xref: /openbmc/linux/arch/powerpc/kernel/traps.c (revision e5c86679)
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/sched/debug.h>
21 #include <linux/kernel.h>
22 #include <linux/mm.h>
23 #include <linux/stddef.h>
24 #include <linux/unistd.h>
25 #include <linux/ptrace.h>
26 #include <linux/user.h>
27 #include <linux/interrupt.h>
28 #include <linux/init.h>
29 #include <linux/extable.h>
30 #include <linux/module.h>	/* print_modules */
31 #include <linux/prctl.h>
32 #include <linux/delay.h>
33 #include <linux/kprobes.h>
34 #include <linux/kexec.h>
35 #include <linux/backlight.h>
36 #include <linux/bug.h>
37 #include <linux/kdebug.h>
38 #include <linux/debugfs.h>
39 #include <linux/ratelimit.h>
40 #include <linux/context_tracking.h>
41 
42 #include <asm/emulated_ops.h>
43 #include <asm/pgtable.h>
44 #include <linux/uaccess.h>
45 #include <asm/io.h>
46 #include <asm/machdep.h>
47 #include <asm/rtas.h>
48 #include <asm/pmc.h>
49 #include <asm/reg.h>
50 #ifdef CONFIG_PMAC_BACKLIGHT
51 #include <asm/backlight.h>
52 #endif
53 #ifdef CONFIG_PPC64
54 #include <asm/firmware.h>
55 #include <asm/processor.h>
56 #include <asm/tm.h>
57 #endif
58 #include <asm/kexec.h>
59 #include <asm/ppc-opcode.h>
60 #include <asm/rio.h>
61 #include <asm/fadump.h>
62 #include <asm/switch_to.h>
63 #include <asm/tm.h>
64 #include <asm/debug.h>
65 #include <asm/asm-prototypes.h>
66 #include <asm/hmi.h>
67 #include <sysdev/fsl_pci.h>
68 #include <asm/kprobes.h>
69 
70 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC_CORE)
71 int (*__debugger)(struct pt_regs *regs) __read_mostly;
72 int (*__debugger_ipi)(struct pt_regs *regs) __read_mostly;
73 int (*__debugger_bpt)(struct pt_regs *regs) __read_mostly;
74 int (*__debugger_sstep)(struct pt_regs *regs) __read_mostly;
75 int (*__debugger_iabr_match)(struct pt_regs *regs) __read_mostly;
76 int (*__debugger_break_match)(struct pt_regs *regs) __read_mostly;
77 int (*__debugger_fault_handler)(struct pt_regs *regs) __read_mostly;
78 
79 EXPORT_SYMBOL(__debugger);
80 EXPORT_SYMBOL(__debugger_ipi);
81 EXPORT_SYMBOL(__debugger_bpt);
82 EXPORT_SYMBOL(__debugger_sstep);
83 EXPORT_SYMBOL(__debugger_iabr_match);
84 EXPORT_SYMBOL(__debugger_break_match);
85 EXPORT_SYMBOL(__debugger_fault_handler);
86 #endif
87 
88 /* Transactional Memory trap debug */
89 #ifdef TM_DEBUG_SW
90 #define TM_DEBUG(x...) printk(KERN_INFO x)
91 #else
92 #define TM_DEBUG(x...) do { } while(0)
93 #endif
94 
95 /*
96  * Trap & Exception support
97  */
98 
99 #ifdef CONFIG_PMAC_BACKLIGHT
100 static void pmac_backlight_unblank(void)
101 {
102 	mutex_lock(&pmac_backlight_mutex);
103 	if (pmac_backlight) {
104 		struct backlight_properties *props;
105 
106 		props = &pmac_backlight->props;
107 		props->brightness = props->max_brightness;
108 		props->power = FB_BLANK_UNBLANK;
109 		backlight_update_status(pmac_backlight);
110 	}
111 	mutex_unlock(&pmac_backlight_mutex);
112 }
113 #else
114 static inline void pmac_backlight_unblank(void) { }
115 #endif
116 
117 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
118 static int die_owner = -1;
119 static unsigned int die_nest_count;
120 static int die_counter;
121 
122 static unsigned long oops_begin(struct pt_regs *regs)
123 {
124 	int cpu;
125 	unsigned long flags;
126 
127 	oops_enter();
128 
129 	/* racy, but better than risking deadlock. */
130 	raw_local_irq_save(flags);
131 	cpu = smp_processor_id();
132 	if (!arch_spin_trylock(&die_lock)) {
133 		if (cpu == die_owner)
134 			/* nested oops. should stop eventually */;
135 		else
136 			arch_spin_lock(&die_lock);
137 	}
138 	die_nest_count++;
139 	die_owner = cpu;
140 	console_verbose();
141 	bust_spinlocks(1);
142 	if (machine_is(powermac))
143 		pmac_backlight_unblank();
144 	return flags;
145 }
146 NOKPROBE_SYMBOL(oops_begin);
147 
148 static void oops_end(unsigned long flags, struct pt_regs *regs,
149 			       int signr)
150 {
151 	bust_spinlocks(0);
152 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
153 	die_nest_count--;
154 	oops_exit();
155 	printk("\n");
156 	if (!die_nest_count) {
157 		/* Nest count reaches zero, release the lock. */
158 		die_owner = -1;
159 		arch_spin_unlock(&die_lock);
160 	}
161 	raw_local_irq_restore(flags);
162 
163 	crash_fadump(regs, "die oops");
164 
165 	/*
166 	 * A system reset (0x100) is a request to dump, so we always send
167 	 * it through the crashdump code.
168 	 */
169 	if (kexec_should_crash(current) || (TRAP(regs) == 0x100)) {
170 		crash_kexec(regs);
171 
172 		/*
173 		 * We aren't the primary crash CPU. We need to send it
174 		 * to a holding pattern to avoid it ending up in the panic
175 		 * code.
176 		 */
177 		crash_kexec_secondary(regs);
178 	}
179 
180 	if (!signr)
181 		return;
182 
183 	/*
184 	 * While our oops output is serialised by a spinlock, output
185 	 * from panic() called below can race and corrupt it. If we
186 	 * know we are going to panic, delay for 1 second so we have a
187 	 * chance to get clean backtraces from all CPUs that are oopsing.
188 	 */
189 	if (in_interrupt() || panic_on_oops || !current->pid ||
190 	    is_global_init(current)) {
191 		mdelay(MSEC_PER_SEC);
192 	}
193 
194 	if (in_interrupt())
195 		panic("Fatal exception in interrupt");
196 	if (panic_on_oops)
197 		panic("Fatal exception");
198 	do_exit(signr);
199 }
200 NOKPROBE_SYMBOL(oops_end);
201 
202 static int __die(const char *str, struct pt_regs *regs, long err)
203 {
204 	printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
205 #ifdef CONFIG_PREEMPT
206 	printk("PREEMPT ");
207 #endif
208 #ifdef CONFIG_SMP
209 	printk("SMP NR_CPUS=%d ", NR_CPUS);
210 #endif
211 	if (debug_pagealloc_enabled())
212 		printk("DEBUG_PAGEALLOC ");
213 #ifdef CONFIG_NUMA
214 	printk("NUMA ");
215 #endif
216 	printk("%s\n", ppc_md.name ? ppc_md.name : "");
217 
218 	if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV) == NOTIFY_STOP)
219 		return 1;
220 
221 	print_modules();
222 	show_regs(regs);
223 
224 	return 0;
225 }
226 NOKPROBE_SYMBOL(__die);
227 
228 void die(const char *str, struct pt_regs *regs, long err)
229 {
230 	unsigned long flags;
231 
232 	if (debugger(regs))
233 		return;
234 
235 	flags = oops_begin(regs);
236 	if (__die(str, regs, err))
237 		err = 0;
238 	oops_end(flags, regs, err);
239 }
240 
241 void user_single_step_siginfo(struct task_struct *tsk,
242 				struct pt_regs *regs, siginfo_t *info)
243 {
244 	memset(info, 0, sizeof(*info));
245 	info->si_signo = SIGTRAP;
246 	info->si_code = TRAP_TRACE;
247 	info->si_addr = (void __user *)regs->nip;
248 }
249 
250 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
251 {
252 	siginfo_t info;
253 	const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \
254 			"at %08lx nip %08lx lr %08lx code %x\n";
255 	const char fmt64[] = KERN_INFO "%s[%d]: unhandled signal %d " \
256 			"at %016lx nip %016lx lr %016lx code %x\n";
257 
258 	if (!user_mode(regs)) {
259 		die("Exception in kernel mode", regs, signr);
260 		return;
261 	}
262 
263 	if (show_unhandled_signals && unhandled_signal(current, signr)) {
264 		printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
265 				   current->comm, current->pid, signr,
266 				   addr, regs->nip, regs->link, code);
267 	}
268 
269 	if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
270 		local_irq_enable();
271 
272 	current->thread.trap_nr = code;
273 	memset(&info, 0, sizeof(info));
274 	info.si_signo = signr;
275 	info.si_code = code;
276 	info.si_addr = (void __user *) addr;
277 	force_sig_info(signr, &info, current);
278 }
279 
280 void system_reset_exception(struct pt_regs *regs)
281 {
282 	/* See if any machine dependent calls */
283 	if (ppc_md.system_reset_exception) {
284 		if (ppc_md.system_reset_exception(regs))
285 			return;
286 	}
287 
288 	die("System Reset", regs, SIGABRT);
289 
290 	/* Must die if the interrupt is not recoverable */
291 	if (!(regs->msr & MSR_RI))
292 		panic("Unrecoverable System Reset");
293 
294 	/* What should we do here? We could issue a shutdown or hard reset. */
295 }
296 
297 #ifdef CONFIG_PPC64
298 /*
299  * This function is called in real mode. Strictly no printk's please.
300  *
301  * regs->nip and regs->msr contains srr0 and ssr1.
