1/*
2 * Handle unaligned accesses by emulation.
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 1996, 1998, 1999, 2002 by Ralf Baechle
9 * Copyright (C) 1999 Silicon Graphics, Inc.
10 * Copyright (C) 2014 Imagination Technologies Ltd.
11 *
12 * This file contains exception handler for address error exception with the
13 * special capability to execute faulting instructions in software. The
14 * handler does not try to handle the case when the program counter points
15 * to an address not aligned to a word boundary.
16 *
17 * Putting data to unaligned addresses is a bad practice even on Intel where
18 * only the performance is affected. Much worse is that such code is non-
19 * portable. Due to several programs that die on MIPS due to alignment
20 * problems I decided to implement this handler anyway though I originally
21 * didn't intend to do this at all for user code.
22 *
23 * For now I enable fixing of address errors by default to make life easier.
24 * I however intend to disable this somewhen in the future when the alignment
25 * problems with user programs have been fixed. For programmers this is the
26 * right way to go.
27 *
28 * Fixing address errors is a per process option. The option is inherited
29 * across fork(2) and execve(2) calls. If you really want to use the
30 * option in your user programs - I discourage the use of the software
31 * emulation strongly - use the following code in your userland stuff:
32 *
33 * #include <sys/sysmips.h>
34 *
35 * ...
36 * sysmips(MIPS_FIXADE, x);
37 * ...
38 *
39 * The argument x is 0 for disabling software emulation, enabled otherwise.
40 *
41 * Below a little program to play around with this feature.
42 *
43 * #include <stdio.h>
44 * #include <sys/sysmips.h>
45 *
46 * struct foo {
47 * unsigned char bar[8];
48 * };
49 *
50 * main(int argc, char *argv[])
51 * {
52 * struct foo x = {0, 1, 2, 3, 4, 5, 6, 7};
53 * unsigned int *p = (unsigned int *) (x.bar + 3);
54 * int i;
55 *
56 * if (argc > 1)
57 * sysmips(MIPS_FIXADE, atoi(argv[1]));
58 *
59 * printf("*p = %08lx\n", *p);
60 *
61 * *p = 0xdeadface;
62 *
63 * for(i = 0; i <= 7; i++)
64 * printf("%02x ", x.bar[i]);
65 * printf("\n");
66 * }
67 *
68 * Coprocessor loads are not supported; I think this case is unimportant
69 * in the practice.
70 *
71 * TODO: Handle ndc (attempted store to doubleword in uncached memory)
72 * exception for the R6000.
73 * A store crossing a page boundary might be executed only partially.
74 * Undo the partial store in this case.
75 */
76#include <linux/context_tracking.h>
77#include <linux/mm.h>
78#include <linux/signal.h>
79#include <linux/smp.h>
80#include <linux/sched.h>
81#include <linux/debugfs.h>
82#include <linux/perf_event.h>
83
84#include <asm/asm.h>
85#include <asm/branch.h>
86#include <asm/byteorder.h>
87#include <asm/cop2.h>
88#include <asm/debug.h>
89#include <asm/fpu.h>
90#include <asm/fpu_emulator.h>
91#include <asm/inst.h>
92#include <asm/unaligned-emul.h>
93#include <asm/mmu_context.h>
94#include <linux/uaccess.h>
95
96#include "access-helper.h"
97
98enum {
99 UNALIGNED_ACTION_QUIET,
100 UNALIGNED_ACTION_SIGNAL,
101 UNALIGNED_ACTION_SHOW,
102};
103#ifdef CONFIG_DEBUG_FS
104static u32 unaligned_instructions;
105static u32 unaligned_action;
106#else
107#define unaligned_action UNALIGNED_ACTION_QUIET
108#endif
109extern void show_registers(struct pt_regs *regs);
110
111static void emulate_load_store_insn(struct pt_regs *regs,
112 void __user *addr, unsigned int *pc)
113{
114 unsigned long origpc, orig31, value;
115 union mips_instruction insn;
116 unsigned int res;
117 bool user = user_mode(regs);
118
119 origpc = (unsigned long)pc;
120 orig31 = regs->regs[31];
121
122 perf_sw_event(event_id: PERF_COUNT_SW_EMULATION_FAULTS, nr: 1, regs, addr: 0);
123
124 /*
125 * This load never faults.
126 */
127 __get_inst32(i: &insn.word, p: pc, user);
128
129 switch (insn.i_format.opcode) {
130 /*
131 * These are instructions that a compiler doesn't generate. We
132 * can assume therefore that the code is MIPS-aware and
133 * really buggy. Emulating these instructions would break the
134 * semantics anyway.
135 */
136 case ll_op:
137 case lld_op:
138 case sc_op:
139 case scd_op:
140
141 /*
142 * For these instructions the only way to create an address
143 * error is an attempted access to kernel/supervisor address
144 * space.
145 */
146 case ldl_op:
147 case ldr_op:
148 case lwl_op:
149 case lwr_op:
150 case sdl_op:
151 case sdr_op:
152 case swl_op:
153 case swr_op:
154 case lb_op:
155 case lbu_op:
156 case sb_op:
157 goto sigbus;
158
159 /*
160 * The remaining opcodes are the ones that are really of
161 * interest.
