arch/sh/kernel/ptrace_64.c

   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/smp_lock.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/system.h>
  38 #include <asm/processor.h>
  39 #include <asm/mmu_context.h>
  40 #include <asm/syscalls.h>
  41 #include <asm/fpu.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  */
  58 static 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
  67 static inline unsigned long
  68 get_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.fpu)[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  */
  98 static 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
 109 static inline int
 110 put_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                 fpinit(&task->thread.fpu.hard);
 118                 set_stopped_child_used_math(task);
 119         } else if (last_task_used_math == task) {
 120                 enable_fpu();
 121                 save_fpu(task);
 122                 disable_fpu();
 123                 last_task_used_math = 0;
 124                 regs->sr |= SR_FD;
 125         }
 126
 127         ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
 128         return 0;
 129 }
 130
 131 void user_enable_single_step(struct task_struct *child)
 132 {
 133         struct pt_regs *regs = child->thread.uregs;
 134
 135         regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */
 136
 137         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 138 }
 139
 140 void user_disable_single_step(struct task_struct *child)
 141 {
 142         struct pt_regs *regs = child->thread.uregs;
 143
 144         regs->sr &= ~SR_SSTEP;
 145
 146         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 147 }
 148
 149 static int genregs_get(struct task_struct *target,
 150                        const struct user_regset *regset,
 151                        unsigned int pos, unsigned int count,
 152                        void *kbuf, void __user *ubuf)
 153 {
 154         const struct pt_regs *regs = task_pt_regs(target);
 155         int ret;
 156
 157         /* PC, SR, SYSCALL */
 158         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 159                                   &regs->pc,
 160                                   0, 3 * sizeof(unsigned long long));
 161
 162         /* R1 -> R63 */
 163         if (!ret)
 164                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 165                                           regs->regs,
 166                                           offsetof(struct pt_regs, regs[0]),
 167                                           63 * sizeof(unsigned long long));
 168         /* TR0 -> TR7 */
 169         if (!ret)
 170                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 171                                           regs->tregs,
 172                                           offsetof(struct pt_regs, tregs[0]),
 173                                           8 * sizeof(unsigned long long));
 174
 175         if (!ret)
 176                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 177                                                sizeof(struct pt_regs), -1);
 178
 179         return ret;
 180 }
 181
 182 static int genregs_set(struct task_struct *target,
 183                        const struct user_regset *regset,
 184                        unsigned int pos, unsigned int count,
 185                        const void *kbuf, const void __user *ubuf)
 186 {
 187         struct pt_regs *regs = task_pt_regs(target);
 188         int ret;
 189
 190         /* PC, SR, SYSCALL */
 191         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 192                                  &regs->pc,
 193                                  0, 3 * sizeof(unsigned long long));
 194
 195         /* R1 -> R63 */
 196         if (!ret && count > 0)
 197                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 198                                          regs->regs,
 199                                          offsetof(struct pt_regs, regs[0]),
 200                                          63 * sizeof(unsigned long long));
 201
 202         /* TR0 -> TR7 */
 203         if (!ret && count > 0)
 204                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 205                                          regs->tregs,
 206                                          offsetof(struct pt_regs, tregs[0]),
 207                                          8 * sizeof(unsigned long long));
 208
 209         if (!ret)
 210                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 211                                                 sizeof(struct pt_regs), -1);
 212
 213         return ret;
 214 }
 215
 216 #ifdef CONFIG_SH_FPU
 217 int fpregs_get(struct task_struct *target,
 218                const struct user_regset *regset,
 219                unsigned int pos, unsigned int count,
 220                void *kbuf, void __user *ubuf)
 221 {
 222         int ret;
 223
 224         ret = init_fpu(target);
 225         if (ret)
 226                 return ret;
 227
 228         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 229                                    &target->thread.fpu.hard, 0, -1);
 230 }
 231
 232 static int fpregs_set(struct task_struct *target,
 233                        const struct user_regset *regset,
 234                        unsigned int pos, unsigned int count,
 235                        const void *kbuf, const void __user *ubuf)
 236 {
 237         int ret;
 238
 239         ret = init_fpu(target);
 240         if (ret)
 241                 return ret;
 242
 243         set_stopped_child_used_math(target);
 244
 245         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 246                                   &target->thread.fpu.hard, 0, -1);
 247 }
 248
 249 static int fpregs_active(struct task_struct *target,
 250                          const struct user_regset *regset)
 251 {
 252         return tsk_used_math(target) ? regset->n : 0;
 253 }
 254 #endif
 255
 256 /*
 257  * These are our native regset flavours.