302  */
303 long machine_check_early(struct pt_regs *regs)
304 {
305 	long handled = 0;
306 
307 	__this_cpu_inc(irq_stat.mce_exceptions);
308 
309 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
310 
311 	if (cur_cpu_spec && cur_cpu_spec->machine_check_early)
312 		handled = cur_cpu_spec->machine_check_early(regs);
313 	return handled;
314 }
315 
316 long hmi_exception_realmode(struct pt_regs *regs)
317 {
318 	__this_cpu_inc(irq_stat.hmi_exceptions);
319 
320 	wait_for_subcore_guest_exit();
321 
322 	if (ppc_md.hmi_exception_early)
323 		ppc_md.hmi_exception_early(regs);
324 
325 	wait_for_tb_resync();
326 
327 	return 0;
328 }
329 
330 #endif
331 
332 /*
333  * I/O accesses can cause machine checks on powermacs.
334  * Check if the NIP corresponds to the address of a sync
335  * instruction for which there is an entry in the exception
336  * table.
337  * Note that the 601 only takes a machine check on TEA
338  * (transfer error ack) signal assertion, and does not
339  * set any of the top 16 bits of SRR1.
340  *  -- paulus.
341  */
342 static inline int check_io_access(struct pt_regs *regs)
343 {
344 #ifdef CONFIG_PPC32
345 	unsigned long msr = regs->msr;
346 	const struct exception_table_entry *entry;
347 	unsigned int *nip = (unsigned int *)regs->nip;
348 
349 	if (((msr & 0xffff0000) == 0 || (msr & (0x80000 | 0x40000)))
350 	    && (entry = search_exception_tables(regs->nip)) != NULL) {
351 		/*
352 		 * Check that it's a sync instruction, or somewhere
353 		 * in the twi; isync; nop sequence that inb/inw/inl uses.
354 		 * As the address is in the exception table
355 		 * we should be able to read the instr there.
356 		 * For the debug message, we look at the preceding
357 		 * load or store.
358 		 */
359 		if (*nip == PPC_INST_NOP)
360 			nip -= 2;
361 		else if (*nip == PPC_INST_ISYNC)
362 			--nip;
363 		if (*nip == PPC_INST_SYNC || (*nip >> 26) == OP_TRAP) {
364 			unsigned int rb;
365 
366 			--nip;
367 			rb = (*nip >> 11) & 0x1f;
368 			printk(KERN_DEBUG "%s bad port %lx at %p\n",
369 			       (*nip & 0x100)? "OUT to": "IN from",
370 			       regs->gpr[rb] - _IO_BASE, nip);
371 			regs->msr |= MSR_RI;
372 			regs->nip = extable_fixup(entry);
373 			return 1;
374 		}
375 	}
376 #endif /* CONFIG_PPC32 */
377 	return 0;
378 }
379 
380 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
381 /* On 4xx, the reason for the machine check or program exception
382    is in the ESR. */
383 #define get_reason(regs)	((regs)->dsisr)
384 #ifndef CONFIG_FSL_BOOKE
385 #define get_mc_reason(regs)	((regs)->dsisr)
386 #else
387 #define get_mc_reason(regs)	(mfspr(SPRN_MCSR))
388 #endif
389 #define REASON_FP		ESR_FP
390 #define REASON_ILLEGAL		(ESR_PIL | ESR_PUO)
391 #define REASON_PRIVILEGED	ESR_PPR
392 #define REASON_TRAP		ESR_PTR
393 
394 /* single-step stuff */
395 #define single_stepping(regs)	(current->thread.debug.dbcr0 & DBCR0_IC)
396 #define clear_single_step(regs)	(current->thread.debug.dbcr0 &= ~DBCR0_IC)
397 
398 #else
399 /* On non-4xx, the reason for the machine check or program
400    exception is in the MSR. */
401 #define get_reason(regs)	((regs)->msr)
402 #define get_mc_reason(regs)	((regs)->msr)
403 #define REASON_TM		0x200000
404 #define REASON_FP		0x100000
405 #define REASON_ILLEGAL		0x80000
406 #define REASON_PRIVILEGED	0x40000
407 #define REASON_TRAP		0x20000
408 
409 #define single_stepping(regs)	((regs)->msr & MSR_SE)
410 #define clear_single_step(regs)	((regs)->msr &= ~MSR_SE)
411 #endif
412 
413 #if defined(CONFIG_4xx)
414 int machine_check_4xx(struct pt_regs *regs)
415 {
416 	unsigned long reason = get_mc_reason(regs);
417 
418 	if (reason & ESR_IMCP) {
419 		printk("Instruction");
420 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
421 	} else
422 		printk("Data");
423 	printk(" machine check in kernel mode.\n");
424 
425 	return 0;
426 }
427 
428 int machine_check_440A(struct pt_regs *regs)
429 {
430 	unsigned long reason = get_mc_reason(regs);
431 
432 	printk("Machine check in kernel mode.\n");
433 	if (reason & ESR_IMCP){
434 		printk("Instruction Synchronous Machine Check exception\n");
435 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
436 	}
437 	else {
438 		u32 mcsr = mfspr(SPRN_MCSR);
439 		if (mcsr & MCSR_IB)
440 			printk("Instruction Read PLB Error\n");
441 		if (mcsr & MCSR_DRB)
442 			printk("Data Read PLB Error\n");
443 		if (mcsr & MCSR_DWB)
444 			printk("Data Write PLB Error\n");
445 		if (mcsr & MCSR_TLBP)
446 			printk("TLB Parity Error\n");
447 		if (mcsr & MCSR_ICP){
448 			flush_instruction_cache();
449 			printk("I-Cache Parity Error\n");
450 		}
451 		if (mcsr & MCSR_DCSP)
452 			printk("D-Cache Search Parity Error\n");
453 		if (mcsr & MCSR_DCFP)
454 			printk("D-Cache Flush Parity Error\n");
455 		if (mcsr & MCSR_IMPE)
456 			printk("Machine Check exception is imprecise\n");
457 
458 		/* Clear MCSR */
459 		mtspr(SPRN_MCSR, mcsr);
460 	}
461 	return 0;
462 }
463 
464 int machine_check_47x(struct pt_regs *regs)
465 {
466 	unsigned long reason = get_mc_reason(regs);
467 	u32 mcsr;
468 
469 	printk(KERN_ERR "Machine check in kernel mode.\n");
470 	if (reason & ESR_IMCP) {
471 		printk(KERN_ERR
472 		       "Instruction Synchronous Machine Check exception\n");
473 		mtspr(SPRN_ESR, reason & ~ESR_IMCP);
474 		return 0;
475 	}
476 	mcsr = mfspr(SPRN_MCSR);
477 	if (mcsr & MCSR_IB)
478 		printk(KERN_ERR "Instruction Read PLB Error\n");
479 	if (mcsr & MCSR_DRB)
480 		printk(KERN_ERR "Data Read PLB Error\n");
481 	if (mcsr & MCSR_DWB)
482 		printk(KERN_ERR "Data Write PLB Error\n");
483 	if (mcsr & MCSR_TLBP)
484 		printk(KERN_ERR "TLB Parity Error\n");
485 	if (mcsr & MCSR_ICP) {
486 		flush_instruction_cache();
487 		printk(KERN_ERR "I-Cache Parity Error\n");
488 	}
489 	if (mcsr & MCSR_DCSP)
490 		printk(KERN_ERR "D-Cache Search Parity Error\n");
491 	if (mcsr & PPC47x_MCSR_GPR)
492 		printk(KERN_ERR "GPR Parity Error\n");
493 	if (mcsr & PPC47x_MCSR_FPR)
494 		printk(KERN_ERR "FPR Parity Error\n");
495 	if (mcsr & PPC47x_MCSR_IPR)
496 		printk(KERN_ERR "Machine Check exception is imprecise\n");
497 
498 	/* Clear MCSR */
499 	mtspr(SPRN_MCSR, mcsr);
500 
501 	return 0;
502 }
503 #elif defined(CONFIG_E500)
504 int machine_check_e500mc(struct pt_regs *regs)
505 {
506 	unsigned long mcsr = mfspr(SPRN_MCSR);
507 	unsigned long reason = mcsr;
508 	int recoverable = 1;
509 
510 	if (reason & MCSR_LD) {
511 		recoverable = fsl_rio_mcheck_exception(regs);
512 		if (recoverable == 1)
513 			goto silent_out;
514 	}
515 
516 	printk("Machine check in kernel mode.\n");
517 	printk("Caused by (from MCSR=%lx): ", reason);
518 
519 	if (reason & MCSR_MCP)
520 		printk("Machine Check Signal\n");
521 
522 	if (reason & MCSR_ICPERR) {
523 		printk("Instruction Cache Parity Error\n");
524 
525 		/*
526 		 * This is recoverable by invalidating the i-cache.
527 		 */
528 		mtspr(SPRN_L1CSR1, mfspr(SPRN_L1CSR1) | L1CSR1_ICFI);
529 		while (mfspr(SPRN_L1CSR1) & L1CSR1_ICFI)
530 			;
531 
532 		/*
533 		 * This will generally be accompanied by an instruction
534 		 * fetch error report -- only treat MCSR_IF as fatal
535 		 * if it wasn't due to an L1 parity error.
536 		 */
537 		reason &= ~MCSR_IF;
538 	}
539 
540 	if (reason & MCSR_DCPERR_MC) {
541 		printk("Data Cache Parity Error\n");
542 
543 		/*
544 		 * In write shadow mode we auto-recover from the error, but it
545 		 * may still get logged and cause a machine check.  We should
546 		 * only treat the non-write shadow case as non-recoverable.
