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xen: cleancache shim to Xen Transcendent Memory
[linux-2.6/next.git] / arch / ia64 / kernel / traps.c
blobfd80e70018a959ebffdf860c962cf0ff062cc4f5
1 /*
2 * Architecture-specific trap handling.
3 *
4 * Copyright (C) 1998-2003 Hewlett-Packard Co
5 * David Mosberger-Tang <davidm@hpl.hp.com>
6 *
7 * 05/12/00 grao <goutham.rao@intel.com> : added isr in siginfo for SIGFPE
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/sched.h>
13 #include <linux/tty.h>
14 #include <linux/vt_kern.h> /* For unblank_screen() */
15 #include <linux/module.h> /* for EXPORT_SYMBOL */
16 #include <linux/hardirq.h>
17 #include <linux/kprobes.h>
18 #include <linux/delay.h> /* for ssleep() */
19 #include <linux/kdebug.h>
20
21 #include <asm/fpswa.h>
22 #include <asm/intrinsics.h>
23 #include <asm/processor.h>
24 #include <asm/uaccess.h>
25
26 fpswa_interface_t *fpswa_interface;
27 EXPORT_SYMBOL(fpswa_interface);
28
29 void __init
30 trap_init (void)
31 {
32 if (ia64_boot_param->fpswa)
33 /* FPSWA fixup: make the interface pointer a kernel virtual address: */
34 fpswa_interface = __va(ia64_boot_param->fpswa);
35 }
36
37 int
38 die (const char *str, struct pt_regs *regs, long err)
39 {
40 static struct {
41 spinlock_t lock;
42 u32 lock_owner;
43 int lock_owner_depth;
44 } die = {
45 .lock = __SPIN_LOCK_UNLOCKED(die.lock),
46 .lock_owner = -1,
47 .lock_owner_depth = 0
48 };
49 static int die_counter;
50 int cpu = get_cpu();
51
52 if (die.lock_owner != cpu) {
53 console_verbose();
54 spin_lock_irq(&die.lock);
55 die.lock_owner = cpu;
56 die.lock_owner_depth = 0;
57 bust_spinlocks(1);
58 }
59 put_cpu();
60
61 if (++die.lock_owner_depth < 3) {
62 printk("%s[%d]: %s %ld [%d]\n",
63 current->comm, task_pid_nr(current), str, err, ++die_counter);
64 if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV)
65 != NOTIFY_STOP)
66 show_regs(regs);
67 else
68 regs = NULL;
69 } else
70 printk(KERN_ERR "Recursive die() failure, output suppressed\n");
71
72 bust_spinlocks(0);
73 die.lock_owner = -1;
74 add_taint(TAINT_DIE);
75 spin_unlock_irq(&die.lock);
76
77 if (!regs)
78 return 1;
79
80 if (panic_on_oops)
81 panic("Fatal exception");
82
83 do_exit(SIGSEGV);
84 return 0;
85 }
86
87 int
88 die_if_kernel (char *str, struct pt_regs *regs, long err)
89 {
90 if (!user_mode(regs))
91 return die(str, regs, err);
92 return 0;
93 }
94
95 void
96 __kprobes ia64_bad_break (unsigned long break_num, struct pt_regs *regs)
97 {
98 siginfo_t siginfo;
99 int sig, code;
100
101 /* SIGILL, SIGFPE, SIGSEGV, and SIGBUS want these field initialized: */
102 siginfo.si_addr = (void __user *) (regs->cr_iip + ia64_psr(regs)->ri);
103 siginfo.si_imm = break_num;
104 siginfo.si_flags = 0; /* clear __ISR_VALID */
105 siginfo.si_isr = 0;
106
107 switch (break_num) {
108 case 0: /* unknown error (used by GCC for __builtin_abort()) */
109 if (notify_die(DIE_BREAK, "break 0", regs, break_num, TRAP_BRKPT, SIGTRAP)
110 == NOTIFY_STOP)
111 return;
112 if (die_if_kernel("bugcheck!", regs, break_num))
113 return;
114 sig = SIGILL; code = ILL_ILLOPC;
115 break;
116
