arch/sh/kernel/ptrace_64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/sh/kernel/ptrace_64.c
   4  *
   5  * Copyright (C) 2000, 2001  Paolo Alberelli
   6  * Copyright (C) 2003 - 2008  Paul Mundt
   7  *
   8  * Started from SH3/4 version:
   9  *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
  10  *
  11  *   Original x86 implementation:
  12  *      By Ross Biro 1/23/92
  13  *      edited by Linus Torvalds
  14  */
  15 #include <linux/kernel.h>
  16 #include <linux/rwsem.h>
  17 #include <linux/sched.h>
  18 #include <linux/sched/task_stack.h>
  19 #include <linux/mm.h>
  20 #include <linux/smp.h>
  21 #include <linux/bitops.h>
  22 #include <linux/errno.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/user.h>
  25 #include <linux/signal.h>
  26 #include <linux/syscalls.h>
  27 #include <linux/audit.h>
  28 #include <linux/seccomp.h>
  29 #include <linux/tracehook.h>
  30 #include <linux/elf.h>
  31 #include <linux/regset.h>
  32 #include <asm/io.h>
  33 #include <linux/uaccess.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/processor.h>
  36 #include <asm/mmu_context.h>
  37 #include <asm/syscalls.h>
  38 #include <asm/fpu.h>
  39 #include <asm/traps.h>
  40
  41 #define CREATE_TRACE_POINTS
  42 #include <trace/events/syscalls.h>
  43
  44 /* This mask defines the bits of the SR which the user is not allowed to
  45    change, which are everything except S, Q, M, PR, SZ, FR. */
  46 #define SR_MASK      (0xffff8cfd)
  47
  48 /*
  49  * does not yet catch signals sent when the child dies.
  50  * in exit.c or in signal.c.
  51  */
  52
  53 /*
  54  * This routine will get a word from the user area in the process kernel stack.
  55  */
  56 static inline int get_stack_long(struct task_struct *task, int offset)
  57 {
  58         unsigned char *stack;
  59
  60         stack = (unsigned char *)(task->thread.uregs);
  61         stack += offset;
  62         return (*((int *)stack));
  63 }
  64
  65 static inline unsigned long
  66 get_fpu_long(struct task_struct *task, unsigned long addr)
  67 {
  68         unsigned long tmp;
  69         struct pt_regs *regs;
  70         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
  71
  72         if (!tsk_used_math(task)) {
  73                 if (addr == offsetof(struct user_fpu_struct, fpscr)) {
  74                         tmp = FPSCR_INIT;
  75                 } else {
  76                         tmp = 0xffffffffUL; /* matches initial value in fpu.c */
  77                 }
  78                 return tmp;
  79         }
  80
  81         if (last_task_used_math == task) {
  82                 enable_fpu();
  83                 save_fpu(task);
  84                 disable_fpu();
  85                 last_task_used_math = 0;
  86                 regs->sr |= SR_FD;
  87         }
  88
  89         tmp = ((long *)task->thread.xstate)[addr / sizeof(unsigned long)];
  90         return tmp;
  91 }
  92
  93 /*
  94  * This routine will put a word into the user area in the process kernel stack.
