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mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race
[linux/fpc-iii.git] / arch / m32r / kernel / ptrace.c
blobd702a5ca0f928e25286e90045a75aeebba076904
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/arch/m32r/kernel/ptrace.c
4 *
5 * Copyright (C) 2002 Hirokazu Takata, Takeo Takahashi
6 * Copyright (C) 2004 Hirokazu Takata, Kei Sakamoto
7 *
8 * Original x86 implementation:
9 * By Ross Biro 1/23/92
10 * edited by Linus Torvalds
11 *
12 * Some code taken from sh version:
13 * Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
14 * Some code taken from arm version:
15 * Copyright (C) 2000 Russell King
16 */
17
18 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/sched/task_stack.h>
21 #include <linux/mm.h>
22 #include <linux/err.h>
23 #include <linux/smp.h>
24 #include <linux/errno.h>
25 #include <linux/ptrace.h>
26 #include <linux/user.h>
27 #include <linux/string.h>
28 #include <linux/signal.h>
29
30 #include <asm/cacheflush.h>
31 #include <asm/io.h>
32 #include <linux/uaccess.h>
33 #include <asm/pgtable.h>
34 #include <asm/processor.h>
35 #include <asm/mmu_context.h>
36
37 /*
38 * This routine will get a word off of the process kernel stack.
39 */
40 static inline unsigned long int
41 get_stack_long(struct task_struct *task, int offset)
42 {
43 unsigned long *stack;
44
45 stack = (unsigned long *)task_pt_regs(task);
46
47 return stack[offset];
48 }
49
50 /*
51 * This routine will put a word on the process kernel stack.
52 */
53 static inline int
54 put_stack_long(struct task_struct *task, int offset, unsigned long data)
55 {
56 unsigned long *stack;
57
58 stack = (unsigned long *)task_pt_regs(task);
59 stack[offset] = data;
60
61 return 0;
62 }
63
64 static int reg_offset[] = {
65 PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7,
66 PT_R8, PT_R9, PT_R10, PT_R11, PT_R12, PT_FP, PT_LR, PT_SPU,
67 };
68
69 /*
70 * Read the word at offset "off" into the "struct user". We
71 * actually access the pt_regs stored on the kernel stack.
72 */
73 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
74 unsigned long __user *data)
75 {
76 unsigned long tmp;
77 #ifndef NO_FPU
78 struct user * dummy = NULL;
79 #endif
80
81 if ((off & 3) || off > sizeof(struct user) - 3)
82 return -EIO;
83
84 off >>= 2;
85 switch (off) {
86 case PT_EVB:
87 __asm__ __volatile__ (
88 "mvfc %0, cr5 \n\t"
89 : "=r" (tmp)
90 );
91 break;
92 case PT_CBR: {
93 unsigned long psw;
94 psw = get_stack_long(tsk, PT_PSW);
95 tmp = ((psw >> 8) & 1);
96 }
97 break;
98 case PT_PSW: {
99 unsigned long psw, bbpsw;
100 psw = get_stack_long(tsk, PT_PSW);
101 bbpsw = get_stack_long(tsk, PT_BBPSW);
102 tmp = ((psw >> 8) & 0xff) | ((bbpsw & 0xff) << 8);
103 }
104 break;
105 case PT_PC:
106 tmp = get_stack_long(tsk, PT_BPC);
107 break;
108 case PT_BPC:
109 off = PT_BBPC;
110 /* fall through */
111 default:
112 if (off < (sizeof(struct pt_regs) >> 2))
113 tmp = get_stack_long(tsk, off);
114 #ifndef NO_FPU
115 else if (off >= (long)(&dummy->fpu >> 2) &&
116 off < (long)(&dummy->u_fpvalid >> 2)) {
117 if (!tsk_used_math(tsk)) {
118 if (off == (long)(&dummy->fpu.fpscr >> 2))
119 tmp = FPSCR_INIT;
120 else
121 tmp = 0;
122 } else
123 tmp = ((long *)(&tsk->thread.fpu >> 2))
