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1/*
2 * 'traps.c' handles hardware traps and faults after we have saved some
3 * state in 'entry.S'.
4 *
5 * SuperH version: Copyright (C) 1999 Niibe Yutaka
6 * Copyright (C) 2000 Philipp Rumpf
7 * Copyright (C) 2000 David Howells
8 * Copyright (C) 2002 - 2010 Paul Mundt
9 *
10 * This file is subject to the terms and conditions of the GNU General Public
11 * License. See the file "COPYING" in the main directory of this archive
12 * for more details.
13 */
14#include <linux/kernel.h>
15#include <linux/ptrace.h>
16#include <linux/hardirq.h>
17#include <linux/init.h>
18#include <linux/spinlock.h>
19#include <linux/module.h>
20#include <linux/kallsyms.h>
21#include <linux/io.h>
22#include <linux/bug.h>
23#include <linux/debug_locks.h>
24#include <linux/kdebug.h>
25#include <linux/kexec.h>
26#include <linux/limits.h>
27#include <linux/sysfs.h>
28#include <linux/uaccess.h>
29#include <linux/perf_event.h>
30#include <asm/alignment.h>
31#include <asm/fpu.h>
32#include <asm/kprobes.h>
33#include <asm/traps.h>
34#include <asm/bl_bit.h>
35
36#ifdef CONFIG_CPU_SH2
37# define TRAP_RESERVED_INST 4
38# define TRAP_ILLEGAL_SLOT_INST 6
39# define TRAP_ADDRESS_ERROR 9
40# ifdef CONFIG_CPU_SH2A
41# define TRAP_UBC 12
42# define TRAP_FPU_ERROR 13
43# define TRAP_DIVZERO_ERROR 17
44# define TRAP_DIVOVF_ERROR 18
45# endif
46#else
47#define TRAP_RESERVED_INST 12
48#define TRAP_ILLEGAL_SLOT_INST 13
49#endif
50
51static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
52{
53 unsigned long p;
54 int i;
55
56 printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
57
58 for (p = bottom & ~31; p < top; ) {
59 printk("%04lx: ", p & 0xffff);
60
61 for (i = 0; i < 8; i++, p += 4) {
62 unsigned int val;
63
64 if (p < bottom || p >= top)
65 printk(" ");
66 else {
67 if (__get_user(val, (unsigned int __user *)p)) {
68 printk("\n");
69 return;
70 }
71 printk("%08x ", val);
72 }
73 }
74 printk("\n");
75 }
76}
77
78static DEFINE_SPINLOCK(die_lock);
79
80void die(const char * str, struct pt_regs * regs, long err)
81{
82 static int die_counter;
83
84 oops_enter();
85
86 spin_lock_irq(&die_lock);
87 console_verbose();
88 bust_spinlocks(1);
89
90 printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
91 print_modules();
92 show_regs(regs);
93
94 printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
95 task_pid_nr(current), task_stack_page(current) + 1);
96
97 if (!user_mode(regs) || in_interrupt())
98 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
99 (unsigned long)task_stack_page(current));
100
101 notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
102
103 bust_spinlocks(0);
104 add_taint(TAINT_DIE);
105 spin_unlock_irq(&die_lock);
106 oops_exit();
107
108 if (kexec_should_crash(current))
109 crash_kexec(regs);
110
111 if (in_interrupt())
112 panic("Fatal exception in interrupt");
113
114 if (panic_on_oops)
115 panic("Fatal exception");
116
117 do_exit(SIGSEGV);
118}
119
120static inline void die_if_kernel(const char *str, struct pt_regs *regs,
121 long err)
122{
123 if (!user_mode(regs))
124 die(str, regs, err);
125}
126
127/*
128 * try and fix up kernelspace address errors
129 * - userspace errors just cause EFAULT to be returned, resulting in SEGV
130 * - kernel/userspace interfaces cause a jump to an appropriate handler
131 * - other kernel errors are bad
132 */
133static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
134{
135 if (!user_mode(regs)) {
136 const struct exception_table_entry *fixup;
137 fixup = search_exception_tables(regs->pc);
138 if (fixup) {
139 regs->pc = fixup->fixup;
140 return;
141 }
142
143 die(str, regs, err);
144 }
145}
146
147static inline void sign_extend(unsigned int count, unsigned char *dst)
148{
149#ifdef __LITTLE_ENDIAN__
150 if ((count == 1) && dst[0] & 0x80) {
151 dst[1] = 0xff;
152 dst[2] = 0xff;
153 dst[3] = 0xff;
154 }
155 if ((count == 2) && dst[1] & 0x80) {
156 dst[2] = 0xff;
157 dst[3] = 0xff;
158 }
159#else
160 if ((count == 1) && dst[3] & 0x80) {
161 dst[2] = 0xff;
162 dst[1] = 0xff;
163 dst[0] = 0xff;
164 }
165 if ((count == 2) && dst[2] & 0x80) {
166 dst[1] = 0xff;
167 dst[0] = 0xff;
168 }
169#endif
170}
171
172static struct mem_access user_mem_access = {
173 copy_from_user,
174 copy_to_user,
175};
176
177/*
178 * handle an instruction that does an unaligned memory access by emulating the
179 * desired behaviour
180 * - note that PC _may not_ point to the faulting instruction
181 * (if that instruction is in a branch delay slot)
182 * - return 0 if emulation okay, -EFAULT on existential error
183 */
184static int handle_unaligned_ins(insn_size_t instruction, struct pt_regs *regs,
185 struct mem_access *ma)
186{
187 int ret, index, count;
188 unsigned long *rm, *rn;
189 unsigned char *src, *dst;
190 unsigned char __user *srcu, *dstu;
191
192 index = (instruction>>8)&15; /* 0x0F00 */
193 rn = ®s->regs[index];
194
195 index = (instruction>>4)&15; /* 0x00F0 */
196 rm = ®s->regs[index];
197
198 count = 1<<(instruction&3);
199
200 switch (count) {
201 case 1: inc_unaligned_byte_access(); break;
202 case 2: inc_unaligned_word_access(); break;
203 case 4: inc_unaligned_dword_access(); break;
204 case 8: inc_unaligned_multi_access(); break;
205 }
206
207 ret = -EFAULT;
208 switch (instruction>>12) {
209 case 0: /* mov.[bwl] to/from memory via r0+rn */
210 if (instruction & 8) {
211 /* from memory */
212 srcu = (unsigned char __user *)*rm;
