arch/sh/kernel/ptrace_32.c

   1 /*
   2  * SuperH process tracing
   3  *
   4  * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   5  * Copyright (C) 2002 - 2009  Paul Mundt
   6  *
   7  * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/smp.h>
  17 #include <linux/errno.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <linux/security.h>
  21 #include <linux/signal.h>
  22 #include <linux/io.h>
  23 #include <linux/audit.h>
  24 #include <linux/seccomp.h>
  25 #include <linux/tracehook.h>
  26 #include <linux/elf.h>
  27 #include <linux/regset.h>
  28 #include <linux/hw_breakpoint.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/system.h>
  32 #include <asm/processor.h>
  33 #include <asm/mmu_context.h>
  34 #include <asm/syscalls.h>
  35 #include <asm/fpu.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/syscalls.h>
  39
  40 /*
  41  * This routine will get a word off of the process kernel stack.
  42  */
  43 static inline int get_stack_long(struct task_struct *task, int offset)
  44 {
  45         unsigned char *stack;
  46
  47         stack = (unsigned char *)task_pt_regs(task);
  48         stack += offset;
  49         return (*((int *)stack));
  50 }
  51
  52 /*
  53  * This routine will put a word on the process kernel stack.
  54  */
  55 static inline int put_stack_long(struct task_struct *task, int offset,
  56                                  unsigned long data)
  57 {
  58         unsigned char *stack;
  59
  60         stack = (unsigned char *)task_pt_regs(task);
  61         stack += offset;
  62         *(unsigned long *) stack = data;
  63         return 0;
  64 }
  65
  66 void ptrace_triggered(struct perf_event *bp,
  67                       struct perf_sample_data *data, struct pt_regs *regs)
  68 {
  69         struct perf_event_attr attr;
  70
  71         /*
  72          * Disable the breakpoint request here since ptrace has defined a
  73          * one-shot behaviour for breakpoint exceptions.
  74          */
  75         attr = bp->attr;
  76         attr.disabled = true;
  77         modify_user_hw_breakpoint(bp, &attr);
  78 }
  79
  80 static int set_single_step(struct task_struct *tsk, unsigned long addr)
  81 {
  82         struct thread_struct *thread = &tsk->thread;
  83         struct perf_event *bp;
  84         struct perf_event_attr attr;
  85
  86         bp = thread->ptrace_bps[0];
  87         if (!bp) {
  88                 ptrace_breakpoint_init(&attr);
  89
  90                 attr.bp_addr = addr;
  91                 attr.bp_len = HW_BREAKPOINT_LEN_2;
  92                 attr.bp_type = HW_BREAKPOINT_R;
  93
  94                 bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
  95                                                  NULL, tsk);
  96                 if (IS_ERR(bp))
  97                         return PTR_ERR(bp);
  98
  99                 thread->ptrace_bps[0] = bp;
 100         } else {
 101                 int err;
 102
 103                 attr = bp->attr;
 104                 attr.bp_addr = addr;
 105                 /* reenable breakpoint */
 106                 attr.disabled = false;
 107                 err = modify_user_hw_breakpoint(bp, &attr);
 108                 if (unlikely(err))
 109                         return err;
 110         }
 111
 112         return 0;
 113 }
 114
 115 void user_enable_single_step(struct task_struct *child)
 116 {
 117         unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));
 118
 119         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 120
 121         if (ptrace_get_breakpoints(child) < 0)
 122                 return;
 123
 124         set_single_step(child, pc);
 125         ptrace_put_breakpoints(child);
 126 }
 127
 128 void user_disable_single_step(struct task_struct *child)
 129 {
 130         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 131 }
 132
 133 /*
 134  * Called by kernel/ptrace.c when detaching..
 135  *
 136  * Make sure single step bits etc are not set.