547 		 */
548 		if (!(mfspr(SPRN_L1CSR2) & L1CSR2_DCWS))
549 			recoverable = 0;
550 	}
551 
552 	if (reason & MCSR_L2MMU_MHIT) {
553 		printk("Hit on multiple TLB entries\n");
554 		recoverable = 0;
555 	}
556 
557 	if (reason & MCSR_NMI)
558 		printk("Non-maskable interrupt\n");
559 
560 	if (reason & MCSR_IF) {
561 		printk("Instruction Fetch Error Report\n");
562 		recoverable = 0;
563 	}
564 
565 	if (reason & MCSR_LD) {
566 		printk("Load Error Report\n");
567 		recoverable = 0;
568 	}
569 
570 	if (reason & MCSR_ST) {
571 		printk("Store Error Report\n");
572 		recoverable = 0;
573 	}
574 
575 	if (reason & MCSR_LDG) {
576 		printk("Guarded Load Error Report\n");
577 		recoverable = 0;
578 	}
579 
580 	if (reason & MCSR_TLBSYNC)
581 		printk("Simultaneous tlbsync operations\n");
582 
583 	if (reason & MCSR_BSL2_ERR) {
584 		printk("Level 2 Cache Error\n");
585 		recoverable = 0;
586 	}
587 
588 	if (reason & MCSR_MAV) {
589 		u64 addr;
590 
591 		addr = mfspr(SPRN_MCAR);
592 		addr |= (u64)mfspr(SPRN_MCARU) << 32;
593 
594 		printk("Machine Check %s Address: %#llx\n",
595 		       reason & MCSR_MEA ? "Effective" : "Physical", addr);
596 	}
597 
598 silent_out:
599 	mtspr(SPRN_MCSR, mcsr);
600 	return mfspr(SPRN_MCSR) == 0 && recoverable;
601 }
602 
603 int machine_check_e500(struct pt_regs *regs)
604 {
605 	unsigned long reason = get_mc_reason(regs);
606 
607 	if (reason & MCSR_BUS_RBERR) {
608 		if (fsl_rio_mcheck_exception(regs))
609 			return 1;
610 		if (fsl_pci_mcheck_exception(regs))
611 			return 1;
612 	}
613 
614 	printk("Machine check in kernel mode.\n");
615 	printk("Caused by (from MCSR=%lx): ", reason);
616 
617 	if (reason & MCSR_MCP)
618 		printk("Machine Check Signal\n");
619 	if (reason & MCSR_ICPERR)
620 		printk("Instruction Cache Parity Error\n");
621 	if (reason & MCSR_DCP_PERR)
622 		printk("Data Cache Push Parity Error\n");
623 	if (reason & MCSR_DCPERR)
624 		printk("Data Cache Parity Error\n");
625 	if (reason & MCSR_BUS_IAERR)
626 		printk("Bus - Instruction Address Error\n");
627 	if (reason & MCSR_BUS_RAERR)
628 		printk("Bus - Read Address Error\n");
629 	if (reason & MCSR_BUS_WAERR)
630 		printk("Bus - Write Address Error\n");
631 	if (reason & MCSR_BUS_IBERR)
632 		printk("Bus - Instruction Data Error\n");
633 	if (reason & MCSR_BUS_RBERR)
634 		printk("Bus - Read Data Bus Error\n");
635 	if (reason & MCSR_BUS_WBERR)
636 		printk("Bus - Write Data Bus Error\n");
637 	if (reason & MCSR_BUS_IPERR)
638 		printk("Bus - Instruction Parity Error\n");
639 	if (reason & MCSR_BUS_RPERR)
640 		printk("Bus - Read Parity Error\n");
641 
642 	return 0;
643 }
644 
645 int machine_check_generic(struct pt_regs *regs)
646 {
647 	return 0;
648 }
649 #elif defined(CONFIG_E200)
650 int machine_check_e200(struct pt_regs *regs)
651 {
652 	unsigned long reason = get_mc_reason(regs);
653 
654 	printk("Machine check in kernel mode.\n");
655 	printk("Caused by (from MCSR=%lx): ", reason);
656 
657 	if (reason & MCSR_MCP)
658 		printk("Machine Check Signal\n");
659 	if (reason & MCSR_CP_PERR)
660 		printk("Cache Push Parity Error\n");
661 	if (reason & MCSR_CPERR)
662 		printk("Cache Parity Error\n");
663 	if (reason & MCSR_EXCP_ERR)
664 		printk("ISI, ITLB, or Bus Error on first instruction fetch for an exception handler\n");
665 	if (reason & MCSR_BUS_IRERR)
666 		printk("Bus - Read Bus Error on instruction fetch\n");
667 	if (reason & MCSR_BUS_DRERR)
668 		printk("Bus - Read Bus Error on data load\n");
669 	if (reason & MCSR_BUS_WRERR)
670 		printk("Bus - Write Bus Error on buffered store or cache line push\n");
671 
672 	return 0;
673 }
674 #elif defined(CONFIG_PPC_8xx)
675 int machine_check_8xx(struct pt_regs *regs)
676 {
677 	unsigned long reason = get_mc_reason(regs);
678 
679 	pr_err("Machine check in kernel mode.\n");
680 	pr_err("Caused by (from SRR1=%lx): ", reason);
681 	if (reason & 0x40000000)
682 		pr_err("Fetch error at address %lx\n", regs->nip);
683 	else
684 		pr_err("Data access error at address %lx\n", regs->dar);
685 
686 #ifdef CONFIG_PCI
687 	/* the qspan pci read routines can cause machine checks -- Cort
688 	 *
689 	 * yuck !!! that totally needs to go away ! There are better ways
690 	 * to deal with that than having a wart in the mcheck handler.
691 	 * -- BenH
692 	 */
693 	bad_page_fault(regs, regs->dar, SIGBUS);
694 	return 1;
695 #else
696 	return 0;
697 #endif
698 }
699 #else
700 int machine_check_generic(struct pt_regs *regs)
701 {
702 	unsigned long reason = get_mc_reason(regs);
703 
704 	printk("Machine check in kernel mode.\n");
705 	printk("Caused by (from SRR1=%lx): ", reason);
706 	switch (reason & 0x601F0000) {
707 	case 0x80000:
708 		printk("Machine check signal\n");
709 		break;
710 	case 0:		/* for 601 */
711 	case 0x40000:
712 	case 0x140000:	/* 7450 MSS error and TEA */
713 		printk("Transfer error ack signal\n");
714 		break;
715 	case 0x20000:
716 		printk("Data parity error signal\n");
717 		break;
718 	case 0x10000:
719 		printk("Address parity error signal\n");
720 		break;
721 	case 0x20000000:
722 		printk("L1 Data Cache error\n");
723 		break;
724 	case 0x40000000:
725 		printk("L1 Instruction Cache error\n");
726 		break;
727 	case 0x00100000:
728 		printk("L2 data cache parity error\n");
729 		break;
730 	default:
731 		printk("Unknown values in msr\n");
732 	}
733 	return 0;
734 }
735 #endif /* everything else */
736 
737 void machine_check_exception(struct pt_regs *regs)
738 {
739 	enum ctx_state prev_state = exception_enter();
740 	int recover = 0;
741 
742 	__this_cpu_inc(irq_stat.mce_exceptions);
743 
744 	/* See if any machine dependent calls. In theory, we would want
745 	 * to call the CPU first, and call the ppc_md. one if the CPU
746 	 * one returns a positive number. However there is existing code
747 	 * that assumes the board gets a first chance, so let's keep it
748 	 * that way for now and fix things later. --BenH.
749 	 */
750 	if (ppc_md.machine_check_exception)
751 		recover = ppc_md.machine_check_exception(regs);
752 	else if (cur_cpu_spec->machine_check)
753 		recover = cur_cpu_spec->machine_check(regs);
754 
755 	if (recover > 0)
756 		goto bail;
757 
758 	if (debugger_fault_handler(regs))
759 		goto bail;
760 
761 	if (check_io_access(regs))
762 		goto bail;
763 
764 	die("Machine check", regs, SIGBUS);
765 
766 	/* Must die if the interrupt is not recoverable */
767 	if (!(regs->msr & MSR_RI))
768 		panic("Unrecoverable Machine check");
769 
770 bail:
771 	exception_exit(prev_state);
772 }
773 
774 void SMIException(struct pt_regs *regs)
775 {
776 	die("System Management Interrupt", regs, SIGABRT);
777 }
778 
779 void handle_hmi_exception(struct pt_regs *regs)
780 {
781 	struct pt_regs *old_regs;
782 
783 	old_regs = set_irq_regs(regs);
784 	irq_enter();
785 
786 	if (ppc_md.handle_hmi_exception)
787 		ppc_md.handle_hmi_exception(regs);
788 
789 	irq_exit();
790 	set_irq_regs(old_regs);
791 }
792 
793 void unknown_exception(struct pt_regs *regs)
794 {
795 	enum ctx_state prev_state = exception_enter();
796 
797 	printk("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
798 	       regs->nip, regs->msr, regs->trap);
799 
800 	_exception(SIGTRAP, regs, 0, 0);
801 
802 	exception_exit(prev_state);
803 }
804 
805 void instruction_breakpoint_exception(struct pt_regs *regs)
806 {
807 	enum ctx_state prev_state = exception_enter();
808 
809 	if (notify_die(DIE_IABR_MATCH, "iabr_match", regs, 5,
810 					5, SIGTRAP) == NOTIFY_STOP)
811 		goto bail;
812 	if (debugger_iabr_match(regs))
813 		goto bail;
814 	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
815 
816 bail:
817 	exception_exit(prev_state);
818 }
819 
820 void RunModeException(struct pt_regs *regs)
821 {
822 	_exception(SIGTRAP, regs, 0, 0);
823 }
824 
825 void single_step_exception(struct pt_regs *regs)
826 {
827 	enum ctx_state prev_state = exception_enter();
828 
829 	clear_single_step(regs);
830 
831 	if (kprobe_post_handler(regs))
832 		return;
833 
834 	if (notify_die(DIE_SSTEP, "single_step", regs, 5,
835 					5, SIGTRAP) == NOTIFY_STOP)
836 		goto bail;
837 	if (debugger_sstep(regs))
838 		goto bail;
839 
840 	_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
841 
842 bail:
843 	exception_exit(prev_state);
844 }
845 NOKPROBE_SYMBOL(single_step_exception);
846 
847 /*
848  * After we have successfully emulated an instruction, we have to
849  * check if the instruction was being single-stepped, and if so,
850  * pretend we got a single-step exception.  This was pointed out
851  * by Kumar Gala.  -- paulus
852  */
853 static void emulate_single_step(struct pt_regs *regs)
854 {
855 	if (single_stepping(regs))
856 		single_step_exception(regs);
857 }
858 
859 static inline int __parse_fpscr(unsigned long fpscr)
860 {
861 	int ret = 0;
862 
863 	/* Invalid operation */
864 	if ((fpscr & FPSCR_VE) && (fpscr & FPSCR_VX))
865 		ret = FPE_FLTINV;
866 
867 	/* Overflow */
868 	else if ((fpscr & FPSCR_OE) && (fpscr & FPSCR_OX))
869 		ret = FPE_FLTOVF;
870 
871 	/* Underflow */
872 	else if ((fpscr & FPSCR_UE) && (fpscr & FPSCR_UX))
873 		ret = FPE_FLTUND;
874 
875 	/* Divide by zero */
876 	else if ((fpscr & FPSCR_ZE) && (fpscr & FPSCR_ZX))
877 		ret = FPE_FLTDIV;
878 
879 	/* Inexact result */
880 	else if ((fpscr & FPSCR_XE) && (fpscr & FPSCR_XX))
881 		ret = FPE_FLTRES;
882 
883 	return ret;
884 }
885 
886 static void parse_fpe(struct pt_regs *regs)
887 {
888 	int code = 0;
889 
890 	flush_fp_to_thread(current);
891 
892 	code = __parse_fpscr(current->thread.fp_state.fpscr);
893 
894 	_exception(SIGFPE, regs, code, regs->nip);
895 }
896 
897 /*
898  * Illegal instruction emulation support.  Originally written to
899  * provide the PVR to user applications using the mfspr rd, PVR.