117 case 1: /* integer divide by zero */
118 sig = SIGFPE; code = FPE_INTDIV;
119 break;
120
121 case 2: /* integer overflow */
122 sig = SIGFPE; code = FPE_INTOVF;
123 break;
124
125 case 3: /* range check/bounds check */
126 sig = SIGFPE; code = FPE_FLTSUB;
127 break;
128
129 case 4: /* null pointer dereference */
130 sig = SIGSEGV; code = SEGV_MAPERR;
131 break;
132
133 case 5: /* misaligned data */
134 sig = SIGSEGV; code = BUS_ADRALN;
135 break;
136
137 case 6: /* decimal overflow */
138 sig = SIGFPE; code = __FPE_DECOVF;
139 break;
140
141 case 7: /* decimal divide by zero */
142 sig = SIGFPE; code = __FPE_DECDIV;
143 break;
144
145 case 8: /* packed decimal error */
146 sig = SIGFPE; code = __FPE_DECERR;
147 break;
148
149 case 9: /* invalid ASCII digit */
150 sig = SIGFPE; code = __FPE_INVASC;
151 break;
152
153 case 10: /* invalid decimal digit */
154 sig = SIGFPE; code = __FPE_INVDEC;
155 break;
156
157 case 11: /* paragraph stack overflow */
158 sig = SIGSEGV; code = __SEGV_PSTKOVF;
159 break;
160
161 case 0x3f000 ... 0x3ffff: /* bundle-update in progress */
162 sig = SIGILL; code = __ILL_BNDMOD;
163 break;
164
165 default:
166 if ((break_num < 0x40000 || break_num > 0x100000)
167 && die_if_kernel("Bad break", regs, break_num))
168 return;
169
170 if (break_num < 0x80000) {
171 sig = SIGILL; code = __ILL_BREAK;
172 } else {
173 if (notify_die(DIE_BREAK, "bad break", regs, break_num, TRAP_BRKPT, SIGTRAP)
174 == NOTIFY_STOP)
175 return;
176 sig = SIGTRAP; code = TRAP_BRKPT;
177 }
178 }
179 siginfo.si_signo = sig;
180 siginfo.si_errno = 0;
181 siginfo.si_code = code;
182 force_sig_info(sig, &siginfo, current);
183 }
184
185 /*
186 * disabled_fph_fault() is called when a user-level process attempts to access f32..f127
187 * and it doesn't own the fp-high register partition. When this happens, we save the
188 * current fph partition in the task_struct of the fpu-owner (if necessary) and then load
189 * the fp-high partition of the current task (if necessary). Note that the kernel has
190 * access to fph by the time we get here, as the IVT's "Disabled FP-Register" handler takes
191 * care of clearing psr.dfh.
192 */
193 static inline void
194 disabled_fph_fault (struct pt_regs *regs)
195 {
196 struct ia64_psr *psr = ia64_psr(regs);
197
198 /* first, grant user-level access to fph partition: */
199 psr->dfh = 0;
200
201 /*
202 * Make sure that no other task gets in on this processor
203 * while we're claiming the FPU
204 */
205 preempt_disable();
206 #ifndef CONFIG_SMP
207 {
208 struct task_struct *fpu_owner
209 = (struct task_struct *)ia64_get_kr(IA64_KR_FPU_OWNER);
210
211 if (ia64_is_local_fpu_owner(current)) {
212 preempt_enable_no_resched();
213 return;
214 }
215
216 if (fpu_owner)
217 ia64_flush_fph(fpu_owner);
218 }
219 #endif /* !CONFIG_SMP */
220 ia64_set_local_fpu_owner(current);
221 if ((current->thread.flags & IA64_THREAD_FPH_VALID) != 0) {
222 __ia64_load_fpu(current->thread.fph);
223 psr->mfh = 0;
224 } else {
225 __ia64_init_fpu();
226 /*
227 * Set mfh because the state in thread.fph does not match the state in
228 * the fph partition.
