1 /*
2 * linux/arch/m32r/kernel/ptrace.c
3 *
4 * Copyright (C) 2002 Hirokazu Takata, Takeo Takahashi
5 * Copyright (C) 2004 Hirokazu Takata, Kei Sakamoto
6 *
7 * Original x86 implementation:
8 * By Ross Biro 1/23/92
9 * edited by Linus Torvalds
10 *
11 * Some code taken from sh version:
12 * Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
13 * Some code taken from arm version:
14 * Copyright (C) 2000 Russell King
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/mm.h>
20 #include <linux/err.h>
21 #include <linux/smp.h>
22 #include <linux/errno.h>
23 #include <linux/ptrace.h>
24 #include <linux/user.h>
25 #include <linux/string.h>
26 #include <linux/signal.h>
27
28 #include <asm/cacheflush.h>
29 #include <asm/io.h>
30 #include <asm/uaccess.h>
31 #include <asm/pgtable.h>
32 #include <asm/processor.h>
33 #include <asm/mmu_context.h>
34
35 /*
36 * This routine will get a word off of the process kernel stack.
37 */
38 static inline unsigned long int
get_stack_long(struct task_struct * task,int offset)39 get_stack_long(struct task_struct *task, int offset)
40 {
41 unsigned long *stack;
42
43 stack = (unsigned long *)task_pt_regs(task);
44
45 return stack[offset];
46 }
47
48 /*
49 * This routine will put a word on the process kernel stack.
50 */
51 static inline int
put_stack_long(struct task_struct * task,int offset,unsigned long data)52 put_stack_long(struct task_struct *task, int offset, unsigned long data)
53 {
54 unsigned long *stack;
55
56 stack = (unsigned long *)task_pt_regs(task);
57 stack[offset] = data;
58
59 return 0;
60 }
61
62 static int reg_offset[] = {
63 PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7,
64 PT_R8, PT_R9, PT_R10, PT_R11, PT_R12, PT_FP, PT_LR, PT_SPU,
65 };
66
67 /*
68 * Read the word at offset "off" into the "struct user". We
69 * actually access the pt_regs stored on the kernel stack.
70 */
ptrace_read_user(struct task_struct * tsk,unsigned long off,unsigned long __user * data)71 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
72 unsigned long __user *data)
73 {
74 unsigned long tmp;
75 #ifndef NO_FPU
76 struct user * dummy = NULL;
77 #endif
78
79 if ((off & 3) || off > sizeof(struct user) - 3)
80 return -EIO;
81
82 off >>= 2;
83 switch (off) {
84 case PT_EVB:
85 __asm__ __volatile__ (
86 "mvfc %0, cr5 \n\t"
87 : "=r" (tmp)
88 );
89 break;
90 case PT_CBR: {
91 unsigned long psw;
92 psw = get_stack_long(tsk, PT_PSW);
93 tmp = ((psw >> 8) & 1);
94 }
95 break;
96 case PT_PSW: {
97 unsigned long psw, bbpsw;
98 psw = get_stack_long(tsk, PT_PSW);
99 bbpsw = get_stack_long(tsk, PT_BBPSW);
100 tmp = ((psw >> 8) & 0xff) | ((bbpsw & 0xff) << 8);
101 }
102 break;
103 case PT_PC:
104 tmp = get_stack_long(tsk, PT_BPC);
105 break;
106 case PT_BPC:
107 off = PT_BBPC;
108 /* fall through */
109 default:
110 if (off < (sizeof(struct pt_regs) >> 2))
111 tmp = get_stack_long(tsk, off);
112 #ifndef NO_FPU
113 else if (off >= (long)(&dummy->fpu >> 2) &&
114 off < (long)(&dummy->u_fpvalid >> 2)) {
115 if (!tsk_used_math(tsk)) {
116 if (off == (long)(&dummy->fpu.fpscr >> 2))
117 tmp = FPSCR_INIT;
118 else