900  * Return non-zero if we can't emulate, or -EFAULT if the associated
901  * memory access caused an access fault.  Return zero on success.
902  *
903  * There are a couple of ways to do this, either "decode" the instruction
904  * or directly match lots of bits.  In this case, matching lots of
905  * bits is faster and easier.
906  *
907  */
908 static int emulate_string_inst(struct pt_regs *regs, u32 instword)
909 {
910 	u8 rT = (instword >> 21) & 0x1f;
911 	u8 rA = (instword >> 16) & 0x1f;
912 	u8 NB_RB = (instword >> 11) & 0x1f;
913 	u32 num_bytes;
914 	unsigned long EA;
915 	int pos = 0;
916 
917 	/* Early out if we are an invalid form of lswx */
918 	if ((instword & PPC_INST_STRING_MASK) == PPC_INST_LSWX)
919 		if ((rT == rA) || (rT == NB_RB))
920 			return -EINVAL;
921 
922 	EA = (rA == 0) ? 0 : regs->gpr[rA];
923 
924 	switch (instword & PPC_INST_STRING_MASK) {
925 		case PPC_INST_LSWX:
926 		case PPC_INST_STSWX:
927 			EA += NB_RB;
928 			num_bytes = regs->xer & 0x7f;
929 			break;
930 		case PPC_INST_LSWI:
931 		case PPC_INST_STSWI:
932 			num_bytes = (NB_RB == 0) ? 32 : NB_RB;
933 			break;
934 		default:
935 			return -EINVAL;
936 	}
937 
938 	while (num_bytes != 0)
939 	{
940 		u8 val;
941 		u32 shift = 8 * (3 - (pos & 0x3));
942 
943 		/* if process is 32-bit, clear upper 32 bits of EA */
944 		if ((regs->msr & MSR_64BIT) == 0)
945 			EA &= 0xFFFFFFFF;
946 
947 		switch ((instword & PPC_INST_STRING_MASK)) {
948 			case PPC_INST_LSWX:
949 			case PPC_INST_LSWI:
950 				if (get_user(val, (u8 __user *)EA))
951 					return -EFAULT;
952 				/* first time updating this reg,
953 				 * zero it out */
954 				if (pos == 0)
955 					regs->gpr[rT] = 0;
956 				regs->gpr[rT] |= val << shift;
957 				break;
958 			case PPC_INST_STSWI:
959 			case PPC_INST_STSWX:
960 				val = regs->gpr[rT] >> shift;
961 				if (put_user(val, (u8 __user *)EA))
962 					return -EFAULT;
963 				break;
964 		}
965 		/* move EA to next address */
966 		EA += 1;
967 		num_bytes--;
968 
969 		/* manage our position within the register */
970 		if (++pos == 4) {
971 			pos = 0;
972 			if (++rT == 32)
973 				rT = 0;
974 		}
975 	}
976 
977 	return 0;
978 }
979 
980 static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword)
981 {
982 	u32 ra,rs;
983 	unsigned long tmp;
984 
985 	ra = (instword >> 16) & 0x1f;
986 	rs = (instword >> 21) & 0x1f;
987 
988 	tmp = regs->gpr[rs];
989 	tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL);
990 	tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL);
991 	tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
992 	regs->gpr[ra] = tmp;
993 
994 	return 0;
995 }
996 
997 static int emulate_isel(struct pt_regs *regs, u32 instword)
998 {
999 	u8 rT = (instword >> 21) & 0x1f;
1000 	u8 rA = (instword >> 16) & 0x1f;
1001 	u8 rB = (instword >> 11) & 0x1f;
1002 	u8 BC = (instword >> 6) & 0x1f;
1003 	u8 bit;
1004 	unsigned long tmp;
1005 
1006 	tmp = (rA == 0) ? 0 : regs->gpr[rA];
1007 	bit = (regs->ccr >> (31 - BC)) & 0x1;
1008 
1009 	regs->gpr[rT] = bit ? tmp : regs->gpr[rB];
1010 
1011 	return 0;
1012 }
1013 
1014 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1015 static inline bool tm_abort_check(struct pt_regs *regs, int cause)
1016 {
1017         /* If we're emulating a load/store in an active transaction, we cannot
1018          * emulate it as the kernel operates in transaction suspended context.
1019          * We need to abort the transaction.  This creates a persistent TM
1020          * abort so tell the user what caused it with a new code.
1021 	 */
1022 	if (MSR_TM_TRANSACTIONAL(regs->msr)) {
1023 		tm_enable();
1024 		tm_abort(cause);
1025 		return true;
1026 	}
1027 	return false;
1028 }
1029 #else
1030 static inline bool tm_abort_check(struct pt_regs *regs, int reason)
1031 {
1032 	return false;
1033 }
1034 #endif
1035 
1036 static int emulate_instruction(struct pt_regs *regs)
1037 {
1038 	u32 instword;
1039 	u32 rd;
1040 
1041 	if (!user_mode(regs))
1042 		return -EINVAL;
1043 	CHECK_FULL_REGS(regs);
1044 
1045 	if (get_user(instword, (u32 __user *)(regs->nip)))
1046 		return -EFAULT;
1047 
1048 	/* Emulate the mfspr rD, PVR. */
1049 	if ((instword & PPC_INST_MFSPR_PVR_MASK) == PPC_INST_MFSPR_PVR) {
1050 		PPC_WARN_EMULATED(mfpvr, regs);
1051 		rd = (instword >> 21) & 0x1f;
1052 		regs->gpr[rd] = mfspr(SPRN_PVR);
1053 		return 0;
1054 	}
1055 
1056 	/* Emulating the dcba insn is just a no-op.  */
1057 	if ((instword & PPC_INST_DCBA_MASK) == PPC_INST_DCBA) {
1058 		PPC_WARN_EMULATED(dcba, regs);
1059 		return 0;
1060 	}
1061 
1062 	/* Emulate the mcrxr insn.  */
1063 	if ((instword & PPC_INST_MCRXR_MASK) == PPC_INST_MCRXR) {
1064 		int shift = (instword >> 21) & 0x1c;
1065 		unsigned long msk = 0xf0000000UL >> shift;
1066 
1067 		PPC_WARN_EMULATED(mcrxr, regs);
1068 		regs->ccr = (regs->ccr & ~msk) | ((regs->xer >> shift) & msk);
1069 		regs->xer &= ~0xf0000000UL;
1070 		return 0;
1071 	}
1072 
1073 	/* Emulate load/store string insn. */
1074 	if ((instword & PPC_INST_STRING_GEN_MASK) == PPC_INST_STRING) {
1075 		if (tm_abort_check(regs,
1076 				   TM_CAUSE_EMULATE | TM_CAUSE_PERSISTENT))
1077 			return -EINVAL;
1078 		PPC_WARN_EMULATED(string, regs);
1079 		return emulate_string_inst(regs, instword);
1080 	}
1081 
1082 	/* Emulate the popcntb (Population Count Bytes) instruction. */
1083 	if ((instword & PPC_INST_POPCNTB_MASK) == PPC_INST_POPCNTB) {
1084 		PPC_WARN_EMULATED(popcntb, regs);
1085 		return emulate_popcntb_inst(regs, instword);
1086 	}
1087 
1088 	/* Emulate isel (Integer Select) instruction */
1089 	if ((instword & PPC_INST_ISEL_MASK) == PPC_INST_ISEL) {
1090 		PPC_WARN_EMULATED(isel, regs);
1091 		return emulate_isel(regs, instword);
1092 	}
1093 
1094 	/* Emulate sync instruction variants */
1095 	if ((instword & PPC_INST_SYNC_MASK) == PPC_INST_SYNC) {
1096 		PPC_WARN_EMULATED(sync, regs);
1097 		asm volatile("sync");
1098 		return 0;
1099 	}
1100 
1101 #ifdef CONFIG_PPC64
1102 	/* Emulate the mfspr rD, DSCR. */
1103 	if ((((instword & PPC_INST_MFSPR_DSCR_USER_MASK) ==
1104 		PPC_INST_MFSPR_DSCR_USER) ||
1105 	     ((instword & PPC_INST_MFSPR_DSCR_MASK) ==
