xref: /openbmc/linux/arch/powerpc/kernel/traps.c (revision bc5aa3a0)
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/extable.h>
29 #include <linux/module.h>	/* print_modules */
30 #include <linux/prctl.h>
31 #include <linux/delay.h>
32 #include <linux/kprobes.h>
33 #include <linux/kexec.h>
34 #include <linux/backlight.h>
35 #include <linux/bug.h>
36 #include <linux/kdebug.h>
37 #include <linux/debugfs.h>
38 #include <linux/ratelimit.h>
39 #include <linux/context_tracking.h>
40 
41 #include <asm/emulated_ops.h>
42 #include <asm/pgtable.h>
43 #include <asm/uaccess.h>
44 #include <asm/io.h>
45 #include <asm/machdep.h>
46 #include <asm/rtas.h>
47 #include <asm/pmc.h>
48 #include <asm/reg.h>
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 #include <asm/tm.h>
56 #endif
57 #include <asm/kexec.h>
58 #include <asm/ppc-opcode.h>
59 #include <asm/rio.h>
60 #include <asm/fadump.h>
61 #include <asm/switch_to.h>
62 #include <asm/tm.h>
63 #include <asm/debug.h>
64 #include <asm/asm-prototypes.h>
65 #include <asm/hmi.h>
66 #include <sysdev/fsl_pci.h>
67 
68 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
69 int (*__debugger)(struct pt_regs *regs) __read_mostly;
70 int (*__debugger_ipi)(struct pt_regs *regs) __read_mostly;
71 int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
72 int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
73 int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
74 int (*__debugger_break_match)(struct pt_regs *regs) __read_mostly;
75 int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;
76 
77 EXPORT_SYMBOL(__debugger);
78 EXPORT_SYMBOL(__debugger_ipi);
79 EXPORT_SYMBOL(__debugger_bpt);
80 EXPORT_SYMBOL(__debugger_sstep);
81 EXPORT_SYMBOL(__debugger_iabr_match);
82 EXPORT_SYMBOL(__debugger_break_match);
83 EXPORT_SYMBOL(__debugger_fault_handler);
84 #endif
85 
86 /* Transactional Memory trap debug */
87 #ifdef TM_DEBUG_SW
88 #define TM_DEBUG(x...) printk(KERN_INFO x)
89 #else
90 #define TM_DEBUG(x...) do { } while(0)
91 #endif
92 
93 /*
94  * Trap & Exception support
95  */
96 
97 #ifdef CONFIG_PMAC_BACKLIGHT
98 static void pmac_backlight_unblank(void)
99 {
100 	mutex_lock(&pmac_backlight_mutex);
101 	if (pmac_backlight) {
102 		struct backlight_properties *props;
103 
104 		props = &pmac_backlight->props;
105 		props->brightness = props->max_brightness;
106 		props->power = FB_BLANK_UNBLANK;
107 		backlight_update_status(pmac_backlight);
108 	}
109 	mutex_unlock(&pmac_backlight_mutex);
110 }
111 #else
112 static inline void pmac_backlight_unblank(void) { }
113 #endif
114 
115 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
116 static int die_owner = -1;
117 static unsigned int die_nest_count;
118 static int die_counter;
119 
120 static unsigned __kprobes long oops_begin(struct pt_regs *regs)
121 {
122 	int cpu;
123 	unsigned long flags;
124 
125 	if (debugger(regs))
126 		return 1;
127 
128 	oops_enter();
129 
130 	/* racy, but better than risking deadlock. */
131 	raw_local_irq_save(flags);
132 	cpu = smp_processor_id();
133 	if (!arch_spin_trylock(&die_lock)) {
134 		if (cpu == die_owner)
135 			/* nested oops. should stop eventually */;
136 		else
137 			arch_spin_lock(&die_lock);
138 	}
139 	die_nest_count++;
140 	die_owner = cpu;
141 	console_verbose();
142 	bust_spinlocks(1);
143 	if (machine_is(powermac))
144 		pmac_backlight_unblank();
145 	return flags;
146 }
147 
148 static void __kprobes oops_end(unsigned long flags, struct pt_regs *regs,
149 			       int signr)
150 {
151 	bust_spinlocks(0);
152 	die_owner = -1;
153 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
154 	die_nest_count--;
155 	oops_exit();
156 	printk("\n");
157 	if (!die_nest_count)
158 		/* Nest count reaches zero, release the lock. */
159 		arch_spin_unlock(&die_lock);
160 	raw_local_irq_restore(flags);
161 
162 	crash_fadump(regs, "die oops");
163 
164 	/*
165 	 * A system reset (0x100) is a request to dump, so we always send
166 	 * it through the crashdump code.
167 	 */
168 	if (kexec_should_crash(current) || (TRAP(regs) == 0x100)) {
169 		crash_kexec(regs);
170 
171 		/*
172 		 * We aren't the primary crash CPU. We need to send it
173 		 * to a holding pattern to avoid it ending up in the panic
174 		 * code.
175 		 */
176 		crash_kexec_secondary(regs);
177 	}
178 
179 	if (!signr)
180 		return;
181 
182 	/*
183 	 * While our oops output is serialised by a spinlock, output
184 	 * from panic() called below can race and corrupt it. If we
185 	 * know we are going to panic, delay for 1 second so we have a
186 	 * chance to get clean backtraces from all CPUs that are oopsing.
187 	 */
188 	if (in_interrupt() || panic_on_oops || !current->pid ||
189 	    is_global_init(current)) {
190 		mdelay(MSEC_PER_SEC);
191 	}
192 
193 	if (in_interrupt())
194 		panic("Fatal exception in interrupt");
195 	if (panic_on_oops)
196 		panic("Fatal exception");
197 	do_exit(signr);
198 }
199 
200 static int __kprobes __die(const char *str, struct pt_regs *regs, long err)
201 {
202 	printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
203 #ifdef CONFIG_PREEMPT
204 	printk("PREEMPT ");
205 #endif
206 #ifdef CONFIG_SMP
207 	printk("SMP NR_CPUS=%d ", NR_CPUS);
208 #endif
209 	if (debug_pagealloc_enabled())
210 		printk("DEBUG_PAGEALLOC ");
211 #ifdef CONFIG_NUMA
212 	printk("NUMA ");
213 #endif
214 	printk("%s\n", ppc_md.name ? ppc_md.name : "");
215 
216 	if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV) == NOTIFY_STOP)
217 		return 1;
218 
219 	print_modules();
220 	show_regs(regs);
221 
222 	return 0;
223 }
224 
225 void die(const char *str, struct pt_regs *regs, long err)
226 {
227 	unsigned long flags = oops_begin(regs);
228 
229 	if (__die(str, regs, err))
230 		err = 0;
231 	oops_end(flags, regs, err);
232 }
233 
234 void user_single_step_siginfo(struct task_struct *tsk,
235 				struct pt_regs *regs, siginfo_t *info)
236 {
237 	memset(info, 0, sizeof(*info));
238 	info->si_signo = SIGTRAP;
239 	info->si_code = TRAP_TRACE;
240 	info->si_addr = (void __user *)regs->nip;
241 }
242 
243 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
244 {
245 	siginfo_t info;
246 	const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
247 			"at %08lx nip %08lx lr %08lx code %x\n";
248 	const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
249 			"at %016lx nip %016lx lr %016lx code %x\n";
250 
251 	if (!user_mode(regs)) {
252 		die("Exception in kernel mode", regs, signr);
253 		return;
254 	}
255 
256 	if (show_unhandled_signals && unhandled_signal(current, signr)) {
257 		printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
258 				   current->comm, current->pid, signr,
259 				   addr, regs->nip, regs->link, code);
260 	}
261 
262 	if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
263 		local_irq_enable();
264 
265 	current->thread.trap_nr = code;
266 	memset(&info, 0, sizeof(info));
267 	info.si_signo = signr;
268 	info.si_code = code;
269 	info.si_addr = (void __user *) addr;
270 	force_sig_info(signr, &info, current);
271 }
272 
273 #ifdef CONFIG_PPC64
274 void system_reset_exception(struct pt_regs *regs)
275 {
276 	/* See if any machine dependent calls */
277 	if (ppc_md.system_reset_exception) {
278 		if (ppc_md.system_reset_exception(regs))
279 			return;
280 	}
281 
282 	die("System Reset", regs, SIGABRT);
283 
284 	/* Must die if the interrupt is not recoverable */
285 	if (!(regs->msr & MSR_RI))
286 		panic("Unrecoverable System Reset");
287 
288 	/* What should we do here? We could issue a shutdown or hard reset. */
289 }
290 
291 /*
292  * This function is called in real mode. Strictly no printk's please.
293  *
294  * regs->nip and regs->msr contains srr0 and ssr1.
