arch/sh/kernel/ptrace_32.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SuperH process tracing
   4  *
   5  * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   6  * Copyright (C) 2002 - 2009  Paul Mundt
   7  *
   8  * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/sched.h>
  12 #include <linux/sched/task_stack.h>
  13 #include <linux/mm.h>
  14 #include <linux/smp.h>
  15 #include <linux/errno.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/user.h>
  18 #include <linux/security.h>
  19 #include <linux/signal.h>
  20 #include <linux/io.h>
  21 #include <linux/audit.h>
  22 #include <linux/seccomp.h>
  23 #include <linux/tracehook.h>
  24 #include <linux/elf.h>
  25 #include <linux/regset.h>
  26 #include <linux/hw_breakpoint.h>
  27 #include <linux/uaccess.h>
  28 #include <asm/pgtable.h>
  29 #include <asm/processor.h>
  30 #include <asm/mmu_context.h>
  31 #include <asm/syscalls.h>
  32 #include <asm/fpu.h>
  33
  34 #define CREATE_TRACE_POINTS
  35 #include <trace/events/syscalls.h>
  36
  37 /*
  38  * This routine will get a word off of the process kernel stack.
  39  */
  40 static inline int get_stack_long(struct task_struct *task, int offset)
  41 {
  42         unsigned char *stack;
  43
  44         stack = (unsigned char *)task_pt_regs(task);
  45         stack += offset;
  46         return (*((int *)stack));
  47 }
  48
  49 /*
  50  * This routine will put a word on the process kernel stack.
  51  */
  52 static inline int put_stack_long(struct task_struct *task, int offset,
  53                                  unsigned long data)
  54 {
  55         unsigned char *stack;
  56
  57         stack = (unsigned char *)task_pt_regs(task);
  58         stack += offset;
  59         *(unsigned long *) stack = data;
  60         return 0;
  61 }
  62
  63 void ptrace_triggered(struct perf_event *bp,
  64                       struct perf_sample_data *data, struct pt_regs *regs)
  65 {
  66         struct perf_event_attr attr;
  67
  68         /*
  69          * Disable the breakpoint request here since ptrace has defined a
  70          * one-shot behaviour for breakpoint exceptions.
  71          */
  72         attr = bp->attr;
  73         attr.disabled = true;
  74         modify_user_hw_breakpoint(bp, &attr);
  75 }
  76
  77 static int set_single_step(struct task_struct *tsk, unsigned long addr)
  78 {
  79         struct thread_struct *thread = &tsk->thread;
  80         struct perf_event *bp;
  81         struct perf_event_attr attr;
  82
  83         bp = thread->ptrace_bps[0];
  84         if (!bp) {
  85                 ptrace_breakpoint_init(&attr);
  86
  87                 attr.bp_addr = addr;
  88                 attr.bp_len = HW_BREAKPOINT_LEN_2;
  89                 attr.bp_type = HW_BREAKPOINT_R;
  90
  91                 bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
  92                                                  NULL, tsk);
  93                 if (IS_ERR(bp))
  94                         return PTR_ERR(bp);
  95
  96                 thread->ptrace_bps[0] = bp;
  97         } else {
  98                 int err;
  99
 100                 attr = bp->attr;
 101                 attr.bp_addr = addr;
 102                 /* reenable breakpoint */
 103                 attr.disabled = false;
 104                 err = modify_user_hw_breakpoint(bp, &attr);
 105                 if (unlikely(err))
 106                         return err;
 107         }
 108
 109         return 0;
 110 }
 111
 112 void user_enable_single_step(struct task_struct *child)
 113 {
 114         unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));
 115
 116         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 117
 118         set_single_step(child, pc);
 119 }
 120
 121 void user_disable_single_step(struct task_struct *child)
 122 {
 123         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 124 }
 125
 126 /*
 127  * Called by kernel/ptrace.c when detaching..
 128  *
 129  * Make sure single step bits etc are not set.