 137  */
 138 void ptrace_disable(struct task_struct *child)
 139 {
 140         user_disable_single_step(child);
 141 }
 142
 143 static int genregs_get(struct task_struct *target,
 144                        const struct user_regset *regset,
 145                        unsigned int pos, unsigned int count,
 146                        void *kbuf, void __user *ubuf)
 147 {
 148         const struct pt_regs *regs = task_pt_regs(target);
 149         int ret;
 150
 151         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 152                                   regs->regs,
 153                                   0, 16 * sizeof(unsigned long));
 154         if (!ret)
 155                 /* PC, PR, SR, GBR, MACH, MACL, TRA */
 156                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 157                                           &regs->pc,
 158                                           offsetof(struct pt_regs, pc),
 159                                           sizeof(struct pt_regs));
 160         if (!ret)
 161                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 162                                                sizeof(struct pt_regs), -1);
 163
 164         return ret;
 165 }
 166
 167 static int genregs_set(struct task_struct *target,
 168                        const struct user_regset *regset,
 169                        unsigned int pos, unsigned int count,
 170                        const void *kbuf, const void __user *ubuf)
 171 {
 172         struct pt_regs *regs = task_pt_regs(target);
 173         int ret;
 174
 175         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 176                                  regs->regs,
 177                                  0, 16 * sizeof(unsigned long));
 178         if (!ret && count > 0)
 179                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 180                                          &regs->pc,
 181                                          offsetof(struct pt_regs, pc),
 182                                          sizeof(struct pt_regs));
 183         if (!ret)
 184                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 185                                                 sizeof(struct pt_regs), -1);
 186
 187         return ret;
 188 }
 189
 190 #ifdef CONFIG_SH_FPU
 191 int fpregs_get(struct task_struct *target,
 192                const struct user_regset *regset,
 193                unsigned int pos, unsigned int count,
 194                void *kbuf, void __user *ubuf)
 195 {
 196         int ret;
 197
 198         ret = init_fpu(target);
 199         if (ret)
 200                 return ret;
 201
 202         if ((boot_cpu_data.flags & CPU_HAS_FPU))
 203                 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 204                                            &target->thread.xstate->hardfpu, 0, -1);
 205
 206         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 207                                    &target->thread.xstate->softfpu, 0, -1);
 208 }
 209
 210 static int fpregs_set(struct task_struct *target,
 211                        const struct user_regset *regset,
 212                        unsigned int pos, unsigned int count,
 213                        const void *kbuf, const void __user *ubuf)
 214 {
 215         int ret;
 216
 217         ret = init_fpu(target);
 218         if (ret)
 219                 return ret;
 220
 221         set_stopped_child_used_math(target);
 222
 223         if ((boot_cpu_data.flags & CPU_HAS_FPU))
 224                 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 225                                           &target->thread.xstate->hardfpu, 0, -1);
 226
 227         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 228                                   &target->thread.xstate->softfpu, 0, -1);
 229 }
 230
 231 static int fpregs_active(struct task_struct *target,
 232                          const struct user_regset *regset)
 233 {
 234         return tsk_used_math(target) ? regset->n : 0;
 235 }
 236 #endif
 237
 238 #ifdef CONFIG_SH_DSP
 239 static int dspregs_get(struct task_struct *target,
 240                        const struct user_regset *regset,
 241                        unsigned int pos, unsigned int count,
 242                        void *kbuf, void __user *ubuf)
 243 {
 244         const struct pt_dspregs *regs =
 245                 (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
 246         int ret;
 247
 248         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs,
 249                                   0, sizeof(struct pt_dspregs));
 250         if (!ret)
 251                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 252                                                sizeof(struct pt_dspregs), -1);
 253
 254         return ret;
 255 }
 256
 257 static int dspregs_set(struct task_struct *target,
 258                        const struct user_regset *regset,
 259                        unsigned int pos, unsigned int count,
 260                        const void *kbuf, const void __user *ubuf)
 261 {
 262         struct pt_dspregs *regs =
 263                 (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
 264         int ret;
 265
 266         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
 267                                  0, sizeof(struct pt_dspregs));
 268         if (!ret)
 269                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 270                                                 sizeof(struct pt_dspregs), -1);
 271
 272         return ret;
 273 }
 274
 275 static int dspregs_active(struct task_struct *target,
 276                           const struct user_regset *regset)
 277 {
 278         struct pt_regs *regs = task_pt_regs(target);
 279
 280         return regs->sr & SR_DSP ? regset->n : 0;
 281 }
 282 #endif
 283
 284 const struct pt_regs_offset regoffset_table[] = {
 285         REGS_OFFSET_NAME(0),
 286         REGS_OFFSET_NAME(1),
 287         REGS_OFFSET_NAME(2),
 288         REGS_OFFSET_NAME(3),
 289         REGS_OFFSET_NAME(4),
 290         REGS_OFFSET_NAME(5),
 291         REGS_OFFSET_NAME(6),
 292         REGS_OFFSET_NAME(7),
 293         REGS_OFFSET_NAME(8),
 294         REGS_OFFSET_NAME(9),
 295         REGS_OFFSET_NAME(10),
 296         REGS_OFFSET_NAME(11),
 297         REGS_OFFSET_NAME(12),
 298         REGS_OFFSET_NAME(13),
 299         REGS_OFFSET_NAME(14),
 300         REGS_OFFSET_NAME(15),
 301         REG_OFFSET_NAME(pc),
 302         REG_OFFSET_NAME(pr),
 303         REG_OFFSET_NAME(sr),
 304         REG_OFFSET_NAME(gbr),
 305         REG_OFFSET_NAME(mach),
 306         REG_OFFSET_NAME(macl),
 307         REG_OFFSET_NAME(tra),
 308         REG_OFFSET_END,
 309 };
 310
 311 /*
 312  * These are our native regset flavours.