229 */
230 psr->mfh = 1;
231 }
232 preempt_enable_no_resched();
233 }
234
235 static inline int
236 fp_emulate (int fp_fault, void *bundle, long *ipsr, long *fpsr, long *isr, long *pr, long *ifs,
237 struct pt_regs *regs)
238 {
239 fp_state_t fp_state;
240 fpswa_ret_t ret;
241
242 if (!fpswa_interface)
243 return -1;
244
245 memset(&fp_state, 0, sizeof(fp_state_t));
246
247 /*
248 * compute fp_state. only FP registers f6 - f11 are used by the
249 * kernel, so set those bits in the mask and set the low volatile
250 * pointer to point to these registers.
251 */
252 fp_state.bitmask_low64 = 0xfc0; /* bit6..bit11 */
253
254 fp_state.fp_state_low_volatile = (fp_state_low_volatile_t *) &regs->f6;
255 /*
256 * unsigned long (*EFI_FPSWA) (
257 * unsigned long trap_type,
258 * void *Bundle,
259 * unsigned long *pipsr,
260 * unsigned long *pfsr,
261 * unsigned long *pisr,
262 * unsigned long *ppreds,
263 * unsigned long *pifs,
264 * void *fp_state);
265 */
266 ret = (*fpswa_interface->fpswa)((unsigned long) fp_fault, bundle,
267 (unsigned long *) ipsr, (unsigned long *) fpsr,
268 (unsigned long *) isr, (unsigned long *) pr,
269 (unsigned long *) ifs, &fp_state);
270
271 return ret.status;
272 }
273
274 struct fpu_swa_msg {
275 unsigned long count;
276 unsigned long time;
277 };
278 static DEFINE_PER_CPU(struct fpu_swa_msg, cpulast);
279 DECLARE_PER_CPU(struct fpu_swa_msg, cpulast);
280 static struct fpu_swa_msg last __cacheline_aligned;
281
282
283 /*
284 * Handle floating-point assist faults and traps.
285 */
286 static int
287 handle_fpu_swa (int fp_fault, struct pt_regs *regs, unsigned long isr)
288 {
289 long exception, bundle[2];
290 unsigned long fault_ip;
291 struct siginfo siginfo;
292
293 fault_ip = regs->cr_iip;
294 if (!fp_fault && (ia64_psr(regs)->ri == 0))
295 fault_ip -= 16;
296 if (copy_from_user(bundle, (void __user *) fault_ip, sizeof(bundle)))
297 return -1;
298
299 if (!(current->thread.flags & IA64_THREAD_FPEMU_NOPRINT)) {
300 unsigned long count, current_jiffies = jiffies;
301 struct fpu_swa_msg *cp = &__get_cpu_var(cpulast);
302
303 if (unlikely(current_jiffies > cp->time))
304 cp->count = 0;
305 if (unlikely(cp->count < 5)) {
306 cp->count++;
307 cp->time = current_jiffies + 5 * HZ;
308
309 /* minimize races by grabbing a copy of count BEFORE checking last.time. */
310 count = last.count;
311 barrier();
312
313 /*
314 * Lower 4 bits are used as a count. Upper bits are a sequence
315 * number that is updated when count is reset. The cmpxchg will
316 * fail is seqno has changed. This minimizes mutiple cpus
317 * resetting the count.
