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