 130  */
 131 void ptrace_disable(struct task_struct *child)
 132 {
 133         user_disable_single_step(child);
 134 }
 135
 136 static int genregs_get(struct task_struct *target,
 137                        const struct user_regset *regset,
 138                        unsigned int pos, unsigned int count,
 139                        void *kbuf, void __user *ubuf)
 140 {
 141         const struct pt_regs *regs = task_pt_regs(target);
 142         int ret;
 143
 144         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 145                                   regs->regs,
 146                                   0, 16 * sizeof(unsigned long));
 147         if (!ret)
 148                 /* PC, PR, SR, GBR, MACH, MACL, TRA */
 149                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 150                                           &regs->pc,
 151                                           offsetof(struct pt_regs, pc),
 152                                           sizeof(struct pt_regs));
 153         if (!ret)
 154                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 155                                                sizeof(struct pt_regs), -1);
 156
 157         return ret;
 158 }
 159
 160 static int genregs_set(struct task_struct *target,
 161                        const struct user_regset *regset,
 162                        unsigned int pos, unsigned int count,
 163                        const void *kbuf, const void __user *ubuf)
 164 {
 165         struct pt_regs *regs = task_pt_regs(target);
 166         int ret;
 167
 168         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 169                                  regs->regs,
 170                                  0, 16 * sizeof(unsigned long));
 171         if (!ret && count > 0)
 172                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 173                                          &regs->pc,
 174                                          offsetof(struct pt_regs, pc),
 175                                          sizeof(struct pt_regs));
 176         if (!ret)
 177                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 178                                                 sizeof(struct pt_regs), -1);
 179
 180         return ret;
 181 }
 182
 183 #ifdef CONFIG_SH_FPU
 184 int fpregs_get(struct task_struct *target,
 185                const struct user_regset *regset,
 186                unsigned int pos, unsigned int count,
 187                void *kbuf, void __user *ubuf)
 188 {
 189         int ret;
 190
 191         ret = init_fpu(target);
 192         if (ret)
 193                 return ret;
 194
 195         if ((boot_cpu_data.flags & CPU_HAS_FPU))
 196                 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 197                                            &target->thread.xstate->hardfpu, 0, -1);
 198
 199         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 200                                    &target->thread.xstate->softfpu, 0, -1);
 201 }
 202
 203 static int fpregs_set(struct task_struct *target,
 204                        const struct user_regset *regset,
 205                        unsigned int pos, unsigned int count,
 206                        const void *kbuf, const void __user *ubuf)
 207 {
 208         int ret;
 209
 210         ret = init_fpu(target);
 211         if (ret)
 212                 return ret;
 213
 214         set_stopped_child_used_math(target);
 215
 216         if ((boot_cpu_data.flags & CPU_HAS_FPU))
 217                 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 218                                           &target->thread.xstate->hardfpu, 0, -1);
 219
 220         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 221                                   &target->thread.xstate->softfpu, 0, -1);
 222 }
 223
 224 static int fpregs_active(struct task_struct *target,
 225                          const struct user_regset *regset)
 226 {
 227         return tsk_used_math(target) ? regset->n : 0;
 228 }
 229 #endif
 230
 231 #ifdef CONFIG_SH_DSP
 232 static int dspregs_get(struct task_struct *target,
 233                        const struct user_regset *regset,
 234                        unsigned int pos, unsigned int count,
 235                        void *kbuf, void __user *ubuf)
 236 {
 237         const struct pt_dspregs *regs =
 238                 (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
 239         int ret;
 240
 241         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs,
 242                                   0, sizeof(struct pt_dspregs));
 243         if (!ret)
 244                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 245                                                sizeof(struct pt_dspregs), -1);
 246
 247         return ret;
 248 }
 249
 250 static int dspregs_set(struct task_struct *target,
 251                        const struct user_regset *regset,
 252                        unsigned int pos, unsigned int count,
 253                        const void *kbuf, const void __user *ubuf)
 254 {
 255         struct pt_dspregs *regs =
 256                 (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
 257         int ret;
 258
 259         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
 260                                  0, sizeof(struct pt_dspregs));
 261         if (!ret)
 262                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 263                                                 sizeof(struct pt_dspregs), -1);
 264
 265         return ret;
 266 }
 267
 268 static int dspregs_active(struct task_struct *target,
 269                           const struct user_regset *regset)
 270 {
 271         struct pt_regs *regs = task_pt_regs(target);
 272
 273         return regs->sr & SR_DSP ? regset->n : 0;
 274 }
 275 #endif
 276
 277 const struct pt_regs_offset regoffset_table[] = {
 278         REGS_OFFSET_NAME(0),
 279         REGS_OFFSET_NAME(1),
 280         REGS_OFFSET_NAME(2),
 281         REGS_OFFSET_NAME(3),
 282         REGS_OFFSET_NAME(4),
 283         REGS_OFFSET_NAME(5),
 284         REGS_OFFSET_NAME(6),
 285         REGS_OFFSET_NAME(7),
 286         REGS_OFFSET_NAME(8),
 287         REGS_OFFSET_NAME(9),
 288         REGS_OFFSET_NAME(10),
 289         REGS_OFFSET_NAME(11),
 290         REGS_OFFSET_NAME(12),
 291         REGS_OFFSET_NAME(13),
 292         REGS_OFFSET_NAME(14),
 293         REGS_OFFSET_NAME(15),
 294         REG_OFFSET_NAME(pc),
 295         REG_OFFSET_NAME(pr),
 296         REG_OFFSET_NAME(sr),
 297         REG_OFFSET_NAME(gbr),
 298         REG_OFFSET_NAME(mach),
 299         REG_OFFSET_NAME(macl),
 300         REG_OFFSET_NAME(tra),
 301         REG_OFFSET_END,
 302 };
 303
 304 /*
 305  * These are our native regset flavours.