318 */
319 if (current_jiffies > last.time)
320 (void) cmpxchg_acq(&last.count, count, 16 + (count & ~15));
321
322 /* used fetchadd to atomically update the count */
323 if ((last.count & 15) < 5 && (ia64_fetchadd(1, &last.count, acq) & 15) < 5) {
324 last.time = current_jiffies + 5 * HZ;
325 printk(KERN_WARNING
326 "%s(%d): floating-point assist fault at ip %016lx, isr %016lx\n",
327 current->comm, task_pid_nr(current), regs->cr_iip + ia64_psr(regs)->ri, isr);
328 }
329 }
330 }
331
332 exception = fp_emulate(fp_fault, bundle, &regs->cr_ipsr, &regs->ar_fpsr, &isr, &regs->pr,
333 &regs->cr_ifs, regs);
334 if (fp_fault) {
335 if (exception == 0) {
336 /* emulation was successful */
337 ia64_increment_ip(regs);
338 } else if (exception == -1) {
339 printk(KERN_ERR "handle_fpu_swa: fp_emulate() returned -1\n");
340 return -1;
341 } else {
342 /* is next instruction a trap? */
343 if (exception & 2) {
344 ia64_increment_ip(regs);
345 }
346 siginfo.si_signo = SIGFPE;
347 siginfo.si_errno = 0;
348 siginfo.si_code = __SI_FAULT; /* default code */
349 siginfo.si_addr = (void __user *) (regs->cr_iip + ia64_psr(regs)->ri);
350 if (isr & 0x11) {
351 siginfo.si_code = FPE_FLTINV;
352 } else if (isr & 0x22) {
353 /* denormal operand gets the same si_code as underflow
354 * see arch/i386/kernel/traps.c:math_error() */
355 siginfo.si_code = FPE_FLTUND;
356 } else if (isr & 0x44) {
357 siginfo.si_code = FPE_FLTDIV;
358 }
359 siginfo.si_isr = isr;
360 siginfo.si_flags = __ISR_VALID;
361 siginfo.si_imm = 0;
362 force_sig_info(SIGFPE, &siginfo, current);
363 }
364 } else {
365 if (exception == -1) {
366 printk(KERN_ERR "handle_fpu_swa: fp_emulate() returned -1\n");
367 return -1;
368 } else if (exception != 0) {
369 /* raise exception */
370 siginfo.si_signo = SIGFPE;
371 siginfo.si_errno = 0;
372 siginfo.si_code = __SI_FAULT; /* default code */
373 siginfo.si_addr = (void __user *) (regs->cr_iip + ia64_psr(regs)->ri);
374 if (isr & 0x880) {
375 siginfo.si_code = FPE_FLTOVF;
376 } else if (isr & 0x1100) {
377 siginfo.si_code = FPE_FLTUND;
378 } else if (isr & 0x2200) {
379 siginfo.si_code = FPE_FLTRES;
380 }
381 siginfo.si_isr = isr;
382 siginfo.si_flags = __ISR_VALID;
383 siginfo.si_imm = 0;
384 force_sig_info(SIGFPE, &siginfo, current);
385 }
386 }
387 return 0;
388 }
389
390 struct illegal_op_return {
391 unsigned long fkt, arg1, arg2, arg3;
392 };
393
394 struct illegal_op_return
395 ia64_illegal_op_fault (unsigned long ec, long arg1, long arg2, long arg3,
396 long arg4, long arg5, long arg6, long arg7,
397 struct pt_regs regs)
398 {
399 struct illegal_op_return rv;
400 struct siginfo si;
401 char buf[128];
402
403 #ifdef CONFIG_IA64_BRL_EMU
404 {
405 extern struct illegal_op_return ia64_emulate_brl (struct pt_regs *, unsigned long);
406
407 rv = ia64_emulate_brl(&regs, ec);
408 if (rv.fkt != (unsigned long) -1)
409 return rv;
410 }
411 #endif
412
413 sprintf(buf, "IA-64 Illegal operation fault");
414 rv.fkt = 0;
415 if (die_if_kernel(buf, &regs, 0))
416 return rv;
417
418 memset(&si, 0, sizeof(si));
419 si.si_signo = SIGILL;
420 si.si_code = ILL_ILLOPC;
421 si.si_addr = (void __user *) (regs.cr_iip + ia64_psr(&regs)->ri);
422 force_sig_info(SIGILL, &si, current);
423 return rv;
424 }
425
426 void __kprobes
427 ia64_fault (unsigned long vector, unsigned long isr, unsigned long ifa,
428 unsigned long iim, unsigned long itir, long arg5, long arg6,
429 long arg7, struct pt_regs regs)
430 {
431 unsigned long code, error = isr, iip;
432 struct siginfo siginfo;
433 char buf[128];
434 int result, sig;
435 static const char *reason[] = {
436 "IA-64 Illegal Operation fault",
437 "IA-64 Privileged Operation fault",
438 "IA-64 Privileged Register fault",
439 "IA-64 Reserved Register/Field fault",
440 "Disabled Instruction Set Transition fault",
441 "Unknown fault 5", "Unknown fault 6", "Unknown fault 7", "Illegal Hazard fault",
442 "Unknown fault 9", "Unknown fault 10", "Unknown fault 11", "Unknown fault 12",
443 "Unknown fault 13", "Unknown fault 14", "Unknown fault 15"
444 };
445
446 if ((isr & IA64_ISR_NA) && ((isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH)) {
447 /*
448 * This fault was due to lfetch.fault, set "ed" bit in the psr to cancel
449 * the lfetch.