295  */
296 long machine_check_early(struct pt_regs *regs)
297 {
298 	long handled = 0;
299 
300 	__this_cpu_inc(irq_stat.mce_exceptions);
301 
302 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
303 
304 	if (cur_cpu_spec && cur_cpu_spec->machine_check_early)
305 		handled = cur_cpu_spec->machine_check_early(regs);
306 	return handled;
307 }
308 
309 long hmi_exception_realmode(struct pt_regs *regs)
310 {
311 	__this_cpu_inc(irq_stat.hmi_exceptions);
312 
313 	wait_for_subcore_guest_exit();
314 
315 	if (ppc_md.hmi_exception_early)
316 		ppc_md.hmi_exception_early(regs);
317 
318 	wait_for_tb_resync();
319 
320 	return 0;
321 }
322 
323 #endif
324 
325 /*
326  * I/O accesses can cause machine checks on powermacs.
327  * Check if the NIP corresponds to the address of a sync
328  * instruction for which there is an entry in the exception
329  * table.
330  * Note that the 601 only takes a machine check on TEA
331  * (transfer error ack) signal assertion, and does not
332  * set any of the top 16 bits of SRR1.
333  *  -- paulus.
334  */
335 static inline int check_io_access(struct pt_regs *regs)
336 {
337 #ifdef CONFIG_PPC32
338 	unsigned long msr = regs->msr;
339 	const struct exception_table_entry *entry;
340 	unsigned int *nip = (unsigned int *)regs->nip;
341 
342 	if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
343 	    && (entry = search_exception_tables(regs->nip)) != NULL) {
344 		/*
345 		 * Check that it's a sync instruction, or somewhere
346 		 * in the twi; isync; nop sequence that inb/inw/inl uses.
347 		 * As the address is in the exception table
348 		 * we should be able to read the instr there.
349 		 * For the debug message, we look at the preceding
350 		 * load or store.
351 		 */
352 		if (*nip == 0x60000000)		/* nop */
353 			nip -= 2;
354 		else if (*nip == 0x4c00012c)	/* isync */
355 			--nip;
356 		if (*nip == 0x7c0004ac || (*nip >> 26) == 3) {
357 			/* sync or twi */
358 			unsigned int rb;
359 
360 			--nip;
361 			rb = (*nip >> 11) & 0x1f;
362 			printk(KERN_DEBUG "%s bad port %lx at %p\n",
363 			       (*nip & 0x100)? "OUT to": "IN from",
364 			       regs->gpr[rb] - _IO_BASE, nip);
365 			regs->msr |= MSR_RI;
366 			regs->nip = entry->fixup;
367 			return 1;
368 		}
369 	}
370 #endif /* CONFIG_PPC32 */
371 	return 0;
372 }
373 
374 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
375 /* On 4xx, the reason for the machine check or program exception
376    is in the ESR. */
377 #define get_reason(regs)	((regs)->dsisr)
378 #ifndef CONFIG_FSL_BOOKE
379 #define get_mc_reason(regs)	((regs)->dsisr)
380 #else
381 #define get_mc_reason(regs)	(mfspr(SPRN_MCSR))
382 #endif
383 #define REASON_FP		ESR_FP
384 #define REASON_ILLEGAL		(ESR_PIL | ESR_PUO)
385 #define REASON_PRIVILEGED	ESR_PPR
386 #define REASON_TRAP		ESR_PTR
387 
388 /* single-step stuff */
389 #define single_stepping(regs)	(current->thread.debug.dbcr0 & DBCR0_IC)
390 #define clear_single_step(regs)	(current->thread.debug.dbcr0 &= ~DBCR0_IC)
391 
392 #else
393 /* On non-4xx, the reason for the machine check or program
394    exception is in the MSR. */
395 #define get_reason(regs)	((regs)->msr)
396 #define get_mc_reason(regs)	((regs)->msr)
397 #define REASON_TM		0x200000
398 #define REASON_FP		0x100000
399 #define REASON_ILLEGAL		0x80000
400 #define REASON_PRIVILEGED	0x40000
401 #define REASON_TRAP		0x20000
402 
403 #define single_stepping(regs)	((regs)->msr & MSR_SE)
404 #define clear_single_step(regs)	((regs)->msr &= ~MSR_SE)
405 #endif
406 
407 #if defined(CONFIG_4xx)
408 int machine_check_4xx(struct pt_regs *regs)
409 {
410 	unsigned long reason = get_mc_reason(regs);
411 
412 	if (reason & ESR_IMCP) {
413 		printk("Instruction");
414 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
415 	} else
416 		printk("Data");
417 	printk(" machine check in kernel mode.\n");
418 
419 	return 0;
420 }
421 
422 int machine_check_440A(struct pt_regs *regs)
423 {
424 	unsigned long reason = get_mc_reason(regs);
425 
426 	printk("Machine check in kernel mode.\n");
427 	if (reason & ESR_IMCP){
428 		printk("Instruction Synchronous Machine Check exception\n");
429 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
430 	}
431 	else {
432 		u32 mcsr = mfspr(SPRN_MCSR);
433 		if (mcsr & MCSR_IB)
434 			printk("Instruction Read PLB Error\n");
435 		if (mcsr & MCSR_DRB)
436 			printk("Data Read PLB Error\n");
437 		if (mcsr & MCSR_DWB)
438 			printk("Data Write PLB Error\n");
439 		if (mcsr & MCSR_TLBP)
440 			printk("TLB Parity Error\n");
441 		if (mcsr & MCSR_ICP){
442 			flush_instruction_cache();
443 			printk("I-Cache Parity Error\n");
444 		}
445 		if (mcsr & MCSR_DCSP)
446 			printk("D-Cache Search Parity Error\n");
447 		if (mcsr & MCSR_DCFP)
448 			printk("D-Cache Flush Parity Error\n");
449 		if (mcsr & MCSR_IMPE)
450 			printk("Machine Check exception is imprecise\n");
451 
452 		/* Clear MCSR */
453 		mtspr(SPRN_MCSR, mcsr);
454 	}
455 	return 0;
456 }
457 
458 int machine_check_47x(struct pt_regs *regs)
459 {
460 	unsigned long reason = get_mc_reason(regs);
461 	u32 mcsr;
462 
463 	printk(KERN_ERR "Machine check in kernel mode.\n");
464 	if (reason & ESR_IMCP) {
465 		printk(KERN_ERR
466 		       "Instruction Synchronous Machine Check exception\n");
467 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
468 		return 0;
469 	}
470 	mcsr = mfspr(SPRN_MCSR);
471 	if (mcsr & MCSR_IB)
472 		printk(KERN_ERR "Instruction Read PLB Error\n");
473 	if (mcsr & MCSR_DRB)
474 		printk(KERN_ERR "Data Read PLB Error\n");
475 	if (mcsr & MCSR_DWB)
476 		printk(KERN_ERR "Data Write PLB Error\n");
477 	if (mcsr & MCSR_TLBP)
478 		printk(KERN_ERR "TLB Parity Error\n");
479 	if (mcsr & MCSR_ICP) {
480 		flush_instruction_cache();
481 		printk(KERN_ERR "I-Cache Parity Error\n");
482 	}
483 	if (mcsr & MCSR_DCSP)
484 		printk(KERN_ERR "D-Cache Search Parity Error\n");
485 	if (mcsr & PPC47x_MCSR_GPR)
486 		printk(KERN_ERR "GPR Parity Error\n");
487 	if (mcsr & PPC47x_MCSR_FPR)
488 		printk(KERN_ERR "FPR Parity Error\n");
489 	if (mcsr & PPC47x_MCSR_IPR)
490 		printk(KERN_ERR "Machine Check exception is imprecise\n");
491 
492 	/* Clear MCSR */
493 	mtspr(SPRN_MCSR, mcsr);
494 
495 	return 0;
496 }
497 #elif defined(CONFIG_E500)
498 int machine_check_e500mc(struct pt_regs *regs)
499 {
500 	unsigned long mcsr = mfspr(SPRN_MCSR);
501 	unsigned long reason = mcsr;
502 	int recoverable = 1;
503 
504 	if (reason & MCSR_LD) {
505 		recoverable = fsl_rio_mcheck_exception(regs);
506 		if (recoverable == 1)
507 			goto silent_out;
508 	}
509 
510 	printk("Machine check in kernel mode.\n");
511 	printk("Caused by (from MCSR=%lx): ", reason);
512 
513 	if (reason & MCSR_MCP)
514 		printk("Machine Check Signal\n");
515 
516 	if (reason & MCSR_ICPERR) {
517 		printk("Instruction Cache Parity Error\n");
518 
519 		/*
520 		 * This is recoverable by invalidating the i-cache.
521 		 */
522 		mtspr(SPRN_L1CSR1, mfspr(SPRN_L1CSR1) | L1CSR1_ICFI);
523 		while (mfspr(SPRN_L1CSR1) & L1CSR1_ICFI)
524 			;
525 
526 		/*
527 		 * This will generally be accompanied by an instruction
528 		 * fetch error report -- only treat MCSR_IF as fatal
529 		 * if it wasn't due to an L1 parity error.
530 		 */
531 		reason &= ~MCSR_IF;
532 	}
533 
534 	if (reason & MCSR_DCPERR_MC) {
535 		printk("Data Cache Parity Error\n");
536 
537 		/*
538 		 * In write shadow mode we auto-recover from the error, but it
539 		 * may still get logged and cause a machine check.  We should
540 		 * only treat the non-write shadow case as non-recoverable.