162 */
163#ifdef CONFIG_MACH_INGENIC
164 case spec2_op:
165 if (insn.mxu_lx_format.func != mxu_lx_op)
166 goto sigbus; /* other MXU instructions we don't care */
167
168 switch (insn.mxu_lx_format.op) {
169 case mxu_lxw_op:
170 if (user && !access_ok(addr, 4))
171 goto sigbus;
172 LoadW(addr, value, res);
173 if (res)
174 goto fault;
175 compute_return_epc(regs);
176 regs->regs[insn.mxu_lx_format.rd] = value;
177 break;
178 case mxu_lxh_op:
179 if (user && !access_ok(addr, 2))
180 goto sigbus;
181 LoadHW(addr, value, res);
182 if (res)
183 goto fault;
184 compute_return_epc(regs);
185 regs->regs[insn.dsp_format.rd] = value;
186 break;
187 case mxu_lxhu_op:
188 if (user && !access_ok(addr, 2))
189 goto sigbus;
190 LoadHWU(addr, value, res);
191 if (res)
192 goto fault;
193 compute_return_epc(regs);
194 regs->regs[insn.dsp_format.rd] = value;
195 break;
196 case mxu_lxb_op:
197 case mxu_lxbu_op:
198 goto sigbus;
199 default:
200 goto sigill;
201 }
202 break;
203#endif
204 case spec3_op:
205 if (insn.dsp_format.func == lx_op) {
206 switch (insn.dsp_format.op) {
207 case lwx_op:
208 if (user && !access_ok(addr, 4))
209 goto sigbus;
210 LoadW(addr, value, res);
211 if (res)
212 goto fault;
213 compute_return_epc(regs);
214 regs->regs[insn.dsp_format.rd] = value;
215 break;
216 case lhx_op:
217 if (user && !access_ok(addr, 2))
218 goto sigbus;
219 LoadHW(addr, value, res);
220 if (res)
221 goto fault;
222 compute_return_epc(regs);
223 regs->regs[insn.dsp_format.rd] = value;
224 break;
225 default:
226 goto sigill;
227 }
228 }
229#ifdef CONFIG_EVA
230 else {
231 /*
232 * we can land here only from kernel accessing user
233 * memory, so we need to "switch" the address limit to
234 * user space, so that address check can work properly.
235 */
236 switch (insn.spec3_format.func) {
237 case lhe_op:
238 if (!access_ok(addr, 2))
239 goto sigbus;
240 LoadHWE(addr, value, res);
241 if (res)
242 goto fault;
243 compute_return_epc(regs);
244 regs->regs[insn.spec3_format.rt] = value;
245 break;
246 case lwe_op:
247 if (!access_ok(addr, 4))
248 goto sigbus;
249 LoadWE(addr, value, res);
250 if (res)
251 goto fault;
252 compute_return_epc(regs);
253 regs->regs[insn.spec3_format.rt] = value;
254 break;
255 case lhue_op:
256 if (!access_ok(addr, 2))
257 goto sigbus;
258 LoadHWUE(addr, value, res);
259 if (res)
260 goto fault;
261 compute_return_epc(regs);
262 regs->regs[insn.spec3_format.rt] = value;
263 break;
264 case she_op:
265 if (!access_ok(addr, 2))
266 goto sigbus;
267 compute_return_epc(regs);
268 value = regs->regs[insn.spec3_format.rt];
269 StoreHWE(addr, value, res);
270 if (res)
271 goto fault;
272 break;
273 case swe_op:
274 if (!access_ok(addr, 4))
275 goto sigbus;
276 compute_return_epc(regs);
277 value = regs->regs[insn.spec3_format.rt];
278 StoreWE(addr, value, res);
279 if (res)
280 goto fault;
281 break;
282 default:
283 goto sigill;
284 }
285 }
286#endif
287 break;
288 case lh_op:
289 if (user && !access_ok(addr, 2))
290 goto sigbus;
291
292 if (IS_ENABLED(CONFIG_EVA) && user)
293 LoadHWE(addr, value, res);
294 else
295 LoadHW(addr, value, res);
296
297 if (res)
298 goto fault;
299 compute_return_epc(regs);
300 regs->regs[insn.i_format.rt] = value;
301 break;
302
303 case lw_op:
304 if (user && !access_ok(addr, 4))
305 goto sigbus;
306
307 if (IS_ENABLED(CONFIG_EVA) && user)
308 LoadWE(addr, value, res);
309 else
310 LoadW(addr, value, res);
311
312 if (res)
313 goto fault;
314 compute_return_epc(regs);
315 regs->regs[insn.i_format.rt] = value;
316 break;
317
318 case lhu_op:
319 if (user && !access_ok(addr, 2))
320 goto sigbus;
321
322 if (IS_ENABLED(CONFIG_EVA) && user)
323 LoadHWUE(addr, value, res);
324 else
325 LoadHWU(addr, value, res);
326
327 if (res)
328 goto fault;
329 compute_return_epc(regs);
330 regs->regs[insn.i_format.rt] = value;
331 break;
332
333 case lwu_op:
334#ifdef CONFIG_64BIT
335 /*
336 * A 32-bit kernel might be running on a 64-bit processor. But
337 * if we're on a 32-bit processor and an i-cache incoherency
338 * or race makes us see a 64-bit instruction here the sdl/sdr
339 * would blow up, so for now we don't handle unaligned 64-bit
340 * instructions on 32-bit kernels.
341 */
342 if (user && !access_ok(addr, 4))
343 goto sigbus;
344
345 LoadWU(addr, value, res);
346 if (res)
347 goto fault;
348 compute_return_epc(regs);
349 regs->regs[insn.i_format.rt] = value;
350 break;
351#endif /* CONFIG_64BIT */
352
353 /* Cannot handle 64-bit instructions in 32-bit kernel */
354 goto sigill;
355
356 case ld_op:
357#ifdef CONFIG_64BIT
358 /*
359 * A 32-bit kernel might be running on a 64-bit processor. But
360 * if we're on a 32-bit processor and an i-cache incoherency
361 * or race makes us see a 64-bit instruction here the sdl/sdr
362 * would blow up, so for now we don't handle unaligned 64-bit
363 * instructions on 32-bit kernels.
364 */
365 if (user && !access_ok(addr, 8))
366 goto sigbus;
367
368 LoadDW(addr, value, res);
369 if (res)
370 goto fault;
371 compute_return_epc(regs);
372 regs->regs[insn.i_format.rt] = value;
373 break;
374#endif /* CONFIG_64BIT */
375
376 /* Cannot handle 64-bit instructions in 32-bit kernel */
377 goto sigill;
378
379 case sh_op:
380 if (user && !access_ok(addr, 2))
381 goto sigbus;
382
383 compute_return_epc(regs);
384 value = regs->regs[insn.i_format.rt];
385
386 if (IS_ENABLED(CONFIG_EVA) && user)
387 StoreHWE(addr, value, res);
388 else
389 StoreHW(addr, value, res);
390
391 if (res)
392 goto fault;
393 break;
394
395 case sw_op:
396 if (user && !access_ok(addr, 4))
397 goto sigbus;
398
399 compute_return_epc(regs);
400 value = regs->regs[insn.i_format.rt];
401
402 if (IS_ENABLED(CONFIG_EVA) && user)
403 StoreWE(addr, value, res);
404 else
405 StoreW(addr, value, res);
406
407 if (res)
408 goto fault;
409 break;
410
411 case sd_op:
412#ifdef CONFIG_64BIT
413 /*
414 * A 32-bit kernel might be running on a 64-bit processor. But
415 * if we're on a 32-bit processor and an i-cache incoherency
416 * or race makes us see a 64-bit instruction here the sdl/sdr
417 * would blow up, so for now we don't handle unaligned 64-bit
418 * instructions on 32-bit kernels.