  95  */
  96 static inline int put_stack_long(struct task_struct *task, int offset,
  97                                  unsigned long data)
  98 {
  99         unsigned char *stack;
 100
 101         stack = (unsigned char *)(task->thread.uregs);
 102         stack += offset;
 103         *(unsigned long *) stack = data;
 104         return 0;
 105 }
 106
 107 static inline int
 108 put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
 109 {
 110         struct pt_regs *regs;
 111
 112         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
 113
 114         if (!tsk_used_math(task)) {
 115                 init_fpu(task);
 116         } else if (last_task_used_math == task) {
 117                 enable_fpu();
 118                 save_fpu(task);
 119                 disable_fpu();
 120                 last_task_used_math = 0;
 121                 regs->sr |= SR_FD;
 122         }
 123
 124         ((long *)task->thread.xstate)[addr / sizeof(unsigned long)] = data;
 125         return 0;
 126 }
 127
 128 void user_enable_single_step(struct task_struct *child)
 129 {
 130         struct pt_regs *regs = child->thread.uregs;
 131
 132         regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */
 133
 134         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 135 }
 136
 137 void user_disable_single_step(struct task_struct *child)
 138 {
 139         struct pt_regs *regs = child->thread.uregs;
 140
 141         regs->sr &= ~SR_SSTEP;
 142
 143         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 144 }
 145
 146 static int genregs_get(struct task_struct *target,
 147                        const struct user_regset *regset,
 148                        unsigned int pos, unsigned int count,
 149                        void *kbuf, void __user *ubuf)
 150 {
 151         const struct pt_regs *regs = task_pt_regs(target);
 152         int ret;
 153
 154         /* PC, SR, SYSCALL */
 155         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 156                                   &regs->pc,
 157                                   0, 3 * sizeof(unsigned long long));
 158
 159         /* R1 -> R63 */
 160         if (!ret)
 161                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 162                                           regs->regs,
 163                                           offsetof(struct pt_regs, regs[0]),
 164                                           63 * sizeof(unsigned long long));
 165         /* TR0 -> TR7 */
 166         if (!ret)
 167                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 168                                           regs->tregs,
 169                                           offsetof(struct pt_regs, tregs[0]),
 170                                           8 * sizeof(unsigned long long));
 171
 172         if (!ret)
 173                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 174                                                sizeof(struct pt_regs), -1);
 175
 176         return ret;
 177 }
 178
 179 static int genregs_set(struct task_struct *target,
 180                        const struct user_regset *regset,
 181                        unsigned int pos, unsigned int count,
 182                        const void *kbuf, const void __user *ubuf)
 183 {
 184         struct pt_regs *regs = task_pt_regs(target);
 185         int ret;
 186
 187         /* PC, SR, SYSCALL */
 188         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 189                                  &regs->pc,
 190                                  0, 3 * sizeof(unsigned long long));
 191
 192         /* R1 -> R63 */
 193         if (!ret && count > 0)
 194                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 195                                          regs->regs,
 196                                          offsetof(struct pt_regs, regs[0]),
 197                                          63 * sizeof(unsigned long long));
 198
 199         /* TR0 -> TR7 */
 200         if (!ret && count > 0)
 201                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 202                                          regs->tregs,
 203                                          offsetof(struct pt_regs, tregs[0]),
 204                                          8 * sizeof(unsigned long long));
