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