124 [off - (long)&dummy->fpu];
125 } else if (off == (long)(&dummy->u_fpvalid >> 2))
126 tmp = !!tsk_used_math(tsk);
127 #endif /* not NO_FPU */
128 else
129 tmp = 0;
130 }
131
132 return put_user(tmp, data);
133 }
134
135 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
136 unsigned long data)
137 {
138 int ret = -EIO;
139 #ifndef NO_FPU
140 struct user * dummy = NULL;
141 #endif
142
143 if ((off & 3) || off > sizeof(struct user) - 3)
144 return -EIO;
145
146 off >>= 2;
147 switch (off) {
148 case PT_EVB:
149 case PT_BPC:
150 case PT_SPI:
151 /* We don't allow to modify evb. */
152 ret = 0;
153 break;
154 case PT_PSW:
155 case PT_CBR: {
156 /* We allow to modify only cbr in psw */
157 unsigned long psw;
158 psw = get_stack_long(tsk, PT_PSW);
159 psw = (psw & ~0x100) | ((data & 1) << 8);
160 ret = put_stack_long(tsk, PT_PSW, psw);
161 }
162 break;
163 case PT_PC:
164 off = PT_BPC;
165 data &= ~1;
166 /* fall through */
167 default:
168 if (off < (sizeof(struct pt_regs) >> 2))
169 ret = put_stack_long(tsk, off, data);
170 #ifndef NO_FPU
171 else if (off >= (long)(&dummy->fpu >> 2) &&
172 off < (long)(&dummy->u_fpvalid >> 2)) {
173 set_stopped_child_used_math(tsk);
174 ((long *)&tsk->thread.fpu)
175 [off - (long)&dummy->fpu] = data;
176 ret = 0;
177 } else if (off == (long)(&dummy->u_fpvalid >> 2)) {
178 conditional_stopped_child_used_math(data, tsk);
179 ret = 0;
180 }
181 #endif /* not NO_FPU */
182 break;
183 }
184
185 return ret;
186 }
187
188 /*
189 * Get all user integer registers.
190 */
191 static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
192 {
193 struct pt_regs *regs = task_pt_regs(tsk);
194
195 return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
196 }
197
198 /*
199 * Set all user integer registers.
200 */
201 static int ptrace_setregs(struct task_struct *tsk, void __user *uregs)
202 {
203 struct pt_regs newregs;
204 int ret;
205
206 ret = -EFAULT;
207 if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
208 struct pt_regs *regs = task_pt_regs(tsk);
209 *regs = newregs;
210 ret = 0;
211 }
212
213 return ret;
214 }
215
216
217 static inline int
218 check_condition_bit(struct task_struct *child)
219 {
220 return (int)((get_stack_long(child, PT_PSW) >> 8) & 1);
221 }
222
223 static int
224 check_condition_src(unsigned long op, unsigned long regno1,
225 unsigned long regno2, struct task_struct *child)
226 {
227 unsigned long reg1, reg2;
228
229 reg2 = get_stack_long(child, reg_offset[regno2]);
230
231 switch (op) {
232 case 0x0: /* BEQ */
233 reg1 = get_stack_long(child, reg_offset[regno1]);
234 return reg1 == reg2;
235 case 0x1: /* BNE */
236 reg1 = get_stack_long(child, reg_offset[regno1]);
237 return reg1 != reg2;
238 case 0x8: /* BEQZ */
239 return reg2 == 0;
240 case 0x9: /* BNEZ */
241 return reg2 != 0;
242 case 0xa: /* BLTZ */
243 return (int)reg2 < 0;
244 case 0xb: /* BGEZ */
245 return (int)reg2 >= 0;
246 case 0xc: /* BLEZ */
247 return (int)reg2 <= 0;
248 case 0xd: /* BGTZ */
249 return (int)reg2 > 0;
250 default:
251 /* never reached */
252 return 0;
253 }
254 }
255
256 static void
257 compute_next_pc_for_16bit_insn(unsigned long insn, unsigned long pc,
258 unsigned long *next_pc,
259 struct task_struct *child)