119 tmp = 0;
120 } else
121 tmp = ((long *)(&tsk->thread.fpu >> 2))
122 [off - (long)&dummy->fpu];
123 } else if (off == (long)(&dummy->u_fpvalid >> 2))
124 tmp = !!tsk_used_math(tsk);
125 #endif /* not NO_FPU */
126 else
127 tmp = 0;
128 }
129
130 return put_user(tmp, data);
131 }
132
ptrace_write_user(struct task_struct * tsk,unsigned long off,unsigned long data)133 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
134 unsigned long data)
135 {
136 int ret = -EIO;
137 #ifndef NO_FPU
138 struct user * dummy = NULL;
139 #endif
140
141 if ((off & 3) || off > sizeof(struct user) - 3)
142 return -EIO;
143
144 off >>= 2;
145 switch (off) {
146 case PT_EVB:
147 case PT_BPC:
148 case PT_SPI:
149 /* We don't allow to modify evb. */
150 ret = 0;
151 break;
152 case PT_PSW:
153 case PT_CBR: {
154 /* We allow to modify only cbr in psw */
155 unsigned long psw;
156 psw = get_stack_long(tsk, PT_PSW);
157 psw = (psw & ~0x100) | ((data & 1) << 8);
158 ret = put_stack_long(tsk, PT_PSW, psw);
159 }
160 break;
161 case PT_PC:
162 off = PT_BPC;
163 data &= ~1;
164 /* fall through */
165 default:
166 if (off < (sizeof(struct pt_regs) >> 2))
167 ret = put_stack_long(tsk, off, data);
168 #ifndef NO_FPU
169 else if (off >= (long)(&dummy->fpu >> 2) &&
170 off < (long)(&dummy->u_fpvalid >> 2)) {
171 set_stopped_child_used_math(tsk);
172 ((long *)&tsk->thread.fpu)
173 [off - (long)&dummy->fpu] = data;
174 ret = 0;
175 } else if (off == (long)(&dummy->u_fpvalid >> 2)) {
176 conditional_stopped_child_used_math(data, tsk);
177 ret = 0;
178 }
179 #endif /* not NO_FPU */
180 break;
181 }
182
183 return ret;
184 }
185
186 /*
187 * Get all user integer registers.
188 */
ptrace_getregs(struct task_struct * tsk,void __user * uregs)189 static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
190 {
191 struct pt_regs *regs = task_pt_regs(tsk);
192
193 return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
194 }
195
196 /*
197 * Set all user integer registers.
198 */
ptrace_setregs(struct task_struct * tsk,void __user * uregs)199 static int ptrace_setregs(struct task_struct *tsk, void __user *uregs)
200 {
201 struct pt_regs newregs;
202 int ret;
203
204 ret = -EFAULT;
205 if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
206 struct pt_regs *regs = task_pt_regs(tsk);
207 *regs = newregs;
208 ret = 0;
209 }
210
211 return ret;
212 }
213
214
215 static inline int
check_condition_bit(struct task_struct * child)216 check_condition_bit(struct task_struct *child)
217 {
218 return (int)((get_stack_long(child, PT_PSW) >> 8) & 1);
219 }
220
221 static int
check_condition_src(unsigned long op,unsigned long regno1,unsigned long regno2,struct task_struct * child)222 check_condition_src(unsigned long op, unsigned long regno1,
223 unsigned long regno2, struct task_struct *child)
224 {
225 unsigned long reg1, reg2;
226
227 reg2 = get_stack_long(child, reg_offset[regno2]);
228
229 switch (op) {
230 case 0x0: /* BEQ */
231 reg1 = get_stack_long(child, reg_offset[regno1]);
232 return reg1 == reg2;
233 case 0x1: /* BNE */
234 reg1 = get_stack_long(child, reg_offset[regno1]);