541 		 */
542 		if (!(mfspr(SPRN_L1CSR2) & L1CSR2_DCWS))
543 			recoverable = 0;
544 	}
545 
546 	if (reason & MCSR_L2MMU_MHIT) {
547 		printk("Hit on multiple TLB entries\n");
548 		recoverable = 0;
549 	}
550 
551 	if (reason & MCSR_NMI)
552 		printk("Non-maskable interrupt\n");
553 
554 	if (reason & MCSR_IF) {
555 		printk("Instruction Fetch Error Report\n");
556 		recoverable = 0;
557 	}
558 
559 	if (reason & MCSR_LD) {
560 		printk("Load Error Report\n");
561 		recoverable = 0;
562 	}
563 
564 	if (reason & MCSR_ST) {
565 		printk("Store Error Report\n");
566 		recoverable = 0;
567 	}
568 
569 	if (reason & MCSR_LDG) {
570 		printk("Guarded Load Error Report\n");
571 		recoverable = 0;
572 	}
573 
574 	if (reason & MCSR_TLBSYNC)
575 		printk("Simultaneous tlbsync operations\n");
576 
577 	if (reason & MCSR_BSL2_ERR) {
578 		printk("Level 2 Cache Error\n");
579 		recoverable = 0;
580 	}
581 
582 	if (reason & MCSR_MAV) {
583 		u64 addr;
584 
585 		addr = mfspr(SPRN_MCAR);
586 		addr |= (u64)mfspr(SPRN_MCARU) << 32;
587 
588 		printk("Machine Check %s Address: %#llx\n",
589 		       reason & MCSR_MEA ? "Effective" : "Physical", addr);
590 	}
591 
592 silent_out:
593 	mtspr(SPRN_MCSR, mcsr);
594 	return mfspr(SPRN_MCSR) == 0 && recoverable;
595 }
596 
597 int machine_check_e500(struct pt_regs *regs)
598 {
599 	unsigned long reason = get_mc_reason(regs);
600 
601 	if (reason & MCSR_BUS_RBERR) {
602 		if (fsl_rio_mcheck_exception(regs))
603 			return 1;
604 		if (fsl_pci_mcheck_exception(regs))
605 			return 1;
606 	}
607 
608 	printk("Machine check in kernel mode.\n");
609 	printk("Caused by (from MCSR=%lx): ", reason);
610 
611 	if (reason & MCSR_MCP)
612 		printk("Machine Check Signal\n");
613 	if (reason & MCSR_ICPERR)
614 		printk("Instruction Cache Parity Error\n");
615 	if (reason & MCSR_DCP_PERR)
616 		printk("Data Cache Push Parity Error\n");
617 	if (reason & MCSR_DCPERR)
618 		printk("Data Cache Parity Error\n");
619 	if (reason & MCSR_BUS_IAERR)
620 		printk("Bus - Instruction Address Error\n");
621 	if (reason & MCSR_BUS_RAERR)
622 		printk("Bus - Read Address Error\n");
623 	if (reason & MCSR_BUS_WAERR)
624 		printk("Bus - Write Address Error\n");
625 	if (reason & MCSR_BUS_IBERR)
626 		printk("Bus - Instruction Data Error\n");
627 	if (reason & MCSR_BUS_RBERR)
628 		printk("Bus - Read Data Bus Error\n");
629 	if (reason & MCSR_BUS_WBERR)
630 		printk("Bus - Write Data Bus Error\n");
631 	if (reason & MCSR_BUS_IPERR)
632 		printk("Bus - Instruction Parity Error\n");
633 	if (reason & MCSR_BUS_RPERR)
634 		printk("Bus - Read Parity Error\n");
635 
636 	return 0;
637 }
638 
639 int machine_check_generic(struct pt_regs *regs)
640 {
641 	return 0;
642 }
643 #elif defined(CONFIG_E200)
644 int machine_check_e200(struct pt_regs *regs)
645 {
646 	unsigned long reason = get_mc_reason(regs);
647 
648 	printk("Machine check in kernel mode.\n");
649 	printk("Caused by (from MCSR=%lx): ", reason);
650 
651 	if (reason & MCSR_MCP)
652 		printk("Machine Check Signal\n");
653 	if (reason & MCSR_CP_PERR)
654 		printk("Cache Push Parity Error\n");
655 	if (reason & MCSR_CPERR)
656 		printk("Cache Parity Error\n");
657 	if (reason & MCSR_EXCP_ERR)
658 		printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
659 	if (reason & MCSR_BUS_IRERR)
660 		printk("Bus - Read Bus Error on instruction fetch\n");
661 	if (reason & MCSR_BUS_DRERR)
662 		printk("Bus - Read Bus Error on data load\n");
663 	if (reason & MCSR_BUS_WRERR)
664 		printk("Bus - Write Bus Error on buffered store or cache line push\n");
665 
666 	return 0;
667 }
668 #else
669 int machine_check_generic(struct pt_regs *regs)
670 {
671 	unsigned long reason = get_mc_reason(regs);
672 
673 	printk("Machine check in kernel mode.\n");
674 	printk("Caused by (from SRR1=%lx): ", reason);
675 	switch (reason & 0x601F0000) {
676 	case 0x80000:
677 		printk("Machine check signal\n");
678 		break;
679 	case 0:		/* for 601 */
680 	case 0x40000:
681 	case 0x140000:	/* 7450 MSS error and TEA */
682 		printk("Transfer error ack signal\n");
683 		break;
684 	case 0x20000:
685 		printk("Data parity error signal\n");
686 		break;
687 	case 0x10000:
688 		printk("Address parity error signal\n");
689 		break;
690 	case 0x20000000:
691 		printk("L1 Data Cache error\n");
692 		break;
693 	case 0x40000000:
694 		printk("L1 Instruction Cache error\n");
695 		break;
696 	case 0x00100000:
697 		printk("L2 data cache parity error\n");
698 		break;
699 	default:
700 		printk("Unknown values in msr\n");
701 	}
702 	return 0;
703 }
704 #endif /* everything else */
705 
706 void machine_check_exception(struct pt_regs *regs)
707 {
708 	enum ctx_state prev_state = exception_enter();
709 	int recover = 0;
710 
711 	__this_cpu_inc(irq_stat.mce_exceptions);
712 
713 	/* See if any machine dependent calls. In theory, we would want
714 	 * to call the CPU first, and call the ppc_md. one if the CPU
715 	 * one returns a positive number. However there is existing code
716 	 * that assumes the board gets a first chance, so let's keep it
717 	 * that way for now and fix things later. --BenH.
718 	 */
719 	if (ppc_md.machine_check_exception)
720 		recover = ppc_md.machine_check_exception(regs);
721 	else if (cur_cpu_spec->machine_check)
722 		recover = cur_cpu_spec->machine_check(regs);
723 
724 	if (recover > 0)
725 		goto bail;
726 
727 #if defined(CONFIG_8xx) && defined(CONFIG_PCI)
728 	/* the qspan pci read routines can cause machine checks -- Cort
729 	 *
730 	 * yuck !!! that totally needs to go away ! There are better ways
731 	 * to deal with that than having a wart in the mcheck handler.