1106 		PPC_INST_MFSPR_DSCR)) &&
1107 			cpu_has_feature(CPU_FTR_DSCR)) {
1108 		PPC_WARN_EMULATED(mfdscr, regs);
1109 		rd = (instword >> 21) & 0x1f;
1110 		regs->gpr[rd] = mfspr(SPRN_DSCR);
1111 		return 0;
1112 	}
1113 	/* Emulate the mtspr DSCR, rD. */
1114 	if ((((instword & PPC_INST_MTSPR_DSCR_USER_MASK) ==
1115 		PPC_INST_MTSPR_DSCR_USER) ||
1116 	     ((instword & PPC_INST_MTSPR_DSCR_MASK) ==
1117 		PPC_INST_MTSPR_DSCR)) &&
1118 			cpu_has_feature(CPU_FTR_DSCR)) {
1119 		PPC_WARN_EMULATED(mtdscr, regs);
1120 		rd = (instword >> 21) & 0x1f;
1121 		current->thread.dscr = regs->gpr[rd];
1122 		current->thread.dscr_inherit = 1;
1123 		mtspr(SPRN_DSCR, current->thread.dscr);
1124 		return 0;
1125 	}
1126 #endif
1127 
1128 	return -EINVAL;
1129 }
1130 
1131 int is_valid_bugaddr(unsigned long addr)
1132 {
1133 	return is_kernel_addr(addr);
1134 }
1135 
1136 #ifdef CONFIG_MATH_EMULATION
1137 static int emulate_math(struct pt_regs *regs)
1138 {
1139 	int ret;
1140 	extern int do_mathemu(struct pt_regs *regs);
1141 
1142 	ret = do_mathemu(regs);
1143 	if (ret >= 0)
1144 		PPC_WARN_EMULATED(math, regs);
1145 
1146 	switch (ret) {
1147 	case 0:
1148 		emulate_single_step(regs);
1149 		return 0;
1150 	case 1: {
1151 			int code = 0;
1152 			code = __parse_fpscr(current->thread.fp_state.fpscr);
1153 			_exception(SIGFPE, regs, code, regs->nip);
1154 			return 0;
1155 		}
1156 	case -EFAULT:
1157 		_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1158 		return 0;
1159 	}
1160 
1161 	return -1;
1162 }
1163 #else
1164 static inline int emulate_math(struct pt_regs *regs) { return -1; }
1165 #endif
1166 
1167 void program_check_exception(struct pt_regs *regs)
1168 {
1169 	enum ctx_state prev_state = exception_enter();
1170 	unsigned int reason = get_reason(regs);
1171 
1172 	/* We can now get here via a FP Unavailable exception if the core
1173 	 * has no FPU, in that case the reason flags will be 0 */
1174 
1175 	if (reason & REASON_FP) {
1176 		/* IEEE FP exception */
1177 		parse_fpe(regs);
1178 		goto bail;
1179 	}
1180 	if (reason & REASON_TRAP) {
1181 		unsigned long bugaddr;
1182 		/* Debugger is first in line to stop recursive faults in
1183 		 * rcu_lock, notify_die, or atomic_notifier_call_chain */
1184 		if (debugger_bpt(regs))
1185 			goto bail;
1186 
1187 		if (kprobe_handler(regs))
1188 			goto bail;
1189 
1190 		/* trap exception */
1191 		if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
1192 				== NOTIFY_STOP)
1193 			goto bail;
1194 
1195 		bugaddr = regs->nip;
1196 		/*
1197 		 * Fixup bugaddr for BUG_ON() in real mode
1198 		 */
1199 		if (!is_kernel_addr(bugaddr) && !(regs->msr & MSR_IR))
1200 			bugaddr += PAGE_OFFSET;
1201 
1202 		if (!(regs->msr & MSR_PR) &&  /* not user-mode */
1203 		    report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {
1204 			regs->nip += 4;
1205 			goto bail;
1206 		}
1207 		_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
1208 		goto bail;
1209 	}
1210 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1211 	if (reason & REASON_TM) {
1212 		/* This is a TM "Bad Thing Exception" program check.
1213 		 * This occurs when:
1214 		 * -  An rfid/hrfid/mtmsrd attempts to cause an illegal
1215 		 *    transition in TM states.
1216 		 * -  A trechkpt is attempted when transactional.
1217 		 * -  A treclaim is attempted when non transactional.
1218 		 * -  A tend is illegally attempted.
1219 		 * -  writing a TM SPR when transactional.
1220 		 */
1221 		if (!user_mode(regs) &&
1222 		    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
1223 			regs->nip += 4;
1224 			goto bail;
1225 		}
1226 		/* If usermode caused this, it's done something illegal and
1227 		 * gets a SIGILL slap on the wrist.  We call it an illegal
1228 		 * operand to distinguish from the instruction just being bad
1229 		 * (e.g. executing a 'tend' on a CPU without TM!); it's an
1230 		 * illegal /placement/ of a valid instruction.
1231 		 */
1232 		if (user_mode(regs)) {
1233 			_exception(SIGILL, regs, ILL_ILLOPN, regs->nip);
1234 			goto bail;
1235 		} else {
1236 			printk(KERN_EMERG "Unexpected TM Bad Thing exception "
1237 			       "at %lx (msr 0x%x)\n", regs->nip, reason);
1238 			die("Unrecoverable exception", regs, SIGABRT);
1239 		}
1240 	}
1241 #endif
1242 
1243 	/*
1244 	 * If we took the program check in the kernel skip down to sending a
1245 	 * SIGILL. The subsequent cases all relate to emulating instructions
1246 	 * which we should only do for userspace. We also do not want to enable
1247 	 * interrupts for kernel faults because that might lead to further
1248 	 * faults, and loose the context of the original exception.
1249 	 */
1250 	if (!user_mode(regs))
1251 		goto sigill;
1252 
1253 	/* We restore the interrupt state now */
1254 	if (!arch_irq_disabled_regs(regs))
1255 		local_irq_enable();
1256 
1257 	/* (reason & REASON_ILLEGAL) would be the obvious thing here,
1258 	 * but there seems to be a hardware bug on the 405GP (RevD)
1259 	 * that means ESR is sometimes set incorrectly - either to
1260 	 * ESR_DST (!?) or 0.  In the process of chasing this with the
1261 	 * hardware people - not sure if it can happen on any illegal
1262 	 * instruction or only on FP instructions, whether there is a
1263 	 * pattern to occurrences etc. -dgibson 31/Mar/2003
1264 	 */
1265 	if (!emulate_math(regs))
1266 		goto bail;
1267 
1268 	/* Try to emulate it if we should. */
1269 	if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
1270 		switch (emulate_instruction(regs)) {
1271 		case 0:
1272 			regs->nip += 4;
1273 			emulate_single_step(regs);
1274 			goto bail;
1275 		case -EFAULT:
1276 			_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
1277 			goto bail;
1278 		}
1279 	}
1280 
1281 sigill:
1282 	if (reason & REASON_PRIVILEGED)
1283 		_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1284 	else
1285 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1286 
1287 bail:
1288 	exception_exit(prev_state);
1289 }
1290 NOKPROBE_SYMBOL(program_check_exception);
1291 
1292 /*
1293  * This occurs when running in hypervisor mode on POWER6 or later
1294  * and an illegal instruction is encountered.
