LXR linux/arch/sh/kernel/ptrace

   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 */
  58static 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
  67static inline unsigned long
  68get_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 */
  98static 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
 109static inline int
 110put_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
 130void 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
 139void 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
 148static 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
 181static 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
 216int 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
 231static 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
 248static 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
 255const 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 */
 337enum sh_regset {
 338        REGSET_GENERAL,
 339#ifdef CONFIG_SH_FPU
 340        REGSET_FPU,
 341#endif
 342};
 343
 344static 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
 374static 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
 381const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 382{
 383        return &user_sh64_native_view;
 384}
 385
 386long 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
 486asmlinkage 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
 507static 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
 521asmlinkage 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
 546asmlinkage 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 */
 561asmlinkage 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 */
 574BUILD_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 */
 590void ptrace_disable(struct task_struct *child)
 591{
 592        user_disable_single_step(child);
 593}
 594