732 	 * -- BenH
733 	 */
734 	bad_page_fault(regs, regs->dar, SIGBUS);
735 	goto bail;
736 #endif
737 
738 	if (debugger_fault_handler(regs))
739 		goto bail;
740 
741 	if (check_io_access(regs))
742 		goto bail;
743 
744 	die("Machine check", regs, SIGBUS);
745 
746 	/* Must die if the interrupt is not recoverable */
747 	if (!(regs->msr & MSR_RI))
748 		panic("Unrecoverable Machine check");
749 
750 bail:
751 	exception_exit(prev_state);
752 }
753 
754 void SMIException(struct pt_regs *regs)
755 {
756 	die("System Management Interrupt", regs, SIGABRT);
757 }
758 
759 void handle_hmi_exception(struct pt_regs *regs)
760 {
761 	struct pt_regs *old_regs;
762 
763 	old_regs = set_irq_regs(regs);
764 	irq_enter();
765 
766 	if (ppc_md.handle_hmi_exception)
767 		ppc_md.handle_hmi_exception(regs);
768 
769 	irq_exit();
770 	set_irq_regs(old_regs);
771 }
772 
773 void unknown_exception(struct pt_regs *regs)
774 {
775 	enum ctx_state prev_state = exception_enter();
776 
777 	printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
778 	       regs->nip, regs->msr, regs->trap);
779 
780 	_exception(SIGTRAP, regs, 0, 0);
781 
782 	exception_exit(prev_state);
783 }
784 
785 void instruction_breakpoint_exception(struct pt_regs *regs)
786 {
787 	enum ctx_state prev_state = exception_enter();
788 
789 	if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
790 					5, SIGTRAP) == NOTIFY_STOP)
791 		goto bail;
792 	if (debugger_iabr_match(regs))
793 		goto bail;
794 	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
795 
796 bail:
797 	exception_exit(prev_state);
798 }
799 
800 void RunModeException(struct pt_regs *regs)
801 {
802 	_exception(SIGTRAP, regs, 0, 0);
803 }
804 
805 void __kprobes single_step_exception(struct pt_regs *regs)
806 {
807 	enum ctx_state prev_state = exception_enter();
808 
809 	clear_single_step(regs);
810 
811 	if (notify_die(DIE_SSTEP, "single_step", regs, 5,
812 					5, SIGTRAP) == NOTIFY_STOP)
813 		goto bail;
814 	if (debugger_sstep(regs))
815 		goto bail;
816 
817 	_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
818 
819 bail:
820 	exception_exit(prev_state);
821 }
822 
823 /*
824  * After we have successfully emulated an instruction, we have to
825  * check if the instruction was being single-stepped, and if so,
826  * pretend we got a single-step exception.  This was pointed out
827  * by Kumar Gala.  -- paulus
828  */
829 static void emulate_single_step(struct pt_regs *regs)
830 {
831 	if (single_stepping(regs))
832 		single_step_exception(regs);
833 }
834 
835 static inline int __parse_fpscr(unsigned long fpscr)
836 {
837 	int ret = 0;
838 
839 	/* Invalid operation */
840 	if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
841 		ret = FPE_FLTINV;
842 
843 	/* Overflow */
844 	else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
845 		ret = FPE_FLTOVF;
846 
847 	/* Underflow */
848 	else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
849 		ret = FPE_FLTUND;
850 
851 	/* Divide by zero */
852 	else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
853 		ret = FPE_FLTDIV;
854 
855 	/* Inexact result */
856 	else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
857 		ret = FPE_FLTRES;
858 
859 	return ret;
860 }
861 
862 static void parse_fpe(struct pt_regs *regs)
863 {
864 	int code = 0;
865 
866 	flush_fp_to_thread(current);
867 
868 	code = __parse_fpscr(current->thread.fp_state.fpscr);
869 
870 	_exception(SIGFPE, regs, code, regs->nip);
871 }
872 
873 /*
874  * Illegal instruction emulation support.  Originally written to
875  * provide the PVR to user applications using the mfspr rd, PVR.
876  * Return non-zero if we can't emulate, or -EFAULT if the associated
877  * memory access caused an access fault.  Return zero on success.
878  *
879  * There are a couple of ways to do this, either "decode" the instruction
880  * or directly match lots of bits.  In this case, matching lots of
881  * bits is faster and easier.
882  *
883  */
884 static int emulate_string_inst(struct pt_regs *regs, u32 instword)
885 {
886 	u8 rT = (instword >> 21) & 0x1f;
887 	u8 rA = (instword >> 16) & 0x1f;
888 	u8 NB_RB = (instword >> 11) & 0x1f;
889 	u32 num_bytes;
890 	unsigned long EA;
891 	int pos = 0;
892 
893 	/* Early out if we are an invalid form of lswx */
894 	if ((instword & PPC_INST_STRING_MASK) == PPC_INST_LSWX)
895 		if ((rT == rA) || (rT == NB_RB))
896 			return -EINVAL;
897 
898 	EA = (rA == 0) ? 0 : regs->gpr[rA];
899 
900 	switch (instword & PPC_INST_STRING_MASK) {
901 		case PPC_INST_LSWX:
902 		case PPC_INST_STSWX:
903 			EA += NB_RB;
904 			num_bytes = regs->xer & 0x7f;
905 			break;
906 		case PPC_INST_LSWI:
907 		case PPC_INST_STSWI:
908 			num_bytes = (NB_RB == 0) ? 32 : NB_RB;
909 			break;
910 		default:
911 			return -EINVAL;
912 	}
913 
914 	while (num_bytes != 0)
915 	{
916 		u8 val;
917 		u32 shift = 8 * (3 - (pos & 0x3));
918 
919 		/* if process is 32-bit, clear upper 32 bits of EA */
920 		if ((regs->msr & MSR_64BIT) == 0)
921 			EA &= 0xFFFFFFFF;
922 
923 		switch ((instword & PPC_INST_STRING_MASK)) {
924 			case PPC_INST_LSWX:
925 			case PPC_INST_LSWI:
926 				if (get_user(val, (u8 __user *)EA))
927 					return -EFAULT;
928 				/* first time updating this reg,
929 				 * zero it out */
930 				if (pos == 0)
931 					regs->gpr[rT] = 0;
932 				regs->gpr[rT] |= val << shift;
933 				break;
934 			case PPC_INST_STSWI:
935 			case PPC_INST_STSWX:
936 				val = regs->gpr[rT] >> shift;
937 				if (put_user(val, (u8 __user *)EA))
938 					return -EFAULT;
939 				break;
940 		}
941 		/* move EA to next address */
942 		EA += 1;
943 		num_bytes--;
944 
945 		/* manage our position within the register */
946 		if (++pos == 4) {
947 			pos = 0;
948 			if (++rT == 32)
949 				rT = 0;
950 		}
951 	}
952 
953 	return 0;
954 }
955 
956 static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword)
957 {
958 	u32 ra,rs;
959 	unsigned long tmp;
960 
961 	ra = (instword >> 16) & 0x1f;
962 	rs = (instword >> 21) & 0x1f;
963 
964 	tmp = regs->gpr[rs];
965 	tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL);
966 	tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL);
967 	tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
968 	regs->gpr[ra] = tmp;
969 
970 	return 0;
971 }
972 
973 static int emulate_isel(struct pt_regs *regs, u32 instword)
974 {
975 	u8 rT = (instword >> 21) & 0x1f;
976 	u8 rA = (instword >> 16) & 0x1f;
977 	u8 rB = (instword >> 11) & 0x1f;
978 	u8 BC = (instword >> 6) & 0x1f;
979 	u8 bit;
980 	unsigned long tmp;
981 
982 	tmp = (rA == 0) ? 0 : regs->gpr[rA];
983 	bit = (regs->ccr >> (31 - BC)) & 0x1;
984 
985 	regs->gpr[rT] = bit ? tmp : regs->gpr[rB];
986 
987 	return 0;
988 }
989 
990 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
991 static inline bool tm_abort_check(struct pt_regs *regs, int cause)
992 {
993         /* If we're emulating a load/store in an active transaction, we cannot
994          * emulate it as the kernel operates in transaction suspended context.
995          * We need to abort the transaction.  This creates a persistent TM
996          * abort so tell the user what caused it with a new code.