213 srcu += regs->regs[0];
214 dst = (unsigned char *)rn;
215 *(unsigned long *)dst = 0;
216
217#if !defined(__LITTLE_ENDIAN__)
218 dst += 4-count;
219#endif
220 if (ma->from(dst, srcu, count))
221 goto fetch_fault;
222
223 sign_extend(count, dst);
224 } else {
225 /* to memory */
226 src = (unsigned char *)rm;
227#if !defined(__LITTLE_ENDIAN__)
228 src += 4-count;
229#endif
230 dstu = (unsigned char __user *)*rn;
231 dstu += regs->regs[0];
232
233 if (ma->to(dstu, src, count))
234 goto fetch_fault;
235 }
236 ret = 0;
237 break;
238
239 case 1: /* mov.l Rm,@(disp,Rn) */
240 src = (unsigned char*) rm;
241 dstu = (unsigned char __user *)*rn;
242 dstu += (instruction&0x000F)<<2;
243
244 if (ma->to(dstu, src, 4))
245 goto fetch_fault;
246 ret = 0;
247 break;
248
249 case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
250 if (instruction & 4)
251 *rn -= count;
252 src = (unsigned char*) rm;
253 dstu = (unsigned char __user *)*rn;
254#if !defined(__LITTLE_ENDIAN__)
255 src += 4-count;
256#endif
257 if (ma->to(dstu, src, count))
258 goto fetch_fault;
259 ret = 0;
260 break;
261
262 case 5: /* mov.l @(disp,Rm),Rn */
263 srcu = (unsigned char __user *)*rm;
264 srcu += (instruction & 0x000F) << 2;
265 dst = (unsigned char *)rn;
266 *(unsigned long *)dst = 0;
267
268 if (ma->from(dst, srcu, 4))
269 goto fetch_fault;
270 ret = 0;
271 break;
272
273 case 6: /* mov.[bwl] from memory, possibly with post-increment */
274 srcu = (unsigned char __user *)*rm;
275 if (instruction & 4)
276 *rm += count;
277 dst = (unsigned char*) rn;
278 *(unsigned long*)dst = 0;
279
280#if !defined(__LITTLE_ENDIAN__)
281 dst += 4-count;
282#endif
283 if (ma->from(dst, srcu, count))
284 goto fetch_fault;
285 sign_extend(count, dst);
286 ret = 0;
287 break;
288
289 case 8:
290 switch ((instruction&0xFF00)>>8) {
291 case 0x81: /* mov.w R0,@(disp,Rn) */
292 src = (unsigned char *) ®s->regs[0];
293#if !defined(__LITTLE_ENDIAN__)
294 src += 2;
295#endif
296 dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
297 dstu += (instruction & 0x000F) << 1;
298
299 if (ma->to(dstu, src, 2))
300 goto fetch_fault;
301 ret = 0;
302 break;
303
304 case 0x85: /* mov.w @(disp,Rm),R0 */
305 srcu = (unsigned char __user *)*rm;
306 srcu += (instruction & 0x000F) << 1;
307 dst = (unsigned char *) ®s->regs[0];
308 *(unsigned long *)dst = 0;
309
310#if !defined(__LITTLE_ENDIAN__)
311 dst += 2;
312#endif
313 if (ma->from(dst, srcu, 2))
314 goto fetch_fault;
315 sign_extend(2, dst);
316 ret = 0;
317 break;
318 }
319 break;
320
321 case 9: /* mov.w @(disp,PC),Rn */
322 srcu = (unsigned char __user *)regs->pc;
323 srcu += 4;
324 srcu += (instruction & 0x00FF) << 1;
325 dst = (unsigned char *)rn;
326 *(unsigned long *)dst = 0;
327
328#if !defined(__LITTLE_ENDIAN__)
329 dst += 2;
330#endif
331
332 if (ma->from(dst, srcu, 2))
333 goto fetch_fault;
334 sign_extend(2, dst);
335 ret = 0;
336 break;
337
338 case 0xd: /* mov.l @(disp,PC),Rn */
339 srcu = (unsigned char __user *)(regs->pc & ~0x3);
340 srcu += 4;
341 srcu += (instruction & 0x00FF) << 2;
342 dst = (unsigned char *)rn;
343 *(unsigned long *)dst = 0;
344
345 if (ma->from(dst, srcu, 4))
346 goto fetch_fault;
347 ret = 0;
348 break;
349 }
350 return ret;
351
352 fetch_fault:
353 /* Argh. Address not only misaligned but also non-existent.
354 * Raise an EFAULT and see if it's trapped
355 */
356 die_if_no_fixup("Fault in unaligned fixup", regs, 0);
357 return -EFAULT;
358}
359
360/*
361 * emulate the instruction in the delay slot
362 * - fetches the instruction from PC+2
363 */
364static inline int handle_delayslot(struct pt_regs *regs,
365 insn_size_t old_instruction,
366 struct mem_access *ma)
367{
368 insn_size_t instruction;
369 void __user *addr = (void __user *)(regs->pc +
370 instruction_size(old_instruction));
371
372 if (copy_from_user(&instruction, addr, sizeof(instruction))) {
373 /* the instruction-fetch faulted */
374 if (user_mode(regs))
375 return -EFAULT;
376
377 /* kernel */
378 die("delay-slot-insn faulting in handle_unaligned_delayslot",
379 regs, 0);
380 }
381
382 return handle_unaligned_ins(instruction, regs, ma);
383}
384
385/*
386 * handle an instruction that does an unaligned memory access
387 * - have to be careful of branch delay-slot instructions that fault
388 * SH3:
389 * - if the branch would be taken PC points to the branch
390 * - if the branch would not be taken, PC points to delay-slot
391 * SH4:
392 * - PC always points to delayed branch
393 * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
394 */
395
396/* Macros to determine offset from current PC for branch instructions */
397/* Explicit type coercion is used to force sign extension where needed */
398#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
399#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
400
401int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
402 struct mem_access *ma, int expected,
403 unsigned long address)
404{
405 u_int rm;
406 int ret, index;
407
408 /*
409 * XXX: We can't handle mixed 16/32-bit instructions yet
410 */
411 if (instruction_size(instruction) != 2)
412 return -EINVAL;
413
414 index = (instruction>>8)&15; /* 0x0F00 */
415 rm = regs->regs[index];
416
417 /*
418 * Log the unexpected fixups, and then pass them on to perf.
419 *
420 * We intentionally don't report the expected cases to perf as
421 * otherwise the trapped I/O case will skew the results too much
422 * to be useful.