235 return reg1 != reg2;
236 case 0x8: /* BEQZ */
237 return reg2 == 0;
238 case 0x9: /* BNEZ */
239 return reg2 != 0;
240 case 0xa: /* BLTZ */
241 return (int)reg2 < 0;
242 case 0xb: /* BGEZ */
243 return (int)reg2 >= 0;
244 case 0xc: /* BLEZ */
245 return (int)reg2 <= 0;
246 case 0xd: /* BGTZ */
247 return (int)reg2 > 0;
248 default:
249 /* never reached */
250 return 0;
251 }
252 }
253
254 static void
compute_next_pc_for_16bit_insn(unsigned long insn,unsigned long pc,unsigned long * next_pc,struct task_struct * child)255 compute_next_pc_for_16bit_insn(unsigned long insn, unsigned long pc,
256 unsigned long *next_pc,
257 struct task_struct *child)
258 {
259 unsigned long op, op2, op3;
260 unsigned long disp;
261 unsigned long regno;
262 int parallel = 0;
263
264 if (insn & 0x00008000)
265 parallel = 1;
266 if (pc & 3)
267 insn &= 0x7fff; /* right slot */
268 else
269 insn >>= 16; /* left slot */
270
271 op = (insn >> 12) & 0xf;
272 op2 = (insn >> 8) & 0xf;
273 op3 = (insn >> 4) & 0xf;
274
275 if (op == 0x7) {
276 switch (op2) {
277 case 0xd: /* BNC */
278 case 0x9: /* BNCL */
279 if (!check_condition_bit(child)) {
280 disp = (long)(insn << 24) >> 22;
281 *next_pc = (pc & ~0x3) + disp;
282 return;
283 }
284 break;
285 case 0x8: /* BCL */
286 case 0xc: /* BC */
287 if (check_condition_bit(child)) {
288 disp = (long)(insn << 24) >> 22;
289 *next_pc = (pc & ~0x3) + disp;
290 return;
291 }
292 break;
293 case 0xe: /* BL */
294 case 0xf: /* BRA */
295 disp = (long)(insn << 24) >> 22;
296 *next_pc = (pc & ~0x3) + disp;
297 return;
298 break;
299 }
300 } else if (op == 0x1) {
301 switch (op2) {
302 case 0x0:
303 if (op3 == 0xf) { /* TRAP */
304 #if 1
305 /* pass through */
306 #else
307 /* kernel space is not allowed as next_pc */
308 unsigned long evb;
309 unsigned long trapno;
310 trapno = insn & 0xf;
311 __asm__ __volatile__ (
312 "mvfc %0, cr5\n"
313 :"=r"(evb)
314 :
315 );
316 *next_pc = evb + (trapno << 2);
317 return;
318 #endif
319 } else if (op3 == 0xd) { /* RTE */
320 *next_pc = get_stack_long(child, PT_BPC);
321 return;
322 }
323 break;
324 case 0xc: /* JC */
325 if (op3 == 0xc && check_condition_bit(child)) {
326 regno = insn & 0xf;
327 *next_pc = get_stack_long(child,
328 reg_offset[regno]);
329 return;
330 }
331 break;
332 case 0xd: /* JNC */
333 if (op3 == 0xc && !check_condition_bit(child)) {
334 regno = insn & 0xf;
335 *next_pc = get_stack_long(child,
336 reg_offset[regno]);
337 return;
338 }
339 break;
340 case 0xe: /* JL */
341 case 0xf: /* JMP */
342 if (op3 == 0xc) { /* JMP */
343 regno = insn & 0xf;
344 *next_pc = get_stack_long(child,
345 reg_offset[regno]);
346 return;
347 }
348 break;
349 }
350 }
351 if (parallel)
352 *next_pc = pc + 4;
353 else
354 *next_pc = pc + 2;
355 }
356
357 static void
compute_next_pc_for_32bit_insn(unsigned long insn,unsigned long pc,unsigned long * next_pc,struct task_struct * child)358 compute_next_pc_for_32bit_insn(unsigned long insn, unsigned long pc,
359 unsigned long *next_pc,
360 struct task_struct *child)
361 {
362 unsigned long op;
363 unsigned long op2;