997 	 */
998 	if (MSR_TM_TRANSACTIONAL(regs->msr)) {
999 		tm_enable();
1000 		tm_abort(cause);
1001 		return true;
1002 	}
1003 	return false;
1004 }
1005 #else
1006 static inline bool tm_abort_check(struct pt_regs *regs, int reason)
1007 {
1008 	return false;
1009 }
1010 #endif
1011 
1012 static int emulate_instruction(struct pt_regs *regs)
1013 {
1014 	u32 instword;
1015 	u32 rd;
1016 
1017 	if (!user_mode(regs))
1018 		return -EINVAL;
1019 	CHECK_FULL_REGS(regs);
1020 
1021 	if (get_user(instword, (u32 __user *)(regs->nip)))
1022 		return -EFAULT;
1023 
1024 	/* Emulate the mfspr rD, PVR. */
1025 	if ((instword & PPC_INST_MFSPR_PVR_MASK) == PPC_INST_MFSPR_PVR) {
1026 		PPC_WARN_EMULATED(mfpvr, regs);
1027 		rd = (instword >> 21) & 0x1f;
1028 		regs->gpr[rd] = mfspr(SPRN_PVR);
1029 		return 0;
1030 	}
1031 
1032 	/* Emulating the dcba insn is just a no-op.  */
1033 	if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA) {
1034 		PPC_WARN_EMULATED(dcba, regs);
1035 		return 0;
1036 	}
1037 
1038 	/* Emulate the mcrxr insn.  */
1039 	if ((instword & PPC_INST_MCRXR_MASK) == PPC_INST_MCRXR) {
1040 		int shift = (instword >> 21) & 0x1c;
1041 		unsigned long msk = 0xf0000000UL >> shift;
1042 
1043 		PPC_WARN_EMULATED(mcrxr, regs);
1044 		regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
1045 		regs->xer &= ~0xf0000000UL;
1046 		return 0;
1047 	}
1048 
1049 	/* Emulate load/store string insn. */
1050 	if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {
1051 		if (tm_abort_check(regs,
1052 				   TM_CAUSE_EMULATE | TM_CAUSE_PERSISTENT))
1053 			return -EINVAL;
1054 		PPC_WARN_EMULATED(string, regs);
1055 		return emulate_string_inst(regs, instword);
1056 	}
1057 
1058 	/* Emulate the popcntb (Population Count Bytes) instruction. */
1059 	if ((instword & PPC_INST_POPCNTB_MASK) == PPC_INST_POPCNTB) {
1060 		PPC_WARN_EMULATED(popcntb, regs);
1061 		return emulate_popcntb_inst(regs, instword);
1062 	}
1063 
1064 	/* Emulate isel (Integer Select) instruction */
1065 	if ((instword & PPC_INST_ISEL_MASK) == PPC_INST_ISEL) {
1066 		PPC_WARN_EMULATED(isel, regs);
1067 		return emulate_isel(regs, instword);
1068 	}
1069 
1070 	/* Emulate sync instruction variants */
1071 	if ((instword & PPC_INST_SYNC_MASK) == PPC_INST_SYNC) {
1072 		PPC_WARN_EMULATED(sync, regs);
1073 		asm volatile("sync");
1074 		return 0;
1075 	}
1076 
1077 #ifdef CONFIG_PPC64
1078 	/* Emulate the mfspr rD, DSCR. */
1079 	if ((((instword & PPC_INST_MFSPR_DSCR_USER_MASK) ==
1080 		PPC_INST_MFSPR_DSCR_USER) ||
1081 	     ((instword & PPC_INST_MFSPR_DSCR_MASK) ==
1082 		PPC_INST_MFSPR_DSCR)) &&
1083 			cpu_has_feature(CPU_FTR_DSCR)) {
1084 		PPC_WARN_EMULATED(mfdscr, regs);
1085 		rd = (instword >> 21) & 0x1f;
1086 		regs->gpr[rd] = mfspr(SPRN_DSCR);
1087 		return 0;
1088 	}
1089 	/* Emulate the mtspr DSCR, rD. */
1090 	if ((((instword & PPC_INST_MTSPR_DSCR_USER_MASK) ==
1091 		PPC_INST_MTSPR_DSCR_USER) ||
1092 	     ((instword & PPC_INST_MTSPR_DSCR_MASK) ==
1093 		PPC_INST_MTSPR_DSCR)) &&
1094 			cpu_has_feature(CPU_FTR_DSCR)) {
1095 		PPC_WARN_EMULATED(mtdscr, regs);
1096 		rd = (instword >> 21) & 0x1f;
1097 		current->thread.dscr = regs->gpr[rd];
1098 		current->thread.dscr_inherit = 1;
1099 		mtspr(SPRN_DSCR, current->thread.dscr);
1100 		return 0;
1101 	}
1102 #endif
1103 
1104 	return -EINVAL;
1105 }
1106 
1107 int is_valid_bugaddr(unsigned long addr)
1108 {
1109 	return is_kernel_addr(addr);
1110 }
1111 
1112 #ifdef CONFIG_MATH_EMULATION
1113 static int emulate_math(struct pt_regs *regs)
1114 {
1115 	int ret;
1116 	extern int do_mathemu(struct pt_regs *regs);
1117 
1118 	ret = do_mathemu(regs);
1119 	if (ret >= 0)
1120 		PPC_WARN_EMULATED(math, regs);
1121 
1122 	switch (ret) {
1123 	case 0:
1124 		emulate_single_step(regs);
1125 		return 0;
1126 	case 1: {
1127 			int code = 0;
1128 			code = __parse_fpscr(current->thread.fp_state.fpscr);
1129 			_exception(SIGFPE, regs, code, regs->nip);
1130 			return 0;
1131 		}
1132 	case -EFAULT:
1133 		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1134 		return 0;
1135 	}
1136 
1137 	return -1;
1138 }
1139 #else
1140 static inline int emulate_math(struct pt_regs *regs) { return -1; }
1141 #endif
1142 
1143 void __kprobes program_check_exception(struct pt_regs *regs)
1144 {
1145 	enum ctx_state prev_state = exception_enter();
1146 	unsigned int reason = get_reason(regs);
1147 
1148 	/* We can now get here via a FP Unavailable exception if the core
1149 	 * has no FPU, in that case the reason flags will be 0 */
1150 
1151 	if (reason & REASON_FP) {
1152 		/* IEEE FP exception */
1153 		parse_fpe(regs);
1154 		goto bail;
1155 	}
1156 	if (reason & REASON_TRAP) {
1157 		unsigned long bugaddr;
1158 		/* Debugger is first in line to stop recursive faults in
1159 		 * rcu_lock, notify_die, or atomic_notifier_call_chain */
1160 		if (debugger_bpt(regs))
1161 			goto bail;
1162 
1163 		/* trap exception */
1164 		if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
1165 				== NOTIFY_STOP)
1166 			goto bail;
1167 
1168 		bugaddr = regs->nip;
1169 		/*
1170 		 * Fixup bugaddr for BUG_ON() in real mode
1171 		 */
1172 		if (!is_kernel_addr(bugaddr) && !(regs->msr & MSR_IR))
1173 			bugaddr += PAGE_OFFSET;
1174 
1175 		if (!(regs->msr & MSR_PR) &&  /* not user-mode */
1176 		    report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {
1177 			regs->nip += 4;
1178 			goto bail;
1179 		}
1180 		_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
1181 		goto bail;
1182 	}
1183 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1184 	if (reason & REASON_TM) {
1185 		/* This is a TM "Bad Thing Exception" program check.
1186 		 * This occurs when:
1187 		 * -  An rfid/hrfid/mtmsrd attempts to cause an illegal
1188 		 *    transition in TM states.
1189 		 * -  A trechkpt is attempted when transactional.
1190 		 * -  A treclaim is attempted when non transactional.
1191 		 * -  A tend is illegally attempted.
1192 		 * -  writing a TM SPR when transactional.
1193 		 */
1194 		if (!user_mode(regs) &&
1195 		    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
1196 			regs->nip += 4;
1197 			goto bail;
1198 		}
1199 		/* If usermode caused this, it's done something illegal and
1200 		 * gets a SIGILL slap on the wrist.  We call it an illegal
1201 		 * operand to distinguish from the instruction just being bad
1202 		 * (e.g. executing a 'tend' on a CPU without TM!); it's an
1203 		 * illegal /placement/ of a valid instruction.
1204 		 */
1205 		if (user_mode(regs)) {
1206 			_exception(SIGILL, regs, ILL_ILLOPN, regs->nip);
1207 			goto bail;
1208 		} else {
1209 			printk(KERN_EMERG "Unexpected TM Bad Thing exception "
1210 			       "at %lx (msr 0x%x)\n", regs->nip, reason);
1211 			die("Unrecoverable exception", regs, SIGABRT);
1212 		}
1213 	}
1214 #endif
1215 
1216 	/*
1217 	 * If we took the program check in the kernel skip down to sending a
1218 	 * SIGILL. The subsequent cases all relate to emulating instructions
1219 	 * which we should only do for userspace. We also do not want to enable
1220 	 * interrupts for kernel faults because that might lead to further
1221 	 * faults, and loose the context of the original exception.
1222 	 */
1223 	if (!user_mode(regs))
1224 		goto sigill;
1225 
1226 	/* We restore the interrupt state now */
1227 	if (!arch_irq_disabled_regs(regs))
1228 		local_irq_enable();
1229 
1230 	/* (reason & REASON_ILLEGAL) would be the obvious thing here,
1231 	 * but there seems to be a hardware bug on the 405GP (RevD)
1232 	 * that means ESR is sometimes set incorrectly - either to
1233 	 * ESR_DST (!?) or 0.  In the process of chasing this with the
1234 	 * hardware people - not sure if it can happen on any illegal
1235 	 * instruction or only on FP instructions, whether there is a
1236 	 * pattern to occurrences etc. -dgibson 31/Mar/2003
1237 	 */
1238 	if (!emulate_math(regs))
1239 		goto bail;
1240 
1241 	/* Try to emulate it if we should. */
1242 	if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
1243 		switch (emulate_instruction(regs)) {
1244 		case 0:
1245 			regs->nip += 4;
1246 			emulate_single_step(regs);
1247 			goto bail;
1248 		case -EFAULT:
1249 			_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1250 			goto bail;
1251 		}
1252 	}
1253 
1254 sigill:
1255 	if (reason & REASON_PRIVILEGED)
1256 		_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1257 	else
1258 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1259 
1260 bail:
1261 	exception_exit(prev_state);
1262 }
1263 
1264 /*
1265  * This occurs when running in hypervisor mode on POWER6 or later
1266  * and an illegal instruction is encountered.
