arch/sh/kernel/ptrace_64.c

   1 /*
   2  * arch/sh/kernel/ptrace_64.c
   3  *
   4  * Copyright (C) 2000, 2001  Paolo Alberelli
   5  * Copyright (C) 2003 - 2008  Paul Mundt
   6  *
   7  * Started from SH3/4 version:
   8  *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   9  *
  10  *   Original x86 implementation:
  11  *      By Ross Biro 1/23/92
  12  *      edited by Linus Torvalds
  13  *
  14  * This file is subject to the terms and conditions of the GNU General Public
  15  * License.  See the file "COPYING" in the main directory of this archive
  16  * for more details.
  17  */
  18 #include <linux/kernel.h>
  19 #include <linux/rwsem.h>
  20 #include <linux/sched.h>
  21 #include <linux/mm.h>
  22 #include <linux/smp.h>
  23 #include <linux/bitops.h>
  24 #include <linux/errno.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/user.h>
  27 #include <linux/signal.h>
  28 #include <linux/syscalls.h>
  29 #include <linux/audit.h>
  30 #include <linux/seccomp.h>
  31 #include <linux/tracehook.h>
  32 #include <linux/elf.h>
  33 #include <linux/regset.h>
  34 #include <asm/io.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/processor.h>
  38 #include <asm/mmu_context.h>
  39 #include <asm/syscalls.h>
  40 #include <asm/fpu.h>
  41 #include <asm/traps.h>
  42
  43 #define CREATE_TRACE_POINTS
  44 #include <trace/events/syscalls.h>
  45
  46 /* This mask defines the bits of the SR which the user is not allowed to
  47    change, which are everything except S, Q, M, PR, SZ, FR. */
  48 #define SR_MASK      (0xffff8cfd)
  49
  50 /*
  51  * does not yet catch signals sent when the child dies.
  52  * in exit.c or in signal.c.
  53  */
  54
  55 /*
  56  * This routine will get a word from the user area in the process kernel stack.
  57  */
  58 static inline int get_stack_long(struct task_struct *task, int offset)
  59 {
  60         unsigned char *stack;
  61
  62         stack = (unsigned char *)(task->thread.uregs);
  63         stack += offset;
  64         return (*((int *)stack));
  65 }
  66
  67 static inline unsigned long
  68 get_fpu_long(struct task_struct *task, unsigned long addr)
  69 {
  70         unsigned long tmp;
  71         struct pt_regs *regs;
  72         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
  73
  74         if (!tsk_used_math(task)) {
  75                 if (addr == offsetof(struct user_fpu_struct, fpscr)) {
  76                         tmp = FPSCR_INIT;
  77                 } else {
  78                         tmp = 0xffffffffUL; /* matches initial value in fpu.c */
  79                 }
  80                 return tmp;
  81         }
  82
  83         if (last_task_used_math == task) {
  84                 enable_fpu();
  85                 save_fpu(task);
  86                 disable_fpu();
  87                 last_task_used_math = 0;
  88                 regs->sr |= SR_FD;
  89         }
  90
  91         tmp = ((long *)task->thread.xstate)[addr / sizeof(unsigned long)];
  92         return tmp;
  93 }
  94
  95 /*
  96  * This routine will put a word into the user area in the process kernel stack.
