reading the instruction */
1454 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1455 	} else if (err == -EINVAL) {
1456 		/* didn't recognize the instruction */
1457 		printk(KERN_ERR "unrecognized spe instruction "
1458 		       "in %s at %lx\n", current->comm, regs->nip);
1459 	} else {
1460 		_exception(SIGFPE, regs, 0, regs->nip);
1461 		return;
1462 	}
1463 }
1464 #endif
1465 
1466 /*
1467  * We enter here if we get an unrecoverable exception, that is, one
1468  * that happened at a point where the RI (recoverable interrupt) bit
1469  * in the MSR is 0.  This indicates that SRR0/1 are live, and that
1470  * we therefore lost state by taking this exception.
1471  */
1472 void unrecoverable_exception(struct pt_regs *regs)
1473 {
1474 	printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
1475 	       regs->trap, regs->nip);
1476 	die("Unrecoverable exception", regs, SIGABRT);
1477 }
1478 
1479 #ifdef CONFIG_BOOKE_WDT
1480 /*
1481  * Default handler for a Watchdog exception,
1482  * spins until a reboot occurs
1483  */
1484 void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
1485 {
1486 	/* Generic WatchdogHandler, implement your own */
1487 	mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
1488 	return;
1489 }
1490 
1491 void WatchdogException(struct pt_regs *regs)
1492 {
1493 	printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
1494 	WatchdogHandler(regs);
1495 }
1496 #endif
1497 
1498 /*
1499  * We enter here if we discover during exception entry that we are
1500  * running in supervisor mode with a userspace value in the stack pointer.
1501  */
1502 void kernel_bad_stack(struct pt_regs *regs)
1503 {
1504 	printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
1505 	       regs->gpr[1], regs->nip);
1506 	die("Bad kernel stack pointer", regs, SIGABRT);
1507 }
1508 
1509 void __init trap_init(void)
1510 {
1511 }
1512 
1513 
1514 #ifdef CONFIG_PPC_EMULATED_STATS
1515 
1516 #define WARN_EMULATED_SETUP(type)	.type = { .name = #type }
1517 
1518 struct ppc_emulated ppc_emulated = {
1519 #ifdef CONFIG_ALTIVEC
1520 	WARN_EMULATED_SETUP(altivec),
1521 #endif
1522 	WARN_EMULATED_SETUP(dcba),
1523 	WARN_EMULATED_SETUP(dcbz),
1524 	WARN_EMULATED_SETUP(fp_pair),
1525 	WARN_EMULATED_SETUP(isel),
1526 	WARN_EMULATED_SETUP(mcrxr),
1527 	WARN_EMULATED_SETUP(mfpvr),
1528 	WARN_EMULATED_SETUP(multiple),
1529 	WARN_EMULATED_SETUP(popcntb),
1530 	WARN_EMULATED_SETUP(spe),
1531 	WARN_EMULATED_SETUP(string),
1532 	WARN_EMULATED_SETUP(unaligned),
1533 #ifdef CONFIG_MATH_EMULATION
1534 	WARN_EMULATED_SETUP(math),
1535 #elif defined(CONFIG_8XX_MINIMAL_FPEMU)
1536 	WARN_EMULATED_SETUP(8xx),
1537 #endif
1538 #ifdef CONFIG_VSX
1539 	WARN_EMULATED_SETUP(vsx),
1540 #endif
1541 #ifdef CONFIG_PPC64
1542 	WARN_EMULATED_SETUP(mfdscr),
1543 	WARN_EMULATED_SETUP(mtdscr),
1544 #endif
1545 };
1546 
1547 u32 ppc_warn_emulated;
1548 
1549 void ppc_warn_emulated_print(const char *type)
1550 {
1551 	if (printk_ratelimit())
1552 		pr_warning("%s used emulated %s instruction\n", current->comm,
1553 			   type);
1554 }
1555 
1556 static int __init ppc_warn_emulated_init(void)
1557 {
1558 	struct dentry *dir, *d;
1559 	unsigned int i;
1560 	struct ppc_emulated_entry *entries = (void *)&ppc_emulated;
1561 
1562 	if (!powerpc_debugfs_root)
1563 		return -ENODEV;
1564 
1565 	dir = debugfs_create_dir("emulated_instructions",
1566 				 powerpc_debugfs_root);
1567 	if (!dir)
1568 		return -ENOMEM;
1569 
1570 	d = debugfs_create_u32("do_warn", S_IRUGO | S_IWUSR, dir,
1571 			       &ppc_warn_emulated);
1572 	if (!d)
1573 		goto fail;
1574 
1575 	for (i = 0; i < sizeof(ppc_emulated)/sizeof(*entries); i++) {
1576 		d = debugfs_create_u32(entries[i].name, S_IRUGO | S_IWUSR, dir,
1577 				       (u32 *)&entries[i].val.counter);
1578 		if (!d)
1579 			goto fail;
1580 	}
1581 
1582 	return 0;
1583 
1584 fail:
1585 	debugfs_remove_recursive(dir);
1586 	return -ENOMEM;
1587 }
1588 
1589 device_initcall(ppc_warn_emulated_init);
1590 
1591 #endif /* CONFIG_PPC_EMULATED_STATS */
1592