1267  */
1268 void __kprobes emulation_assist_interrupt(struct pt_regs *regs)
1269 {
1270 	regs->msr |= REASON_ILLEGAL;
1271 	program_check_exception(regs);
1272 }
1273 
1274 void alignment_exception(struct pt_regs *regs)
1275 {
1276 	enum ctx_state prev_state = exception_enter();
1277 	int sig, code, fixed = 0;
1278 
1279 	/* We restore the interrupt state now */
1280 	if (!arch_irq_disabled_regs(regs))
1281 		local_irq_enable();
1282 
1283 	if (tm_abort_check(regs, TM_CAUSE_ALIGNMENT | TM_CAUSE_PERSISTENT))
1284 		goto bail;
1285 
1286 	/* we don't implement logging of alignment exceptions */
1287 	if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
1288 		fixed = fix_alignment(regs);
1289 
1290 	if (fixed == 1) {
1291 		regs->nip += 4;	/* skip over emulated instruction */
1292 		emulate_single_step(regs);
1293 		goto bail;
1294 	}
1295 
1296 	/* Operand address was bad */
1297 	if (fixed == -EFAULT) {
1298 		sig = SIGSEGV;
1299 		code = SEGV_ACCERR;
1300 	} else {
1301 		sig = SIGBUS;
1302 		code = BUS_ADRALN;
1303 	}
1304 	if (user_mode(regs))
1305 		_exception(sig, regs, code, regs->dar);
1306 	else
1307 		bad_page_fault(regs, regs->dar, sig);
1308 
1309 bail:
1310 	exception_exit(prev_state);
1311 }
1312 
1313 void StackOverflow(struct pt_regs *regs)
1314 {
1315 	printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
1316 	       current, regs->gpr[1]);
1317 	debugger(regs);
1318 	show_regs(regs);
1319 	panic("kernel stack overflow");
1320 }
1321 
1322 void nonrecoverable_exception(struct pt_regs *regs)
1323 {
1324 	printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
1325 	       regs->nip, regs->msr);
1326 	debugger(regs);
1327 	die("nonrecoverable exception", regs, SIGKILL);
1328 }
1329 
1330 void kernel_fp_unavailable_exception(struct pt_regs *regs)
1331 {
1332 	enum ctx_state prev_state = exception_enter();
1333 
1334 	printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
1335 			  "%lx at %lx\n", regs->trap, regs->nip);
1336 	die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
1337 
1338 	exception_exit(prev_state);
1339 }
1340 
1341 void altivec_unavailable_exception(struct pt_regs *regs)
1342 {
1343 	enum ctx_state prev_state = exception_enter();
1344 
1345 	if (user_mode(regs)) {
1346 		/* A user program has executed an altivec instruction,
1347 		   but this kernel doesn't support altivec. */
1348 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1349 		goto bail;
1350 	}
1351 
1352 	printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
1353 			"%lx at %lx\n", regs->trap, regs->nip);
1354 	die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
1355 
1356 bail:
1357 	exception_exit(prev_state);
1358 }
1359 
1360 void vsx_unavailable_exception(struct pt_regs *regs)
1361 {
1362 	if (user_mode(regs)) {
1363 		/* A user program has executed an vsx instruction,
1364 		   but this kernel doesn't support vsx. */
1365 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1366 		return;
1367 	}
1368 
1369 	printk(KERN_EMERG "Unrecoverable VSX Unavailable Exception "
1370 			"%lx at %lx\n", regs->trap, regs->nip);
1371 	die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
1372 }
1373 
1374 #ifdef CONFIG_PPC64
1375 void facility_unavailable_exception(struct pt_regs *regs)
1376 {
1377 	static char *facility_strings[] = {
1378 		[FSCR_FP_LG] = "FPU",
1379 		[FSCR_VECVSX_LG] = "VMX/VSX",
1380 		[FSCR_DSCR_LG] = "DSCR",
1381 		[FSCR_PM_LG] = "PMU SPRs",
1382 		[FSCR_BHRB_LG] = "BHRB",
1383 		[FSCR_TM_LG] = "TM",
1384 		[FSCR_EBB_LG] = "EBB",
1385 		[FSCR_TAR_LG] = "TAR",
1386 		[FSCR_LM_LG] = "LM",
1387 	};
1388 	char *facility = "unknown";
1389 	u64 value;
1390 	u32 instword, rd;
1391 	u8 status;
1392 	bool hv;
1393 
1394 	hv = (regs->trap == 0xf80);
1395 	if (hv)
1396 		value = mfspr(SPRN_HFSCR);
1397 	else
1398 		value = mfspr(SPRN_FSCR);
1399 
1400 	status = value >> 56;
1401 	if (status == FSCR_DSCR_LG) {
1402 		/*
1403 		 * User is accessing the DSCR register using the problem
1404 		 * state only SPR number (0x03) either through a mfspr or
1405 		 * a mtspr instruction. If it is a write attempt through
1406 		 * a mtspr, then we set the inherit bit. This also allows
1407 		 * the user to write or read the register directly in the
1408 		 * future by setting via the FSCR DSCR bit. But in case it
1409 		 * is a read DSCR attempt through a mfspr instruction, we
1410 		 * just emulate the instruction instead. This code path will
1411 		 * always emulate all the mfspr instructions till the user
1412 		 * has attempted at least one mtspr instruction. This way it
1413 		 * preserves the same behaviour when the user is accessing
1414 		 * the DSCR through privilege level only SPR number (0x11)
1415 		 * which is emulated through illegal instruction exception.
1416 		 * We always leave HFSCR DSCR set.
1417 		 */
1418 		if (get_user(instword, (u32 __user *)(regs->nip))) {
1419 			pr_err("Failed to fetch the user instruction\n");
1420 			return;
1421 		}
1422 
1423 		/* Write into DSCR (mtspr 0x03, RS) */
1424 		if ((instword & PPC_INST_MTSPR_DSCR_USER_MASK)
1425 				== PPC_INST_MTSPR_DSCR_USER) {
1426 			rd = (instword >> 21) & 0x1f;
1427 			current->thread.dscr = regs->gpr[rd];
1428 			current->thread.dscr_inherit = 1;
1429 			current->thread.fscr |= FSCR_DSCR;
1430 			mtspr(SPRN_FSCR, current->thread.fscr);
1431 		}
1432 
1433 		/* Read from DSCR (mfspr RT, 0x03) */
1434 		if ((instword & PPC_INST_MFSPR_DSCR_USER_MASK)
1435 				== PPC_INST_MFSPR_DSCR_USER) {
1436 			if (emulate_instruction(regs)) {
1437 				pr_err("DSCR based mfspr emulation failed\n");
1438 				return;
1439 			}
1440 			regs->nip += 4;
1441 			emulate_single_step(regs);
1442 		}
1443 		return;
1444 	} else if ((status == FSCR_LM_LG) && cpu_has_feature(CPU_FTR_ARCH_300)) {
1445 		/*
1446 		 * This process has touched LM, so turn it on forever
1447 		 * for this process
1448 		 */
1449 		current->thread.fscr |= FSCR_LM;
1450 		mtspr(SPRN_FSCR, current->thread.fscr);
1451 		return;
1452 	}
1453 
1454 	if ((status < ARRAY_SIZE(facility_strings)) &&
1455 	    facility_strings[status])
1456 		facility = facility_strings[status];
1457 
1458 	/* We restore the interrupt state now */
1459 	if (!arch_irq_disabled_regs(regs))
1460 		local_irq_enable();
1461 
1462 	pr_err_ratelimited(
1463 		"%sFacility '%s' unavailable, exception at 0x%lx, MSR=%lx\n",
1464 		hv ? "Hypervisor " : "", facility, regs->nip, regs->msr);
1465 
1466 	if (user_mode(regs)) {
1467 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1468 		return;
1469 	}
1470 
1471 	die("Unexpected facility unavailable exception", regs, SIGABRT);
1472 }
1473 #endif
1474 
1475 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1476 
1477 void fp_unavailable_tm(struct pt_regs *regs)
1478 {
1479 	/* Note:  This does not handle any kind of FP laziness. */
1480 
1481 	TM_DEBUG("FP Unavailable trap whilst transactional at 0x%lx, MSR=%lx\n",
1482 		 regs->nip, regs->msr);
1483 
1484         /* We can only have got here if the task started using FP after
1485          * beginning the transaction.  So, the transactional regs are just a
1486          * copy of the checkpointed ones.  But, we still need to recheckpoint
1487          * as we're enabling FP for the process; it will return, abort the
1488          * transaction, and probably retry but now with FP enabled.  So the
1489          * checkpointed FP registers need to be loaded.
1490 	 */
1491 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
1492 	/* Reclaim didn't save out any FPRs to transact_fprs. */
1493 
1494 	/* Enable FP for the task: */
1495 	regs->msr |= (MSR_FP | current->thread.fpexc_mode);
1496 
1497 	/* This loads and recheckpoints the FP registers from
1498 	 * thread.fpr[].  They will remain in registers after the
1499 	 * checkpoint so we don't need to reload them after.
1500 	 * If VMX is in use, the VRs now hold checkpointed values,
1501 	 * so we don't want to load the VRs from the thread_struct.
1502 	 */
1503 	tm_recheckpoint(&current->thread, MSR_FP);
1504 
1505 	/* If VMX is in use, get the transactional values back */
1506 	if (regs->msr & MSR_VEC) {
1507 		do_load_up_transact_altivec(&current->thread);
1508 		/* At this point all the VSX state is loaded, so enable it */
1509 		regs->msr |= MSR_VSX;
1510 	}
1511 }
1512 
1513 void altivec_unavailable_tm(struct pt_regs *regs)
1514 {
1515 	/* See the comments in fp_unavailable_tm().  This function operates
1516 	 * the same way.