364 unsigned long disp;
365 unsigned long regno1, regno2;
366
367 op = (insn >> 28) & 0xf;
368 if (op == 0xf) { /* branch 24-bit relative */
369 op2 = (insn >> 24) & 0xf;
370 switch (op2) {
371 case 0xd: /* BNC */
372 case 0x9: /* BNCL */
373 if (!check_condition_bit(child)) {
374 disp = (long)(insn << 8) >> 6;
375 *next_pc = (pc & ~0x3) + disp;
376 return;
377 }
378 break;
379 case 0x8: /* BCL */
380 case 0xc: /* BC */
381 if (check_condition_bit(child)) {
382 disp = (long)(insn << 8) >> 6;
383 *next_pc = (pc & ~0x3) + disp;
384 return;
385 }
386 break;
387 case 0xe: /* BL */
388 case 0xf: /* BRA */
389 disp = (long)(insn << 8) >> 6;
390 *next_pc = (pc & ~0x3) + disp;
391 return;
392 }
393 } else if (op == 0xb) { /* branch 16-bit relative */
394 op2 = (insn >> 20) & 0xf;
395 switch (op2) {
396 case 0x0: /* BEQ */
397 case 0x1: /* BNE */
398 case 0x8: /* BEQZ */
399 case 0x9: /* BNEZ */
400 case 0xa: /* BLTZ */
401 case 0xb: /* BGEZ */
402 case 0xc: /* BLEZ */
403 case 0xd: /* BGTZ */
404 regno1 = ((insn >> 24) & 0xf);
405 regno2 = ((insn >> 16) & 0xf);
406 if (check_condition_src(op2, regno1, regno2, child)) {
407 disp = (long)(insn << 16) >> 14;
408 *next_pc = (pc & ~0x3) + disp;
409 return;
410 }
411 break;
412 }
413 }
414 *next_pc = pc + 4;
415 }
416
417 static inline void
compute_next_pc(unsigned long insn,unsigned long pc,unsigned long * next_pc,struct task_struct * child)418 compute_next_pc(unsigned long insn, unsigned long pc,
419 unsigned long *next_pc, struct task_struct *child)
420 {
421 if (insn & 0x80000000)
422 compute_next_pc_for_32bit_insn(insn, pc, next_pc, child);
423 else
424 compute_next_pc_for_16bit_insn(insn, pc, next_pc, child);
425 }
426
427 static int
register_debug_trap(struct task_struct * child,unsigned long next_pc,unsigned long next_insn,unsigned long * code)428 register_debug_trap(struct task_struct *child, unsigned long next_pc,
429 unsigned long next_insn, unsigned long *code)
430 {
431 struct debug_trap *p = &child->thread.debug_trap;
432 unsigned long addr = next_pc & ~3;
433
434 if (p->nr_trap == MAX_TRAPS) {
435 printk("kernel BUG at %s %d: p->nr_trap = %d\n",
436 __FILE__, __LINE__, p->nr_trap);
437 return -1;
438 }
439 p->addr[p->nr_trap] = addr;
440 p->insn[p->nr_trap] = next_insn;
441 p->nr_trap++;
442 if (next_pc & 3) {
443 *code = (next_insn & 0xffff0000) | 0x10f1;
444 /* xxx --> TRAP1 */
445 } else {
446 if ((next_insn & 0x80000000) || (next_insn & 0x8000)) {
447 *code = 0x10f17000;
448 /* TRAP1 --> NOP */
449 } else {
450 *code = (next_insn & 0xffff) | 0x10f10000;
451 /* TRAP1 --> xxx */
452 }
453 }
454 return 0;
455 }
456
457 static int
unregister_debug_trap(struct task_struct * child,unsigned long addr,unsigned long * code)458 unregister_debug_trap(struct task_struct *child, unsigned long addr,
459 unsigned long *code)
460 {
461 struct debug_trap *p = &child->thread.debug_trap;
462 int i;
463
464 /* Search debug trap entry. */
465 for (i = 0; i < p->nr_trap; i++) {
466 if (p->addr[i] == addr)
467 break;
468 }
469 if (i >= p->nr_trap) {
470 /* The trap may be requested from debugger.