 313  */
 314 enum sh_regset {
 315         REGSET_GENERAL,
 316 #ifdef CONFIG_SH_FPU
 317         REGSET_FPU,
 318 #endif
 319 #ifdef CONFIG_SH_DSP
 320         REGSET_DSP,
 321 #endif
 322 };
 323
 324 static const struct user_regset sh_regsets[] = {
 325         /*
 326          * Format is:
 327          *      R0 --> R15
 328          *      PC, PR, SR, GBR, MACH, MACL, TRA
 329          */
 330         [REGSET_GENERAL] = {
 331                 .core_note_type = NT_PRSTATUS,
 332                 .n              = ELF_NGREG,
 333                 .size           = sizeof(long),
 334                 .align          = sizeof(long),
 335                 .get            = genregs_get,
 336                 .set            = genregs_set,
 337         },
 338
 339 #ifdef CONFIG_SH_FPU
 340         [REGSET_FPU] = {
 341                 .core_note_type = NT_PRFPREG,
 342                 .n              = sizeof(struct user_fpu_struct) / sizeof(long),
 343                 .size           = sizeof(long),
 344                 .align          = sizeof(long),
 345                 .get            = fpregs_get,
 346                 .set            = fpregs_set,
 347                 .active         = fpregs_active,
 348         },
 349 #endif
 350
 351 #ifdef CONFIG_SH_DSP
 352         [REGSET_DSP] = {
 353                 .n              = sizeof(struct pt_dspregs) / sizeof(long),
 354                 .size           = sizeof(long),
 355                 .align          = sizeof(long),
 356                 .get            = dspregs_get,
 357                 .set            = dspregs_set,
 358                 .active         = dspregs_active,
 359         },
 360 #endif
 361 };
 362
 363 static const struct user_regset_view user_sh_native_view = {
 364         .name           = "sh",
 365         .e_machine      = EM_SH,
 366         .regsets        = sh_regsets,
 367         .n              = ARRAY_SIZE(sh_regsets),
 368 };
 369
 370 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 371 {
 372         return &user_sh_native_view;
 373 }
 374
 375 long arch_ptrace(struct task_struct *child, long request,
 376                  unsigned long addr, unsigned long data)
 377 {
 378         unsigned long __user *datap = (unsigned long __user *)data;
 379         int ret;
 380
 381         switch (request) {
 382         /* read the word at location addr in the USER area. */
 383         case PTRACE_PEEKUSR: {
 384                 unsigned long tmp;
 385
 386                 ret = -EIO;
 387                 if ((addr & 3) || addr < 0 ||
 388                     addr > sizeof(struct user) - 3)
 389                         break;
 390
 391                 if (addr < sizeof(struct pt_regs))
 392                         tmp = get_stack_long(child, addr);
 393                 else if (addr >= offsetof(struct user, fpu) &&
 394                          addr < offsetof(struct user, u_fpvalid)) {
 395                         if (!tsk_used_math(child)) {
 396                                 if (addr == offsetof(struct user, fpu.fpscr))
 397                                         tmp = FPSCR_INIT;
 398                                 else
 399                                         tmp = 0;
 400                         } else {
 401                                 unsigned long index;
 402                                 ret = init_fpu(child);
 403                                 if (ret)
 404                                         break;
 405                                 index = addr - offsetof(struct user, fpu);
 406                                 tmp = ((unsigned long *)child->thread.xstate)
 407                                         [index >> 2];
 408                         }
 409                 } else if (addr == offsetof(struct user, u_fpvalid))
 410                         tmp = !!tsk_used_math(child);
 411                 else if (addr == PT_TEXT_ADDR)
 412                         tmp = child->mm->start_code;
 413                 else if (addr == PT_DATA_ADDR)
 414                         tmp = child->mm->start_data;
 415                 else if (addr == PT_TEXT_END_ADDR)
 416                         tmp = child->mm->end_code;
 417                 else if (addr == PT_TEXT_LEN)
 418                         tmp = child->mm->end_code - child->mm->start_code;
 419                 else
 420                         tmp = 0;
 421                 ret = put_user(tmp, datap);
 422                 break;
 423         }
 424
 425         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 426                 ret = -EIO;
 427                 if ((addr & 3) || addr < 0 ||
 428                     addr > sizeof(struct user) - 3)
 429                         break;
 430
 431                 if (addr < sizeof(struct pt_regs))
 432                         ret = put_stack_long(child, addr, data);