1517 	 */
1518 
1519 	TM_DEBUG("Vector Unavailable trap whilst transactional at 0x%lx,"
1520 		 "MSR=%lx\n",
1521 		 regs->nip, regs->msr);
1522 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
1523 	regs->msr |= MSR_VEC;
1524 	tm_recheckpoint(&current->thread, MSR_VEC);
1525 	current->thread.used_vr = 1;
1526 
1527 	if (regs->msr & MSR_FP) {
1528 		do_load_up_transact_fpu(&current->thread);
1529 		regs->msr |= MSR_VSX;
1530 	}
1531 }
1532 
1533 void vsx_unavailable_tm(struct pt_regs *regs)
1534 {
1535 	unsigned long orig_msr = regs->msr;
1536 
1537 	/* See the comments in fp_unavailable_tm().  This works similarly,
1538 	 * though we're loading both FP and VEC registers in here.
1539 	 *
1540 	 * If FP isn't in use, load FP regs.  If VEC isn't in use, load VEC
1541 	 * regs.  Either way, set MSR_VSX.
1542 	 */
1543 
1544 	TM_DEBUG("VSX Unavailable trap whilst transactional at 0x%lx,"
1545 		 "MSR=%lx\n",
1546 		 regs->nip, regs->msr);
1547 
1548 	current->thread.used_vsr = 1;
1549 
1550 	/* If FP and VMX are already loaded, we have all the state we need */
1551 	if ((orig_msr & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC)) {
1552 		regs->msr |= MSR_VSX;
1553 		return;
1554 	}
1555 
1556 	/* This reclaims FP and/or VR regs if they're already enabled */
1557 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
1558 
1559 	regs->msr |= MSR_VEC | MSR_FP | current->thread.fpexc_mode |
1560 		MSR_VSX;
1561 
1562 	/* This loads & recheckpoints FP and VRs; but we have
1563 	 * to be sure not to overwrite previously-valid state.
1564 	 */
1565 	tm_recheckpoint(&current->thread, regs->msr & ~orig_msr);
1566 
1567 	if (orig_msr & MSR_FP)
1568 		do_load_up_transact_fpu(&current->thread);
1569 	if (orig_msr & MSR_VEC)
1570 		do_load_up_transact_altivec(&current->thread);
1571 }
1572 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
1573 
1574 void performance_monitor_exception(struct pt_regs *regs)
1575 {
1576 	__this_cpu_inc(irq_stat.pmu_irqs);
1577 
1578 	perf_irq(regs);
1579 }
1580 
1581 #ifdef CONFIG_8xx
1582 void SoftwareEmulation(struct pt_regs *regs)
1583 {
1584 	CHECK_FULL_REGS(regs);
1585 
1586 	if (!user_mode(regs)) {
1587 		debugger(regs);
1588 		die("Kernel Mode Unimplemented Instruction or SW FPU Emulation",
1589 			regs, SIGFPE);
1590 	}
1591 
1592 	if (!emulate_math(regs))
1593 		return;
1594 
1595 	_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1596 }
1597 #endif /* CONFIG_8xx */
1598 
1599 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1600 static void handle_debug(struct pt_regs *regs, unsigned long debug_status)
1601 {
1602 	int changed = 0;
1603 	/*
1604 	 * Determine the cause of the debug event, clear the
1605 	 * event flags and send a trap to the handler. Torez
1606 	 */
1607 	if (debug_status & (DBSR_DAC1R | DBSR_DAC1W)) {
1608 		dbcr_dac(current) &= ~(DBCR_DAC1R | DBCR_DAC1W);
1609 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
1610 		current->thread.debug.dbcr2 &= ~DBCR2_DAC12MODE;
1611 #endif
1612 		do_send_trap(regs, mfspr(SPRN_DAC1), debug_status, TRAP_HWBKPT,
1613 			     5);
1614 		changed |= 0x01;
1615 	}  else if (debug_status & (DBSR_DAC2R | DBSR_DAC2W)) {
1616 		dbcr_dac(current) &= ~(DBCR_DAC2R | DBCR_DAC2W);
1617 		do_send_trap(regs, mfspr(SPRN_DAC2), debug_status, TRAP_HWBKPT,
1618 			     6);
1619 		changed |= 0x01;
1620 	}  else if (debug_status & DBSR_IAC1) {
1621 		current->thread.debug.dbcr0 &= ~DBCR0_IAC1;
1622 		dbcr_iac_range(current) &= ~DBCR_IAC12MODE;
1623 		do_send_trap(regs, mfspr(SPRN_IAC1), debug_status, TRAP_HWBKPT,
1624 			     1);
1625 		changed |= 0x01;
1626 	}  else if (debug_status & DBSR_IAC2) {
1627 		current->thread.debug.dbcr0 &= ~DBCR0_IAC2;
1628 		do_send_trap(regs, mfspr(SPRN_IAC2), debug_status, TRAP_HWBKPT,
1629 			     2);
1630 		changed |= 0x01;
1631 	}  else if (debug_status & DBSR_IAC3) {
1632 		current->thread.debug.dbcr0 &= ~DBCR0_IAC3;
1633 		dbcr_iac_range(current) &= ~DBCR_IAC34MODE;
1634 		do_send_trap(regs, mfspr(SPRN_IAC3), debug_status, TRAP_HWBKPT,
1635 			     3);
1636 		changed |= 0x01;
1637 	}  else if (debug_status & DBSR_IAC4) {
1638 		current->thread.debug.dbcr0 &= ~DBCR0_IAC4;
1639 		do_send_trap(regs, mfspr(SPRN_IAC4), debug_status, TRAP_HWBKPT,
1640 			     4);
1641 		changed |= 0x01;
1642 	}
1643 	/*
1644 	 * At the point this routine was called, the MSR(DE) was turned off.
1645 	 * Check all other debug flags and see if that bit needs to be turned
1646 	 * back on or not.
1647 	 */
1648 	if (DBCR_ACTIVE_EVENTS(current->thread.debug.dbcr0,
1649 			       current->thread.debug.dbcr1))
1650 		regs->msr |= MSR_DE;
1651 	else
1652 		/* Make sure the IDM flag is off */
1653 		current->thread.debug.dbcr0 &= ~DBCR0_IDM;
1654 
1655 	if (changed & 0x01)
1656 		mtspr(SPRN_DBCR0, current->thread.debug.dbcr0);
1657 }
1658 
1659 void __kprobes DebugException(struct pt_regs *regs, unsigned long debug_status)
1660 {
1661 	current->thread.debug.dbsr = debug_status;
1662 
1663 	/* Hack alert: On BookE, Branch Taken stops on the branch itself, while
1664 	 * on server, it stops on the target of the branch. In order to simulate
1665 	 * the server behaviour, we thus restart right away with a single step
1666 	 * instead of stopping here when hitting a BT
1667 	 */
1668 	if (debug_status & DBSR_BT) {
1669 		regs->msr &= ~MSR_DE;
1670 
1671 		/* Disable BT */
1672 		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_BT);
1673 		/* Clear the BT event */
1674 		mtspr(SPRN_DBSR, DBSR_BT);
1675 
1676 		/* Do the single step trick only when coming from userspace */
1677 		if (user_mode(regs)) {
1678 			current->thread.debug.dbcr0 &= ~DBCR0_BT;
1679 			current->thread.debug.dbcr0 |= DBCR0_IDM | DBCR0_IC;
1680 			regs->msr |= MSR_DE;
1681 			return;
1682 		}
1683 
1684 		if (notify_die(DIE_SSTEP, "block_step", regs, 5,
1685 			       5, SIGTRAP) == NOTIFY_STOP) {
1686 			return;
1687 		}
1688 		if (debugger_sstep(regs))
1689 			return;
1690 	} else if (debug_status & DBSR_IC) { 	/* Instruction complete */
1691 		regs->msr &= ~MSR_DE;
1692 
1693 		/* Disable instruction completion */
1694 		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
1695 		/* Clear the instruction completion event */
1696 		mtspr(SPRN_DBSR, DBSR_IC);
1697 
1698 		if (notify_die(DIE_SSTEP, "single_step", regs, 5,
1699 			       5, SIGTRAP) == NOTIFY_STOP) {
1700 			return;
1701 		}
1702 
1703 		if (debugger_sstep(regs))
1704 			return;
1705 
1706 		if (user_mode(regs)) {
1707 			current->thread.debug.dbcr0 &= ~DBCR0_IC;
1708 			if (DBCR_ACTIVE_EVENTS(current->thread.debug.dbcr0,
1709 					       current->thread.debug.dbcr1))
1710 				regs->msr |= MSR_DE;
1711 			else
1712 				/* Make sure the IDM bit is off */
1713 				current->thread.debug.dbcr0 &= ~DBCR0_IDM;
1714 		}
1715 
1716 		_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
1717 	} else
1718 		handle_debug(regs, debug_status);
1719 }
1720 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
1721 
1722 #if !defined(CONFIG_TAU_INT)
1723 void TAUException(struct pt_regs *regs)
1724 {
1725 	printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
1726 	       regs->nip, regs->msr, regs->trap, print_tainted());
1727 }
1728 #endif /* CONFIG_INT_TAU */
1729 
1730 #ifdef CONFIG_ALTIVEC
1731 void altivec_assist_exception(struct pt_regs *regs)
1732 {
1733 	int err;
1734 
1735 	if (!user_mode(regs)) {