423 */
424 if (!expected) {
425 unaligned_fixups_notify(current, instruction, regs);
426 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1,
427 regs, address);
428 }
429
430 ret = -EFAULT;
431 switch (instruction&0xF000) {
432 case 0x0000:
433 if (instruction==0x000B) {
434 /* rts */
435 ret = handle_delayslot(regs, instruction, ma);
436 if (ret==0)
437 regs->pc = regs->pr;
438 }
439 else if ((instruction&0x00FF)==0x0023) {
440 /* braf @Rm */
441 ret = handle_delayslot(regs, instruction, ma);
442 if (ret==0)
443 regs->pc += rm + 4;
444 }
445 else if ((instruction&0x00FF)==0x0003) {
446 /* bsrf @Rm */
447 ret = handle_delayslot(regs, instruction, ma);
448 if (ret==0) {
449 regs->pr = regs->pc + 4;
450 regs->pc += rm + 4;
451 }
452 }
453 else {
454 /* mov.[bwl] to/from memory via r0+rn */
455 goto simple;
456 }
457 break;
458
459 case 0x1000: /* mov.l Rm,@(disp,Rn) */
460 goto simple;
461
462 case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
463 goto simple;
464
465 case 0x4000:
466 if ((instruction&0x00FF)==0x002B) {
467 /* jmp @Rm */
468 ret = handle_delayslot(regs, instruction, ma);
469 if (ret==0)
470 regs->pc = rm;
471 }
472 else if ((instruction&0x00FF)==0x000B) {
473 /* jsr @Rm */
474 ret = handle_delayslot(regs, instruction, ma);
475 if (ret==0) {
476 regs->pr = regs->pc + 4;
477 regs->pc = rm;
478 }
479 }
480 else {
481 /* mov.[bwl] to/from memory via r0+rn */
482 goto simple;
483 }
484 break;
485
486 case 0x5000: /* mov.l @(disp,Rm),Rn */
487 goto simple;
488
489 case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
490 goto simple;
491
492 case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
493 switch (instruction&0x0F00) {
494 case 0x0100: /* mov.w R0,@(disp,Rm) */
495 goto simple;
496 case 0x0500: /* mov.w @(disp,Rm),R0 */
497 goto simple;
498 case 0x0B00: /* bf lab - no delayslot*/
499 ret = 0;
500 break;
501 case 0x0F00: /* bf/s lab */
502 ret = handle_delayslot(regs, instruction, ma);
503 if (ret==0) {
504#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
505 if ((regs->sr & 0x00000001) != 0)
506 regs->pc += 4; /* next after slot */
507 else
508#endif
509 regs->pc += SH_PC_8BIT_OFFSET(instruction);
510 }
511 break;
512 case 0x0900: /* bt lab - no delayslot */
513 ret = 0;
514 break;
515 case 0x0D00: /* bt/s lab */
516 ret = handle_delayslot(regs, instruction, ma);
517 if (ret==0) {
518#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
519 if ((regs->sr & 0x00000001) == 0)
520 regs->pc += 4; /* next after slot */
521 else
522#endif
523 regs->pc += SH_PC_8BIT_OFFSET(instruction);
524 }
525 break;
526 }
527 break;
528
529 case 0x9000: /* mov.w @(disp,Rm),Rn */
530 goto simple;
531
532 case 0xA000: /* bra label */
533 ret = handle_delayslot(regs, instruction, ma);
534 if (ret==0)
535 regs->pc += SH_PC_12BIT_OFFSET(instruction);
536 break;
537
538 case 0xB000: /* bsr label */
539 ret = handle_delayslot(regs, instruction, ma);
540 if (ret==0) {
541 regs->pr = regs->pc + 4;
542 regs->pc += SH_PC_12BIT_OFFSET(instruction);
543 }
544 break;
545
546 case 0xD000: /* mov.l @(disp,Rm),Rn */
547 goto simple;
548 }
549 return ret;
550
551 /* handle non-delay-slot instruction */
552 simple:
553 ret = handle_unaligned_ins(instruction, regs, ma);
554 if (ret==0)
555 regs->pc += instruction_size(instruction);
556 return ret;
557}
558
559/*
560 * Handle various address error exceptions:
561 * - instruction address error:
562 * misaligned PC
563 * PC >= 0x80000000 in user mode
564 * - data address error (read and write)
565 * misaligned data access
566 * access to >= 0x80000000 is user mode
567 * Unfortuntaly we can't distinguish between instruction address error
568 * and data address errors caused by read accesses.
569 */
570asmlinkage void do_address_error(struct pt_regs *regs,
571 unsigned long writeaccess,
572 unsigned long address)
573{
574 unsigned long error_code = 0;
575 mm_segment_t oldfs;
576 siginfo_t info;
577 insn_size_t instruction;
578 int tmp;
579
580 /* Intentional ifdef */
581#ifdef CONFIG_CPU_HAS_SR_RB
582 error_code = lookup_exception_vector();
583#endif
584
585 oldfs = get_fs();
586
587 if (user_mode(regs)) {
588 int si_code = BUS_ADRERR;
589 unsigned int user_action;
590
591 local_irq_enable();
592 inc_unaligned_user_access();
593
594 set_fs(USER_DS);
595 if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
596 sizeof(instruction))) {
597 set_fs(oldfs);
598 goto uspace_segv;
599 }
600 set_fs(oldfs);
601
602 /* shout about userspace fixups */
603 unaligned_fixups_notify(current, instruction, regs);
604
605 user_action = unaligned_user_action();
606 if (user_action & UM_FIXUP)
607 goto fixup;
608 if (user_action & UM_SIGNAL)
609 goto uspace_segv;
610 else {
611 /* ignore */
612 regs->pc += instruction_size(instruction);
613 return;
614 }
615
616fixup:
617 /* bad PC is not something we can fix */
618 if (regs->pc & 1) {
619 si_code = BUS_ADRALN;
620 goto uspace_segv;
621 }
622
623 set_fs(USER_DS);
624 tmp = handle_unaligned_access(instruction, regs,
625 &user_mem_access, 0,
626 address);
627 set_fs(oldfs);
628
629 if (tmp == 0)
630 return; /* sorted */
631uspace_segv:
632 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
633 "access (PC %lx PR %lx)\n", current->comm, regs->pc,
634 regs->pr);
635
636 info.si_signo = SIGBUS;
637 info.si_errno = 0;
638 info.si_code = si_code;
639 info.si_addr = (void __user *)address;
640 force_sig_info(SIGBUS, &info, current);
641 } else {
642 inc_unaligned_kernel_access();
643
644 if (regs->pc & 1)
645 die("unaligned program counter", regs, error_code);
646
647 set_fs(KERNEL_DS);
648 if (copy_from_user(&instruction, (void __user *)(regs->pc),
649 sizeof(instruction))) {
650 /* Argh. Fault on the instruction itself.