450 */
451 ia64_psr(&regs)->ed = 1;
452 return;
453 }
454
455 iip = regs.cr_iip + ia64_psr(&regs)->ri;
456
457 switch (vector) {
458 case 24: /* General Exception */
459 code = (isr >> 4) & 0xf;
460 sprintf(buf, "General Exception: %s%s", reason[code],
461 (code == 3) ? ((isr & (1UL << 37))
462 ? " (RSE access)" : " (data access)") : "");
463 if (code == 8) {
464 # ifdef CONFIG_IA64_PRINT_HAZARDS
465 printk("%s[%d]: possible hazard @ ip=%016lx (pr = %016lx)\n",
466 current->comm, task_pid_nr(current),
467 regs.cr_iip + ia64_psr(&regs)->ri, regs.pr);
468 # endif
469 return;
470 }
471 break;
472
473 case 25: /* Disabled FP-Register */
474 if (isr & 2) {
475 disabled_fph_fault(&regs);
476 return;
477 }
478 sprintf(buf, "Disabled FPL fault---not supposed to happen!");
479 break;
480
481 case 26: /* NaT Consumption */
482 if (user_mode(&regs)) {
483 void __user *addr;
484
485 if (((isr >> 4) & 0xf) == 2) {
486 /* NaT page consumption */
487 sig = SIGSEGV;
488 code = SEGV_ACCERR;
489 addr = (void __user *) ifa;
490 } else {
491 /* register NaT consumption */
492 sig = SIGILL;
493 code = ILL_ILLOPN;
494 addr = (void __user *) (regs.cr_iip
495 + ia64_psr(&regs)->ri);
496 }
497 siginfo.si_signo = sig;
498 siginfo.si_code = code;
499 siginfo.si_errno = 0;
500 siginfo.si_addr = addr;
501 siginfo.si_imm = vector;
502 siginfo.si_flags = __ISR_VALID;
503 siginfo.si_isr = isr;
504 force_sig_info(sig, &siginfo, current);
505 return;
506 } else if (ia64_done_with_exception(&regs))
507 return;
508 sprintf(buf, "NaT consumption");
509 break;
510
511 case 31: /* Unsupported Data Reference */
512 if (user_mode(&regs)) {
513 siginfo.si_signo = SIGILL;
514 siginfo.si_code = ILL_ILLOPN;
515 siginfo.si_errno = 0;
516 siginfo.si_addr = (void __user *) iip;
517 siginfo.si_imm = vector;
518 siginfo.si_flags = __ISR_VALID;
519 siginfo.si_isr = isr;
520 force_sig_info(SIGILL, &siginfo, current);
521 return;
522 }
523 sprintf(buf, "Unsupported data reference");
524 break;
525
526 case 29: /* Debug */
527 case 35: /* Taken Branch Trap */
528 case 36: /* Single Step Trap */
529 if (fsys_mode(current, &regs)) {
530 extern char __kernel_syscall_via_break[];
531 /*
532 * Got a trap in fsys-mode: Taken Branch Trap
533 * and Single Step trap need special handling;
534 * Debug trap is ignored (we disable it here
535 * and re-enable it in the lower-privilege trap).
536 */
537 if (unlikely(vector == 29)) {
538 set_thread_flag(TIF_DB_DISABLED);
539 ia64_psr(&regs)->db = 0;
540 ia64_psr(&regs)->lp = 1;
541 return;
542 }
543 /* re-do the system call via break 0x100000: */
544 regs.cr_iip = (unsigned long) __kernel_syscall_via_break;
545 ia64_psr(&regs)->ri = 0;
546 ia64_psr(&regs)->cpl = 3;
547 return;
548 }
549 switch (vector) {
550 case 29:
551 siginfo.si_code = TRAP_HWBKPT;
552 #ifdef CONFIG_ITANIUM
553 /*
554 * Erratum 10 (IFA may contain incorrect address) now has
555 * "NoFix" status. There are no plans for fixing this.