 306  */
 307 enum sh_regset {
 308         REGSET_GENERAL,
 309 #ifdef CONFIG_SH_FPU
 310         REGSET_FPU,
 311 #endif
 312 #ifdef CONFIG_SH_DSP
 313         REGSET_DSP,
 314 #endif
 315 };
 316
 317 static const struct user_regset sh_regsets[] = {
 318         /*
 319          * Format is:
 320          *      R0 --> R15
 321          *      PC, PR, SR, GBR, MACH, MACL, TRA
 322          */
 323         [REGSET_GENERAL] = {
 324                 .core_note_type = NT_PRSTATUS,
 325                 .n              = ELF_NGREG,
 326                 .size           = sizeof(long),
 327                 .align          = sizeof(long),
 328                 .get            = genregs_get,
 329                 .set            = genregs_set,
 330         },
 331
 332 #ifdef CONFIG_SH_FPU
 333         [REGSET_FPU] = {
 334                 .core_note_type = NT_PRFPREG,
 335                 .n              = sizeof(struct user_fpu_struct) / sizeof(long),
 336                 .size           = sizeof(long),
 337                 .align          = sizeof(long),
 338                 .get            = fpregs_get,
 339                 .set            = fpregs_set,
 340                 .active         = fpregs_active,
 341         },
 342 #endif
 343
 344 #ifdef CONFIG_SH_DSP
 345         [REGSET_DSP] = {
 346                 .n              = sizeof(struct pt_dspregs) / sizeof(long),
 347                 .size           = sizeof(long),
 348                 .align          = sizeof(long),
 349                 .get            = dspregs_get,
 350                 .set            = dspregs_set,
 351                 .active         = dspregs_active,
 352         },
 353 #endif
 354 };
 355
 356 static const struct user_regset_view user_sh_native_view = {
 357         .name           = "sh",
 358         .e_machine      = EM_SH,
 359         .regsets        = sh_regsets,
 360         .n              = ARRAY_SIZE(sh_regsets),
 361 };
 362
 363 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 364 {
 365         return &user_sh_native_view;
 366 }
 367
 368 long arch_ptrace(struct task_struct *child, long request,
 369                  unsigned long addr, unsigned long data)
 370 {
 371         unsigned long __user *datap = (unsigned long __user *)data;
 372         int ret;
 373
 374         switch (request) {
 375         /* read the word at location addr in the USER area. */
 376         case PTRACE_PEEKUSR: {
 377                 unsigned long tmp;
 378
 379                 ret = -EIO;
 380                 if ((addr & 3) || addr < 0 ||
 381                     addr > sizeof(struct user) - 3)
 382                         break;
 383
 384                 if (addr < sizeof(struct pt_regs))
 385                         tmp = get_stack_long(child, addr);
 386                 else if (addr >= offsetof(struct user, fpu) &&
 387                          addr < offsetof(struct user, u_fpvalid)) {
 388                         if (!tsk_used_math(child)) {
 389                                 if (addr == offsetof(struct user, fpu.fpscr))
 390                                         tmp = FPSCR_INIT;
 391                                 else
 392                                         tmp = 0;
 393                         } else {
 394                                 unsigned long index;
 395                                 ret = init_fpu(child);
 396                                 if (ret)
 397                                         break;
 398                                 index = addr - offsetof(struct user, fpu);
 399                                 tmp = ((unsigned long *)child->thread.xstate)
 400                                         [index >> 2];
 401                         }
 402                 } else if (addr == offsetof(struct user, u_fpvalid))
 403                         tmp = !!tsk_used_math(child);
 404                 else if (addr == PT_TEXT_ADDR)
 405                         tmp = child->mm->start_code;
 406                 else if (addr == PT_DATA_ADDR)
 407                         tmp = child->mm->start_data;
 408                 else if (addr == PT_TEXT_END_ADDR)
 409                         tmp = child->mm->end_code;
 410                 else if (addr == PT_TEXT_LEN)
 411                         tmp = child->mm->end_code - child->mm->start_code;
 412                 else
 413                         tmp = 0;
 414                 ret = put_user(tmp, datap);
 415                 break;
 416         }
 417
 418         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 419                 ret = -EIO;
 420                 if ((addr & 3) || addr < 0 ||