  97  */
  98 static inline int put_stack_long(struct task_struct *task, int offset,
  99                                  unsigned long data)
 100 {
 101         unsigned char *stack;
 102
 103         stack = (unsigned char *)(task->thread.uregs);
 104         stack += offset;
 105         *(unsigned long *) stack = data;
 106         return 0;
 107 }
 108
 109 static inline int
 110 put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
 111 {
 112         struct pt_regs *regs;
 113
 114         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
 115
 116         if (!tsk_used_math(task)) {
 117                 init_fpu(task);
 118         } else if (last_task_used_math == task) {
 119                 enable_fpu();
 120                 save_fpu(task);
 121                 disable_fpu();
 122                 last_task_used_math = 0;
 123                 regs->sr |= SR_FD;
 124         }
 125
 126         ((long *)task->thread.xstate)[addr / sizeof(unsigned long)] = data;
 127         return 0;
 128 }
 129
 130 void user_enable_single_step(struct task_struct *child)
 131 {
 132         struct pt_regs *regs = child->thread.uregs;
 133
 134         regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */
 135
 136         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 137 }
 138
 139 void user_disable_single_step(struct task_struct *child)
 140 {
 141         struct pt_regs *regs = child->thread.uregs;
 142
 143         regs->sr &= ~SR_SSTEP;
 144
 145         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 146 }
 147
 148 static int genregs_get(struct task_struct *target,
 149                        const struct user_regset *regset,
 150                        unsigned int pos, unsigned int count,
 151                        void *kbuf, void __user *ubuf)
 152 {
 153         const struct pt_regs *regs = task_pt_regs(target);
 154         int ret;
 155
 156         /* PC, SR, SYSCALL */
 157         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 158                                   &regs->pc,
 159                                   0, 3 * sizeof(unsigned long long));
 160
 161         /* R1 -> R63 */
 162         if (!ret)
 163                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 164                                           regs->regs,
 165                                           offsetof(struct pt_regs, regs[0]),
 166                                           63 * sizeof(unsigned long long));
 167         /* TR0 -> TR7 */
 168         if (!ret)
 169                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 170                                           regs->tregs,
 171                                           offsetof(struct pt_regs, tregs[0]),
 172                                           8 * sizeof(unsigned long long));
 173
 174         if (!ret)
 175                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 176                                                sizeof(struct pt_regs), -1);
 177
 178         return ret;
 179 }
 180
 181 static int genregs_set(struct task_struct *target,
 182                        const struct user_regset *regset,
 183                        unsigned int pos, unsigned int count,
 184                        const void *kbuf, const void __user *ubuf)
 185 {
 186         struct pt_regs *regs = task_pt_regs(target);
 187         int ret;
 188
 189         /* PC, SR, SYSCALL */
 190         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 191                                  &regs->pc,
 192                                  0, 3 * sizeof(unsigned long long));
 193
 194         /* R1 -> R63 */
 195         if (!ret && count > 0)
 196                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 197                                          regs->regs,
 198                                          offsetof(struct pt_regs, regs[0]),
 199                                          63 * sizeof(unsigned long long));
 200
 201         /* TR0 -> TR7 */
 202         if (!ret && count > 0)
 203                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 204                                          regs->tregs,
 205                                          offsetof(struct pt_regs, tregs[0]),
 206                                          8 * sizeof(unsigned long long));