419 */
420 if (user && !access_ok(addr, 8))
421 goto sigbus;
422
423 compute_return_epc(regs);
424 value = regs->regs[insn.i_format.rt];
425 StoreDW(addr, value, res);
426 if (res)
427 goto fault;
428 break;
429#endif /* CONFIG_64BIT */
430
431 /* Cannot handle 64-bit instructions in 32-bit kernel */
432 goto sigill;
433
434#ifdef CONFIG_MIPS_FP_SUPPORT
435
436 case lwc1_op:
437 case ldc1_op:
438 case swc1_op:
439 case sdc1_op:
440 case cop1x_op: {
441 void __user *fault_addr = NULL;
442
443 die_if_kernel("Unaligned FP access in kernel code", regs);
444 BUG_ON(!used_math());
445
446 res = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
447 &fault_addr);
448 own_fpu(1); /* Restore FPU state. */
449
450 /* Signal if something went wrong. */
451 process_fpemu_return(res, fault_addr, 0);
452
453 if (res == 0)
454 break;
455 return;
456 }
457#endif /* CONFIG_MIPS_FP_SUPPORT */
458
459#ifdef CONFIG_CPU_HAS_MSA
460
461 case msa_op: {
462 unsigned int wd, preempted;
463 enum msa_2b_fmt df;
464 union fpureg *fpr;
465
466 if (!cpu_has_msa)
467 goto sigill;
468
469 /*
470 * If we've reached this point then userland should have taken
471 * the MSA disabled exception & initialised vector context at
472 * some point in the past.
473 */
474 BUG_ON(!thread_msa_context_live());
475
476 df = insn.msa_mi10_format.df;
477 wd = insn.msa_mi10_format.wd;
478 fpr = &current->thread.fpu.fpr[wd];
479
480 switch (insn.msa_mi10_format.func) {
481 case msa_ld_op:
482 if (!access_ok(addr, sizeof(*fpr)))
483 goto sigbus;
484
485 do {
486 /*
487 * If we have live MSA context keep track of
488 * whether we get preempted in order to avoid
489 * the register context we load being clobbered
490 * by the live context as it's saved during
491 * preemption. If we don't have live context
492 * then it can't be saved to clobber the value
493 * we load.
494 */
495 preempted = test_thread_flag(TIF_USEDMSA);
496
497 res = __copy_from_user_inatomic(fpr, addr,
498 sizeof(*fpr));
499 if (res)
500 goto fault;
501
502 /*
503 * Update the hardware register if it is in use
504 * by the task in this quantum, in order to
505 * avoid having to save & restore the whole
506 * vector context.
507 */
508 preempt_disable();
509 if (test_thread_flag(TIF_USEDMSA)) {
510 write_msa_wr(wd, fpr, df);
511 preempted = 0;
512 }
513 preempt_enable();
514 } while (preempted);
515 break;
516
517 case msa_st_op:
518 if (!access_ok(addr, sizeof(*fpr)))
519 goto sigbus;
520
521 /*
522 * Update from the hardware register if it is in use by
523 * the task in this quantum, in order to avoid having to
524 * save & restore the whole vector context.
525 */
526 preempt_disable();
527 if (test_thread_flag(TIF_USEDMSA))
528 read_msa_wr(wd, fpr, df);
529 preempt_enable();
530
531 res = __copy_to_user_inatomic(addr, fpr, sizeof(*fpr));
532 if (res)
533 goto fault;
534 break;
535
536 default:
537 goto sigbus;
538 }
539
540 compute_return_epc(regs);
541 break;
542 }
543#endif /* CONFIG_CPU_HAS_MSA */
544
545#ifndef CONFIG_CPU_MIPSR6
546 /*
547 * COP2 is available to implementor for application specific use.
548 * It's up to applications to register a notifier chain and do
549 * whatever they have to do, including possible sending of signals.
550 *
551 * This instruction has been reallocated in Release 6
552 */
553 case lwc2_op:
554 cu2_notifier_call_chain(CU2_LWC2_OP, regs);
555 break;
556
557 case ldc2_op:
558 cu2_notifier_call_chain(CU2_LDC2_OP, regs);
559 break;
560
561 case swc2_op:
562 cu2_notifier_call_chain(CU2_SWC2_OP, regs);
563 break;
564
565 case sdc2_op:
566 cu2_notifier_call_chain(CU2_SDC2_OP, regs);
567 break;
568#endif
569 default:
570 /*
571 * Pheeee... We encountered an yet unknown instruction or
572 * cache coherence problem. Die sucker, die ...
573 */
574 goto sigill;
575 }
576
577#ifdef CONFIG_DEBUG_FS
578 unaligned_instructions++;
579#endif
580
581 return;
582
583fault:
584 /* roll back jump/branch */
585 regs->cp0_epc = origpc;
586 regs->regs[31] = orig31;
587 /* Did we have an exception handler installed? */
588 if (fixup_exception(regs))
589 return;
590
591 die_if_kernel("Unhandled kernel unaligned access", regs);
592 force_sig(SIGSEGV);
593
594 return;
595
596sigbus:
597 die_if_kernel("Unhandled kernel unaligned access", regs);
598 force_sig(SIGBUS);
599
600 return;
601
602sigill:
603 die_if_kernel
604 ("Unhandled kernel unaligned access or invalid instruction", regs);
605 force_sig(SIGILL);
606}
607
608/* Recode table from 16-bit register notation to 32-bit GPR. */
609const int reg16to32[] = { 16, 17, 2, 3, 4, 5, 6, 7 };
610
611/* Recode table from 16-bit STORE register notation to 32-bit GPR. */
612static const int reg16to32st[] = { 0, 17, 2, 3, 4, 5, 6, 7 };
613
614static void emulate_load_store_microMIPS(struct pt_regs *regs,
615 void __user *addr)
616{
617 unsigned long value;
618 unsigned int res;
619 int i;
620 unsigned int reg = 0, rvar;
621 unsigned long orig31;
622 u16 __user *pc16;
623 u16 halfword;
624 unsigned int word;
625 unsigned long origpc, contpc;
626 union mips_instruction insn;
627 struct mm_decoded_insn mminsn;
628 bool user = user_mode(regs);
629
630 origpc = regs->cp0_epc;
631 orig31 = regs->regs[31];
632
633 mminsn.micro_mips_mode = 1;
634
635 /*
636 * This load never faults.