 433                 else if (addr >= offsetof(struct user, fpu) &&
 434                          addr < offsetof(struct user, u_fpvalid)) {
 435                         unsigned long index;
 436                         ret = init_fpu(child);
 437                         if (ret)
 438                                 break;
 439                         index = addr - offsetof(struct user, fpu);
 440                         set_stopped_child_used_math(child);
 441                         ((unsigned long *)child->thread.xstate)
 442                                 [index >> 2] = data;
 443                         ret = 0;
 444                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 445                         conditional_stopped_child_used_math(data, child);
 446                         ret = 0;
 447                 }
 448                 break;
 449
 450         case PTRACE_GETREGS:
 451                 return copy_regset_to_user(child, &user_sh_native_view,
 452                                            REGSET_GENERAL,
 453                                            0, sizeof(struct pt_regs),
 454                                            datap);
 455         case PTRACE_SETREGS:
 456                 return copy_regset_from_user(child, &user_sh_native_view,
 457                                              REGSET_GENERAL,
 458                                              0, sizeof(struct pt_regs),
 459                                              datap);
 460 #ifdef CONFIG_SH_FPU
 461         case PTRACE_GETFPREGS:
 462                 return copy_regset_to_user(child, &user_sh_native_view,
 463                                            REGSET_FPU,
 464                                            0, sizeof(struct user_fpu_struct),
 465                                            datap);
 466         case PTRACE_SETFPREGS:
 467                 return copy_regset_from_user(child, &user_sh_native_view,
 468                                              REGSET_FPU,
 469                                              0, sizeof(struct user_fpu_struct),
 470                                              datap);
 471 #endif
 472 #ifdef CONFIG_SH_DSP
 473         case PTRACE_GETDSPREGS:
 474                 return copy_regset_to_user(child, &user_sh_native_view,
 475                                            REGSET_DSP,
 476                                            0, sizeof(struct pt_dspregs),
 477                                            datap);
 478         case PTRACE_SETDSPREGS:
 479                 return copy_regset_from_user(child, &user_sh_native_view,
 480                                              REGSET_DSP,
 481                                              0, sizeof(struct pt_dspregs),
 482                                              datap);
 483 #endif
 484         default:
 485                 ret = ptrace_request(child, request, addr, data);
 486                 break;
 487         }
 488
 489         return ret;
 490 }
 491
 492 static inline int audit_arch(void)
 493 {
 494         int arch = EM_SH;
 495
 496 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 497         arch |= __AUDIT_ARCH_LE;
 498 #endif
 499
 500         return arch;
 501 }
 502
 503 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 504 {
 505         long ret = 0;
 506
 507         secure_computing(regs->regs[0]);
 508
 509         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 510             tracehook_report_syscall_entry(regs))
 511                 /*
 512                  * Tracing decided this syscall should not happen.
 513                  * We'll return a bogus call number to get an ENOSYS
 514                  * error, but leave the original number in regs->regs[0].
 515                  */
 516                 ret = -1L;
 517
 518         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 519                 trace_sys_enter(regs, regs->regs[0]);
 520
 521         if (unlikely(current->audit_context))
 522                 audit_syscall_entry(audit_arch(), regs->regs[3],
 523                                     regs->regs[4], regs->regs[5],
 524                                     regs->regs[6], regs->regs[7]);
 525
 526         return ret ?: regs->regs[0];
 527 }
 528
 529 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 530 {
 531         int step;
 532
 533         if (unlikely(current->audit_context))
 534                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
 535                                    regs->regs[0]);
 536
 537         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 538                 trace_sys_exit(regs, regs->regs[0]);
 539
 540         step = test_thread_flag(TIF_SINGLESTEP);
 541         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 542                 tracehook_report_syscall_exit(regs, step);
 543 }