556 */
557 if (ia64_psr(&regs)->is == 0)
558 ifa = regs.cr_iip;
559 #endif
560 break;
561 case 35: siginfo.si_code = TRAP_BRANCH; ifa = 0; break;
562 case 36: siginfo.si_code = TRAP_TRACE; ifa = 0; break;
563 }
564 if (notify_die(DIE_FAULT, "ia64_fault", &regs, vector, siginfo.si_code, SIGTRAP)
565 == NOTIFY_STOP)
566 return;
567 siginfo.si_signo = SIGTRAP;
568 siginfo.si_errno = 0;
569 siginfo.si_addr = (void __user *) ifa;
570 siginfo.si_imm = 0;
571 siginfo.si_flags = __ISR_VALID;
572 siginfo.si_isr = isr;
573 force_sig_info(SIGTRAP, &siginfo, current);
574 return;
575
576 case 32: /* fp fault */
577 case 33: /* fp trap */
578 result = handle_fpu_swa((vector == 32) ? 1 : 0, &regs, isr);
579 if ((result < 0) || (current->thread.flags & IA64_THREAD_FPEMU_SIGFPE)) {
580 siginfo.si_signo = SIGFPE;
581 siginfo.si_errno = 0;
582 siginfo.si_code = FPE_FLTINV;
583 siginfo.si_addr = (void __user *) iip;
584 siginfo.si_flags = __ISR_VALID;
585 siginfo.si_isr = isr;
586 siginfo.si_imm = 0;
587 force_sig_info(SIGFPE, &siginfo, current);
588 }
589 return;
590
591 case 34:
592 if (isr & 0x2) {
593 /* Lower-Privilege Transfer Trap */
594
595 /* If we disabled debug traps during an fsyscall,
596 * re-enable them here.
597 */
598 if (test_thread_flag(TIF_DB_DISABLED)) {
599 clear_thread_flag(TIF_DB_DISABLED);
600 ia64_psr(&regs)->db = 1;
601 }
602
603 /*
604 * Just clear PSR.lp and then return immediately:
605 * all the interesting work (e.g., signal delivery)
606 * is done in the kernel exit path.
607 */
608 ia64_psr(&regs)->lp = 0;
609 return;
610 } else {
611 /* Unimplemented Instr. Address Trap */
612 if (user_mode(&regs)) {
613 siginfo.si_signo = SIGILL;
614 siginfo.si_code = ILL_BADIADDR;
615 siginfo.si_errno = 0;
616 siginfo.si_flags = 0;
617 siginfo.si_isr = 0;
618 siginfo.si_imm = 0;
619 siginfo.si_addr = (void __user *) iip;
620 force_sig_info(SIGILL, &siginfo, current);
621 return;
622 }
623 sprintf(buf, "Unimplemented Instruction Address fault");
624 }
625 break;
626
627 case 45:
628 printk(KERN_ERR "Unexpected IA-32 exception (Trap 45)\n");
629 printk(KERN_ERR " iip - 0x%lx, ifa - 0x%lx, isr - 0x%lx\n",
630 iip, ifa, isr);
631 force_sig(SIGSEGV, current);
632 break;
633
634 case 46:
635 printk(KERN_ERR "Unexpected IA-32 intercept trap (Trap 46)\n");
636 printk(KERN_ERR " iip - 0x%lx, ifa - 0x%lx, isr - 0x%lx, iim - 0x%lx\n",
637 iip, ifa, isr, iim);
638 force_sig(SIGSEGV, current);
639 return;
640
641 case 47:
642 sprintf(buf, "IA-32 Interruption Fault (int 0x%lx)", isr >> 16);
643 break;
644
645 default:
646 sprintf(buf, "Fault %lu", vector);
647 break;
648 }
649 if (!die_if_kernel(buf, &regs, error))
650 force_sig(SIGILL, current);
651 }
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