637 */
638 pc16 = (unsigned short __user *)msk_isa16_mode(regs->cp0_epc);
639 __get_user(halfword, pc16);
640 pc16++;
641 contpc = regs->cp0_epc + 2;
642 word = ((unsigned int)halfword << 16);
643 mminsn.pc_inc = 2;
644
645 if (!mm_insn_16bit(halfword)) {
646 __get_user(halfword, pc16);
647 pc16++;
648 contpc = regs->cp0_epc + 4;
649 mminsn.pc_inc = 4;
650 word |= halfword;
651 }
652 mminsn.insn = word;
653
654 if (get_user(halfword, pc16))
655 goto fault;
656 mminsn.next_pc_inc = 2;
657 word = ((unsigned int)halfword << 16);
658
659 if (!mm_insn_16bit(halfword)) {
660 pc16++;
661 if (get_user(halfword, pc16))
662 goto fault;
663 mminsn.next_pc_inc = 4;
664 word |= halfword;
665 }
666 mminsn.next_insn = word;
667
668 insn = (union mips_instruction)(mminsn.insn);
669 if (mm_isBranchInstr(regs, mminsn, &contpc))
670 insn = (union mips_instruction)(mminsn.next_insn);
671
672 /* Parse instruction to find what to do */
673
674 switch (insn.mm_i_format.opcode) {
675
676 case mm_pool32a_op:
677 switch (insn.mm_x_format.func) {
678 case mm_lwxs_op:
679 reg = insn.mm_x_format.rd;
680 goto loadW;
681 }
682
683 goto sigbus;
684
685 case mm_pool32b_op:
686 switch (insn.mm_m_format.func) {
687 case mm_lwp_func:
688 reg = insn.mm_m_format.rd;
689 if (reg == 31)
690 goto sigbus;
691
692 if (user && !access_ok(addr, 8))
693 goto sigbus;
694
695 LoadW(addr, value, res);
696 if (res)
697 goto fault;
698 regs->regs[reg] = value;
699 addr += 4;
700 LoadW(addr, value, res);
701 if (res)
702 goto fault;
703 regs->regs[reg + 1] = value;
704 goto success;
705
706 case mm_swp_func:
707 reg = insn.mm_m_format.rd;
708 if (reg == 31)
709 goto sigbus;
710
711 if (user && !access_ok(addr, 8))
712 goto sigbus;
713
714 value = regs->regs[reg];
715 StoreW(addr, value, res);
716 if (res)
717 goto fault;
718 addr += 4;
719 value = regs->regs[reg + 1];
720 StoreW(addr, value, res);
721 if (res)
722 goto fault;
723 goto success;
724
725 case mm_ldp_func:
726#ifdef CONFIG_64BIT
727 reg = insn.mm_m_format.rd;
728 if (reg == 31)
729 goto sigbus;
730
731 if (user && !access_ok(addr, 16))
732 goto sigbus;
733
734 LoadDW(addr, value, res);
735 if (res)
736 goto fault;
737 regs->regs[reg] = value;
738 addr += 8;
739 LoadDW(addr, value, res);
740 if (res)
741 goto fault;
742 regs->regs[reg + 1] = value;
743 goto success;
744#endif /* CONFIG_64BIT */
745
746 goto sigill;
747
748 case mm_sdp_func:
749#ifdef CONFIG_64BIT
750 reg = insn.mm_m_format.rd;
751 if (reg == 31)
752 goto sigbus;
753
754 if (user && !access_ok(addr, 16))
755 goto sigbus;
756
757 value = regs->regs[reg];
758 StoreDW(addr, value, res);
759 if (res)
760 goto fault;
761 addr += 8;
762 value = regs->regs[reg + 1];
763 StoreDW(addr, value, res);
764 if (res)
765 goto fault;
766 goto success;
767#endif /* CONFIG_64BIT */
768
769 goto sigill;
770
771 case mm_lwm32_func:
772 reg = insn.mm_m_format.rd;
773 rvar = reg & 0xf;
774 if ((rvar > 9) || !reg)
775 goto sigill;
776 if (reg & 0x10) {
777 if (user && !access_ok(addr, 4 * (rvar + 1)))
778 goto sigbus;
779 } else {
780 if (user && !access_ok(addr, 4 * rvar))
781 goto sigbus;
782 }
783 if (rvar == 9)
784 rvar = 8;
785 for (i = 16; rvar; rvar--, i++) {
786 LoadW(addr, value, res);
787 if (res)
788 goto fault;
789 addr += 4;
790 regs->regs[i] = value;
791 }
792 if ((reg & 0xf) == 9) {
793 LoadW(addr, value, res);
794 if (res)
795 goto fault;
796 addr += 4;
797 regs->regs[30] = value;
798 }
799 if (reg & 0x10) {
800 LoadW(addr, value, res);
801 if (res)
802 goto fault;
803 regs->regs[31] = value;
804 }
805 goto success;
806
807 case mm_swm32_func:
808 reg = insn.mm_m_format.rd;
809 rvar = reg & 0xf;
810 if ((rvar > 9) || !reg)
811 goto sigill;
812 if (reg & 0x10) {
813 if (user && !access_ok(addr, 4 * (rvar + 1)))
814 goto sigbus;
815 } else {
816 if (user && !access_ok(addr, 4 * rvar))
817 goto sigbus;
818 }
819 if (rvar == 9)
820 rvar = 8;
821 for (i = 16; rvar; rvar--, i++) {
822 value = regs->regs[i];
823 StoreW(addr, value, res);
824 if (res)
825 goto fault;
826 addr += 4;
827 }
828 if ((reg & 0xf) == 9) {
829 value = regs->regs[30];
830 StoreW(addr, value, res);
831 if (res)
832 goto fault;
833 addr += 4;
834 }
835 if (reg & 0x10) {
836 value = regs->regs[31];
837 StoreW(addr, value, res);
838 if (res)
839 goto fault;
840 }
841 goto success;
842
843 case mm_ldm_func:
844#ifdef CONFIG_64BIT
845 reg = insn.mm_m_format.rd;
846 rvar = reg & 0xf;
847 if ((rvar > 9) || !reg)
848 goto sigill;
849 if (reg & 0x10) {