1295  */
1296 void emulation_assist_interrupt(struct pt_regs *regs)
1297 {
1298 	regs->msr |= REASON_ILLEGAL;
1299 	program_check_exception(regs);
1300 }
1301 NOKPROBE_SYMBOL(emulation_assist_interrupt);
1302 
1303 void alignment_exception(struct pt_regs *regs)
1304 {
1305 	enum ctx_state prev_state = exception_enter();
1306 	int sig, code, fixed = 0;
1307 
1308 	/* We restore the interrupt state now */
1309 	if (!arch_irq_disabled_regs(regs))
1310 		local_irq_enable();
1311 
1312 	if (tm_abort_check(regs, TM_CAUSE_ALIGNMENT | TM_CAUSE_PERSISTENT))
1313 		goto bail;
1314 
1315 	/* we don't implement logging of alignment exceptions */
1316 	if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
1317 		fixed = fix_alignment(regs);
1318 
1319 	if (fixed == 1) {
1320 		regs->nip += 4;	/* skip over emulated instruction */
1321 		emulate_single_step(regs);
1322 		goto bail;
1323 	}
1324 
1325 	/* Operand address was bad */
1326 	if (fixed == -EFAULT) {
1327 		sig = SIGSEGV;
1328 		code = SEGV_ACCERR;
1329 	} else {
1330 		sig = SIGBUS;
1331 		code = BUS_ADRALN;
1332 	}
1333 	if (user_mode(regs))
1334 		_exception(sig, regs, code, regs->dar);
1335 	else
1336 		bad_page_fault(regs, regs->dar, sig);
1337 
1338 bail:
1339 	exception_exit(prev_state);
1340 }
1341 
1342 void slb_miss_bad_addr(struct pt_regs *regs)
1343 {
1344 	enum ctx_state prev_state = exception_enter();
1345 
1346 	if (user_mode(regs))
1347 		_exception(SIGSEGV, regs, SEGV_BNDERR, regs->dar);
1348 	else
1349 		bad_page_fault(regs, regs->dar, SIGSEGV);
1350 
1351 	exception_exit(prev_state);
1352 }
1353 
1354 void StackOverflow(struct pt_regs *regs)
1355 {
1356 	printk(KERN_CRIT "Kernel stack overflow in process %p, r1=%lx\n",
1357 	       current, regs->gpr[1]);
1358 	debugger(regs);
1359 	show_regs(regs);
1360 	panic("kernel stack overflow");
1361 }
1362 
1363 void nonrecoverable_exception(struct pt_regs *regs)
1364 {
1365 	printk(KERN_ERR "Non-recoverable exception at PC=%lx MSR=%lx\n",
1366 	       regs->nip, regs->msr);
1367 	debugger(regs);
1368 	die("nonrecoverable exception", regs, SIGKILL);
1369 }
1370 
1371 void kernel_fp_unavailable_exception(struct pt_regs *regs)
1372 {
1373 	enum ctx_state prev_state = exception_enter();
1374 
1375 	printk(KERN_EMERG "Unrecoverable FP Unavailable Exception "
1376 			  "%lx at %lx\n", regs->trap, regs->nip);
1377 	die("Unrecoverable FP Unavailable Exception", regs, SIGABRT);
1378 
1379 	exception_exit(prev_state);
1380 }
1381 
1382 void altivec_unavailable_exception(struct pt_regs *regs)
1383 {
1384 	enum ctx_state prev_state = exception_enter();
1385 
1386 	if (user_mode(regs)) {
1387 		/* A user program has executed an altivec instruction,
1388 		   but this kernel doesn't support altivec. */
1389 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1390 		goto bail;
1391 	}
1392 
1393 	printk(KERN_EMERG "Unrecoverable VMX/Altivec Unavailable Exception "
1394 			"%lx at %lx\n", regs->trap, regs->nip);
1395 	die("Unrecoverable VMX/Altivec Unavailable Exception", regs, SIGABRT);
1396 
1397 bail:
1398 	exception_exit(prev_state);
1399 }
1400 
1401 void vsx_unavailable_exception(struct pt_regs *regs)
1402 {
1403 	if (user_mode(regs)) {
1404 		/* A user program has executed an vsx instruction,
1405 		   but this kernel doesn't support vsx. */
1406 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1407 		return;
1408 	}
1409 
1410 	printk(KERN_EMERG "Unrecoverable VSX Unavailable Exception "
1411 			"%lx at %lx\n", regs->trap, regs->nip);
1412 	die("Unrecoverable VSX Unavailable Exception", regs, SIGABRT);
1413 }
1414 
1415 #ifdef CONFIG_PPC64
1416 static void tm_unavailable(struct pt_regs *regs)
1417 {
1418 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1419 	if (user_mode(regs)) {
1420 		current->thread.load_tm++;
1421 		regs->msr |= MSR_TM;
1422 		tm_enable();
1423 		tm_restore_sprs(&current->thread);
1424 		return;
1425 	}
1426 #endif
1427 	pr_emerg("Unrecoverable TM Unavailable Exception "
1428 			"%lx at %lx\n", regs->trap, regs->nip);
1429 	die("Unrecoverable TM Unavailable Exception", regs, SIGABRT);
1430 }
1431 
1432 void facility_unavailable_exception(struct pt_regs *regs)
1433 {
1434 	static char *facility_strings[] = {
1435 		[FSCR_FP_LG] = "FPU",
1436 		[FSCR_VECVSX_LG] = "VMX/VSX",
1437 		[FSCR_DSCR_LG] = "DSCR",
1438 		[FSCR_PM_LG] = "PMU SPRs",
1439 		[FSCR_BHRB_LG] = "BHRB",
1440 		[FSCR_TM_LG] = "TM",
1441 		[FSCR_EBB_LG] = "EBB",
1442 		[FSCR_TAR_LG] = "TAR",
1443 	};
1444 	char *facility = "unknown";
1445 	u64 value;
1446 	u32 instword, rd;
1447 	u8 status;
1448 	bool hv;
1449 
1450 	hv = (regs->trap == 0xf80);
1451 	if (hv)
1452 		value = mfspr(SPRN_HFSCR);
1453 	else
1454 		value = mfspr(SPRN_FSCR);
1455 
1456 	status = value >> 56;
1457 	if (status == FSCR_DSCR_LG) {
1458 		/*
1459 		 * User is accessing the DSCR register using the problem
1460 		 * state only SPR number (0x03) either through a mfspr or
1461 		 * a mtspr instruction. If it is a write attempt through
1462 		 * a mtspr, then we set the inherit bit. This also allows
1463 		 * the user to write or read the register directly in the
1464 		 * future by setting via the FSCR DSCR bit. But in case it
1465 		 * is a read DSCR attempt through a mfspr instruction, we
1466 		 * just emulate the instruction instead. This code path will
1467 		 * always emulate all the mfspr instructions till the user
1468 		 * has attempted at least one mtspr instruction. This way it
1469 		 * preserves the same behaviour when the user is accessing
1470 		 * the DSCR through privilege level only SPR number (0x11)
1471 		 * which is emulated through illegal instruction exception.
1472 		 * We always leave HFSCR DSCR set.
1473 		 */
1474 		if (get_user(instword, (u32 __user *)(regs->nip))) {
1475 			pr_err("Failed to fetch the user instruction\n");
1476 			return;
1477 		}
1478 
1479 		/* Write into DSCR (mtspr 0x03, RS) */
1480 		if ((instword & PPC_INST_MTSPR_DSCR_USER_MASK)
1481 				== PPC_INST_MTSPR_DSCR_USER) {
1482 			rd = (instword >> 21) & 0x1f;
1483 			current->thread.dscr = regs->gpr[rd];
1484 			current->thread.dscr_inherit = 1;
1485 			current->thread.fscr |= FSCR_DSCR;
1486 			mtspr(SPRN_FSCR, current->thread.fscr);
1487 		}
1488 
1489 		/* Read from DSCR (mfspr RT, 0x03) */
1490 		if ((instword & PPC_INST_MFSPR_DSCR_USER_MASK)
1491 				== PPC_INST_MFSPR_DSCR_USER) {
1492 			if (emulate_instruction(regs)) {
1493 				pr_err("DSCR based mfspr emulation failed\n");
1494 				return;
1495 			}
1496 			regs->nip += 4;
1497 			emulate_single_step(regs);
1498 		}
1499 		return;
1500 	}
1501 
1502 	if (status == FSCR_TM_LG) {
1503 		/*
1504 		 * If we're here then the hardware is TM aware because it
1505 		 * generated an exception with FSRM_TM set.
1506 		 *
1507 		 * If cpu_has_feature(CPU_FTR_TM) is false, then either firmware
1508 		 * told us not to do TM, or the kernel is not built with TM
1509 		 * support.
1510 		 *
1511 		 * If both of those things are true, then userspace can spam the
1512 		 * console by triggering the printk() below just by continually
1513 		 * doing tbegin (or any TM instruction). So in that case just
1514 		 * send the process a SIGILL immediately.
1515 		 */
1516 		if (!cpu_has_feature(CPU_FTR_TM))
1517 			goto out;
1518 
1519 		tm_unavailable(regs);
1520 		return;
1521 	}
1522 
1523 	if ((hv || status >= 2) &&
1524 	    (status < ARRAY_SIZE(facility_strings)) &&
1525 	    facility_strings[status])
1526 		facility = facility_strings[status];
1527 
1528 	/* We restore the interrupt state now */
1529 	if (!arch_irq_disabled_regs(regs))
1530 		local_irq_enable();
1531 
1532 	pr_err_ratelimited("%sFacility '%s' unavailable (%d), exception at 0x%lx, MSR=%lx\n",
1533 		hv ? "Hypervisor " : "", facility, status, regs->nip, regs->msr);
1534 
1535 out:
1536 	if (user_mode(regs)) {
1537 		_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1538 		return;
1539 	}
1540 
1541 	die("Unexpected facility unavailable exception", regs, SIGABRT);
1542 }
1543 #endif
1544 
1545 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1546 
1547 void fp_unavailable_tm(struct pt_regs *regs)
1548 {
1549 	/* Note:  This does not handle any kind of FP laziness. */
1550 
1551 	TM_DEBUG("FP Unavailable trap whilst transactional at 0x%lx, MSR=%lx\n",
1552 		 regs->nip, regs->msr);
1553 
1554         /* We can only have got here if the task started using FP after
1555          * beginning the transaction.  So, the transactional regs are just a
1556          * copy of the checkpointed ones.  But, we still need to recheckpoint
1557          * as we're enabling FP for the process; it will return, abort the
1558          * transaction, and probably retry but now with FP enabled.  So the
1559          * checkpointed FP registers need to be loaded.
1560 	 */
1561 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
1562 	/* Reclaim didn't save out any FPRs to transact_fprs. */
1563 
1564 	/* Enable FP for the task: */
1565 	regs->msr |= (MSR_FP | current->thread.fpexc_mode);
1566 
1567 	/* This loads and recheckpoints the FP registers from
1568 	 * thread.fpr[].  They will remain in registers after the
1569 	 * checkpoint so we don't need to reload them after.
1570 	 * If VMX is in use, the VRs now hold checkpointed values,
1571 	 * so we don't want to load the VRs from the thread_struct.
1572 	 */
1573 	tm_recheckpoint(&current->thread, MSR_FP);
1574 
1575 	/* If VMX is in use, get the transactional values back */
1576 	if (regs->msr & MSR_VEC) {
1577 		msr_check_and_set(MSR_VEC);
1578 		load_vr_state(&current->thread.vr_state);
1579 		/* At this point all the VSX state is loaded, so enable it */
1580 		regs->msr |= MSR_VSX;
1581 	}
1582 }
1583 
1584 void altivec_unavailable_tm(struct pt_regs *regs)
1585 {
1586 	/* See the comments in fp_unavailable_tm().  This function operates
1587 	 * the same way.
