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