651 This should never happen non-SMP
652 */
653 set_fs(oldfs);
654 die("insn faulting in do_address_error", regs, 0);
655 }
656
657 unaligned_fixups_notify(current, instruction, regs);
658
659 handle_unaligned_access(instruction, regs, &user_mem_access,
660 0, address);
661 set_fs(oldfs);
662 }
663}
664
665#ifdef CONFIG_SH_DSP
666/*
667 * SH-DSP support gerg@snapgear.com.
668 */
669int is_dsp_inst(struct pt_regs *regs)
670{
671 unsigned short inst = 0;
672
673 /*
674 * Safe guard if DSP mode is already enabled or we're lacking
675 * the DSP altogether.
676 */
677 if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
678 return 0;
679
680 get_user(inst, ((unsigned short *) regs->pc));
681
682 inst &= 0xf000;
683
684 /* Check for any type of DSP or support instruction */
685 if ((inst == 0xf000) || (inst == 0x4000))
686 return 1;
687
688 return 0;
689}
690#else
691#define is_dsp_inst(regs) (0)
692#endif /* CONFIG_SH_DSP */
693
694#ifdef CONFIG_CPU_SH2A
695asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
696 unsigned long r6, unsigned long r7,
697 struct pt_regs __regs)
698{
699 siginfo_t info;
700
701 switch (r4) {
702 case TRAP_DIVZERO_ERROR:
703 info.si_code = FPE_INTDIV;
704 break;
705 case TRAP_DIVOVF_ERROR:
706 info.si_code = FPE_INTOVF;
707 break;
708 }
709
710 force_sig_info(SIGFPE, &info, current);
711}
712#endif
713
714asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
715 unsigned long r6, unsigned long r7,
716 struct pt_regs __regs)
717{
718 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
719 unsigned long error_code;
720 struct task_struct *tsk = current;
721
722#ifdef CONFIG_SH_FPU_EMU
723 unsigned short inst = 0;
724 int err;
725
726 get_user(inst, (unsigned short*)regs->pc);
727
728 err = do_fpu_inst(inst, regs);
729 if (!err) {
730 regs->pc += instruction_size(inst);
731 return;
732 }
733 /* not a FPU inst. */
734#endif
735
736#ifdef CONFIG_SH_DSP
737 /* Check if it's a DSP instruction */
738 if (is_dsp_inst(regs)) {
739 /* Enable DSP mode, and restart instruction. */
740 regs->sr |= SR_DSP;
741 /* Save DSP mode */
742 tsk->thread.dsp_status.status |= SR_DSP;
743 return;
744 }
745#endif
746
747 error_code = lookup_exception_vector();
748
749 local_irq_enable();
750 force_sig(SIGILL, tsk);
751 die_if_no_fixup("reserved instruction", regs, error_code);
752}
753
754#ifdef CONFIG_SH_FPU_EMU
755static int emulate_branch(unsigned short inst, struct pt_regs *regs)
756{
757 /*
758 * bfs: 8fxx: PC+=d*2+4;
759 * bts: 8dxx: PC+=d*2+4;
760 * bra: axxx: PC+=D*2+4;
761 * bsr: bxxx: PC+=D*2+4 after PR=PC+4;
762 * braf:0x23: PC+=Rn*2+4;
763 * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
764 * jmp: 4x2b: PC=Rn;
765 * jsr: 4x0b: PC=Rn after PR=PC+4;
766 * rts: 000b: PC=PR;
767 */
768 if (((inst & 0xf000) == 0xb000) || /* bsr */
769 ((inst & 0xf0ff) == 0x0003) || /* bsrf */
770 ((inst & 0xf0ff) == 0x400b)) /* jsr */
771 regs->pr = regs->pc + 4;
772
773 if ((inst & 0xfd00) == 0x8d00) { /* bfs, bts */
774 regs->pc += SH_PC_8BIT_OFFSET(inst);
775 return 0;
776 }
777
778 if ((inst & 0xe000) == 0xa000) { /* bra, bsr */
779 regs->pc += SH_PC_12BIT_OFFSET(inst);
780 return 0;
781 }
782
783 if ((inst & 0xf0df) == 0x0003) { /* braf, bsrf */
784 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
785 return 0;
786 }
787
788 if ((inst & 0xf0df) == 0x400b) { /* jmp, jsr */
789 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
790 return 0;
791 }
792
793 if ((inst & 0xffff) == 0x000b) { /* rts */
794 regs->pc = regs->pr;
795 return 0;
796 }
797
798 return 1;
799}
800#endif
801
802asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
803 unsigned long r6, unsigned long r7,
804 struct pt_regs __regs)
805{
806 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
807 unsigned long inst;
808 struct task_struct *tsk = current;
809
810 if (kprobe_handle_illslot(regs->pc) == 0)
811 return;
812
813#ifdef CONFIG_SH_FPU_EMU
814 get_user(inst, (unsigned short *)regs->pc + 1);
815 if (!do_fpu_inst(inst, regs)) {
816 get_user(inst, (unsigned short *)regs->pc);
817 if (!emulate_branch(inst, regs))
818 return;
819 /* fault in branch.*/
820 }
821 /* not a FPU inst. */
822#endif
823
824 inst = lookup_exception_vector();
825
826 local_irq_enable();
827 force_sig(SIGILL, tsk);
828 die_if_no_fixup("illegal slot instruction", regs, inst);
829}
830
831asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
832 unsigned long r6, unsigned long r7,
833 struct pt_regs __regs)
834{
835 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
836 long ex;
837
838 ex = lookup_exception_vector();
839 die_if_kernel("exception", regs, ex);
840}
841
842void __cpuinit per_cpu_trap_init(void)
843{
844 extern void *vbr_base;
845
846 /* NOTE: The VBR value should be at P1
847 (or P2, virtural "fixed" address space).
848 It's definitely should not in physical address. */
849
850 asm volatile("ldc %0, vbr"
851 : /* no output */
852 : "r" (&vbr_base)
853 : "memory");
854
855 /* disable exception blocking now when the vbr has been setup */
856 clear_bl_bit();
857}
858
859void *set_exception_table_vec(unsigned int vec, void *handler)
860{
861 extern void *exception_handling_table[];
862 void *old_handler;
863
864 old_handler = exception_handling_table[vec];
865 exception_handling_table[vec] = handler;
866 return old_handler;
867}
868
869void __init trap_init(void)
870{
871 set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
872 set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
873
874#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
875 defined(CONFIG_SH_FPU_EMU)
876 /*
877 * For SH-4 lacking an FPU, treat floating point instructions as
878 * reserved. They'll be handled in the math-emu case, or faulted on
879 * otherwise.