 205
 206         if (!ret)
 207                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 208                                                 sizeof(struct pt_regs), -1);
 209
 210         return ret;
 211 }
 212
 213 #ifdef CONFIG_SH_FPU
 214 int fpregs_get(struct task_struct *target,
 215                const struct user_regset *regset,
 216                unsigned int pos, unsigned int count,
 217                void *kbuf, void __user *ubuf)
 218 {
 219         int ret;
 220
 221         ret = init_fpu(target);
 222         if (ret)
 223                 return ret;
 224
 225         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 226                                    &target->thread.xstate->hardfpu, 0, -1);
 227 }
 228
 229 static int fpregs_set(struct task_struct *target,
 230                        const struct user_regset *regset,
 231                        unsigned int pos, unsigned int count,
 232                        const void *kbuf, const void __user *ubuf)
 233 {
 234         int ret;
 235
 236         ret = init_fpu(target);
 237         if (ret)
 238                 return ret;
 239
 240         set_stopped_child_used_math(target);
 241
 242         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 243                                   &target->thread.xstate->hardfpu, 0, -1);
 244 }
 245
 246 static int fpregs_active(struct task_struct *target,
 247                          const struct user_regset *regset)
 248 {
 249         return tsk_used_math(target) ? regset->n : 0;
 250 }
 251 #endif
 252
 253 const struct pt_regs_offset regoffset_table[] = {
 254         REG_OFFSET_NAME(pc),
 255         REG_OFFSET_NAME(sr),
 256         REG_OFFSET_NAME(syscall_nr),
 257         REGS_OFFSET_NAME(0),
 258         REGS_OFFSET_NAME(1),
 259         REGS_OFFSET_NAME(2),
 260         REGS_OFFSET_NAME(3),
 261         REGS_OFFSET_NAME(4),
 262         REGS_OFFSET_NAME(5),
 263         REGS_OFFSET_NAME(6),
 264         REGS_OFFSET_NAME(7),
 265         REGS_OFFSET_NAME(8),
 266         REGS_OFFSET_NAME(9),
 267         REGS_OFFSET_NAME(10),
 268         REGS_OFFSET_NAME(11),
 269         REGS_OFFSET_NAME(12),
 270         REGS_OFFSET_NAME(13),
 271         REGS_OFFSET_NAME(14),
 272         REGS_OFFSET_NAME(15),
 273         REGS_OFFSET_NAME(16),
 274         REGS_OFFSET_NAME(17),
 275         REGS_OFFSET_NAME(18),
 276         REGS_OFFSET_NAME(19),
 277         REGS_OFFSET_NAME(20),
 278         REGS_OFFSET_NAME(21),
 279         REGS_OFFSET_NAME(22),
 280         REGS_OFFSET_NAME(23),
 281         REGS_OFFSET_NAME(24),
 282         REGS_OFFSET_NAME(25),
 283         REGS_OFFSET_NAME(26),
 284         REGS_OFFSET_NAME(27),
 285         REGS_OFFSET_NAME(28),
 286         REGS_OFFSET_NAME(29),
 287         REGS_OFFSET_NAME(30),
 288         REGS_OFFSET_NAME(31),
 289         REGS_OFFSET_NAME(32),
 290         REGS_OFFSET_NAME(33),
 291         REGS_OFFSET_NAME(34),
 292         REGS_OFFSET_NAME(35),
 293         REGS_OFFSET_NAME(36),
 294         REGS_OFFSET_NAME(37),
 295         REGS_OFFSET_NAME(38),
 296         REGS_OFFSET_NAME(39),
 297         REGS_OFFSET_NAME(40),
 298         REGS_OFFSET_NAME(41),
 299         REGS_OFFSET_NAME(42),
 300         REGS_OFFSET_NAME(43),
 301         REGS_OFFSET_NAME(44),
 302         REGS_OFFSET_NAME(45),
 303         REGS_OFFSET_NAME(46),
 304         REGS_OFFSET_NAME(47),
 305         REGS_OFFSET_NAME(48),
 306         REGS_OFFSET_NAME(49),
 307         REGS_OFFSET_NAME(50),
 308         REGS_OFFSET_NAME(51),
 309         REGS_OFFSET_NAME(52),
 310         REGS_OFFSET_NAME(53),
 311         REGS_OFFSET_NAME(54),
 312         REGS_OFFSET_NAME(55),
 313         REGS_OFFSET_NAME(56),
 314         REGS_OFFSET_NAME(57),
 315         REGS_OFFSET_NAME(58),
 316         REGS_OFFSET_NAME(59),
 317         REGS_OFFSET_NAME(60),
 318         REGS_OFFSET_NAME(61),
 319         REGS_OFFSET_NAME(62),
 320         REGS_OFFSET_NAME(63),
 321         TREGS_OFFSET_NAME(0),
 322         TREGS_OFFSET_NAME(1),
 323         TREGS_OFFSET_NAME(2),
 324         TREGS_OFFSET_NAME(3),
 325         TREGS_OFFSET_NAME(4),
 326         TREGS_OFFSET_NAME(5),
 327         TREGS_OFFSET_NAME(6),
 328         TREGS_OFFSET_NAME(7),
 329         REG_OFFSET_END,
 330 };
 331
 332 /*
 333  * These are our native regset flavours.