471 * ptrace should do nothing in this case.
472 */
473 return 0;
474 }
475
476 /* Recover original instruction code. */
477 *code = p->insn[i];
478
479 /* Shift debug trap entries. */
480 while (i < p->nr_trap - 1) {
481 p->insn[i] = p->insn[i + 1];
482 p->addr[i] = p->addr[i + 1];
483 i++;
484 }
485 p->nr_trap--;
486 return 1;
487 }
488
489 static void
unregister_all_debug_traps(struct task_struct * child)490 unregister_all_debug_traps(struct task_struct *child)
491 {
492 struct debug_trap *p = &child->thread.debug_trap;
493 int i;
494
495 for (i = 0; i < p->nr_trap; i++)
496 access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]), 1);
497 p->nr_trap = 0;
498 }
499
500 static inline void
invalidate_cache(void)501 invalidate_cache(void)
502 {
503 #if defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP)
504
505 _flush_cache_copyback_all();
506
507 #else /* ! CONFIG_CHIP_M32700 */
508
509 /* Invalidate cache */
510 __asm__ __volatile__ (
511 "ldi r0, #-1 \n\t"
512 "ldi r1, #0 \n\t"
513 "stb r1, @r0 ; cache off \n\t"
514 "; \n\t"
515 "ldi r0, #-2 \n\t"
516 "ldi r1, #1 \n\t"
517 "stb r1, @r0 ; cache invalidate \n\t"
518 ".fillinsn \n"
519 "0: \n\t"
520 "ldb r1, @r0 ; invalidate check \n\t"
521 "bnez r1, 0b \n\t"
522 "; \n\t"
523 "ldi r0, #-1 \n\t"
524 "ldi r1, #1 \n\t"
525 "stb r1, @r0 ; cache on \n\t"
526 : : : "r0", "r1", "memory"
527 );
528 /* FIXME: copying-back d-cache and invalidating i-cache are needed.
529 */
530 #endif /* CONFIG_CHIP_M32700 */
531 }
532
533 /* Embed a debug trap (TRAP1) code */
534 static int
embed_debug_trap(struct task_struct * child,unsigned long next_pc)535 embed_debug_trap(struct task_struct *child, unsigned long next_pc)
536 {
537 unsigned long next_insn, code;
538 unsigned long addr = next_pc & ~3;
539
540 if (access_process_vm(child, addr, &next_insn, sizeof(next_insn), 0)
541 != sizeof(next_insn)) {
542 return -1; /* error */
543 }
544
545 /* Set a trap code. */
546 if (register_debug_trap(child, next_pc, next_insn, &code)) {
547 return -1; /* error */
548 }
549 if (access_process_vm(child, addr, &code, sizeof(code), 1)
550 != sizeof(code)) {
551 return -1; /* error */
552 }
553 return 0; /* success */
554 }
555
556 void
withdraw_debug_trap(struct pt_regs * regs)557 withdraw_debug_trap(struct pt_regs *regs)
558 {
559 unsigned long addr;
560 unsigned long code;
561
562 addr = (regs->bpc - 2) & ~3;
563 regs->bpc -= 2;
564 if (unregister_debug_trap(current, addr, &code)) {
565 access_process_vm(current, addr, &code, sizeof(code), 1);
566 invalidate_cache();
567 }
568 }
569
570 void
init_debug_traps(struct task_struct * child)571 init_debug_traps(struct task_struct *child)
572 {
573 struct debug_trap *p = &child->thread.debug_trap;
574 int i;
575 p->nr_trap = 0;
576 for (i = 0; i < MAX_TRAPS; i++) {
577 p->addr[i] = 0;
578 p->insn[i] = 0;
579 }
580 }
581
user_enable_single_step(struct task_struct * child)582 void user_enable_single_step(struct task_struct *child)
583 {
584 unsigned long next_pc;