880 */
881 set_exception_table_evt(0x800, do_reserved_inst);
882 set_exception_table_evt(0x820, do_illegal_slot_inst);
883#elif defined(CONFIG_SH_FPU)
884 set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
885 set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
886#endif
887
888#ifdef CONFIG_CPU_SH2
889 set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
890#endif
891#ifdef CONFIG_CPU_SH2A
892 set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
893 set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
894#ifdef CONFIG_SH_FPU
895 set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
896#endif
897#endif
898
899#ifdef TRAP_UBC
900 set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler);
901#endif
902}
903
904void show_stack(struct task_struct *tsk, unsigned long *sp)
905{
906 unsigned long stack;
907
908 if (!tsk)
909 tsk = current;
910 if (tsk == current)
911 sp = (unsigned long *)current_stack_pointer;
912 else
913 sp = (unsigned long *)tsk->thread.sp;
914
915 stack = (unsigned long)sp;
916 dump_mem("Stack: ", stack, THREAD_SIZE +
917 (unsigned long)task_stack_page(tsk));
918 show_trace(tsk, sp, NULL);
919}
920
921void dump_stack(void)
922{
923 show_stack(NULL, NULL);
924}
925EXPORT_SYMBOL(dump_stack);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * 'traps.c' handles hardware traps and faults after we have saved some
4 * state in 'entry.S'.
5 *
6 * SuperH version: Copyright (C) 1999 Niibe Yutaka
7 * Copyright (C) 2000 Philipp Rumpf
8 * Copyright (C) 2000 David Howells
9 * Copyright (C) 2002 - 2010 Paul Mundt
10 */
11#include <linux/kernel.h>
12#include <linux/ptrace.h>
13#include <linux/hardirq.h>
14#include <linux/init.h>
15#include <linux/spinlock.h>
16#include <linux/kallsyms.h>
17#include <linux/io.h>
18#include <linux/bug.h>
19#include <linux/debug_locks.h>
20#include <linux/kdebug.h>
21#include <linux/limits.h>
22#include <linux/sysfs.h>
23#include <linux/uaccess.h>
24#include <linux/perf_event.h>
25#include <linux/sched/task_stack.h>
26
27#include <asm/alignment.h>
28#include <asm/fpu.h>
29#include <asm/kprobes.h>
30#include <asm/setup.h>
31#include <asm/traps.h>
32#include <asm/bl_bit.h>
33
34#ifdef CONFIG_CPU_SH2
35# define TRAP_RESERVED_INST 4
36# define TRAP_ILLEGAL_SLOT_INST 6
37# define TRAP_ADDRESS_ERROR 9
38# ifdef CONFIG_CPU_SH2A
39# define TRAP_UBC 12
40# define TRAP_FPU_ERROR 13
41# define TRAP_DIVZERO_ERROR 17
42# define TRAP_DIVOVF_ERROR 18
43# endif
44#else
45#define TRAP_RESERVED_INST 12
46#define TRAP_ILLEGAL_SLOT_INST 13
47#endif
48
49static inline void sign_extend(unsigned int count, unsigned char *dst)
50{
51#ifdef __LITTLE_ENDIAN__
52 if ((count == 1) && dst[0] & 0x80) {
53 dst[1] = 0xff;
54 dst[2] = 0xff;
55 dst[3] = 0xff;
56 }
57 if ((count == 2) && dst[1] & 0x80) {
58 dst[2] = 0xff;
59 dst[3] = 0xff;
60 }
61#else
62 if ((count == 1) && dst[3] & 0x80) {
63 dst[2] = 0xff;
64 dst[1] = 0xff;
65 dst[0] = 0xff;
66 }
67 if ((count == 2) && dst[2] & 0x80) {
68 dst[1] = 0xff;
69 dst[0] = 0xff;
70 }
71#endif
72}
73
74static struct mem_access user_mem_access = {
75 copy_from_user,
76 copy_to_user,
77};
78
79static unsigned long copy_from_kernel_wrapper(void *dst, const void __user *src,
80 unsigned long cnt)
81{
82 return copy_from_kernel_nofault(dst, (const void __force *)src, cnt);
83}
84
85static unsigned long copy_to_kernel_wrapper(void __user *dst, const void *src,
86 unsigned long cnt)
87{
88 return copy_to_kernel_nofault((void __force *)dst, src, cnt);
89}
90
91static struct mem_access kernel_mem_access = {
92 copy_from_kernel_wrapper,
93 copy_to_kernel_wrapper,
94};
95
96/*
97 * handle an instruction that does an unaligned memory access by emulating the
98 * desired behaviour
99 * - note that PC _may not_ point to the faulting instruction
100 * (if that instruction is in a branch delay slot)
101 * - return 0 if emulation okay, -EFAULT on existential error
102 */
103static int handle_unaligned_ins(insn_size_t instruction, struct pt_regs *regs,
104 struct mem_access *ma)
105{
106 int ret, index, count;
107 unsigned long *rm, *rn;
108 unsigned char *src, *dst;
109 unsigned char __user *srcu, *dstu;
110
111 index = (instruction>>8)&15; /* 0x0F00 */
112 rn = ®s->regs[index];
113
114 index = (instruction>>4)&15; /* 0x00F0 */
115 rm = ®s->regs[index];
116
117 count = 1<<(instruction&3);
118
119 switch (count) {
120 case 1: inc_unaligned_byte_access(); break;
121 case 2: inc_unaligned_word_access(); break;
122 case 4: inc_unaligned_dword_access(); break;
123 case 8: inc_unaligned_multi_access(); break;
124 }
125
126 ret = -EFAULT;
127 switch (instruction>>12) {
128 case 0: /* mov.[bwl] to/from memory via r0+rn */
129 if (instruction & 8) {
130 /* from memory */
131 srcu = (unsigned char __user *)*rm;
132 srcu += regs->regs[0];
133 dst = (unsigned char *)rn;
134 *(unsigned long *)dst = 0;
135
136#if !defined(__LITTLE_ENDIAN__)
137 dst += 4-count;
138#endif
139 if (ma->from(dst, srcu, count))
140 goto fetch_fault;
141
142 sign_extend(count, dst);
143 } else {
144 /* to memory */
145 src = (unsigned char *)rm;
146#if !defined(__LITTLE_ENDIAN__)
