arch/m32r/kernel/ptrace.c

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