260 {
261 unsigned long op, op2, op3;
262 unsigned long disp;
263 unsigned long regno;
264 int parallel = 0;
265
266 if (insn & 0x00008000)
267 parallel = 1;
268 if (pc & 3)
269 insn &= 0x7fff; /* right slot */
270 else
271 insn >>= 16; /* left slot */
272
273 op = (insn >> 12) & 0xf;
274 op2 = (insn >> 8) & 0xf;
275 op3 = (insn >> 4) & 0xf;
276
277 if (op == 0x7) {
278 switch (op2) {
279 case 0xd: /* BNC */
280 case 0x9: /* BNCL */
281 if (!check_condition_bit(child)) {
282 disp = (long)(insn << 24) >> 22;
283 *next_pc = (pc & ~0x3) + disp;
284 return;
285 }
286 break;
287 case 0x8: /* BCL */
288 case 0xc: /* BC */
289 if (check_condition_bit(child)) {
290 disp = (long)(insn << 24) >> 22;
291 *next_pc = (pc & ~0x3) + disp;
292 return;
293 }
294 break;
295 case 0xe: /* BL */
296 case 0xf: /* BRA */
297 disp = (long)(insn << 24) >> 22;
298 *next_pc = (pc & ~0x3) + disp;
299 return;
300 break;
301 }
302 } else if (op == 0x1) {
303 switch (op2) {
304 case 0x0:
305 if (op3 == 0xf) { /* TRAP */
306 #if 1
307 /* pass through */
308 #else
309 /* kernel space is not allowed as next_pc */
310 unsigned long evb;
311 unsigned long trapno;
312 trapno = insn & 0xf;
313 __asm__ __volatile__ (
314 "mvfc %0, cr5\n"
315 :"=r"(evb)
316 :
317 );
318 *next_pc = evb + (trapno << 2);
319 return;
320 #endif
321 } else if (op3 == 0xd) { /* RTE */
322 *next_pc = get_stack_long(child, PT_BPC);
323 return;
324 }
325 break;
326 case 0xc: /* JC */
327 if (op3 == 0xc && check_condition_bit(child)) {
328 regno = insn & 0xf;
329 *next_pc = get_stack_long(child,
330 reg_offset[regno]);
331 return;
332 }
333 break;
334 case 0xd: /* JNC */
335 if (op3 == 0xc && !check_condition_bit(child)) {
336 regno = insn & 0xf;
337 *next_pc = get_stack_long(child,
338 reg_offset[regno]);
339 return;
340 }
341 break;
342 case 0xe: /* JL */
343 case 0xf: /* JMP */
344 if (op3 == 0xc) { /* JMP */
345 regno = insn & 0xf;
346 *next_pc = get_stack_long(child,
347 reg_offset[regno]);
348 return;
349 }
350 break;
351 }
352 }
353 if (parallel)
354 *next_pc = pc + 4;
355 else
356 *next_pc = pc + 2;
357 }
358
359 static void
360 compute_next_pc_for_32bit_insn(unsigned long insn, unsigned long pc,
361 unsigned long *next_pc,
362 struct task_struct *child)
363 {
364 unsigned long op;
365 unsigned long op2;
366 unsigned long disp;
367 unsigned long regno1, regno2;
368
369 op = (insn >> 28) & 0xf;
370 if (op == 0xf) { /* branch 24-bit relative */
371 op2 = (insn >> 24) & 0xf;
372 switch (op2) {
373 case 0xd: /* BNC */
374 case 0x9: /* BNCL */
375 if (!check_condition_bit(child)) {
376 disp = (long)(insn << 8) >> 6;
377 *next_pc = (pc & ~0x3) + disp;
378 return;
379 }
380 break;
381 case 0x8: /* BCL */
382 case 0xc: /* BC */
383 if (check_condition_bit(child)) {
384 disp = (long)(insn << 8) >> 6;
385 *next_pc = (pc & ~0x3) + disp;
386 return;
387 }
388 break;
389 case 0xe: /* BL */
390 case 0xf: /* BRA */
391 disp = (long)(insn << 8) >> 6;
392 *next_pc = (pc & ~0x3) + disp;
393 return;
394 }
395 } else if (op == 0xb) { /* branch 16-bit relative */
396 op2 = (insn >> 20) & 0xf;
397 switch (op2) {
398 case 0x0: /* BEQ */
399 case 0x1: /* BNE */
400 case 0x8: /* BEQZ */
401 case 0x9: /* BNEZ */
402 case 0xa: /* BLTZ */
403 case 0xb: /* BGEZ */