 258  */
 259 enum sh_regset {
 260         REGSET_GENERAL,
 261 #ifdef CONFIG_SH_FPU
 262         REGSET_FPU,
 263 #endif
 264 };
 265
 266 static const struct user_regset sh_regsets[] = {
 267         /*
 268          * Format is:
 269          *      PC, SR, SYSCALL,
 270          *      R1 --> R63,
 271          *      TR0 --> TR7,
 272          */
 273         [REGSET_GENERAL] = {
 274                 .core_note_type = NT_PRSTATUS,
 275                 .n              = ELF_NGREG,
 276                 .size           = sizeof(long long),
 277                 .align          = sizeof(long long),
 278                 .get            = genregs_get,
 279                 .set            = genregs_set,
 280         },
 281
 282 #ifdef CONFIG_SH_FPU
 283         [REGSET_FPU] = {
 284                 .core_note_type = NT_PRFPREG,
 285                 .n              = sizeof(struct user_fpu_struct) /
 286                                   sizeof(long long),
 287                 .size           = sizeof(long long),
 288                 .align          = sizeof(long long),
 289                 .get            = fpregs_get,
 290                 .set            = fpregs_set,
 291                 .active         = fpregs_active,
 292         },
 293 #endif
 294 };
 295
 296 static const struct user_regset_view user_sh64_native_view = {
 297         .name           = "sh64",
 298         .e_machine      = EM_SH,
 299         .regsets        = sh_regsets,
 300         .n              = ARRAY_SIZE(sh_regsets),
 301 };
 302
 303 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 304 {
 305         return &user_sh64_native_view;
 306 }
 307
 308 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 309 {
 310         int ret;
 311
 312         switch (request) {
 313         /* read the word at location addr in the USER area. */
 314         case PTRACE_PEEKUSR: {
 315                 unsigned long tmp;
 316
 317                 ret = -EIO;
 318                 if ((addr & 3) || addr < 0)
 319                         break;
 320
 321                 if (addr < sizeof(struct pt_regs))
 322                         tmp = get_stack_long(child, addr);
 323                 else if ((addr >= offsetof(struct user, fpu)) &&
 324                          (addr <  offsetof(struct user, u_fpvalid))) {
 325                         tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
 326                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 327                         tmp = !!tsk_used_math(child);
 328                 } else {
 329                         break;
 330                 }
 331                 ret = put_user(tmp, (unsigned long *)data);
 332                 break;
 333         }
 334
 335         case PTRACE_POKEUSR:
 336                 /* write the word at location addr in the USER area. We must
 337                    disallow any changes to certain SR bits or u_fpvalid, since
 338                    this could crash the kernel or result in a security
 339                    loophole. */
 340                 ret = -EIO;
 341                 if ((addr & 3) || addr < 0)
 342                         break;
 343
 344                 if (addr < sizeof(struct pt_regs)) {
 345                         /* Ignore change of top 32 bits of SR */
 346                         if (addr == offsetof (struct pt_regs, sr)+4)
 347                         {
 348                                 ret = 0;
 349                                 break;
 350                         }
 351                         /* If lower 32 bits of SR, ignore non-user bits */
 352                         if (addr == offsetof (struct pt_regs, sr))
 353                         {
 354                                 long cursr = get_stack_long(child, addr);
 355                                 data &= ~(SR_MASK);
 356                                 data |= (cursr & SR_MASK);
 357                         }
 358                         ret = put_stack_long(child, addr, data);
 359                 }
 360                 else if ((addr >= offsetof(struct user, fpu)) &&
 361                          (addr <  offsetof(struct user, u_fpvalid))) {
 362                         ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
 363                 }
 364                 break;
 365
 366         case PTRACE_GETREGS:
 367                 return copy_regset_to_user(child, &user_sh64_native_view,
 368                                            REGSET_GENERAL,
 369                                            0, sizeof(struct pt_regs),
 370                                            (void __user *)data);
 371         case PTRACE_SETREGS:
 372                 return copy_regset_from_user(child, &user_sh64_native_view,
 373                                              REGSET_GENERAL,
 374                                              0, sizeof(struct pt_regs),
 375                                              (const void __user *)data);
 376 #ifdef CONFIG_SH_FPU
 377         case PTRACE_GETFPREGS:
 378                 return copy_regset_to_user(child, &user_sh64_native_view,
 379                                            REGSET_FPU,
 380                                            0, sizeof(struct user_fpu_struct),
 381                                            (void __user *)data);
 382         case PTRACE_SETFPREGS:
 383                 return copy_regset_from_user(child, &user_sh64_native_view,
 384                                              REGSET_FPU,
 385                                              0, sizeof(struct user_fpu_struct),
 386                                              (const void __user *)data);
 387 #endif
 388         default:
 389                 ret = ptrace_request(child, request, addr, data);
 390                 break;
 391         }
 392
 393         return ret;
 394 }
 395
 396 asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
 397 {
 398 #define WPC_DBRMODE 0x0d104008
 399         static int first_call = 1;
 400
 401         lock_kernel();
 402         if (first_call) {
 403                 /* Set WPC.DBRMODE to 0.  This makes all debug events get
 404                  * delivered through RESVEC, i.e. into the handlers in entry.S.