147 src += 4-count;
148#endif
149 dstu = (unsigned char __user *)*rn;
150 dstu += regs->regs[0];
151
152 if (ma->to(dstu, src, count))
153 goto fetch_fault;
154 }
155 ret = 0;
156 break;
157
158 case 1: /* mov.l Rm,@(disp,Rn) */
159 src = (unsigned char*) rm;
160 dstu = (unsigned char __user *)*rn;
161 dstu += (instruction&0x000F)<<2;
162
163 if (ma->to(dstu, src, 4))
164 goto fetch_fault;
165 ret = 0;
166 break;
167
168 case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
169 if (instruction & 4)
170 *rn -= count;
171 src = (unsigned char*) rm;
172 dstu = (unsigned char __user *)*rn;
173#if !defined(__LITTLE_ENDIAN__)
174 src += 4-count;
175#endif
176 if (ma->to(dstu, src, count))
177 goto fetch_fault;
178 ret = 0;
179 break;
180
181 case 5: /* mov.l @(disp,Rm),Rn */
182 srcu = (unsigned char __user *)*rm;
183 srcu += (instruction & 0x000F) << 2;
184 dst = (unsigned char *)rn;
185 *(unsigned long *)dst = 0;
186
187 if (ma->from(dst, srcu, 4))
188 goto fetch_fault;
189 ret = 0;
190 break;
191
192 case 6: /* mov.[bwl] from memory, possibly with post-increment */
193 srcu = (unsigned char __user *)*rm;
194 if (instruction & 4)
195 *rm += count;
196 dst = (unsigned char*) rn;
197 *(unsigned long*)dst = 0;
198
199#if !defined(__LITTLE_ENDIAN__)
200 dst += 4-count;
201#endif
202 if (ma->from(dst, srcu, count))
203 goto fetch_fault;
204 sign_extend(count, dst);
205 ret = 0;
206 break;
207
208 case 8:
209 switch ((instruction&0xFF00)>>8) {
210 case 0x81: /* mov.w R0,@(disp,Rn) */
211 src = (unsigned char *) ®s->regs[0];
212#if !defined(__LITTLE_ENDIAN__)
213 src += 2;
214#endif
215 dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
216 dstu += (instruction & 0x000F) << 1;
217
218 if (ma->to(dstu, src, 2))
219 goto fetch_fault;
220 ret = 0;
221 break;
222
223 case 0x85: /* mov.w @(disp,Rm),R0 */
224 srcu = (unsigned char __user *)*rm;
225 srcu += (instruction & 0x000F) << 1;
226 dst = (unsigned char *) ®s->regs[0];
227 *(unsigned long *)dst = 0;
228
229#if !defined(__LITTLE_ENDIAN__)
230 dst += 2;
231#endif
232 if (ma->from(dst, srcu, 2))
233 goto fetch_fault;
234 sign_extend(2, dst);
235 ret = 0;
236 break;
237 }
238 break;
239
240 case 9: /* mov.w @(disp,PC),Rn */
241 srcu = (unsigned char __user *)regs->pc;
242 srcu += 4;
243 srcu += (instruction & 0x00FF) << 1;
244 dst = (unsigned char *)rn;
245 *(unsigned long *)dst = 0;
246
247#if !defined(__LITTLE_ENDIAN__)
248 dst += 2;
249#endif
250
251 if (ma->from(dst, srcu, 2))
252 goto fetch_fault;
253 sign_extend(2, dst);
254 ret = 0;
255 break;
256
257 case 0xd: /* mov.l @(disp,PC),Rn */
258 srcu = (unsigned char __user *)(regs->pc & ~0x3);
259 srcu += 4;
260 srcu += (instruction & 0x00FF) << 2;
261 dst = (unsigned char *)rn;
262 *(unsigned long *)dst = 0;
263
264 if (ma->from(dst, srcu, 4))
265 goto fetch_fault;
266 ret = 0;
267 break;
268 }
269 return ret;
270
271 fetch_fault:
272 /* Argh. Address not only misaligned but also non-existent.
273 * Raise an EFAULT and see if it's trapped
274 */
275 die_if_no_fixup("Fault in unaligned fixup", regs, 0);
276 return -EFAULT;
277}
278
279/*
280 * emulate the instruction in the delay slot
281 * - fetches the instruction from PC+2
282 */
283static inline int handle_delayslot(struct pt_regs *regs,
284 insn_size_t old_instruction,
285 struct mem_access *ma)
286{
287 insn_size_t instruction;
288 void __user *addr = (void __user *)(regs->pc +
289 instruction_size(old_instruction));
290
291 if (copy_from_user(&instruction, addr, sizeof(instruction))) {
292 /* the instruction-fetch faulted */
293 if (user_mode(regs))
294 return -EFAULT;
295
296 /* kernel */
297 die("delay-slot-insn faulting in handle_unaligned_delayslot",
298 regs, 0);
299 }
300
301 return handle_unaligned_ins(instruction, regs, ma);
302}
303
304/*
305 * handle an instruction that does an unaligned memory access
306 * - have to be careful of branch delay-slot instructions that fault
307 * SH3:
308 * - if the branch would be taken PC points to the branch
309 * - if the branch would not be taken, PC points to delay-slot
310 * SH4:
311 * - PC always points to delayed branch
312 * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
313 */
314
315/* Macros to determine offset from current PC for branch instructions */
316/* Explicit type coercion is used to force sign extension where needed */
317#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
318#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
319
320int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
321 struct mem_access *ma, int expected,
322 unsigned long address)
323{
324 u_int rm;
325 int ret, index;
326
327 /*
328 * XXX: We can't handle mixed 16/32-bit instructions yet
329 */
330 if (instruction_size(instruction) != 2)
331 return -EINVAL;
332
333 index = (instruction>>8)&15; /* 0x0F00 */
334 rm = regs->regs[index];
335
336 /*
337 * Log the unexpected fixups, and then pass them on to perf.
338 *
339 * We intentionally don't report the expected cases to perf as
340 * otherwise the trapped I/O case will skew the results too much
341 * to be useful.