404 case 0xc: /* BLEZ */
405 case 0xd: /* BGTZ */
406 regno1 = ((insn >> 24) & 0xf);
407 regno2 = ((insn >> 16) & 0xf);
408 if (check_condition_src(op2, regno1, regno2, child)) {
409 disp = (long)(insn << 16) >> 14;
410 *next_pc = (pc & ~0x3) + disp;
411 return;
412 }
413 break;
414 }
415 }
416 *next_pc = pc + 4;
417 }
418
419 static inline void
420 compute_next_pc(unsigned long insn, unsigned long pc,
421 unsigned long *next_pc, struct task_struct *child)
422 {
423 if (insn & 0x80000000)
424 compute_next_pc_for_32bit_insn(insn, pc, next_pc, child);
425 else
426 compute_next_pc_for_16bit_insn(insn, pc, next_pc, child);
427 }
428
429 static int
430 register_debug_trap(struct task_struct *child, unsigned long next_pc,
431 unsigned long next_insn, unsigned long *code)
432 {
433 struct debug_trap *p = &child->thread.debug_trap;
434 unsigned long addr = next_pc & ~3;
435
436 if (p->nr_trap == MAX_TRAPS) {
437 printk("kernel BUG at %s %d: p->nr_trap = %d\n",
438 __FILE__, __LINE__, p->nr_trap);
439 return -1;
440 }
441 p->addr[p->nr_trap] = addr;
442 p->insn[p->nr_trap] = next_insn;
443 p->nr_trap++;
444 if (next_pc & 3) {
445 *code = (next_insn & 0xffff0000) | 0x10f1;
446 /* xxx --> TRAP1 */
447 } else {
448 if ((next_insn & 0x80000000) || (next_insn & 0x8000)) {
449 *code = 0x10f17000;
450 /* TRAP1 --> NOP */
451 } else {
452 *code = (next_insn & 0xffff) | 0x10f10000;
453 /* TRAP1 --> xxx */
454 }
455 }
456 return 0;
457 }
458
459 static int
460 unregister_debug_trap(struct task_struct *child, unsigned long addr,
461 unsigned long *code)
462 {
463 struct debug_trap *p = &child->thread.debug_trap;
464 int i;
465
466 /* Search debug trap entry. */
467 for (i = 0; i < p->nr_trap; i++) {
468 if (p->addr[i] == addr)
469 break;
470 }
471 if (i >= p->nr_trap) {
472 /* The trap may be requested from debugger.
473 * ptrace should do nothing in this case.
474 */
475 return 0;
476 }
477
478 /* Recover original instruction code. */
479 *code = p->insn[i];
480
481 /* Shift debug trap entries. */
482 while (i < p->nr_trap - 1) {
483 p->insn[i] = p->insn[i + 1];
484 p->addr[i] = p->addr[i + 1];
485 i++;
486 }
487 p->nr_trap--;
488 return 1;
489 }
490
491 static void
492 unregister_all_debug_traps(struct task_struct *child)
493 {
494 struct debug_trap *p = &child->thread.debug_trap;
495 int i;
496
497 for (i = 0; i < p->nr_trap; i++)
498 access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]),
499 FOLL_FORCE | FOLL_WRITE);
500 p->nr_trap = 0;
501 }
502
503 static inline void
504 invalidate_cache(void)
505 {
506 #if defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP)
507
508 _flush_cache_copyback_all();
509
510 #else /* ! CONFIG_CHIP_M32700 */
511
512 /* Invalidate cache */
513 __asm__ __volatile__ (
514 "ldi r0, #-1 \n\t"
515 "ldi r1, #0 \n\t"
516 "stb r1, @r0 ; cache off \n\t"
517 "; \n\t"
518 "ldi r0, #-2 \n\t"
519 "ldi r1, #1 \n\t"
520 "stb r1, @r0 ; cache invalidate \n\t"
521 ".fillinsn \n"
522 "0: \n\t"
523 "ldb r1, @r0 ; invalidate check \n\t"
524 "bnez r1, 0b \n\t"
525 "; \n\t"
526 "ldi r0, #-1 \n\t"
527 "ldi r1, #1 \n\t"
528 "stb r1, @r0 ; cache on \n\t"
529 : : : "r0", "r1", "memory"
530 );
531 /* FIXME: copying-back d-cache and invalidating i-cache are needed.