850 if (user && !access_ok(addr, 8 * (rvar + 1)))
851 goto sigbus;
852 } else {
853 if (user && !access_ok(addr, 8 * rvar))
854 goto sigbus;
855 }
856 if (rvar == 9)
857 rvar = 8;
858
859 for (i = 16; rvar; rvar--, i++) {
860 LoadDW(addr, value, res);
861 if (res)
862 goto fault;
863 addr += 4;
864 regs->regs[i] = value;
865 }
866 if ((reg & 0xf) == 9) {
867 LoadDW(addr, value, res);
868 if (res)
869 goto fault;
870 addr += 8;
871 regs->regs[30] = value;
872 }
873 if (reg & 0x10) {
874 LoadDW(addr, value, res);
875 if (res)
876 goto fault;
877 regs->regs[31] = value;
878 }
879 goto success;
880#endif /* CONFIG_64BIT */
881
882 goto sigill;
883
884 case mm_sdm_func:
885#ifdef CONFIG_64BIT
886 reg = insn.mm_m_format.rd;
887 rvar = reg & 0xf;
888 if ((rvar > 9) || !reg)
889 goto sigill;
890 if (reg & 0x10) {
891 if (user && !access_ok(addr, 8 * (rvar + 1)))
892 goto sigbus;
893 } else {
894 if (user && !access_ok(addr, 8 * rvar))
895 goto sigbus;
896 }
897 if (rvar == 9)
898 rvar = 8;
899
900 for (i = 16; rvar; rvar--, i++) {
901 value = regs->regs[i];
902 StoreDW(addr, value, res);
903 if (res)
904 goto fault;
905 addr += 8;
906 }
907 if ((reg & 0xf) == 9) {
908 value = regs->regs[30];
909 StoreDW(addr, value, res);
910 if (res)
911 goto fault;
912 addr += 8;
913 }
914 if (reg & 0x10) {
915 value = regs->regs[31];
916 StoreDW(addr, value, res);
917 if (res)
918 goto fault;
919 }
920 goto success;
921#endif /* CONFIG_64BIT */
922
923 goto sigill;
924
925 /* LWC2, SWC2, LDC2, SDC2 are not serviced */
926 }
927
928 goto sigbus;
929
930 case mm_pool32c_op:
931 switch (insn.mm_m_format.func) {
932 case mm_lwu_func:
933 reg = insn.mm_m_format.rd;
934 goto loadWU;
935 }
936
937 /* LL,SC,LLD,SCD are not serviced */
938 goto sigbus;
939
940#ifdef CONFIG_MIPS_FP_SUPPORT
941 case mm_pool32f_op:
942 switch (insn.mm_x_format.func) {
943 case mm_lwxc1_func:
944 case mm_swxc1_func:
945 case mm_ldxc1_func:
946 case mm_sdxc1_func:
947 goto fpu_emul;
948 }
949
950 goto sigbus;
951
952 case mm_ldc132_op:
953 case mm_sdc132_op:
954 case mm_lwc132_op:
955 case mm_swc132_op: {
956 void __user *fault_addr = NULL;
957
958fpu_emul:
959 /* roll back jump/branch */
960 regs->cp0_epc = origpc;
961 regs->regs[31] = orig31;
962
963 die_if_kernel("Unaligned FP access in kernel code", regs);
964 BUG_ON(!used_math());
965 BUG_ON(!is_fpu_owner());
966
967 res = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
968 &fault_addr);
969 own_fpu(1); /* restore FPU state */
970
971 /* If something went wrong, signal */
972 process_fpemu_return(res, fault_addr, 0);
973
974 if (res == 0)
975 goto success;
976 return;
977 }
978#endif /* CONFIG_MIPS_FP_SUPPORT */
979
980 case mm_lh32_op:
981 reg = insn.mm_i_format.rt;
982 goto loadHW;
983
984 case mm_lhu32_op:
985 reg = insn.mm_i_format.rt;
986 goto loadHWU;
987
988 case mm_lw32_op:
989 reg = insn.mm_i_format.rt;
990 goto loadW;
991
992 case mm_sh32_op:
993 reg = insn.mm_i_format.rt;
994 goto storeHW;
995
996 case mm_sw32_op:
997 reg = insn.mm_i_format.rt;
998 goto storeW;
999
1000 case mm_ld32_op:
1001 reg = insn.mm_i_format.rt;
1002 goto loadDW;
1003
1004 case mm_sd32_op:
1005 reg = insn.mm_i_format.rt;
1006 goto storeDW;
1007
1008 case mm_pool16c_op:
1009 switch (insn.mm16_m_format.func) {
1010 case mm_lwm16_op:
1011 reg = insn.mm16_m_format.rlist;
1012 rvar = reg + 1;
1013 if (user && !access_ok(addr, 4 * rvar))
1014 goto sigbus;
1015
1016 for (i = 16; rvar; rvar--, i++) {
1017 LoadW(addr, value, res);
1018 if (res)
1019 goto fault;
1020 addr += 4;
1021 regs->regs[i] = value;
1022 }
1023 LoadW(addr, value, res);
1024 if (res)
1025 goto fault;
1026 regs->regs[31] = value;
1027
1028 goto success;
1029
1030 case mm_swm16_op:
1031 reg = insn.mm16_m_format.rlist;
1032 rvar = reg + 1;
1033 if (user && !access_ok(addr, 4 * rvar))
1034 goto sigbus;
1035
1036 for (i = 16; rvar; rvar--, i++) {
1037 value = regs->regs[i];
1038 StoreW(addr, value, res);
1039 if (res)
1040 goto fault;
1041 addr += 4;
1042 }
1043 value = regs->regs[31];
1044 StoreW(addr, value, res);
1045 if (res)
1046 goto fault;
1047
1048 goto success;
1049
1050 }
1051
1052 goto sigbus;
1053
1054 case mm_lhu16_op:
1055 reg = reg16to32[insn.mm16_rb_format.rt];
1056 goto loadHWU;
1057
1058 case mm_lw16_op:
1059 reg = reg16to32[insn.mm16_rb_format.rt];
1060 goto loadW;
1061
1062 case mm_sh16_op:
1063 reg = reg16to32st[insn.mm16_rb_format.rt];
1064 goto storeHW;
1065
1066 case mm_sw16_op:
1067 reg = reg16to32st[insn.mm16_rb_format.rt];