342 */
343 if (!expected) {
344 unaligned_fixups_notify(current, instruction, regs);
345 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1,
346 regs, address);
347 }
348
349 ret = -EFAULT;
350 switch (instruction&0xF000) {
351 case 0x0000:
352 if (instruction==0x000B) {
353 /* rts */
354 ret = handle_delayslot(regs, instruction, ma);
355 if (ret==0)
356 regs->pc = regs->pr;
357 }
358 else if ((instruction&0x00FF)==0x0023) {
359 /* braf @Rm */
360 ret = handle_delayslot(regs, instruction, ma);
361 if (ret==0)
362 regs->pc += rm + 4;
363 }
364 else if ((instruction&0x00FF)==0x0003) {
365 /* bsrf @Rm */
366 ret = handle_delayslot(regs, instruction, ma);
367 if (ret==0) {
368 regs->pr = regs->pc + 4;
369 regs->pc += rm + 4;
370 }
371 }
372 else {
373 /* mov.[bwl] to/from memory via r0+rn */
374 goto simple;
375 }
376 break;
377
378 case 0x1000: /* mov.l Rm,@(disp,Rn) */
379 goto simple;
380
381 case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
382 goto simple;
383
384 case 0x4000:
385 if ((instruction&0x00FF)==0x002B) {
386 /* jmp @Rm */
387 ret = handle_delayslot(regs, instruction, ma);
388 if (ret==0)
389 regs->pc = rm;
390 }
391 else if ((instruction&0x00FF)==0x000B) {
392 /* jsr @Rm */
393 ret = handle_delayslot(regs, instruction, ma);
394 if (ret==0) {
395 regs->pr = regs->pc + 4;
396 regs->pc = rm;
397 }
398 }
399 else {
400 /* mov.[bwl] to/from memory via r0+rn */
401 goto simple;
402 }
403 break;
404
405 case 0x5000: /* mov.l @(disp,Rm),Rn */
406 goto simple;
407
408 case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
409 goto simple;
410
411 case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
412 switch (instruction&0x0F00) {
413 case 0x0100: /* mov.w R0,@(disp,Rm) */
414 goto simple;
415 case 0x0500: /* mov.w @(disp,Rm),R0 */
416 goto simple;
417 case 0x0B00: /* bf lab - no delayslot*/
418 ret = 0;
419 break;
420 case 0x0F00: /* bf/s lab */
421 ret = handle_delayslot(regs, instruction, ma);
422 if (ret==0) {
423#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
424 if ((regs->sr & 0x00000001) != 0)
425 regs->pc += 4; /* next after slot */
426 else
427#endif
428 regs->pc += SH_PC_8BIT_OFFSET(instruction);
429 }
430 break;
431 case 0x0900: /* bt lab - no delayslot */
432 ret = 0;
433 break;
434 case 0x0D00: /* bt/s lab */
435 ret = handle_delayslot(regs, instruction, ma);
436 if (ret==0) {
437#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
438 if ((regs->sr & 0x00000001) == 0)
439 regs->pc += 4; /* next after slot */
440 else
441#endif
442 regs->pc += SH_PC_8BIT_OFFSET(instruction);
443 }
444 break;
445 }
446 break;
447
448 case 0x9000: /* mov.w @(disp,Rm),Rn */
449 goto simple;
450
451 case 0xA000: /* bra label */
452 ret = handle_delayslot(regs, instruction, ma);
453 if (ret==0)
454 regs->pc += SH_PC_12BIT_OFFSET(instruction);
455 break;
456
457 case 0xB000: /* bsr label */
458 ret = handle_delayslot(regs, instruction, ma);
459 if (ret==0) {
460 regs->pr = regs->pc + 4;
461 regs->pc += SH_PC_12BIT_OFFSET(instruction);
462 }
463 break;
464
465 case 0xD000: /* mov.l @(disp,Rm),Rn */
466 goto simple;
467 }
468 return ret;
469
470 /* handle non-delay-slot instruction */
471 simple:
472 ret = handle_unaligned_ins(instruction, regs, ma);
473 if (ret==0)
474 regs->pc += instruction_size(instruction);
475 return ret;
476}
477
478/*
479 * Handle various address error exceptions:
480 * - instruction address error:
481 * misaligned PC
482 * PC >= 0x80000000 in user mode
483 * - data address error (read and write)
484 * misaligned data access
485 * access to >= 0x80000000 is user mode
486 * Unfortuntaly we can't distinguish between instruction address error
487 * and data address errors caused by read accesses.
488 */
489asmlinkage void do_address_error(struct pt_regs *regs,
490 unsigned long writeaccess,
491 unsigned long address)
492{
493 unsigned long error_code = 0;
494 insn_size_t instruction;
495 int tmp;
496
497 /* Intentional ifdef */
498#ifdef CONFIG_CPU_HAS_SR_RB
499 error_code = lookup_exception_vector();
500#endif
501
502 if (user_mode(regs)) {
503 int si_code = BUS_ADRERR;
504 unsigned int user_action;
505
506 local_irq_enable();
507 inc_unaligned_user_access();
508
509 if (copy_from_user(&instruction, (insn_size_t __user *)(regs->pc & ~1),
510 sizeof(instruction))) {
511 goto uspace_segv;
512 }
513
514 /* shout about userspace fixups */
515 unaligned_fixups_notify(current, instruction, regs);
516
517 user_action = unaligned_user_action();
518 if (user_action & UM_FIXUP)
519 goto fixup;
520 if (user_action & UM_SIGNAL)
521 goto uspace_segv;
522 else {
523 /* ignore */
524 regs->pc += instruction_size(instruction);
525 return;
526 }
527
528fixup:
529 /* bad PC is not something we can fix */
530 if (regs->pc & 1) {
531 si_code = BUS_ADRALN;
532 goto uspace_segv;
533 }
534
535 tmp = handle_unaligned_access(instruction, regs,
536 &user_mem_access, 0,
537 address);
538
539 if (tmp == 0)
540 return; /* sorted */
541uspace_segv:
542 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
543 "access (PC %lx PR %lx)\n", current->comm, regs->pc,
544 regs->pr);
545
546 force_sig_fault(SIGBUS, si_code, (void __user *)address);
547 } else {
548 inc_unaligned_kernel_access();
549
550 if (regs->pc & 1)
551 die("unaligned program counter", regs, error_code);
552
553 if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc),
554 sizeof(instruction))) {
555 /* Argh. Fault on the instruction itself.
556 This should never happen non-SMP
557 */
558 die("insn faulting in do_address_error", regs, 0);
559 }
560
561 unaligned_fixups_notify(current, instruction, regs);
562
563 handle_unaligned_access(instruction, regs, &kernel_mem_access,
564 0, address);
565 }
566}
567
568#ifdef CONFIG_SH_DSP
569/*
570 * SH-DSP support gerg@snapgear.com.
571 */
572static int is_dsp_inst(struct pt_regs *regs)
573{
574 unsigned short inst = 0;
575
576 /*
577 * Safe guard if DSP mode is already enabled or we're lacking
578 * the DSP altogether.