 421                     addr > sizeof(struct user) - 3)
 422                         break;
 423
 424                 if (addr < sizeof(struct pt_regs))
 425                         ret = put_stack_long(child, addr, data);
 426                 else if (addr >= offsetof(struct user, fpu) &&
 427                          addr < offsetof(struct user, u_fpvalid)) {
 428                         unsigned long index;
 429                         ret = init_fpu(child);
 430                         if (ret)
 431                                 break;
 432                         index = addr - offsetof(struct user, fpu);
 433                         set_stopped_child_used_math(child);
 434                         ((unsigned long *)child->thread.xstate)
 435                                 [index >> 2] = data;
 436                         ret = 0;
 437                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 438                         conditional_stopped_child_used_math(data, child);
 439                         ret = 0;
 440                 }
 441                 break;
 442
 443         case PTRACE_GETREGS:
 444                 return copy_regset_to_user(child, &user_sh_native_view,
 445                                            REGSET_GENERAL,
 446                                            0, sizeof(struct pt_regs),
 447                                            datap);
 448         case PTRACE_SETREGS:
 449                 return copy_regset_from_user(child, &user_sh_native_view,
 450                                              REGSET_GENERAL,
 451                                              0, sizeof(struct pt_regs),
 452                                              datap);
 453 #ifdef CONFIG_SH_FPU
 454         case PTRACE_GETFPREGS:
 455                 return copy_regset_to_user(child, &user_sh_native_view,
 456                                            REGSET_FPU,
 457                                            0, sizeof(struct user_fpu_struct),
 458                                            datap);
 459         case PTRACE_SETFPREGS:
 460                 return copy_regset_from_user(child, &user_sh_native_view,
 461                                              REGSET_FPU,
 462                                              0, sizeof(struct user_fpu_struct),
 463                                              datap);
 464 #endif
 465 #ifdef CONFIG_SH_DSP
 466         case PTRACE_GETDSPREGS:
 467                 return copy_regset_to_user(child, &user_sh_native_view,
 468                                            REGSET_DSP,
 469                                            0, sizeof(struct pt_dspregs),
 470                                            datap);
 471         case PTRACE_SETDSPREGS:
 472                 return copy_regset_from_user(child, &user_sh_native_view,
 473                                              REGSET_DSP,
 474                                              0, sizeof(struct pt_dspregs),
 475                                              datap);
 476 #endif
 477         default:
 478                 ret = ptrace_request(child, request, addr, data);
 479                 break;
 480         }
 481
 482         return ret;
 483 }
 484
 485 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 486 {
 487         long ret = 0;
 488
 489         secure_computing_strict(regs->regs[0]);
 490
 491         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 492             tracehook_report_syscall_entry(regs))
 493                 /*
 494                  * Tracing decided this syscall should not happen.
 495                  * We'll return a bogus call number to get an ENOSYS
 496                  * error, but leave the original number in regs->regs[0].
 497                  */
 498                 ret = -1L;
 499
 500         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 501                 trace_sys_enter(regs, regs->regs[0]);
 502
 503         audit_syscall_entry(regs->regs[3], regs->regs[4], regs->regs[5],
 504                             regs->regs[6], regs->regs[7]);
 505
 506         return ret ?: regs->regs[0];
 507 }
 508
 509 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 510 {
 511         int step;
 512
 513         audit_syscall_exit(regs);
 514
 515         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 516                 trace_sys_exit(regs, regs->regs[0]);
 517
 518         step = test_thread_flag(TIF_SINGLESTEP);
 519         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 520                 tracehook_report_syscall_exit(regs, step);
 521 }