1588 	 */
1589 
1590 	TM_DEBUG("Vector Unavailable trap whilst transactional at 0x%lx,"
1591 		 "MSR=%lx\n",
1592 		 regs->nip, regs->msr);
1593 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
1594 	regs->msr |= MSR_VEC;
1595 	tm_recheckpoint(&current->thread, MSR_VEC);
1596 	current->thread.used_vr = 1;
1597 
1598 	if (regs->msr & MSR_FP) {
1599 		msr_check_and_set(MSR_FP);
1600 		load_fp_state(&current->thread.fp_state);
1601 		regs->msr |= MSR_VSX;
1602 	}
1603 }
1604 
1605 void vsx_unavailable_tm(struct pt_regs *regs)
1606 {
1607 	unsigned long orig_msr = regs->msr;
1608 
1609 	/* See the comments in fp_unavailable_tm().  This works similarly,
1610 	 * though we're loading both FP and VEC registers in here.
1611 	 *
1612 	 * If FP isn't in use, load FP regs.  If VEC isn't in use, load VEC
1613 	 * regs.  Either way, set MSR_VSX.
1614 	 */
1615 
1616 	TM_DEBUG("VSX Unavailable trap whilst transactional at 0x%lx,"
1617 		 "MSR=%lx\n",
1618 		 regs->nip, regs->msr);
1619 
1620 	current->thread.used_vsr = 1;
1621 
1622 	/* If FP and VMX are already loaded, we have all the state we need */
1623 	if ((orig_msr & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC)) {
1624 		regs->msr |= MSR_VSX;
1625 		return;
1626 	}
1627 
1628 	/* This reclaims FP and/or VR regs if they're already enabled */
1629 	tm_reclaim_current(TM_CAUSE_FAC_UNAV);
1630 
1631 	regs->msr |= MSR_VEC | MSR_FP | current->thread.fpexc_mode |
1632 		MSR_VSX;
1633 
1634 	/* This loads & recheckpoints FP and VRs; but we have
1635 	 * to be sure not to overwrite previously-valid state.
1636 	 */
1637 	tm_recheckpoint(&current->thread, regs->msr & ~orig_msr);
1638 
1639 	msr_check_and_set(orig_msr & (MSR_FP | MSR_VEC));
1640 
1641 	if (orig_msr & MSR_FP)
1642 		load_fp_state(&current->thread.fp_state);
1643 	if (orig_msr & MSR_VEC)
1644 		load_vr_state(&current->thread.vr_state);
1645 }
1646 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
1647 
1648 void performance_monitor_exception(struct pt_regs *regs)
1649 {
1650 	__this_cpu_inc(irq_stat.pmu_irqs);
1651 
1652 	perf_irq(regs);
1653 }
1654 
1655 #ifdef CONFIG_8xx
1656 void SoftwareEmulation(struct pt_regs *regs)
1657 {
1658 	CHECK_FULL_REGS(regs);
1659 
1660 	if (!user_mode(regs)) {
1661 		debugger(regs);
1662 		die("Kernel Mode Unimplemented Instruction or SW FPU Emulation",
1663 			regs, SIGFPE);
1664 	}
1665 
1666 	if (!emulate_math(regs))
1667 		return;
1668 
1669 	_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
1670 }
1671 #endif /* CONFIG_8xx */
1672 
1673 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1674 static void handle_debug(struct pt_regs *regs, unsigned long debug_status)
1675 {
1676 	int changed = 0;
1677 	/*
1678 	 * Determine the cause of the debug event, clear the
1679 	 * event flags and send a trap to the handler. Torez
1680 	 */
1681 	if (debug_status & (DBSR_DAC1R | DBSR_DAC1W)) {
1682 		dbcr_dac(current) &= ~(DBCR_DAC1R | DBCR_DAC1W);
1683 #ifdef CONFIG_PPC_ADV_DEBUG_DAC_RANGE
1684 		current->thread.debug.dbcr2 &= ~DBCR2_DAC12MODE;
1685 #endif
1686 		do_send_trap(regs, mfspr(SPRN_DAC1), debug_status, TRAP_HWBKPT,
1687 			     5);
1688 		changed |= 0x01;
1689 	}  else if (debug_status & (DBSR_DAC2R | DBSR_DAC2W)) {
1690 		dbcr_dac(current) &= ~(DBCR_DAC2R | DBCR_DAC2W);
1691 		do_send_trap(regs, mfspr(SPRN_DAC2), debug_status, TRAP_HWBKPT,
1692 			     6);
1693 		changed |= 0x01;
1694 	}  else if (debug_status & DBSR_IAC1) {
1695 		current->thread.debug.dbcr0 &= ~DBCR0_IAC1;
1696 		dbcr_iac_range(current) &= ~DBCR_IAC12MODE;
1697 		do_send_trap(regs, mfspr(SPRN_IAC1), debug_status, TRAP_HWBKPT,
1698 			     1);
1699 		changed |= 0x01;
1700 	}  else if (debug_status & DBSR_IAC2) {
1701 		current->thread.debug.dbcr0 &= ~DBCR0_IAC2;
1702 		do_send_trap(regs, mfspr(SPRN_IAC2), debug_status, TRAP_HWBKPT,
1703 			     2);
1704 		changed |= 0x01;
1705 	}  else if (debug_status & DBSR_IAC3) {
1706 		current->thread.debug.dbcr0 &= ~DBCR0_IAC3;
1707 		dbcr_iac_range(current) &= ~DBCR_IAC34MODE;
1708 		do_send_trap(regs, mfspr(SPRN_IAC3), debug_status, TRAP_HWBKPT,
1709 			     3);
1710 		changed |= 0x01;
1711 	}  else if (debug_status & DBSR_IAC4) {
1712 		current->thread.debug.dbcr0 &= ~DBCR0_IAC4;
1713 		do_send_trap(regs, mfspr(SPRN_IAC4), debug_status, TRAP_HWBKPT,
1714 			     4);
1715 		changed |= 0x01;
1716 	}
1717 	/*
1718 	 * At the point this routine was called, the MSR(DE) was turned off.
1719 	 * Check all other debug flags and see if that bit needs to be turned
1720 	 * back on or not.
1721 	 */
1722 	if (DBCR_ACTIVE_EVENTS(current->thread.debug.dbcr0,
1723 			       current->thread.debug.dbcr1))
1724 		regs->msr |= MSR_DE;
1725 	else
1726 		/* Make sure the IDM flag is off */
1727 		current->thread.debug.dbcr0 &= ~DBCR0_IDM;
1728 
1729 	if (changed & 0x01)
1730 		mtspr(SPRN_DBCR0, current->thread.debug.dbcr0);
1731 }
1732 
1733 void DebugException(struct pt_regs *regs, unsigned long debug_status)
1734 {
1735 	current->thread.debug.dbsr = debug_status;
1736 
1737 	/* Hack alert: On BookE, Branch Taken stops on the branch itself, while
1738 	 * on server, it stops on the target of the branch. In order to simulate
1739 	 * the server behaviour, we thus restart right away with a single step
1740 	 * instead of stopping here when hitting a BT
1741 	 */
1742 	if (debug_status & DBSR_BT) {
1743 		regs->msr &= ~MSR_DE;
1744 
1745 		/* Disable BT */
1746 		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_BT);
1747 		/* Clear the BT event */
1748 		mtspr(SPRN_DBSR, DBSR_BT);
1749 
1750 		/* Do the single step trick only when coming from userspace */
1751 		if (user_mode(regs)) {
1752 			current->thread.debug.dbcr0 &= ~DBCR0_BT;
1753 			current->thread.debug.dbcr0 |= DBCR0_IDM | DBCR0_IC;
1754 			regs->msr |= MSR_DE;
1755 			return;
1756 		}
1757 
1758 		if (kprobe_post_handler(regs))
1759 			return;
1760 
1761 		if (notify_die(DIE_SSTEP, "block_step", regs, 5,
1762 			       5, SIGTRAP) == NOTIFY_STOP) {
1763 			return;
1764 		}
1765 		if (debugger_sstep(regs))
1766 			return;
1767 	} else if (debug_status & DBSR_IC) { 	/* Instruction complete */
1768 		regs->msr &= ~MSR_DE;
1769 
1770 		/* Disable instruction completion */
1771 		mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~DBCR0_IC);
1772 		/* Clear the instruction completion event */
1773 		mtspr(SPRN_DBSR, DBSR_IC);
1774 
1775 		if (kprobe_post_handler(regs))
1776 			return;
1777 
1778 		if (notify_die(DIE_SSTEP, "single_step", regs, 5,
1779 			       5, SIGTRAP) == NOTIFY_STOP) {
1780 			return;
1781 		}
1782 
1783 		if (debugger_sstep(regs))
1784 			return;
1785 
1786 		if (user_mode(regs)) {
1787 			current->thread.debug.dbcr0 &= ~DBCR0_IC;
1788 			if (DBCR_ACTIVE_EVENTS(current->thread.debug.dbcr0,
1789 					       current->thread.debug.dbcr1))
1790 				regs->msr |= MSR_DE;
1791 			else
1792 				/* Make sure the IDM bit is off */
1793 				current->thread.debug.dbcr0 &= ~DBCR0_IDM;
1794 		}
1795 
1796 		_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
1797 	} else
1798 		handle_debug(regs, debug_status);
1799 }
1800 NOKPROBE_SYMBOL(DebugException);
1801 #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
1802 
1803 #if !defined(CONFIG_TAU_INT)
1804 void TAUException(struct pt_regs *regs)
1805 {
1806 	printk("TAU trap at PC: %lx, MSR: %lx, vector=%lx    %s\n",
1807 	       regs->nip, regs->msr, regs->trap, print_tainted());
1808 }
1809 #endif /* CONFIG_INT_TAU */
1810 
1811 #ifdef CONFIG_ALTIVEC
1812 void altivec_assist_exception(struct pt_regs *regs)
