LXR linux/arch/sh/kernel/ptrace

   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 */
  56static 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
  65static inline unsigned long
  66get_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 */
  96static 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
 107static inline int
 108put_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
 128void 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
 137void 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
 146static 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
 179static 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
 214int 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
 229static 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
 246static 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
 253const 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 */
 335enum sh_regset {
 336        REGSET_GENERAL,
 337#ifdef CONFIG_SH_FPU
 338        REGSET_FPU,
 339#endif
 340};
 341
 342static 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
 372static 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
 379const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 380{
 381        return &user_sh64_native_view;
 382}
 383
 384long 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
 484asmlinkage 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
 505asmlinkage 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
 529asmlinkage 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 */
 544asmlinkage 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, current);
 554}
 555
 556/* Called with interrupts disabled */
 557BUILD_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, current);
 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 */
 573void ptrace_disable(struct task_struct *child)
 574{
 575        user_disable_single_step(child);
 576}
 577