 405                  * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
 406                  * would normally be left set to 1, which makes debug events get
 407                  * delivered through DBRVEC, i.e. into the remote gdb's
 408                  * handlers.  This prevents ptrace getting them, and confuses
 409                  * the remote gdb.) */
 410                 printk("DBRMODE set to 0 to permit native debugging\n");
 411                 poke_real_address_q(WPC_DBRMODE, 0);
 412                 first_call = 0;
 413         }
 414         unlock_kernel();
 415
 416         return sys_ptrace(request, pid, addr, data);
 417 }
 418
 419 static inline int audit_arch(void)
 420 {
 421         int arch = EM_SH;
 422
 423 #ifdef CONFIG_64BIT
 424         arch |= __AUDIT_ARCH_64BIT;
 425 #endif
 426 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 427         arch |= __AUDIT_ARCH_LE;
 428 #endif
 429
 430         return arch;
 431 }
 432
 433 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
 434 {
 435         long long ret = 0;
 436
 437         secure_computing(regs->regs[9]);
 438
 439         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 440             tracehook_report_syscall_entry(regs))
 441                 /*
 442                  * Tracing decided this syscall should not happen.
 443                  * We'll return a bogus call number to get an ENOSYS
 444                  * error, but leave the original number in regs->regs[0].
 445                  */
 446                 ret = -1LL;
 447
 448         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 449                 trace_sys_enter(regs, regs->regs[9]);
 450
 451         if (unlikely(current->audit_context))
 452                 audit_syscall_entry(audit_arch(), regs->regs[1],
 453                                     regs->regs[2], regs->regs[3],
 454                                     regs->regs[4], regs->regs[5]);
 455
 456         return ret ?: regs->regs[9];
 457 }
 458
 459 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 460 {
 461         int step;
 462
 463         if (unlikely(current->audit_context))
 464                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[9]),
 465                                    regs->regs[9]);
 466
 467         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 468                 trace_sys_exit(regs, regs->regs[9]);
 469
 470         step = test_thread_flag(TIF_SINGLESTEP);
 471         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 472                 tracehook_report_syscall_exit(regs, step);
 473 }
 474
 475 /* Called with interrupts disabled */
 476 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 477 {
 478         /* This is called after a single step exception (DEBUGSS).
 479            There is no need to change the PC, as it is a post-execution
 480            exception, as entry.S does not do anything to the PC for DEBUGSS.
 481            We need to clear the Single Step setting in SR to avoid
 482            continually stepping. */
 483         local_irq_enable();
 484         regs->sr &= ~SR_SSTEP;
 485         force_sig(SIGTRAP, current);
 486 }
 487
 488 /* Called with interrupts disabled */
 489 asmlinkage void do_software_break_point(unsigned long long vec,
 490                                         struct pt_regs *regs)
 491 {
 492         /* We need to forward step the PC, to counteract the backstep done
 493            in signal.c. */
 494         local_irq_enable();
 495         force_sig(SIGTRAP, current);
 496         regs->pc += 4;
 497 }
 498
 499 /*
 500  * Called by kernel/ptrace.c when detaching..
 501  *
 502  * Make sure single step bits etc are not set.
 503  */
 504 void ptrace_disable(struct task_struct *child)
 505 {
 506         user_disable_single_step(child);
 507 }