579 */
580 if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
581 return 0;
582
583 get_user(inst, ((unsigned short *) regs->pc));
584
585 inst &= 0xf000;
586
587 /* Check for any type of DSP or support instruction */
588 if ((inst == 0xf000) || (inst == 0x4000))
589 return 1;
590
591 return 0;
592}
593#else
594static inline int is_dsp_inst(struct pt_regs *regs) { return 0; }
595#endif /* CONFIG_SH_DSP */
596
597#ifdef CONFIG_CPU_SH2A
598asmlinkage void do_divide_error(unsigned long r4)
599{
600 int code;
601
602 switch (r4) {
603 case TRAP_DIVZERO_ERROR:
604 code = FPE_INTDIV;
605 break;
606 case TRAP_DIVOVF_ERROR:
607 code = FPE_INTOVF;
608 break;
609 default:
610 /* Let gcc know unhandled cases don't make it past here */
611 return;
612 }
613 force_sig_fault(SIGFPE, code, NULL);
614}
615#endif
616
617asmlinkage void do_reserved_inst(void)
618{
619 struct pt_regs *regs = current_pt_regs();
620 unsigned long error_code;
621
622#ifdef CONFIG_SH_FPU_EMU
623 unsigned short inst = 0;
624 int err;
625
626 get_user(inst, (unsigned short __user *)regs->pc);
627
628 err = do_fpu_inst(inst, regs);
629 if (!err) {
630 regs->pc += instruction_size(inst);
631 return;
632 }
633 /* not a FPU inst. */
634#endif
635
636#ifdef CONFIG_SH_DSP
637 /* Check if it's a DSP instruction */
638 if (is_dsp_inst(regs)) {
639 /* Enable DSP mode, and restart instruction. */
640 regs->sr |= SR_DSP;
641 /* Save DSP mode */
642 current->thread.dsp_status.status |= SR_DSP;
643 return;
644 }
645#endif
646
647 error_code = lookup_exception_vector();
648
649 local_irq_enable();
650 force_sig(SIGILL);
651 die_if_no_fixup("reserved instruction", regs, error_code);
652}
653
654#ifdef CONFIG_SH_FPU_EMU
655static int emulate_branch(unsigned short inst, struct pt_regs *regs)
656{
657 /*
658 * bfs: 8fxx: PC+=d*2+4;
659 * bts: 8dxx: PC+=d*2+4;
660 * bra: axxx: PC+=D*2+4;
661 * bsr: bxxx: PC+=D*2+4 after PR=PC+4;
662 * braf:0x23: PC+=Rn*2+4;
663 * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
664 * jmp: 4x2b: PC=Rn;
665 * jsr: 4x0b: PC=Rn after PR=PC+4;
666 * rts: 000b: PC=PR;
667 */
668 if (((inst & 0xf000) == 0xb000) || /* bsr */
669 ((inst & 0xf0ff) == 0x0003) || /* bsrf */
670 ((inst & 0xf0ff) == 0x400b)) /* jsr */
671 regs->pr = regs->pc + 4;
672
673 if ((inst & 0xfd00) == 0x8d00) { /* bfs, bts */
674 regs->pc += SH_PC_8BIT_OFFSET(inst);
675 return 0;
676 }
677
678 if ((inst & 0xe000) == 0xa000) { /* bra, bsr */
679 regs->pc += SH_PC_12BIT_OFFSET(inst);
680 return 0;
681 }
682
683 if ((inst & 0xf0df) == 0x0003) { /* braf, bsrf */
684 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
685 return 0;
686 }
687
688 if ((inst & 0xf0df) == 0x400b) { /* jmp, jsr */
689 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
690 return 0;
691 }
692
693 if ((inst & 0xffff) == 0x000b) { /* rts */
694 regs->pc = regs->pr;
695 return 0;
696 }
697
698 return 1;
699}
700#endif
701
702asmlinkage void do_illegal_slot_inst(void)
703{
704 struct pt_regs *regs = current_pt_regs();
705 unsigned long inst;
706
707 if (kprobe_handle_illslot(regs->pc) == 0)
708 return;
709
710#ifdef CONFIG_SH_FPU_EMU
711 get_user(inst, (unsigned short __user *)regs->pc + 1);
712 if (!do_fpu_inst(inst, regs)) {
713 get_user(inst, (unsigned short __user *)regs->pc);
714 if (!emulate_branch(inst, regs))
715 return;
716 /* fault in branch.*/
717 }
718 /* not a FPU inst. */
719#endif
720
721 inst = lookup_exception_vector();
722
723 local_irq_enable();
724 force_sig(SIGILL);
725 die_if_no_fixup("illegal slot instruction", regs, inst);
726}
727
728asmlinkage void do_exception_error(void)
729{
730 long ex;
731
732 ex = lookup_exception_vector();
733 die_if_kernel("exception", current_pt_regs(), ex);
734}
735
736void per_cpu_trap_init(void)
737{
738 extern void *vbr_base;
739
740 /* NOTE: The VBR value should be at P1
741 (or P2, virtural "fixed" address space).
742 It's definitely should not in physical address. */
743
744 asm volatile("ldc %0, vbr"
745 : /* no output */
746 : "r" (&vbr_base)
747 : "memory");
748
749 /* disable exception blocking now when the vbr has been setup */
750 clear_bl_bit();
751}
752
753void *set_exception_table_vec(unsigned int vec, void *handler)
754{
755 extern void *exception_handling_table[];
756 void *old_handler;
757
758 old_handler = exception_handling_table[vec];
759 exception_handling_table[vec] = handler;
760 return old_handler;
761}
762
763void __init trap_init(void)
764{
765 set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
766 set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
767
768#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
769 defined(CONFIG_SH_FPU_EMU)
770 /*
771 * For SH-4 lacking an FPU, treat floating point instructions as
772 * reserved. They'll be handled in the math-emu case, or faulted on
773 * otherwise.
774 */
775 set_exception_table_evt(0x800, do_reserved_inst);
776 set_exception_table_evt(0x820, do_illegal_slot_inst);
777#elif defined(CONFIG_SH_FPU)
778 set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
779 set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
780#endif
781
782#ifdef CONFIG_CPU_SH2
783 set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
784#endif
785#ifdef CONFIG_CPU_SH2A
786 set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
787 set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
788#ifdef CONFIG_SH_FPU
789 set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
790#endif
791#endif
792
793#ifdef TRAP_UBC
794 set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler);
795#endif
796}