585 unsigned long pc, insn;
586
587 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
588
589 /* Compute next pc. */
590 pc = get_stack_long(child, PT_BPC);
591
592 if (access_process_vm(child, pc&~3, &insn, sizeof(insn), 0)
593 != sizeof(insn))
594 return -EIO;
595
596 compute_next_pc(insn, pc, &next_pc, child);
597 if (next_pc & 0x80000000)
598 return -EIO;
599
600 if (embed_debug_trap(child, next_pc))
601 return -EIO;
602
603 invalidate_cache();
604 return 0;
605 }
606
user_disable_single_step(struct task_struct * child)607 void user_disable_single_step(struct task_struct *child)
608 {
609 unregister_all_debug_traps(child);
610 invalidate_cache();
611 }
612
613 /*
614 * Called by kernel/ptrace.c when detaching..
615 *
616 * Make sure single step bits etc are not set.
617 */
ptrace_disable(struct task_struct * child)618 void ptrace_disable(struct task_struct *child)
619 {
620 /* nothing to do.. */
621 }
622
623 long
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)624 arch_ptrace(struct task_struct *child, long request,
625 unsigned long addr, unsigned long data)
626 {
627 int ret;
628 unsigned long __user *datap = (unsigned long __user *) data;
629
630 switch (request) {
631 /*
632 * read word at location "addr" in the child process.
633 */
634 case PTRACE_PEEKTEXT:
635 case PTRACE_PEEKDATA:
636 ret = generic_ptrace_peekdata(child, addr, data);
637 break;
638
639 /*
640 * read the word at location addr in the USER area.
641 */
642 case PTRACE_PEEKUSR:
643 ret = ptrace_read_user(child, addr, datap);
644 break;
645
646 /*
647 * write the word at location addr.
648 */
649 case PTRACE_POKETEXT:
650 case PTRACE_POKEDATA:
651 ret = generic_ptrace_pokedata(child, addr, data);
652 if (ret == 0 && request == PTRACE_POKETEXT)
653 invalidate_cache();
654 break;
655
656 /*
657 * write the word at location addr in the USER area.
658 */
659 case PTRACE_POKEUSR:
660 ret = ptrace_write_user(child, addr, data);
661 break;
662
663 case PTRACE_GETREGS:
664 ret = ptrace_getregs(child, datap);
665 break;
666
667 case PTRACE_SETREGS:
668 ret = ptrace_setregs(child, datap);
669 break;
670
671 default:
672 ret = ptrace_request(child, request, addr, data);
673 break;
674 }
675
676 return ret;
677 }
678
679 /* notification of system call entry/exit
680 * - triggered by current->work.syscall_trace
681 */
do_syscall_trace(void)682 void do_syscall_trace(void)
683 {
684 if (!test_thread_flag(TIF_SYSCALL_TRACE))
685 return;
686 if (!(current->ptrace & PT_PTRACED))
687 return;
688 /* the 0x80 provides a way for the tracing parent to distinguish
689 between a syscall stop and SIGTRAP delivery */
690 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
691 ? 0x80 : 0));
692
693 /*
694 * this isn't the same as continuing with a signal, but it will do
695 * for normal use. strace only continues with a signal if the
696 * stopping signal is not SIGTRAP. -brl
697 */
698 if (current->exit_code) {
699 send_sig(current->exit_code, current, 1);
700 current->exit_code = 0;
701 }
702 }
703