1736 		printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
1737 		       " at %lx\n", regs->nip);
1738 		die("Kernel VMX/Altivec assist exception", regs, SIGILL);
1739 	}
1740 
1741 	flush_altivec_to_thread(current);
1742 
1743 	PPC_WARN_EMULATED(altivec, regs);
1744 	err = emulate_altivec(regs);
1745 	if (err == 0) {
1746 		regs->nip += 4;		/* skip emulated instruction */
1747 		emulate_single_step(regs);
1748 		return;
1749 	}
1750 
1751 	if (err == -EFAULT) {
1752 		/* got an error reading the instruction */
1753 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1754 	} else {
1755 		/* didn't recognize the instruction */
1756 		/* XXX quick hack for now: set the non-Java bit in the VSCR */
1757 		printk_ratelimited(KERN_ERR "Unrecognized altivec instruction "
1758 				   "in %s at %lx\n", current->comm, regs->nip);
1759 		current->thread.vr_state.vscr.u[3] |= 0x10000;
1760 	}
1761 }
1762 #endif /* CONFIG_ALTIVEC */
1763 
1764 #ifdef CONFIG_FSL_BOOKE
1765 void CacheLockingException(struct pt_regs *regs, unsigned long address,
1766 			   unsigned long error_code)
1767 {
1768 	/* We treat cache locking instructions from the user
1769 	 * as priv ops, in the future we could try to do
1770 	 * something smarter
1771 	 */
1772 	if (error_code & (ESR_DLK|ESR_ILK))
1773 		_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1774 	return;
1775 }
1776 #endif /* CONFIG_FSL_BOOKE */
1777 
1778 #ifdef CONFIG_SPE
1779 void SPEFloatingPointException(struct pt_regs *regs)
1780 {
1781 	extern int do_spe_mathemu(struct pt_regs *regs);
1782 	unsigned long spefscr;
1783 	int fpexc_mode;
1784 	int code = 0;
1785 	int err;
1786 
1787 	flush_spe_to_thread(current);
1788 
1789 	spefscr = current->thread.spefscr;
1790 	fpexc_mode = current->thread.fpexc_mode;
1791 
1792 	if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
1793 		code = FPE_FLTOVF;
1794 	}
1795 	else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
1796 		code = FPE_FLTUND;
1797 	}
1798 	else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
1799 		code = FPE_FLTDIV;
1800 	else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
1801 		code = FPE_FLTINV;
1802 	}
1803 	else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
1804 		code = FPE_FLTRES;
1805 
1806 	err = do_spe_mathemu(regs);
1807 	if (err == 0) {
1808 		regs->nip += 4;		/* skip emulated instruction */
1809 		emulate_single_step(regs);
1810 		return;
1811 	}
1812 
1813 	if (err == -EFAULT) {
1814 		/* got an error reading the instruction */
1815 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1816 	} else if (err == -EINVAL) {
1817 		/* didn't recognize the instruction */
1818 		printk(KERN_ERR "unrecognized spe instruction "
1819 		       "in %s at %lx\n", current->comm, regs->nip);
1820 	} else {
1821 		_exception(SIGFPE, regs, code, regs->nip);
1822 	}
1823 
1824 	return;
1825 }
1826 
1827 void SPEFloatingPointRoundException(struct pt_regs *regs)
1828 {
1829 	extern int speround_handler(struct pt_regs *regs);
1830 	int err;
1831 
1832 	preempt_disable();
1833 	if (regs->msr & MSR_SPE)
1834 		giveup_spe(current);
1835 	preempt_enable();
1836 
1837 	regs->nip -= 4;
1838 	err = speround_handler(regs);
1839 	if (err == 0) {
1840 		regs->nip += 4;		/* skip emulated instruction */
1841 		emulate_single_step(regs);
1842 		return;
1843 	}
1844 
1845 	if (err == -EFAULT) {
1846 		/* got an error reading the instruction */
1847 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1848 	} else if (err == -EINVAL) {
1849 		/* didn't recognize the instruction */
1850 		printk(KERN_ERR "unrecognized spe instruction "
1851 		       "in %s at %lx\n", current->comm, regs->nip);
1852 	} else {
1853 		_exception(SIGFPE, regs, 0, regs->nip);
1854 		return;
1855 	}
1856 }
1857 #endif
1858 
1859 /*
1860  * We enter here if we get an unrecoverable exception, that is, one
1861  * that happened at a point where the RI (recoverable interrupt) bit
1862  * in the MSR is 0.  This indicates that SRR0/1 are live, and that
1863  * we therefore lost state by taking this exception.
1864  */
1865 void unrecoverable_exception(struct pt_regs *regs)
1866 {
1867 	printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
1868 	       regs->trap, regs->nip);
1869 	die("Unrecoverable exception", regs, SIGABRT);
1870 }
1871 
1872 #if defined(CONFIG_BOOKE_WDT) || defined(CONFIG_40x)
1873 /*
1874  * Default handler for a Watchdog exception,
1875  * spins until a reboot occurs
1876  */
1877 void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
1878 {
1879 	/* Generic WatchdogHandler, implement your own */
1880 	mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
1881 	return;
1882 }
1883 
1884 void WatchdogException(struct pt_regs *regs)
1885 {
1886 	printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
1887 	WatchdogHandler(regs);
1888 }
1889 #endif
1890 
1891 /*
1892  * We enter here if we discover during exception entry that we are
1893  * running in supervisor mode with a userspace value in the stack pointer.
1894  */
1895 void kernel_bad_stack(struct pt_regs *regs)
1896 {
1897 	printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
1898 	       regs->gpr[1], regs->nip);
1899 	die("Bad kernel stack pointer", regs, SIGABRT);
1900 }
1901 
1902 void __init trap_init(void)
1903 {
1904 }
1905 
1906 
1907 #ifdef CONFIG_PPC_EMULATED_STATS
1908 
1909 #define WARN_EMULATED_SETUP(type)	.type = { .name = #type }
1910 
1911 struct ppc_emulated ppc_emulated = {
1912 #ifdef CONFIG_ALTIVEC
1913 	WARN_EMULATED_SETUP(altivec),
1914 #endif
1915 	WARN_EMULATED_SETUP(dcba),
1916 	WARN_EMULATED_SETUP(dcbz),
1917 	WARN_EMULATED_SETUP(fp_pair),
1918 	WARN_EMULATED_SETUP(isel),
1919 	WARN_EMULATED_SETUP(mcrxr),
1920 	WARN_EMULATED_SETUP(mfpvr),
1921 	WARN_EMULATED_SETUP(multiple),
1922 	WARN_EMULATED_SETUP(popcntb),
1923 	WARN_EMULATED_SETUP(spe),
1924 	WARN_EMULATED_SETUP(string),
1925 	WARN_EMULATED_SETUP(sync),
1926 	WARN_EMULATED_SETUP(unaligned),
1927 #ifdef CONFIG_MATH_EMULATION
1928 	WARN_EMULATED_SETUP(math),
1929 #endif
1930 #ifdef CONFIG_VSX
1931 	WARN_EMULATED_SETUP(vsx),
1932 #endif
1933 #ifdef CONFIG_PPC64
1934 	WARN_EMULATED_SETUP(mfdscr),
1935 	WARN_EMULATED_SETUP(mtdscr),
1936 	WARN_EMULATED_SETUP(lq_stq),
1937 #endif
1938 };
1939 
1940 u32 ppc_warn_emulated;
1941 
1942 void ppc_warn_emulated_print(const char *type)
1943 {
1944 	pr_warn_ratelimited("%s used emulated %s instruction\n", current->comm,
1945 			    type);
1946 }
1947 
1948 static int __init ppc_warn_emulated_init(void)
1949 {
1950 	struct dentry *dir, *d;
1951 	unsigned int i;
1952 	struct ppc_emulated_entry *entries = (void *)&ppc_emulated;
1953 
1954 	if (!powerpc_debugfs_root)
1955 		return -ENODEV;
1956 
1957 	dir = debugfs_create_dir("emulated_instructions",
1958 				 powerpc_debugfs_root);
1959 	if (!dir)
1960 		return -ENOMEM;
1961 
1962 	d = debugfs_create_u32("do_warn", S_IRUGO | S_IWUSR, dir,
1963 			       &ppc_warn_emulated);
1964 	if (!d)
1965 		goto fail;
1966 
1967 	for (i = 0; i < sizeof(ppc_emulated)/sizeof(*entries); i++) {
1968 		d = debugfs_create_u32(entries[i].name, S_IRUGO | S_IWUSR, dir,
1969 				       (u32 *)&entries[i].val.counter);
1970 		if (!d)
1971 			goto fail;
1972 	}
1973 
1974 	return 0;
1975 
1976 fail:
1977 	debugfs_remove_recursive(dir);
1978 	return -ENOMEM;
1979 }
1980 
1981 device_initcall(ppc_warn_emulated_init);
1982 
1983 #endif /* CONFIG_PPC_EMULATED_STATS */
1984