1068 goto storeW;
1069
1070 case mm_lwsp16_op:
1071 reg = insn.mm16_r5_format.rt;
1072 goto loadW;
1073
1074 case mm_swsp16_op:
1075 reg = insn.mm16_r5_format.rt;
1076 goto storeW;
1077
1078 case mm_lwgp16_op:
1079 reg = reg16to32[insn.mm16_r3_format.rt];
1080 goto loadW;
1081
1082 default:
1083 goto sigill;
1084 }
1085
1086loadHW:
1087 if (user && !access_ok(addr, 2))
1088 goto sigbus;
1089
1090 LoadHW(addr, value, res);
1091 if (res)
1092 goto fault;
1093 regs->regs[reg] = value;
1094 goto success;
1095
1096loadHWU:
1097 if (user && !access_ok(addr, 2))
1098 goto sigbus;
1099
1100 LoadHWU(addr, value, res);
1101 if (res)
1102 goto fault;
1103 regs->regs[reg] = value;
1104 goto success;
1105
1106loadW:
1107 if (user && !access_ok(addr, 4))
1108 goto sigbus;
1109
1110 LoadW(addr, value, res);
1111 if (res)
1112 goto fault;
1113 regs->regs[reg] = value;
1114 goto success;
1115
1116loadWU:
1117#ifdef CONFIG_64BIT
1118 /*
1119 * A 32-bit kernel might be running on a 64-bit processor. But
1120 * if we're on a 32-bit processor and an i-cache incoherency
1121 * or race makes us see a 64-bit instruction here the sdl/sdr
1122 * would blow up, so for now we don't handle unaligned 64-bit
1123 * instructions on 32-bit kernels.
1124 */
1125 if (user && !access_ok(addr, 4))
1126 goto sigbus;
1127
1128 LoadWU(addr, value, res);
1129 if (res)
1130 goto fault;
1131 regs->regs[reg] = value;
1132 goto success;
1133#endif /* CONFIG_64BIT */
1134
1135 /* Cannot handle 64-bit instructions in 32-bit kernel */
1136 goto sigill;
1137
1138loadDW:
1139#ifdef CONFIG_64BIT
1140 /*
1141 * A 32-bit kernel might be running on a 64-bit processor. But
1142 * if we're on a 32-bit processor and an i-cache incoherency
1143 * or race makes us see a 64-bit instruction here the sdl/sdr
1144 * would blow up, so for now we don't handle unaligned 64-bit
1145 * instructions on 32-bit kernels.
1146 */
1147 if (user && !access_ok(addr, 8))
1148 goto sigbus;
1149
1150 LoadDW(addr, value, res);
1151 if (res)
1152 goto fault;
1153 regs->regs[reg] = value;
1154 goto success;
1155#endif /* CONFIG_64BIT */
1156
1157 /* Cannot handle 64-bit instructions in 32-bit kernel */
1158 goto sigill;
1159
1160storeHW:
1161 if (user && !access_ok(addr, 2))
1162 goto sigbus;
1163
1164 value = regs->regs[reg];
1165 StoreHW(addr, value, res);
1166 if (res)
1167 goto fault;
1168 goto success;
1169
1170storeW:
1171 if (user && !access_ok(addr, 4))
1172 goto sigbus;
1173
1174 value = regs->regs[reg];
1175 StoreW(addr, value, res);
1176 if (res)
1177 goto fault;
1178 goto success;
1179
1180storeDW:
1181#ifdef CONFIG_64BIT
1182 /*
1183 * A 32-bit kernel might be running on a 64-bit processor. But
1184 * if we're on a 32-bit processor and an i-cache incoherency
1185 * or race makes us see a 64-bit instruction here the sdl/sdr
1186 * would blow up, so for now we don't handle unaligned 64-bit
1187 * instructions on 32-bit kernels.
1188 */
1189 if (user && !access_ok(addr, 8))
1190 goto sigbus;
1191
1192 value = regs->regs[reg];
1193 StoreDW(addr, value, res);
1194 if (res)
1195 goto fault;
1196 goto success;
1197#endif /* CONFIG_64BIT */
1198
1199 /* Cannot handle 64-bit instructions in 32-bit kernel */
1200 goto sigill;
1201
1202success:
1203 regs->cp0_epc = contpc; /* advance or branch */
1204
1205#ifdef CONFIG_DEBUG_FS
1206 unaligned_instructions++;
1207#endif
1208 return;
1209
1210fault:
1211 /* roll back jump/branch */
1212 regs->cp0_epc = origpc;
1213 regs->regs[31] = orig31;
1214 /* Did we have an exception handler installed? */
1215 if (fixup_exception(regs))
1216 return;
1217
1218 die_if_kernel("Unhandled kernel unaligned access", regs);
1219 force_sig(SIGSEGV);
1220
1221 return;
1222
1223sigbus:
1224 die_if_kernel("Unhandled kernel unaligned access", regs);
1225 force_sig(SIGBUS);
1226
1227 return;
1228
1229sigill:
1230 die_if_kernel
1231 ("Unhandled kernel unaligned access or invalid instruction", regs);
1232 force_sig(SIGILL);
1233}
1234
1235static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
1236{
1237 unsigned long value;
1238 unsigned int res;
1239 int reg;
1240 unsigned long orig31;
1241 u16 __user *pc16;
1242 unsigned long origpc;
1243 union mips16e_instruction mips16inst, oldinst;
1244 unsigned int opcode;
1245 int extended = 0;
1246 bool user = user_mode(regs);
1247
1248 origpc = regs->cp0_epc;
1249 orig31 = regs->regs[31];
1250 pc16 = (unsigned short __user *)msk_isa16_mode(origpc);
1251 /*
1252 * This load never faults.