 207
 208         if (!ret)
 209                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 210                                                 sizeof(struct pt_regs), -1);
 211
 212         return ret;
 213 }
 214
 215 #ifdef CONFIG_SH_FPU
 216 int fpregs_get(struct task_struct *target,
 217                const struct user_regset *regset,
 218                unsigned int pos, unsigned int count,
 219                void *kbuf, void __user *ubuf)
 220 {
 221         int ret;
 222
 223         ret = init_fpu(target);
 224         if (ret)
 225                 return ret;
 226
 227         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 228                                    &target->thread.xstate->hardfpu, 0, -1);
 229 }
 230
 231 static int fpregs_set(struct task_struct *target,
 232                        const struct user_regset *regset,
 233                        unsigned int pos, unsigned int count,
 234                        const void *kbuf, const void __user *ubuf)
 235 {
 236         int ret;
 237
 238         ret = init_fpu(target);
 239         if (ret)
 240                 return ret;
 241
 242         set_stopped_child_used_math(target);
 243
 244         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 245                                   &target->thread.xstate->hardfpu, 0, -1);
 246 }
 247
 248 static int fpregs_active(struct task_struct *target,
 249                          const struct user_regset *regset)
 250 {
 251         return tsk_used_math(target) ? regset->n : 0;
 252 }
 253 #endif
 254
 255 const struct pt_regs_offset regoffset_table[] = {
 256         REG_OFFSET_NAME(pc),
 257         REG_OFFSET_NAME(sr),
 258         REG_OFFSET_NAME(syscall_nr),
 259         REGS_OFFSET_NAME(0),
 260         REGS_OFFSET_NAME(1),
 261         REGS_OFFSET_NAME(2),
 262         REGS_OFFSET_NAME(3),
 263         REGS_OFFSET_NAME(4),
 264         REGS_OFFSET_NAME(5),
 265         REGS_OFFSET_NAME(6),
 266         REGS_OFFSET_NAME(7),
 267         REGS_OFFSET_NAME(8),
 268         REGS_OFFSET_NAME(9),
 269         REGS_OFFSET_NAME(10),
 270         REGS_OFFSET_NAME(11),
 271         REGS_OFFSET_NAME(12),
 272         REGS_OFFSET_NAME(13),
 273         REGS_OFFSET_NAME(14),
 274         REGS_OFFSET_NAME(15),
 275         REGS_OFFSET_NAME(16),
 276         REGS_OFFSET_NAME(17),
 277         REGS_OFFSET_NAME(18),
 278         REGS_OFFSET_NAME(19),
 279         REGS_OFFSET_NAME(20),
 280         REGS_OFFSET_NAME(21),
 281         REGS_OFFSET_NAME(22),
 282         REGS_OFFSET_NAME(23),
 283         REGS_OFFSET_NAME(24),
 284         REGS_OFFSET_NAME(25),
 285         REGS_OFFSET_NAME(26),
 286         REGS_OFFSET_NAME(27),
 287         REGS_OFFSET_NAME(28),
 288         REGS_OFFSET_NAME(29),
 289         REGS_OFFSET_NAME(30),
 290         REGS_OFFSET_NAME(31),
 291         REGS_OFFSET_NAME(32),
 292         REGS_OFFSET_NAME(33),
 293         REGS_OFFSET_NAME(34),
 294         REGS_OFFSET_NAME(35),
 295         REGS_OFFSET_NAME(36),
 296         REGS_OFFSET_NAME(37),
 297         REGS_OFFSET_NAME(38),
 298         REGS_OFFSET_NAME(39),
 299         REGS_OFFSET_NAME(40),
 300         REGS_OFFSET_NAME(41),
 301         REGS_OFFSET_NAME(42),
 302         REGS_OFFSET_NAME(43),
 303         REGS_OFFSET_NAME(44),
 304         REGS_OFFSET_NAME(45),
 305         REGS_OFFSET_NAME(46),
 306         REGS_OFFSET_NAME(47),
 307         REGS_OFFSET_NAME(48),
 308         REGS_OFFSET_NAME(49),
 309         REGS_OFFSET_NAME(50),
 310         REGS_OFFSET_NAME(51),
 311         REGS_OFFSET_NAME(52),
 312         REGS_OFFSET_NAME(53),
 313         REGS_OFFSET_NAME(54),
 314         REGS_OFFSET_NAME(55),
 315         REGS_OFFSET_NAME(56),
 316         REGS_OFFSET_NAME(57),
 317         REGS_OFFSET_NAME(58),
 318         REGS_OFFSET_NAME(59),
 319         REGS_OFFSET_NAME(60),
 320         REGS_OFFSET_NAME(61),
 321         REGS_OFFSET_NAME(62),
 322         REGS_OFFSET_NAME(63),
 323         TREGS_OFFSET_NAME(0),
 324         TREGS_OFFSET_NAME(1),
 325         TREGS_OFFSET_NAME(2),
 326         TREGS_OFFSET_NAME(3),
 327         TREGS_OFFSET_NAME(4),
 328         TREGS_OFFSET_NAME(5),
 329         TREGS_OFFSET_NAME(6),
 330         TREGS_OFFSET_NAME(7),
 331         REG_OFFSET_END,
 332 };
 333
 334 /*
 335  * These are our native regset flavours.