 334  */
 335 enum sh_regset {
 336         REGSET_GENERAL,
 337 #ifdef CONFIG_SH_FPU
 338         REGSET_FPU,
 339 #endif
 340 };
 341
 342 static const struct user_regset sh_regsets[] = {
 343         /*
 344          * Format is:
 345          *      PC, SR, SYSCALL,
 346          *      R1 --> R63,
 347          *      TR0 --> TR7,
 348          */
 349         [REGSET_GENERAL] = {
 350                 .core_note_type = NT_PRSTATUS,
 351                 .n              = ELF_NGREG,
 352                 .size           = sizeof(long long),
 353                 .align          = sizeof(long long),
 354                 .get            = genregs_get,
 355                 .set            = genregs_set,
 356         },
 357
 358 #ifdef CONFIG_SH_FPU
 359         [REGSET_FPU] = {
 360                 .core_note_type = NT_PRFPREG,
 361                 .n              = sizeof(struct user_fpu_struct) /
 362                                   sizeof(long long),
 363                 .size           = sizeof(long long),
 364                 .align          = sizeof(long long),
 365                 .get            = fpregs_get,
 366                 .set            = fpregs_set,
 367                 .active         = fpregs_active,
 368         },
 369 #endif
 370 };
 371
 372 static const struct user_regset_view user_sh64_native_view = {
 373         .name           = "sh64",
 374         .e_machine      = EM_SH,
 375         .regsets        = sh_regsets,
 376         .n              = ARRAY_SIZE(sh_regsets),
 377 };
 378
 379 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 380 {
 381         return &user_sh64_native_view;
 382 }
 383
 384 long arch_ptrace(struct task_struct *child, long request,
 385                  unsigned long addr, unsigned long data)
 386 {
 387         int ret;
 388         unsigned long __user *datap = (unsigned long __user *) data;
 389
 390         switch (request) {
 391         /* read the word at location addr in the USER area. */
 392         case PTRACE_PEEKUSR: {
 393                 unsigned long tmp;
 394
 395                 ret = -EIO;
 396                 if ((addr & 3) || addr < 0)
 397                         break;
 398
 399                 if (addr < sizeof(struct pt_regs))
 400                         tmp = get_stack_long(child, addr);
 401                 else if ((addr >= offsetof(struct user, fpu)) &&
 402                          (addr <  offsetof(struct user, u_fpvalid))) {
 403                         unsigned long index;
 404                         ret = init_fpu(child);
 405                         if (ret)
 406                                 break;
 407                         index = addr - offsetof(struct user, fpu);
 408                         tmp = get_fpu_long(child, index);
 409                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 410                         tmp = !!tsk_used_math(child);
 411                 } else {
 412                         break;
 413                 }
 414                 ret = put_user(tmp, datap);
 415                 break;
 416         }
 417
 418         case PTRACE_POKEUSR:
 419                 /* write the word at location addr in the USER area. We must
 420                    disallow any changes to certain SR bits or u_fpvalid, since
 421                    this could crash the kernel or result in a security
 422                    loophole. */
 423                 ret = -EIO;
 424                 if ((addr & 3) || addr < 0)
 425                         break;
 426
 427                 if (addr < sizeof(struct pt_regs)) {
 428                         /* Ignore change of top 32 bits of SR */
 429                         if (addr == offsetof (struct pt_regs, sr)+4)
 430                         {
 431                                 ret = 0;
 432                                 break;
 433                         }
 434                         /* If lower 32 bits of SR, ignore non-user bits */
 435                         if (addr == offsetof (struct pt_regs, sr))
 436                         {
 437                                 long cursr = get_stack_long(child, addr);
 438                                 data &= ~(SR_MASK);
 439                                 data |= (cursr & SR_MASK);
 440                         }
 441                         ret = put_stack_long(child, addr, data);
 442                 }
 443                 else if ((addr >= offsetof(struct user, fpu)) &&
 444                          (addr <  offsetof(struct user, u_fpvalid))) {
 445                         unsigned long index;
 446                         ret = init_fpu(child);
 447                         if (ret)
 448                                 break;
 449                         index = addr - offsetof(struct user, fpu);
 450                         ret = put_fpu_long(child, index, data);
 451                 }
 452                 break;
 453
 454         case PTRACE_GETREGS:
 455                 return copy_regset_to_user(child, &user_sh64_native_view,
 456                                            REGSET_GENERAL,
 457                                            0, sizeof(struct pt_regs),
 458                                            datap);
 459         case PTRACE_SETREGS:
 460                 return copy_regset_from_user(child, &user_sh64_native_view,
 461                                              REGSET_GENERAL,
 462                                              0, sizeof(struct pt_regs),
 463                                              datap);
 464 #ifdef CONFIG_SH_FPU
 465         case PTRACE_GETFPREGS:
 466                 return copy_regset_to_user(child, &user_sh64_native_view,
 467                                            REGSET_FPU,
 468                                            0, sizeof(struct user_fpu_struct),
 469                                            datap);
 470         case PTRACE_SETFPREGS:
 471                 return copy_regset_from_user(child, &user_sh64_native_view,
 472                                              REGSET_FPU,
 473                                              0, sizeof(struct user_fpu_struct),
 474                                              datap);
 475 #endif
 476         default:
 477                 ret = ptrace_request(child, request, addr, data);
 478                 break;
 479         }
 480
 481         return ret;
 482 }
 483
 484 asmlinkage int sh64_ptrace(long request, long pid,
 485                            unsigned long addr, unsigned long data)
 486 {
 487 #define WPC_DBRMODE 0x0d104008
 488         static unsigned long first_call;
 489
 490         if (!test_and_set_bit(0, &first_call)) {
 491                 /* Set WPC.DBRMODE to 0.  This makes all debug events get
 492                  * delivered through RESVEC, i.e. into the handlers in entry.S.
 493                  * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
 494                  * would normally be left set to 1, which makes debug events get
 495                  * delivered through DBRVEC, i.e. into the remote gdb's
 496                  * handlers.  This prevents ptrace getting them, and confuses
 497                  * the remote gdb.) */
 498                 printk("DBRMODE set to 0 to permit native debugging\n");
 499                 poke_real_address_q(WPC_DBRMODE, 0);
 500         }
 501
 502         return sys_ptrace(request, pid, addr, data);
 503 }
 504
 505 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
 506 {
 507         long long ret = 0;
 508
 509         secure_computing_strict(regs->regs[9]);
 510
 511         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 512             tracehook_report_syscall_entry(regs))
 513                 /*
 514                  * Tracing decided this syscall should not happen.
 515                  * We'll return a bogus call number to get an ENOSYS
 516                  * error, but leave the original number in regs->regs[0].
 517                  */
 518                 ret = -1LL;
 519
 520         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 521                 trace_sys_enter(regs, regs->regs[9]);
 522
 523         audit_syscall_entry(regs->regs[1], regs->regs[2], regs->regs[3],
 524                             regs->regs[4], regs->regs[5]);
 525
 526         return ret ?: regs->regs[9];
 527 }
 528
 529 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 530 {
 531         int step;
 532
 533         audit_syscall_exit(regs);
 534
 535         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 536                 trace_sys_exit(regs, regs->regs[9]);
 537
 538         step = test_thread_flag(TIF_SINGLESTEP);
 539         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 540                 tracehook_report_syscall_exit(regs, step);
 541 }
 542
 543 /* Called with interrupts disabled */
 544 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 545 {
 546         /* This is called after a single step exception (DEBUGSS).
 547            There is no need to change the PC, as it is a post-execution
 548            exception, as entry.S does not do anything to the PC for DEBUGSS.
 549            We need to clear the Single Step setting in SR to avoid
 550            continually stepping. */
 551         local_irq_enable();
 552         regs->sr &= ~SR_SSTEP;
 553         force_sig(SIGTRAP);
 554 }
 555
 556 /* Called with interrupts disabled */
 557 BUILD_TRAP_HANDLER(breakpoint)
 558 {
 559         TRAP_HANDLER_DECL;
 560
 561         /* We need to forward step the PC, to counteract the backstep done
 562            in signal.c. */
 563         local_irq_enable();
 564         force_sig(SIGTRAP);
 565         regs->pc += 4;
 566 }
 567
 568 /*
 569  * Called by kernel/ptrace.c when detaching..
 570  *
 571  * Make sure single step bits etc are not set.
 572  */
 573 void ptrace_disable(struct task_struct *child)
 574 {
 575         user_disable_single_step(child);
 576 }