1253 */
1254 __get_user(mips16inst.full, pc16);
1255 oldinst = mips16inst;
1256
1257 /* skip EXTEND instruction */
1258 if (mips16inst.ri.opcode == MIPS16e_extend_op) {
1259 extended = 1;
1260 pc16++;
1261 __get_user(mips16inst.full, pc16);
1262 } else if (delay_slot(regs)) {
1263 /* skip jump instructions */
1264 /* JAL/JALX are 32 bits but have OPCODE in first short int */
1265 if (mips16inst.ri.opcode == MIPS16e_jal_op)
1266 pc16++;
1267 pc16++;
1268 if (get_user(mips16inst.full, pc16))
1269 goto sigbus;
1270 }
1271
1272 opcode = mips16inst.ri.opcode;
1273 switch (opcode) {
1274 case MIPS16e_i64_op: /* I64 or RI64 instruction */
1275 switch (mips16inst.i64.func) { /* I64/RI64 func field check */
1276 case MIPS16e_ldpc_func:
1277 case MIPS16e_ldsp_func:
1278 reg = reg16to32[mips16inst.ri64.ry];
1279 goto loadDW;
1280
1281 case MIPS16e_sdsp_func:
1282 reg = reg16to32[mips16inst.ri64.ry];
1283 goto writeDW;
1284
1285 case MIPS16e_sdrasp_func:
1286 reg = 29; /* GPRSP */
1287 goto writeDW;
1288 }
1289
1290 goto sigbus;
1291
1292 case MIPS16e_swsp_op:
1293 reg = reg16to32[mips16inst.ri.rx];
1294 if (extended && cpu_has_mips16e2)
1295 switch (mips16inst.ri.imm >> 5) {
1296 case 0: /* SWSP */
1297 case 1: /* SWGP */
1298 break;
1299 case 2: /* SHGP */
1300 opcode = MIPS16e_sh_op;
1301 break;
1302 default:
1303 goto sigbus;
1304 }
1305 break;
1306
1307 case MIPS16e_lwpc_op:
1308 reg = reg16to32[mips16inst.ri.rx];
1309 break;
1310
1311 case MIPS16e_lwsp_op:
1312 reg = reg16to32[mips16inst.ri.rx];
1313 if (extended && cpu_has_mips16e2)
1314 switch (mips16inst.ri.imm >> 5) {
1315 case 0: /* LWSP */
1316 case 1: /* LWGP */
1317 break;
1318 case 2: /* LHGP */
1319 opcode = MIPS16e_lh_op;
1320 break;
1321 case 4: /* LHUGP */
1322 opcode = MIPS16e_lhu_op;
1323 break;
1324 default:
1325 goto sigbus;
1326 }
1327 break;
1328
1329 case MIPS16e_i8_op:
1330 if (mips16inst.i8.func != MIPS16e_swrasp_func)
1331 goto sigbus;
1332 reg = 29; /* GPRSP */
1333 break;
1334
1335 default:
1336 reg = reg16to32[mips16inst.rri.ry];
1337 break;
1338 }
1339
1340 switch (opcode) {
1341
1342 case MIPS16e_lb_op:
1343 case MIPS16e_lbu_op:
1344 case MIPS16e_sb_op:
1345 goto sigbus;
1346
1347 case MIPS16e_lh_op:
1348 if (user && !access_ok(addr, 2))
1349 goto sigbus;
1350
1351 LoadHW(addr, value, res);
1352 if (res)
1353 goto fault;
1354 MIPS16e_compute_return_epc(regs, &oldinst);
1355 regs->regs[reg] = value;
1356 break;
1357
1358 case MIPS16e_lhu_op:
1359 if (user && !access_ok(addr, 2))
1360 goto sigbus;
1361
1362 LoadHWU(addr, value, res);
1363 if (res)
1364 goto fault;
1365 MIPS16e_compute_return_epc(regs, &oldinst);
1366 regs->regs[reg] = value;
1367 break;
1368
1369 case MIPS16e_lw_op:
1370 case MIPS16e_lwpc_op:
1371 case MIPS16e_lwsp_op:
1372 if (user && !access_ok(addr, 4))
1373 goto sigbus;
1374
1375 LoadW(addr, value, res);
1376 if (res)
1377 goto fault;
1378 MIPS16e_compute_return_epc(regs, &oldinst);
1379 regs->regs[reg] = value;
1380 break;
1381
1382 case MIPS16e_lwu_op:
1383#ifdef CONFIG_64BIT
1384 /*
1385 * A 32-bit kernel might be running on a 64-bit processor. But
1386 * if we're on a 32-bit processor and an i-cache incoherency
1387 * or race makes us see a 64-bit instruction here the sdl/sdr
1388 * would blow up, so for now we don't handle unaligned 64-bit
1389 * instructions on 32-bit kernels.
1390 */
1391 if (user && !access_ok(addr, 4))
1392 goto sigbus;
1393
1394 LoadWU(addr, value, res);
1395 if (res)
1396 goto fault;
1397 MIPS16e_compute_return_epc(regs, &oldinst);
1398 regs->regs[reg] = value;
1399 break;
1400#endif /* CONFIG_64BIT */
1401
1402 /* Cannot handle 64-bit instructions in 32-bit kernel */
1403 goto sigill;
1404
1405 case MIPS16e_ld_op:
1406loadDW:
1407#ifdef CONFIG_64BIT
1408 /*
1409 * A 32-bit kernel might be running on a 64-bit processor. But
1410 * if we're on a 32-bit processor and an i-cache incoherency
1411 * or race makes us see a 64-bit instruction here the sdl/sdr
1412 * would blow up, so for now we don't handle unaligned 64-bit
1413 * instructions on 32-bit kernels.