1813 {
1814 	int err;
1815 
1816 	if (!user_mode(regs)) {
1817 		printk(KERN_EMERG "VMX/Altivec assist exception in kernel mode"
1818 		       " at %lx\n", regs->nip);
1819 		die("Kernel VMX/Altivec assist exception", regs, SIGILL);
1820 	}
1821 
1822 	flush_altivec_to_thread(current);
1823 
1824 	PPC_WARN_EMULATED(altivec, regs);
1825 	err = emulate_altivec(regs);
1826 	if (err == 0) {
1827 		regs->nip += 4;		/* skip emulated instruction */
1828 		emulate_single_step(regs);
1829 		return;
1830 	}
1831 
1832 	if (err == -EFAULT) {
1833 		/* got an error reading the instruction */
1834 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1835 	} else {
1836 		/* didn't recognize the instruction */
1837 		/* XXX quick hack for now: set the non-Java bit in the VSCR */
1838 		printk_ratelimited(KERN_ERR "Unrecognized altivec instruction "
1839 				   "in %s at %lx\n", current->comm, regs->nip);
1840 		current->thread.vr_state.vscr.u[3] |= 0x10000;
1841 	}
1842 }
1843 #endif /* CONFIG_ALTIVEC */
1844 
1845 #ifdef CONFIG_FSL_BOOKE
1846 void CacheLockingException(struct pt_regs *regs, unsigned long address,
1847 			   unsigned long error_code)
1848 {
1849 	/* We treat cache locking instructions from the user
1850 	 * as priv ops, in the future we could try to do
1851 	 * something smarter
1852 	 */
1853 	if (error_code & (ESR_DLK|ESR_ILK))
1854 		_exception(SIGILL, regs, ILL_PRVOPC, regs->nip);
1855 	return;
1856 }
1857 #endif /* CONFIG_FSL_BOOKE */
1858 
1859 #ifdef CONFIG_SPE
1860 void SPEFloatingPointException(struct pt_regs *regs)
1861 {
1862 	extern int do_spe_mathemu(struct pt_regs *regs);
1863 	unsigned long spefscr;
1864 	int fpexc_mode;
1865 	int code = 0;
1866 	int err;
1867 
1868 	flush_spe_to_thread(current);
1869 
1870 	spefscr = current->thread.spefscr;
1871 	fpexc_mode = current->thread.fpexc_mode;
1872 
1873 	if ((spefscr & SPEFSCR_FOVF) && (fpexc_mode & PR_FP_EXC_OVF)) {
1874 		code = FPE_FLTOVF;
1875 	}
1876 	else if ((spefscr & SPEFSCR_FUNF) && (fpexc_mode & PR_FP_EXC_UND)) {
1877 		code = FPE_FLTUND;
1878 	}
1879 	else if ((spefscr & SPEFSCR_FDBZ) && (fpexc_mode & PR_FP_EXC_DIV))
1880 		code = FPE_FLTDIV;
1881 	else if ((spefscr & SPEFSCR_FINV) && (fpexc_mode & PR_FP_EXC_INV)) {
1882 		code = FPE_FLTINV;
1883 	}
1884 	else if ((spefscr & (SPEFSCR_FG | SPEFSCR_FX)) && (fpexc_mode & PR_FP_EXC_RES))
1885 		code = FPE_FLTRES;
1886 
1887 	err = do_spe_mathemu(regs);
1888 	if (err == 0) {
1889 		regs->nip += 4;		/* skip emulated instruction */
1890 		emulate_single_step(regs);
1891 		return;
1892 	}
1893 
1894 	if (err == -EFAULT) {
1895 		/* got an error reading the instruction */
1896 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1897 	} else if (err == -EINVAL) {
1898 		/* didn't recognize the instruction */
1899 		printk(KERN_ERR "unrecognized spe instruction "
1900 		       "in %s at %lx\n", current->comm, regs->nip);
1901 	} else {
1902 		_exception(SIGFPE, regs, code, regs->nip);
1903 	}
1904 
1905 	return;
1906 }
1907 
1908 void SPEFloatingPointRoundException(struct pt_regs *regs)
1909 {
1910 	extern int speround_handler(struct pt_regs *regs);
1911 	int err;
1912 
1913 	preempt_disable();
1914 	if (regs->msr & MSR_SPE)
1915 		giveup_spe(current);
1916 	preempt_enable();
1917 
1918 	regs->nip -= 4;
1919 	err = speround_handler(regs);
1920 	if (err == 0) {
1921 		regs->nip += 4;		/* skip emulated instruction */
1922 		emulate_single_step(regs);
1923 		return;
1924 	}
1925 
1926 	if (err == -EFAULT) {
1927 		/* got an error reading the instruction */
1928 		_exception(SIGSEGV, regs, SEGV_ACCERR, regs->nip);
1929 	} else if (err == -EINVAL) {
1930 		/* didn't recognize the instruction */
1931 		printk(KERN_ERR "unrecognized spe instruction "
1932 		       "in %s at %lx\n", current->comm, regs->nip);
1933 	} else {
1934 		_exception(SIGFPE, regs, 0, regs->nip);
1935 		return;
1936 	}
1937 }
1938 #endif
1939 
1940 /*
1941  * We enter here if we get an unrecoverable exception, that is, one
1942  * that happened at a point where the RI (recoverable interrupt) bit
1943  * in the MSR is 0.  This indicates that SRR0/1 are live, and that
1944  * we therefore lost state by taking this exception.
1945  */
1946 void unrecoverable_exception(struct pt_regs *regs)
1947 {
1948 	printk(KERN_EMERG "Unrecoverable exception %lx at %lx\n",
1949 	       regs->trap, regs->nip);
1950 	die("Unrecoverable exception", regs, SIGABRT);
1951 }
1952 
1953 #if defined(CONFIG_BOOKE_WDT) || defined(CONFIG_40x)
1954 /*
1955  * Default handler for a Watchdog exception,
1956  * spins until a reboot occurs
1957  */
1958 void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
1959 {
1960 	/* Generic WatchdogHandler, implement your own */
1961 	mtspr(SPRN_TCR, mfspr(SPRN_TCR)&(~TCR_WIE));
1962 	return;
1963 }
1964 
1965 void WatchdogException(struct pt_regs *regs)
1966 {
1967 	printk (KERN_EMERG "PowerPC Book-E Watchdog Exception\n");
1968 	WatchdogHandler(regs);
1969 }
1970 #endif
1971 
1972 /*
1973  * We enter here if we discover during exception entry that we are
1974  * running in supervisor mode with a userspace value in the stack pointer.
1975  */
1976 void kernel_bad_stack(struct pt_regs *regs)
1977 {
1978 	printk(KERN_EMERG "Bad kernel stack pointer %lx at %lx\n",
1979 	       regs->gpr[1], regs->nip);
1980 	die("Bad kernel stack pointer", regs, SIGABRT);
1981 }
1982 
1983 void __init trap_init(void)
1984 {
1985 }
1986 
1987 
1988 #ifdef CONFIG_PPC_EMULATED_STATS
1989 
1990 #define WARN_EMULATED_SETUP(type)	.type = { .name = #type }
1991 
1992 struct ppc_emulated ppc_emulated = {
1993 #ifdef CONFIG_ALTIVEC
1994 	WARN_EMULATED_SETUP(altivec),
1995 #endif
1996 	WARN_EMULATED_SETUP(dcba),
1997 	WARN_EMULATED_SETUP(dcbz),
1998 	WARN_EMULATED_SETUP(fp_pair),
1999 	WARN_EMULATED_SETUP(isel),
2000 	WARN_EMULATED_SETUP(mcrxr),
2001 	WARN_EMULATED_SETUP(mfpvr),
2002 	WARN_EMULATED_SETUP(multiple),
2003 	WARN_EMULATED_SETUP(popcntb),
2004 	WARN_EMULATED_SETUP(spe),
2005 	WARN_EMULATED_SETUP(string),
2006 	WARN_EMULATED_SETUP(sync),
2007 	WARN_EMULATED_SETUP(unaligned),
2008 #ifdef CONFIG_MATH_EMULATION
2009 	WARN_EMULATED_SETUP(math),
2010 #endif
2011 #ifdef CONFIG_VSX
2012 	WARN_EMULATED_SETUP(vsx),
2013 #endif
2014 #ifdef CONFIG_PPC64
2015 	WARN_EMULATED_SETUP(mfdscr),
2016 	WARN_EMULATED_SETUP(mtdscr),
2017 	WARN_EMULATED_SETUP(lq_stq),
2018 #endif
2019 };
2020 
2021 u32 ppc_warn_emulated;
2022 
2023 void ppc_warn_emulated_print(const char *type)
2024 {
2025 	pr_warn_ratelimited("%s used emulated %s instruction\n", current->comm,
2026 			    type);
2027 }
2028 
2029 static int __init ppc_warn_emulated_init(void)
2030 {
2031 	struct dentry *dir, *d;
2032 	unsigned int i;
2033 	struct ppc_emulated_entry *entries = (void *)&ppc_emulated;
2034 
2035 	if (!powerpc_debugfs_root)
2036 		return -ENODEV;
2037 
2038 	dir = debugfs_create_dir("emulated_instructions",
2039 				 powerpc_debugfs_root);
2040 	if (!dir)
2041 		return -ENOMEM;
2042 
2043 	d = debugfs_create_u32("do_warn", S_IRUGO | S_IWUSR, dir,
2044 			       &ppc_warn_emulated);
2045 	if (!d)
2046 		goto fail;
2047 
2048 	for (i = 0; i < sizeof(ppc_emulated)/sizeof(*entries); i++) {
2049 		d = debugfs_create_u32(entries[i].name, S_IRUGO | S_IWUSR, dir,
2050 				       (u32 *)&entries[i].val.counter);
2051 		if (!d)
2052 			goto fail;
2053 	}
2054 
2055 	return 0;
2056 
2057 fail:
2058 	debugfs_remove_recursive(dir);
2059 	return -ENOMEM;
2060 }
2061 
2062 device_initcall(ppc_warn_emulated_init);
2063 
2064 #endif /* CONFIG_PPC_EMULATED_STATS */
2065