532 */
533 #endif /* CONFIG_CHIP_M32700 */
534 }
535
536 /* Embed a debug trap (TRAP1) code */
537 static int
538 embed_debug_trap(struct task_struct *child, unsigned long next_pc)
539 {
540 unsigned long next_insn, code;
541 unsigned long addr = next_pc & ~3;
542
543 if (access_process_vm(child, addr, &next_insn, sizeof(next_insn),
544 FOLL_FORCE)
545 != sizeof(next_insn)) {
546 return -1; /* error */
547 }
548
549 /* Set a trap code. */
550 if (register_debug_trap(child, next_pc, next_insn, &code)) {
551 return -1; /* error */
552 }
553 if (access_process_vm(child, addr, &code, sizeof(code),
554 FOLL_FORCE | FOLL_WRITE)
555 != sizeof(code)) {
556 return -1; /* error */
557 }
558 return 0; /* success */
559 }
560
561 void
562 withdraw_debug_trap(struct pt_regs *regs)
563 {
564 unsigned long addr;
565 unsigned long code;
566
567 addr = (regs->bpc - 2) & ~3;
568 regs->bpc -= 2;
569 if (unregister_debug_trap(current, addr, &code)) {
570 access_process_vm(current, addr, &code, sizeof(code),
571 FOLL_FORCE | FOLL_WRITE);
572 invalidate_cache();
573 }
574 }
575
576 void
577 init_debug_traps(struct task_struct *child)
578 {
579 struct debug_trap *p = &child->thread.debug_trap;
580 int i;
581 p->nr_trap = 0;
582 for (i = 0; i < MAX_TRAPS; i++) {
583 p->addr[i] = 0;
584 p->insn[i] = 0;
585 }
586 }
587
588 void user_enable_single_step(struct task_struct *child)
589 {
590 unsigned long next_pc;
591 unsigned long pc, insn;
592
593 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
594
595 /* Compute next pc. */
596 pc = get_stack_long(child, PT_BPC);
597
598 if (access_process_vm(child, pc&~3, &insn, sizeof(insn),
599 FOLL_FORCE)
600 != sizeof(insn))
601 return;
602
603 compute_next_pc(insn, pc, &next_pc, child);
604 if (next_pc & 0x80000000)
605 return;
606
607 if (embed_debug_trap(child, next_pc))
608 return;
609
610 invalidate_cache();
611 }
612
613 void user_disable_single_step(struct task_struct *child)
614 {
615 unregister_all_debug_traps(child);
616 invalidate_cache();
617 }
618
619 /*
620 * Called by kernel/ptrace.c when detaching..
621 *
622 * Make sure single step bits etc are not set.
623 */
624 void ptrace_disable(struct task_struct *child)
625 {
626 /* nothing to do.. */
627 }
628
629 long
630 arch_ptrace(struct task_struct *child, long request,
631 unsigned long addr, unsigned long data)
632 {
633 int ret;
634 unsigned long __user *datap = (unsigned long __user *) data;
635
636 switch (request) {
637 /*
638 * read word at location "addr" in the child process.
639 */
640 case PTRACE_PEEKTEXT:
641 case PTRACE_PEEKDATA:
642 ret = generic_ptrace_peekdata(child, addr, data);
643 break;
644
645 /*
646 * read the word at location addr in the USER area.
647 */
648 case PTRACE_PEEKUSR:
649 ret = ptrace_read_user(child, addr, datap);
650 break;
651
652 /*
653 * write the word at location addr.
654 */
655 case PTRACE_POKETEXT:
656 case PTRACE_POKEDATA:
657 ret = generic_ptrace_pokedata(child, addr, data);
658 if (ret == 0 && request == PTRACE_POKETEXT)
659 invalidate_cache();
660 break;
661
662 /*
663 * write the word at location addr in the USER area.
664 */
665 case PTRACE_POKEUSR:
666 ret = ptrace_write_user(child, addr, data);
667 break;
668
669 case PTRACE_GETREGS:
670 ret = ptrace_getregs(child, datap);
671 break;
672
673 case PTRACE_SETREGS:
674 ret = ptrace_setregs(child, datap);
675 break;
676
677 default:
678 ret = ptrace_request(child, request, addr, data);
679 break;
680 }
681
682 return ret;
683 }
684
685 /* notification of system call entry/exit
686 * - triggered by current->work.syscall_trace
687 */
688 void do_syscall_trace(void)
689 {
690 if (!test_thread_flag(TIF_SYSCALL_TRACE))
691 return;
692 if (!(current->ptrace & PT_PTRACED))
693 return;
694 /* the 0x80 provides a way for the tracing parent to distinguish
695 between a syscall stop and SIGTRAP delivery */
696 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
697 ? 0x80 : 0));
698
699 /*
700 * this isn't the same as continuing with a signal, but it will do
701 * for normal use. strace only continues with a signal if the
702 * stopping signal is not SIGTRAP. -brl
703 */
704 if (current->exit_code) {
705 send_sig(current->exit_code, current, 1);
706 current->exit_code = 0;
707 }
708 }
Linux with added FPC-III support