1414 */
1415 if (user && !access_ok(addr, 8))
1416 goto sigbus;
1417
1418 LoadDW(addr, value, res);
1419 if (res)
1420 goto fault;
1421 MIPS16e_compute_return_epc(regs, &oldinst);
1422 regs->regs[reg] = value;
1423 break;
1424#endif /* CONFIG_64BIT */
1425
1426 /* Cannot handle 64-bit instructions in 32-bit kernel */
1427 goto sigill;
1428
1429 case MIPS16e_sh_op:
1430 if (user && !access_ok(addr, 2))
1431 goto sigbus;
1432
1433 MIPS16e_compute_return_epc(regs, &oldinst);
1434 value = regs->regs[reg];
1435 StoreHW(addr, value, res);
1436 if (res)
1437 goto fault;
1438 break;
1439
1440 case MIPS16e_sw_op:
1441 case MIPS16e_swsp_op:
1442 case MIPS16e_i8_op: /* actually - MIPS16e_swrasp_func */
1443 if (user && !access_ok(addr, 4))
1444 goto sigbus;
1445
1446 MIPS16e_compute_return_epc(regs, &oldinst);
1447 value = regs->regs[reg];
1448 StoreW(addr, value, res);
1449 if (res)
1450 goto fault;
1451 break;
1452
1453 case MIPS16e_sd_op:
1454writeDW:
1455#ifdef CONFIG_64BIT
1456 /*
1457 * A 32-bit kernel might be running on a 64-bit processor. But
1458 * if we're on a 32-bit processor and an i-cache incoherency
1459 * or race makes us see a 64-bit instruction here the sdl/sdr
1460 * would blow up, so for now we don't handle unaligned 64-bit
1461 * instructions on 32-bit kernels.
1462 */
1463 if (user && !access_ok(addr, 8))
1464 goto sigbus;
1465
1466 MIPS16e_compute_return_epc(regs, &oldinst);
1467 value = regs->regs[reg];
1468 StoreDW(addr, value, res);
1469 if (res)
1470 goto fault;
1471 break;
1472#endif /* CONFIG_64BIT */
1473
1474 /* Cannot handle 64-bit instructions in 32-bit kernel */
1475 goto sigill;
1476
1477 default:
1478 /*
1479 * Pheeee... We encountered an yet unknown instruction or
1480 * cache coherence problem. Die sucker, die ...
1481 */
1482 goto sigill;
1483 }
1484
1485#ifdef CONFIG_DEBUG_FS
1486 unaligned_instructions++;
1487#endif
1488
1489 return;
1490
1491fault:
1492 /* roll back jump/branch */
1493 regs->cp0_epc = origpc;
1494 regs->regs[31] = orig31;
1495 /* Did we have an exception handler installed? */
1496 if (fixup_exception(regs))
1497 return;
1498
1499 die_if_kernel("Unhandled kernel unaligned access", regs);
1500 force_sig(SIGSEGV);
1501
1502 return;
1503
1504sigbus:
1505 die_if_kernel("Unhandled kernel unaligned access", regs);
1506 force_sig(SIGBUS);
1507
1508 return;
1509
1510sigill:
1511 die_if_kernel
1512 ("Unhandled kernel unaligned access or invalid instruction", regs);
1513 force_sig(SIGILL);
1514}
1515
1516asmlinkage void do_ade(struct pt_regs *regs)
1517{
1518 enum ctx_state prev_state;
1519 unsigned int *pc;
1520
1521 prev_state = exception_enter();
1522 perf_sw_event(event_id: PERF_COUNT_SW_ALIGNMENT_FAULTS,
1523 nr: 1, regs, addr: regs->cp0_badvaddr);
1524
1525#ifdef CONFIG_64BIT
1526 /*
1527 * check, if we are hitting space between CPU implemented maximum
1528 * virtual user address and 64bit maximum virtual user address
1529 * and do exception handling to get EFAULTs for get_user/put_user
1530 */
1531 if ((regs->cp0_badvaddr >= (1UL << cpu_vmbits)) &&
1532 (regs->cp0_badvaddr < XKSSEG)) {
1533 if (fixup_exception(regs)) {
1534 current->thread.cp0_baduaddr = regs->cp0_badvaddr;
1535 return;
1536 }
1537 goto sigbus;
1538 }
1539#endif
1540
1541 /*
1542 * Did we catch a fault trying to load an instruction?
1543 */
1544 if (regs->cp0_badvaddr == regs->cp0_epc)
1545 goto sigbus;
1546
1547 if (user_mode(regs) && !test_thread_flag(TIF_FIXADE))
1548 goto sigbus;
1549 if (unaligned_action == UNALIGNED_ACTION_SIGNAL)
1550 goto sigbus;
1551
1552 /*
1553 * Do branch emulation only if we didn't forward the exception.
1554 * This is all so but ugly ...
1555 */
1556
1557 /*
1558 * Are we running in microMIPS mode?
1559 */
1560 if (get_isa16_mode(regs->cp0_epc)) {
1561 /*
1562 * Did we catch a fault trying to load an instruction in
1563 * 16-bit mode?
1564 */
1565 if (regs->cp0_badvaddr == msk_isa16_mode(regs->cp0_epc))
1566 goto sigbus;
1567 if (unaligned_action == UNALIGNED_ACTION_SHOW)
1568 show_registers(regs);
1569
1570 if (cpu_has_mmips) {
1571 emulate_load_store_microMIPS(regs,
1572 addr: (void __user *)regs->cp0_badvaddr);
1573 return;
1574 }
1575
1576 if (cpu_has_mips16) {
1577 emulate_load_store_MIPS16e(regs,
1578 addr: (void __user *)regs->cp0_badvaddr);
1579 return;
1580 }
1581
1582 goto sigbus;
1583 }
1584
1585 if (unaligned_action == UNALIGNED_ACTION_SHOW)
1586 show_registers(regs);
1587 pc = (unsigned int *)exception_epc(regs);
1588
1589 emulate_load_store_insn(regs, addr: (void __user *)regs->cp0_badvaddr, pc);
1590
1591 return;
1592
1593sigbus:
1594 die_if_kernel("Kernel unaligned instruction access", regs);
1595 force_sig(SIGBUS);
1596
1597 /*
1598 * XXX On return from the signal handler we should advance the epc
1599 */
1600 exception_exit(prev_ctx: prev_state);
1601}
1602
1603#ifdef CONFIG_DEBUG_FS
1604static int __init debugfs_unaligned(void)
1605{
1606 debugfs_create_u32("unaligned_instructions", S_IRUGO, mips_debugfs_dir,
1607 &unaligned_instructions);
1608 debugfs_create_u32("unaligned_action", S_IRUGO | S_IWUSR,
1609 mips_debugfs_dir, &unaligned_action);
1610 return 0;
1611}
1612arch_initcall(debugfs_unaligned);
1613#endif
1614

source code of linux/arch/mips/kernel/unaligned.c