 336  */
 337 enum sh_regset {
 338         REGSET_GENERAL,
 339 #ifdef CONFIG_SH_FPU
 340         REGSET_FPU,
 341 #endif
 342 };
 343
 344 static const struct user_regset sh_regsets[] = {
 345         /*
 346          * Format is:
 347          *      PC, SR, SYSCALL,
 348          *      R1 --> R63,
 349          *      TR0 --> TR7,
 350          */
 351         [REGSET_GENERAL] = {
 352                 .core_note_type = NT_PRSTATUS,
 353                 .n              = ELF_NGREG,
 354                 .size           = sizeof(long long),
 355                 .align          = sizeof(long long),
 356                 .get            = genregs_get,
 357                 .set            = genregs_set,
 358         },
 359
 360 #ifdef CONFIG_SH_FPU
 361         [REGSET_FPU] = {
 362                 .core_note_type = NT_PRFPREG,
 363                 .n              = sizeof(struct user_fpu_struct) /
 364                                   sizeof(long long),
 365                 .size           = sizeof(long long),
 366                 .align          = sizeof(long long),
 367                 .get            = fpregs_get,
 368                 .set            = fpregs_set,
 369                 .active         = fpregs_active,
 370         },
 371 #endif
 372 };
 373
 374 static const struct user_regset_view user_sh64_native_view = {
 375         .name           = "sh64",
 376         .e_machine      = EM_SH,
 377         .regsets        = sh_regsets,
 378         .n              = ARRAY_SIZE(sh_regsets),
 379 };
 380
 381 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 382 {
 383         return &user_sh64_native_view;
 384 }
 385
 386 long arch_ptrace(struct task_struct *child, long request,
 387                  unsigned long addr, unsigned long data)
 388 {
 389         int ret;
 390         unsigned long __user *datap = (unsigned long __user *) data;
 391
 392         switch (request) {
 393         /* read the word at location addr in the USER area. */
 394         case PTRACE_PEEKUSR: {
 395                 unsigned long tmp;
 396
 397                 ret = -EIO;
 398                 if ((addr & 3) || addr < 0)
 399                         break;
 400
 401                 if (addr < sizeof(struct pt_regs))
 402                         tmp = get_stack_long(child, addr);
 403                 else if ((addr >= offsetof(struct user, fpu)) &&
 404                          (addr <  offsetof(struct user, u_fpvalid))) {
 405                         unsigned long index;
 406                         ret = init_fpu(child);
 407                         if (ret)
 408                                 break;
 409                         index = addr - offsetof(struct user, fpu);
 410                         tmp = get_fpu_long(child, index);
 411                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 412                         tmp = !!tsk_used_math(child);
 413                 } else {
 414                         break;
 415                 }
 416                 ret = put_user(tmp, datap);
 417                 break;
 418         }
 419
 420         case PTRACE_POKEUSR:
 421                 /* write the word at location addr in the USER area. We must
 422                    disallow any changes to certain SR bits or u_fpvalid, since
 423                    this could crash the kernel or result in a security
 424                    loophole. */
 425                 ret = -EIO;
 426                 if ((addr & 3) || addr < 0)
 427                         break;
 428
 429                 if (addr < sizeof(struct pt_regs)) {
 430                         /* Ignore change of top 32 bits of SR */
 431                         if (addr == offsetof (struct pt_regs, sr)+4)
 432                         {
 433                                 ret = 0;
 434                                 break;
 435                         }
 436                         /* If lower 32 bits of SR, ignore non-user bits */
 437                         if (addr == offsetof (struct pt_regs, sr))
 438                         {
 439                                 long cursr = get_stack_long(child, addr);
 440                                 data &= ~(SR_MASK);
 441                                 data |= (cursr & SR_MASK);
 442                         }
 443                         ret = put_stack_long(child, addr, data);
 444                 }
 445                 else if ((addr >= offsetof(struct user, fpu)) &&
 446                          (addr <  offsetof(struct user, u_fpvalid))) {
 447                         unsigned long index;
 448                         ret = init_fpu(child);
 449                         if (ret)
 450                                 break;
 451                         index = addr - offsetof(struct user, fpu);
 452                         ret = put_fpu_long(child, index, data);
 453                 }
 454                 break;
 455
 456         case PTRACE_GETREGS:
 457                 return copy_regset_to_user(child, &user_sh64_native_view,
 458                                            REGSET_GENERAL,
 459                                            0, sizeof(struct pt_regs),
 460                                            datap);
 461         case PTRACE_SETREGS:
 462                 return copy_regset_from_user(child, &user_sh64_native_view,
 463                                              REGSET_GENERAL,
 464                                              0, sizeof(struct pt_regs),
 465                                              datap);
 466 #ifdef CONFIG_SH_FPU
 467         case PTRACE_GETFPREGS:
 468                 return copy_regset_to_user(child, &user_sh64_native_view,
 469                                            REGSET_FPU,
 470                                            0, sizeof(struct user_fpu_struct),
 471                                            datap);
 472         case PTRACE_SETFPREGS:
 473                 return copy_regset_from_user(child, &user_sh64_native_view,
 474                                              REGSET_FPU,
 475                                              0, sizeof(struct user_fpu_struct),
 476                                              datap);
 477 #endif
 478         default:
 479                 ret = ptrace_request(child, request, addr, data);
 480                 break;
 481         }
 482
 483         return ret;
 484 }
 485
 486 asmlinkage int sh64_ptrace(long request, long pid,
 487                            unsigned long addr, unsigned long data)
 488 {
 489 #define WPC_DBRMODE 0x0d104008
 490         static unsigned long first_call;
 491
 492         if (!test_and_set_bit(0, &first_call)) {
 493                 /* Set WPC.DBRMODE to 0.  This makes all debug events get
 494                  * delivered through RESVEC, i.e. into the handlers in entry.S.
 495                  * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
 496                  * would normally be left set to 1, which makes debug events get
 497                  * delivered through DBRVEC, i.e. into the remote gdb's
 498                  * handlers.  This prevents ptrace getting them, and confuses
 499                  * the remote gdb.) */
 500                 printk("DBRMODE set to 0 to permit native debugging\n");
 501                 poke_real_address_q(WPC_DBRMODE, 0);
 502         }
 503
 504         return sys_ptrace(request, pid, addr, data);
 505 }
 506
 507 static inline int audit_arch(void)
 508 {
 509         int arch = EM_SH;
 510
 511 #ifdef CONFIG_64BIT
 512         arch |= __AUDIT_ARCH_64BIT;
 513 #endif
 514 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 515         arch |= __AUDIT_ARCH_LE;
 516 #endif
 517
 518         return arch;
 519 }
 520
 521 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
 522 {
 523         long long ret = 0;
 524
 525         secure_computing_strict(regs->regs[9]);
 526
 527         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 528             tracehook_report_syscall_entry(regs))
 529                 /*
 530                  * Tracing decided this syscall should not happen.
 531                  * We'll return a bogus call number to get an ENOSYS
 532                  * error, but leave the original number in regs->regs[0].
 533                  */
 534                 ret = -1LL;
 535
 536         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 537                 trace_sys_enter(regs, regs->regs[9]);
 538
 539         audit_syscall_entry(audit_arch(), regs->regs[1],
 540                             regs->regs[2], regs->regs[3],
 541                             regs->regs[4], regs->regs[5]);
 542
 543         return ret ?: regs->regs[9];
 544 }
 545
 546 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 547 {
 548         int step;
 549
 550         audit_syscall_exit(regs);
 551
 552         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 553                 trace_sys_exit(regs, regs->regs[9]);
 554
 555         step = test_thread_flag(TIF_SINGLESTEP);
 556         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 557                 tracehook_report_syscall_exit(regs, step);
 558 }
 559
 560 /* Called with interrupts disabled */
 561 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 562 {
 563         /* This is called after a single step exception (DEBUGSS).
 564            There is no need to change the PC, as it is a post-execution
 565            exception, as entry.S does not do anything to the PC for DEBUGSS.
 566            We need to clear the Single Step setting in SR to avoid
 567            continually stepping. */
 568         local_irq_enable();
 569         regs->sr &= ~SR_SSTEP;
 570         force_sig(SIGTRAP, current);
 571 }
 572
 573 /* Called with interrupts disabled */
 574 BUILD_TRAP_HANDLER(breakpoint)
 575 {
 576         TRAP_HANDLER_DECL;
 577
 578         /* We need to forward step the PC, to counteract the backstep done
 579            in signal.c. */
 580         local_irq_enable();
 581         force_sig(SIGTRAP, current);
 582         regs->pc += 4;
 583 }
 584
 585 /*
 586  * Called by kernel/ptrace.c when detaching..
 587  *
 588  * Make sure single step bits etc are not set.
 589  */
 590 void ptrace_disable(struct task_struct *child)
 591 {
 592         user_disable_single_step(child);
 593 }